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Sample records for degradable starch microsphere

  1. Temporary ischaemia induced by degradable starch microspheres

    International Nuclear Information System (INIS)

    Lote, K.

    1981-01-01

    Possible thrombogenic effects of degradable starch microspheres were investigated. Controlled temporary small intestinal ischaemia was induced by injection into the superior mesenteric artery in cats. Arterial flow consistently recovered after ischaemia. No consumption of blood platelets, fibrinogen, or Factor VIII was observed. Aggregation of human platelets was not influenced by microsphere exposure, and platelet retention in starch microsphere columns was minimal. No thrombosis was detected in feline small intestinal vessels in vivo nor did starch surfaces induce adhesion or aggregation of human platelets in vitro. Thus, no evidence of thrombotic hazards was found by inducing temporary intestinal ischaemia by starch microspheres. (Auth.)

  2. Hypoxic radioprotection by temporary intestinal ischemia: degradable starch microsphere embolization in the cat

    Energy Technology Data Exchange (ETDEWEB)

    Lote, K.

    1981-11-01

    Temporary small intestinal ischemia was induced by mesenteric arteriolar embolization of degradable starch microspheres in cats. During ischemia, the small intestine received a surface dose of 7 Gy 200 kV x-ray irradiation. One group of animals also had received 7 Gy to the intact abdomen 72 hr earlier. The risk of thrombosis in small intestinal vessels during or after starch microsphere-induced ischemia combined with irradiation was evaluated by monitoring superior mesenteric arterial blood flow, by determination of blood platelets, fibrinogen, and factor VIII consumed across the mesenteric vascular bed, and by histologic examination of small intestinal vessels. Vascular integrity was inferred from intact response to isoproterenol and vasopressin after the combined trauma of ischemia and irradiation. No signs of thrombosis were detected in small intestinal vessels after temporary ischemia and irradiation. Hypoxic radioprotection of the small intestine in the cat can thus be achieved by mesenteric arterial microembolization of degradable starch spheres without evidence of thrombotic complications or significant vascular damage.

  3. Hypoxic radioprotection by temporary intestinal ischemia: degradable starch microsphere embolization in the cat

    International Nuclear Information System (INIS)

    Lote, K.

    1981-01-01

    Temporary small intestinal ischemia was induced by mesenteric arteriolar embolization of degradable starch microspheres in cats. During ischemia, the small intestine received a surface dose of 7 Gy 200 kV x-ray irradiation. One group of animals also had received 7 Gy to the intact abdomen 72 hr earlier. The risk of thrombosis in small intestinal vessels during or after starch microsphere-induced ischemia combined with irradiation was evaluated by monitoring superior mesenteric arterial blood flow, by determination of blood platelets, fibrinogen, and factor VIII consumed across the mesenteric vascular bed, and by histologic examination of small intestinal vessels. Vascular integrity was inferred from intact response to isoproterenol and vasopressin after the combined trauma of ischemia and irradiation. No signs of thrombosis were detected in small intestinal vessels after temporary ischemia and irradiation. Hypoxic radioprotection of the small intestine in the cat can thus be achieved by mesenteric arterial microembolization of degradable starch spheres without evidence of thrombotic complications of significant vascular damage

  4. Hypoxic radioprotection by temporary intestinal ischemia: degradable starch microsphere embolization in the cat

    International Nuclear Information System (INIS)

    Lote, K.

    1981-01-01

    Temporary small intestinal ischemia was induced by mesenteric arteriolar embolization of degradable starch microspheres in cats. During ischemia, the small intestine received a surface dose of 7 Gy 200 kV x-ray irradiation. One group of animals also had received 7 Gy to the intact abdomen 72 hr earlier. The risk of thrombosis in small intestinal vessels during or after starch microsphere-induced ischemia combined with irradiation was evaluated by monitoring superior mesenteric arterial blood flow, by determination of blood platelets, fibrinogen, and factor VIII consumed across the mesenteric vascular bed, and by histologic examination of small intestinal vessels. Vascular integrity was inferred from intact response to isoproterenol and vasopressin after the combined trauma of ischemia and irradiation. No signs of thrombosis were detected in small intestinal vessels after temporary ischemia and irradiation. Hypoxic radioprotection of the small intestine in the cat can thus be achieved by mesenteric arterial microembolization of degradable starch spheres without evidence of thrombotic complications or significant vascular damage

  5. Hypoxic radioprotection by temporary intestinal ischemia: degradable starch microsphere embolization in the cat

    Energy Technology Data Exchange (ETDEWEB)

    Lote, K.

    1981-01-01

    Temporary small intestinal ischemia was induced by mesenteric arteriolar embolization of degradable starch microspheres in cats. During ischemia, the small intestine received a surface dose of 7 Gy 200 kV x-ray irradiation. One group of animals also had received 7 Gy to the intact abdomen 72 hr earlier. The risk of thrombosis in small intestinal vessels during or after starch microsphere-induced ischemia combined with irradiation was evaluated by monitoring superior mesenteric arterial blood flow, by determination of blood platelets, fibrinogen, and factor VIII consumed across the mesenteric vascular bed, and by histologic examination of small intestinal vessels. Vascular integrity was inferred from intact response to isoproterenol and vasopressin after the combined trauma of ischemia and irradiation. No signs of thrombosis were detected in small intestinal vessels after temporary ischemia and irradiation. Hypoxic radioprotection of the small intestine in the cat can thus be achieved by mesenteric arterial microembolization of degradable starch spheres without evidence of thrombotic complications of significant vascular damage.

  6. A gamma camera method to monitor the use of degradable starch microspheres in hepatic arterial chemotherapy

    International Nuclear Information System (INIS)

    Britten, A.; Fleming, J.; Flowerdew, A.; Hunt, T.; Taylor, I.; Ackery, D.

    1989-01-01

    A gamma camera method to quantify the haemodynamic effects of degradable starch microspheres (DSM) in intra arterial hepatic therapy is described. Results are presented from ten patients with colorectal liver metastases. Intra hepatic arterio venous shunting was present in 1 patient prior to DSM and in 2 subjects after three 300 mg DSM fractions. DSM reduced the rate of flow of injectate to the lung in all cases. Conversely, an increased rate of flow of injectate to gut or spleen occurred with 300 mg fractions of DSM in 7/9 cases. Lower dose DSM fractions are indicated. At 2-3 min after DSM injection the mean fraction of the activity retained in the liver was 0.22. A DSM induced enhancement of tumour relative to normal tissue perfusion was obtained in four out of five tumour regions identified. All indices showed a wide variation between patients and between individual DSM doses, and the high incidence of extra hepatic shunting confirms the need for monitoring when using intra arterial microspheres. (orig.)

  7. 5-Fluorouracil incorporation into RNA of a rat liver adenocarcinoma after hepatic artery injection together with degradable starch microspheres

    International Nuclear Information System (INIS)

    Teder, H.; Erichsen, C.; Christensson, P.I.; Joensson, P.E.S.; Stenram, U.

    1987-01-01

    The effect of degradable starch microspheres (DSM) on the cellular incorporation of 5-fluorouracil (FUra) was studied in rats with solitary liver tumors. 3 H-labelled FUra [0.78 mg (6000 nmol)/kg b.wt.] was injected with saline or mixed with DSM, into the hepatic artery. Labelling of the acid soluble fraction (ASF), RNA and DNA of tumor, liver, bone marrow and small intestine was measured 60 minutes after injection. The DSM had no significant effect on the incorporation of FUra into the ASF or RNA, neither in tumor nor liver tissue. Regarding the tumor/normal tissue ratios of specific radioactivities, there was with DSM a higher tumor/liver and a higher tumor/bone marrow ratio in the ASF, indicating an increased tumour drug exposure with DSM. However, this was not accompanied by any significant increase in drug anabolism

  8. Pharmacokinetics and Histopathological Findings of Chemoembolization Using Cisplatin Powder Mixed with Degradable Starch Microspheres in a Rabbit Liver Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Takeshi; Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp; Nishiofuku, Hideyuki; Fukuoka, Yasushi [IVR CenterNara Medical University, Department of Radiology (Japan); Sakaguchi, Hiroshi [South Nara General Medical Center, Department of Radiology (Japan); Masada, Tetsuya; Tatsumoto, Shota [IVR CenterNara Medical University, Department of Radiology (Japan); Marugami, Nagaaki [Diagnostic Imaging Center, Department of Radiology (Japan); Takano, Masato [Nara Medical University, Department of Diagnostic Pathology (Japan); Yamato, Ichiro; Sho, Masayuki [Nara Medical University, Department of Surgery (Japan); Ohbayashi, Chiho [Nara Medical University, Department of Diagnostic Pathology (Japan); Hirai, Toshiko [Diagnostic Imaging Center, Department of Radiology (Japan); Kichikawa, Kimihiko [IVR CenterNara Medical University, Department of Radiology (Japan)

    2017-03-15

    PurposeThe purpose of this study is to evaluate the pharmacokinetics and histopathological findings of transarterial chemoembolization (TACE) using cisplatin powder mixed with degradable starch microspheres (DSM) (Cis/DSM-TACE) compared with cisplatin arterial infusion (Cis-AI).Materials and MethodsEighteen rabbits with VX2 liver tumors were divided into two groups: Cis/DSM-TACE (n = 9) and Cis-AI (n = 9) groups. In the Cis/DSM-TACE group, a mixture of cisplatin powder and DSM was injected until stasis of hepatic arterial flow was achieved. In the Cis-AI group, cisplatin solution was infused.ResultsThe platinum concentrations in VX2 tumors in the Cis/DSM-TACE group at 24 and 72 h were significantly elevated compared with those in the Cis-AI group (P = .016 and .019, respectively). There were no significant differences in the platinum concentrations in plasma. Histopathological examination revealed the presence of several microspheres inside the tumors at 1 h, which completely disappeared at 24 h. Tumor cell apoptosis at 1 h in the Cis/DSM-TACE group was more frequently observed compared with that in the Cis-AI group (P = .006).ConclusionsTACE using cisplatin powder mixed with DSM provides a higher drug concentration in tumors, thereby achieving stronger antitumor effects compared with arterial infusion of cisplatin solution.

  9. Pharmacokinetics and Histopathological Findings of Chemoembolization Using Cisplatin Powder Mixed with Degradable Starch Microspheres in a Rabbit Liver Tumor Model

    International Nuclear Information System (INIS)

    Sato, Takeshi; Tanaka, Toshihiro; Nishiofuku, Hideyuki; Fukuoka, Yasushi; Sakaguchi, Hiroshi; Masada, Tetsuya; Tatsumoto, Shota; Marugami, Nagaaki; Takano, Masato; Yamato, Ichiro; Sho, Masayuki; Ohbayashi, Chiho; Hirai, Toshiko; Kichikawa, Kimihiko

    2017-01-01

    PurposeThe purpose of this study is to evaluate the pharmacokinetics and histopathological findings of transarterial chemoembolization (TACE) using cisplatin powder mixed with degradable starch microspheres (DSM) (Cis/DSM-TACE) compared with cisplatin arterial infusion (Cis-AI).Materials and MethodsEighteen rabbits with VX2 liver tumors were divided into two groups: Cis/DSM-TACE (n = 9) and Cis-AI (n = 9) groups. In the Cis/DSM-TACE group, a mixture of cisplatin powder and DSM was injected until stasis of hepatic arterial flow was achieved. In the Cis-AI group, cisplatin solution was infused.ResultsThe platinum concentrations in VX2 tumors in the Cis/DSM-TACE group at 24 and 72 h were significantly elevated compared with those in the Cis-AI group (P = .016 and .019, respectively). There were no significant differences in the platinum concentrations in plasma. Histopathological examination revealed the presence of several microspheres inside the tumors at 1 h, which completely disappeared at 24 h. Tumor cell apoptosis at 1 h in the Cis/DSM-TACE group was more frequently observed compared with that in the Cis-AI group (P = .006).ConclusionsTACE using cisplatin powder mixed with DSM provides a higher drug concentration in tumors, thereby achieving stronger antitumor effects compared with arterial infusion of cisplatin solution.

  10. Feasibility of temporary protective embolization of normal liver tissue using degradable starch microspheres during radioembolization of liver tumours

    International Nuclear Information System (INIS)

    Meyer, Carsten; Pieper, Claus Christian; Wilhelm, Kai E.; Schild, Hans Heinz; Ezziddin, Samer; Ahmadzadehfar, Hojjat

    2014-01-01

    To describe a new approach to protect nontarget healthy liver tissue using degradable starch microspheres (DSM) as a short-term embolizate during radioembolization of liver tumours with 90 Y microspheres. Between December 2011 and July 2012 radioembolization was performed in 54 patients. Five of these patients (three women, two men; mean age 67 years) underwent protective temporary embolization using DSM (EmboCept registered S) of normal liver tissue that could not be excluded from the area treated by radioembolization through catheter repositioning. Clinical symptoms, laboratory findings, preinterventional imaging, and 99m Tc-MAA and bremsstrahlung SPECT/CT, as well as baseline and follow-up imaging with 18 F-FDG PET/CT and MRI, were evaluated in relation to the technical and clinical success of the protective embolization. Temporary embolization of arteries supplying normal liver tissue using DSM was technically successful in all five patients. 99m Tc-MAA SPECT/CT performed in the first two patients after DSM injection showed no increased pulmonary shunting compared to the MAA test injection without DSM. Bremsstrahlung SPECT/CT after radioembolization demonstrated satisfactory irradiation of the tumour and successful protection of normal liver tissue. There were only mild hepatotoxic effects (grade 1) on laboratory follow-up examinations, and no adverse events associated with DSM embolization or radioembolization were recorded. Temporary embolization with DSM before radioembolization is feasible and can effectively protect areas of normal liver tissue from irradiation and avoid permanent embolization if other methods such as catheter repositioning are not possible due to the location of the metastases. (orig.)

  11. Safety and efficacy of transarterial chemoembolization with degradable starch microspheres (DSM-TACE) in the treatment of secondary liver malignancies.

    Science.gov (United States)

    Schicho, Andreas; Pereira, Philippe L; Michalik, Katharina; Beyer, Lukas P; Stroszczynski, Christian; Wiggermann, Philipp

    2018-01-01

    To evaluate the safety and efficacy of degradable starch microspheres (DSM) as embolic agents in transarterial chemoembolization (TACE) in the treatment of secondary liver metastases. This was a national, multicenter observational study. Primary endpoints were safety and treatment response according to Modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. A total of 77 DSM-TACE procedures were performed in 20 patients. Minor immediate adverse events (AEs) were epigastric pain with an incidence of 45.5% (35/77), and nausea and vomiting at an incidence of 23.4% (18/77). Delayed minor AEs were epigastric pain in 13/77 (16.9%) treatments and nausea and vomiting in 10 (13.0%) treatments. No severe AEs were documented. Therapeutic efficacy of DSM-TACE procedures according to mRECIST was as follows: complete response 0/77, partial response 17/77, stable disease 33/77 and progressive disease 6/77, no data was available for 21/77 treatments. Overall, objective response was achieved in 8 of 20 patients (40.0%). DSM as embolic agent for TACE is safe in the treatment of liver metastases. An objective response in 40.0% of patients and disease control in 64.9% of procedures was achieved, and this should lead to further evaluation of DSM-TACE as treatment option for nonresectable liver metastases.

  12. Transcatheter arterial chemoembolization of colorectal liver metastases using degradable starch microspheres (Spherex registered). Own investigations and review to the literature

    International Nuclear Information System (INIS)

    Wasser, K.; Landwehr, P.

    2005-01-01

    Since two decades transarterial chemoembolization (TACE) of liver metastases has been investigated in numerous studies. However, no standardized therapeutic procedure exists so far. The present study retrospectively investigated survival, response and side effects after TACE of liver metastases in 21 patients with colorectal cancer and results are compared with previous literature. A total of 68 TACE procedures were performed. A suspension of degradable starch microspheres (DSM, Spherex registered ) and Mitomycin C was applied selectively into hepatic arteries via a transfemoral approach. DSM effect a temporary arterial occlusion. Follow-up studies were performed by contrast enhanced spiral computed tomography (CT). The median survival was 13.8 months. Therapeutic response (according to WHO) was observed only in three patients. The progression free interval was 5.8 months. Patients developed a postembolization-syndrome (abdominal pain, fever, nausea) and increased transaminases in 27-43% of all interventions. A gastric ulcer occurred after four, cholecystitis after two TACE. As already shown in most previous studies, regardless of the used agents, also this investigation underlines the moderate therapeutic effect of TACE on colorectal liver metastases. So far, no significant survival benefit has been shown in the literature and the response rates are rather limited. In general, complications of TACE seem to be rare, but should not to be underestimated. Compared to TACE with long or permanent arterial occlusion, postembolization syndrome seems to be less pronounced using DSM. As TACE is rather a palliative therapeutic approach, DSM therefore might be more suited. Further studies on TACE of liver metastases should focus on to the patients' quality of life. (orig.) [de

  13. Biodistribution of 10B in a rat liver tumor model following intra-arterial administration of sodium borocaptate (BSH)/degradable starch microspheres (DSM) emulsion

    International Nuclear Information System (INIS)

    Suzuki, Minoru; Nagata, Kenji; Masunaga, Shinichiro; Kinashi, Yuko; Sakurai, Yoshinori; Maruhashi, Akira; Ono, Koji

    2004-01-01

    We reported that intra-arterial administration of borocaptate sodium (BSH)/lipiodol emulsion provided selectively high 10 B concentrations (approximately 200 ppm 6 h after administration) in experimental liver tumors. In the present study, we investigated the pharmacokinetics of BSH following intra-arterial administration of BSH with other embolizing agent, degradable starch microspheres (DSM). The 10 B concentration in the tumor at 1 h after administration of BSH with DSM was 231 ppm. At 6 h, the 10 B concentration in the tumor in BSH with DSM group was 81.5 ppm. The 10 B concentration in the liver at 1 h after administration of BSH with DSM was 184 ppm. At 6 h, the 10 B concentration in the liver in BSH with DSM group was 78 ppm. The tumor/liver 10 B concentration ratios (T/L ratio) in the 'BSH+DSM' group were significantly smaller than those in the 'BSH+lipiodol' group at 1 h (1.4 vs. 3.6) and 6 h (1.1 vs. 14.9). BSH/DSM-boron neutron capture therapy (BNCT) was not suitable for treatment of multiple liver tumors due to the low T/L 10 B concentration ratio. However, the high 10 B accumulation in the liver tumors following intra-arterial administration of BSH/DSM emulsion suggests that BSH/DSM-BNCT has the potential for application to malignant tumors in other sites

  14. Radiofrequency Ablation Combined with Hepatic Arterial Chemoembolization Using Degradable Starch Microsphere Mixed with Mitomycin C for the Treatment of Liver Metastasis from Colorectal Cancer: A Prospective Multicenter Study

    Energy Technology Data Exchange (ETDEWEB)

    Yamakado, Koichiro, E-mail: yamakado47@gmail.com [Hyogo College of Medicine, Department of Radiology (Japan); Inaba, Yasutaka; Sato, Yozo [Aichi Cancer Center, Department of Radiology (Japan); Yasumoto, Taku [Toyonaka Municipal Hospital, Department of Radiology (Japan); Hayashi, Sadao [Kagoshima University, Department of Radiology (Japan); Yamanaka, Takashi [Mie University, Department of Radiology (Japan); Nobata, Koji [Kouseiren Takaoka Hospital, Department of Radiology (Japan); Takaki, Haruyuki [Hyogo College of Medicine, Department of Radiology (Japan); Nakatsuka, Atsuhiro [Mie University, Department of Radiology (Japan)

    2017-04-15

    PurposeThis phase II prospective study investigates possible benefits of radiofrequency ablation (RFA) combined with hepatic arterial chemoembolization using degradable starch microsphere (DSM) mixed with mitomycin C (MMC) in non-surgical candidates with colorectal liver metastases.Materials and MethodsThis study, approved by the respective institutional review board, included non-surgical candidates with 3 or fewer liver tumors of 3 cm or smaller, or a single lesion 5 cm or smaller. Percutaneous RFA was performed immediately after chemoembolization using DSM-MMC. Primary and secondary endpoints were the local tumor control rate, safety, and 2-year recurrence-free and overall survival rates.ResultsThis study examined 25 patients (22 males, 3 females) with 38 tumors of mean maximum diameter of 2.2 ± 0.9 cm (standard deviation) (range 1.0–4.2 cm). Their mean age was 70.2 ± 8.2 years (range 55–82 years). Local tumor progression developed in 3 tumors (7.9%, 3/38) of 3 patients (12%, 3/25) during the mean follow-up of 34.9 ± 9.2 months (range 18.3–50.1 months). The 2-year local tumor control rates were 92.0% [95% confidence interval (CI), 81.4–100%] on a patient basis and 94.6% (95% CI, 87.3–100%) on a tumor basis. The respective 2-year overall and recurrence-free survival rates were 88.0% (95% CI, 75.3–98.5%) and 63.3% (95% CI, 44.2–82.5%), with median survival time of 48.4 months. Fever was the only adverse event requiring treatments in 2 patients (8%).ConclusionsThis combination therapy is safe, exhibiting strong anticancer effects on colorectal liver metastasis, which might contribute to patient survival.

  15. Transcatheter arterial chemoembolization of colorectal liver metastases using degradable starch microspheres (Spherex {sup registered}). Own investigations and review to the literature; Transarterielle Chemoembolisation von Lebermetastasen kolorektaler Karzinome mit abbaubaren Staerkepartikeln (Spherex {sup registered}). Eigene Beobachtungen und Literaturuebersicht

    Energy Technology Data Exchange (ETDEWEB)

    Wasser, K. [Universitaetsklinikum Mannheim (Germany). Institut fuer Klinische Radiologie; Giebel, F. [Universitaetsklinikum Koeln (Germany). Klinik fuer Anaesthesiologie und Operative Intensivmedizin; Fischbach, R. [Universitaetsklinkum Muenster (Germany). Institut fuer Klinische Radiologie; Tesch, H. [Universitaetsklinikum Koeln (Germany). Medizinische Klinik I; Onkologische Gemeinschaftspraxis, Frankfurt (Germany); Landwehr, P. [Henriettenstiftung Hannover (Germany). Klinik fuer Diagnostische und interventionelle Radiologie

    2005-07-01

    Since two decades transarterial chemoembolization (TACE) of liver metastases has been investigated in numerous studies. However, no standardized therapeutic procedure exists so far. The present study retrospectively investigated survival, response and side effects after TACE of liver metastases in 21 patients with colorectal cancer and results are compared with previous literature. A total of 68 TACE procedures were performed. A suspension of degradable starch microspheres (DSM, Spherex {sup registered}) and Mitomycin C was applied selectively into hepatic arteries via a transfemoral approach. DSM effect a temporary arterial occlusion. Follow-up studies were performed by contrast enhanced spiral computed tomography (CT). The median survival was 13.8 months. Therapeutic response (according to WHO) was observed only in three patients. The progression free interval was 5.8 months. Patients developed a postembolization-syndrome (abdominal pain, fever, nausea) and increased transaminases in 27-43% of all interventions. A gastric ulcer occurred after four, cholecystitis after two TACE. As already shown in most previous studies, regardless of the used agents, also this investigation underlines the moderate therapeutic effect of TACE on colorectal liver metastases. So far, no significant survival benefit has been shown in the literature and the response rates are rather limited. In general, complications of TACE seem to be rare, but should not to be underestimated. Compared to TACE with long or permanent arterial occlusion, postembolization syndrome seems to be less pronounced using DSM. As TACE is rather a palliative therapeutic approach, DSM therefore might be more suited. Further studies on TACE of liver metastases should focus on to the patients' quality of life. (orig.) [German] Seit Beginn der 80er Jahre ist die transarterielle Chemoembolisation (TACE) von Lebermetastasen Gegenstand zahlreicher Studien, ohne dass sich bisher ein einheitliches Therapiekonzept

  16. Development of starch-gelatin complex microspheres as sustained release delivery system

    Directory of Open Access Journals (Sweden)

    B N Vedha Hari

    2012-01-01

    Full Text Available The starch was isolated from jackfruit seeds and evaluated for its preformulation properties, like tapped density, bulk density, and particle size. The fourier transform infrared (FTIR analysis was done and compared with that of the commercially available starch which confirmed the properties. Using the various concentrations of jackfruit seed starch, the microspheres were prepared, combining with gelatin by ionotropic gelation technique. The developed microspheres were subjected to analysis of particle size, drug content, entrapment efficiency, and percentage yield. The spectral analysis confirmed the presence of drug and absence of interactions. Scanning electron microscope image showed that the particles were in spherical shape with a rough surface. The in vitro drug release in water for 12 hours proved to be in the range of 89 to 100%. The various kinetic models were applied using release data to confirm the mechanism of drug. It was concluded that the jackfruit starch-gelatin microspheres gave satisfactory results and met pharmacopieal limits.

  17. Seeing is believing, PLGA microsphere degradation revealed in PLGA microsphere/PVA hydrogel composites.

    Science.gov (United States)

    Gu, Bing; Sun, Xuanhao; Papadimitrakopoulos, Fotios; Burgess, Diane J

    2016-04-28

    The aim of this study was to understand the polymer degradation and drug release mechanism from PLGA microspheres embedded in a PVA hydrogel. Two types of microspheres were prepared with different molecular weight PLGA polymers (approximately 25 and 7 kDa) to achieve different drug release profiles, with a 9-day lag phase and without a lag phase, respectively. The kinetics of water uptake into the microspheres coincided with the drug release profiles for both formulations. For the 25 kDa microspheres, minimal water uptake was observed in the early part of the lag phase followed by substantial water uptake at the later stages and in the drug release phase. For the 7 kDa microspheres, water uptake occurred simultaneously with drug release. Water uptake was approximately 2-3 times that of the initial microsphere weight for both formulations. The internal structure of the PLGA microspheres was evaluated using low temperature scanning electron microscopy (cryo-SEM). Burst drug release occurred followed by pore forming from the exterior to the core of both microspheres. A well-defined hydrogel/microsphere interface was observed. For the 25 kDa microspheres, internal pore formation and swelling occurred before the second drug release phase. The surface layer of the microspheres remained intact whereas swelling, and degradation of the core continued throughout the drug release period. In addition, microsphere swelling reduced glucose transport through the coatings in PBS media and this was considered to be a as a consequence of the increased thickness of the coatings. The combination of the swelling and microdialysis results provides a fresh understanding on the competing processes affecting molecular transport of bioanalytes (i.e. glucose) through these composite coatings during prolonged exposure in PBS. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Seeing is believing, PLGA microsphere degradation revealed in PLGA microsphere/PVA hydrogel composites

    OpenAIRE

    Gu, Bing; Sun, Xuanhao; Papadimitrakopoulos, Fotios; Burgess, Diane J.

    2016-01-01

    The aim of this study was to understand the polymer degradation and drug release mechanism from PLGA microspheres embedded in a PVA hydrogel. Two types of microspheres were prepared with different molecular weight PLGA polymers (approximately 25 and 7 kDa) to achieve different drug release profiles, with a 9-day lag phase and without a lag phase, respectively. The kinetics of water uptake into the microspheres coincided with the drug release profiles for both formulations. For the 25 kDa micr...

  19. Degradation of corn starch under the influence of gamma irradiation

    International Nuclear Information System (INIS)

    El Saadany, R.M.A.; El Saadany, F.M.; Foda, Y.H.

    1976-01-01

    Irradiation of corn (maize) starch with different doses of gamma irradiation ranging from 1 x 10 5 rad to 1 x 10 6 rad resulted in the increase of starch acidity and reducing power. Molecular degradation was observed as a result of marked decrease in starch viscosity and intinsic viscosity as well as swelling capacity. The gelatinization time and temperature of the irradiated starch became shorter than in the control sample. Internal changes in the irradiated starch occured as a result of lowering the number of glucose unit per segment in the irradiated starch molecules. All changes were proportional to the doses of gamma irradiation used. (orig.) [de

  20. Evaluation of the degradation of clonidine-loaded PLGA microspheres.

    Science.gov (United States)

    Gaignaux, Amélie; Réeff, Jonathan; De Vriese, Carine; Goole, Jonathan; Amighi, Karim

    2013-01-01

    The release of an encapsulated drug is dependent on diffusion and/or degradation/erosion processes. This work aimed to better understand the degradation mechanism of clonidine-loaded microparticles. Gel permeation chromatography was used to evaluate the degradation of the polymer. The water-uptake and the weight loss were determined gravimetrically. The swelling behaviour and the morphological changes of the formulations were observed by microscopy. The glass transition temperature and the crystallinity were also determined by differential scanning calorimetry and X-ray diffraction, respectively. The pH of the medium and inside the microspheres was assessed. The microspheres captured a large amount of water, allowing a decrease in the molecular weight of the polymer. The pH of the medium decreased after release of the degradation products and the pH inside the microparticles remained constant due to the neutralization of these acidic products. Clonidine and buffers both had an action on the degradation.

  1. Novel syntactic foams made of ceramic hollow micro-spheres and starch: theory, structure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.M.; Kim, H.S. [University of Newcastle, Callaghan, NSW (Australia). Faculty of Engineering & Built Environments

    2007-08-15

    Novel syntactic foams for potential building material applications were developed using starch as binder and ceramic hollow micro-spheres available as waste from coal-fired power stations. Foams of four different micro-sphere size groups were manufactured with either pre- or post-mould gelatinization process. They were of ternary system including voids with a foam density range of approximately 0.33-0.44 g/cc. Compressive failure behaviour and mechanical properties of the manufactured foams were evaluated. Not much difference in failure behaviour or in mechanical properties between the two different processes (pre- and post-mould gels) was found for a given binder content. Compressive failure of all syntactic foams was of shear on plane inclined 45 degrees to compressive loading direction. Failure surfaces of most syntactic foams were characterized by debonded micro-spheres. Compressive strength and modulus of syntactic foams were found to be dependant mainly on binder content but mostly independent of micro-sphere size. Some conditions of relativity arising from properties of constituents leading to the rule of mixtures relationships for compressive strength and to understanding of compressive/transitional failure behaviour were developed. The developed relationships based on the rule of mixtures were partially verified. Some formation of starch webs on failure surfaces was discussed.

  2. Effect of starch microspheres on the passage of labelled erythrocytes and a low molecular weight marker through the liver

    International Nuclear Information System (INIS)

    Starkhammar, H.; Haakansson, L.

    1987-01-01

    Degradable starch microspheres (DSM) injected intra-arterially together with cytostatic drugs increase the regional uptake of the drug and as a result reduce the systemic drug concentration. Previous studies have indicated that fixed doses of DSM result in different degrees of vascular occlusion and therefore variable systemic concentration of the co-injected drug. Continuous registration of the systemic concentration of 99 Tc m -hydroxymethylene diphosphonate ( 99 Tc m -HDP) co-injected intra-arterially with DSM was earlier used to monitor treatment sessions and to optimize the dose of microspheres. Further to investigate the mechanism of DSM-induced retention, the effect of DSM on the passage of this low molecular weight marker and of labelled erythrocytes (a marker confined to the blood vessels), was compared in 10 patients with liver metastases. DSM reduced the amount of 99 Tc m -HDP passing through the liver by 6 to 47% while the amount of erythrocytes eventually passing the liver was much less reduced (0-14%). The rate of passage, however, was significantly reduced for both labelled markers. These results indicate that substances retained by co-injection of DSM are not to a significant extent lodged within the blood vessels but diffuse into extra-vasal tissue compartments. (orig.)

  3. Degradation and Moisture Absorption Study of Potato-starch Linear ...

    African Journals Online (AJOL)

    Composite of linear low density polyethylene (LLDPE) and potato-starch was produced and subjected to degradation studies with the agencies of enzymes, exposure to weather and immersion in water. Enzymatic hydrolysis degraded the matrix to an extent greater than 40% loss in strength and about 20% loss in ...

  4. XRD Investigation of Some Thermal Degraded Starch Based Materials

    Directory of Open Access Journals (Sweden)

    Mihai Todica

    2016-01-01

    Full Text Available The thermal degradation of some starch based materials was investigated using XRD method. The samples were obtained by thermal extrusion of mixtures of different proportions of starch, glycerol, and water. Such materials are suitable for the manufacturing of low pollutant packaging. Thermal degradation is one of the simplest ways to destroy such materials and this process is followed by structural modification of the local ordering of samples, water evaporation, crystallization, oxidation, or destruction of the chemical bonds. These modifications need to be studied in order to reduce to the minimum production of pollutant residues by burning process. XRD measurements show modification of the local ordering of the starch molecules depending on the temperature and initial composition of the samples. The molecular ordering perturbation is more pronounced in samples with low content of starch.

  5. Amylase activity of a starch degrading bacteria isolated from soil ...

    African Journals Online (AJOL)

    Starch degrading bacteria are most important for industries such as food, fermentation, textile and paper. Thus isolating and manipulating pure culture from various waste materials has manifold importance for various biotechnology industries. In the present investigation a bacterial strain was isolated from soil sample ...

  6. Amylase activity of a starch degrading bacteria isolated from soil ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... Starch degrading bacteria are most important for industries such as food, fermentation, textile and paper. ... Microorganism. During the present investigation Bacillus strain was isolated from soil samples collected from different sites receiving kitchen wastes. One gram of soil ..... Cloning and Expression of.

  7. Preparation and characteristic of gelatine/oxidized corn starch and gelatin/corn starch blend microspheres.

    Science.gov (United States)

    Chen, Hui; Shan, Zhi Hua; Woo, Meng Wai; Chen, Xiao Dong

    2017-01-01

    Combinations of gelatin (G) and oxidized corn starch (OCS) were explored as a new microcapsule composite for single droplet spray drying. The blending solutions property, gel time, transparency and viscosity of G/CS (corn starch) and G/OCS blend solutions were compared at different ratios (10:0;9:1;8:2;7:3;6:4;5:5) and concentrations(1%wt; 3%wt; 5%wt). The drying and dissolution behaviors of composite droplet have been studied using the single droplet drying technique. Possible reaction mechanisms in the composite blend were elucidated by SEM and FTIR techniques. Blends solutions of G/OCS showed longer Gel time, higher transparency and lower viscosity; further displayed faster dissolution rate than that of G/CS under similar conditions. This was attributed to the formed Schiff base between the aldehyde group of OCS and amino group of G which improved the compatibility between G and OCS. All results indicated that the composites could be prepared with excellent properties by G/OCS (6:4) which would overcome some disadvantage such as thermodynamic incompatibility and phase separation by G/CS. Copyright © 2016. Published by Elsevier B.V.

  8. ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Jiaqian, E-mail: jiaqian.q@chula.ac.th [Metallurgy and Materials Science Research Institute, Chulalongkorn University, Bangkok 10330 (Thailand); Zhang, Xinyu, E-mail: xyzhang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Yang, Chengwu; Cao, Meng; Ma, Mingzhen; Liu, Riping [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2017-01-15

    Highlights: • ZnO microspheres-rGO nanocomposites were prepared via a solution method. • ZnO microspheres anchored on the rGO sheets is observed using SEM and TEM. • The obtained nanocomposites exhibit good photocatalytic degradation of MB under UV light irradiation. - Abstract: In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h{sup +}) and superoxide radicals (·O{sub 2}{sup −}).

  9. Characteristics of cassava starch fermentation wastewater based on structural degradation of starch granules

    Directory of Open Access Journals (Sweden)

    Juliane Mascarenhas Pereira

    2016-01-01

    Full Text Available ABSTRACT: Sour cassava starch is a naturally modified starch produced by fermentation and sun drying, achieving the property of expansion upon baking. Sour cassava starch' bakery products can be prepared without the addition of yeast and it is gluten free. The fermentation process associated with this product has been well studied, but the wastewater, with high acidity and richness in other organic compounds derived from starch degradation, requires further investigation. In this study, the structure of solids present in this residue was studied, seeking to future applications for new materials. The solids of the wastewater were spray dried with maltodextrin (MD with dextrose equivalent (DE of 5 and 15 and the structure of the powder was evaluated by scanning electron microscopy. A regular structure with a network arrangement was observed for the dried material with MD of 5 DE, in contrast to the original and fermented starches structure, which suggests a regular organization of this new material, to be studied in future applications.

  10. Degradation behavior of theophylline/chitosan/β-cyclodextrin microspheres for pulmonary drug delivery

    Directory of Open Access Journals (Sweden)

    Li Wang

    2016-04-01

    Full Text Available To evaluate the degradation behavior of theophylline/chitosan/β-cyclo-dextrin microspheres, we performed both in vitro study by putting the microspheres in phosphate buffered saline or in phosphate buffer saline with enzyme and in vivo study by implanting the microspheres into the back of male Sprague-Dawley rats. The results showed that microspheres were degraded in enzymatic hydrolysis and phosphate buffer saline, which were degraded faster in 0.2 mg/mL lysozyme than in phosphate buffer saline. The morphology of microspheres in phosphate buffer saline and enzyme solution developed rough surfaces, and showed irregular shape and pores after 8 weeks. The microspheres were degraded in vivo within 8 weeks with irregular, sheet, porous morphology, and the diameters were smaller than 5 μm. These results indicated that the theophylline/chitosan/β-cyclodextrin microspheres had a good degradation both in vitro and in vivo which can be used as a pulmonary drug delivery carrier.

  11. Kinetic modeling and exploratory numerical simulation of chloroplastic starch degradation

    Directory of Open Access Journals (Sweden)

    Nag Ambarish

    2011-06-01

    Full Text Available Abstract Background Higher plants and algae are able to fix atmospheric carbon dioxide through photosynthesis and store this fixed carbon in large quantities as starch, which can be hydrolyzed into sugars serving as feedstock for fermentation to biofuels and precursors. Rational engineering of carbon flow in plant cells requires a greater understanding of how starch breakdown fluxes respond to variations in enzyme concentrations, kinetic parameters, and metabolite concentrations. We have therefore developed and simulated a detailed kinetic ordinary differential equation model of the degradation pathways for starch synthesized in plants and green algae, which to our knowledge is the most complete such model reported to date. Results Simulation with 9 internal metabolites and 8 external metabolites, the concentrations of the latter fixed at reasonable biochemical values, leads to a single reference solution showing β-amylase activity to be the rate-limiting step in carbon flow from starch degradation. Additionally, the response coefficients for stromal glucose to the glucose transporter kcat and KM are substantial, whereas those for cytosolic glucose are not, consistent with a kinetic bottleneck due to transport. Response coefficient norms show stromal maltopentaose and cytosolic glucosylated arabinogalactan to be the most and least globally sensitive metabolites, respectively, and β-amylase kcat and KM for starch to be the kinetic parameters with the largest aggregate effect on metabolite concentrations as a whole. The latter kinetic parameters, together with those for glucose transport, have the greatest effect on stromal glucose, which is a precursor for biofuel synthetic pathways. Exploration of the steady-state solution space with respect to concentrations of 6 external metabolites and 8 dynamic metabolite concentrations show that stromal metabolism is strongly coupled to starch levels, and that transport between compartments serves to

  12. IMPACT INJURY DIAGNOSIS IN MANGO THROUGH STARCH DEGRADATION INDEX

    Directory of Open Access Journals (Sweden)

    FRANCISCO DE ASSIS DE SOUSA

    2017-01-01

    Full Text Available This study aimed to evaluate the use of starch degradation index (SDI in the diagnosis of areas of impact injuries in 'Tommy Atkins' mango, in different maturation stages. The experiment layout was a fully randomized factorial design (5 x 2, represented by five maturation stages and two handlings, with and without impact, with four replicates. SDI was determined through a subjective scale of scores indicating mango pulp darkened areas by reaction with iodine-potassium iodide solution. Subsequently, these scores were correlated with physicochemical quality variables. The results showed no influence of impact on fruit quality, in any of the studied maturation stages. Moreover, soluble solid contents increased throughout maturation stages, regardless of whether the fruits suffered impact or not. As a result, SDI is unsuitable to indicate fruit impact injury. However, there is a good correlation between SDI and pulp color, vitamin C, pH, titratable acidity, soluble solids, SS/ TA ratio and non-reducing sugars.

  13. Genetic manipulation of amylotic yeast for degradation of starch

    International Nuclear Information System (INIS)

    Nasim, A.

    1991-01-01

    The availability of a variety of techniques in Genetic Engineering has greatly facilitated the manipulation of hereditary material. These methodologies provide effective tools to utilize the existing microorganisms for creating novel combinations of hybrid strains for the degradation of substrates that can be converted into alcohol. Yeasts have several distinct advantages including the long standing industrial experience of scaling up the growth. The present report deals with the account of some experimental approaches used to obtained amylolytic yeast strains with ability to degrade starch. From among the naturally occurring yeasts schwanniomyces was found to be very efficient for this purpose. Both gene cloning and protoplast fusion were used to transfer DNA from Saccharomyces diastaticus to the bakers yeast Saccharomyces cerevisiae. The glucoamylase gene of S. diastaticus has been successfully cloned into S. cerevisiae. The observations are discussed as there relate to the current efforts to degrade substrates for energy placing special emphasis on the tremendous potential that naturally occurring microbes may have. This emphasizes the need to examine this aspect critically before initiating attempts to genetically engineer microbes for heterologous gene transfer, which appears to have serious limitations as far as the production of the end products adequate for industrial purposes are concerned. (author)

  14. Advances in Degradable Embolic Microspheres: A State of the Art Review.

    Science.gov (United States)

    Doucet, Jensen; Kiri, Lauren; O'Connell, Kathleen; Kehoe, Sharon; Lewandowski, Robert J; Liu, David M; Abraham, Robert J; Boyd, Daniel

    2018-01-26

    Considerable efforts have been placed on the development of degradable microspheres for use in transarterial embolization indications. Using the guidance of the U.S. Food and Drug Administration (FDA) special controls document for the preclinical evaluation of vascular embolization devices, this review consolidates all relevant data pertaining to novel degradable microsphere technologies for bland embolization into a single reference. This review emphasizes intended use, chemical composition, degradative mechanisms, and pre-clinical safety, efficacy, and performance, while summarizing the key advantages and disadvantages for each degradable technology that is currently under development for transarterial embolization. This review is intended to provide an inclusive reference for clinicians that may facilitate an understanding of clinical and technical concepts related to this field of interventional radiology. For materials scientists, this review highlights innovative devices and current evaluation methodologies (i.e., preclinical models), and is designed to be instructive in the development of innovative/new technologies and evaluation methodologies.

  15. Degradation of starch-poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) bioplastic in tropical coastal waters.

    Science.gov (United States)

    Imam, S H; Gordon, S H; Shogren, R L; Tosteson, T R; Govind, N S; Greene, R V

    1999-02-01

    Extruded bioplastic was prepared from cornstarch or poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV) or blends of cornstarch and PHBV. The blended formulations contained 30 or 50% starch in the presence or absence of polyethylene oxide (PEO), which enhances adherence of starch granules to PHBV. Degradation of these formulations was monitored for 1 year at four stations in coastal water southwest of Puerto Rico. Two stations were within a mangrove stand. The other two were offshore; one of these stations was on a shallow shoulder of a reef, and the other was at a location in deeper water. Microbial enumeration at the four stations revealed considerable flux in the populations over the course of the year. However, in general, the overall population densities were 1 order of magnitude less at the deeper-water station than at the other stations. Starch degraders were 10- to 50-fold more prevalent than PHBV degraders at all of the stations. Accordingly, degradation of the bioplastic, as determined by weight loss and deterioration of tensile properties, correlated with the amount of starch present (100% starch >50% starch > 30% starch > 100% PHBV). Incorporation of PEO into blends slightly retarded the rate of degradation. The rate of loss of starch from the 100% starch samples was about 2%/day, while the rate of loss of PHBV from the 100% PHBV samples was about 0.1%/day. Biphasic weight loss was observed for the starch-PHBV blends at all of the stations. A predictive mathematical model for loss of individual polymers from a 30% starch-70% PHBV formulation was developed and experimentally validated. The model showed that PHBV degradation was delayed 50 days until more than 80% of the starch was consumed and predicted that starch and PHBV in the blend had half-lives of 19 and 158 days, respectively. Consistent with the relatively low microbial populations, bioplastic degradation at the deeper-water station exhibited an initial lag period, after which degradation

  16. Fractional rate of degradation (kd) of starch in the rumen and its ...

    African Journals Online (AJOL)

    Fractional rate of degradation (kd) of fermentable nutrients in the rumen is an important parameter in modern feed evaluation systems based on mechanistic models. Estimates of kd for starch was obtained on 19 starch sources originating from barley, wheat, oat, maize and peas and treated in different ways both chemically ...

  17. Estimation of rate of degradation (Kd) of starch in the rumen and its ...

    African Journals Online (AJOL)

    Torben Hvelplund

    Abstract. Fractional rate of degradation (kd) of fermentable nutrients in the rumen is an important parameter in modern feed evaluation systems based on mechanistic models. Estimates of kd for starch was obtained on 19 starch sources originating from barley, wheat, oat, maize and peas and treated in different ways both.

  18. Modeling macromolecular degradation of corn starch in a twin screw extruder

    NARCIS (Netherlands)

    Einde, van den R.M.; Veen, van der M.E.; Bosman, H.; Goot, van der A.J.; Boom, R.M.

    2005-01-01

    Macromolecular degradation of starch in a twin screw extruder was modeled. A shear cell having well-defined flow conditions described earlier was used to measure peak viscosity of corn starch melts at various moisture contents and temperatures. Shear rate and elongation rate distributions in the

  19. Degradation and Moisture Absorption Study of Potato-starch Linear ...

    African Journals Online (AJOL)

    acer

    More thrust is paid to blending of synthetic polymers with macromolecules such as starch, chitin and chitosan etc(Van Soest and. Kortleve, 1999; Salmoral, et al., 2000; Park et al., 2001). Starch is widely considered a choice filler for this purpose; it is biodegradable, relatively cheap, non toxic and available in many forms(Lim ...

  20. Enzymatic degradation behavior and cytocompatibility of silk fibroin-starch-chitosan conjugate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Baran, Erkan T., E-mail: erkantur@metu.edu.tr; Tuzlakoglu, Kadriye, E-mail: kadriye@dep.uminho.pt; Mano, Joao F., E-mail: jmano@dep.uminho.pt; Reis, Rui L., E-mail: rgreis@dep.uminho.pt

    2012-08-01

    The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in {alpha}-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: Black-Right-Pointing-Pointer Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. Black-Right-Pointing-Pointer The enzymatic biodegradation and the cytocompatibility of conjugates were tested. Black-Right-Pointing-Pointer The conjugate with 30% starch composition was degraded by {alpha}-amylase significantly. Black-Right-Pointing-Pointer Higher starch composition in conjugates prevented protease and lysozyme degradation. Black-Right-Pointing-Pointer Fibroin incorporation effectively increased the cell proliferation of conjugates.

  1. Synthesis of Dandelion—like CuO microspheres for photocatalytic degradation of reactive black-5

    Science.gov (United States)

    Purnachander Rao, Martha; Wu, Jerry J.; Syed, Asad; Ameen, Fuad; Anandan, Sambandam

    2018-01-01

    Dandelion-like CuO microspheres with the size of ∼1–2 μm were synthesized by ultrasound method without any surfactants. The crystallinity, morphology, composition of products and optical properties were characterized by x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectrometer, Fourier transform infrared and UV–vis absorption spectroscopy. The crystal size and optical band gap of CuO nanoparticles were found to be 6.51 nm and 1.70 eV and their photocatalytic ability towards reactive black-5 was analyzed. The observed experimental results revealed that the Dandelion-like CuO microspheres possess good photocatalytic activity i.e., around 76% dye was degraded in 5 h under visible light illumination at room temperature and the degradation follows the pseudo-first order kinetics with a rate constant of 0.312 h‑1. Suitable growth mechanism was also proposed for the formation of Dandelion-like CuO microspheres.

  2. Starch degradation in rumen fluid as influenced by genotype, climatic conditions and maturity stage of maize, grown under controlled conditions

    NARCIS (Netherlands)

    Ali, M.; Cone, J.W.; Hendriks, W.H.; Struik, P.C.

    2014-01-01

    Starch is the major component of maize kernels, contributing significantly to the feeding value of forage maize when fed to ruminants. The effects of genotype, climatic conditions and maturity stage on starch content in the kernels and on in vitro starch degradability in rumen fluid were

  3. Silver nanoparticles: a potential nanocatalyst for the rapid degradation of starch hydrolysis by α-amylase.

    Science.gov (United States)

    Ernest, Vinita; Shiny, P J; Mukherjee, Amitava; Chandrasekaran, N

    2012-05-01

    Silver nanoparticles (AgNPs) are proven to be an effective catalytic material for various applications due to their excellent optical and electronic properties. In this paper, we describe a novel approach for the degradation of starch using the catalytic behaviour of AgNPs in an enzyme catalysed reaction of starch hydrolysis by α-amylase. AgNPs were synthesized by soluble starch reducing silver nitrate to silver atoms. An increase of 4.7-fold in reducing sugar formation and 1.5 times faster enzyme activity confirmed the catalytic activity of AgNPs as a nanocatalyst. Surprisingly, starch degradation tests revealed that 9.9 mg of starch was hydrolysed within 5 min, which corroborates with the reducing sugar assay. In short, the present study paves way for the faster degradation of starch by immobilizing the enzyme onto the surface of the AgNP, which could be a promising application in the food industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Effects of ruminally degradable starch levels on performance, nitrogen balance, and nutrient digestibility in dairy cows fed low corn-based starch diets

    Directory of Open Access Journals (Sweden)

    Guobin Luo

    2017-05-01

    Full Text Available Objective This trial was performed to examine the effects of ruminally degradable starch (RDS levels in total mixed ration (TMR with low corn-based starch on the milk production, whole-tract nutrient digestibility and nitrogen balance in dairy cows. Methods Eight multiparous Holstein cows (body weight [BW]: 717±63 kg; days in milk [DIM]: 169±29 were assigned to a crossover design with two dietary treatments: a diet containing 62.3% ruminally degradable starch (% of total starch, low RDS or 72.1% ruminally degradable starch (% of total starch, high RDS. Changes to the ruminally degradable levels were conducted by using either finely ground corn or steam-flaked corn as the starch component. Results The results showed that dry matter intake, milk yield and composition in dairy cows were not affected by dietary treatments. The concentration of milk urea nitrogen was lower for cows fed high RDS TMR than low RDS TMR. The whole-tract apparent digestibility of neutral detergent fiber, acid detergent fiber and crude protein decreased, and that of starch increased for cows fed high RDS TMR over those fed low RDS TMR, with no dietary effect on the whole-tract apparent digestibility of dry matter and organic matter. The proportion of urinary N excretion in N intake was lower and that of fecal N excretion in N intake was higher for cows fed high RDS TMR than those fed low RDS TMR. The N secretion in milk and the retention of N were not influenced by the dietary treatments. Total purine derivative was similar in cows fed high RDS TMR and low RDS TMR. Consequently, estimated microbial N flow to the duodenum was similar in cows fed high RDS TMR and low RDS TMR. Conclusion Results of this study show that ruminally degradable starch levels can influence whole-tract nutrient digestibility and nitrogen balance in dairy cows fed low corn-based starch diets, with no influence on performance.

  5. Crystal structure of an essential enzyme in seed starch degradation - barley limit dextrinase in complex with cyclodextrins

    DEFF Research Database (Denmark)

    Vester-Christensen, Malene Bech; Abou Hachem, Maher; Svensson, Birte

    2010-01-01

    Barley limit dextrinase [Hordeum vulgare limit dextrinase (HvLD)] catalyzes the hydrolysis of α-1,6 glucosidic linkages in limit dextrins. This activity plays a role in starch degradation during germination and presumably in starch biosynthesis during grain filling. The crystal structures of Hv...... provide new insight into cation sites and the concerted action of the battery of hydrolytic enzymes in starch degradation....

  6. Surface binding sites in amylase have distinct roles in recognition of starch structure motifs and degradation

    DEFF Research Database (Denmark)

    Cockburn, Darrell; Nielsen, Morten M.; Christiansen, Camilla

    2015-01-01

    degrading enzymes and critically important for their function. The affinity towards a variety of starch granules as well as soluble poly- and oligosaccharides of barley alpha-amylase 1 (AMY1) wild-type and mutants of two SBSs (SBS1 and SBS2) was investigated using Langmuir binding analysis, confocal laser...

  7. Unusual Starch Degradation Pathway via Cyclodextrins in the Hyperthermophilic Sulfate-Reducing Archaeon Archaeoglobus fulgidus Strain 7324▿

    Science.gov (United States)

    Labes, Antje; Schönheit, Peter

    2007-01-01

    The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, α-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly β-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway. PMID:17921308

  8. Monodisperse raspberry-like multihollow polymer/Ag nanocomposite microspheres for rapid catalytic degradation of methylene blue.

    Science.gov (United States)

    Tian, Qiong; Yu, Xiaojing; Zhang, Lifeng; Yu, Demei

    2017-04-01

    Raspberry-like multihollow polymer microspheres were prepared by seeded swelling polymerization and decorated with silver nanoparticles (AgNPs) in the presence of polyvinylpyrrolidone (PVP) which acted as both reducing and stabilizing agent. Formation mechanism of the raspberry-like multihollow microsphere was discussed on the basis of water absorption of sulfonated groups in the seeded swelling polymerization. Effects of weight ratio of sodium 4-vinylbenzenesulfonate to styrene (NaSS/St) of the seed particles, the concentration of PVP and [Ag(NH 3 ) 2 ] + ions on the properties of polymer/Ag nanocomposite microspheres were investigated by microscopic observation, nitrogen adsorption/desorption isotherms, UV-vis absorption spectra, X-ray diffraction patterns and thermogravimetric analysis. The results demonstrated that the raspberry-like multihollow microspheres were successfully fabricated by controlling over the NaSS/St of the seed particles in the seeded swelling polymerization by which the fabrication of hollow structure became simple and convenient. The spherical AgNPs were loaded on the polymer microsphere by in-situ chemical reduction due to the stabilization and reduction of PVP and the attraction between sulfonated groups and [Ag(NH 3 ) 2 ] + ions. The raspberry-like multihollow polymer/Ag microspheres showed good catalytic activity and reusability in the degradation of methylene blue in the presence of NaBH 4 . Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Ruminococcus bromii is a keystone species for the degradation of resistant starch in the human colon.

    Science.gov (United States)

    Ze, Xiaolei; Duncan, Sylvia H; Louis, Petra; Flint, Harry J

    2012-08-01

    The release of energy from particulate substrates such as dietary fiber and resistant starch (RS) in the human colon may depend on the presence of specialist primary degraders (or 'keystone species') within the microbial community. We have explored the roles of four dominant amylolytic bacteria found in the human colon in the degradation and utilization of resistant starches. Eubacterium rectale and Bacteroides thetaiotaomicron showed limited ability to utilize RS2- and RS3-resistant starches by comparison with Bifidobacterium adolescentis and Ruminococcus bromii. In co-culture, however, R. bromii proved unique in stimulating RS2 and RS3 utilization by the other three bacterial species, even in a medium that does not permit growth of R. bromii itself. Having previously demonstrated low RS3 fermentation in vivo in two individuals with undetectable populations of R. bromii-related bacteria, we show here that supplementation of mixed fecal bacteria from one of these volunteers with R. bromii, but not with the other three species, greatly enhanced the extent of RS3 fermentation in vitro. This argues strongly that R. bromii has a pivotal role in fermentation of RS3 in the human large intestine, and that variation in the occurrence of this species and its close relatives may be a primary cause of variable energy recovery from this important component of the diet. This work also indicates that R. bromii possesses an exceptional ability to colonize and degrade starch particles when compared with previously studied amylolytic bacteria from the human colon.

  10. Derivation of an Analytical Solution to a Reaction-Diffusion Model for Autocatalytic Degradation and Erosion in Polymer Microspheres.

    Science.gov (United States)

    Ford Versypt, Ashlee N; Arendt, Paul D; Pack, Daniel W; Braatz, Richard D

    2015-01-01

    A mathematical reaction-diffusion model is defined to describe the gradual decomposition of polymer microspheres composed of poly(D,L-lactic-co-glycolic acid) (PLGA) that are used for pharmaceutical drug delivery over extended periods of time. The partial differential equation (PDE) model treats simultaneous first-order generation due to chemical reaction and diffusion of reaction products in spherical geometry to capture the microsphere-size-dependent effects of autocatalysis on PLGA erosion that occurs when the microspheres are exposed to aqueous media such as biological fluids. The model is solved analytically for the concentration of the autocatalytic carboxylic acid end groups of the polymer chains that comprise the microspheres as a function of radial position and time. The analytical solution for the reaction and transport of the autocatalytic chemical species is useful for predicting the conditions under which drug release from PLGA microspheres transitions from diffusion-controlled to erosion-controlled release, for understanding the dynamic coupling between the PLGA degradation and erosion mechanisms, and for designing drug release particles. The model is the first to provide an analytical prediction for the dynamics and spatial heterogeneities of PLGA degradation and erosion within a spherical particle. The analytical solution is applicable to other spherical systems with simultaneous diffusive transport and first-order generation by reaction.

  11. Sustained release of hydrophilic drug from polyphosphazenes/poly(methyl methacrylate) based microspheres and their degradation study.

    Science.gov (United States)

    Akram, Muhammad; Yu, Haojie; Wang, Li; Khalid, Hamad; Abbasi, Nasir M; Zain-ul-Abdin; Chen, Yongsheng; Ren, Fujie; Saleem, Muhammad

    2016-01-01

    Drug delivery system is referred as an approach to deliver the therapeutic agents to the target site safely in order to achieve the maximum therapeutic effects. In this perspective, synthesis of three new polyphosphazenes and their blend fabrication system with poly(methyl methacrylate) is described and characterized with (1)H NMR, (31)P NMR, GPC and DSC. Furthermore, these novel blends were used to fabricate microspheres and evaluated for sustain release of hydrophilic drug (aspirin as model drug). Microspheres of the two blends showed excellent encapsulation efficacy (about 93%), controlled burst release (2.3% to 7.93%) and exhibited sustain in vitro drug release (13.44% to 32.77%) up to 218 h. At physiological conditions, the surface degradation of microspheres and diffusion process controlled the drug release sustainability. Furthermore, it was found that the degree of porosity was increased with degradation and the resulting porous network was responsible for water retention inside the microspheres. The percentage water retention was found to be interrelated with degradation time and percentage drug release. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Microspheres of poly(ε-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    International Nuclear Information System (INIS)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de

    2011-01-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho 2 O 3 . Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  13. Effects of microbial enzymes on starch and hemicellulose degradation in total mixed ration silages

    Directory of Open Access Journals (Sweden)

    Tingting Ning

    2017-02-01

    Full Text Available Objective This study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR silage. Methods The TMRs were prepared with soybean curd residue, alfalfa hay (ATMR or Leymus chinensis hay (LTMR, corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties. Results Both ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens, B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively. Conclusion The microbial amylase contributes to starch hydrolysis during the

  14. Feedback Inhibition of Starch Degradation in Arabidopsis Leaves Mediated by Trehalose 6-Phosphate1[W][OPEN

    Science.gov (United States)

    Martins, Marina Camara Mattos; Hejazi, Mahdi; Fettke, Joerg; Steup, Martin; Feil, Regina; Krause, Ursula; Arrivault, Stéphanie; Vosloh, Daniel; Figueroa, Carlos María; Ivakov, Alexander; Yadav, Umesh Prasad; Piques, Maria; Metzner, Daniela; Stitt, Mark; Lunn, John Edward

    2013-01-01

    Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by β-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 µm in the cytosol, 0.2 to 0.5 µm in the chloroplasts, and 0.05 µm in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night. PMID:24043444

  15. Fractional rate of degradation (kd) of starch in the rumen and its relation to in vivo rumen and total digestibility

    DEFF Research Database (Denmark)

    Hvelplund, Torben; Larsen, Mogens; Lund, Peter

    2009-01-01

    was a series of cross-over experiments with two cows and two periods. Ruminal starch pool was estimated from rumen evacuation and starch flow was estimated by duodenal and faeces sampling. Fractional rate of rumen degradation was estimated from the equation [kd = rumen degraded/rumen pool] and rumen and total...... digestibility of starch from flow measurements. The relation between kd and rumen digestibility (RD) was estimated to [kd = 1.139 -3.580*RD + 3.078*RD2; R2 = 0.45; valid for 0.580.81]. It is concluded that the relations between kd and starch digestibility can be used to estimate kd for feed table use from...

  16. The cold storage of green bananas affects the starch degradation during ripening at higher temperature.

    Science.gov (United States)

    Peroni-Okita, Fernanda H G; Cardoso, Mateus B; Agopian, Roberta G D; Louro, Ricardo P; Nascimento, João R O; Purgatto, Eduardo; Tavares, Maria I B; Lajolo, Franco M; Cordenunsi, Beatriz R

    2013-07-01

    The aim of this work was to investigate the starch degradation of bananas stored at low temperature (13°C, cold-stored group) and bananas stored at 19°C (control group) during ripening. The starch granules were isolated during different stages of banana ripening, and their structure was investigated using different techniques. The activities of α-amylase and β-amylase associated to the starch granules were determined, and their presence was confirmed using immunolocalization assays. The increased molecular mobility likely facilitated the intake and action of α-amylase on the granule surface, where it was the prevalent enzyme in bananas stored at low temperature. The 10 days of storage at low temperature also influenced the sizes and shapes of the granules, with a predominance of rounded granules and pits on the surface along with superior amylose content, the higher amounts of amylopectin A-chains and the subtle increase in the A-type allomorph content. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Gas production and starch degradability of corn and barley meals differing in mean particle size.

    Science.gov (United States)

    Gallo, A; Giuberti, G; Masoero, F

    2016-06-01

    The objective of this study was to verify the effect of mean particle size (mPS) on both gas production and in vitro rumen starch degradability (IVSD) of corn and barley meals (Cm and Bm, respectively). Batches of the same Cm or Bm were separately processed through 2 different mills (i.e., a cutter mill or a rotor speed mill) equipped with or without different screens to achieve different mPS for each tested meal. Samples were analyzed accordingly to a completely randomized design and the main tested effect of model was mPS (n=11, from 0.46 to 3.50mm mPS for Cm or n=10, from 0.11 to 2.98mm mPS for Bm). For both in vitro assays, the rumen inocula were collected from 2 rumen-fistulated Holstein lactating dairy cows fed a total mixed ration with 16.2% crude protein, 28.5% starch, and 35.0% neutral detergent fiber on a dry matter basis. To fit gas production data, 1-pool exponential model and 1-pool or 2-pool Gompertz models were adopted. The rate of gas production decreased and lag increased by increasing mPS of both Cm and Bm, irrespective of adopted 1-pool models. When the 2-pool Gompertz model was used to fit gas production data, a shift of particles from fast to slow fermentable pools was measured by increasing mPS. In particular, the ratio between fast and slow final volumes ranged from 0.90 at 0.11mm mPS to 0.10 at 2.98mm mPS for Bm. For Cm, the ratio between fast and slow final volumes decreased quadratically by increasing mPS, with the highest value (i.e., 0.58) measured at the lowest tested mPS. Values lower than 0.10 were measured for mPS greater than 1.93mm for Cm. Concerning IVSD data, linear decreases in rate of starch degradation equal to -0.049 or -0.092h(-1) for each 1-mm increase in mPS were achieved for Cm and Bm, respectively. The 7-h IVSD decreased by 6.3 or 6.5% starch for each 1-mm increase in mPS of Cm or Bm, respectively. Present findings supported the hypothesis that different particle sizes within the same starch source represent an important

  18. Popcorn balls-like ZnFe{sub 2}O{sub 4}-ZrO{sub 2} microsphere for photocatalytic degradation of 2,4-dinitrophenol

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xi [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Liu, Yutang [Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Xia, Xinnian, E-mail: xnxia@hnu.edu.cn [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Wang, Longlu [College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China)

    2017-06-15

    Highlights: • Popcorn balls-like microsphere photocatalyst. • High photocatalytic activity toward 2,4-DNP degradation. • Degradation kinetics, mechanism, active species were analyzed. • Excellent stable recycling performance. - Abstract: In this paper, novel popcorn balls-like ZnFe{sub 2}O{sub 4}-ZrO{sub 2} composite microspheres were successfully fabricated by a simple hydrothermal method. The morphology, structure and optical property of the microspheres were characterized. The microspheres were used as the photocatalysts to degrade 2,4-dinitrophenol, and exhibited superior photocatalytic performance. Under simulated solar visible light irradiation, the degradation rate of ZnFe{sub 2}O{sub 4}-ZrO{sub 2} photocatalyst (mass ratio of ZnFe{sub 2}O{sub 4}/ZrO{sub 2} = 2:1) was almost 7.4 and 2.4 times higher than those of pure ZnFe{sub 2}O{sub 4} and ZrO{sub 2}. The enhancement could attribute to stronger light absorption, lower carrier recombination and multi-porous structure of the microspheres. Moreover, the popcorn balls-like photocatalysts can be easily separated, because of the magnetism of the samples. After five times runs, the photocatalyst still showed 90% of its photocatalytic degradation efficiency. This work demonstrated a good prospect for removing organic pollutants in water.

  19. Biochemical characterization and bioinformatic analysis of two large multi-domain enzymes from Microbacterium aurum B8.A involved in native starch degradation

    NARCIS (Netherlands)

    Valk, Vincent

    2017-01-01

    Microbacterium aurum B8.A is a unique bacterium with the ability to degrade starch granules through pore formation. In this study two enzymes (MaAmyA and MaAmyB) which are involved in granular starch degradation and were specific for the M. aurum B8.A strain, have been characterized in detail. Both

  20. Compostability of Co-Extruded Starch/Poly(Lactic Acid) Polymeric Material Degradation in an Activated Inert Solid Medium

    Science.gov (United States)

    Copinet, Alain; Legin-Copinet, Estelle; Erre, Damien

    2009-01-01

    The aim of this work was to estimate the biodegradation of a co-extruded starch/poly(lactic acid) polymeric material using a vermiculite based inert solid medium which could simulate compost medium and enable us to achieve complete carbon balances. At the end of the test the mineralisation rate was compared to those obtained for co-extruded starch/poly(lactic acid) polymeric material degradation in compost. It was shown that the mineralisation rate after 45 days of degradation was similar in activated vermiculite medium to the one in compost. A protocol for both extraction and quantification of the carbon included in the different degradation by-products was proposed and the carbon balance of the polymer degradation was followed during the test with a satisfactory accuracy. As the non-degraded PLA and starch material had been retrieved during the test, the evolution of the glass transition temperature and the molecular weight of PLA could be followed. A two-step degradation mechanism was highlighted in inert solid medium, showing the fundamental role of abiotic reactions for PLA degradation in compost.

  1. CeO2/Bi2WO6Heterostructured Microsphere with Excellent Visible-light-driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

    Science.gov (United States)

    Zhang, Fengjun; Zou, Shuang; Wang, Tianye; Shi, Yuxi; Liu, Peng

    2017-10-01

    CeO 2 /Bi 2 WO 6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO 2 /Bi 2 WO 6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi 2 WO 6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible-light irradiation. The 1CeO 2 /2Bi 2 WO 6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO 2 and Bi 2 WO 6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO 2 could significantly enhance the photocatalytic activity of CeO 2 /Bi 2 WO 6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO 2 /Bi 2 WO 6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory. © 2017 The American Society of Photobiology.

  2. Thermal degradation of biopolymer binders: the example of starch-poly(acrylic acid

    Directory of Open Access Journals (Sweden)

    B. Grabowska

    2010-01-01

    Full Text Available To characterise a polymer, it is of fundamental importance to determine its parameters, like the temperatures of destruction, vitrification, melting point, specific mass losses or polymorphic transformations, which frequently determine the quality of the product and its applications. Thermal analyses were conducted of samples of a biopolymer binder: a starch-poly(acrylic acid composition and a moulding sand with a biopolymer binder previously hardened with microwaves. In order to determine the thermal stability of the examined samples by determining the destruction temperature and the thermal effects of transformations taking place during heating, FTIR spectroscopy and thermal analysis (DSC, DTG, TG methods were used. In addition, volatile products of degradation were analysed using the thermogravimetry (TG method coupled online with mass spectrometry (MS. These examinations were also aimed at identifying the changes that can take place in the moulding sand when it comes into contact with liquid metal.

  3. Starch-enhanced degradation of HMW PAHs by Fusarium sp. in an aged polluted soil from a coal mining area.

    Science.gov (United States)

    Zhao, Ou-Ya; Zhang, Xue-Na; Feng, Sheng-Dong; Zhang, Li-Xiu; Shi, Wei; Yang, Zhi-Xin; Chen, Miao-Miao; Fang, Xue-Dan

    2017-05-01

    The present study used strain ZH-H2 (Fusarium sp.) isolated by our group as the PAH-degrading strain and 5-6-rings PAHs as degradation objects. The soil incubation experiment was carried out to investigate the starch-enhanced degradation effects of HMW PAHs by Fusarium sp. in an Aged Polluted Soil from a Coal Mining Area. The results showed that the removal rates of BaP, InP and BghiP increased with increasing inoculation rate of ZH-H2 in the unsterile aged polluted soil of coal mining area, with the exception of BbF degradation which increased in the H2 treatment and then decreased. Different addition dosage of starch apparently resulted in degradation of 4 PAHs in soil, with removal rates of 14.47% for BaP, 23.83% for DbA, 30.77% for BghiP and 31.00% for InP obtained with treatment D2, respectively higher than in treatment D1. So starch addition apparently enhanced the degradation of the 4 PAHs, especially InP and BghiP, by native microbes in the aged HMW PAH-polluted soil. By adding starch to these aged polluted soils with inoculated strain ZH-H2, HMW-PAHs degradation was further improved and addition of 0.5 g kg -1 starch to soils with 1.0 g kg -1 Fusarium ZH-H2 (D 2  + H 2 ) performed best to the 4 HMW-PAHs in all of these combination treatments by a factor of up to 3.09, depending on the PAH. We found that the highest polyphenol oxidase activities under D 2  + H 2 treatments are consistent with the results of removal rates of 4 PAHs. Our findings suggest that the combination of Fusarium sp. ZH-H2 and starch offers a suitable alternative for bioremediation of aged PAH-contaminated soil in coal mining areas, with a recommended inoculation size of 0.5 g Fusarium sp. ZH-H2 and addition of 0.5 g kg -1 starch per kg soil. Copyright © 2016. Published by Elsevier Ltd.

  4. Self-assembly of polyoxometalate-thionine multilayer films on magnetic microspheres as photocatalyst for methyl orange degradation under visible light irradiation.

    Science.gov (United States)

    Li, Hongfang; Gao, Shuiying; Cao, Minna; Cao, Rong

    2013-03-15

    (PW(12)-TH)(n) multilayer films (PW(12)=PW(12)O(40)(3-), TH=thionine) were deposited successfully on core-shell structured Fe(3)O(4)@SiO(2) magnetic microspheres through layer-by-layer (LbL) self-assembly method. The physical and photocatalytic properties of such magnetic microspheres coated with (PW(12)-TH)(n) films have been characterized by SEM, FTIR, and UV-vis spectra. The microspheres exhibit better photocatalytic activity toward the degradation of methyl orange (MO) under visible light irradiation than the quartz slides support. In addition, the use of magnetic support guarantees facile, clean, fast, and efficient separation of the photocatalyst after the degradation of MO. Such catalysts can be reused several times and display good reproducibility by magnetic separation. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Comparative activity of TiO{sub 2} microspheres and P25 powder for organic degradation: Implicative importance of structural defects and organic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chuan [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); Liu, Hong, E-mail: liuhong@cigit.ac.cn [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); Liu, Yuan [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 401122 (China); He, Guang’an [School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Jiang, Chengchun [School of Civil and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055 (China)

    2014-11-15

    Highlights: • Adsorption of TiO{sub 2} microspheres was stronger than P25, while less active. • P25 was more active owing to its oxygen vacancy and Ti(III). • Difference in the adsorption abilities of TiO{sub 2} microspheres varied kinetic models. - Abstract: TiO{sub 2} microspheres have been employed as a promisingly new photocatalyst for water and wastewater treatment. P25 TiO{sub 2} is commonly employed and its properties are well established as photocatalyst. In this study, photocatalytic activities of the two TiO{sub 2} samples are compared by degrading sulfosalicylic acid (SSA), phenol, and 2,4-Dichlorophenoxyacetic acid (2,4-D) under 365 nm UV illumination in a suspension system at neutral pH and associated optimized TiO{sub 2} dosages. The results showed that the three organic compounds unexceptionally degraded more rapidly on P25 than on TiO{sub 2} microspheres in terms of the concentration–time curves and total organic carbon removals at 120 min. This might me attributed the presence of oxygen vacancies and Ti(III) defects already present on P25 as determined by electron paramagnetic resonance, implying that the defects played an important role for the enhancement of the charge transfer step as rate-determining step. The degradations of three organic compounds on P25 and TiO{sub 2} microspheres could be well described by the first-order rate equation, while the degradation kinetics of SSA on TiO{sub 2} microspheres was quite different. The difference was ascribed to the medium adsorption ability of SSA on the TiO{sub 2} surface.

  6. Novel Bioengineered Cassava Expressing an Archaeal Starch Degradation System and a Bacterial ADP-Glucose Pyrophosphorylase for Starch Self-Digestibility and Yield Increase

    Directory of Open Access Journals (Sweden)

    Ayalew Ligaba-Osena

    2018-02-01

    Full Text Available To address national and global low-carbon fuel targets, there is great interest in alternative plant species such as cassava (Manihot esculenta, which are high-yielding, resilient, and are easily converted to fuels using the existing technology. In this study the genes encoding hyperthermophilic archaeal starch-hydrolyzing enzymes, α-amylase and amylopullulanase from Pyrococcus furiosus and glucoamylase from Sulfolobus solfataricus, together with the gene encoding a modified ADP-glucose pyrophosphorylase (glgC from Escherichia coli, were simultaneously expressed in cassava roots to enhance starch accumulation and its subsequent hydrolysis to sugar. A total of 13 multigene expressing transgenic lines were generated and characterized phenotypically and genotypically. Gene expression analysis using quantitative RT-PCR showed that the microbial genes are expressed in the transgenic roots. Multigene-expressing transgenic lines produced up to 60% more storage root yield than the non-transgenic control, likely due to glgC expression. Total protein extracted from the transgenic roots showed up to 10-fold higher starch-degrading activity in vitro than the protein extracted from the non-transgenic control. Interestingly, transgenic tubers released threefold more glucose than the non-transgenic control when incubated at 85°C for 21-h without exogenous application of thermostable enzymes, suggesting that the archaeal enzymes produced in planta maintain their activity and thermostability.

  7. Degradation pattern of porous CaCO3 and hydroxyapatite microspheres in vitro and in vivo for potential application in bone tissue engineering.

    Science.gov (United States)

    Zhong, Qiwei; Li, Wenhua; Su, Xiuping; Li, Geng; Zhou, Ying; Kundu, Subhas C; Yao, Juming; Cai, Yurong

    2016-07-01

    Despite superior clinical handling, excellent biocompatibility, biodegradation property of calcium phosphate needs to be improved to coincide with the rate of new bone formation. In this study, spherical CaCO3 are fabricated in the presence of the silk sericin and then transformed into porous hydroxyapatite (HAP) microspheres via hydrothermal method. The degradation behavior of obtained CaCO3, HAP and their mixture is first investigated in vitro. The result demonstrates that the weight loss of HAP microspheres are almost 24.3% after immersing in pH 7.40 Tris-HCl buffer solution for 12 weeks, which is far slower than that of spherical CaCO3 (97.5%). The degradation speed of the mixtures depends on the proportion of CaCO3 and HAP. The mixture with higher content of CaCO3 possesses a quicker degradation speed. The obtained CaCO3 and HAP microspheres are injected into subcutaneous tissue of ICR mice with the assistance of sodium alginate. The result in vivo also shows an obvious difference of degradation speed between the obtained CaCO3 and HAP microspheres, implying it is feasible to modulate the degradation property of the mixture through changing the proportion of CaCO3 and HAP The good cytocompatibility of the two kinds of microspheres is proved and a mild inflammation response is observed only at early stage of implantation. The job offers a simple method to modify the degradation properties of biomaterial for potential use in bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Polymeric microspheres

    Science.gov (United States)

    Walt, David R.; Mandal, Tarun K.; Fleming, Michael S.

    2004-04-13

    The invention features core-shell microsphere compositions, hollow polymeric microspheres, and methods for making the microspheres. The microspheres are characterized as having a polymeric shell with consistent shell thickness.

  9. Effect of conventional and extrusion pelleting on in situ ruminal degradability of starch, protein, and fibre in cattle

    DEFF Research Database (Denmark)

    Razzaghi, Ali; Larsen, Mogens; Lund, Peter

    2016-01-01

    +50% sugar beet pulp (SBP), or 50% maize+50% SBP. Meals were pelleted by either conventional pelleting, or by cooking extrusion using two distinct settings giving pellets with either high density (HD) or low density (LD). Ruminal degradation of starch, crude protein (CP) and NDF, and intestinal......>Pelleting>Meal). In contradiction, ESD for pure wheat and wheat mixtures was reduced, though differences were minor. Conventional pelleting reduced the effective protein degradability (EPD) for pure wheat, but extrusion did not further affect the EPD. In contrast, the most intense processing with extrusion LD increased EPD...

  10. Thermal degradation process of poly (alpha-methylstyrene) microspheres coated with glow discharge polymer

    International Nuclear Information System (INIS)

    Zhang Zhanwen; Huang Yong; Tang Yongjian; Li Bo; Chen Sufen; He Zhibing

    2009-01-01

    Glow discharge polymer (GDP) shell was made by the decomposable mandrel technique using poly(alpha-methylstyrene) (PAMS) mandrel. The PAMS degradation rate and the GDP shell surface morphology at different equilibrium temperatures were investigated. Degradation rate was calculated from weight variation of PAMS before and after pyrolysis process. Experiment results indicate that the degradation rate decreases at the fixed equilibrium temperature and graded temperature can improve the rate. The degradation process has an effect on the GDP shell properties. The PAMS doesn't molten to flow liquid during degradation. But the degradation can reduce surface finish of GDP coatings. The GDP shell deffects are the result of the PAMS degradiation process. (authors)

  11. Data of thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid as crosslinking agent.

    Science.gov (United States)

    González Seligra, Paula; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-06-01

    Interest in biodegradable edible films as packaging or coating has increased because their beneficial effects on foods. In particular, food products are highly dependents on thermal stability, integrity and transition process temperatures of the packaging. The present work describes a complete data of the thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid (CA) as crosslinking agent described in the article titled: "Biodegradable and non-retrogradable eco-films based on starch-glycerol with citric acid as crosslinking agent" González Seligra et al. (2016) [1]. Data describes thermogravimetric and dynamical mechanical experiences and provides the figures of weight loss and loss tangent of the films as a function of the temperature.

  12. Effect of α-Amylase Degradation on Physicochemical Properties of Pre-High Hydrostatic Pressure-Treated Potato Starch

    Science.gov (United States)

    Mu, Tai-Hua; Zhang, Miao; Raad, Leyla; Sun, Hong-Nan; Wang, Cheng

    2015-01-01

    The effect of high hydrostatic pressure (HHP) on the susceptibility of potato starch (25%, w/v) suspended in water to degradation by exposure to bacterial α-amylase (0.02%, 0.04% and 0.06%, w/v) for 40 min at 25°C was investigated. Significant differences (p starch (PS) exposed to α-amylase (0.06%, w/v) showed a significantly greater degree of hydrolysis and amount of reducing sugar released compared to α-amylase at a concentration of 0.04% (w/v) or 0.02% (w/v). Native PS (NPS) granules have a spherical and elliptical form with a smooth surface, whereas the hydrolyzed NPS (hNPS) and hydrolyzed HHP-treated PS granules showed irregular and ruptured forms with several cracks and holes on the surface. Hydrolysis of HHP-treated PS by α-amylase could decrease the average granule size significantly (p starch in both the ordered and the amorphous structure, especially in hydrolyzed HHP600 PS. The B-type of hydrolyzed HHP600 PS with α-amylase at a concentration 0.06% (w/v) changed to a B+V type with an additional peak at 2θ = 19.36°. The HHP600 starch with 0.06% (w/v) α-amylase displayed the lowest value of T o (onset temperature), T c (conclusion temperature) and ΔH gel (enthalpies of gelatinization). These results indicate the pre-HHP treatment of NPS leads to increased susceptibility of the granules to enzymatic degradation and eventually changes of both the amorphous and the crystalline structures. PMID:26642044

  13. Amylase inhibits Neisseria gonorrhoeae by degrading starch in the growth medium.

    OpenAIRE

    Gregory, M R; Gregory, W W; Bruns, D E; Zakowski, J J

    1983-01-01

    Highly purified salivary alpha-amylase inhibited the growth of fresh isolates of Neisseria gonorrhoeae on GC agar base medium supplemented with 2% IsoVitaleX (BBL Microbiology Systems). Hydrolysis of starch in the medium by amylase resulted in a negative starch-iodine test. However, purified amylase did not inhibit gonococcal growth on agar plates that contained hemoglobin (chocolate agar). This effect was not caused by inhibition of amylase, since amylase activity was the same in the presenc...

  14. Proteomic approach reveals that starch degradation contributes to anthocyanin accumulation in tuberous root of purple sweet potato.

    Science.gov (United States)

    Wang, Shaoqing; Pan, Dezhuo; Lv, Xiaojie; Song, Xiaomin; Qiu, Zhimin; Huang, Chunmei; Huang, Ronghui; Chen, Wei

    2016-06-30

    A comparative proteomic approach was carried out to investigate anthocyanin biosynthesis in the tuberous roots of yellow sweet potato (YSP) and purple sweet potato (PSP) cultivars. More than 800 proteins were reproducibly detected through two-dimensional electrophoresis (2-DE), of which 50 proteins with 39 more and 11 less accumulated in PSP were identified through matrix-assisted laser desorption ionization-time of flight/time of flight mass spectrometry (MALDI-TOF/TOF-MS). Most of the analyzed proteins are annotated to be involved in starch metabolism and glycolysis. The more abundant starch phosphorylase (SP) and phosphoglucomutase (PGM) in PSP promoted the synthesis of precursors for anthocyanin synthesis. The results implied that starch degradation provided abundant substrates for anthocyanin biosynthesis in tuberous roots of PSP. 24kDa vacuolar protein (VP24) is related to anthocyanin transport and accumulation in vacuoles. Vacuole-associated annexin protein, VCaB42, is correlated with tonoplast biogenesis. Synergistic action of the two proteins is probably involved in the microautophagy and the intravacuolar trapping of anthocyanins. Interestingly, both VCaB42 and VP24 were more accumulated in PSP, suggesting that anthocyanins generated in the cytosol were transported into and became stored in the vacuoles of PSP. The present study provides new insights into the mechanism of tuberous root-specific anthocyanin accumulation in PSP. Sweet potato ranks as the seventh most important crop worldwide. Purple sweet potato, a special sweet potato cultivar, has been extensively investigated because large amounts of anthocyanin accumulate in its tuberous roots. Anthocyanin is well known for its free radical-scavenging activity and beneficial effects on human health. Its biosynthetic pathway has been well characterized in model plants. Although large-scale systematic studies have been performed to identify the proteins present in sweet potato, information on the

  15. Postruminal degradation of crude protein, neutral detergent fibre and starch of maize and grass silages in dairy cows

    DEFF Research Database (Denmark)

    Ali, M.; Weisbjerg, Martin Riis; Cone, J.W.

    2012-01-01

    The Dutch feed evaluation system for ruminants uses assumptions and regression equations to estimate the intestinal digestibility of crude protein (CP), neutral detergent fibre (NDF) and starch. These assumptions and equations are based on many different studies, obtained over a very long period....... and Protein System; CP, crude protein; DM, dry matter; DRUP, intestinal digestion of rumen undegraded feed protein; Fim, Feed into Milk system; NDF, neutral detergent fibre; RUP, rumen undegraded protein; SD, standard deviation; TMR, total mixed ration......The Dutch feed evaluation system for ruminants uses assumptions and regression equations to estimate the intestinal digestibility of crude protein (CP), neutral detergent fibre (NDF) and starch. These assumptions and equations are based on many different studies, obtained over a very long period....... The objective of this study was to develop a unique dataset on the ruminal degradability and the postruminal digestibility of CP, NDF (aNDFom, amylase neutral detergent fibre organic matter basis) and starch in maize and grass silages, using the mobile nylon bag technique. Twenty samples of maize silage and 20...

  16. Degradation of the starch components amylopectin and amylose by barley α-amylase 1: Role of surface binding site 2

    DEFF Research Database (Denmark)

    Nielsen, Jonas Willum; Kramhøft, Birte; Bozonnet, Sophie

    2012-01-01

    Barley α-amylase isozyme 1 (AMY1, EC 3.2.1.1) contains two surface binding sites, SBS1 and SBS2, involved in the degradation of starch granules. The distinct role of SBS1 and SBS2 remains to be fully understood. Mutational analysis of Tyr-380 situated at SBS2 previously revealed that Tyr-380...... is required for binding of the amylose helix mimic, β-cyclodextrin. Also, mutant enzymes altered at position 380 displayed reduced binding to starch granules. Similarly, binding of wild type AMY1 to starch granules was suppressed in the presence of β-cyclodextrin. We investigated the role of SBS2 by comparing...... kinetic properties of the wild type AMY1 and the Y380A mutant enzyme in hydrolysis of amylopectin, amylose and β-limit dextrin, and the inhibition by β-cyclodextrin. Progress curves of the release of reducing ends revealed a bi-exponential hydrolysis of amylopectin and β-limit dextrin, whereas hydrolysis...

  17. Amylase inhibits Neisseria gonorrhoeae by degrading starch in the growth medium.

    Science.gov (United States)

    Gregory, M R; Gregory, W W; Bruns, D E; Zakowski, J J

    1983-12-01

    Highly purified salivary alpha-amylase inhibited the growth of fresh isolates of Neisseria gonorrhoeae on GC agar base medium supplemented with 2% IsoVitaleX (BBL Microbiology Systems). Hydrolysis of starch in the medium by amylase resulted in a negative starch-iodine test. However, purified amylase did not inhibit gonococcal growth on agar plates that contained hemoglobin (chocolate agar). This effect was not caused by inhibition of amylase, since amylase activity was the same in the presence or absence of blood products. Moreover, survival of N. gonorrhoeae in buffered saline was not affected by amylase. These results suggest that amylase inhibited the growth of N. gonorrhoeae on GC agar base plates by hydrolyzing starch.

  18. Photo-producible and photo-degradable starch/TiO2bionanocomposite as a food packaging material: Development and characterization.

    Science.gov (United States)

    Goudarzi, Vahid; Shahabi-Ghahfarrokhi, Iman

    2018-01-01

    In current study, starch/TiO 2 bionanocomposites were produced by photochemical reactions as a biodegradable food packaging material. Physical, mechanical, thermal and water-vapor permeability properties were investigated. Then, the photo-degradation properties of nanocomposite films were studied. This is the first report of the photo-producible and photo-degradable bionanocomposite as a food packaging material. Film-forming solutions were exposed to ultraviolet A (UV-A) for different times. Our results showed that UV-A irradiation increased the hydrophobicity of starch films. With increasing UV-A exposure time, tensile strength and Young's modulus of the specimens were decreased. On the other hand, elongation at break of the films was increased with increasing UV-A irradiation. The glass transition temperature and melting point of the films were increased by increasing UV-A exposure time. Nevertheless, the results showed that photo-degradation properties of photo-produced starch/TiO 2 nanocomposite were significantly higher than virgin starch and virgin starch/TiO 2 films. According to obtain results and bibliography a schema was developed to describe the mechanism of photo-production and photo-degradation of starch/TiO 2 by UV-A ray. It can be concluded, the modification of starch based biopolymer by UV-A and nano-TiO 2 , is an easy and accessible process to improve the packaging properties and photo-degradability of biopolymer based films. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Introduction of enzymatically degradable poly(trimethylene carbonate) microspheres into an injectable calcium phosphate cement

    NARCIS (Netherlands)

    Habraken, Wouter J. E. M.; Zhang, Zheng; Wolke, Joop G. C.; Grijpma, Dirk W.; Mikos, Antonios G.; Feijen, Jan; Jansen, John A.

    Poly(trimethylene carbonate) (PTMC) is an enzymatically degradable polyester with rubber-like properties. Introduction of this polymer into an injectable calcium phosphate bone cement can therefore be used to introduce macroporosity into the cement for tissue engineering purposes as well as to

  20. A comparison of factors involved in starch degradation in barley germination under laboratory and malting conditions

    Science.gov (United States)

    Grains of the malting barley cultivar Legacy were laboratory germinated (LG) or micromalted (MM) and sampled daily from 0 to 5 days after imbibition/steeping. Alpha-amylase and beta-amylase activities and protein levels along with starch, osmolyte concentration (OC), and sugar (glucose, sucrose, fr...

  1. The synthesis conditions, characterizations and thermal degradation studies of an etherified starch from an unconventional source

    International Nuclear Information System (INIS)

    Lawal, O.S.; Lechner, M.D.; Kulicke, W.M.

    2008-05-01

    Starch isolated from an under-utilized legume plant (pigeon pea) was carboxymethylated. Influences of reaction parameters were investigated on the degree of substitution (DS) and the reaction efficiency (RE). Studies showed that optimal DS of 1.12 could be reached at reaction efficiency of 80.6 % in isopropanol-water reaction medium (40 deg. C, 3h). The scanning electron microscopy showed that after carboxymethylation, the granular appearance of the native starch was distorted. Wide-angle X-ray diffractometry revealed that crystallinity was reduced significantly after carboxymethylation. The infrared spectra revealed new bands in the carboxymethyl starch at ν =1600, 1426 and 1324 cm -1 and they were attributed to carbonyl functional groups vibration, -CH2 scissoring and OH bending vibration respectively. Broad band 13 C NMR of carboxymethyl starch showed intense peak at δ 180.3 ppm and it was assigned for carbonyl carbon on the carboxymethyl substituent on the AGU (Anhydroglucose Unit). DEPT (Distortionless Enhancement by Polarization Transfer) 135 NMR showed negative signals which correspond to methylene carbons on the AGU. The differential scanning calorimetry (DSC) suggests loss of crystallinity after carboxymethylation. Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) show that thermal stability improved after carboxymethylation. The study provides information on the preparation and characterization of a biomaterial from a new source which could be used alone or in the preparation of other functional polymers for diverse polymer applications. (author)

  2. Comparative investigation on a hexane-degrading strain with different cell surface hydrophobicities mediated by starch and chitosan.

    Science.gov (United States)

    Chen, Dong-Zhi; Jiang, Ning-Xin; Ye, Jie-Xu; Cheng, Zhuo-Wei; Zhang, Shi-Han; Chen, Jian-Meng

    2017-05-01

    Bioremediation usually exhibits low removal efficiency toward hexane because of poor water solubility, which limits the mass transfer rate between the substrate and microorganism. This work aimed to enhance the hexane degradation rate by increasing cell surface hydrophobicity (CSH) of the degrader, Pseudomonas mendocina NX-1. The CSH of P. mendocina NX-1 was manipulated by treatment with starch and chitosan solution of varied concentrations, reaching a maximum hydrophobicity of 52%. The biodegradation of hexane conformed to the Haldane inhibition model, and the maximum degradation rate (ν max ) of the cells with 52% CSH was 0.72 mg (mg cell) -1 ·h -1 in comparison with 0.47 mg (mg cell) -1 ·h -1 for cells with 15% CSH. The production of CO 2 by high CSH cells was threefold higher than that by cells at 15% CSH within 30 h, and the cumulative rates of O 2 consumption were 0.16 and 0.05 mL/h, respectively. High CSH was related to low negative charge carried by the cell surface and probably reduced the repulsive electrostatic interactions between hexane and microorganisms. The FT-IR spectra of cell envelopes demonstrated that the methyl chain was inversely proportional to increasing CSH values, but proteins exhibited a positive effect to CSH enhancement. The ratio of extracellular proteins and polysaccharides increased from 0.87 to 3.78 when the cells were treated with starch and chitosan, indicating their possible roles in increased CSH.

  3. Three-dimensional MnO2porous hollow microspheres for enhanced activity as ozonation catalysts in degradation of bisphenol A.

    Science.gov (United States)

    Tan, Xiuqin; Wan, Yifeng; Huang, Yajing; He, Chun; Zhang, Zaili; He, Zhuoyan; Hu, Lingling; Zeng, Jiawei; Shu, Dong

    2017-01-05

    Three-dimensional (3D) MnO 2 porous hollow microspheres (δ- and α- MnO 2 PHMSs), with high adsorption and catalytic ozonation performance, were synthesized by a self-template (MnCO 3 microspheres) process at room temperature. The synthesized MnO 2 PHMSs were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area. The results showed that PHMSs exhibit the excellent adsorption ability and catalytic activity owning to their hollow spherical structure, mesoporous shell and well-defined interior voids, leading to the strong adsorption for bisphenol A (BPA) and the retention of O 3 molecules on catalyst. Moreover, the catalytic performance of α-MnO 2 PHMSs was better than that of δ-MnO 2 PHMSs which was attributed to the richer lattice oxygen of α-MnO 2 PHMSs to accelerate O 3 decomposition by producing more reactive oxidative species. The degradation efficiency of BPA using 3D α-MnO 2 PHMSs was more than 90% in the presence of ozone within 30min reaction time. The probe tests for reactive oxidative species (ROSs) displayed that BPA degradation by catalytic ozonation is dominated by O 2 - and OH in our present study. Furthermore, the organic compounds as intermediates of the degradation process were identified by LC/MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Estimation of the in situ degradation of the washout fraction of starch by using a modified in situ protocol and in vitro measurements

    NARCIS (Netherlands)

    Jonge, de L.H.; Laar, van H.; Dijkstra, J.

    2015-01-01

    The in situ degradation of the washout fraction of starch in six feed ingredients (i.e. barley, faba beans, maize, oats, peas and wheat) was studied by using a modified in situ protocol and in vitro measurements. In comparison with the washing machine method, the modified protocol comprises a milder

  5. Characteristics of raw starch degrading alpha-amylase from Bacillus aquimaris MKSC 6.2 associated with soft coral Sinularia sp.

    NARCIS (Netherlands)

    Puspasari, Fernita; Nurachman, Zeily; Noer, Achmad Saefuddin; Radjasa, Ocky Karna; van der Maarel, Marc J. E. C.; Natalia, Dessy

    Partially purified alpha-amylase from Bacillus aquimaris MKSC 6.2, a bacterium isolated from a soft coral Sinularia sp., Merak Kecil Island, West Java, Indonesia, showed an ability to degrade raw corn, rice, sago, cassava, and potato starches with adsorption percentage in the range of 65-93%. Corn

  6. Characterisation and enzymic degradation of non-starch polysccharides in lignocellulosic by-products : a study on sunflower meal and palm-kernel meal

    NARCIS (Netherlands)

    Duesterhoeft, E.M.

    1993-01-01

    Non-starch polysaccharides (NSP) constitute a potentially valuable part of plant by- products deriving from the food and agricultural industries. Their use for various applications (fuel, feed, food) requires the degradation and modification of the complex plant materials. This can be

  7. Site and extent of starch degradation in the dairy cow - a comparison between in vivo, in situ and in vitro measurements.

    NARCIS (Netherlands)

    Hindle, V.A.; Vuuren, van A.M.; Klop, A.; Mathijssen-Kamman, A.A.; Gelder, van A.H.; Cone, J.W.

    2005-01-01

    Prediction of the supply of glycogenic precursors to dairy cows and the site of degradation of wheat, maize and potato starch (PS) were determined in an in vivo experiment and the results were compared with data obtained from experiments involving in situ nylon bag and in vitro gas production

  8. Synthesis of core-shell TiO2@g-C3N4 hollow microspheres for efficient photocatalytic degradation of rhodamine B under visible light

    Science.gov (United States)

    Ma, Lina; Wang, Guohong; Jiang, Chuanjia; Bao, Helin; Xu, Qingchuan

    2018-02-01

    Core-shell composites with titanium dioxide (TiO2) hollow microsphere as the core and graphitic carbon nitride (g-C3N4) as the shell were fabricated via a two-step self-assembly procedure with the assistance of ultrasonic dispersion. The as-prepared composite samples with different g-C3N4 contents (0-20%) were thoroughly characterized and the photocatalytic activity was evaluated by the photocatalytic degradation of Rhodamine B (RhB) in aqueous solution under visible light. A g-C3N4 layer of approximately 80 nm was successfully coated on the surface of TiO2 hollow microspheres with a diameter of 1-3 μm, forming a heterostructure with close interfacial contact. The TiO2@g-C3N4 composite exhibited significantly enhanced photocatalytic activity as compared with pure TiO2 hollow microspheres. At an optimum weight ratio of g-C3N4 to TiO2 (15 wt.%), the photocatalytic activity of the composite sample was almost 3 times higher than that of reference TiO2 hollow microspheres. Moreover, the results of recycling test indicated that the TiO2@g-C3N4 composite had excellent stability. A possible photocatalytic reaction mechanism of TiO2@g-C3N4 composite was proposed, in which superoxide radical anions played the major role in the oxidation of RhB, and the separation of photogenerated charge carriers across the heterostructure interface inhibited electron-hole recombination, thus enhancing the photocatalytic activity.

  9. Effect of reprocessing cycles on the degradation of PP/PBAT-thermoplastic starch blends.

    Science.gov (United States)

    Oliveira, Thainá A; Oliveira, Rosimery R; Barbosa, Renata; Azevedo, Joyce B; Alves, Tatianny S

    2017-07-15

    The solid waste management problems caused by the accumulation of plastics require measures to mitigate the environmental damage, and mechanical recycling of plastics is among the possible solutions. In this context, the present study aimed to evaluate the effects of mechanical recycling on the properties of a polypropylene/poly(butylene adipate co-terephthalate)-thermoplastic starch blend (PP/PBAT-Thermoplastic starch blend) when it was subjected to seven reprocessing cycles by a single-screw extruder. The observations by infrared spectroscopy indicated that the chemical structures of the blend and the polypropylene matrix did not present significant changes with the reprocessing cycles. The X-ray diffraction analyses showed that the PP crystals were most affected when reprocessed in their pure form. The observations by thermogravimetry and differential scanning calorimetry indicated that the thermal stability of the blend was higher than that of polypropylene during the extrusion cycles. The scanning electron microscopy images indicated a weak interfacial interaction between the components of the blend, and the mechanical properties showed that the reprocessing improved the elasticity modulus and yield stress, with a consequential decrease of the impact strength. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Starch Bioengineering in Barley

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana

    Starch represents the most important carbohydrate used for food and feed purposes. Increasingly, it is also used as a renewable raw material, as a source of biofuel, and for many different industrial applications. Progress in understanding starch biosynthesis, and investigations of the genes...... involved in this process, has enabled the genetic modification f crops in a rational manner to produce novel designer starches with improved functionality. The hypothesis of the present study is that the hyper-phosphorylation of cereal endosperm starch makes it easily accessible and degradable...... by the amylolytic enzymes while the amylose-only endosperm starch exhibits high resistance to degradation and hence less available for degradation. With the aim to investigate the hypothesis, starch molecular structures were modulated with the above mentioned modifications and were studied for the effects...

  11. Microwave-assisted solvothermal synthesis of flower-like Ag/AgBr/BiOBr microspheres and their high efficient photocatalytic degradation for p-nitrophenol

    International Nuclear Information System (INIS)

    Li, Tingting; Luo, Shenglian; Yang, Lixia

    2013-01-01

    Flower-like Ag/AgBr/BiOBr microspheres were successfully fabricated by the approach of microwave-assisted solvothermal and in situ photo-assisted reduction. A reactive ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C 16 mim]Br) was employed as Br source in the presence of surfactant polyvinylpyrrolidone (PVP). The photocatalytic activity of Ag/AgBr/BiOBr towards the decomposition of p-nitrophenol under visible light irradiation was evaluated. The results indicated that Ag/AgBr/BiOBr showed enhanced photocatalytic activity towards p-nitrophenol, comparing with P25, BiOBr and Ag/AgBr. More than 96% of p-nitrophenol was decomposed in 3.5 h under visible-light irradation. The excellent photocatalytic activity of flower-like Ag/AgBr/BiOBr microspheres can be attributed to the large specific surface area, strong visible-light absorption, suitable energy band structure and surface plasmon resonance effect of Ag nanoparticles. The possible photocatalytic mechanism was proposed based on the active species test and band gap structure analysis. - Graphical abstract: The photocatalytic reaction mechanisms of the as-prepared Ag/AgBr/BiOBr. Display Omitted - Highlights: • Successful synthesis of flower-like Ag/AgBr/BiOBr microspheres. • The Ag/AgBr/BiOBr showed much higher photocatalytic activity towards p-nitrophenol as compared to BiOBr and Ag/AgBr. • The reasons for the excellent photocatalytic activity are the large specific surface area, strong visible-light absorption and surface plasmon resonance effect of Ag nanoparticles. • The O 2 · − , Br 0 and photogenerated h + play key roles in the photocatalytic degradation process

  12. In situ grown hierarchical 50%BiOCl/BiOI hollow flowerlike microspheres on reduced graphene oxide nanosheets for enhanced visible-light photocatalytic degradation of rhodamine B

    Science.gov (United States)

    Su, Xiangde; Yang, Jinjin; Yu, Xiang; Zhu, Yi; Zhang, Yuanming

    2018-03-01

    50%BiOCl/BiOI/reduced graphene oxide (50%BiOCl/BiOI/rGO) composite photocatalyst was synthesized successfully by a facile one-step solvothermal route in this work. Reduction of graphene oxide (GO) took place in the process of solvothermal reaction and a new Bi-C bond between rGO and 50%BiOCl/BiOI was formed. The introduction of rGO affected the morphology of 50%BiOCl/BiOI, resulting in the transformation of 50%BiOCl/BiOI from solid microspheres to hollow microspheres. Both the introduction of rGO and formation of 50%BiOCl/BiOI hollow microspheres can facilitate the light absorption. The strong interaction between 50%BiOCl/BiOI and rGO and the electrical conductivity of rGO greatly improved the effective separation of photogenerated carriers. Hence, GOB-5 demonstrated the highest photocatalytic activity which was over twice of the pristine 50%BiOCl/BiOI in the presence of visible light. Mechanism study revealed that 50%BiOCl/BiOI generated electrons and holes in the presence of visible light, and holes together with rad O2- generated from reduction of O2 by electrons degraded the pollutant directly. Overall, this work provides an excellent reference to the synthesis of chemically bonded BiOX/BiOY (X, Y = Cl, Br, I)/rGO nanocomposite and helps to promote their applications in environmental protection and photoelectric conversion.

  13. Halophilic starch degrading bacteria isolated from Sambhar Lake, India, as potential anode catalyst in microbial fuel cell: A promising process for saline water treatment.

    Science.gov (United States)

    Vijay, Ankisha; Arora, Shivam; Gupta, Sandeep; Chhabra, Meenu

    2018-05-01

    In this study, Microbial Fuel Cell (MFC) capable of treating saline starch water was developed. Sodium chloride (NaCl) concentrations ranging from 500 mM to 3000 mM were tested at the anode. Nitrate was used as an electron acceptor at the biocathode. The halophilic bacteria were isolated from Sambhar Lake, India. Results indicated successful removal of starch (1.83 kg/m 3 -d) and nitrate (0.13 kg/m 3 -d NO 3 - -N) with concomitant power output of 207.05 mW/m 2 at 1000 mM NaCl concentration. An increase in power density from 71.06 mW/m 2 to 207.05 mW/m 2 (2.92 folds) was observed when NaCl concentration was increased from 500 mM to 1000 mM. A decline in power density was observed when the salt concentrations >1000 mM were used. Concentration of 3000 mM supported power output as well as the highest starch degradation (3.2 kg/m 3 -d) and amylase activity of 2.26 IU/ml. The halophilic exoelectrogens were isolated and identified. The present study demonstrates the utility of MFC for degrading starch in saline water. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Three-dimensional MnO{sub 2} porous hollow microspheres for enhanced activity as ozonation catalysts in degradation of bisphenol A

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xiuqin; Wan, Yifeng; Huang, Yajing [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275 (China); He, Chun, E-mail: hechun@mail.sysu.edu.cn [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275 (China); Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510275 (China); Zhang, Zaili; He, Zhuoyan; Hu, Lingling; Zeng, Jiawei [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275 (China); Shu, Dong, E-mail: dshu@scnu.edu.cn [Key Lab of Technology on Electrochemical Energy Storage and Power Generation in Guangdong Universities, School of Chemistry and Environment, South China Normal University, Guangzhou, 510006 (China)

    2017-01-05

    Highlights: • 3D MnO{sub 2} porous hollow microspheres (PHMSs) are prepared by a self-template process. • MnO{sub 2} PHMSs with excellent adsorption and catalytic ozonation performance for BPA. • MnO{sub 2} PHMSs show enhanced activity due to hollow-mesoporous shell spherical structure. • O{sub 2}{sup −} and ·OH are reactive species to induce effective catalytic ozonation of BPA. - Abstract: Three-dimensional (3D) MnO{sub 2} porous hollow microspheres (δ- and α- MnO{sub 2} PHMSs), with high adsorption and catalytic ozonation performance, were synthesized by a self-template (MnCO{sub 3} microspheres) process at room temperature. The synthesized MnO{sub 2} PHMSs were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area. The results showed that PHMSs exhibit the excellent adsorption ability and catalytic activity owning to their hollow spherical structure, mesoporous shell and well-defined interior voids, leading to the strong adsorption for bisphenol A (BPA) and the retention of O{sub 3} molecules on catalyst. Moreover, the catalytic performance of α-MnO{sub 2} PHMSs was better than that of δ-MnO{sub 2} PHMSs which was attributed to the richer lattice oxygen of α-MnO{sub 2} PHMSs to accelerate O{sub 3} decomposition by producing more reactive oxidative species. The degradation efficiency of BPA using 3D α-MnO{sub 2} PHMSs was more than 90% in the presence of ozone within 30 min reaction time. The probe tests for reactive oxidative species (ROSs) displayed that BPA degradation by catalytic ozonation is dominated by ·O{sub 2}{sup −} and ·OH in our present study. Furthermore, the organic compounds as intermediates of the degradation process were identified by LC/MS.

  15. Prediction of CP and starch concentrations in ruminal in situ studies and ruminal degradation of cereal grains using NIRS.

    Science.gov (United States)

    Krieg, J; Koenzen, E; Seifried, N; Steingass, H; Schenkel, H; Rodehutscord, M

    2018-03-01

    Ruminal in situ incubations are widely used to assess the nutritional value of feedstuffs for ruminants. In in situ methods, feed samples are ruminally incubated in indigestible bags over a predefined timespan and the disappearance of nutrients from the bags is recorded. To describe the degradation of specific nutrients, information on the concentration of feed samples and undegraded feed after in situ incubation ('bag residues') is needed. For cereal and pea grains, CP and starch (ST) analyses are of interest. The numerous analyses of residues following ruminal incubation contribute greatly to the substantial investments in labour and money, and faster methods would be beneficial. Therefore, calibrations were developed to estimate CP and ST concentrations in grains and bag residues following in situ incubations by using their near-infrared spectra recorded from 680 to 2500 nm. The samples comprised rye, triticale, barley, wheat, and maize grains (20 genotypes each), and 15 durum wheat and 13 pea grains. In addition, residues after ruminal incubation were included (at least from four samples per species for various incubation times). To establish CP and ST calibrations, 620 and 610 samples (grains and bag residues after incubation, respectively) were chemically analysed for their CP and ST concentration. Calibrations using wavelengths from 1250 to 2450 nm and the first derivative of the spectra produced the best results (R 2 Validation=0.99 for CP and ST; standard error of prediction=0.47 and 2.10% DM for CP and ST, respectively). Hence, CP and ST concentration in cereal grains and peas and their bag residues could be predicted with high precision by NIRS for use in in situ studies. No differences were found between the effective ruminal degradation calculated from NIRS estimations and those calculated from chemical analyses (P>0.70). Calibrations were also calculated to predict ruminal degradation kinetics of cereal grains from the spectra of ground grains

  16. EFFECT OF DIETARY SUPPLEMENTATION OF NON-STARCH POLYSACCHARIDE DEGRADING ENZYMES ON GROWTH PERFORMANCE OF BROILER CHICKS

    Directory of Open Access Journals (Sweden)

    M. A. Nadeem, M. I. Anjum, A. G. Khan and A. Azim

    2005-10-01

    Full Text Available An experiment was conducted to study the performance and carcass parameters of broilers chicks fed diets with and without supplementing non-starch polysaccharide degrading enzymes (NSPDE at the rate of 0.5 g/kg diet. A total of 300 day-old broiler chicks were randomly divided into 12 sets (replicates each comprising 25 chicks and three sets per treatment group, reared on deep litter from 1-42 days post-hatch. Group A was fed diets without NSPDE supplementation, while group B was fed diets supplemented with NSPDE (0.5 g/kg. Group C was fed diets containing 50 kcal/kg less metabolizable energy (ME without NSPDE and group D was fed diets having 50 kcal/kg less ME with NSPDE (0.5 g/kg supplementation. Feed and water were provided ad libitum. Feed intake and feed conversion ratio (FCR from 1-28 days and 1-42 days was significantly (p<0.05 improved in chicks fed NSPDE supplemented diets (groups B and D compared to non-supplemented diets (groups A and C. However, during 29-42 days of growing period enzymes supplementation did not influence feed intake and FCR. Body weight gain, dressing percentage and relative weights of heart, gizzard and shank at 42 days of age was found to be non-significantly different among all groups. However, liver weight reduced significantly (p<0.05 in NSPDE supplemented groups. The study suggested that NSPDE supplementation was beneficial in enhancing feed utilization during the starter phase, while its effects on weight gain, dressing percentage and weights of organs, except liver weight, were found to be non-significant.

  17. The Sucrose Analog Palatinose Leads to a Stimulation of Sucrose Degradation and Starch Synthesis When Supplied to Discs of Growing Potato Tubers1

    Science.gov (United States)

    Fernie, Alisdair R.; Roessner, Ute; Geigenberger, Peter

    2001-01-01

    In the present paper we investigated the effect of the sucrose (Suc) analog palatinose on potato (Solanum tuberosum) tuber metabolism. In freshly cut discs of growing potato tubers, addition of 5 mm palatinose altered the metabolism of exogenously supplied [U-14C]Suc. There was slight inhibition of the rate of 14C-Suc uptake, a 1.5-fold increase in the rate at which 14C-Suc was subsequently metabolized, and a shift in the allocation of the metabolized label in favor of starch synthesis. The sum result of these changes was a 2-fold increase in the absolute rate of starch synthesis. The increased rate of starch synthesis was accompanied by a 3-fold increase in inorganic pyrophosphate, a 2-fold increase in UDP, decreased UTP/UDP, ATP/ADP, and ATP/AMP ratios, and decreased adenylate energy charge, whereas glycolytic and Krebs cycle intermediates were unchanged. In addition, feeding palatinose to potato discs also stimulated the metabolism of exogenous 14C-glucose in favor of starch synthesis. In vitro studies revealed that palatinose is not metabolized by Suc synthases or invertases within potato tuber extracts. Enzyme kinetics revealed different effects of palatinose on Suc synthase and invertase activities, implicating palatinose as an allosteric effector leading to an inhibition of Suc synthase and (surprisingly) to an activation of invertase in vitro. However, measurement of tissue palatinose levels revealed that these were too low to have significant effects on Suc degrading activities in vivo. These results suggest that supplying palatinose to potato tubers represents a novel way to increase starch synthesis. PMID:11299376

  18. Review: microspheres for radioembolization therapy

    International Nuclear Information System (INIS)

    Zhao Mingqiang; Xu Shuhe

    2007-12-01

    Radioembolization of liver cancer has been proven to be an effective therapy in nuclear medicine. The yttrium-90 glass microspheres has been used to treat both primary and metastatic liver tumors in clinic which shown encouraging results. The preparation, stability, degradation and application for medical purpose of radioactive microspheres are reviewed. At first, the theory of radioem- bolization treating cancer is discussed; and then three major radiolabled micro- sphere materials are expounded: viz. glass, resin-based and polymer-based; Future improvements in the preparation and use of radioactive microspheres are prospected at last. (authors)

  19. Starch Bioengineering in Barley

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana

    of modified starches (in comparison to wild-type) during grain germination, development and on its pathogen resistance during Fusarium Head blight (FHB). The targets were the phosphate content, which has potential industrial applications and amylose content having valuable food and feed applications...... starch deposition in these lines in combination with suppressed hydrolase activities led to temporal and compensating redirection of starch, sugar and protein metabolism in order to maintain the metabolic dynamics during germination. Further investigations on grain development revealed the differences...... of these modified starches and the modifications on germination and it was observed that HP did not show higher starch mobilization or degradation (despite of lower hydrolase activities), while AO showed significantly lower starch mobilization compared to wild-type (WT). This study oncluded that the inadequate...

  20. Starch-entrapped microsphere fibers improve bowel habit but do not exhibit prebiotic capacity in those with unsatisfactory bowel habits: a phase I, randomized, double-blind, controlled human trial.

    Science.gov (United States)

    Rasmussen, Heather E; Hamaker, Bruce; Rajan, Kumar B; Mutlu, Ece; Green, Stefan J; Brown, Michael; Kaur, Amandeep; Keshavarzian, Ali

    2017-08-01

    Approximately one-third of individuals in the United States experience unsatisfactory bowel habits, and dietary intake, especially one low in fiber, could be partly responsible. We hypothesized that intake of a fermentable fiber (starch-entrapped microspheres, SM) that has a delayed, slow fermentation profile in vitro would improve bowel habit while exhibiting prebiotic capacity in those with self-described unsatisfactory bowel habits, all with minimal adverse effects. A total of 43 healthy volunteers completed a 3-month, double-blind, parallel-arm randomized clinical trial to assess the ability of a daily dose (9 or 12 g) of SM vs psyllium (12 g) to improve bowel habit, including stool consistency and frequency, and modify gut milieu through changes in stool microbiota and short-chain fatty acids while remaining tolerable through minimal gastrointestinal symptoms. All outcomes were compared before and after fiber treatment. Stool frequency significantly improved (P=.0003) in all groups after 3 months, but stool consistency improved only in both SM groups compared with psyllium. In addition, all groups self-reported a similar improvement in overall bowel habit with fiber intake. Both SM and psyllium resulted in minimal changes in microbiota composition and short-chain fatty acid concentrations. The present study suggests that supplementation with a delayed and slow-fermenting fiber in vitro may improve bowel habit in those with constipation, but further investigation is warranted to determine capacity to alter microbiota and fermentation profiles in humans. This trial was registered at ClinicalTrials.gov as NCT01210625. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. High surface area starch products as filler-binder in direct compression tablets

    NARCIS (Netherlands)

    te Wierik, G.HP; Ramaker, J.S; Eissens, A.C; Bergsma, J; Arends-Scholte, A.W.; Lerk, C.F

    Amylodextrin and modified starch products were prepared from amylose-free starches and from (amylose containing) potato starch by enzymatic degradation, followed by precipitation and filtration. The intermediate retrograded starch products were dehydrated by drying at room temperature or washing

  2. Short communication: The effect of an exogenous enzyme with amylolytic activity on gas production and in vitro rumen starch degradability of small and large particles of corn or barley meals.

    Science.gov (United States)

    Gallo, A; Giuberti, G; Duval, S; Moschini, M; Masoero, F

    2016-05-01

    The objective of this study was to evaluate the effect of exogenous amylase supplementation on gas production and on in vitro rumen starch degradability (IVSD) of different sized particles of corn and barley meals (Cm and Bm, respectively). An aqueous liquid amylase formulation from Bacillus licheniformis was tested at 3 enzyme doses (EnzD; 0, 300 and 1,500 kilo novo units/kg of dry matter) on small (starch degradation was greater for small than for large particles of Bm, being 0.187 and 0.125 1/h, respectively. Conversely, the rate of starch degradation of Cm averaged 0.063 1/h and was similar among treatments. Enzyme supplementation tended to reduce lag time and to increase rate of fermentation for both PS of Cm and Bm, with a more pronounced effect for small PS. A limited EnzD effect was measured for IVSD data and rate of starch degradation; PS influenced fermentation parameters and the magnitude of starch degradation more than EnzD. Supplementation with exogenous amylase influenced the rumen fermentation pattern of small and large PS of Cm and Bm, even if the effect of the enzyme supplementation differed according to the PS of cereal meals. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Enhanced production of raw starch degrading enzyme using agro-industrial waste mixtures by thermotolerant Rhizopus microsporus for raw cassava chip saccharification in ethanol production.

    Science.gov (United States)

    Trakarnpaiboon, Srisakul; Srisuk, Nantana; Piyachomkwan, Kuakoon; Sakai, Kenji; Kitpreechavanich, Vichien

    2017-09-14

    In the present study, solid-state fermentation for the production of raw starch degrading enzyme was investigated by thermotolerant Rhizopus microsporus TISTR 3531 using a combination of agro-industrial wastes as substrates. The obtained crude enzyme was applied for hydrolysis of raw cassava starch and chips at low temperature and subjected to nonsterile ethanol production using raw cassava chips. The agro-industrial waste ratio was optimized using a simplex axial mixture design. The results showed that the substrate mixture consisting of rice bran:corncob:cassava bagasse at 8 g:10 g:2 g yielded the highest enzyme production of 201.6 U/g dry solid. The optimized condition for solid-state fermentation was found as 65% initial moisture content, 35°C, initial pH of 6.0, and 5 × 10 6 spores/mL inoculum, which gave the highest enzyme activity of 389.5 U/g dry solid. The enzyme showed high efficiency on saccharification of raw cassava starch and chips with synergistic activities of commercial α-amylase at 50°C, which promotes low-temperature bioethanol production. A high ethanol concentration of 102.2 g/L with 78% fermentation efficiency was achieved from modified simultaneous saccharification and fermentation using cofermentation of the enzymatic hydrolysate of 300 g raw cassava chips/L with cane molasses.

  4. Intracellular degradation of microspheres based on cross-linked dextran hydrogels or amphiphilic block copolymers: a comparative raman microscopy study.

    NARCIS (Netherlands)

    van Manen, H.J.; van Apeldoorn, Aart A.; Verrijk, Ruud; van Blitterswijk, Clemens; Otto, Cornelis

    2007-01-01

    Micro- and nanospheres composed of biodegradable polymers show promise as versatile devices for the controlled delivery of biopharmaceuticals. Whereas important properties such as drug release profiles, biocompatibility, and (bio)degradability have been determined for many types of biodegradable

  5. Variations in polyethylene glycol brands and their influence on the preparation process of hydrogel microspheres

    DEFF Research Database (Denmark)

    Wöhl-Bruhn, Stefanie; Bertz, Andreas; Kuntsche, Judith

    2013-01-01

    the distribution of incorporated drugs between the aqueous phases. For the preparation of hydrogel microspheres based on hydroxyethyl starch-hydroxyethyl methacrylate (HES-HEMA), hydroxyethyl starch-methacrylate (HES-MA), and hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)6MA), polyethylene glycol...

  6. Starch poisoning

    Science.gov (United States)

    Cooking starch poisoning; Laundry starch poisoning ... Cooking and laundry starch are both made from vegetable products, most commonly: Corn Potatoes Rice Wheat Both are usually considered nonpoisonous (nontoxic), but ...

  7. PLGA/alginate composite microspheres for hydrophilic protein delivery

    International Nuclear Information System (INIS)

    Zhai, Peng; Chen, X.B.; Schreyer, David J.

    2015-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility

  8. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  9. Reinforcement Effect of Alkali-Hydrolyzed Wheat Gluten and Shear-Degraded Wheat Starch in Carboxylated Styrene-Butadiene Composites

    Science.gov (United States)

    Wheat gluten (WG) and wheat starch (WS) are the protein and carbohydrate obtained from wheat flours. Wheat gluten is not water soluble or dispersible due to its hydrophobic nature. To prepare wheat gluten dispersions, an alkali hydrolysis reaction was carried out to produce a stable aqueous disper...

  10. Repression of a novel isoform of disproportionating enzyme (stDPE2) in potato leads to inhibition of starch degradation in leaves but not tubers stored at low temperature

    DEFF Research Database (Denmark)

    Lloyd, J.R.; Blennow, A.; Burhenne, K.

    2004-01-01

    A potato (Solanum tuberosum) cDNA encoding an isoform of disproportionating enzyme (stDPE2) was identified in a functional screen in Escherichia coli. The stDPE2 protein was demonstrated to be present in chloroplasts and to accumulate at times of active starch degradation in potato leaves...... and tubers. Transgenic potato plants were made in which its presence was almost completely eliminated. It could be demonstrated that starch degradation was repressed in leaves of the transgenic plants but that cold-induced sweetening was not affected in tubers stored at 4degreesC. No evidence could be found...... for an effect of repression of stDPE2 on starch synthesis. The malto-oligosaccharide content of leaves from the transgenic plants was assessed. It was found that the amounts of malto-oligosaccharides increased in all plants during the dark period and that the transgenic lines accumulated up to 10-fold more than...

  11. Facile fabrication of porous ZnO microspheres by thermal treatment of ZnS microspheres.

    Science.gov (United States)

    Wu, Xiao; Li, KunWei; Wang, Hao

    2010-02-15

    Porous ZnO microspheres with an average size of around 500 nm had been synthesized by thermal treatment of ZnS microspheres in an air atmosphere. The ZnS spheres had been synthesized at a low temperature of 100 degrees C by using L-cysteine (an ordinary amino acid) as a sulfur source with the assist of gelatin. By combining the results of X-ray diffraction (XRD), transmission electron microscope (TEM), field-emission scanning electron microscopy (FE-SEM), and Fourier transformation infrared spectra (FTIR), a structural and morphological characterization of the products was performed. The photocatalytic activity of ZnS microspheres and porous ZnO microspheres have been tested by degradation of Rhodamine-B (RB) under UV light, indicating that the porous ZnO microspheres showed enhanced photocatalytic performance compared to ZnS microspheres and commercial Degussa P25 TiO(2).

  12. The effect of dietary faba bean and non-starch polysaccharide degrading enzymes on the growth performance and gut physiology of young turkeys.

    Science.gov (United States)

    Mikulski, D; Juskiewicz, J; Przybylska-Gornowicz, B; Sosnowska, E; Slominski, B A; Jankowski, J; Zdunczyk, Z

    2017-12-01

    The aim of this study was to investigate the effect of dietary replacement of soya bean meal (SBM) with faba bean (FB) and a blend of non-starch polysaccharide (NSP) degrading enzymes on the gastrointestinal function, growth performance and welfare of young turkeys (1 to 56 days of age). An experiment with a 2×2 factorial design was performed to compare the efficacy of four diets: a SBM-based diet and a diet containing FB, with and without enzyme supplementation (C, FB, CE and FBE, respectively). In comparison with groups C, higher dry matter content and lower viscosity of the small intestinal digesta were noted in groups FB. The content of short-chain fatty acids (SCFAs) in the small intestinal digesta was higher in groups FB, but SCFA concentrations in the caecal digesta were comparable in groups C and FB. In comparison with control groups, similar BW gains, higher feed conversion ratio (FCR), higher dry matter content of excreta and milder symptoms of footpad dermatitis (FPD) were noted in groups FB. Enzyme supplementation increased the concentrations of acetate, butyrate and total SCFAs, but it did not increase the SCFA pool in the caecal digesta. The enzymatic preparation significantly improved FCR, reduced excreta hydration and the severity of FPD in turkeys. It can be concluded that in comparison with the SBM-based diet, the diet containing 30% of FB enables to achieve comparable BW gains accompanied by lower feed efficiency during the first 8 weeks of rearing. Non-starch polysaccharide-degrading enzymes can be used to improve the nutritional value of diets for young turkeys, but more desirable results of enzyme supplementation were noted in the SBM-based diet than in the FB-based diet.

  13. Starch bioengineering

    DEFF Research Database (Denmark)

    Blennow, Andreas

    2018-01-01

    Application of starch in industry frequently requires extensive modification. This is usually achieved by chemical and/or physical modification that is time-consuming and often expensive and polluting. To impart functionality as early as possible in the starch production chain, modification can...... be achieved directly as part of the developing starch storage roots, tubers, and seeds and grains of the crop. Starch has been a strong driver for human development and is now the most important energy provider in the diet forcing the development of novel and valuable starch qualities for specific...... applications. Among the most important structures that can be targeted include starch phosphorylation chain transfer/branching generating chemically substituted and chain length-modified starches such as resistant and health-promoting high-amylose starch. Starch bioengineering has been employed for more than...

  14. Highly Efficient visible-light-induced photoactivity of magnetically retrievable Fe3O4@SiO2@Bi2WO6@g-C3N4 hierarchical microspheres for the degradation of organic pollutant and production of hydrogen

    Science.gov (United States)

    Lu, Dingze; Wang, Hongmei; Shen, Qingqing; Kondamareddy, Kiran Kumar; Neena D

    2017-07-01

    The new multifunctional composite Fe3O4@SiO2@Bi2WO6@g-C3N4 (FSBG) hierarchical microspheres with Bi2WO6/g-C3N4 heterostructure as an outer shell and Fe3O4@SiO2 as a magnetic core have been synthesized and characterized for photocatalytic applications. An efficient and adoptable approach of synthesizing magnetic Bi2WO6/g-C3N4 hierarchical microspheres of grape-like morphology is realized. The as-synthesized structures exhibit highly efficient visible-light absorption and separation efficiency of photo-induced charge. The visible-light-induced photocatalytic activity of g-C3N4, Fe3O4@SiO2@Bi2WO6, and FSBG is evaluated by investigating the photodegradation of Rhodamine B (RhB) and hydrogen (H2) out of water. The comparative study reveals that the FSBG microspheres exhibit an optimum visible-light-induced photocatalytic activity in degrading Rhodamin B (RhB), which is 3.06 and 1.92 times to that of g-C3N4 and Fe3O4@SiO2@Bi2WO6 systems respectively and 3.89 and 2.31 times in the production of hydrogen (H2) out of water, respectively. The FSBG composite microspheres also exhibit good magnetic recoverability. An alternate mechanism for the enhanced visible-light photocatalytic activity is given in the present manuscript.

  15. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

    Full Text Available The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate, PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w emulsion solvent evaporation method using poly(vinyl alcohol, PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide, PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7 at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres.

  16. Microradiographic microsphere manipulator

    Science.gov (United States)

    Singleton, R.M.

    A method and apparatus is disclosed for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres.

  17. Starch degradability of dry and ensiled high-moisture grains of corn hybrids with different textures at different grinding degrees

    OpenAIRE

    Wagner dos Reis; Ciniro Costa; Paulo Roberto de Lima Meirelles; Marina Gabriela Berchiol da Silva; Marco Aurélio Factori; Cristiano Magalhães Pariz; Simony Alves Mendonça; Erikelly Aline Ribeiro de Santana

    2011-01-01

    This research evaluated corn grains with flint and dent texture (ensiled high-moisture or dried), submitted to grinding degrees, using the in situ ruminal degradation technique. Three rumen canulated adult sheeps were used in a complete randomized design, using a factorial outline 2 x 2 x 3, with two corn hybrids (flint and dent texture), two conservation methods (ensiled high-moisture and dry) and three grinding degress (whole, coarsely and finely ground, corresponding to the sieve of 12; 10...

  18. Effect of Enzyme Preparation with Activity Directed Towards Degradation of Non Starch Polysaccharides on Yellow Lupine Seed Based Diet for Young Broilers

    Directory of Open Access Journals (Sweden)

    Bogusław I Olkowski

    2010-01-01

    Full Text Available This work examined the impact of enzyme preparation with specific activity towards non starch polysaccharides on performance, morphological characteristics of gastrointestinal tract organs, microscopic evaluation of jejunal mucosa, and microbial status of ileum, caeca, and excreta in broilers fed a diet containing a high content of lupine meal. One-day-old chickens (Ross 308, mixed sex were randomly divided into control and experimental groups. Each group consisted of 36 birds, with 6 replications,and with 6 chickens per replication. The control group was fed the basal diet (consisting of maize and 40% of lupine, while the experimental treatment group was fed the basal diet supplemented with 0.06% commercial enzyme (Ronozyme VP. Chickens were fed diets in mash form for 4 weeks. Enzyme preparation significantly (P P P Enterobacteriaceae in caeca and excreta, and coliforms in excreta only (P < 0.01. Appropriate combination of enzyme preparations with activity towards degrading carbohydrates may offer a potential to reduce the deleterious impact of lupine in broilers.

  19. Highly efficient and porous TiO{sub 2}-coated Ag@Fe{sub 3}O{sub 4}@C-Au microspheres for degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Mao, E-mail: shenmao19820808@163.com; Chen, Suqing, E-mail: 465060605@qq.com; Jia, Wenping, E-mail: tzcjwp@tzc.edu.cn [Taizhou University, College of Pharmaceutical and Chemical Engineering (China); Fan, Guodong, E-mail: fangd@sust.edu.cn [Shan xi University of Science and Technology, Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education (China); Jin, Yanxian, E-mail: shirleyj@tzc.edu.cn; Liang, Huading, E-mail: shanjian8208@163.com [Taizhou University, College of Pharmaceutical and Chemical Engineering (China)

    2016-12-15

    In this paper, we reported a novel hierarchical porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres with a highly photocatalytic activity and magnetically separable properties. The synthesis method is included of a Fe{sub 3}O{sub 4} magnetic embedded Ag core (Ag@Fe{sub 3}O{sub 4}), an interlayer of carbon modified by PEI to form sufficient amounts of amine functional groups (Ag@Fe{sub 3}O{sub 4}@C-PEI), the grafting of Au nanoparticles on the surface of Ag@Fe{sub 3}O{sub 4}@C-PEI (Ag@Fe{sub 3}O{sub 4}@C-Au), and an ordered porous TiO{sub 2} structured shell. As an example of the applications, the photocatalytic activities of the samples were investigated by the reduction of Rhodamine B (RhB) under visible-light irradiation. The results show that the porous Ag@Fe{sub 3}O{sub 4}@C-Au@TiO{sub 2} core@shell microspheres display higher adsorption and photocatalytic activities compared to the pure porous TiO{sub 2} and Ag@Fe{sub 3}O{sub 4}@C@TiO{sub 2} microspheres, which are attributed to the local surface plasmon resonance (LSPR) by the Ag and Au nanoparticles and the high specific surface area.

  20. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...... structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics...... showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated...

  1. In situ analysis of plant tissue underivatized carbohydrates and on-probe enzymatic degraded starch by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry by using carbon nanotubes as matrix.

    Science.gov (United States)

    Gholipour, Yousef; Nonami, Hiroshi; Erra-Balsells, Rosa

    2008-12-15

    Underivatized carbohydrates of tulip bulb and leaf tissues were characterized in situ by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by using carbon nanotubes (CNTs) as matrix. Two sample preparation methods--(i) depositing CNTs on the fresh tissue slices placed on the probe and (ii) locating semitransparent tissues on a dried layer of CNTs on the probe--were examined. Furthermore, practicability of in situ starch analysis by MALDI-TOF MS was examined by detection of glucose originated from on-probe amyloglucosidase-catalyzed degradation of starch on the tissue surface. Besides, CNTs could efficiently desorb/ionize natural mono-, di-, and oligosaccharides extracted from tulip bulb tissues as well as glucose resulting from starch enzymatic degradation in vitro. These results were compared with those obtained by in situ MALDI-TOF MS analysis of similar tissues. Positive ion mode showed superior signal reproducibility. CNTs deposited under semitransparent tissue could also desorb/ionize neutral carbohydrates, leading to nearly complete elimination of matrix cluster signals but with an increase in tissue-originated signals. Furthermore, several experiments were carried out to compare the efficiency of 2,5-dihydroxybenzoic acid, nor-harmane, alpha-cyano-4-hydroxycinnamic acid, and CNTs as matrices for MALDI of neutral carbohydrates from the intact plant tissue surface and for enzymatic tissue starch degradation; these results are discussed in brief. Among matrices studied, the lowest laser power was needed to acquire carbohydrate signals with high signal-to-noise ratio and resolution when CNTs were used.

  2. Effect of the ensiling time of hydrated ground corn on silage composition and in situ starch degradability

    Directory of Open Access Journals (Sweden)

    Marcos André Arcari

    2016-04-01

    Full Text Available O objetivo deste estudo foi avaliar o efeito do tempo de ensilagem sobre a composição química e a degradabilidade in situ do amido do milho moído hidratado (MMH em grãos de média vitreosidade. Os grãos de milho foram colhidos com 83% de matéria seca (MS e vitreosidade de 67% ± 3, e foram secos até atingirem 87% de MS. Os grãos foram moídos a dois milímetros, sendo posteriormente reconstituídos, 67% MS, e ensilados (densidade de 880 kg / m³ para até 330 dias. Uma amostra MMH foi coletado mensalmente para a determinação da composição, produtos finais da fermentação e para degradabilidade in situ do amido de milho. O tempo de ensilagem não afetou o teor de MS e proteína bruta (PB. No entanto, a concentração de amido foi reduzido em 2,4 pontos percentuais em comparação de 3 com 330 dias de ensilagem. Foram observados o aumento das concentrações de N-NH3 (8,5 vezes, ácidos láctico (3,45 vezes, acético (4,1 vezes, propionico (1,7 vezes, butírico (2,8 vezes e álcool (2,4 vezes, durante o período de ensilagem. A fracção rapidamente degradável (fração A e a taxa de degradação da fracção lentamente degradável (fração C do amido do MMH foram aumentadas 3,51 e 2,21 vezes, respectivamente, durante o período de ensilagem. Por outro lado, a fração lentamente degradável (fração B do amido do MMH foi diminuída em 1,93 vezes durante o período de ensilagem. A degradabilidade efetiva do amido do MMH foi aumentado para as taxas de passagem de 0,02 / h (79,9% vs. 94,5%; 0,05 / h (65,9% vs 90,01% e de 0,08/h (56,98% vs. 86,52% quando foi comparada o período de 3 vs 330 dias de ensilagem, respectivamente. Em conclusão, o tempo de ensilagem afetou a composição química e aumentou a degradabilidade ruminal do amido do MMH de grãos com média vitreosidade.

  3. Repression of a Novel Isoform of Disproportionating Enzyme (stDPE2) in Potato Leads to Inhibition of Starch Degradation in Leaves But Not Tubers Stored at Low Temperature1

    Science.gov (United States)

    Lloyd, James R.; Blennow, Andreas; Burhenne, Kim; Kossmann, Jens

    2004-01-01

    A potato (Solanum tuberosum) cDNA encoding an isoform of disproportionating enzyme (stDPE2) was identified in a functional screen in Escherichia coli. The stDPE2 protein was demonstrated to be present in chloroplasts and to accumulate at times of active starch degradation in potato leaves and tubers. Transgenic potato plants were made in which its presence was almost completely eliminated. It could be demonstrated that starch degradation was repressed in leaves of the transgenic plants but that cold-induced sweetening was not affected in tubers stored at 4°C. No evidence could be found for an effect of repression of stDPE2 on starch synthesis. The malto-oligosaccharide content of leaves from the transgenic plants was assessed. It was found that the amounts of malto-oligosaccharides increased in all plants during the dark period and that the transgenic lines accumulated up to 10-fold more than the control. Separation of these malto-oligosaccharides by high-performance anion-exchange chromatography with pulsed-amperometric detection showed that the only one that accumulated in the transgenic plants in comparison with the control was maltose. stDPE2 was purified to apparent homogeneity from potato tuber extracts and could be demonstrated to transfer glucose from maltose to oyster glycogen. PMID:15034166

  4. Fabrication of the novel core-shell MCM-41@mTiO{sub 2} composite microspheres with large specific surface area for enhanced photocatalytic degradation of dinitro butyl phenol (DNBP)

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiao-Na; Wang, Hui-Long, E-mail: hlwang@dlut.edu.cn; Li, Zhen-Duo; Huang, Zhi-Qiang; Qi, Hui-Ping; Jiang, Wen-Feng

    2016-05-30

    Graphical abstract: The mesoporous MCM-41@mTiO{sub 2} composite microspheres with core/shell structure, well-crystallized mesoporous TiO{sub 2} layer, high specific surface, large pore volume and excellent photocatalytic activity were synthesized by combining sol-gel and simple hydrothermal treatment. - Highlights: • The mesoporous MCM-41@mTiO{sub 2} composite was synthesized successfully. • The composite was facilely prepared by combining sol-gel and hydrothermal method. • The composite exhibited high photocatalytic degradation activity for DNBP. • The composite photocatalyst has excellent reproducibility. - Abstract: The mesoporous MCM-41@mTiO{sub 2} core-shell composite microspheres were synthesized successfully by combining sol-gel and simple hydrothermal treatment. The morphology and microstructure characteristics of the synthesized materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption measurements, X-ray powder diffraction (XRD), UV–vis diffuse reflectance spectra (UV–vis/DRS) and Fourier transform infrared spectroscopy (FT-IR). The results indicate that the composite material possesses obvious core/shell structure, a pure mesoporous and well-crystallized TiO{sub 2} layer (mTiO{sub 2}), high specific surface area (316.8 m{sup 2}/g), large pore volume (0.42 cm{sup 3}/g) and two different pore sizes (2.6 nm and 11.0 nm). The photocatalytic activity of the novel MCM-41@mTiO{sub 2} composite was evaluated by degrading 2-sec-butyl-4,6-dinitrophenol (DNBP) in aqueous suspension under UV and visible light irradiation. The results were compared with commercial anatase TiO{sub 2} and Degussa P25 and the enhanced degradation were obtained with the synthesized MCM-41@mTiO{sub 2} composite under the same conditions, which meant that this material can serve as an efficient photocatalyst for the degradation of hazardous organic pollutants in wastewaters.

  5. Development of starch-based materials

    NARCIS (Netherlands)

    Habeych Narvaez, E.A.

    2009-01-01

    Starch-based materials show potential as fully degradable plastics. However, the current
    applicability of these materials is limited due to their poor moisture tolerance and
    mechanical properties. Starch is therefore frequently blended with other polymers to make
    the material more

  6. DEGRADABILIDAD DE UN POLÍMERO DE ALMIDÓN DE YUCA DEGRADABILIDADE DE UM POLÍMERO DE AMIDO DE MANDIOCA DEGRADABILITY OF A TAPIOCA STARCH POLYMER

    Directory of Open Access Journals (Sweden)

    Gladys Ruiz

    2009-12-01

    mineralização, assim como mudanças nas propriedades mecânicas, morfologia superficial, absorvância em IV e perda de peso, dependendo do tipo de meio. Dos resultados obtidos se encontrou que o polímero é degradado ao estar submetido à simulação de aterro sanitário, água salgada e, em menor medida, à luz solar, enquanto na água doce o polímero não se degrada.The use of polymeric materials has been increased due to their good properties and low cost. As a result, the amount of plastic that gets to landfills has increased until 30 %. As a solution to this problem, biodegradable polymers have been developed; and compared to synthetic polymers, they are degraded in the environment when exposed to certain conditions in a shorter period. One of the raw materials that is widely used in the manufacturing of biodegradable materials is starch. In this research study, the biodegradability of a polymer made of tapioca starch has been studied. To determine this, the polymer has been characterized and exposed to salt and fresh water, sunlight and a simulation of a landfill for a series of periods. To determine its biodegradability, percentage of mineralization was measured as well as changes in tensile properties, superficial morphology, IR absorption and weight loss depending on the type of environment. From the results it was found that the polymer is degraded by being subjected to simulated landfill, salt water and to a lesser extent in sunlight, while in fresh water it does not get degraded.

  7. Defining Starch Binding by Glucan Phosphatases

    DEFF Research Database (Denmark)

    Auger, Kyle; Raththagala, Madushi; Wilkens, Casper

    2015-01-01

    Starch is a vital energy molecule in plants that has a wide variety of uses in industry, such as feedstock for biomaterial processing and biofuel production. Plants employ a three enzyme cyclic process utilizing kinases, amylases, and phosphatases to degrade starch in a diurnal manner. Starch...... is comprised of the branched glucan amylopectin and the more linear glucan amylose. Our lab has determined the first structures of these glucan phosphatases and we have defined their enzymatic action. Despite this progress, we lacked a means to quickly and efficiently quantify starch binding to glucan...

  8. Study of the effect of γ-absorbed dose on degradation of polypropylene/starch-filled polymer containing photo-initiators by spectroscopic methods

    Science.gov (United States)

    Bagheri, Rouhollah.

    2009-09-01

    γ irradiated samples containing photo-initiators (PIs) with and without corn starch at 0-60 kGy were studied by UV spectrophotometer and FTIR. A linear decrease in the wavelength of absorbance maximum of each aromatic PI is observed by increase in the dose. The presence of starch in the sample caused a fluctuation of the absorptions. An increase in carbonyl formation due to the effect of a PI was detected. Ferric stearate and Irgacure 184 showed the highest and lowest effect respectively.

  9. Metallic coating of microspheres

    International Nuclear Information System (INIS)

    Meyer, S.F.

    1980-01-01

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

  10. Metallic coating of microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, S.F.

    1980-08-15

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates.

  11. Flow injection spectrophotometric analysis of human salivary α-amylase activity using an enzyme degradation of starch-iodine complexes in flow channel and its application to human stress testing.

    Science.gov (United States)

    Ohtomo, Takao; Igarashi, Shukuro; Takagai, Yoshitaka

    2013-01-01

    Flow injection spectrophotometric analysis (FIA) of human salivary α-amylase was developed using an enzyme degradation reaction of starch-iodine complexes. In this proposed method, the salivary α-amylase, known as a human stress indicator, is directly and rapidly determined without any pretreatment. In this study, the optimum starch-iodine complexes (i.e., optimum molecular weight and amylase-amylopectin compounding ratio) were selected, and their rapid degradation in the flow channel was investigated to determine salivary amylase in the FIA system. The determination range of α-amylase was obtained from 0.25 to 5.0 kilo Novo unit per milliliter (KNU/mL), and these concentrations were equivalent to the real concentration of amylase in human saliva. The quantitative values obtained by this method were found to be highly reproducible with 1.6% (n=25) of the relative standard deviation for 1.0 KNU/mL. The detection limit (3σ) was 60 NU/mL. In addition, the method requires small volume of a sample (20 µL), and 30 samples was sequentially measured within one hour. Real human saliva collected before and after exercise was utilized to demonstrate the feasibility of human stress test and analytical performance of this approach.

  12. Valor nutritivo de rações compostas de fontes de amido e de nitrogênio com alta e baixa degradabilidade ruminal Nutritive value of diets composed by starch and nitrogen sources with high and low ruminal degradability

    Directory of Open Access Journals (Sweden)

    Lúcia Maria Zeoula

    1999-01-01

    Full Text Available O objetivo deste estudo foi avaliar o consumo, o coeficiente de digestibilidade aparente (CDA, o balanço de nitrogênio, o pH e a concentração de nitrogênio amoniacal no líquido ruminal de ovinos. Os animais foram alimentados com rações compostas de concentrados com diferentes degradabilidade ruminal das frações amido e nitrogênio das seguintes fontes: amido (AM de alta (triticale e baixa (milho degradabilidade ruminal combinada com fontes de nitrogênio (N de alta (farelo de canola + uréia e baixa (farelo de algodão + farinha de carne e ossos degradabilidade ruminal. Dezesseis carneiros Suffok castrados com peso médio de 37 kg PV foram usados para estimar os CDA por intermédio do método de coleta total de fezes e urina. O delineamento experimental foi inteiramente casualizado, com arranjo fatorial 2 x 2, com quatro repetições por tratamento. Na avaliação do pH e nitrogênio amoniacal, o delineamento usado foi de parcelas subdivididas, sendo os tratamentos considerados como parcelas e os tempos de amostragem como subparcelas. Maiores consumos de matéria seca (MS, proteína bruta (PB e fibra em detergente neutro (FDN foram observados nos animais alimentados com as rações que continham fontes de N de baixa degradabilidade ruminal. Maiores CDA da MS, PB e energia bruta foram observados para as rações com fontes de N de alta degradabilidade ruminal e do AM, para as rações com fontes de AM e N de alta degradabilidade ruminal. A fonte de N de baixa degradabilidade ruminal propiciou o maior valor de pH e a mais baixa concentração de amônia ruminal.The objective of this study was to evaluate the intake, apparent digestibility coefficient (ADC, nitrogen balance, pH and nitrogen ammonia concentration (N-NH3 in the ruminal fluid of sheep. The animals were fed diets composed by concentrates with different ruminal degradability of the fractions starch and protein from the used sources: starch with high (triticale and low (corn

  13. Design starch: stochastic modeling of starch granule biogenesis.

    Science.gov (United States)

    Raguin, Adélaïde; Ebenhöh, Oliver

    2017-08-15

    Starch is the most widespread and abundant storage carbohydrate in plants and the main source of carbohydrate in the human diet. Owing to its remarkable properties and commercial applications, starch is still of growing interest. Its unique granular structure made of intercalated layers of amylopectin and amylose has been unraveled thanks to recent progress in microscopic imaging, but the origin of such periodicity is still under debate. Both amylose and amylopectin are made of linear chains of α-1,4-bound glucose residues, with branch points formed by α-1,6 linkages. The net difference in the distribution of chain lengths and the branching pattern of amylose (mainly linear), compared with amylopectin (racemose structure), leads to different physico-chemical properties. Amylose is an amorphous and soluble polysaccharide, whereas amylopectin is insoluble and exhibits a highly organized structure of densely packed double helices formed between neighboring linear chains. Contrarily to starch degradation that has been investigated since the early 20th century, starch production is still poorly understood. Most enzymes involved in starch growth (elongation, branching, debranching, and partial hydrolysis) are now identified. However, their specific action, their interplay (cooperative or competitive), and their kinetic properties are still largely unknown. After reviewing recent results on starch structure and starch growth and degradation enzymatic activity, we discuss recent results and current challenges for growing polysaccharides on granular surface. Finally, we highlight the importance of novel stochastic models to support the analysis of recent and complex experimental results, and to address how macroscopic properties emerge from enzymatic activity and structural rearrangements. © 2017 The Author(s).

  14. Design starch: stochastic modeling of starch granule biogenesis

    Science.gov (United States)

    Ebenhöh, Oliver

    2017-01-01

    Starch is the most widespread and abundant storage carbohydrate in plants and the main source of carbohydrate in the human diet. Owing to its remarkable properties and commercial applications, starch is still of growing interest. Its unique granular structure made of intercalated layers of amylopectin and amylose has been unraveled thanks to recent progress in microscopic imaging, but the origin of such periodicity is still under debate. Both amylose and amylopectin are made of linear chains of α-1,4-bound glucose residues, with branch points formed by α-1,6 linkages. The net difference in the distribution of chain lengths and the branching pattern of amylose (mainly linear), compared with amylopectin (racemose structure), leads to different physico-chemical properties. Amylose is an amorphous and soluble polysaccharide, whereas amylopectin is insoluble and exhibits a highly organized structure of densely packed double helices formed between neighboring linear chains. Contrarily to starch degradation that has been investigated since the early 20th century, starch production is still poorly understood. Most enzymes involved in starch growth (elongation, branching, debranching, and partial hydrolysis) are now identified. However, their specific action, their interplay (cooperative or competitive), and their kinetic properties are still largely unknown. After reviewing recent results on starch structure and starch growth and degradation enzymatic activity, we discuss recent results and current challenges for growing polysaccharides on granular surface. Finally, we highlight the importance of novel stochastic models to support the analysis of recent and complex experimental results, and to address how macroscopic properties emerge from enzymatic activity and structural rearrangements. PMID:28673938

  15. Microbial biodegradable potato starch based low density polyethylene

    African Journals Online (AJOL)

    USER

    2010-06-28

    Jun 28, 2010 ... (Raj, 2003). Also, starch based plastic did not have a negative effect on the environment and also reduced the green house effect (Bastioli, 2001). Synthetic plastic takes a long time to degrade in nature. The use of starch as a biodegradable agent accelarated the time of degradation in the environment.

  16. Microbial biodegradable potato starch based low density polyethylene

    African Journals Online (AJOL)

    Plastic materials remain in the nature for decades. Slow degradation of plastics in the environment caused a public trend to biodegradable polymers. The aim of this research was to produce the microbial biodegradable low density polyethylene with potato starch. Degradation of potato starch based low density polyethylene ...

  17. Polymeric Microspheres for Medical Applications

    Directory of Open Access Journals (Sweden)

    Ketie Saralidze

    2010-06-01

    Full Text Available Synthetic polymeric microspheres find application in a wide range of medical applications. Among other applications, microspheres are being used as bulking agents, embolic- or drug-delivery particles. The exact composition of the spheres varies with the application and therefore a large array of materials has been used to produce microspheres. In this review, the relation between microsphere synthesis and application is discussed for a number of microspheres that are used for different treatment strategies.

  18. 1H-13C NMR-based profiling of biotechnological starch utilization

    DEFF Research Database (Denmark)

    Sundekilde, Ulrik K.; Meier, Sebastian

    2016-01-01

    Starch is used in food-and non-food applications as a renewable and degradable source of carbon and energy. Insight into the chemical detail of starch degradation remains challenging as the starch constituents amylose and amylopectin are homopolymers. We show that considerable molecular detail...... of starch fragmentation can be obtained from multivariate analysis of spectral features in optimized 1H-13C NMR spectroscopy of starch fragments to identify relevant features that distinguish processes in starch utilization. As a case study, we compare the profiles of starch fragments in commercial beer...... samples. Spectroscopic profiles of homooligomeric starch fragments can be excellent indicators of process conditions. In addition, differences in the structure and composition of starch fragments have predictive value for down-stream process output such as ethanol production from starch. Thus, high...

  19. Hyperphosphorylation of cereal starch

    DEFF Research Database (Denmark)

    Carciofi, Massimiliano; Shaik, Shahnoor Sultana; Jensen, Susanne Langgård

    2011-01-01

    Plant starch is naturally phosphorylated at a fraction of the C6 and the C3 hydroxyl groups during its biosynthesis in plastids. Starch phosphate esters are important in starch metabolism and they also generate specific industrial functionality. Cereal grains starch contains little starch bound...... phosphate compared with potato tuber starch and in order to investigate the effect of increased endosperm starch phosphate, the potato starch phosphorylating enzyme glucan water dikinase (StGWD) was overexpressed specifically in the developing barley endosperm. StGWD overexpressors showed wild......-type phenotype. Transgenic cereal grains synthesized starch with higher starch bound phosphate content (7.5 (±0.67) nmol/mg) compared to control lines (0.8 (±0.05) nmol/mg) with starch granules showing altered morphology and lower melting enthalpy. Our data indicate specific action of GWD during starch...

  20. Concerted suppression of all starch branching enzyme genes in barley produces amylose-only starch granules

    DEFF Research Database (Denmark)

    Carciofi, Massimiliano; Blennow, Andreas; Jensen, Susanne L

    2012-01-01

    Background Starch is stored in higher plants as granules composed of semi-crystalline amylopectin and amorphous amylose. Starch granules provide energy for the plant during dark periods and for germination of seeds and tubers. Dietary starch is also a highly glycemic carbohydrate being degraded...... to glucose and rapidly absorbed in the small intestine. But a portion of dietary starch, termed "resistant starch" (RS) escapes digestion and reaches the large intestine, where it is fermented by colonic bacteria producing short chain fatty acids (SCFA) which are linked to several health benefits. The RS...... is preferentially derived from amylose, which can be increased by suppressing amylopectin synthesis by silencing of starch branching enzymes (SBEs). However all the previous works attempting the production of high RS crops resulted in only partly increased amylose-content and/or significant yield loss. Results...

  1. Modification of rice starch by gamma irradiation to produce soluble starch of low viscosity for industrial purposes

    International Nuclear Information System (INIS)

    El Saadany, R.M.A.; El Saadany, F.M.; Foda, Y.H.

    1974-01-01

    Because starch of low viscosity is important for industrial purposes this research was carried out to study the possibility of producing this sort of starch by treating rice starch with γ-irradiation. Results indicated than when rice starch was modified by γ-irradiation, the reducing power increased and degradation as well as molecular breakdown occured followed by sharp decrease of its viscosity, specific viscosity and intrisinc viscosity. Results showed that starch became more soluble by treating with γ-irradiation and lost its resistance to water as its swelling capacity decreased. All these changes were proportional to the doses of γ-irradiation. (orig.) [de

  2. Aroma interactions with starch

    DEFF Research Database (Denmark)

    Jørgensen, Anders Dysted

    Starches are used to enhance aroma perception in low-fat foods. Aroma compounds can bind physically to the starch in grooves on the surface or they can form complexes inside amylose helices. This study has been divided into two parts: one part regarding binding of aromas to starches and their aroma......-release, and another part regarding stimulation of a fungal secretome using different carbohydrates. In the first part, nine aromas and one aroma-mixture were mixed with nine different starches, including genetically modified starches. The objective of this sub-project was to bind aromas to the starches to 15 weight......-percent. Aroma binding was tested on both amorphous starches and on native starch granules. A series of aldehydes and alcohols were also tested for binding to the starches. The aromas with the highest volatility were positively retained by starch, whereas for aromas with a lower volatility the starch had...

  3. Effect of ionizing radiation on starch and cellulose

    International Nuclear Information System (INIS)

    Klenha, J.; Bockova, J.

    1973-09-01

    The investigation is reported of the effects of ionizing radiation both on macromolecular systems generally and on polysaccharides, starch and cellulose. Attention is focused on changes in the physical and physico-chemical properties of starch and cellulose, such as starch swelling, gelation, viscosity, solubility, reaction with iodine, UV, IR and ESR spectra, chemical changes resulting from radiolysis and from the effect of amylases on irradiated starch, changes in cellulose fibre strength, water absorption, stain affinity, and also the degradation of cellulose by radiation and the effect of cellulases on irradiated cellulose. Practical applications of the findings concerning cellulose degradation are discussed. (author)

  4. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    Prado, Miguel O.; Prastalo, Simon; Blaumann, Herman; Longhino, Juan M.; Repetto Llamazares, A.H.V.

    2007-01-01

    We developed the capacity to produce glass microspheres containing in their structure one or more radioactive isotopes useful for brachytherapy. We studied the various facts related with their production: (Rare earth) alumino silicate glass making, glass characterization, microspheres production, nuclear activation through (n,γ) nuclear reactions, mechanical characterization before and after irradiation. Corrosion tests in simulated human plasma and mechanical properties characterization were done before and after irradiation. (author) [es

  5. INVESTIGATION OF DRUG RELEASE FROM BIODEGRADABLE PLG MICROSPHERES: EXPERIMENT AND THEORY

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS, MALCOLM J. [Los Alamos National Laboratory; BERCHANE, NADER S. [Los Alamos National Laboratory; CARSON, KENNETH H. [Los Alamos National Laboratory; RICE-FICHT, ALLISON C. [Los Alamos National Laboratory

    2007-01-30

    Piroxicam containing PLG microspheres having different size distributions were fabricated, and in vitro release kinetics were determined for each preparation. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the system size was increased. The mathematical model gave a good fit to the experimental release data.

  6. Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

    Science.gov (United States)

    Chen, Xingtao; Lv, Guoyu; Zhang, Jue; Tang, Songchao; Yan, Yonggang; Wu, Zhaoying; Su, Jiacan; Wei, Jie

    2014-01-01

    A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery. PMID:24855351

  7. Method for sizing hollow microspheres

    Science.gov (United States)

    Farnum, E.H.; Fries, R.J.

    1975-10-29

    Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

  8. Proteína degradável no rúmen associada a fontes de amido de alta ou baixa degradabilidade: digestibilidade in vitro e desempenho de novilhos em crescimento Rumen degradable protein associated to starch sources of different ruminal degradability: in vitro digestibility and performance of growing steers

    Directory of Open Access Journals (Sweden)

    Saul Ferreira Caldas Neto

    2007-04-01

    Full Text Available Objetivou-se avaliar os efeitos de teores crescentes de proteína degradável no rúmen (PDR = 47, 52, 57 e 62% associados a fontes de amido de baixa (milho ou de alta (farinha de varredura de mandioca - FVM degradabilidade ruminal em rações com 50:50% volumoso:concentrado sobre a digestibilidade in vitro da MS (DIVMS e o ganho de peso de novilhos em crescimento. Para determinação da DIVMS, foi utilizada a técnica de dois estádios de Tilley & Terry (1963. As médias obtidas para a DIVMS foram submetidas às análises de variância e regressão em função do teor de PDR da ração. Para o ensaio de desempenho animal, foram utilizados 32 novilhos mestiços (Nelore x Red Angus, não-castrados (275 kg de PV, alojados em duplas, em delineamento experimental inteiramente casualizado. Não foi observado efeito do teor de PDR de dietas contendo milho sobre a DIVMS, indicando que não houve deficiência de nitrogênio e que, possivelmente, a digestibilidade da fonte de amido (milho foi o fator limitante. Observou-se efeito quadrático do teor de PDR sobre a DIVMS para as dietas contendo FVM, o que indica a ocorrência do efeito de sincronização entre a disponibilidade de energia e nitrogênio, permitindo aumento da atividade microbiana nos níveis mais elevados de PDR na ração e melhor utilização da energia proveniente da fonte de amido de alta degradabilidade ruminal. Não foi observado efeito dos diferentes teores de PDR e da fonte de amido de alta degradabilidade ruminal sobre o consumo de MS, o ganho de peso médio e a conversão alimentar dos animais.The objective of this study was to evaluate the effects of increasing levels of rumen-degradable protein (RDP = 47, 52, 57 and 62% associated to starch sources of low (corn and high (cassava by-product (CBP ruminal degradability on in vitro DM digestibility (IVDMD and average daily gain of growing steers. In vitro DM digestibility was determined by using the Tilley and Terry (1963 technique

  9. Starch bioengineering affects cereal grain germination and seedling establishment

    OpenAIRE

    Shaik, Shahnoor S.; Carciofi, Massimiliano; Martens, Helle J.; Hebelstrup, Kim H.; Blennow, Andreas

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphospho...

  10. Dynamics of starch granule biogenesis - the role of redox-regulated enzymes and low-affinity carbohydrate-binding modules

    DEFF Research Database (Denmark)

    Blennow, A.; Svensson, Birte

    2010-01-01

    The deposition and degradation of starch in plants is subject to extensive post-translational regulation. To permit degradation of B-type crystallites present in tuberous and leaf starch these starch types are phosphorylated by glucan, water dikinase (GWD). At the level of post-translational redo...

  11. Preparation of alumina microspheres

    International Nuclear Information System (INIS)

    Santos, W.R. dos; Abrao, A.

    1980-01-01

    Inorganic exchangers are widely used for adsorption and column partition chromatography. The main difficulty of using commercial alumina (in powder) for column chromatography is related to its packing, and the operations through the column become diffcult and time-consuming; also it turns to be virtually impossible to use large dimension columns. In order to eliminate these problems, a process for the preparation of alumina micro-spheres was developed as an adaptation of a similar process used to prepare nuclear fuel microspheres (UO 2 , ThO 2 ). The flowsheet of this process is presented together with the analytical results of sphericity after calcination, granulometry, density and characterization by X-ray diffractometry. Solubility tests showed that the so-prepared microspheres are well resistant to strong acids and bases; retention tests showed their efficiency, mainly to copper. (C.L.B.) [pt

  12. What happens in the bag? : development and evaluation of a modified in situ protocol to estimate degradation of nitrogen and starch in the rumen

    NARCIS (Netherlands)

    Jonge, de L.H.

    2015-01-01

    The most widely used method to estimate the rumen degradation of dietary components in feedstuffs is the in situ or in sacco method. This method is based on rumen incubation of substrate (feed) in nylon or dacron bags followed by rinsing and analysis of the residue. Small pores

  13. Starch modification with microbial alpha-glucanotransferase enzymes

    NARCIS (Netherlands)

    van der Maarel, Marc J. E. C.; Leemhuis, Hans

    2013-01-01

    Starch is an agricultural raw material used in many food and industrial products. It is present in granules that vary in shape in the form of amylose and amylopectin. Starch-degrading enzymes are used on a large scale in the production of sweeteners (high fructose corn syrup) and concentrated

  14. Combination of malted cereals and cassava starch in the production ...

    African Journals Online (AJOL)

    The relative capacity of malted cereals and their optimum conditions of temperature and pH in the hydrolysis of starch were studied. Malted cereals prepared from rice, maize, sorghum and millet were used to degrade cassava starch to produce sugar syrup. Effect of pH and temperature on the level of dextrose equivalent ...

  15. Processing surface sizing starch using oxidation, enzymatic hydrolysis and ultrasonic treatment methods--Preparation and application.

    Science.gov (United States)

    Brenner, Tobias; Kiessler, Birgit; Radosta, Sylvia; Arndt, Tiemo

    2016-03-15

    The surface application of starch is a well-established method for increasing paper strength. In surface sizing, a solution of degraded starch is applied to the paper. Two procedures have proved valuable for starch degradation in the paper mill: enzymatic and thermo-oxidative degradation. The objective of this study was to determine achievable efficiencies of cavitation in preparing degraded starch for surface application on paper. It was found that ultrasonic-assisted starch degradation can provide a starch solution that is suitable for surface sizing. The molecular composition of starch solutions prepared by ultrasonic treatment differed from that of starch solutions degraded by enzymes or by thermo-oxidation. Compared to commercial degradation processes, this resulted in intensified film formation and in greater penetration during surface sizing and ultimately in a higher starch content of the paper. Paper sized with ultrasonically treated starch solutions show the same strength properties compared to commercially sized paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Improved starch recovery from potatoes by enzymes and reduced water holding of the residual fibres

    NARCIS (Netherlands)

    Ramaswamy, U.R.; Lips, S.J.J.; Bakker, R.R.; Gruppen, H.; Kabel, M.A.

    2014-01-01

    During the industrial extraction of starch from potatoes (Seresta), some starch remains within undisrupted potato cells in the fibrous side-stream. The aim of this study was to investigate if enzymatic degradation of cell wall polysaccharides (CWPs) can enhance starch recovery and lower the water

  17. Albumin-heparin microspheres as carriers for cytostatic agents

    NARCIS (Netherlands)

    Cremers, Harry; Feijen, Jan; Kwon, G.; Bae, Y.H.; Kim, S.W.; Noteborn, H.P.J.M.; Mcvie, J.G.

    1990-01-01

    Much work has been done on adriamycin-loaded albumin microspheres (Alb-MS) for chemoembolization [1–4], the rationale being that site-specific drug delivery may increase the therapeutic efficacy of the drug. Alb-Ms are being investigated because of their biocompatibility and because the degradation

  18. Fusion microsphere targets

    International Nuclear Information System (INIS)

    Koo, J.C.

    1980-01-01

    It was shown that a microsphere within the structure limitations is hydrodynamically stable. To insure its perfect formation, the initial chemical compositions must have a blowing capability, more important, the resultant liquid compositions must also have sufficient surface tension and low viscosity

  19. Effects of Xylanase Supplementation on Growth Performance, Nutrient Digestibility and Non-starch Polysaccharide Degradation in Different Sections of the Gastrointestinal Tract of Broilers Fed Wheat-based Diets

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2014-06-01

    Full Text Available This experiment was performed to investigate the effects of exogenous xylanase supplementation on performance, nutrient digestibility and the degradation of non-starch polysaccharides (NSP in different sections of the gastrointestinal tract (GIT of broilers fed wheat-based diets. A total of 120 7-day-old Arbor Acres broiler chicks were randomly allotted to two wheat-based experimental diets supplemented with 0 or 1.0 g/kg xylanase. Each treatment was composed of 6 replicates with 10 birds each. Diets were given to the birds from 7 to 21 days of age. The results showed that xylanase supplementation did not affect feed intake, but increased body weight gain of broiler at 21 day of age by 5.8% (pjejunum>duodenum>>gizzard> caecum. The supplementation of xylanse increased ileal isomaltriose concentration (p<0.05, but did not affect the concentrations of isomaltose, panose and 1-kestose in the digesta of all GIT sections. These results suggest that supplementation of xylanase to wheat-based diets cuts the arabinoxylan backbone into small fragments (mainly arabinose and xylose in the ileum, jejunum and duodenum, and enhances digestibilites of nutrients by decreasing digesta viscosity. The release of arabinose and xylose in the small intestine may also be the important contributors to the growth-promoting effect of xylanase in broilers fed wheat-based diets.

  20. Thermomechanical treatment of starch

    NARCIS (Netherlands)

    Goot, van der A.J.; Einde, van den R.M.

    2006-01-01

    Starch is used as a major component in many food and nonfood applications and determines the overall product properties to a large extent. It is therefore important to understand the effect of processing on starch. Many starch-based products are produced using a thermal as well as a mechanical

  1. The physical and chemical stability of suspensions of sustained-release diclofenac microspheres.

    Science.gov (United States)

    Lewis, L; Boni, R L; Adeyeye, C M

    1998-01-01

    The major challenge in liquid sustained-release oral suspensions is to minimize drug diffusion into the suspending medium and to retain the original properties of the microparticles during storage. Diclofenac wax microspheres prepared by the hydrophobic congealable disperse phase method were formulated as a sustained release suspension and stored at three different temperatures (25, 37 and 45 degrees C) for 3 months, to evaluate the physical and chemical stability of the suspended microspheres. Suspensions of microspheres stored at ambient temperatures were both physically and chemically stable, but at higher temperatures, up to 45 degrees C, there was a decrease in drug release due to scaling and melting on the microsphere surface as observed by scanning electron microscopy. However, on prolonged storage, up to 90 days, especially at 45 degrees C, temperature became a dominant factor causing an increase in drug release. The suspension of diclofenac microspheres was chemically stable for 3 months, while the plain drug suspension exhibited slight degradation.

  2. Floating microspheres of valacyclovir HCl: Formulation, optimization, characterization, in vitro and in vivo floatability studies

    Directory of Open Access Journals (Sweden)

    Nilamgiri Goswami

    2012-01-01

    Full Text Available Floating microspheres are multiple unit Gastroretentive drug delivery systems. Valacyclovir hydrochloride (VCH is L-valyl ester prodrug of acyclovir. VCH degrades in intestinal fluid. The objective was to develop floating microspheres of VCH to localise the drug at upper part of GIT, for improved absorption. Floating microspheres were prepared by W/O emulsification solvent evaporation method using Ethylcellulose (EC as polymer. Particle size and % EE were 550.021±0.241 μm, 79.88±2.236% respectively. in vitro and in vivo floatability studies confirmed floating behaviour of microspheres. VCH loaded floating microspheres can be a suitable alternative to the conventional formulation, by localizing the drug at upper GIT.

  3. Storage stability of biodegradable polyethylene glycol microspheres

    Science.gov (United States)

    Jain, Era; Sheth, Saahil; Polito, Kristen; Sell, Scott A.; Zustiak, Silviya P.

    2017-10-01

    Degradable hydrogel microspheres are popular choices for multiple biomedical applications, including drug, protein, or cell carriers for minimally invasive delivery. Clinical transitioning of such new, sensitive pharmaceutical preparations requires investigation of storage methods that retain key properties for extended time. In this study, we sought to determine the influence of seven common storage conditions on the physical and mechanical properties of degradable polyethylene glycol (PEG) hydrogel microspheres: 25 °C, 4 °C, -80 °C, lyophilization/-20 °C, dimethyl sulfoxide/-80 °C, dimethyl sulfoxide/lyophilization/-20 °C, vacuum/-20 °C. We have outlined the storage conditions in detail and explained their effect on swelling ratio, stiffness and degradation rate post-storage. Additionally, we have implemented protein-loaded hydrogels to evaluate the effect of storage conditions on diffusivity as well as protein stability post-storage. We found that hydrogels could be stored short-term (1-4 d) under moist conditions (i.e. storage without drying) without a substantial loss of properties. For extended storage (7-28 d), they could be stored either at  -80 °C (moist condition) or vacuum drying (dry condition).

  4. Synthesis of magnetic polymeric microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I [M.V. Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation)

    2010-05-13

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  5. Synthesis of magnetic polymeric microspheres

    International Nuclear Information System (INIS)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I

    2010-01-01

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  6. Radioactive Microspheres for Medical Applications

    Science.gov (United States)

    HÄfeli, Urs

    This paper reviews the preparation and application of radioactive microspheres for medical purposes. It first discusses the properties of relevant radioisotopes and then explores the diagnostic uses of gamma-emitter labelled microspheres, such as blood flow measurement and imaging of the liver and other organs. The therapeutic uses of alpha- and beta-emitting microspheres, such as radioembolization, local tumour therapy and radiosynovectomy, are then described, and the recent developments in neutron capture therapy using gadolinium microspheres and boron liposomes discussed. The review concludes with some considerations in radiopharmaceutical kit preparations and radioisotope generator use, as well as with some radiobiological and dosimetric concerns.

  7. Starch bioengineering affects cereal grain germination and seedling establishment.

    Science.gov (United States)

    Shaik, Shahnoor S; Carciofi, Massimiliano; Martens, Helle J; Hebelstrup, Kim H; Blennow, Andreas

    2014-06-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated for both HP and AO lines as compared with the WT. At late seedling establishment stages, specific sugars were rapidly consumed in the AO line. α-Amylase activity was distinctly suppressed in both the HP and the AO lines. Pre-germination β-amylase deposition was low in the AO grains and β-amylase was generally suppressed in both HP and AO lines throughout germination. As further supported by scanning electron microscopy and histochemical analyses on grain and seedlings, it was concluded that inadequate starch granule deposition in combination with the suppressed hydrolase activity leads to temporal and compensating re-direction of starch, sugar, and protein catabolism important to maintain metabolic dynamics during grain germination and seedling establishment. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  8. Thermoplastic starch materials prepared from rice starch

    International Nuclear Information System (INIS)

    Pontes, Barbara R.B.; Curvelo, Antonio A.S.

    2009-01-01

    Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

  9. Investigation of Starch Binding Domains for Improvement of Starch degradation

    DEFF Research Database (Denmark)

    Christiansen, Camilla

    Dansk resume Stivelse er planternes primære energilager og et vigtigt næringsmiddel for pattedyr,svampe og bakterier. Stivelse deponeres i højt organiserede semi-krystallinske stivelseskorn i plastider: kloroplaster i blade (transitorisk stivelse) og amyloplaster i lagerorganer som knolde. Stivel...

  10. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  11. The effect of thermomechanical treatment on starch breakdown and the consequences for process design

    NARCIS (Netherlands)

    Einde, van den R.M.; Bolsius, A.; Soest, van J.J.G.; Janssen, L.P.B.M.; Goot, van der A.J.; Boom, R.M.

    2004-01-01

    Macromolecular degradation of starch by heating and shear forces was investigated using a newly developed shear cell. With this equipment, waxy corn starch was subjected to a variety of heat and shear treatments in order to find the key parameter determining the degree of macromolecular degradation.

  12. Concerted suppression of all starch branching enzyme genes in barley produces amylose-only starch granules

    DEFF Research Database (Denmark)

    Carciofi, Massimiliano; Blennow, Per Gunnar Andreas; Jensen, Susanne Langgård

    2012-01-01

    , a very high content of RS (65 %) was observed, which is 2.2-fold higher than control (29%). The amylose-only grains germinated with same frequency as control grains. However, initial growth was delayed in young plants. Conclusions This is the first time that pure amylose has been generated with high......Background Starch is stored in higher plants as granules composed of semi-crystalline amylopectin and amorphous amylose. Starch granules provide energy for the plant during dark periods and for germination of seeds and tubers. Dietary starch is also a highly glycemic carbohydrate being degraded...... amylose-only grains may be due to an important physiological role played by amylopectin ordered crystallinity for rapid starch remobilization explaining the broad conservation in the plant kingdom of the amylopectin structure....

  13. Influence of excipients on characteristics and release profiles of poly(ε-caprolactone) microspheres containing immunoglobulin G

    Energy Technology Data Exchange (ETDEWEB)

    Erdemli, Özge [Department of Engineering Sciences, Middle East Technical University, Ankara (Turkey); Keskin, Dilek [Department of Engineering Sciences, Middle East Technical University, Ankara (Turkey); Biomaterials and Tissue Engineering Center of Excellence, Middle East Technical University, Ankara (Turkey); Tezcaner, Ayşen, E-mail: tezcaner@metu.edu.tr [Department of Engineering Sciences, Middle East Technical University, Ankara (Turkey); Biomaterials and Tissue Engineering Center of Excellence, Middle East Technical University, Ankara (Turkey)

    2015-03-01

    Protein instability during microencapsulation has been one of the major drawbacks of protein delivery systems. In this study, the effects of various excipients (poly vinyl alcohol, glucose, starch, heparin) on the stability of encapsulated human immunoglobulin G (IgG) in poly(ε-caprolactone) (PCL) microspheres and on microsphere characteristics were investigated before and after γ-sterilization. Microspheres formulated without any excipients and with glucose had a mean particle size around 3–4 μm whereas the mean particle sizes of other microspheres were around 5–6 μm. Use of PVA significantly increased the IgG-loading and encapsulation efficiency of microspheres. After γ-irradiation, IgG stability was mostly maintained in the microspheres with excipients compared to microspheres without any excipients. According to the μBCA results, microspheres without any excipient showed a high initial burst release as well as a fast release profile among all groups. Presence of PVA decreased the loss in the activity of IgG released before (completely retained after 6 h and 15.69% loss after 7 days) and after γ-irradiation (26.04% loss and 52.39% loss after 6 h and 7 days, respectively). The stabilization effect of PVA on the retention of the activity of released IgG was found more efficient compared to other groups formulated with carbohydrates. - Highlights: • Good excipient provides retention of protein stability during microencapsulation. • PVA was more effective on retention of the IgG stability compared to carbohydrates. • Starch was not an appropriate excipient for the retention of IgG stability.

  14. Relationships between PSII-independent hydrogen bioproduction and starch metabolism as evidenced from isolation of starch catabolism mutants in the green alga Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Chochois, Vincent; Constans, Laure; Beyly, Audrey; Soliveres, Melanie; Peltier, Gilles; Cournac, Laurent [CEA, DSV, IBEB, Laboratoire de Bioenergetique et Biotechnologie des Bacteries and Microalgues, Saint Paul Lez Durance, F-13108 (France); CNRS, UMR Biologie Vegetale and Microbiologie Environnementales, Saint Paul lez Durance, F-13108 (France); Aix-Marseille Universite, Saint Paul lez Durance, F-13108 (France); Dauvillee, David; Ball, Steven [Univ Lille Nord de France, F-59000 Lille (France); USTL, UGSF, F-59650 Villeneuve d' Ascq (France); CNRS, UMR 8576, F-59650 Villeneuve d' Ascq (France)

    2010-10-15

    Sulfur deprivation, which is considered as an efficient way to trigger long-term hydrogen photoproduction in unicellular green algae has two major effects: a decrease in PSII which allows anaerobiosis to be reached and carbohydrate (starch) storage. Starch metabolism has been proposed as one of the major factors of hydrogen production, particularly during the PSII-independent (or indirect) pathway. While starch biosynthesis has been characterized in the green alga Chlamydomonas reinhardtii, little remains known concerning starch degradation. In order to gain a better understanding of starch catabolism pathways and identify those steps likely to limit the starch-dependent hydrogen production, we have designed a genetic screening procedure aimed at isolating mutants of the green alga C. reinhardtii affected in starch mobilization. Using two different screening protocols, the first one based on aerobic starch degradation in the dark and the second one on anaerobic starch degradation in the light, eighteen mutants were isolated among a library of 15,000 insertion mutants, eight (std1-8) with the first screen and ten (sda1-10) with the second. Most of the mutant strains isolated in this study showed a reduction or a delay in the PSII-independent hydrogen production. Further characterization of these mutants should allow the identification of molecular determinants of starch-dependent hydrogen production and supply targets for future biotechnological improvements. (author)

  15. Enzymatic modification of starch

    DEFF Research Database (Denmark)

    Jensen, Susanne Langgård

    In the food industry approaches for using bioengineering are investigated as alternatives to conventional chemical and physical starch modification techniques in development of starches with specific properties. Enzyme-assisted post-harvest modification is an interesting approach to this, since...... it is considered a clean and energy saving technology. This thesis aimed to investigate the effect of using reaction conditions, simulating an industrial process, for enzymatic treatment of starch with branching enzyme (BE) from Rhodothermus obamensis. Thus treatements were conducted at 70°C using very high...... of the obtained products and were correlated to properties of the starch substrates. It was found that the obtained products differed depending on both the conditions used and the properties of the starch. Products of starch from certain origins completely lost their granular structure during the enzyme treatment...

  16. Polycaprolactone/starch composite: Fabrication, structure, properties, and applications.

    Science.gov (United States)

    Ali Akbari Ghavimi, Soheila; Ebrahimzadeh, Mohammad H; Solati-Hashjin, Mehran; Abu Osman, Noor Azuan

    2015-07-01

    Interests in the use of biodegradable polymers as biomaterials have grown. Among the different polymeric composites currently available, the blend of starch and polycaprolactone (PCL) has received the most attention since the 1980s. Novamont is the first company that manufactured a PCL/starch (SPCL) composite under the trademark Mater-Bi®. The properties of PCL (a synthetic, hydrophobic, flexible, expensive polymer with a low degradation rate) and starch (a natural, hydrophilic, stiff, abundant polymer with a high degradation rate) blends are interesting because of the composite components have completely different structures and characteristics. PCL can adjust humidity sensitivity of starch as a biomaterial; while starch can enhance the low biodegradation rate of PCL. Thus, by appropriate blending, SPCL can overcome important limitations of both PCL and starch components and promote controllable behavior in terms of mechanical properties and degradation which make it suitable for many biomedical applications. This article reviewed the different fabrication and modification methods of the SPCL composite; different properties such as structural, physical, and chemical as well as degradation behavior; and different applications as biomaterials. © 2014 Wiley Periodicals, Inc.

  17. Genetic Engineering of Cereal Grains with Starch Consisting of More Than 99% Amylase

    DEFF Research Database (Denmark)

    Hebelstrup, Kim; Carciofi, Massimiliano; Blennow, Andreas

    2013-01-01

    that is resistant to enzymatic degradation, even when gelatinized by cooking. The barley plants producing the grains had a moderate yield loss of 25% in comparison with other barley plants of the same cultivar. We believe that the method can be applied to produce amylose-only starch in other cereal crops including......Numerous textbooks tell us that plant starches are a mix of two starch types: amylopectin and amylose. We recently succeeded in engineering a cereal crop – a barley line – producing grain starch consisting of more than 99% amylose1. This amylose-only starch contains a high residual fraction...

  18. The Research on Thermal Properties and Hydrophobility of the Native Starch/hydrolysis Starch Blends with Treated CaCO3 Powder

    Science.gov (United States)

    Liu, Chia-I.; Huang, Chi-Yuan

    2008-08-01

    In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60° to 95° when 15wt% treated CaCO3 was added. Treated CaCO3 was confirmed to improve the hydrophobility of starch blends effectively.

  19. THE RESEARCH ON THERMAL PROPERTIES AND HYDROPHOBILITY OF THE NATIVE STARCH/HYDROLYSIS STARCH BLENDS WITH TREATED CaCO3 POWDER

    International Nuclear Information System (INIS)

    Liu, C.-I; Huang, C.-Y.

    2008-01-01

    In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO 3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO 3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60 deg. to 95 deg. when 15wt% treated CaCO 3 was added. Treated CaCO 3 was confirmed to improve the hydrophobility of starch blends effectively

  20. Potato starch synthases

    NARCIS (Netherlands)

    Nazarian-Firouzabadi, Farhad; Visser, Richard G.F.

    2017-01-01

    Starch, a very compact form of glucose units, is the most abundant form of storage polyglucan in nature. The starch synthesis pathway is among the central biochemical pathways, however, our understanding of this important pathway regarding genetic elements controlling this pathway, is still

  1. Chlorophyll and starch assays

    OpenAIRE

    sprotocols

    2015-01-01

    Chlorophyll, starch, and sugar contents are good indicators of growth vigor in plants. To measure the chlorophyll content, we used a modified protocol (1,2). The starch content was determined using iodine staining (3) and enzymatic reactions (4-6).

  2. Lytic polysaccharide monooxygenases and other oxidative enzymes are abundantly secreted by Aspergillus nidulans grown on different starches

    DEFF Research Database (Denmark)

    Nekiunaite, Laura; Arntzen, Magnus Ø.; Svensson, Birte

    2016-01-01

    Starch is the second most abundant plant-derived biomass and a major feedstock in non-food industrial applications and first generation biofuel production. In contrast to lignocellulose, detailed insight into fungal degradation of starch is currently lacking. This study explores the secretomes...... of Aspergillus nidulans grown on cereal starches from wheat and high-amylose (HA) maize, as well as legume starch from pea for 5 days. Aspergillus nidulans grew efficiently on cereal starches, whereas growth on pea starch was poor. The secretomes at days 3-5 were starch-type dependent as also reflected...

  3. Insights into the multi-scale structure and digestibility of heat-moisture treated rice starch.

    Science.gov (United States)

    Wang, Hongwei; Liu, Yufan; Chen, Ling; Li, Xiaoxi; Wang, Jun; Xie, Fengwei

    2018-03-01

    The digestibility and structural changes of rice starch induced by heat-moisture treatment (HMT) were investigated, and the relationships among the moisture content-starch structure-starch digestibility were revealed. HMT could simultaneously disorder and reassemble the rice starch molecules across multi-scale lengths and convert some fractions of rapidly-digestible starch (RDS) into slowly-digestible starch (SDS) and resistant starch (RS). In particular, the HMT rice starch with less than 30% moisture content showed a higher SDS+RS content (25.0%). During HMT, SDS and RS were preferably formed by the degraded starch molecules with M w between 4×10 5 and 4×10 6 g/mol, single helices and amylose-lipids complexes that were formed by degraded starch chains with higher thermal stability and crystalline lamellae with greater thicknesses. Thus, our research suggests a potential approach using HMT to control the digestion of starch products with desired digestibility. Copyright © 2017. Published by Elsevier Ltd.

  4. Black leaf streak disease affects starch metabolism in banana fruit.

    Science.gov (United States)

    Saraiva, Lorenzo de Amorim; Castelan, Florence Polegato; Shitakubo, Renata; Hassimotto, Neuza Mariko Aymoto; Purgatto, Eduardo; Chillet, Marc; Cordenunsi, Beatriz Rosana

    2013-06-12

    Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots.

  5. Simultaneous production of raw starch degrading highly ...

    African Journals Online (AJOL)

    The widely used thermostable amylases were produced long time ago from Bacillus genus. Although, lactic acid bacteria (LAB) fermentation presents several advantages including the reduction of growth of pathogenic microorganisms, no study has yet reported thermostable amylases from lactic acid bacteria. An amylolytic ...

  6. Nanosilver: A Catalyst in Enzymatic Hydrolysis of Starch

    Directory of Open Access Journals (Sweden)

    Falkowska Marta

    2014-09-01

    Full Text Available Silver nanoparticles are widely used, because of their antimicrobial properties. In this paper, the rate of starch digestion in the presence of nanocatalyst was compared with the rate of reaction without nanosilver. The rate of enzymatic degradation of starch was found to be increased in the presence of silver nanoparticles. It is considered that α-amylase was immobilized onto the surface of nanoparticles.

  7. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  8. Preparation and characterization of biodegradable polyhydroxybutyrate-co-hydroxyvalerate/polyethylene glycol-based microspheres.

    Science.gov (United States)

    Monnier, Alexandre; Rombouts, Charlotte; Kouider, Dania; About, Imad; Fessi, Hatem; Sheibat-Othman, Nida

    2016-11-20

    The in vivo effectiveness of biomolecules may be limited by their rapid diffusion in the body and short half-life time. Encapsulation of these biomolecules allows protecting them against degradation and ensuring a controlled release over time. In this work, the production of polyhydroxybutyrate-co-hydroxyvalerate/polyethylene glycol-based microspheres loaded with heparin by double emulsion-solvent evaporation is investigated. Significant improvements are achieved after blending PHB-HV microspheres with PEG. First of all, an important decrease of the initial burst effect is ensured. Moreover, lower degradation of the microspheres is observed after 30days in the release medium. Finally, the release rate could be controlled using different PEG molecular weights and concentrations. A toxic effect of PHB-HV 30% PEG 1100gmol -1 microspheres is observed whereas PHB-HV and PHB-HV 30% PEG 10,000gmol -1 microspheres are not toxic. These microspheres seem to be most suited for further tissue engineering applications. The effectiveness of direct PEG blending to PHB-HV is proved, limiting the use of chemical reagents for PHB-HV/PEG copolymer synthesis and steps for chemical reagents removal from the copolymer. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A new generation of starch products as excipient in pharmaceutical tablets .1. Preparation and binding properties of high surface area potato starch products

    NARCIS (Netherlands)

    Wierik, GHPT; ArendsScholte, AW; Eissens, AC; Lerk, CF

    1996-01-01

    A new pharmaceutical excipient with a high binding capacity was prepared from potato starch by enzymatic degradation, followed by suitable dehydration of the precipitated and filtered retrograded starch to produce high specific surface area products. Thermal dehydration methods like drying at room

  10. A new generation of starch products as excipient in pharmaceutical tablets .2. High surface area retrograded pregelatinized potato starch products in sustained-release tablets

    NARCIS (Netherlands)

    TeWierik, GHP; Eissens, AC; ArendsScholte, AW; Lerk, CF

    1997-01-01

    A new linear short-chain starch product was prepared by gelatinization of potato starch followed by enzymatic degradation, precipitation (retrogradation) and filtration. A high specific surface area was subsequently created by washing with ethanol or acetone or freeze-drying. Tablets compressed from

  11. Characterization of starch nanoparticles

    Science.gov (United States)

    Szymońska, J.; Targosz-Korecka, M.; Krok, F.

    2009-01-01

    Nanomaterials already attract great interest because of their potential applications in technology, food science and medicine. Biomaterials are biodegradable and quite abundant in nature, so they are favoured over synthetic polymer based materials. Starch as a nontoxic, cheap and renewable raw material is particularly suitable for preparation of nanoparticles. In the paper, the structure and some physicochemical properties of potato and cassava starch particles of the size between 50 to 100 nm, obtained by mechanical treatment of native starch, were presented. We demonstrated, with the aim of the Scanning Electron Microscopy (SEM) and the non-contact Atomic Force Microscopy (nc-AFM), that the shape and dimensions of the obtained nanoparticles both potato and cassava starch fit the blocklets - previously proposed as basic structural features of native starch granules. This observation was supported by aqueous solubility and swelling power of the particles as well as their iodine binding capacity similar to those for amylopectin-type short branched polysaccharide species. Obtained results indicated that glycosidic bonds of the branch linkage points in the granule amorphous lamellae might be broken during the applied mechanical treatment. Thus the released amylopectin clusters could escape out of the granules. The starch nanoparticles, for their properties qualitatively different from those of native starch granules, could be utilized in new applications.

  12. Future cereal starch bioengineering

    DEFF Research Database (Denmark)

    Blennow, Andreas; Jensen, Susanne Langgård; Shaik, Shahnoor Sultana

    2013-01-01

    in combination to further functionalize or stabilize the starch polymers. Importantly, such products can be multifunctional in the sense of combined food/material or food/pharma purposes, for example, edible plastics, shape memory materials, and cycloamylose carriers and stabilizers for diverse bioactives......The importance of cereal starch production worldwide cannot be overrated. However, the qualities and resulting values of existing raw and processed starch do not fully meet future demands for environmentally friendly production of renewable, advanced biomaterials, functional foods, and biomedical...

  13. microspheres-encapsulated vaccine preparation against ...

    African Journals Online (AJOL)

    PLGA) microspheres of coated in fish vaccine formulations. In this study, we prepared Pseudomonas bacteria widowed raise PLGA microspheres vaccine by double emulsion evaporation maltophilia. It was prepared to support the completion of the ...

  14. Enhancing saccharification of cassava stems by starch hydrolysis prior to pretreatment

    OpenAIRE

    Martín, Carlos; Wei, Maogui; Xiong, Shaojun; Jönsson, Leif J.

    2017-01-01

    Chemical characterization of cassava stems from different origin revealed that glucans accounted for 54-63% of the dry weight, whereas 35-67% of these glucans consisted of starch. The cassava stems were subjected to a saccharification study including starch hydrolysis, pretreatment with either sulfuric acid or 1-ethyl-3-methylimidazolium acetate ([Emim]OAc), and enzymatic hydrolysis of cellulose. Starch hydrolysis prior to pretreatment decreased sugar degradation, improved enzymatic convertib...

  15. Structure of potato starch

    DEFF Research Database (Denmark)

    Bertoft, Eric; Blennow, Andreas

    2016-01-01

    Potato starch granules consist primarily of two tightly packed polysaccharides, amylose and amylopectin. Amylose, which amount for 20-30%, is the principal linear component, but a fraction is in fact slightly branched. Amylopectin is typically the major component and is extensively branched......, containing short chains with an average length of 22-25 glucosyl residues. The branching pattern is not well known, but branch point clustering guides chains to determine the overall starch granule architecture and starch functionality. The clusters consist of 5-10 grouped short chains, which...... are interconnected by long chains with more than 36 residues. The clusters consist of still smaller, very tightly branched building blocks. The clusters direct the semicrystalline structures found inside the starch granules. The crystals, which are ~5.2. nm thick, contain double helices formed from the external...

  16. Enzymatic modification of starch

    DEFF Research Database (Denmark)

    Jensen, Susanne Langgård

    In the food industry approaches for using bioengineering are investigated as alternatives to conventional chemical and physical starch modification techniques in development of starches with specific properties. Enzyme-assisted post-harvest modification is an interesting approach to this, since...... it is considered a clean and energy saving technology. This thesis aimed to investigate the effect of using reaction conditions, simulating an industrial process, for enzymatic treatment of starch with branching enzyme (BE) from Rhodothermus obamensis. Thus treatements were conducted at 70°C using very high...... substrate concentration (30-40% dry matter (DM)) and high enzyme activity (750-2250 BE units (BEU)/g sample). Starches from various botanical sources, representing a broad range of properties, were used as substrates. The effects of the used conditions on the BE-reaction were evaluated by characterization...

  17. Environmental impact assessment of six starch plastics focusing on wastewater-derived starch and additives

    NARCIS (Netherlands)

    Broeren, Martijn L.M.; Kuling, Lody; Worrell, Ernst; Shen, Li

    2017-01-01

    Starch plastics are developed for their biobased origin and potential biodegradability. To assist the development of sustainable starch plastics, this paper quantifies the environmental impacts of starch plastics produced from either virgin starch or starch reclaimed from wastewater. A

  18. Mammalian mucosal α-glucosidases coordinate with α-amylase in the initial starch hydrolysis stage to have a role in starch digestion beyond glucogenesis.

    Directory of Open Access Journals (Sweden)

    Sushil Dhital

    Full Text Available Starch digestion in the human body is typically viewed in a sequential manner beginning with α-amylase and followed by α-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal α-glucosidases act with α-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly α-amylase, and intestinal extract containing a combination of α-amylase and mucosal α-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. α-Amylase combined with the mucosal α-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph, and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal α-glucosidases was observed which shows that these enzymes may work either independently or together with α-amylase to digest starch. Thus, mucosal α-glucosidases can have a synergistic effect with α-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary

  19. Mammalian mucosal α-glucosidases coordinate with α-amylase in the initial starch hydrolysis stage to have a role in starch digestion beyond glucogenesis.

    Science.gov (United States)

    Dhital, Sushil; Lin, Amy Hui-Mei; Hamaker, Bruce R; Gidley, Michael J; Muniandy, Anbuhkani

    2013-01-01

    Starch digestion in the human body is typically viewed in a sequential manner beginning with α-amylase and followed by α-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal α-glucosidases act with α-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly α-amylase, and intestinal extract containing a combination of α-amylase and mucosal α-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. α-Amylase combined with the mucosal α-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph), and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal α-glucosidases was observed which shows that these enzymes may work either independently or together with α-amylase to digest starch. Thus, mucosal α-glucosidases can have a synergistic effect with α-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary glucogenesis function.

  20. Mammalian Mucosal α-Glucosidases Coordinate with α-Amylase in the Initial Starch Hydrolysis Stage to Have a Role in Starch Digestion beyond Glucogenesis

    Science.gov (United States)

    Dhital, Sushil; Lin, Amy Hui-Mei; Hamaker, Bruce R.; Gidley, Michael J.; Muniandy, Anbuhkani

    2013-01-01

    Starch digestion in the human body is typically viewed in a sequential manner beginning with α-amylase and followed by α-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal α-glucosidases act with α-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly α-amylase, and intestinal extract containing a combination of α-amylase and mucosal α-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. α-Amylase combined with the mucosal α-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph), and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal α-glucosidases was observed which shows that these enzymes may work either independently or together with α-amylase to digest starch. Thus, mucosal α-glucosidases can have a synergistic effect with α-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary glucogenesis function. PMID

  1. Effect of Ultrasound on Physicochemical Properties of Wheat Starch

    Directory of Open Access Journals (Sweden)

    Mahsa Majzoobi

    2014-04-01

    Full Text Available Application of ultrasound process is growing in food industry for different purposes including homogenization, extraction, blanching and removal of microorganisms, etc. On the other hand, starch is a natural polymer which exists in many foods or added into the food as an additive. Therefore, determination of the effects of ultrasound on starch characteristics can be useful in interpretation of the properties of starch-containing products. The main aim of this study was to determine the physicochemical changes of wheat starch treated by ultrasound waves. Therefore, an ultrasound probe device was used which ran at 20 kHz, 100 W and 22°C. Starch suspension in distilled water (30% w/w was prepared and treated with ultrasound for 5, 10, 15 and 20 min. The results showed that increases in processing duration led to increases in water solubility of starch, water absorption and gel clarity (as determined by spectrophotometry. Starch intrinsic viscosity as measured using an Ostwald U-tube showed lower intrinsic viscosity with increases in ultrasound time. Gel strength of the samples as determined using a texture analyzer was reduced by longer processing time. The scanning electron microscopy revealed that increasing the duration time of the ultrasound treatment could produce some cracks and spots on the surface of the granules. In total, it was concluded that the ultrasound treatment resulted in some changes from the starch granular scale to molecular levels. Some of the starch molecules were degraded upon ultrasound processing. Such changes may be observed for the starch-containing foods treated with ultrasound and they are enhanced with increases in ultrasound time intervals.

  2. Gastroretentive Floating Microspheres of Silymarin: Preparation and ...

    African Journals Online (AJOL)

    Methods: Cellulose microspheres – formulated with hydroxylpropyl methylcellulose (HPMC) and ethyl cellulose (EC) – and Eudragit microspheres – formulated with Eudragit® S 100 (ES) and Eudragit® RL (ERL) - were prepared by an emulsion-solvent evaporation method. The floating microspheres were evaluated for flow ...

  3. Floating microspheres: a review

    Directory of Open Access Journals (Sweden)

    Jagtap Yogesh Mukund

    2012-03-01

    Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e

  4. TECHNOLOGY OF THERMOPLASTIC STARCH PRODUCTION

    Directory of Open Access Journals (Sweden)

    N. D. Lukin

    2015-01-01

    Full Text Available In recent years, the manufacturing of bio-recyclable polymer products, which production and consumption has become an efficient way to protect environment from solid wastes in different countries of the world. The issue of environmental protection becomes global and the rapid growth of synthetic plastics application in many industries is a serious concern. There is a important task to improve the quality, safety and durability of products as well as their utilization after the expiration period. One of the most acceptable ways to solve these issues is to produce biodegradable materials based on natural materials, which are not harmful for environment and human health. A very common and effective method to give biological degradability to synthetic polymers is to insert starch into polymer composition in combination with other ingredients.

  5. The adsorption of α-amylase on barley proteins affects the in vitro digestion of starch in barley flour.

    Science.gov (United States)

    Yu, Wenwen; Zou, Wei; Dhital, Sushil; Wu, Peng; Gidley, Michael J; Fox, Glen P; Gilbert, Robert G

    2018-02-15

    The conversion of barley starch to sugars is a complex enzymic process. Most previous work concerned the biotechnical aspect of in situ barley enzymes. However, the interactions among the macromolecular substrates and their effects on enzymic catalysis has been little examined. Here, we explore the mechanisms whereby interactions of protein and starch in barley flour affect the kinetics of enzymatic hydrolysis of starch in an in vitro system, using digestion rate data and structural analysis by confocal microscopy. The degradation kinetics of both uncooked barley flour and of purified starches are found to be two-step sequential processes. Barley proteins, especially the water-soluble component, are found to retard the digestion of starch degraded by α-amylase: the enzyme binds with water-insoluble protein and with starch granules, leading to reduced starch hydrolysis. These findings are of potential industrial value in both the brewing and food industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Digestion and Interaction of Starches with α-Amylases: I. Mutational analysis of Carbohydrate Binding Sites in barley. II. In Vitro Starch Digestion of Legumes

    DEFF Research Database (Denmark)

    Nielsen, Morten Munch

    2006-01-01

    the hydrolysis of internal 1,4-α-D-glucosidic bonds in starch and related polysaccharides. The present thesis concerns studies of two α-amylases: 1) secondary substrate binding sites in barley α-amylase 1 (AMY1), and 2) the involvement of anti-nutrients in in vitro digestion of starch in legumes by porcine......Starch is the primary energy storage of higher plants and an import nutrient for mammals, fungi and bacteria. The mobilization of starch is thus essential in both the germination of the barley grain and in human digestion of foods. α-Amylase (1,4-α-D-glucan glucanohydrolase, EC. 3.2.1.1) catalyzes...... pancreatic α-amylase. The degradation of insoluble polysaccharides by glycoside hydrolases is relative inefficient as the polysaccharide chains often are barely inaccessible to the active site of the enzymes. Many raw starch-degrading enzymes contain secondary carbohydrate binding sites on the catalytic...

  7. Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches.

    Science.gov (United States)

    Majzoobi, Mahsa; Beparva, Paniz

    2014-03-15

    The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties of native and cross-linked wheat starches were investigated prior and after gelatinization. These acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches decreased in the presence of the acids particularly after gelatinization. Water solubility increased while water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic and gummy when acids were added. These changes may indicate the degradation of the starch molecules by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties of both starches before and after gelatinization was greater than acetic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Fungal lytic polysaccharide monooxygenases bind starch and β-cyclodextrin similarly to amylolytic hydrolases

    DEFF Research Database (Denmark)

    Nekiunaite, Laura; Isaksen, Trine; Vaaje-Kolstad, Gustav

    2016-01-01

    , the clustering of CBM20s from starch-targeting LPMOs and hydrolases was in accord with taxonomy and did not correlate to appended catalytic activity. Altogether, these results demonstrate that the CBM20-binding scaffold is retained in the evolution of hydrolytic and oxidative starch-degrading activities....

  9. The effect of mono- and poly-organic acids on thermoformed starch-protein composites

    Science.gov (United States)

    Bioplastic materials derived from proteins and starch are often difficult to process in high throughput plastic polymer molders due to their high moisture content and low melt properties. Starch and protein materials degrade above 140 deg C, exhibiting discoloration and low mechanical strength. In t...

  10. Effect of citric acid concentration and hydrolysis time on physicochemical properties of sweet potato starches.

    Science.gov (United States)

    Surendra Babu, Ayenampudi; Parimalavalli, Ramanathan; Rudra, Shalini Gaur

    2015-09-01

    Physicochemical properties of citric acid treated sweet potato starches were investigated in the present study. Sweet potato starch was hydrolyzed using citric acid with different concentrations (1 and 5%) and time periods (1 and 11 h) at 45 °C and was denoted as citric acid treated starch (CTS1 to CTS4) based on their experimental conditions. The recovery yield of acid treated starches was above 85%. The CTS4 sample displayed the highest amylose (around 31%) and water holding capacity its melting temperature was 47.66 °C. The digestibility rate was slightly increased for 78.58% for the CTS3 and CTS4. The gel strength of acid modified starches ranged from 0.27 kg to 1.11 kg. RVA results of acid thinned starches confirmed a low viscosity profile. CTS3 starch illustrated lower enthalpy compared to all other modified starches. All starch samples exhibited a shear-thinning behavior. SEM analysis revealed that the extent of visible degradation was increased at higher hydrolysis time and acid concentration. The CTS3 satisfied the criteria required for starch to act as a fat mimetic. Overall results conveyed that the citric acid treatment of sweet potato starch with 5% acid concentration and 11h period was an ideal condition for the preparation of a fat replacer. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Preparation and properties of resistant starch from corn starch with ...

    African Journals Online (AJOL)

    amylase and pullulanase and followed by retrogradation, to prepare resistant starch. The properties of selected resistant starch (RS) samples were also investigated. The result showed that, appropriate amount (0.5 U/g) of thermostable á-amylase ...

  12. Temperature influence in crystallinity of polymer microspheres

    International Nuclear Information System (INIS)

    Rezende, Cristiane de P.; Novack, Katia M.

    2011-01-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  13. Glass transition of anhydrous starch by fast scanning calorimetry.

    Science.gov (United States)

    Monnier, Xavier; Maigret, Jean-Eudes; Lourdin, Denis; Saiter, Allisson

    2017-10-01

    By means of fast scanning calorimetry, the glass transition of anhydrous amorphous starch has been measured. With a scanning rate of 2000Ks -1 , thermal degradation of starch prior to the glass transition has been inhibited. To certify the glass transition measurement, structural relaxation of the glassy state has been investigated through physical aging as well as the concept of limiting fictive temperature. In both cases, characteristic enthalpy recovery peaks related to the structural relaxation of the glass have been observed. Thermal lag corrections based on the comparison of glass transition temperatures measured by means of differential and fast scanning calorimetry have been proposed. The complementary investigations give an anhydrous amorphous starch glass transition temperature of 312±7°C. This estimation correlates with previous extrapolation performed on hydrated starches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Synthesis and photocatalytic properties of different SnO2 microspheres on graphene oxide sheets

    Science.gov (United States)

    Wei, Jia; Xue, Shaolin; Xie, Pei; Zou, Rujia

    2016-07-01

    Different SnO2 microspheres like dandelions, silkworm cocoons and urchins have been synthesized on graphene oxide sheets (GOs) by hydrothermal method at 190 °C for 24 h. The morphologies, structures, chemical compositions and optical properties of the as-grown SnO2 microspheres on GOs (SMGs) were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), Raman spectra and UV-vis diffuse reflectance spectra (DRS) techniques. The results of XRD revealed that the as-grown SnO2 microspheres have tetragonal rutile structure. The results of Raman spectra, EDS, XRD, XPS and SEM showed that the SnO2 microspheres were grown on GOs and the average diameter of dandelion-like microsphere was about 1.5 μm. The formation mechanism of SnO2 microspheres grown on GOs was discussed. The photocatalytic activity of the SMGs composites was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The photocatalytic results showed that the dandelion-like SMGs exhibited a much better photocatalytic activity than those of smooth and rough SMGs.

  15. Electrospray synthesis and properties of hierarchically structured PLGA TIPS microspheres for use as controlled release technologies.

    Science.gov (United States)

    Malik, Salman A; Ng, Wing H; Bowen, James; Tang, Justin; Gomez, Alessandro; Kenyon, Anthony J; Day, Richard M

    2016-04-01

    Microsphere-based controlled release technologies have been utilized for the long-term delivery of proteins, peptides and antibiotics, although their synthesis poses substantial challenges owing to formulation complexities, lack of scalability, and cost. To address these shortcomings, we used the electrospray process as a reproducible, synthesis technique to manufacture highly porous (>94%) microspheres while maintaining control over particle structure and size. Here we report a successful formulation recipe used to generate spherical poly(lactic-co-glycolic) acid (PLGA) microspheres using the electrospray (ES) coupled with a novel thermally induced phase separation (TIPS) process with a tailored Liquid Nitrogen (LN2) collection scheme. We show how size, shape and porosity of resulting microspheres can be controlled by judiciously varying electrospray processing parameters and we demonstrate examples in which the particle size (and porosity) affect release kinetics. The effect of electrospray treatment on the particles and their physicochemical properties are characterized by scanning electron microscopy, confocal Raman microscopy, thermogravimetric analysis and mercury intrusion porosimetry. The microspheres manufactured here have successfully demonstrated long-term delivery (i.e. 1week) of an active agent, enabling sustained release of a dye with minimal physical degradation and have verified the potential of scalable electrospray technologies for an innovative TIPS-based microsphere production protocol. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Influence of nanoparticles on the properties of bionanocomposites from cassava starch

    International Nuclear Information System (INIS)

    Paglicawan, Marissa A.; Emolaga, Carlo S.; Navarro, Ma. Teresa V.; Celorico, Josefina; Basilia, Blessie A.

    2015-01-01

    Plastics are widely used packaging materials for food and non-food products due to their desirable material properties and low cost. However, the merits of plastic products have been overshadowed by its non-degradable nature, thereby leading to waste disposal problems. Because of the environmental problem, many researchers are facing to minimize non-degradable to biodegradable materials. Starch is one of the most promising natural polymers because of its inherent biodegradability, overwhelming abundance and its renewability. One of the abundant starch is cassava. The Manihot exculenta Crantz, is known as camoteng-kahoy or balinghoy in the Philippines. The production of thermoplastic starch (also known as plasticized starch or TPS) basically involves three essential components, namely: starch, plasticizer and thermomechanical energy. However, this material has high water solubility and may lose their mechanical properties in humid conditions. One of the possible ways to overcome this problem is through nanocomposite in which consist of a polymer matrix reinforced with nano-dimensional particles. This research involves the processing of cassava starch into thermoplastic starch for packaging application that can be biodegraded in soil or compostable after its usage. Thermoplastic starchs from cassava starch and different nanomaterials were processed by melt-blending method in a twin-screw extruder. The four nanofillers - nanoclay (NC), halloysite nanotube (HNT), nanozeolite (NZ), and nanocalcium carbonate (NCC) were incorporated into the starch matrix in a 3 phr concentration. The resulting biocomposites were characterized in terms of mechanical properties, morphology, thermal properties, moisture absorption, and crystallinity. The newly developed technology based on cassava starch/nano-scale particles nanocomposites upgrade the hdydrophylic and mechanical properties of starch based films. Homogeneously dispersing nanometer size materials, with high length

  17. Starch phosphorylation plays an important role in starch biosynthesis

    NARCIS (Netherlands)

    Xu, Xuan; Dees, Dianka; Dechesne, Annemarie; Huang, Xing Feng; Visser, Richard G.F.; Trindade, Luisa M.

    2017-01-01

    Starch phosphate esters are crucial in starch metabolism and render valuable functionality to starches for various industrial applications. A potato glucan, water dikinase (GWD1) was introduced in tubers of two different potato genetic backgrounds: an amylose-containing line Kardal and the

  18. New starch methodology to measure both soluble and insoluble starch

    Science.gov (United States)

    Starch is a natural sugarcane juice impurity that greatly influences raw sugar quality and affects factory and refinery processing. Since the advent of the USDA Starch Research method, the mechanisms in which starch concentration and physical form affects sugar crop processing, conversion, and end-g...

  19. Synthesis and photocatalytic properties of different SnO{sub 2} microspheres on graphene oxide sheets

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jia, E-mail: jojo.1125@hotmail.com [College of Science, Donghua University, Shanghai 201620 (China); Xue, Shaolin, E-mail: slxue@dhu.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); Xie, Pei, E-mail: peipeixie@sina.com [College of Science, Donghua University, Shanghai 201620 (China); Zou, Rujia, E-mail: rujiazou@dhu.edu.cn [College of Science, Donghua University, Shanghai 201620 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2016-07-15

    Highlights: • Different SnO{sub 2} microspheres were grown on GOs by hydrothermal method. • The morphology was influenced by volume ratio of ethanol and concentrations of precursor. • The shape of SnO{sub 2} microspheres looks like dandelion. • The photocatalytic property is strongly influenced by the SnO{sub 2} morphology on GOs. - Abstract: Different SnO{sub 2} microspheres like dandelions, silkworm cocoons and urchins have been synthesized on graphene oxide sheets (GOs) by hydrothermal method at 190 °C for 24 h. The morphologies, structures, chemical compositions and optical properties of the as-grown SnO{sub 2} microspheres on GOs (SMGs) were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), Raman spectra and UV–vis diffuse reflectance spectra (DRS) techniques. The results of XRD revealed that the as-grown SnO{sub 2} microspheres have tetragonal rutile structure. The results of Raman spectra, EDS, XRD, XPS and SEM showed that the SnO{sub 2} microspheres were grown on GOs and the average diameter of dandelion-like microsphere was about 1.5 μm. The formation mechanism of SnO{sub 2} microspheres grown on GOs was discussed. The photocatalytic activity of the SMGs composites was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The photocatalytic results showed that the dandelion-like SMGs exhibited a much better photocatalytic activity than those of smooth and rough SMGs.

  20. Synthesis and photocatalytic properties of different SnO2 microspheres on graphene oxide sheets

    International Nuclear Information System (INIS)

    Wei, Jia; Xue, Shaolin; Xie, Pei; Zou, Rujia

    2016-01-01

    Highlights: • Different SnO 2 microspheres were grown on GOs by hydrothermal method. • The morphology was influenced by volume ratio of ethanol and concentrations of precursor. • The shape of SnO 2 microspheres looks like dandelion. • The photocatalytic property is strongly influenced by the SnO 2 morphology on GOs. - Abstract: Different SnO 2 microspheres like dandelions, silkworm cocoons and urchins have been synthesized on graphene oxide sheets (GOs) by hydrothermal method at 190 °C for 24 h. The morphologies, structures, chemical compositions and optical properties of the as-grown SnO 2 microspheres on GOs (SMGs) were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), Raman spectra and UV–vis diffuse reflectance spectra (DRS) techniques. The results of XRD revealed that the as-grown SnO 2 microspheres have tetragonal rutile structure. The results of Raman spectra, EDS, XRD, XPS and SEM showed that the SnO 2 microspheres were grown on GOs and the average diameter of dandelion-like microsphere was about 1.5 μm. The formation mechanism of SnO 2 microspheres grown on GOs was discussed. The photocatalytic activity of the SMGs composites was evaluated by photocatalytic degradation of Rhodamine B (Rh B) aqueous solution under visible light irradiation. The photocatalytic results showed that the dandelion-like SMGs exhibited a much better photocatalytic activity than those of smooth and rough SMGs.

  1. Cereal bioengineering: Amylopectin-free and hyper-phosphorylated barley starch

    DEFF Research Database (Denmark)

    Carciofi, Massimiliano; Shaik, Shahnoor Sultana; Jensen, Susanne Langgård

    Barley lines producing grains with either amylopectin-free or hyper-phosphorylated starches were made by transgenic methods. Cereals producing these kind of starches have not been reported before. Amylopectin-free barley was generated by simultaneously silencing the three genes encoding the starch...... and T1) of transgenic grains was tenfold higher than from vector control and wild type grains. Amylose content was not affected in hyper-phosphorylated grains. Hyper-phosphorylated starch granules had several pores on the surfaces, similar to pores seen on enzymatically semi-degraded granules...

  2. Cereal bioengineering: Amylopectin-free and hyper-phosphorylated barley starch

    DEFF Research Database (Denmark)

    Carciofi, Massimiliano; Shaik, Shahnoor Sultana; Jensen, Susanne Langgård

    2011-01-01

    Barley lines producing grains with either amylopectin-free or hyper-phosphorylated starches were made by transgenic methods. Cereals producing these kind of starches have not been reported before. Amylopectin-free barley was generated by simultaneously silencing the three genes encoding the starch...... and T1) of transgenic grains was tenfold higher than from vector control and wild type grains. Amylose content was not affected in hyper-phosphorylated grains. Hyper-phosphorylated starch granules had several pores on the surfaces, similar to pores seen on enzymatically semi-degraded granules...

  3. Anti-tumor necrosis factor-alpha-loaded microspheres as a prospective novel treatment for Crohn's disease fistulae.

    Science.gov (United States)

    Foong, Keen Shawn; Patel, Rishni; Forbes, Alastair; Day, Richard M

    2010-10-01

    Antibodies to tumor necrosis factor alpha (TNF-α) have been successful in treating perianal fistulae in Crohn's disease, but current modes of delivery are limited. Microspheres are currently being assessed as scaffolds for tissue engineering and drug delivery devices. The aim of this study was to produce anti-TNF-α antibody-encapsulated microspheres using thermally induced phase separation (TIPS) and to characterize their behavior. Anti-TNF-α antibody was encapsulated into the microspheres (100 mg infliximab/g poly[lactide-co-glycolide] w/w) using a novel technique combining a vibration encapsulator unit with a TIPS process, using either lyophilized particulate antibody or an aqueous solution of antibody. Microspheres were incubated in phosphate-buffered saline for collection of supernatant and assessment of degradation. The amount and biological activity of the encapsulated antibody released from the microspheres was assessed by enzyme-linked immunosorbent assay and its ability to neutralize recombinant human (rh)TNF-α in vitro with a cytotoxicity assay. An in vitro wound scratch assay was used to assess the effect of released antibody on fibroblast migration. Ultrastructural characteristics of the different microspheres were characterized by scanning electron microscopy. Highly porous microspheres released anti-TNF-α antibody under zero-order kinetics and inhibited the cytotoxic activity of rhTNF-α, producing a significant increase in cell viability compared with cells treated with rhTNF-α alone. This effect was most pronounced with microspheres fabricated by blending lyophilized particulate anti-TNF-α antibody into the polymer solution, which also significantly reduced the release of lactate dehydrogenase. Anti-TNF-α antibody encapsulated into highly porous microspheres was released in a controlled manner and exhibited biological activity against TNF-α. The technique used to produce TIPS microspheres is rapid and provides high encapsulation efficiency

  4. Granule size affects substitution on amylopectin populations in potato and sweet potato starches

    NARCIS (Netherlands)

    Chen, Z.; Huang, J.; Suurs, P.; Schols, H.A.; Voragen, A.G.J.

    2005-01-01

    Specific enzymatic degradation in combination with chromatographic and spectrometric techniques was used to understand acetyl group distribution over the amylopectin populations of differently sized granule fractions from potato and sweet potato starches. The hydrolysates obtained after ¿-amylase,

  5. Radiation processing of starch

    International Nuclear Information System (INIS)

    Kamaruddin Hashim

    2008-01-01

    Starch is a polysaccharide material and generally, it is non-toxic, biocompatible and biodegradable. It mainly use as foodstuff, food additives, production of sugar and flavouring. Sago palm with scientific name Genus Metroxylon belonging to family Palmae is an important resource in the production of sago starch in Malaysia. Nearly 90% of sago planting areas is found in Sarawak State of Malaysia. It can easily grow under the harsh swampy environment. The sago starch content 4% polyphenol, which is an active compound with antioxidant property that has potential benefit in health and skin care applications. Renewal resources and environmental friendly of natural polymer reason for the researcher to explore the potential of this material in order to improve our quality of live. (author)

  6. Preparation and evaluation of a novel bioactive glass/lysozyme/PLGA composite microsphere.

    Science.gov (United States)

    Liu, Hongfei; Shi, Shuangshuang; Cao, Jin; Ji, Lijun; He, Yan; Xi, Jumei

    2015-03-01

    The objective of this study was to fabricate a novel nano-bioceramics incorporated lysozyme poly (d, l-lactide-co-glycolide) (PLGA) microsphere. The nano-bioceramics was used as a biodegradable and sustained-release antacid to stabilize the lysozyme in the drug release process. First, the nano-bioceramics were prepared by sol-gel method, and then were characterized by energy dispersive X-ray analysis, dynamic light scattering and in vitro degradation test. Second, the lysozyme PLGA microsphere incorporated with nano-bioceramic was fabricated by the S/W/O/W emulsion solvent evaporation method. The microsphere was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and UV circular dichroism (UV CD). Finally the in vitro drug release and bioactivity test was carried out. The composition of the nano-bioceramics was 58% SiO2, 36% CaO, 6% P2O5, and the average particle size was 295 nm. The nano-bioceramics incorporated lysozyme PLGA microspheres were prepared by the multi-emulsion method. The SEM results showed that the bioceramics was uniformly distributed in the PLGA microsphere. Results from in vitro lysozyme release test exhibited a prolonged release time for 1month. The FTIR and UVCD results suggested that the lysozyme in the drug release process had a similar secondary structure conformation to the native one. The Micrococcus lysodeikticus test showed that the microspheres incorporated with bioceramics provided long-term protein stability against the acidic environment resulted from PLGA's degradates and more than 90% of the lysozyme released over the 1 month period was preserved in a bioactive form. A novel bioceramics incorporated lysozyme PLGA microsphere was prepared with potentials for sustained protein release formulation.

  7. Prebiotic properties of potato starch dextrins.

    Science.gov (United States)

    Barczyńska, Renata; Śliżewska, Katarzyna; Libudzisz, Zdzisława; Kapuśniak, Kamila; Kapuśniak, Janusz

    2015-09-08

    The objective of the present study was to compare the prebiotic properties of starch dextrins, that is, resistant dextrins obtained from potato starch in the process of simultaneous thermolysis and chemical modification, which were selected based on previous research. Both prepared dextrins met the definition criterion of dietary fiber and also the basic prebiotic criterion - they were not degraded by the digestive enzymes of the initial sections of the gastrointestinal tract. The growth of probiotic lactobacilli and bifidobacteria, as well as Escherichia coli, Enterococcus, Bacteroides, and Clostridium strains isolated from feces of healthy people, showed that both studied dextrins were utilized as a source of assimilable carbon and energy by the strains. Furthermore, better growth (higher numbers of cells) counts of probiotic bacteria than those of fecal isolates indicated that the studied resistant dextrins showed a selective effect. Both dextrins might be considered as substances with prebiotic properties due to their chemical and physical properties and selectivity towards the studied probiotic bacterial strains.

  8. Hydroxyethyl starch in sepsis

    DEFF Research Database (Denmark)

    Haase, Nicolai Rosenkrantz Segelcke

    2014-01-01

    BACKGROUND: Hydroxyethyl starch (HES) is a colloid that has been widely used for fluid resuscitation for decades. The newest generation of HES, tetrastarch, was believed to provide an efficient volume expansion without causing the side effects observed with former HES solutions. However, this bel......BACKGROUND: Hydroxyethyl starch (HES) is a colloid that has been widely used for fluid resuscitation for decades. The newest generation of HES, tetrastarch, was believed to provide an efficient volume expansion without causing the side effects observed with former HES solutions. However...

  9. The development of non-toxic ionic-crosslinked chitosan-based microspheres as carriers for the controlled release of silk sericin.

    Science.gov (United States)

    Aramwit, Pornanong; Ekasit, Sanong; Yamdech, Rungnapha

    2015-10-01

    Silk sericin is recently shown to possess various biological activities for biomedical applications. While various sericin carriers were developed for drug delivery system, very few researches considered sericin as a bioactive molecule itself. In this study, sericin incorporated in the chitosan-based microspheres was introduced as a bioactive molecule and bioactive carrier at the same time. The chitosan/sericin (CH/SS) microspheres at different composition (80/20, 70/30, 60/40, and 50/50) were successfully fabricated using anhydroustri-polyphosphate (TPP) as a polyanionic crosslinker. The microspheres with an average size of 1-4 μm and narrow size distribution were obtained. From FT-IR spectra, the presence of both chitosan and sericin in the microspheres confirmed the occurrence of ionic interaction that crosslink them within the microspheres. We also found that the CH/SS microspheres prepared at 50/50 could encapsulate sericin at the highest percentage (37.28%) and release sericin in the most sustained behavior, possibly due to the strong ionic interaction of the positively charged chitosan and the negatively charged sericin. On the other hand, the composition of CH/SS had no effect on the degradation rate of microspheres. All microspheres continuously degraded and remained around 20% after 14 days of enzymatic degradation. This explained that the ionic crosslinkings between chitosan and sericin could be demolished by the enzyme and hydrolysis. Furthermore, we have verified that all CH/SS microspheres at any concentrations showed non-toxicity to L929 mouse fibroblast cells. Therefore, we suggested that the non-toxic ionic-crosslinked CH/SS microspheres could be incorporated in wound dressing material to achieve the sustained release of sericin for accelerated wound healing.

  10. Chitosan microspheres in novel drug delivery systems.

    Science.gov (United States)

    Mitra, Analava; Dey, Baishakhi

    2011-07-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

  11. Additional synthesis of starch from sucrose in leaves of arabidopsis in the light

    International Nuclear Information System (INIS)

    Keerberg, O.; Ivanova, H.; Keerberg, H.; Paernik, T.

    2005-01-01

    Full text: Accumulating during daytime starch is converted in the night into sucrose and consumed in respiratory, biosynthetic and transport processes. However in the light the degradation and conversion of starch are blocked. In pulse chase experiments with wild type plants and starchless mutants pgm or adg1 of arabidopsis an increase of starch radioactivity during chase in nonradioactive medium in the light was detected. These findings suggest that starch was additionally synthesized from labeled cytosolic soluble photosynthates, preferentially from sucrose. Radiogasometric studies of gas exchange have revealed that sucrose is consumed also in photorespiratory decarboxylations. To be involved in photorespiration the products of sucrose degradation must be transported from cytosol into chloroplast. We presume that derived from sucrose hexoses are transported into chloroplast by hexose transporter and phosphorylated there in hexokinase reaction. The phosphorylated hexoses may be consumed either for additional synthesis of starch or incorporated into the reductive pentose phosphate cycle and, via this cycle, into the glycolate cycle. (author)

  12. Heterologous expression of two Arabidopsis starch dikinases in potato

    NARCIS (Netherlands)

    Xu, Xuan; Dees, Dianka; Huang, Xing Feng; Visser, Richard G.F.; Trindade, Luisa M.

    2018-01-01

    Starch phosphate esters influence physiochemical properties of starch granules that are essential both for starch metabolism and industrial use of starches. To modify properties of potato starch and understand the effect of starch phosphorylation on starch metabolism in storage starch, the starch

  13. Preparing microspheres of actinide nitrides from carbon containing oxide sols

    International Nuclear Information System (INIS)

    Triggiani, L.V.

    1975-01-01

    A process is given for preparing uranium nitride, uranium oxynitride, and uranium carboxynitride microspheres and the microspheres as compositions of matter. The microspheres are prepared from carbide sols by reduction and nitriding steps. (Official Gazette)

  14. Evaluation of Starch Biodegradable Plastics Derived from Cassava ...

    African Journals Online (AJOL)

    BSN

    Abstract. Starch derived from two cassava cultivars, one with high amylose (TMS 92/0325) and the other with high amylopectin contents (TMS 91/02324), were screened for their ability to produce biodegradable plastics using different compositions of plasticizers and other materials. The rate of degradation of the bioplastics ...

  15. Caladium bicolor and wild Dioscorea dumetorum starches as dual ...

    African Journals Online (AJOL)

    Increased density of the composite with time after being buried for a total of 12 weeks in composting environment is an evidence of the degradation of LDPE which may be linked to an initial breakdown of starch by microorganism in the soil which probably give rise to diffusion of unsaturated lipids into the porous polymer ...

  16. Evaluation of Starch Biodegradable Plastics Derived from Cassava ...

    African Journals Online (AJOL)

    Starch derived from two cassava cultivars, one with high amylose (TMS 92/0325) and the other with high amylopectin contents (TMS 91/02324), were screened for their ability to produce biodegradable plastics using different compositions of plasticizers and other materials. The rate of degradation of the bioplastics produced ...

  17. Oligosaccharide and Substrate Binding in the Starch Debranching Enzyme Barley Limit Dextrinase

    DEFF Research Database (Denmark)

    Møller, Marie Sofie; Windahl, Michael Skovbo; Sim, Lyann

    2015-01-01

    Complete hydrolytic degradation of starch requires hydrolysis of both the α-1,4- and α-1,6-glucosidic bonds in amylopectin. Limit dextrinase (LD) is the only endogenous barley enzyme capable of hydrolyzing the α-1,6-glucosidic bond during seed germination, and impaired LD activity inevitably...... reduces the maltose and glucose yields from starch degradation. Crystal structures of barley LD and active-site mutants with natural substrates, products and substrate analogues were sought to better understand the facets of LD-substrate interactions that αconfine high activity of LD to branched...... starch synthesis....

  18. Hydroxyethyl starch for resuscitation

    DEFF Research Database (Denmark)

    Haase, Nicolai; Perner, Anders

    2013-01-01

    PURPOSE OF REVIEW: Resuscitation with hydroxyethyl starch (HES) is controversial. In this review, we will present the current evidence for the use of HES solutions including data from recent high-quality randomized clinical trials. RECENT FINDINGS: Meta-analyses of HES vs. control fluids show clear...

  19. Resistant starch in cassava products

    Directory of Open Access Journals (Sweden)

    Bruna Letícia Buzati Pereira

    2014-06-01

    Full Text Available Found in different foods, starch is the most important source of carbohydrates in the diet. Some factors present in starchy foods influence the rate at which the starch is hydrolyzed and absorbed in vivo. Due the importance of cassava products in Brazilian diet, the objective of this study was to analyze total starch, resistant starch, and digestible starch contents in commercial cassava products. Thirty three commercial cassava products from different brands, classifications, and origin were analyzed. The method used for determination of resistant starch consisted of an enzymatic process to calculate the final content of resistant starch considering the concentration of glucose released and analyzed. The results showed significant differences between the products. Among the flours and seasoned flours analyzed, the highest levels of resistant starch were observed in the flour from Bahia state (2.21% and the seasoned flour from Paraná state (1.93%. Starch, tapioca, and sago showed levels of resistant starch ranging from 0.56 to 1.1%. The cassava products analyzed can be considered good sources of resistant starch; which make them beneficial products to the gastrointestinal tract.

  20. Chitosan Microspheres as Radiolabeled Delivery Devices

    International Nuclear Information System (INIS)

    Permtermsin, Chalermsin; Ngamprayad, Tippanan; Phumkhem, Sudkanung; Srinuttrakul, Wannee; Kewsuwan, Prartana

    2007-08-01

    Full text: This study optimized conditions for preparing, characterizing, radiolabeled of chitosan microspheres and the biodistribution of 99mTc-Chitosan microspheres after intravenous administration. Particle size distribution of the microspheres was determined by light scattering. Zeta potential was studied by dynamic light scattering and electrophoresis technique. Biodistribution studies were performed by radiolabeling using 99mTc. The results shown that geometric mean diameter of the microspheres was found to be 77.26?1.96 ?m. Microsphere surface charge of chitosan microspheres was positive charge and zeta potential was 25.80 ? 0.46 mV. The labeling efficiency for this condition was more than 95% and under this condition was stable for at least 6 h. Radioactivity

  1. Structure and properties of pregelatinized cassava starch/kaolin composites

    International Nuclear Information System (INIS)

    Kaewtatip, Kaewta; Tanrattanakul, Varaporn

    2012-01-01

    Highlights: ► Pregelatinized starch/kaolin composites were prepared using compression molding. ► The tensile strengths of the composites were higher than for thermoplastic starch. ► Degradation temperatures of the composites were higher than for thermoplastic starch. ► The retrogradation behavior of the composites was hindered by kaolin. -- Abstract: Pregelatinized cassava starch/kaolin composites were prepared using compression molding. The morphology of the fractured surfaces, retrogradation behavior, thermal decomposition temperatures and mechanical properties of the composites were investigated using scanning election microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile testing, respectively. The tensile strengths and thermal degradation temperatures of the composites were higher than for thermoplastic starch (TPS). The retrogradation behavior of the composites was hindered by kaolin. The water absorption was measured after aging for 12 and 45 days at a relative humidity (RH) of 15% and 55%. It indicated that all the composites displayed lower water absorption values than TPS.

  2. The effect of some processing conditions on the characteristics of biodegradable microspheres obtained by an emulsion solvent evaporation process

    Directory of Open Access Journals (Sweden)

    J. L. Maia

    2004-01-01

    Full Text Available Unloaded microspheres were prepared from polyhydroxybutyrate (PHB and polyhydroxybutyrate-co-valerate (PHB-HV polymers using an oil-in-water emulsion solvent evaporation method. The study was conducted to evaluate how the polymer and some process parameters affect properties of the final microspheres such as particle size, superficial area, zeta potential, surface morphology and microsphere degradation. The variables included surfactant concentration in the emulsion water phase and solvent composition. From the results, it was found that the parameters affecting microsphere size the most were surfactant concentration in the emulsion water phase and solvent composition. Properties such as zeta potential, surface area and surface morphology remained pratically unchanged over the range of the processing conditions studied here.

  3. Filling Porous Microspheres With Magnetic Material

    Science.gov (United States)

    Chang, Manchium; Colvin, Michael S.

    1990-01-01

    New process produces magnetic microspheres with controllable sizes, compositions, and properties for use in medical diagnostic tests, biological research, and chemical processes. Paramagnetic microspheres also made with process. Porous plastic microspheres prepared by polymerization of monomer in diluent by cross-linking agent. When diluent removed, it leaves tiny pores throughout polymerized spheres. Size and distribution of pores determined by amount and type of diluent and cross-linking agent.

  4. Magnetoresponsive Photonic Microspheres with Structural Color Gradient.

    Science.gov (United States)

    Lee, Seung Yeol; Choi, Jongkook; Jeong, Jong-Ryul; Shin, Jung H; Kim, Shin-Hyun

    2017-04-01

    Photonic Janus particles are created by alternately sputtering silica and titania on microspheres in order to obtain a structural color gradient. In addition, the microspheres are rendered magnetoresponsive. The Janus microspheres with optical and magnetic anisotropy enable on-demand control over orientation and structural color through manipulation of an external magnetic field, thereby being useful as active color pigments for reflection-mode displays. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Aceclofenac microspheres: Quality by design approach

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Rameshwar K.; Naik, Jitendra B., E-mail: jitunaik@gmail.com

    2014-03-01

    The purpose of this study was to prepare polymeric microspheres containing aceclofenac by single emulsion [oil-in-water (o/w)] solvent evaporation method. Two biocompatible polymers, ethylcellulose, and Eudragit® RS100 were used in combination. Seven processing factors were investigated by Plackett–Burman design (PBD) in order to enhance the encapsulation efficiency of the microspheres. A Plackett–Burman design was employed by using the Design-Expert® software (Version-8.0.7.1). The resultant microspheres were characterized for their size, morphology, encapsulation efficiency, and drug release. Imaging of particles was performed by field emission scanning electron microscopy. Interaction between the drug and polymers were investigated by Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffractometry (XRPD). Graphical and mathematical analyses of the design showed that Eudragit® RS100, and polyvinyl alcohol (PVA) were significant negative effect on the encapsulation efficiency and identified as the significant factor determining the encapsulation efficiency of the microspheres. The low magnitudes of error and the significant values of R{sup 2} in the present investigation prove the high prognostic ability of the design. The microspheres showed high encapsulation efficiency (70.15% to 83.82%). The microspheres were found to be discrete, oval with smooth surface. The FTIR analysis confirmed the compatibility of aceclofenac with the polymers. The XRPD revealed the dispersion of drug within microspheres formulation. Perfect prolonged drug release profile over 12 h was achieved by a combination of ethylcellulose, and Eudragit® RS100 polymers. In conclusion, polymeric microspheres containing aceclofenac can be successfully prepared using the technique of experimental design, and these results helped in finding the optimum formulation variables for encapsulation efficiency of microspheres. - Graphical abstract: The polymeric microspheres

  6. Granulomatous peritonitis caused by glove starch.

    OpenAIRE

    Michowitz, M.; Stavorovsky, M.; Ilie, B.

    1983-01-01

    Corn starch particles are used as a surgical glove lubricant. At present there is no better alternative for this lubricant. Implantation of corn starch particles into the peritoneal cavity can induce foreign body reactions, starch peritonitis and starch granulomata, and may cause adhesions and intestinal obstruction. Starch peritonitis should be treated conservatively.

  7. Comparative study on sustained release of human growth hormone from semi-crystalline poly(L-lactic acid) and amorphous poly(D,L-lactic-co-glycolic acid) microspheres: morphological effect on protein release.

    Science.gov (United States)

    Kim, Hong Kee; Park, Tae Gwan

    2004-07-23

    Recombinant human growth hormone (rhGH) was encapsulated by a double emulsion solvent evaporation method within two biodegradable microspheres having different polymer compositions. Semi-crystalline poly(L-lactic acid) (PLA) and amorphous poly(D,L-lactic-co-glycolic acid) (PLGA) were used for the encapsulation of hGH. Protein release profiles from the two microspheres were comparatively evaluated with respect to their morphological difference. Both of the microspheres similarly exhibited rugged surface and porous internal structures, but their inner pore wall morphologies were quite different. The slowly degrading PLA microspheres had many nano-scale reticulated pores on the wall, while the relatively fast degrading PLGA microspheres had a non-porous and smooth wall structure. From the PLA microspheres, hGH was released out in a sustained manner with an initial approximately 20% burst, followed by constant release, and almost 100% complete release after a 1-month period. In contrast, the PLGA microspheres showed a similar burst level of approximately 20%, followed by much slower release, but incomplete release of approximately 50% after the same period. The different hGH release profiles between PLA and PLGA microspheres were attributed to different morphological characters of the pore wall structure. The inter-connected nano-porous structure of PLA microspheres was likely to be formed due to the preferable crystallization of PLA during the solvent evaporation process.

  8. Sago Starch-Mixed Low-Density Polyethylene Biodegradable Polymer: Synthesis and Characterization

    Directory of Open Access Journals (Sweden)

    Md Enamul Hoque

    2013-01-01

    Full Text Available This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable polymer. Firstly, the effect of variation of starch content on mechanical property (elongation at break and Young’s modulus and biodegradability of the polymer was studied. The LDPE was combined with 10%, 30%, 50%, and 70% of sago for this study. Then how the cross-linking with trimethylolpropane triacrylate (TMPTA and electron beam (EB irradiation influence the mechanical and thermal properties of the polymer was investigated. In the 2nd study, to avoid overwhelming of data LDPE polymer was incorporated with only 50% of starch. The starch content had direct influence on mechanical property and biodegradability of the polymer. The elongation at break decreased with increase of starch content, while Young’s modulus and mass loss (i.e., degradation were found to increase with increase of starch content. Increase of cross-linker (TMPTA and EB doses also resulted in increased Young’s modulus of the polymer. However, both cross-linking and EB irradiation processes rendered lowering of polymer’s melting temperature. In conclusion, starch content and modification processes play significant roles in controlling mechanical, thermal, and degradation properties of the starch-mixed LDPE synthetic polymer, thus providing the opportunity to modulate the polymer properties for tailored applications.

  9. A metabolic pathway assembled by enzyme selection may support herbivory of leaf-cutter ants on plant starch.

    Science.gov (United States)

    Bacci, Maurício; Bueno, Odair Correa; Rodrigues, André; Pagnocca, Fernando Carlos; Somera, Alexandre Favarin; Silva, Aline

    2013-05-01

    Mutualistic associations shape the evolution in different organism groups. The association between the leaf-cutter ant Atta sexdens and the basidiomycete fungus Leucoagaricus gongylophorus has enabled them to degrade starch from plant material generating glucose, which is a major food source for both mutualists. Starch degradation is promoted by enzymes contained in the fecal fluid that ants deposit on the fungus culture in cut leaves inside the nests. To understand the dynamics of starch degradation in ant nests, we purified and characterized starch degrading enzymes from the ant fecal fluid and from laboratory cultures of L. gongylophorus and found that the ants intestine positively selects fungal α-amylase and a maltase likely produced by the ants, as a negative selection is imposed to fungal maltase and ant α-amylases. Selected enzymes are more resistant to catabolic repression by glucose and proposed to structure a metabolic pathway in which the fungal α-amylase initiates starch catalysis to generate byproducts which are sequentially degraded by the maltase to produce glucose. The pathway is responsible for effective degradation of starch and proposed to represent a major evolutionary innovation enabling efficient starch assimilation from plant material by leaf-cutters. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Radiolysis of starch

    International Nuclear Information System (INIS)

    Raffi, J.; Saint-Lebe, L.; Berger, G.

    1978-01-01

    In the first part of the paper the results of work on the identification and determination of the gamma ( 60 Co) radiolysis products of maize starch are brought together and, wherever possible, a balance drawn up by chemical class. The second part of the paper deals with the main parameters governing radiolysis: dose, irradiation temperature and atmosphere, water content and the conditions under which the irradiated starch is stored. The third part, devoted to the mechanisms believed to be involved, contains the following conclusions: (a) the formation of radiation-induced products with a carbon skeleton probably results from a breaking of the -C-O-C- chains with rearrangement of the radicals and/or a reaction involving the water and the oxygen - the oxygen has an activating effect which does not fundamentally modify the mechanism, whereas the effect of the water is more complex and varies according to the product; (b) the formation of hydrogen peroxide probably implies the addition of atmospheric oxygen to the radiation-induced hydrogen atoms in the water or to the organic radicals obtained by abstraction of a hydrogen from the starch. Lastly, the different methods envisaged for confirming or improving the mechanistic hypotheses are discussed. (author)

  11. Hydrothermally Synthesized Zinc Sulphide Microspheres for Solar Light-Driven Photocatalytic Properties

    Science.gov (United States)

    Waghadkar, Yogesh; Arbuj, Sudhir; Shinde, Manish; Ballal, Reshma; Rane, Sunit B.; Gosavi, Suresh; Fouad, H.; Chauhan, Ratna

    2018-02-01

    In this work, we reported the synthesis of zinc sulphide microspheres using the hydrothermal method. ZnS microspheres were synthesized using water, zinc acetate, thiourea and ammonia solution at 150°C for 6 h, 12 h, and 24 h. The as-synthesized ZnS powders were characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet-visible (UV-Vis) spectroscopy. XRD indicates the cubic (major phase) as well as hexagonal (minor phase) crystalline phase with enhanced crystallinity increased gradually with more reaction time. UV-Vis spectra show the absorption peaks in the UV-Vis region for all the samples. The Tauc's plot was used to calculate the band gap energy of ZnS samples, which are found to be 3.39 eV, 3.4 eV, and 3.42 eV for the samples synthesized at reaction times of 6 h, 12 h, and 24 h, respectively. FESEM images confirm the formation of microspheres as aggregates of spherical nanoparticles. The as-synthesized ZnS microspheres have been explored for solar light-induced photo-catalytic dye degradation of methylene blue (MB), and the results confirm that such microspheres exhibit effectual photocatalytic properties.

  12. Effects of Radiation on Mechanical Properties of Poly (butylene succinate) and Cassava Starch Blends

    International Nuclear Information System (INIS)

    Hemvichian, K.; Dechasasawat, K.; Kangsumrith, W.; Suwanmala, P.

    2014-01-01

    This research compared the effects of gamma and electron beam irradiation at different doses on the mechanical properties of polymer blends between poly(butylene succinate) (PBS) and cassava starch. Two types of starch were used to prepare thermoplastic starch (TPS), native cassava starch and hydrophobic starch. PBS/TPS blends were compounded at five different weight ratios using a twin-screw extruder. Mechanical properties and degradation were evaluated in comparison to unirradiated samples. Results indicated that the incorpora- tion of TPS prepared from native cassava starch decreased the mechanical properties of PBS/TPS blends, whereas the addition of TPS prepared from hydrophobic starch improved the mechanical properties of the blends. In addition, the maximum mechanical properties of PBS/TPS blends were achieved when samples were exposed to irradiation at 120 kGy. Using soil burial evaluation, the degradation rate of blends was found to increase with the addition of TPS. Therefore we have demonstrated in this study that the type of TPS and irradiation treatment can significantly alter the mechanical properties and degradation of PBS/TPS blends.

  13. Studies on gamma-irradiation of high amylose corn starch, 1

    International Nuclear Information System (INIS)

    Watanabe, Yukio; Ayano, Yuko; Obara, Tetsujiro.

    1976-01-01

    Amylomaize 7, amylomaize 5, normal corn, waxy corn and potato starches were irradiated with 60 Co-gamma rays at the dose levels from 2x10 4 to 100x10 4 rad to determine the changes in physicochemical properties by irradiation. Irradiated starches were characterized by determination of amylography, specific viscosity, blue value, pH, acidity, carbonyl content, reducing value and limit of β-amylolysis. Irradiated starches showed a decrease in viscosity and blue value, and an increase in reducing value with increasing dose levels. These results were seemed to indicate the degradation of starch molecule. A slight oxidation of starch was suggested by a decrease in pH and an increase in acidity and carbonyl content. Amylomaize 7 and amylomaize 5 starches were less sensitive than the other starches in terms of irradiation effects. The rheological properties determined by amylography and Ostwald viscometer changed at the lowest dose (5x10 4 rad) and the other properties changed above 20x10 4 rad. The limits of β-amylase hydrolysis of normal corn, waxy corn and potato starches increased slightly by irradiation (100x10 4 rad). On the other hand, β-amylolysis limits of amylomaize 7 and amylomaize 5 starches were lower about 5.5% and 2.5% respectively than that of nonirradiated samples. The decrease of β-amylolysis limit enlarged with increasing amylose content. (auth.)

  14. Functional properties of irradiated starch

    International Nuclear Information System (INIS)

    Laouini, Wissal

    2011-01-01

    Irradiation is an effective method capable of modifying the functional properties of starches. Its effect depends on the specific structural and molecular organization of starch granules from different botanical sources. In this study, we have studied the effect of gamma irradiation (3, 5, 10, 20, 35, 50 kGy) on the rheological properties of some varieties of starch (potato, cassava and wheat). First, we were interested in determining dry matter content; the results showed that the variation in dry matter compared to the control (native starch) is almost zero. So it does not depend on the dose of irradiation. Contrariwise, it differs from a botanical species to another. The viscometer has shown that these starches develop different behaviors during shearing. The native potato starch gave the highest viscosity followed by wheat and cassava which have almost similar viscosities. For all varieties, the viscosity of starch decreases dramatically with an increasing dose of irradiation. At high doses (35 and 50 kGy) the behavior of different starch is similar to that of a viscous pure liquid. The textural analysis via the back-extrusion test showed that increasing the dose of radiation causes a decrease in extrusion force and the energy spent of the different starch throughout the test. Indeed, the extrusion resistance decreases with increasing dose.

  15. Balancing mechanical strength with bioactivity in chitosan-calcium phosphate 3D microsphere scaffolds for bone tissue engineering: air- vs. freeze-drying processes.

    Science.gov (United States)

    Nguyen, D T; McCanless, J D; Mecwan, M M; Noblett, A P; Haggard, W O; Smith, R A; Bumgardner, J D

    2013-01-01

    The objective of this study was to evaluate the potential benefit of 3D composite scaffolds composed of chitosan and calcium phosphate for bone tissue engineering. Additionally, incorporation of mechanically weak lyophilized microspheres within those air-dried (AD) was considered for enhanced bioactivity. AD microsphere, alone, and air- and freeze-dried microsphere (FDAD) 3D scaffolds were evaluated in vitro using a 28-day osteogenic culture model with the Saos-2 cell line. Mechanical testing, quantitative microscopy, and lysozyme-driven enzymatic degradation of the scaffolds were also studied. FDAD scaffold showed a higher concentration (p mechanical strength was sacrificed through introduction of the less stiff, porous FD spheres.

  16. Microsphere fluoroimmunoassay for microorganisms: An update

    Energy Technology Data Exchange (ETDEWEB)

    Whitten, W.B.; Ramsey, J.M. [Oak Ridge National Lab., TN (United States); Bronk, B.V. [Edgewood Research, Development and Engineering Center, Aberdeen Proving Ground, MD (United States)

    1994-12-31

    Microspheres are used as labels in a fluorescence immunoassay for individual microorganisms. The diameter of a sphere that has reacted with microorganisms is determined from measurements of the optical resonance frequencies. The spheres have been coated with antibodies so that each microsphere diameter corresponds to a different species of microorganism. Further experiments on specificity and on optical resonance measurements are presented.

  17. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  18. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Hydroxyapatite (HAP) microspheres with peculiar spheres-in-sphere morphology were prepared by using oil-in-water emulsions and solvent evaporation technique. Ethylene vinyl acetate co-polymer (EVA) was used as the binder material. Preparation of HAP/EVA microspheres was followed by the thermal de-.

  19. Biodegradable poly (lactic acid) microspheres containing total ...

    Indian Academy of Sciences (India)

    The fabrication of biodegradable poly(lactic acid) (PLA) microspheres containing total alkaloids of Caulis sinomenii was investigated. The formation, diameter, morphology and properties of the microspheres were characterized using Fourier transform infrared spectroscopy (FT–IR), laser particle size analyser and scanning ...

  20. Microencapsulation and microspheres for food applications

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    This book provides an update on the latest developments, challenges, and opportunities in the highly expanding field of microencapsulation and microspheres for food applications, examining the various types of microspheres and microcapsules essential to those who need to develop stable and

  1. U3O8 microspheres sintering kinetics

    International Nuclear Information System (INIS)

    Godoy, A.L.E.

    1986-01-01

    U 3 O 8 microspheres sintering kinetics was determined using a hot-stage optical microscopy apparatus, able to reach temperature up to 1350 0 C in controlled atmospheres. The sintered material had its microstructure analysed by optical and electron microscopy. The microspheres were characterized initialy utilizing X-ray diffractometry and thermogravimetry. The equation which describes the microspheres shrinkage in function of the time was obtained using finite difference analysis X-ray diffractometry indicated hexagonal structure for the microspheres main starting material, ammonium diuranate thermogravimetric analysis showed reduction of this material to U 3 O 8 at 600 0 C. Ceramography results showed 5 hours sintered microspheres grain sizes G vary with the temperature. Sintered U 3 O 8 micrographs compared with published results for UO 2 , indicate similar homogeneity microstructural characteristics and suggest the processed micorspheres to be potentially useful as nuclear fuels. (Author) [pt

  2. Magnetic susceptibility characterisation of superparamagnetic microspheres

    Science.gov (United States)

    Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

    2018-04-01

    The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

  3. Plantain starch granules morphology, crystallinity, structure transition, and size evolution upon acid hydrolysis.

    Science.gov (United States)

    Hernández-Jaimes, C; Bello-Pérez, L A; Vernon-Carter, E J; Alvarez-Ramirez, J

    2013-06-05

    Plantain native starch was hydrolysed with sulphuric acid for twenty days. Hydrolysis kinetics was described by a logistic function, with a zero-order rate during the first seven days, followed by a slower kinetics dynamics at longer times. X-ray diffraction results revealed a that gradual increase in crystallinity occurred during the first seven days, followed by a decrease to values similar to those found in the native starch. Differential scanning calorimetry analysis suggested a sharp structure transition by the seventh day probably due to a molecular rearrangement of the starch blocklets and inhomogeneous erosion of the amorphous regions and semi crystalline lamellae. Scanning electron micrographs showed that starch granules morphology was continually degraded from an initial oval-like shape to irregular shapes due to aggregation effects. Granule size distribution broadened as hydrolysis time proceeded probably due to fragmentation and agglomeration phenomena of the hydrolysed starch granules. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Modification of mechanical and thermal property of chitosan-starch blend films

    Science.gov (United States)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M. E.; Khan, Ruhul A.; Dafader, N. C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-10-01

    Chitosan-starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan-starch films, glycerol and mustard oil of different composition were used. Chitosan-starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan-starch films. Water uptake of the films reduced significantly than the pure chitosan-starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively.

  5. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  6. Preparation and photocatalytic properties of core-shell nano-TiO2 @ α-Al2O3 microspheres.

    Science.gov (United States)

    Jing, Mao-Xiang; Han, Chong; Wang, Zhou; Shen, Xiang-Qian

    2014-09-01

    Core-shell nano-TiO2@a-Al2O3 microspheres of 5-20 μm were prepared by the heterogeneous precipitation method combined with the hydro-thermal and calcination process using α-Al2O3 microspheres as substrate. Their morphologies, microstructure and crystalline phase were characterized by SEM and XRD respectively. The photocatalytic activity was evaluated by degradation of methyl orange. The as-prepared 10 wt.% nano-TiO2@α -Al2O3 microspheres possess α core-shell structure with a monolayer of nano-TiO2 particles less than 30 nm on the surface of α-Al2O3 microspheres. Their photocatalytic properties are largely influenced by the calcination temperature and the sample calcined at 800 degrees C for 2 h has the best photocatalytic activity. This high photocatalytic activity can be attributed to the synergetic effects of the unique structure of nano-TiO2 @α-Al2O3 microspheres, quantum size effect, composition of crystalline phase and crystallinity of nano-TiO2. These nano-TiO2@α-Al2O3 microspheres may be conveniently separable and useful in practical treatment of organic waste waters due to the large particle size and high photocatalytic properties.

  7. Optimized Bone Regeneration in Calvarial Bone Defect Based on Biodegradation-Tailoring Dual-shell Biphasic Bioactive Ceramic Microspheres.

    Science.gov (United States)

    Xu, Antian; Zhuang, Chen; Xu, Shuxin; He, Fuming; Xie, Lijun; Yang, Xianyan; Gou, Zhongru

    2018-02-21

    Bioceramic particulates capable of filling bone defects have gained considerable interest over the last decade. Herein, dual-shell bioceramic microspheres (CaP@CaSi@CaP, CaSi@CaP@CaSi) with adjustable beta-tricalcium phosphate (CaP) and beta-calcium silicate (CaSi) distribution were fabricated using a co-concentric capillary system enabling bone repair via a tailorable biodegradation process. The in vitro results showed the optimal concentration (1/16 of 200 mg/ml) of extracts of dual-shell microspheres could promote bone marrow mesenchymal cell (BMSC) proliferation and enhance the level of ALP activity and Alizarin Red staining. The in vivo bone repair and microsphere biodegradation in calvarial bone defects were compared using micro-computed tomography and histological evaluations. The results indicated the pure CaP microspheres were minimally resorbed at 18 weeks post-operatively and new bone tissue was limited; however, the dual-shell microspheres were appreciably biodegraded with time in accordance with the priority from CaSi to CaP in specific layers. The CaSi@CaP@CaSi group showed a significantly higher ability to promote bone regeneration than the CaP@CaSi@CaP group. This study indicates that the biphasic microspheres with adjustable composition distribution are promising for tailoring material degradation and bone regeneration rate, and such versatile design strategy is thought to fabricate various advanced biomaterials with tailorable biological performances for bone reconstruction.

  8. One-step growth of nanosheet-assembled BiOCl/BiOBr microspheres for highly efficient visible photocatalytic performance

    Science.gov (United States)

    Zhang, Jinfeng; Lv, Jiali; Dai, Kai; Liang, Changhao; Liu, Qi

    2018-02-01

    In this work, we have developed a simple synthetic approach of nanosheet-assembled BiOCl/BiOBr microspheres by an ethylene glycol (EG)-assisted hydrothermal method. The crystalline form, morphology, chemical composition, optical performance and surface area of BiOCl/BiOBr microspheres were identified using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy spectra (EDX), UV-vis diffuse reflectance spectroscopy (DRS) analysis, high resolution X-ray photoelectron spectra (XPS) and N2 adsorption-desorption isotherms. BiOCl/BiOBr microspheres were nanosheet-assembled particles, which possessed visible light absorption under LED light irridation. Additionally, the methylene blue (MB) photodegradation performance of different BiOCl/BiOBr microspheres irradiated under 410 nm LED light arrays were investigated, the results exhibited that as-prepared BiOCl/BiOBr products showed higher catalytic effiency than pure BiOCl or BiOBr. By optimizing the composition ration of the BiOCl and BiOBr, up to 93% degradation rate can be obtained in the 40%BiOCl/BiOBr microspheres. Finally, the photocatalytic mechanism of BiOCl/BiOBr microspheres had been proposed.

  9. Downregulation of chloroplast-targeted beta-amylase leads to a starch-excess phenotype in leaves

    DEFF Research Database (Denmark)

    Scheidig, A.; Fröhlich, A.; Schulze, S.

    2002-01-01

    A functional screen in Escherichia coli was established to identify potato genes coding for proteins involved in transitory starch degradation. One clone isolated had a sequence very similar to a recently described chloroplast-targeted 5-amylase of Arabidopsis. Expression of the gene in E. coli s...... that the antisense plants degraded only 8-30% of their total starch, in comparison with 50% in the wild type, over the dark period. This is the first time that a physiological role for a beta-amylase in plants has been demonstrated....... degradation, transgenic potato plants were generated where its activity was reduced using antisense techniques. Analysis of plants reduced in the presence of this beta-amylase isoform showed that their leaves had a starch-excess phenotype, indicating a defect in starch degradation. In addition, it was shown...

  10. Physicochemical properties of maca starch.

    Science.gov (United States)

    Zhang, Ling; Li, Guantian; Wang, Sunan; Yao, Weirong; Zhu, Fan

    2017-03-01

    Maca (Lepidium meyenii Walpers) is gaining research attention due to its unique bioactive properties. Starch is a major component of maca roots, thus representing a novel starch source. In this study, the properties of three maca starches (yellow, purple and black) were compared with commercially maize, cassava, and potato starches. The starch granule sizes ranged from 9.0 to 9.6μm, and the granules were irregularly oval. All the maca starches presented B-type X-ray diffraction patterns, with the relative degree of crystallinity ranging from 22.2 to 24.3%. The apparent amylose contents ranged from 21.0 to 21.3%. The onset gelatinization temperatures ranged from 47.1 to 47.5°C as indicated by differential scanning calorimetry. Significant differences were observed in the pasting properties and textural parameters among all of the studied starches. These characteristics suggest the utility of native maca starch in products subjected to low temperatures during food processing and other industrial applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effect of Nylon Bag and Protozoa on In Vitro Corn Starch Disappearance

    NARCIS (Netherlands)

    Zwieten, van J.T.; Vuuren, van A.M.; Dijkstra, J.

    2008-01-01

    An in vitro experiment was carried out to study whether the presence of protozoa in nylon bags can explain the underestimation of the in situ degradation of slowly degradable starch. Corn of a high (flint) and a low (dent) vitreousness variety was ground over a 3-mm screen, weighed in nylon bags

  12. Understanding shape and morphology of unusual tubular starch nanocrystals.

    Science.gov (United States)

    Gong, Bei; Liu, Wenxia; Tan, Hua; Yu, Dehai; Song, Zhaoping; Lucia, Lucian A

    2016-10-20

    Starch nanocrystals (SNC) are aptly described as the insoluble degradation byproducts of starch granules that purportedly display morphologies that are platelet-like, round, square, and oval-like. In this work, we reported the preparation of SNC with unprecedented tubular structures through sulfuric acid hydrolysis of normal maize starch, subsequent exposure to ammonia and relaxation at 4°C. High-resolution transmission electron microscopy observation clearly proved that the SNCs possess tubular nanostructures with polygonal cross-section. After further reviewing the transformations of SNC by acid hydrolysis, ammonia treatment, and curing time at 4°C, a mechanism for T-SNC formation is suggested. It is conjectured that T-SNC gradually self-assembles by combination of smaller platelet-like/square nanocrystals likely loosely aggregated by starch molecular chains from residual amorphous regions. This work paves the way for the pursuit of new approaches for the preparation of starch-based nanomaterials possessing unique morphologies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Thermal Behavior of Tacca leontopetaloides Starch-Based Biopolymer

    Directory of Open Access Journals (Sweden)

    Nurul Shuhada Mohd Makhtar

    2013-01-01

    Full Text Available Starch is used whenever there is a need for natural elastic properties combined with low cost of production. However, the hydrophilic properties in structural starch will decrease the thermal performance of formulated starch polymer. Therefore, the effect of glycerol, palm olein, and crude palm oil (CPO, as plasticizers, on the thermal behavior of Tacca leontopetaloides starch incorporated with natural rubber in biopolymer production was investigated in this paper. Four different formulations were performed and represented by TPE1, TPE2, TPE3, and TPE4. The compositions were produced by using two-roll mill compounding. The sheets obtained were cut into small sizes prior to thermal testing. The addition of glycerol shows higher enthalpy of diffusion in which made the material easily can be degraded, leaving to an amount of 6.6% of residue. Blending of CPO with starch (TPE3 had a higher thermal resistance towards high temperature up to 310°C and the thermal behavior of TPE2 only gave a moderate performance compared with other TPEs.

  14. Solid evacuated microspheres of hydrogen

    Science.gov (United States)

    Turnbull, Robert J.; Foster, Christopher A.; Hendricks, Charles D.

    1982-01-01

    A method is provided for producing solid, evacuated microspheres comprised of hydrogen. The spheres are produced by forming a jet of liquid hydrogen and exciting mechanical waves on the jet of appropriate frequency so that the jet breaks up into drops with a bubble formed in each drop by cavitation. The drops are exposed to a pressure less than the vapor pressure of the liquid hydrogen so that the bubble which is formed within each drop expands. The drops which contain bubbles are exposed to an environment having a pressure just below the triple point of liquid hydrogen and they thereby freeze giving solid, evacuated spheres of hydrogen.

  15. Nuclear fuel microsphere gamma analyzer

    International Nuclear Information System (INIS)

    Valentine, K.H.; Long, E.L. Jr.; Willey, M.G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties. 4 claims, 3 figures

  16. Compatibility, Morphology, Mechanical Properties and Biodegradability of Poly(styrene-ethylene-propylenestyrene/ Modified Thermoplastic Starch Blends

    Directory of Open Access Journals (Sweden)

    Saaid Rahimi Bandarabadi

    2016-09-01

    Full Text Available The effect of modified starch on the properties of poly(styrene-ethylenepropylene- styrene tri-block copolymer was studied. Chemical treatment of starch with maleic anhydride was accomplished in an internal mixer in the presence of glycerol. The reaction was confirmed using Fourier infrared spectroscopy (FTIR and titration. The blend samples containing 10, 20, 30 and 50 wt% were obtained by melt blending and their mechanical, morphological and dynamic-mechanical properties were studied. Scanning electron microscopy (SEM images displayed droplet-matrix morphology and with increases in modified starch up to 50 wt% some partial co-continuous morphology was also observed. With increase of modified starch in the compound, the size of dispersed phase increased. DMTA results revealed that the partial compatibility was obtained because of slight difference between glass transition temperatures of two phases in the presence of modified starch. The peak of modified starch shifted to higher values and the differences between the two peaks decreased, indicating partial compatibility. Mechanical properties including tensile, elongation-at-break and modulus were also determined and the results showed that the mechanical properties of the sample were higher than those of neat TPS because of the higher compatibility. Tensile strength was decreased with increase in modified starch content due to the absence of strong interfacial adhesion. Moduli of the samples were increased with increase in modified starch content due to higher stiffness of starch. Biodegradability of the samples was evaluated by weight loss percentage using compost test. A rapid degradation was observed in the first 45 days and with increase of the modified starch content the degree of degradation was increased.

  17. Improved starch recovery from potatoes by enzymes and reduced water holding of the residual fibres.

    Science.gov (United States)

    Ramasamy, Urmila R; Lips, Steef; Bakker, Rob; Gruppen, Harry; Kabel, Mirjam A

    2014-11-26

    During the industrial extraction of starch from potatoes (Seresta), some starch remains within undisrupted potato cells in the fibrous side-stream. The aim of this study was to investigate if enzymatic degradation of cell wall polysaccharides (CWPs) can enhance starch recovery and lower the water holding capacity (WHC) of the "fibre" fraction. The use of a pectinase-rich preparation recovered 58% of the starch present in the "fibre" fraction. Also, the "fibre" fraction retained only 40% of the water present in the non-enzyme treated "fibre". This was caused by the degradation of pectins, in particular arabinogalactan side chains calculated as the sum of galactosyl and arabinosyl residues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Starches, Sugars and Obesity

    Directory of Open Access Journals (Sweden)

    Erik E. J. G. Aller

    2011-03-01

    Full Text Available The rising prevalence of obesity, not only in adults but also in children and adolescents, is one of the most important public health problems in developed and developing countries. As one possible way to tackle obesity, a great interest has been stimulated in understanding the relationship between different types of dietary carbohydrate and appetite regulation, body weight and body composition. The present article reviews the conclusions from recent reviews and meta-analyses on the effects of different starches and sugars on body weight management and metabolic disturbances, and provides an update of the most recent studies on this topic. From the literature reviewed in this paper, potential beneficial effects of intake of starchy foods, especially those containing slowly-digestible and resistant starches, and potential detrimental effects of high intakes of fructose become apparent. This supports the intake of whole grains, legumes and vegetables, which contain more appropriate sources of carbohydrates associated with reduced risk of cardiovascular and other chronic diseases, rather than foods rich in sugars, especially in the form of sugar-sweetened beverages.

  19. Starches, sugars and obesity.

    Science.gov (United States)

    Aller, Erik E J G; Abete, Itziar; Astrup, Arne; Martinez, J Alfredo; van Baak, Marleen A

    2011-03-01

    The rising prevalence of obesity, not only in adults but also in children and adolescents, is one of the most important public health problems in developed and developing countries. As one possible way to tackle obesity, a great interest has been stimulated in understanding the relationship between different types of dietary carbohydrate and appetite regulation, body weight and body composition. The present article reviews the conclusions from recent reviews and meta-analyses on the effects of different starches and sugars on body weight management and metabolic disturbances, and provides an update of the most recent studies on this topic. From the literature reviewed in this paper, potential beneficial effects of intake of starchy foods, especially those containing slowly-digestible and resistant starches, and potential detrimental effects of high intakes of fructose become apparent. This supports the intake of whole grains, legumes and vegetables, which contain more appropriate sources of carbohydrates associated with reduced risk of cardiovascular and other chronic diseases, rather than foods rich in sugars, especially in the form of sugar-sweetened beverages.

  20. Production of RS4 from rice starch and its utilization as an encapsulating agent for targeted delivery of probiotics.

    Science.gov (United States)

    Ashwar, Bilal Ahmad; Gani, Asir; Gani, Adil; Shah, Asima; Masoodi, Farooq Ahmad

    2018-01-15

    The research reported in this article is based on the hypothesis that crosslinking of starch can make it a potential wall material for targeted delivery of probiotics by altering its digestion. Three probiotic strains namely Lactobacillus casei, Lactobacillus brevis and Lactobacillus plantarum were microencapsulated with resistant starch. Encapsulation yield (%) of resistant starch microspheres was in the range of 43.01-48.46. The average diameter of resistant starch microparticles was in the range of 45.53-49.29μm. Fourier transform infrared (FT-IR) spectroscopy of microcapsules showed peaks in the region of 900-1300cm -1 and 2918-2925cm -1 which corresponds to the presence of bacteria. Differential Scanning Calorimeter (DSC) showed better thermal stability of resistant starch microcapsules. Microencapsulated probiotics survived well in simulated gastrointestinal conditions and adverse heat conditions. The viability of the microcapsulated lactobacilli also remained high (>7 log cfu g -1 ) for 2months at 4°C. The results revealed that resistant starch is the potential new delivery carrier for oral administration of probiotics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effect of γ-irradiation on pasting and emulsification properties of octenyl succinylated rice starches.

    Science.gov (United States)

    Han, Jung-Ah; Lim, Seung-Taik

    2012-11-06

    Octenylsuccinylated (OS) starches from waxy rice or high-amylose rice (28.1% amylose) (DS 0.023 and 0.025, respectively) were gamma-irradiated at 10, 30, or 50 kGy and their pasting and thermal properties, crystallinity, and emulsification property were examined. When the OS starches were irradiated, the degrees of substitution gradually decreased as irradiation dose increased. A significant decrease in pasting viscosity was observed with an increase in irradiation dose, indicating the presence of chain degradation induced by the radiation. The melting temperature and enthalpy determined by differential scanning calorimetry increased slightly by irradiating at 10 or 30 kGy. Little change in crystallinity was observed in the X-ray diffraction analysis for the OS high-amylose rice starch regardless of irradiation doses, whereas a decrease in crystallinity was observed with the OS waxy starch irradiated at 50 kGy. Chain degradation induced by irradiation occurred mainly in the amorphous regions, but some loss of crystallinity occurred when the irradiation was excessive. The OS starches showed greater emulsion capacity and stability than the native counterparts due to their amphipathic nature. The irradiation further improved the emulsification properties of OS starches. The irradiation at 10 kGy was optimal, and treating at higher doses decreased the emulsion capacity and stability of the OS starches. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Aceclofenac microspheres: quality by design approach.

    Science.gov (United States)

    Deshmukh, Rameshwar K; Naik, Jitendra B

    2014-03-01

    The purpose of this study was to prepare polymeric microspheres containing aceclofenac by single emulsion [oil-in-water (o/w)] solvent evaporation method. Two biocompatible polymers, ethylcellulose, and Eudragit® RS100 were used in combination. Seven processing factors were investigated by Plackett-Burman design (PBD) in order to enhance the encapsulation efficiency of the microspheres. A Plackett-Burman design was employed by using the Design-Expert® software (Version-8.0.7.1). The resultant microspheres were characterized for their size, morphology, encapsulation efficiency, and drug release. Imaging of particles was performed by field emission scanning electron microscopy. Interaction between the drug and polymers were investigated by Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffractometry (XRPD). Graphical and mathematical analyses of the design showed that Eudragit® RS100, and polyvinyl alcohol (PVA) were significant negative effect on the encapsulation efficiency and identified as the significant factor determining the encapsulation efficiency of the microspheres. The low magnitudes of error and the significant values of R(2) in the present investigation prove the high prognostic ability of the design. The microspheres showed high encapsulation efficiency (70.15% to 83.82%). The microspheres were found to be discrete, oval with smooth surface. The FTIR analysis confirmed the compatibility of aceclofenac with the polymers. The XRPD revealed the dispersion of drug within microspheres formulation. Perfect prolonged drug release profile over 12h was achieved by a combination of ethylcellulose, and Eudragit® RS100 polymers. In conclusion, polymeric microspheres containing aceclofenac can be successfully prepared using the technique of experimental design, and these results helped in finding the optimum formulation variables for encapsulation efficiency of microspheres. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Biodegradation of polystyrene-graft-starch copolymers in three different types of soil.

    Science.gov (United States)

    Nikolic, Vladimir; Velickovic, Sava; Popovic, Aleksandar

    2014-01-01

    Materials based on polystyrene and starch copolymers are used in food packaging, water pollution treatment, and textile industry, and their biodegradability is a desired characteristic. In order to examine the degradation patterns of modified, biodegradable derivates of polystyrene, which may keep its excellent technical features but be more environmentally friendly at the same time, polystyrene-graft-starch biomaterials obtained by emulsion polymerization in the presence of new type of initiator/activator pair (potassium persulfate/different amines) were subjected to 6-month biodegradation by burial method in three different types of commercially available soils: soil rich in humus and soil for cactus and orchid growing. Biodegradation was monitored by mass decrease, and the highest degradation rate was achieved in soil for cactus growing (81.30%). Statistical analysis proved that microorganisms in different soil samples have different ability of biodegradation, and there is a significant negative correlation between the share of polystyrene in copolymer and degree of biodegradation. Grafting of polystyrene on starch on one hand prevents complete degradation of starch that is present (with maximal percentage of degraded starch ranging from 55 to 93%), while on the other hand there is an upper limit of share of polystyrene in the copolymer (ranging from 37 to 77%) that is preventing biodegradation of degradable part of copolymers.

  4. Study of the properties and biodegradability of polyester/starch blends submitted to microbial attack

    International Nuclear Information System (INIS)

    Vinhas, Gloria M.; Almeida, Yeda M.B. de; Lima, Maria Alice Gomes de Andrade; Santos, Livia Almeida

    2007-01-01

    This work deals with the biodegradation of blends of poly(beta-hydroxybutyrate)/starch and poly(beta-hydroxybutyrate-cohydroxyvalerate)/ starch. The blends were obtained by evaporation of the solvent in the mixture of the polymers in chloroform. Tests were carried out in presence of micro-organisms which acted as biodegradation agents. The blends were consumed as carbon substrate and the production of CO 2 was evaluated in the process. In addition, the polyesters' mechanical properties were reduced by the incorporation of starch in its structure. ( 1 H) NMR and infrared spectroscopy detected some characteristic polyester degradation groups in the polyesters' chemical structure, thus confirming the alteration suffered by it. (author)

  5. Substituent distribution within cross-linked and hydroxypropylated sweet potato starch and potato starch

    NARCIS (Netherlands)

    Zhao, J.; Schols, H.A.; Chen Zenghong,; Jin Zhengyu,; Buwalda, P.L.; Gruppen, H.

    2012-01-01

    Revealing the substituents distribution within starch can help to understand the changes of starch properties after modification. The distribution of substituents over cross-linked and hydroxypropylated sweet potato starch was investigated and compared with modified potato starch. The starches were

  6. Progress in Preparation of Monodisperse Polymer Microspheres

    Science.gov (United States)

    Zhang, Hongyan

    2017-12-01

    The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

  7. VISCOSITY OF CONCENTRATED POTATO-STARCH PASTES

    NARCIS (Netherlands)

    LAMMERS, G; BEENACKERS, AACM

    1994-01-01

    A new viscosity equation for the description of the viscosity of concentrated aqueous starch pastes is proposed: eta(app) = Ke([Bmstarch+(C/T)-DW+(n-1)ln gamma]) with: m(starch) = mass fraction starch in paste, T = temperature, W = amount of work performed on the starch, n = power-law index, K =

  8. In-vitro starch hydrolysis of chitosan incorporating whey protein and wheat starch composite gels

    Directory of Open Access Journals (Sweden)

    Natasha Yang

    2017-10-01

    Full Text Available The study examined the influence of chitosan, incorporated into whey protein and wheat starch thermo gels, on the in-vitro hydrolysis of the polysaccharide. Gels were subjected to the following external conditions containing α-amylase at constant incubation temperature of 37 °C: In the first procedure, they were immersed in phosphate buffer (0.05 M and maintained at pH 6.9 throughout the entire digestion. In the second instance, they were introduced into a salt solution, with pH and total volume adjusted at times in sync with the human gastrointestinal tract. Results indicate that low and medium molecular weight chitosan, in combination with whey protein, were effective at enhancing the protective barrier against starch degradation. Less maltose was liberated from gels containing medium molecular weight chitosan, as opposed to the low molecular weight counterpart, and results compare favorably with the outcome of the in-vitro digestion of binary whey protein and wheat starch composites. Keywords: Food science

  9. β-Cyclodextrin Production by Cyclodextrin Glucanotransferase from an Alkaliphile Microbacterium terrae KNR 9 Using Different Starch Substrates

    Directory of Open Access Journals (Sweden)

    Kiransinh N. Rajput

    2016-01-01

    Full Text Available Cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19 is an important member of α-amylase family which can degrade the starch and produce cyclodextrins (CDs as a result of intramolecular transglycosylation (cyclization. β-Cyclodextrin production was carried out using the purified CGTase enzyme from an alkaliphile Microbacterium terrae KNR 9 with different starches in raw as well as gelatinized form. Cyclodextrin production was confirmed using thin layer chromatography. Six different starch substrates, namely, soluble starch, potato starch, sago starch, corn starch, corn flour, and rice flour, were tested for CD production. Raw potato starch granules were found to be the best substrate giving 13.46 gm/L of cyclodextrins after 1 h of incubation at 60°C. Raw sago starch gave 12.96 gm/L of cyclodextrins as the second best substrate. To achieve the maximum cyclodextrin production, statistical optimization using Central Composite Design (CCD was carried out with three parameters, namely, potato starch concentration, CGTase enzyme concentration, and incubation temperature. Cyclodextrin production of 28.22 (gm/L was achieved with the optimized parameters suggested by the model which are CGTase 4.8 U/L, starch 150 gm/L, and temperature 55.6°C. The suggested optimized conditions showed about 15% increase in β-cyclodextrin production (28.22 gm/L at 55.6°C as compared to 24.48 gm/L at 60°C. The degradation of raw potato starch granules by purified CGTase was also confirmed by microscopic observations.

  10. Sago starch and its utilisation.

    Science.gov (United States)

    Abd-Aziz, Suraini

    2002-01-01

    The importance and development of industrial biotechnology processing has led to the utilisation of microbial enzymes in various applications. One of the important enzymes is amylase, which hydrolyses starch to glucose. In Malaysia, the use of sago starch has been increasing, and it is presently being used for the production of glucose. Sago starch represents an alternative cheap carbon source for fermentation processes that is attractive out of both economic and geographical considerations. Production of fermentable sugars from the hydrolysis of starches is normally carried out by an enzymatic processes that involves two reaction steps, liquefaction and saccharification, each of which has different temperature and pH optima with respect to the maximum reaction rate. This method of starch hydrolysis requires the use of an expensive temperature control system and a complex mixing device. Our laboratory has investigated the possibility of using amylolytic enzyme-producing microorganisms in the continuous single-step biological hydrolysis of sago flour for the production of a generic fermentation medium. The ability of a novel DNA-recombinated yeast, Saccharomyces cerevisiae strain YKU 107 (expressing alpha-amylase production) to hydrolyse gelatinised sago starch production has been studied with the aim of further utilizing sago starch to obtain value-added products.

  11. Sixth taste – starch taste?

    Directory of Open Access Journals (Sweden)

    Zygmunt Zdrojewicz

    2017-06-01

    Full Text Available Scientists from Oregon State University, USA, came up with the newest theory of the sixth taste – starch taste that might soon join the basic five tastes. This argument is supported by studies done on both animals and humans, the results of which seem to indicate the existence of separate receptors for starch taste, others than for sweet taste. Starch is a glucose homopolymer that forms an α-glucoside chain called glucosan or glucan. This polysaccharide constitutes the most important source of carbohydrates in food. It can be found in groats, potatoes, legumes, grains, manioc and corn. Apart from its presence in food, starch is also used in textile, pharmaceutical, cosmetic and stationery industries as well as in glue production. This polysaccharide is made of an unbranched helical structure – amylose (15–20%, and a structure that forms branched chains – amylopectin (80–85%. The starch structure, degree of its crystallisation or hydration as well as its availability determine the speed of food-contained starch hydrolysis by amylase. So far, starch has been considered tasteless, but the newest report shows that for people of different origins it is associated with various aliments specific for each culture. Apart from a number of scientific experiments using sweet taste inhibitors, the existence of the sixth taste is also confirmed by molecular studies. However, in order to officially include starch taste to the basic human tastes, it must fulfil certain criteria. The aim of the study is to present contemporary views on starch.

  12. Porous nano-HA/collagen/PLLA scaffold containing chitosan microspheres for controlled delivery of synthetic peptide derived from BMP-2.

    Science.gov (United States)

    Niu, Xufeng; Feng, Qingling; Wang, Mingbo; Guo, Xiaodong; Zheng, Qixin

    2009-03-04

    It is advantageous to incorporate controlled growth factor delivery into tissue engineering strategies. The purpose of the present study was to develop a novel tissue engineering scaffold with the capability of controlled releasing BMP-2-derived synthetic peptide. Porous nano-hydroxyapatite/collagen/poly(L-lactic acid)/chitosan microspheres (nHAC/PLLA/CMs) composite scaffolds containing different quantities of chitosan microspheres (CMs) were prepared by a thermally induced phase separation method. Dioxane was used as the solvent for PLLA. Introduction of less than 30% of CMs (on PLLA weight basis) did not remarkably affect the morphology and porosity of the nHAC/PLLA/CMs scaffolds. However, as the microspheres contents increased to 50%, the porosity of the composite decreased rapidly. The compressive modulus of the composite scaffolds increased from 15.4 to 25.5 MPa, while the compressive strength increased from 1.42 to 1.63 MPa as the microspheres contents increased from 0% to 50%. The hydrolytic degradation and synthetic peptide release kinetics in vitro were investigated by incubation in phosphate buffered saline solution (pH 7.4). The results indicated that the degradation rate of the scaffolds was increased with the enhancement of CMs dosage. The synthetic peptide was released in a temporally controlled manner, depending on the degradation of both incorporated chitosan microspheres and PLLA matrix. In vitro bioactivity assay revealed that the encapsulated synthetic peptide was biologically active as evidenced by stimulation of rabbit marrow mesenchymal stem cells (MSCs) alkaline phosphatase (ALP) activity. The successful microspheres-scaffold system offers a new delivery method of growth factors and a novel scaffold design for bone regeneration.

  13. The effects of different amounts of drug microspheres on the vivo and vitro performance of the PLGA/β-TCP scaffold.

    Science.gov (United States)

    Lin, Liulan; Wang, Tianjiang; Zhou, Qi; Qian, Niandong

    2017-01-01

    OIC-A006 (BMPs osteogenesis compounds), can stimulate bone marrow mesenchymal stem cells ALP, OPN, OC, Cbfal expression. To stimulate new bone formation in the body. We postulate different amounts of drug microspheres on the PLGA/β-CPT scaffold can produce the effects on performance and sustained release characteristics. In this paper, through adding different amount of carrier drug microsphere, three concentrations scaffolds which are 12.5, 18.75 and 25 μmol/L are prepared by adding different amounts of drug-loaded microspheres. Hereafter called OICM/CPT-200, OICM/CPT-300, OICM/CPT-400. We implant them in rat femur diameter 3 mm depth of 3 mm hole for eight weeks. The degradation, microsphere, delivery properties, with X-ray, micro-CT and histology are tested. Results show that the contain carrier drug microsphere scaffolds become radiopaque, and the gaps between the scaffold and radial cut ends are often invisible. This preliminary study reveals that different carrier drug microsphere has a corresponding effect the performance of stent body, OICM/CPT - 200 scaffolds induction effect is best. Illustrates that the low concentration load OIC-A006 microspheres can promote bone healing, and high concentration of OIC-A006 micro ball is played a inhibitory effect on bone healing process.

  14. Chemical Modifications of Starch: Microwave Effect

    OpenAIRE

    Lewicka, Kamila; Siemion, Przemysław; Kurcok, Piotr

    2015-01-01

    This paper presents basic methods of starch chemical modification, the effect of microwave radiation on the modification process, and the physicochemical properties of starch. It has been shown that the modifications contribute to improvement of the material performance and likewise to significant improvement of its mechanical properties. As a result, more and more extensive use of starch is possible in various industries. In addition, methods of oxidized starch and starch esters preparation ...

  15. Properties of Cakes of Different Starch Content

    OpenAIRE

    Ikawa, Yoshiko; Shiratuti, Hiroko

    1995-01-01

    Effects of five levels of substitution (0, 30, 50, 70, 100%) of wheat starch or corn starch for wheat flour on the properties of the sponge cakes and batters were investigated. The results were as follows: 1) Increase in starch ratio caused the decrease of batter viscosity and the increase of cake layer expansion during baking. While, replacement to corn starch induced greater shrinkage after maximum expansion according to increase of starch ratio, and consequently, there were no differen...

  16. Construct Scaffold-like delivery system with poly (lactic-co-glycolic) microspheres on micro-arc oxidation titanium

    Science.gov (United States)

    Wang, Lin; Zheng, Huade; Du, Chang; Shi, Zhifeng; Ren, Li; Wang, Yingjun

    2013-02-01

    In this paper, we present the first report about constructing a scaffold-like delivery system with poly (lactic-co-glycolic) (PLGA) microspheres on micro-arc oxidation titanium (MAO-Ti). The results show that this system could be stable on the porous MAO-Ti surface up for 6 weeks. Not only the system could control the release of model protein BSA, but also the MAO film could regulate the pH value of the solution which would decrease by the degradation of PLGA microspheres. In addition, compared to MAO-Ti, this system loaded with BSA could improve the proliferation of HBMSCs after 3 or 7 days culture.

  17. Preparation of potato starch microfibers obtained by electro wet spinning

    Science.gov (United States)

    Cárdenas, W.; Gómez-Pachon, E. Y.; Muñoz, E.; Vera-Graziano, R.

    2016-07-01

    Starch is one of the most abundant biopolymer in nature. It has been primarily used as a thickener in the food industry. Starch is found in greater amounts in the potato tubers, which is one of the largest food productions in the region of Boyacá-Colombia. Thus, potatoes are a viable source of starch. The main objective of this study is the preparation and characterization of native starch's microfiber by electro wet-spinning technique. The parameters that were changed for each treatment were as follows: the amount of potential applied to the solution, the distance between the needle and the collector and the rate of injection of the solution in order to determine the physical and chemical properties of the membranes, conformed by potatoes starch microfiber. Diverse instrumental analysis techniques were applied. They were: Scanning Electron Microscopy (SEM) to determine the morphologies and diameters of microfibers, Fourier Transform Infrared Spectroscopy (FTIR) to determine the chemical changes, Thermogravimetric Analysis (TGA) and Differential Calorimetry Scanning (DSC) to obtain the thermal transitions and the temperatures of useful. The microfibers were analysed in order to determine their structural properties and thus define the range of application. In conclusion, potatoes starch microfibers were obtained with average diameters of 15, 17, 23 and 25 micrometres, besides the fibers presented a degradation temperature of 304 °C, indicating that fibers are available with diameters of small scale, with good thermal properties. This study will enable the implementation of the microfibers to obtain bio packaging for food products and other applications.

  18. Prebiotic properties of potato starch dextrins

    Directory of Open Access Journals (Sweden)

    Renata Barczyńska

    2015-09-01

    Full Text Available The objective of the present study was to compare the prebiotic properties of starch dextrins, that is, resistant dextrins obtained from potato starch in the process of simultaneous thermolysis and chemical modification, which were selected based on previous research. Both prepared dextrins met the definition criterion of dietary fiber and also the basic prebiotic criterion – they were not degraded by the digestive enzymes of the initial sections of the gastrointestinal tract. The growth of probiotic lactobacilli and bifidobacteria, as well as Escherichia coli, Enterococcus, Bacteroides, and Clostridium strains isolated from feces of healthy people, showed that both studied dextrins were utilized as a source of assimilable carbon and energy by the strains. Furthermore, better growth (higher numbers of cells counts of probiotic bacteria than those of fecal isolates indicated that the studied resistant dextrins showed a selective effect. Both dextrins might be considered as substances with prebiotic properties due to their chemical and physical properties and selectivity towards the studied probiotic bacterial strains.

  19. Hierarchical synthesis of corrugated photocatalytic TiO{sub 2} microsphere architectures on natural pollen surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, Deniz Altunoz; Ozensoy, Emrah, E-mail: ozensoy@fen.bilkent.edu.tr

    2017-05-01

    Highlights: • Biotemplate-based photocatalytic material was synthesized in the form of corrugated TiO{sub 2} microspheres. • Characterization of photocatalysts as a function of temperature. • Photocatalytic activities studied in the gas and solution phases. - Abstract: Biomaterials are challenging, yet vastly promising templates for engineering unusual inorganic materials with unprecedented surface and structural properties. In the current work, a novel biotemplate-based photocatalytic material was synthesized in the form of corrugated TiO{sub 2} microspheres by utilizing a sol-gel methodology where Ambrosia trifida (Ab, Giant ragweed) pollen was exploited as the initial biological support surface. Hierarchically synthesized TiO{sub 2} microspheres were structurally characterized in detail via SEM-EDX, Raman spectroscopy, XRD and BET techniques in order to shed light on the surface chemistry, crystal structure, chemical composition and morphology of these novel material architectures. Photocatalytic functionality of the synthesized materials was demonstrated both in gas phase as well as in liquid phase. Along these lines, air and water purification capabilities of the synthesized TiO{sub 2} microspheres were established by performing photocatalytic oxidative NOx(g) storage and Rhodamine B(aq) degradation experiments; respectively. The synthetic approach presented herein offers new opportunities to design and create sophisticated functional materials that can be used in micro reactor systems, adsorbents, drug delivery systems, catalytic processes, and sensor technologies.

  20. Controlled release profiles of dipyridamole from biodegradable microspheres on the base of poly(3-hydroxybutyrate.

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Novel biodegradable microspheres on the base of poly(3-hydroxybutyrate (PHB designed for controlled release of antithrombotic drug, namely dipyridamole (DPD, have been kinetically studied. The profiles of release from the microspheres with different diameters 4, 9, 63, and 92 µm present the progression of nonlinear and linear stages. Diffusionkinetic equation describing both linear (PHB hydrolysis and nonlinear (diffusion stages of the DPD release profiles from the spherical subjects has been written down as the sum of two terms: desorption from the homogeneous sphere in accordance with diffusion mechanism and the zero-order release. In contrast to the diffusivity dependence on microsphere size, the constant characteristics (k of linearity are scarcely affected by the diameter of PHB microparticles. The view of the kinetic profiles as well as the low rate of DPD release are in satisfactory agreement with kinetics of weight loss measured in vitro for the PHB films. Taking into account kinetic results, we suppose that the degradation of both films and PHB microspheres is responsible for the linear stage of DPD release profiles. In the nearest future, combination of biodegradable PHB and DPD as a representative of proliferation cell inhibitors will give possibility to elaborate the novel injectable therapeutic system for a local, long-term, antiproliferative action.

  1. Microscopic Analysis of Corn Fiber Using Corn Starch- and Cellulose-Specific Molecular Probes

    Energy Technology Data Exchange (ETDEWEB)

    Porter, S. E.; Donohoe, B. S.; Beery, K. E.; Xu, Q.; Ding, S.-Y.; Vinzant, T. B.; Abbas, C. A.; Himmel, M. E.

    2007-09-01

    Ethanol is the primary liquid transportation fuel produced from renewable feedstocks in the United States today. The majority of corn grain, the primary feedstock for ethanol production, has been historically processed in wet mills yielding products such as gluten feed, gluten meal, starch, and germ. Starch extracted from the grain is used to produce ethanol in saccharification and fermentation steps; however the extraction of starch is not 100% efficient. To better understand starch extraction during the wet milling process, we have developed fluorescent probes that can be used to visually localize starch and cellulose in samples using confocal microscopy. These probes are based on the binding specificities of two types of carbohydrate binding modules (CBMs), which are small substrate-specific protein domains derived from carbohydrate degrading enzymes. CBMs were fused, using molecular cloning techniques, to a green fluorescent protein (GFP) or to the red fluorescent protein DsRed (RFP). Using these engineered probes, we found that the binding of the starch-specific probe correlates with starch content in corn fiber samples. We also demonstrate that there is starch internally localized in the endosperm that may contribute to the high starch content in corn fiber. We also surprisingly found that the cellulose-specific probe did not bind to most corn fiber samples, but only to corn fiber that had been hydrolyzed using a thermochemical process that removes the residual starch and much of the hemicellulose. Our findings should be of interest to those working to increase the efficiency of the corn grain to ethanol process.

  2. Controlled Release of Chitosan and Sericin from the Microspheres-Embedded Wound Dressing for the Prolonged Anti-microbial and Wound Healing Efficacy.

    Science.gov (United States)

    Aramwit, Pornanong; Yamdech, Rungnapha; Ampawong, Sumate

    2016-05-01

    One approach in wound dressing development is to incorporate active molecules or drugs in the dressing. In order to reduce the frequency of dressing changes as well as to prolong wound healing efficacy, wound dressings that can sustain the release of the active molecules should be developed. In our previous work, we developed chitosan/sericin (CH/SS) microspheres that released sericin in a controlled rate. However, the difficulty of applying the microspheres that easily diffuse and quickly degrade onto the wound was its limitations. In this study, we aimed to develop wound dressing materials which are easier to apply and to provide extended release of sericin. Different amounts of CH/SS microspheres were embedded into various compositions of polyvinyl alcohol/gelatin (PVA/G) scaffolds and fabricated using freeze-drying and glutaraldehyde crosslinking techniques. The obtained CH/SS microspheres-embedded scaffolds with appropriate design and formulation were introduced as a wound dressing material. Sericin was released from the microspheres and the scaffolds in a sustained manner. Furthermore, an optimized formation of the microspheres-embedded scaffolds (2PVA2G+2CHSS) was shown to possess an effective antimicrobial activity against both gram-positive and gram-negative bacteria. These microspheres-embedded scaffolds were not toxic to L929 mouse fibroblast cells, and they did not irritate the tissue when applied to the wound. Finally, probably by the sustained release of sericin, these microspheres-embedded scaffolds could promote wound healing as well as or slightly better than a clinically used wound dressing (Allevyn®) in a mouse model. The antimicrobial CH/SS microspheres-embedded PVA/G scaffolds with sustained release of sericin would appear to be a promising candidate for wound dressing application.

  3. Effect of Punica granatum peel extracts on antimicrobial properties in Walnut shell cellulose reinforced Bio-thermoplastic starch films from cashew nut shells.

    Science.gov (United States)

    Harini, K; Chandra Mohan, C; Ramya, K; Karthikeyan, S; Sukumar, M

    2018-03-15

    The main aim of the present study is to extract and characterize cashew nut shell (CNS) starch and walnut shell cellulose (WNC) for development of cellulose reinforced starch films. Moreover, the extraction and characterization of pomegranate peel extract, for incorporation with CNS-WNC films, was investigated. CNS starch was examined to be a moderate amylose starch with 26.32 ± 0.43% amylose content. Thermal degradation temperature of CNS starch was found to be 310 °C. Walnut shell cellulose was found to have high crystallinity index of 72%, with two thermal degradation temperatures of 319 °C and 461 °C. 2% WN cellulose reinforced CNS starch films were examined to have good oxygen transfer rate, mechanical and physical properties. Thermal degradation temperature of CNS-WNC starch films were found to be at the range of 298-302 °C. Surface roughness of CNS-WNC starch films were found to be increasing with increase in concentration of cellulose in films. Hydroxymethylfurfurole, Benzene, 2-methoxy-1,3,4-trimethyl and 1,2,3-Propanetriol, 1-acetate were found to be major active compounds present in hydrophilic extracts of Punica granatum peels. 2% WN cellulose reinforced starch films infused with hydrophilic active compounds of pomegranate peel was examined to be having good active package properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. In vitro Evaluation of Nateglinide-Loaded Microspheres Formulated ...

    African Journals Online (AJOL)

    Purpose: To formulate and evaluate sustained release microspheres of nateglinide (NTG) for enhanced patient compliance. Methods: Nateglinide microspheres were prepared with varying proportions of biodegradable polymers (olibanum gum and guar gum) by calcium chloride/sodium alginate ionic gelation method.

  5. Chemical Modifications of Starch: Microwave Effect

    Directory of Open Access Journals (Sweden)

    Kamila Lewicka

    2015-01-01

    Full Text Available This paper presents basic methods of starch chemical modification, the effect of microwave radiation on the modification process, and the physicochemical properties of starch. It has been shown that the modifications contribute to improvement of the material performance and likewise to significant improvement of its mechanical properties. As a result, more and more extensive use of starch is possible in various industries. In addition, methods of oxidized starch and starch esters preparation are discussed. Properties of microwave radiation and its impact on starch (with particular regard to modifications described in literature are characterized.

  6. Effects on starch and amylolytic enzymes during Lepidium meyenii Walpers root storage.

    Science.gov (United States)

    Rondán-Sanabria, Gerby Giovanna; Valcarcel-Yamani, Beatriz; Finardi-Filho, Flavio

    2012-10-01

    The high water content in maca (Lepidium meyenii W.) roots combined with the damage produced during or after harvest makes them vulnerable to attack by enzymes and microorganisms. Although starch degradation has been extensively studied, in maca roots there is a paucity of research regarding the starch reserves. In this paper, parameters of starch degradation are shown to be related to the action of amylolytic enzymes during storage at room temperature. Over the course of three weeks, the starch and protein content, soluble sugar, total amylolytic activity, and α- and β-amylase activity were measured. In addition, the integrity of starch granules was observed by scanning electron microscopy. Despite the evidence of dehydration, there were no significant differences (p ≤ 0.5) in the total starch content or in the activities of α- and β-amylase. After the third week the roots remained suitable for consumption. The results indicate a postharvest latency that can lead to sprout or to senescence, depending on the environmental conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Direct conversion of starch to ethanol using recombınant Saccharomyces cerevisiae containing glucoamylase gene

    Science.gov (United States)

    Purkan, P.; Baktir, A.; Puspaningsih, N. N. T.; Ni'mah, M.

    2017-09-01

    Saccharomyces cerevisiae is known for its high fermentative capacity, high ethanol yield and its high ethanol tolerance. The yeast is inability converting starch (relatively inexpensive substrate) into biofuel ethanol. Insertion of glucoamylase gene in yeast cell of Saccharomyces cerevisiae had been done to increase the yeast function in ethanol fermentation from starch. Transformation of yeast of S. cerevisiae with recombinant plasmid yEP-GLO1 carrying gene encoding glucoamylase (GLO1) produced the recombinant yeast which enable to degrade starch. Optimizing of bioconversion process of starch into ethanol by the yeast of recombinant Saccharomyces cerevisiae [yEP-GLO1] had been also done. Starch concentration which could be digested by recombinant yeast of S. cerevisiae [yEP-GLO1] was 10% (w/v). Bioconversion of starch having concentration 10% (b/v) using recombinant yeast of S. cerevisiae BY5207 [yEP-GLO1] could result ethanol as 20% (v/v) to alcoholmeter and 19,5% (v/v) to gas of chromatography. Otherwise, using recombinant yeast S. cerevisiae S. cerevisiae AS3324 [yEP-GLO1] resulted ethanol as 17% (v/v) to alcoholmeter and 17,5% (v/v) to gas of chromatography. The highest ethanol in starch bioconversion using both recombinant yeasts BY5207 and AS3324 could be resulted on 144 hours of fermentation time as well as in pH 5.

  8. The influence of gamma irradiation on texture, color and viscosity properties of potato starch

    International Nuclear Information System (INIS)

    Teixeira, Bruna S.; Inamura, Patricia Y.; Mastro, Nelida L. del

    2015-01-01

    Food choices, while influenced by taste and nutritional value, have also symbolic enjoyment meanings. The texture, appearance, and flavor are important acceptability factors for any meal component. In our every day enjoyment of eating, texture is often as important as flavor. Starch is the most important source of carbohydrate in human nutrition and is widely used in many applications throughout the food industry. As an additive for food processing, food starches are typically used as thickeners and stabilizers in foods such as puddings, custards, soups, sauces, gravies, pie fillings, and salad dressings, and to make noodles and pastas. Potato starch is extracted from the root tubers of the potato plant. Radiation processing can be applied on foods for different purposes. It can also produce some modifications that are important to know. The aim of this research was to analyze the influence of gamma irradiation on texture, color and viscosity of potato starch. Starch samples were irradiated in a 60 Co source Gammacell 220 with doses of 0, 5, 10 and 15 kGy. The results obtained showed that texture became inversely proportional to the applied radiation dose. Increasing doses promoted a slight rise in the parameter b* (yellow color) while the parameter L was not significantly affected. On the other hand, the viscosity of potato starch aqueous preparations decreased with the radiation dose, attributable to some degradation of starch molecules. (author)

  9. The influence of gamma irradiation on texture, color and viscosity properties of potato starch

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Bruna S.; Inamura, Patricia Y.; Mastro, Nelida L. del, E-mail: brunasaporito@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Food choices, while influenced by taste and nutritional value, have also symbolic enjoyment meanings. The texture, appearance, and flavor are important acceptability factors for any meal component. In our every day enjoyment of eating, texture is often as important as flavor. Starch is the most important source of carbohydrate in human nutrition and is widely used in many applications throughout the food industry. As an additive for food processing, food starches are typically used as thickeners and stabilizers in foods such as puddings, custards, soups, sauces, gravies, pie fillings, and salad dressings, and to make noodles and pastas. Potato starch is extracted from the root tubers of the potato plant. Radiation processing can be applied on foods for different purposes. It can also produce some modifications that are important to know. The aim of this research was to analyze the influence of gamma irradiation on texture, color and viscosity of potato starch. Starch samples were irradiated in a {sup 60}Co source Gammacell 220 with doses of 0, 5, 10 and 15 kGy. The results obtained showed that texture became inversely proportional to the applied radiation dose. Increasing doses promoted a slight rise in the parameter b* (yellow color) while the parameter L was not significantly affected. On the other hand, the viscosity of potato starch aqueous preparations decreased with the radiation dose, attributable to some degradation of starch molecules. (author)

  10. [Analysis of the character of film decomposition of starch acetate (SA) coated urea by infrared spectrum].

    Science.gov (United States)

    Li, Dong-Po; Wu, Zhi-Jie; Liang, Cheng-Hua; Chen, Li-Jun; Zhang, Yu-Lan; Nie, Yan-Xia

    2012-06-01

    The degradability characteristics of film with 4 kinds of starch acetate coated and inhibitors amended urea were analyzed by FTIR, which was purposed to supply theoretical basis for applying starch acetate coated urea fertilizers in farming. The result showed that the chemical component, molecule structure and material form of the membrane were not changed because of adding different inhibitors to urea. The main peaks of the film degradation process were brought by the H--O, --OH, CO2, C==O, --CH2, --CH3, C--O, C--O--H and C--O--C vibrancy in asymmetry and symmetry. In brown soil, the trend of absorbing value of the most high peak was 0>15>30>60>90>120>150>310 d. The infrared spectra of 4 kinds of fertilizers were not different remarkably, and the film was comparatively slowly degraded before 15 d. But a majority of the film had been already degraded after 150 days. The main components of film materials were degraded fastest in 310 days. The speed of film degradation wasn't more impacted by different inhibitors. The characteristic of starch acetate film degradation may be monitored entirely and degradation speed difference of the film could be represented through infrared spectrum.

  11. Preparation and Characterization of Sugar Cane Wax Microspheres ...

    African Journals Online (AJOL)

    ... and characterize indomethacin (IM) microspheres prepared with sugar cane wax microsperes. Methods: Microspheres were prepared by melt-emulsified dispersion and cooling-induced solidification method. The microspheres were characterized by scanning electron microscopy (SEM) and differntial scanning calorimetry ...

  12. Preparation of polymer microspheres by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Naka, Y.; Yamamoto, Y.; Yoshida, Y.; Tagawa, S.

    1995-01-01

    Cross-liking monomer, diethylene glycol dimethacrylate gives microspheres from organic solution by radiation-induced polymerization. /One of the remarkable result is that the number of the microspheres is not changing during the polymerization. Ethyl methacrylate, maleic anhydride, styrene and acrylamide are used as comonomers. These comonomers give the microspheres in the range of 0 to 0.4 as mol fractions. (author)

  13. Preparation and characterization of dialdehyde starch urea (DASU ...

    African Journals Online (AJOL)

    Dialdehyde starch urea (DASU) was prepared by the reaction of dialdehyde starch (DAS) from periodate oxidized cassava starch with urea, which was then used to adsorb Co(II), Pb(II) and Zn(II) ions from aqueous solution. Starch modified starches and starch complexes were characterized by Fourier transform infrared ...

  14. Accelerated in vitro release testing method for naltrexone loaded PLGA microspheres.

    Science.gov (United States)

    Andhariya, Janki V; Choi, Stephanie; Wang, Yan; Zou, Yuan; Burgess, Diane J; Shen, Jie

    2017-03-30

    The objective of the present study was to develop a discriminatory and reproducible accelerated release testing method for naltrexone loaded parenteral polymeric microspheres. The commercially available naltrexone microsphere product (Vivitrol ® ) was used as the testing formulation in the in vitro release method development, and both sample-and-separate and USP apparatus 4 methods were investigated. Following an in vitro drug stability study, frequent media replacement and addition of anti-oxidant in the release medium were used to prevent degradation of naltrexone during release testing at "real-time" (37°C) and "accelerated" (45°C), respectively. The USP apparatus 4 method was more reproducible than the sample-and-separate method. In addition, the accelerated release profile obtained using USP apparatus 4 had a shortened release duration (within seven days), and good correlation with the "real-time" release profile. Lastly, the discriminatory ability of the developed accelerated release method was assessed using compositionally equivalent naltrexone microspheres with different release characteristics. The developed accelerated USP apparatus 4 release method was able to detect differences in the release characteristics of the prepared naltrexone microspheres. Moreover, a linear correlation was observed between the "real-time" and accelerated release profiles of all the formulations investigated, suggesting that the release mechanism(s) may be similar under both conditions. These results indicate that the developed accelerated USP apparatus 4 method has the potential to be an appropriate fast quality control tool for long-acting naltrexone PLGA microspheres. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Resistant starch content, in vitro starch digestibility and physico-chemical properties of flour and starch from Thai bananas

    Directory of Open Access Journals (Sweden)

    Nednapis Vatanasuchart

    2012-07-01

    Full Text Available Flour and starch were prepared from six Thai banana cultivars: Kluai Hom, Kluai Khai,Kluai Lebmuenang, Kluai Namwa, Kluai Hakmuk and Kluai Hin, and their resistant starch (RS, invitro starch digestibility and physico-chemical properties were determined. The RS content of theflour is 52.2-68.1%, with flour from Kluai Hin containing the highest amount of RS, followed by thatfrom Kluai Hakmuk. The starch has a higher RS content (70.1-79.2%, the highest value comingfrom Kluai Hakmuk starch, followed by Kluai Hom starch. A significant linear relationship betweenapparent amylose and RS was observed. Interestingly, most of the flour showed a slower rate of invitro starch digestibility than that of the starch, with Kluai Hin flour exhibiting the slowest rate,followed by Kluai Namwa. Rapid viscosity analysis showed significantly higher peak viscosity of thestarch than the flour, the highest final and setback viscosity being obtained from Kluai Hin starch.Differential scanning calorimetry showed an endothermic transition enthalpy over a range of 17.4 J/gfor Kluai Lebmuenang starch to 18.6 J/g for Kluai Hin starch. X-ray diffractograms of the starchesexhibited a typical B-pattern with Kluai Hin showing the highest degree of relative crystallinity(31.3% with a sharp peak at 5.5. The overall results seemed to indicate an effect of the BBgenotype on the resistance of banana starch granules to enzymatic digestion due to amylosemolecules and the crystallinity of amylopectin.

  16. Rheological and microstructural properties of Irradiated starch

    International Nuclear Information System (INIS)

    Atrous Turki, Hager

    2011-01-01

    Gamma irradiation ia s fast and efficient method to improve the functional properties of straches. Wheat and potato starches were submitted, in the present study, at 3,5,10 and 20 kGy radiation dose. The changes induced by irradiation on the rheological properties of these starches showed a decrease in the viscosity with increasing radiation dose. Chemicals bond's hydrolysis has been induced by free radicals that have been identified by EPR. Wheat starch presents five EPR signals after irradiation, whiles potato starch has a weak EPR signal. On the other hand, irradiation caused decrease in amylose content. This decrease is more pronounced in potato starch. Dry irradiated starch's MEB revealed no change in the shape, size and distribution of the granules. While, the observation of wheat starch allowed the complete disappearance of the granular structure and the dissolution of its macromolecules after irradiation which justifies the significant decrease in wheat starch's viscosity irradiated at 20 kGy.

  17. Characterization of Digestion Resistance Sweet Potato Starch ...

    African Journals Online (AJOL)

    HP

    Purpose: To analyze the physicochemical properties and in vitro digestibility of sweet potato starch phosphodiester prepared using sodium trimetaphosphate. Methods: The physicochemical properties of sweet potato starch phosphodiester were analyzed by using infrared spectrometry (IR), differential scanning calorimetry ...

  18. Preparation and characterization of jackfruit seed starch/poly (vinyl alcohol) (PVA) blend film

    Science.gov (United States)

    Sarifuddin, N.; Shahrim, N. A.; Rani, N. N. S. A.; Zaki, H. H. M.; Azhar, A. Z. A.

    2018-01-01

    From the environmental point of view, biodegradable materials have been rapidly developed in the past years. PVA is one of the biodegradable synthetic polymers commonly used, but its degradation rate is slow. As an alternative to reduce plastic waste and accelerate the degradation process, PVA frequently blended with other natural polymers to improve its biodegradability. The natural polymer such as starch has high potential in enhancing PVA biodegradability by blending both components. The usage of starch extracted from agriculture wastes such as jackfruit seed is quite promising. In this study, jackfruit seed starch (JFSS)/poly (vinyl alcohol) (PVA) blend films were prepared using the solution casting method. The effect of starch content on the mechanical (tensile strength and elongation to break %) and physical properties of the tested films were investigated. The optimum tensile strength was obtained at 10.45 MPa when 4 wt. % of starch added to the blend. But, decreasing trend of tensile strength was found upon increasing the amount of starch beyond 4 wt. % in starch/PVA blend films. Nevertheless, elongation at break decreases with the increase in starch content. The mechanical properties of the blend films are supported by the Field Emission Scanning Electron Microscopy (FESEM), in which the native JFSS granules are wetted by PVA continuous phase with good dispersion and less agglomeration. The incorporation of JFSS in PVA has also resulted in the appearance of hydrogen bond peak, which evidenced by Fourier Transform Infrared (FTIR). Additionally, the biodegradation rate of JFSS/PVA was evaluated through soil burial test.

  19. Morphological analysis of thermoplastic starch films and montmorillonite (TPS/MMT) using vegetable oils of Brazilian Cerrado as plasticizers

    International Nuclear Information System (INIS)

    Schlemmer, Daniela; Sales, Maria Jose A.; Angelica, Romulo S.; Gomes, Ana Cristina M.M.

    2009-01-01

    Biopolymers can be used where petrochemical plastics have applications with short life. The excellent degradation of starch and its low cost make it an alternative for obtaining biodegradable plastics. To obtain thermoplastic starch (TPS) is necessary mechanical shake, high temperature and plasticizers. In this work, TPS were produced using three different vegetable oils from Brazilian's cerrado as plasticizers: buriti, macauba or pequi. Materials are also produced with montmorillonite (MMT). All the materials were analyzed by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The starch micrographs revealed irregular delaminate with a predominance of starch and 'holes' for the oils. In nanocomposites the clusters of clay are dispersed without a defined standard. It was understood that the plasticizers and processing completely changed the structure of starch causing a decrease in their crystallinity degree. Almost all nanocomposites presented exfoliate structure, only one presented intercalated structure. (author)

  20. Active self-healing encapsulation of vaccine antigens in PLGA microspheres

    Science.gov (United States)

    Desai, Kashappa-Goud H.; Schwendeman, Steven P.

    2013-01-01

    Herein, we describe the detailed development of a simple and effective method to microencapsulate vaccine antigens in poly(lactic-co-glycolic acid) (PLGA) by simple mixing of preformed active self-microencapsulating (SM) PLGA microspheres in a low concentration aqueous antigen solution at modest temperature (10-38 °C). Co-encapsulating protein-sorbing vaccine adjuvants and polymer plasticizers were used to “actively” load the protein in the polymer pores and facilitate polymer self-healing at temperature > hydrated polymer glass transition temperature, respectively. The microsphere formulation parameters and loading conditions to provide optimal active self-healing microencapsulation of vaccine antigen in PLGA was investigated. Active self-healing encapsulation of two vaccine antigens, ovalbumin and tetanus toxoid (TT), in PLGA microspheres was adjusted by preparing blank microspheres containing different vaccine adjuvant (aluminum hydroxide (Al(OH)3) or calcium phosphate). Active loading of vaccine antigen in Al(OH)3-PLGA microspheres was found to: a) increase proportionally with an increasing loading of Al(OH)3 (0.88-3 wt%) and addition of porosigen, b) decrease when the inner Al(OH)3/trehalose phase to 1 mL outer oil phase and size of microspheres was respectively > 0.2 mL and 63 μm, and c) change negligibly by PLGA concentration and initial incubation (loading) temperature. Encapsulation of protein sorbing Al(OH)3 in PLGA microspheres resulted in suppression of self-healing of PLGA pores, which was then overcome by improving polymer chain mobility, which in turn was accomplished by coincorporating hydrophobic plasticizers in PLGA. Active self-healing microencapsulation of manufacturing process-labile TT in PLGA was found to: a) obviate micronization- and organic solvent-induced TT degradation, b) improve antigen loading (1.4-1.8 wt% TT) and encapsulation efficiency (~ 97%), c) provide nearly homogeneous distribution and stabilization of antigen in polymer

  1. Effect of starch isolation method on properties of sweet potato starch

    Directory of Open Access Journals (Sweden)

    A. SURENDRA BABU

    2014-08-01

    Full Text Available Isolation method of starch with different agents influences starch properties, which provide attention for studying the most appropriate method for isolation of starch. In the present study sweet potato starch was isolated by Sodium metabisulphate (M1, Sodium chloride (M2, and Distilled water (M3 methods and these were assessed for functional, chemical, pasting and structural properties. M3 yielded the greatest recovery of starch (10.20%. Isolation methods significantly changed swelling power and pasting properties but starches exhibited similar chemical properties. Sweet potato starches possessed C-type diffraction pattern. Small size granules of 2.90 μm were noticed in SEM of M3 starch. A high degree positive correlation was found between ash, amylose, and total starch content. The study concluded that isolation methods brought changes in yield, pasting and structural properties of sweet potato starch.

  2. Biosensing by WGM Microspherical Resonators

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2016-06-01

    Full Text Available Whispering gallery mode (WGM microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed.

  3. Localized drugs delivery hydroxyapatite microspheres for osteoporosis therapy

    Science.gov (United States)

    Lee, J. H.; Ko, I. H.; Jeon, S.-H.; Chae, J. H.; Lee, E. J.; Chang, J. H.

    2011-10-01

    This study describes the preparation of hydroxyapatite microspheres for local drugs delivery. The formation of the hydroxyapatite microspheres was initiated by enzymatic decomposition of urea and accomplished by emulsification process (water-in-oil). The microspheres obtained were sintered at 500°C. Scanning electron microscope (SEM) indicated that the microspheres have various porous with random size, which maximizes the surface area. Cytotoxicity was not observed after sintering. Osteoporosis drugs, alendronate and BMP-2, were loaded into HAp microspheres and the releases of both molecules showed sustained releasing profiles.

  4. Acrolein Microspheres Are Bonded To Large-Area Substrates

    Science.gov (United States)

    Rembaum, Alan; Yen, Richard C. K.

    1988-01-01

    Reactive cross-linked microspheres produced under influence of ionizing radiation in aqueous solutions of unsaturated aldehydes, such as acrolein, with sodium dodecyl sulfate. Diameters of spheres depend on concentrations of ingredients. If polystyrene, polymethylmethacrylate, or polypropylene object immersed in solution during irradiation, microspheres become attached to surface. Resulting modified surface has grainy coating with reactivity similar to free microspheres. Aldehyde-substituted-functional microspheres react under mild conditions with number of organic reagents and with most proteins. Microsphere-coated macrospheres or films used to immobilize high concentrations of proteins, enzymes, hormones, viruses, cells, and large number of organic compounds. Applications include separation techniques, clinical diagnostic tests, catalytic processes, and battery separators.

  5. Modification of mechanical and thermal property of chitosan–starch blend films

    International Nuclear Information System (INIS)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M.E.; Khan, Ruhul A.; Dafader, N.C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-01-01

    Chitosan–starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan–starch films. Water uptake of the films reduced significantly than the pure chitosan–starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively. - Highlights: ► Chitosan–starch blend films (thickness 0.2 mm) were prepared by casting. ► To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. ► Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. ► Properties of the modified films such as tensile strength, elongation at break, water uptake, TGA, DMA, SEM, FTIR were studied. ► Results indicate that modification of chitosan–starch film with mustard oil improved the properties of the blend films which could be further modified by HEMA using gamma radiation.

  6. Lineage-specific Evolutionary Histories and Regulation of Major Starch Metabolism Genes during Banana Ripening

    Directory of Open Access Journals (Sweden)

    Cyril Jourda

    2016-12-01

    Full Text Available Starch is the most widespread and abundant storage carbohydrate in plants. It is also a major feature of cultivated bananas as it accumulates to large amounts during banana fruit development before almost complete conversion to soluble sugars during ripening. Little is known about the structure of major gene families involved in banana starch metabolism and their evolution compared to other species. To identify genes involved in banana starch metabolism and investigate their evolutionary history, we analyzed six gene families playing a crucial role in plant starch biosynthesis and degradation: the ADP-glucose pyrophosphorylases (AGPases, starch synthases (SS, starch branching enzymes (SBE, debranching enzymes (DBE, -amylases (AMY and -amylases (BAM. Using comparative genomics and phylogenetic approaches, these genes were classified into families and sub-families and orthology relationships with functional genes in Eudicots and in grasses were identified. In addition to known ancestral duplications shaping starch metabolism gene families, independent evolution in banana and grasses also occurred through lineage-specific whole genome duplications for specific sub-families of AGPases, SS, SBE and BAM genes; and through gene-scale duplications for AMY genes. In particular, banana lineage duplications yielded a set of AGPases, SBE and BAM genes that were highly or specifically expressed in banana fruits. Gene expression analysis highlighted a complex transcriptional reprogramming of starch metabolism genes during ripening of banana fruits. A differential regulation of expression between banana gene duplicates was identified for SBE and BAM genes, suggesting that part of starch metabolism regulation in the fruit evolved in the banana lineage

  7. ( Phaseolus lunatus ) starch as a tablet disintegrant

    African Journals Online (AJOL)

    ) was evaluated. The starch from the seeds was extracted and its disintegrant ability was compared with that of maize starch BP in paracetamol based tablets at concentrations of 0, 2.5, 5, 7.5 and 10 %w/w. The following properties of the starch ...

  8. Sugarcane starch: quantitative determination and characterization

    Directory of Open Access Journals (Sweden)

    Joelise de Alencar Figueira

    2011-09-01

    Full Text Available Starch is found in sugarcane as a storage polysaccharide. Starch concentrations vary widely depending on the country, variety, developmental stage, and growth conditions. The purpose of this study was to determine the starch content in different varieties of sugarcane, between May and November 2007, and some characteristics of sugarcane starch such as structure and granules size; gelatinization temperature; starch solution filterability; and susceptibility to glucoamylase, pullulanase, and commercial bacterial and fungal α-amylase enzymes. Susceptibility to debranching amylolytic isoamylase enzyme from Flavobacterium sp. was also tested. Sugarcane starch had spherical shape with a diameter of 1-3 µm. Sugarcane starch formed complexes with iodine, which showed greater absorption in the range of 540 to 620 nm. Sugarcane starch showed higher susceptibility to glucoamylase compared to that of waxy maize, cassava, and potato starch. Sugarcane starch also showed susceptibility to debranching amylolytic pullulanases similar to that of waxy rice starch. It also showed susceptibility to α-amylase from Bacillus subtilis, Bacillus licheniformis, and Aspergillus oryzae similar to that of the other tested starches producing glucose, maltose, maltotriose, maltotetraose, maltopentose and limit α- dextrin.

  9. Kinetic modelling of enzymatic starch hydrolysis

    NARCIS (Netherlands)

    Bednarska, K.A.

    2015-01-01

    Kinetic modelling of enzymatic starch hydrolysis – a summary

    K.A. Bednarska

    The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

  10. Properties of retrograded and acetylated starch produced via starch extrusion or starch hydrolysis with pullulanase.

    Science.gov (United States)

    Kapelko, M; Zięba, T; Gryszkin, A; Styczyńska, M; Wilczak, A

    2013-09-12

    The aim of the present study was to determine the impact of serial modifications of starch, including firstly starch extrusion or hydrolysis with pullulanase, followed by retrogradation (through freezing and defrosting of pastes) and acetylation (under industrial conditions), on its susceptibility to amylolysis. The method of production had a significant effect on properties of the resultant preparations, whilst the direction and extent of changes depended on the type of modification applied. In the produced starch esters, the degree of substitution, expressed by the per cent of acetylation, ranged from 3.1 to 4.4 g/100 g. The acetylation had a significant impact on contents of elements determined with the atomic emission spectrometry, as it contributed to an increased Na content and decreased contents of Ca and K. The DSC thermal characteristics enabled concluding that the modifications caused an increase in temperatures and a decrease in heat of transition (or its lack). The acetylation of retrograded starch preparations increased their solubility in water and water absorbability. The modifications were found to exert various effects on the rheological properties of pastes determined based on the Brabender's pasting characteristics and flow curves determined with the use of an oscillatory-rotating viscosimeter. All starch acetates produced were characterized by ca. 40% resistance to amylolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Oral Digestion and Perception of Starch: Effects of Cooking, Tasting Time, and Salivary α-Amylase Activity.

    Science.gov (United States)

    Lapis, Trina J; Penner, Michael H; Balto, Amy S; Lim, Juyun

    2017-10-01

    Since starch is a significant part of human diet, its oral detection would be highly beneficial. This study was designed to determine whether starch or its degradation products can be tasted and what factors influence its perception. Subjects were asked 1) to taste 8% raw and cooked starch samples for 5, 15, and 35 s and rate perceived intensities of sweetness and "other" taste (i.e., other than sweet), 2) to donate saliva to obtain salivary flow rate (mg/s) and salivary α-amylase activity (per mg saliva), and 3) to fill out a carbohydrate consumption survey. Subsequently, in vitro hydrolysis of starch was performed; saliva was collected from 5 subjects with low and high amylase activities and reacted with 8% raw and cooked starch at 2, 15, and 30 s. Hydrolysis products were then quantified using a High performance liquid chromatography. The results showed cooking increased the digestibility of starch such that the amount of hydrolysis products increased with reaction time. However, cooking did not influence taste ratings, nor were they influenced by tasting time. Subjects' salivary amylase activities were associated with the efficacy of their saliva to degrade starch, in particular cooked starch, and thus the amount of maltooligosaccharide products generated. Effective α-amylase activity [i.e. α-amylase activity (per mg saliva) × salivary flow rate (mg/s)] and carbohydrate consumption score (i.e. consumption frequency × number of servings) were also independently associated with sensory taste ratings. Human perception of starch is undoubtedly complex as shown in this study; the data herein point to the potential roles of salivary α-amylase activity and carbohydrate consumption in the perception of cooked starch. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Physicochemical properties of starches isolated from pumpkin compared with potato and corn starches.

    Science.gov (United States)

    Przetaczek-Rożnowska, Izabela

    2017-08-01

    The aim of the study was to characterize the selected physicochemical, thermal and rheological properties of pumpkin starches and compared with the properties of potato and corn starches used as control samples. Pumpkin starches could be used in the food industry as a free gluten starch. Better thermal and rheological properties could contribute to reduce the costs of food production. The syneresis of pumpkin starches was similar to that of potato starch but much lower than that for corn starch. Pasting temperatures of pumpkin starches were lower by 17-21.7°C and their final viscosities were over 1000cP higher than corn paste, but were close to the values obtained for potato starch. The thermodynamic characteristic showed that the transformation temperatures of pumpkin starches were lower than those measured for control starches. A level of retrogradation was much lower in pumpkin starch pastes (32-48%) than was in the case of corn (59%) or potato (77%) starches. The pumpkin starches gels were characterized by a much greater hardness, cohesiveness and chewiness, than potato or corn starches gels. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. A microsphere suspension model of metamaterial fluids

    Directory of Open Access Journals (Sweden)

    Qian Duan

    2017-05-01

    Full Text Available Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model to realize a metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in a low-ε insulating oil, the structured fluid exhibits liquid-like properties from dispersing phase as well as the isotropic negative electromagnetic parameters caused by Mie resonances from dispersed microspheres. The work presented here will benefit the development of structured fluids toward metamaterials.

  14. Overcoming hydrolysis of raw corn starch under industrial conditions with Bacillus licheniformis ATCC 9945a α-amylase.

    Science.gov (United States)

    Šokarda Slavić, Marinela; Pešić, Milja; Vujčić, Zoran; Božić, Nataša

    2016-03-01

    α-Amylase from Bacillus licheniformis ATCC 9945a (BliAmy) was proven to be very efficient in hydrolysis of granular starch below the temperature of gelatinization. By applying two-stage feeding strategy to achieve high-cell-density cultivation of Escherichia coli and extracellular production of BliAmy, total of 250.5 U/mL (i.e. 0.7 g/L) of enzyme was obtained. Thermostability of amylase was exploited to simplify purification. The hydrolysis of concentrated raw starch was optimized using response surface methodology. Regardless of raw starch concentration tested (20, 25, 30 %), BliAmy was very effective, achieving the final hydrolysis degree of 91 % for the hydrolysis of 30 % starch suspension after 24 h. The major A-type crystalline structure and amorphous domains of the starch granule were degraded at the same rates, while amylose-lipid complexes were not degraded. BliAmy presents interesting performances on highly concentrated solid starch and could be of value for starch-consuming industries while response surface methodology (RSM) could be efficiently applied for the optimization of the hydrolysis.

  15. Effects of β-Glucans and resistant starch on fermentation of recalcitrant fibers in growing pigs

    NARCIS (Netherlands)

    Vries, de S.; Gerrits, W.J.J.; Kabel, M.A.; Zijlstra, Ruurd; Vasanthan, Thava

    2017-01-01

    Effects of the presence of β-glucans and resistant starch in diets on nutrient and fiber degradability of rapeseed meal [RSM] (Brassica napus) and Distillers Dried Grain with Solubles (DDGS) were tested in a 2 × 3 factorial arrangement. Two basal diets, containing either 500 g/kg RSM or DDGS and

  16. Preparation of Nano-TiO₂-Coated SiO₂ Microsphere Composite Material and Evaluation of Its Self-Cleaning Property.

    Science.gov (United States)

    Sun, Sijia; Deng, Tongrong; Ding, Hao; Chen, Ying; Chen, Wanting

    2017-11-03

    In order to improve the dispersion of nano-TiO₂ particles and enhance its self-cleaning properties, including photocatalytic degradation of pollutants and surface hydrophilicity, we prepared nano-TiO₂-coated SiO₂ microsphere composite self-cleaning materials (SiO₂-TiO₂) by co-grinding SiO₂ microspheres and TiO₂ soliquid and calcining the ground product. The structure, morphology, and self-cleaning properties of the SiO₂-TiO₂ were characterized. The characterization results showed that the degradation efficiency of methyl orange by SiO₂-TiO₂ was 97%, which was significantly higher than that obtained by pure nano-TiO₂. The minimum water contact angle of SiO₂-TiO₂ was 8°, indicating strong hydrophilicity and the good self-cleaning effect. The as-prepared SiO₂-TiO₂ was characterized by the nano-TiO₂ particles uniformly coated on the SiO₂ microspheres and distributed in the gap among the microspheres. The nano-TiO₂ particles were in an anatase phase with the particle size of 15-20 nm. The nano-TiO₂ particles were combined with SiO₂ microspheres via the dehydroxylation of hydroxyl groups on their surfaces.

  17. Cassava starch in the Brazilian food industry

    Directory of Open Access Journals (Sweden)

    Ivo Mottin Demiate

    2011-06-01

    Full Text Available Cassava starch is a valued raw material for producing many kinds of modified starches for food applications. Its physicochemical properties, as well as its availability, have made it an interesting and challenging ingredient for the food industry. In the present work, food grade modified cassava starches were purchased from producers and analyzed for selected physicochemical characteristics. Samples of sour cassava starch were included, as well as one sample of native cassava starch. Results showed that almost all modified starches were resistant to syneresis, produced pastes more stable to stirred cooking, and some of them were difficult to cook. The sour cassava starches presented high acidity and resulted in clear and unstable pastes during stirred cooking, susceptible to syneresis.

  18. Preparation, characterization and utilization of starch nanoparticles.

    Science.gov (United States)

    Kim, Hee-Young; Park, Sung Soo; Lim, Seung-Taik

    2015-02-01

    Starch is one of the most abundant biopolymers in nature and is typically isolated from plants in the form of micro-scale granules. Recent studies reported that nano-scale starch particles could be readily prepared from starch granules, which have unique physical properties. Because starch is environmentally friendly, starch nanoparticles are suggested as one of the promising biomaterials for novel utilization in foods, cosmetics, medicines as well as various composites. An overview of the most up-to-date information regarding the starch nanoparticles including the preparation processes and physicochemical characterization will be presented in this review. Additionally, the prospects and outlooks for the industrial utilization of starch nanoparticles will be discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Mechanical, barrier and morphological properties of starch nanocrystals-reinforced pea starch films.

    Science.gov (United States)

    Li, Xiaojing; Qiu, Chao; Ji, Na; Sun, Cuixia; Xiong, Liu; Sun, Qingjie

    2015-05-05

    To characterize the pea starch films reinforced with waxy maize starch nanocrystals, the mechanical, water vapor barrier and morphological properties of the composite films were investigated. The addition of starch nanocrystals increased the tensile strength of the composite films, and the value of tensile strength of the composite films was highest when starch nanocrystals content was 5% (w/w). The moisture content (%), water vapor permeability, and water-vapor transmission rate of the composite films significantly decreased as starch nanocrystals content increased. When their starch nanocrystals content was 1-5%, the starch nanocrystals dispersed homogeneously in the composite films, resulting in a relatively smooth and compact film surface and better thermal stability. However, when starch nanocrystals content was more than 7%, the starch nanocrystals began to aggregate, which resulted in the surface of the composite films developing a longitudinal fibrous structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Physicochemical properties of starches and proteins in alkali-treated mungbean and cassava starch granules.

    Science.gov (United States)

    Israkarn, Kamolwan; Na Nakornpanom, Nantarat; Hongsprabhas, Parichat

    2014-05-25

    This study explored the influences of envelope integrity of cooked starch granules on physicochemical and thermophysical properties of mungbean and cassava starches. Alkali treatment was used to selectively leach amylose from the amorphous region of both starches and partially fragmented starch molecules into lower-molecular-weight polymers. It was found that despite the loss of 40% of the original content of amylose, both mungbean and cassava starches retained similar crystallinities, gelatinization temperature ranges, and pasting profiles compared to the native starches. However, the loss of granule-bound starch synthases during alkali treatment and subsequent alkali cooking in excess water played significant roles in determining granular disintegration. The alterations in envelope integrity due to the negative charge repulsion among polymers within the envelope of swollen granules, and the fragmentation of starch molecules, were responsible for the alterations in thermophysical properties of mungbean and cassava starches cooked under alkaline conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Engineering Saccharomyces cerevisiae for direct conversion of raw, uncooked or granular starch to ethanol.

    Science.gov (United States)

    Görgens, Johann F; Bressler, David C; van Rensburg, Eugéne

    2015-01-01

    The production of raw starch-degrading amylases by recombinant Saccharomyces cerevisiae provides opportunities for the direct hydrolysis and fermentation of raw starch to ethanol without cooking or exogenous enzyme addition. Such a consolidated bioprocess (CBP) for raw starch fermentation will substantially reduce costs associated with energy usage and commercial granular starch hydrolyzing (GSH) enzymes. The core purpose of this review is to provide comprehensive insight into the physiological impact of recombinant amylase production on the ethanol-producing yeast. Key production parameters, based on outcomes from modifications to the yeast genome and levels of amylase production, were compared to key benchmark data. In turn, these outcomes are of significance from a process point of view to highlight shortcomings in the current state of the art of raw starch fermentation yeast compared to a set of industrial standards. Therefore, this study provides an integrated critical assessment of physiology, genetics and process aspects of recombinant raw starch fermenting yeast in relation to presently used technology. Various approaches to strain development were compared on a common basis of quantitative performance measures, including the extent of hydrolysis, fermentation-hydrolysis yield and productivity. Key findings showed that levels of α-amylase required for raw starch hydrolysis far exceeded enzyme levels for soluble starch hydrolysis, pointing to a pre-requisite for excess α-amylase compared to glucoamylase for efficient raw starch hydrolysis. However, the physiological limitations of amylase production by yeast, requiring high biomass concentrations and long cultivation periods for sufficient enzyme accumulation under anaerobic conditions, remained a substantial challenge. Accordingly, the fermentation performance of the recombinant S. cerevisiae strains reviewed in this study could not match the performance of conventional starch fermentation processes

  2. Mechanical properties and solubility in water of corn starch-collagen composite films: Effect of starch type and concentrations.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Liu, Anjun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana

    2017-02-01

    This study investigated the possibility of enhancing the properties of collagen with three different maize starches: waxy maize starch, normal starch, and high amylose starch. Scanning electron microscopy images revealed that starch-collagen films had a rougher surface compared to pure collagen films which became smoother upon heating. Amylose starch and normal starch increased the tensile strength of unheated collagen films in both dry and wet states, while all starches increased tensile strength of collagen film by heating. Depending upon the amylose content and starch concentrations, film solubility in water decreased with the addition of starch. DSC thermograms demonstrated that addition of all starches improved the thermal stability of the collagen film. Moreover, X-ray diffraction results indicated that except for high amylose starch, the crystallinity of both starch and collagen was significantly decreased when subject to heating. FTIR spectra indicated that intermolecular interactions between starch and collagen were enhanced upon heating. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. ENZYME RESISTANCE OF GENETICALLY MODIFIED STARCH POTATOES

    Directory of Open Access Journals (Sweden)

    A. Sh. Mannapova

    2015-01-01

    Full Text Available Here in this article the justification of expediency of enzyme resistant starch use in therapeutic food products is presented . Enzyme resistant starch is capable to resist to enzymatic hydrolysis in a small intestine of a person, has a low glycemic index, leads to decrease of postprandial concentration of glucose, cholesterol, triglycerides in blood and insulin reaction, to improvement of sensitivity of all organism to insulin, to increase in sense of fulness and to reduction of adjournment of fats. Resistant starch makes bifidogenшс impact on microflora of a intestine of the person, leads to increase of a quantity of lactobacillus and bifidobacterium and to increased production of butyric acid in a large intestine. In this regard the enzyme resistant starch is an important component in food for prevention and curing of human diseases such as diabetes, obesity, colitis, a cancer of large and direct intestine. One method is specified by authors for imitation of starch digestion in a human body. This method is based on the definition of an enzyme resistance of starch in vitro by its hydrolysis to glucose with application of a glucoamylase and digestive enzyme preparation Pancreatin. This method is used in researches of an enzyme resistance of starch, of genetically modified potato, high amylose corn starch Hi-Maize 1043 and HYLON VII (National Starch Food Innovation, USA, amylopectin and amylose. It is shown that the enzyme resistance of the starch emitted from genetically modified potatoes conforms to the enzyme resistance of the high amylose corn starch “Hi-Maize 1043 and HYLON VII starch”, (National Starch Food Innovation, the USA relating to the II type of enzyme resistant starch. It is established that amylopectin doesn't have the enzyme resistant properties. The results of researches are presented. They allow us to make the following conclusion: amylose in comparison with amylopectin possesses higher enzyme resistance and gives to

  4. Structuring of diamond films using microsphere lithography

    Czech Academy of Sciences Publication Activity Database

    Domonkos, Mária; Ižák, Tibor; Štolcová, L.; Proška, J.; Demo, Pavel; Kromka, Alexander

    2014-01-01

    Roč. 54, č. 5 (2014), s. 320-324 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : nanostructuring * diamond thin films * polystyrene microspheres * reactive ion etching * scanning electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism

  5. Synthesis of polycaprolactone/nano hydroxyapatite microspheres

    International Nuclear Information System (INIS)

    Sampaio, Greyce Y.H.; Souza, Mairly K. da S.; Melo, Rafaela Q. da C.; Carrodeguas, Raul G.; Fook, Marcus V.L.

    2015-01-01

    Polycaprolactone(PCL)/nano hydroxyapatite(nHA) microspheres are advantageous material for manufacturing tridimensional scaffolds and formulating drug delivery systems for bone regeneration. The work was aimed to study the effect of processing variables on the properties of PCL/nHA microspheres. nHA was produced by precipitation method and was obtained calcium deficient nanoparticles consisted of nanorods (∼47 nm x ∼8 nm), according to the results of XRD, FTIR and TEM. PCL/nHA microspheres was produced by solid-in-oil-in-water emulsion solvent evaporation method. The variables studied were concentration of PCL (5,7.5 and 10 % w/v), nHA addition (17, 23 and 28.5% m/m) and surface treatment of nHA with stearic acid (AE). PCL/nHA microspheres were characterized by XRD, FTIR, SEM and TGA. The best result was obtained with a PCL concentration of 10% (w/v) and 23 % (m/m) of modified nHA. Solid PCL/nHA particles ranging 30-70 μm and containing 14 % of nHA dispersed in the polymer matrix were obtained, with agglomerates of nHA raging 5 -15 μm. These results suggest the promising use of this material in bone regeneration devices. (author)

  6. MICROSPHERE SIZE INFLUENCES THE FOREIGN BODY REACTION

    NARCIS (Netherlands)

    Zandstra, J.; Hiemstra, C.; Petersen, A. H.; Zuidema, J.; van Beuge, M. M.; Rodriguez, S.; Lathuile, A. A. R.; Veldhuis, G. J.; Steendam, R.; Bank, R. A.; Popa, E. R.

    2014-01-01

    Biodegradable poly-(DL-lactide-co-glycolide) (PLGA) microspheres (MSP) are attractive candidate vehicles for site-specific or systemic sustained release of therapeutic compounds. This release may be altered by the host's foreign body reaction (FBR), which is dependent on the characteristics of the

  7. Preparation of microstructured hydroxyapatite microspheres using ...

    Indian Academy of Sciences (India)

    Unknown

    Indian Academy of Sciences. 383. Preparation of microstructured hydroxyapatite microspheres using oil in water emulsions. T S PRADEESH, M C SUNNY, H K VARMA and P RAMESH*. Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology,. Thiruvananthapuram 695 012, India.

  8. Method and apparatus for producing microspherical particles

    International Nuclear Information System (INIS)

    Egli, W.; Bailey, W.H.; Leary, D.F.; Lansley, R.J.

    1979-01-01

    This invention relates generally to a method and apparatus for producing microspherical particles and more particularly to a method and apparatus which are particularly useful in connection with the sol-gel process for the production of nuclear fuel kernels. (U.K.)

  9. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    Science.gov (United States)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  10. Evaluation of Controlled Release Theophylline Microspheres ...

    African Journals Online (AJOL)

    Erah

    The microencapsulation technique by solvent evaporation process has been extensively studied in recent years for the preparation of microspheres. This is a complex process and requires strict control of several processing parameters such as rate of solvent evaporation, stirring rate, viscosity of polymeric phase, drug ...

  11. Encapsulated PDMS microspheres with reactive handles

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Ma, Baoguang; Li, Li

    2014-01-01

    Cured poly(dimethyl siloxane) microspheres are prepared by an emulsion polymerization reaction of silicone droplets in a continuous aqueous phase. The commonly used PDMS elastomer, Sylgard 184 from Dow Corning, is used as the dispersed phase. PDMS is polymerized and cross-linked by reacting vinyl...

  12. Barley grain constituents, starch composition, and structure affect starch in vitro enzymatic hydrolysis.

    Science.gov (United States)

    Asare, Eric K; Jaiswal, Sarita; Maley, Jason; Båga, Monica; Sammynaiken, Ramaswami; Rossnagel, Brian G; Chibbar, Ravindra N

    2011-05-11

    The relationship between starch physical properties and enzymatic hydrolysis was determined using ten different hulless barley genotypes with variable carbohydrate composition. The ten barley genotypes included one normal starch (CDC McGwire), three increased amylose starches (SH99250, SH99073, and SB94893), and six waxy starches (CDC Alamo, CDC Fibar, CDC Candle, Waxy Betzes, CDC Rattan, and SB94912). Total starch concentration positively influenced thousand grain weight (TGW) (r(2) = 0.70, p starch concentration (r(2) = -0.80, p hydrolysis of pure starch (r(2) = -0.67, p starch concentration (r(2) = 0.46, p starch (RS) in meal and pure starch samples. The rate of starch hydrolysis was high in pure starch samples as compared to meal samples. Enzymatic hydrolysis rate both in meal and pure starch samples followed the order waxy > normal > increased amylose. Rapidly digestible starch (RDS) increased with a decrease in amylose concentration. Atomic force microscopy (AFM) analysis revealed a higher polydispersity index of amylose in CDC McGwire and increased amylose genotypes which could contribute to their reduced enzymatic hydrolysis, compared to waxy starch genotypes. Increased β-glucan and dietary fiber concentration also reduced the enzymatic hydrolysis of meal samples. An average linkage cluster analysis dendrogram revealed that variation in amylose concentration significantly (p starch concentration in meal and pure starch samples. RS is also associated with B-type granules (5-15 μm) and the amylopectin F-III (19-36 DP) fraction. In conclusion, the results suggest that barley genotype SH99250 with less decrease in grain weight in comparison to that of other increased amylose genotypes (SH99073 and SH94893) could be a promising genotype to develop cultivars with increased amylose grain starch without compromising grain weight and yield.

  13. Encapsulating fatty acid esters of bioactive compounds in starch

    Science.gov (United States)

    Lay Ma, Ursula Vanesa

    Interest in the use of many bioactive compounds in foods is growing in large part because of the apparent health benefits of these molecules. However, many of these compounds can be easily degraded during processing, storage, or their passage through the gastrointestinal tract before reaching the target site. In addition, they can be bitter, acrid, or astringent, which may negatively affect the sensory properties of the product. Encapsulation of these molecules may increase their stability during processing, storage, and in the gastrointestinal tract, while providing controlled release properties. The ability of amylose to form inclusion complexes and spherulites while entrapping certain compounds has been suggested as a potential method for encapsulation of certain molecules. However, complex formation and spherulitic crystallization are greatly affected by the type of inclusion molecules, type of starch, and processing conditions. The objectives of the present investigation were to: (a) study the effect of amylose, amylopectin, and intermediate material on spherulite formation and its microstructure; (b) investigate the formation of amylose and high amylose starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters; (c) evaluate the ability of spherulites to form in the presence of fatty acid esters and to entrap ascorbyl palmitate, retinyl palmitate, and phytosterol esters; and (d) evaluate the effect of processing conditions on spherulite formation and fatty acid ester entrapment. Higher ratios of linear to branched molecules resulted in the formation of more and rounder spherulites with higher heat stability. In addition to the presence of branches, it appears that spherulitic crystallization is also affected by other factors, such as degree of branching, chain length, and chain length distribution. Amylose and Hylon VII starch formed inclusion complexes with fatty acid esters of ascorbic acid, retinol, or phytosterols

  14. Preparation and properties of novel melt-blended halloysite nanotubes/wheat starch nanocomposites.

    Science.gov (United States)

    Schmitt, H; Prashantha, K; Soulestin, J; Lacrampe, M F; Krawczak, P

    2012-07-01

    Novel bionanocomposites based on halloysite nanotubes as nanofillers and plasticized starch as polymeric matrix were successfully prepared by melt-extrusion for the first time. Both modified and non modified halloysites were added at different weight contents. The structural, morphological, thermal and mechanical properties of plasticized starch/halloysites nanocomposites were investigated. Melt-compounding appears to be a suitable process to uniformly disperse nanotubes in the plasticized starch matrix. Interactions between plasticized starch and halloysites in the nanocomposites and microstructure modifications were monitored using Fourier transfer infrared spectroscopy, X-ray diffraction and dynamic mechanical analysis. Addition of halloysite nanotubes slightly enhances the thermal stability of starch (onset temperature of degradation delayed to higher temperatures). The tensile mechanical properties of starch are also significantly improved (up to +144% for Young's modulus and up to +29% for strength) upon addition of both modified and unmodified halloysites, interestingly without loss of ductility. Modified halloysites lead to significantly higher Young's modulus than unmodified halloysites. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Assembly of functional gold nanoparticle on silica microsphere.

    Science.gov (United States)

    Wang, Hsuan-Lan; Lee, Fu-Cheng; Tang, Tse-Yu; Zhou, Chenguang; Tsai, De-Hao

    2016-05-01

    We demonstrate a controlled synthesis of silica microsphere with the surface-decorated functional gold nanoparticles. Surface of silica microsphere was modified by 3-aminopropypltriethoxysilane and 3-aminopropyldimethylethoxysilane to generate a positive electric field, by which the gold nanoparticles with the negative charges (unconjugated, thiolated polyethylene glycol functionalized with the traceable packing density and conformation) were able to be attracted to the silica microsphere. Results show that both the molecular conjugation on gold nanoparticle and the uniformity in the amino-silanization of silica microsphere influenced the loading and the homogeneity of gold nanoparticles on silica microsphere. The 3-aminopropyldimethylethoxysilane-functionalized silica microsphere provided an uniform field to attract gold nanoparticles. Increasing the ethanol content in aminosilane solution significantly improved the homogeneity and the loading of gold nanoparticles on the surface of silica microsphere. For the gold nanoparticle, increasing the molecular mass of polyethylene glycol yielded a greater homogeneity but a lower loading on silica microsphere. Bovine serum albumin induced the desorption of gold nanoparticles from silica microsphere, where the extent of desorption was suppressed by the presence of high-molecular mass polyethylene glycol on gold nanoparticles. This work provides the fundamental understanding for the synthesis of gold nanoparticle-silica microsphere constructs useful to the applications in chemo-radioactive therapeutics. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Analysis of Biodegradation of Bioplastics Made of Cassava Starch

    Directory of Open Access Journals (Sweden)

    Nanang Eko Wahyuningtiyas

    2017-08-01

    Full Text Available Environmental pollution due to plastic waste taking too long to decompose has become a global problem. There have been numerous solutions proposed, one of which is the use of bioplastics. The use of cassava starch as the main ingredient in the manufacture of bioplastics shows great potential, since Indonesia has a diverse range of starch-producing plants. The aim of the present study is to analyse the effect of glycerol on microbial degradation. This experimental research investigated the use of cassava flour mixed with glycerol plasticizer at various concentrations (0, 2, 2.5, 3% in the synthesis of bioplastics. The aspects studied were biodegradability, moisture absorption (using ASTM D570, shelf life, and morphological properties (using a camera equipped with a macro lens and SEM. This study revealed that complete degradation could be achieved on the 9th day. The addition of a large concentration of glycerol would accelerate the microbial degradation process, increase moisture, and extend the shelf life of bioplastics in a dry place.

  17. Thermal characterization of partially hydrolyzed cassava (Manihot esculenta starch granules

    Directory of Open Access Journals (Sweden)

    Luiz Gustavo Lacerda

    2008-12-01

    Full Text Available Cassava starch, partially hydrolyzed by fungal á-amylase, was characterized using thermal analysis, light microscopy and X-ray diffraction. Thermal degradation was initiated at lower degradation temperatures after enzymatic treatment and the DSC (Differential scanning calorimetry analysis showed almost similar range of gelatinization temperature, but the enthalpies of gelatinization were quite increased for the partially hydrolyzed starch granules. The results suggested that the partial degradation of the starch granules was concentrated in the amorphous regions.Amilases fúngicas são comumente empregadas a amidos com o intuito de otimizar o rendimento de leveduras, modificar a textura de produtos panificados e prolongar a vida de prateleira do produto final. A hidrólise parcial enzimática pode auxiliar no entendimento da estrutura do amido ganular. Amido de mandioca parcialmente hidrolisado por á-amilase fúngica foi investigado utilizando-se técnicas termoanalíticas, microscopia ótica e difratometria por raios X. A degradação térmica iniciou-se a temperaturas menores após o tratamento enzimático e a análise por DSC mostrou uma próxima faixa de temperatura de gelatinização, porém, a entalpia necessária para o evento foi maior para os grânulos parcialmente hidrolisados. Os resultados sugerem que a degradação parcial do amido granular foi concentrada em regiões amorfas.

  18. Electrocatalytic activity of silver decorated ceria microspheres for the oxygen reduction reaction and their application in aluminium-air batteries.

    Science.gov (United States)

    Sun, Shanshan; Xue, Yejian; Wang, Qin; Li, Shihua; Huang, Heran; Miao, He; Liu, Zhaoping

    2017-07-11

    Nanosheet-constructing porous CeO 2 microspheres with silver nanoparticles anchored on the surface were developed as a highly efficient oxygen reduction reaction (ORR) catalyst. The aluminum-air batteries applying Ag-CeO 2 as the ORR catalyst exhibit a high output power density and low degradation rate of 345 mW cm -2 and 2.6% per 100 h, respectively.

  19. Preparation and physicochemical characteristics of polylactide microspheres of emamectin benzoate by modified solvent evaporation/extraction method.

    Science.gov (United States)

    Zhang, Shao Fei; Chen, Peng Hao; Zhang, Fei; Yang, Yan Fang; Liu, De Kun; Wu, Gang

    2013-12-18

    Emamectin benzoate is highly effective against insect pests and widely used in the world. However, its biological activity is limited because of high resistance of target insects and rapid degradation speed in fields. Preparation and physicochemical characterization of degradable microcapsules of emamectin benzoate were studied by modified solvent evaporation/extraction method using polylactide (PLA) as wall material. The influence of different compositions of the solvent in internal organic phase and external aqueous phase on diameter, span, pesticide loading, and entrapment rate of the microspheres was investigated. The results indicated that the process of solvent extraction and the formation of the microcapsules would be accelerated by adding water-miscible organic solvents such as ethyl ether, acetone, ethyl acetate, or n-butanol into internal organic phase and external aqueous phase. Accelerated formation of the microcapsules would result in entrapment rates of emamectin benzoate increased to as high as 97%. In addition, by adding ethanol into the external aqueous phase, diameters would reduce to 6.28 μm, whereas the loading efficiency of emamectin benzoate did not increase. The PLA microspheres prepared under optimum conditions were smoother and more spherical. The degradation rate in PLA microspheres of emamectin benzoate on the 10th day was 4.29 ± 0.74%, whereas the degradation rates of emamectin benzoate in methanol solution and solid technical material were 46.3 ± 2.11 and 22.7 ± 1.51%, respectively. The PLA skeleton had combined with emamectin benzoate in an amorphous or molecular state by using differential scanning calorimetry (DSC) determination. The results indicated that PLA microspheres of emamectin benzoate with high entrapment rate, loading efficiency, and physicochemical characteristics could be obtained by adding water-miscible organic solvents into the internal organic phase and external aqueous phase.

  20. Degradation of Starch–Poly(β-Hydroxybutyrate-Co-β-Hydroxyvalerate) Bioplastic in Tropical Coastal Waters

    Science.gov (United States)

    Imam, S. H.; Gordon, S. H.; Shogren, R. L.; Tosteson, T. R.; Govind, N. S.; Greene, R. V.

    1999-01-01

    Extruded bioplastic was prepared from cornstarch or poly(β-hydroxybutyrate-co-β-hydroxyvalerate) (PHBV) or blends of cornstarch and PHBV. The blended formulations contained 30 or 50% starch in the presence or absence of polyethylene oxide (PEO), which enhances adherence of starch granules to PHBV. Degradation of these formulations was monitored for 1 year at four stations in coastal water southwest of Puerto Rico. Two stations were within a mangrove stand. The other two were offshore; one of these stations was on a shallow shoulder of a reef, and the other was at a location in deeper water. Microbial enumeration at the four stations revealed considerable flux in the populations over the course of the year. However, in general, the overall population densities were 1 order of magnitude less at the deeper-water station than at the other stations. Starch degraders were 10- to 50-fold more prevalent than PHBV degraders at all of the stations. Accordingly, degradation of the bioplastic, as determined by weight loss and deterioration of tensile properties, correlated with the amount of starch present (100% starch >50% starch > 30% starch > 100% PHBV). Incorporation of PEO into blends slightly retarded the rate of degradation. The rate of loss of starch from the 100% starch samples was about 2%/day, while the rate of loss of PHBV from the 100% PHBV samples was about 0.1%/day. Biphasic weight loss was observed for the starch-PHBV blends at all of the stations. A predictive mathematical model for loss of individual polymers from a 30% starch–70% PHBV formulation was developed and experimentally validated. The model showed that PHBV degradation was delayed 50 days until more than 80% of the starch was consumed and predicted that starch and PHBV in the blend had half-lives of 19 and 158 days, respectively. Consistent with the relatively low microbial populations, bioplastic degradation at the deeper-water station exhibited an initial lag period, after which degradation

  1. A REVIEW ON BIODEGRADABLE STARCH BASED FILM

    Directory of Open Access Journals (Sweden)

    Hooman Molavi

    2015-04-01

    Full Text Available In recent years, biodegradable edible films have become very important in research related to food, due to their compatibility with the environment and their use in the food packaging industry. Various sources can be used in the production of biopolymers as biodegradable films that include polysaccharides, proteins and lipids. Among the various polysaccharides, starch due to its low price and its abundance in nature is of significant importance. Several factors affect the properties of starch films; such as the source which starch is obtained from, as well as the ratio of constituents of the starch. Starch films have advantages such as low thickness, flexibility and transparency though; there are some downsides to mention, such as the poor mechanical properties and water vapor permeability. Thus, using starch alone to produce the film will led to restrictions on its use. To improve the mechanical properties of starch films and also increases resistance against humidity, several methods can be used; including the starch modifying techniques such as cross linking of starch and combining starch with other natural polymers. Other methods such as the use of lipid in formulations of films to increase the resistance to moisture are possible, but lipids are susceptible to oxidation. Therefore, new approaches are based on the integration of different biopolymers in food packaging.

  2. Microbial production of raw starch digesting enzymes | Sun | African ...

    African Journals Online (AJOL)

    Raw starch digesting enzymes refer to enzymes that can act directly on raw starch granules below the gelatinization temperature of starch. With the view of energy-saving, a worldwide interest has been focused on raw starch digesting enzymes in recent years, especially since the oil crisis of 1973. Raw starch digesting ...

  3. Physicochemical Properties of Starch Isolated from Bracken (Pteridium aquilinim) Rhizome.

    Science.gov (United States)

    Yu, Xurun; Wang, Jin; Zhang, Jing; Wang, Leilei; Wang, Zhong; Xiong, Fei

    2015-12-01

    Bracken (Pteridium aquilinum) is an important wild plant starch resource worldwide. In this work, starch was separated from bracken rhizome, and the physicochemical properties of this starch were systematically investigated and compared with 2 other common starches, that is, starches from waxy maize and potato. There were significant differences in shape, birefringence patterns, size distribution, and amylose content between bracken and the 2 other starches. X-ray diffraction analysis revealed that bracken starch exhibited a typical C-type crystalline structure. Bracken starch presented, respectively, lower and higher relative degree of crystallinity than waxy maize and potato starches. Ordered structures in particle surface differed among these 3 starches. The swelling power tendency of bracken starch in different temperature intervals was very similar to that of potato starch. The viscosity parameters during gelatinization were the lowest in waxy maize, followed by bracken and potato starches. The contents of 3 nutritional components, that is, rapidly digestible, slowly digestible, and resistant starches in native, gelatinized, and retrograded starch from bracken rhizome presented more similarities with potato starch than waxy maize starch. These finding indicated that physicochemical properties of bracken starch showed more similarities with potato starch than waxy maize starch. © 2015 Institute of Food Technologists®

  4. EFFECT OF MICROSTRUCTURE ON THE BIOPHYSICAL DEGRADATION OF STARCH

    OpenAIRE

    PARADA SILVA, JAVIER ALEJANDRO

    2010-01-01

    La respuesta glicémica producida al consumir alimentos que contienen almidón está determinada por la tasa y extensión en que éste es digerido en el tracto digestivo. Hoy en día está ampliamente aceptado que almidones cuya respuesta glicémica es menor ayudarían a prevenir ciertas enfermedades crónicas no transmisibles como obesidad, enfermedades cardiacas, diabetes, y algunos cánceres. Desde este punto de vista, el control de los factores que afectan la digestibilidad del almidón resulta un...

  5. EFFECT OF MICROSTRUCTURE ON THE BIOPHYSICAL DEGRADATION OF STARCH

    OpenAIRE

    PARADA SILVA, JAVIER ALEJANDRO; PARADA SILVA, JAVIER ALEJANDRO

    2010-01-01

    La respuesta glicémica producida al consumir alimentos que contienen almidón está determinada por la tasa y extensión en que éste es digerido en el tracto digestivo. Hoy en día está ampliamente aceptado que almidones cuya respuesta glicémica es menor ayudarían a prevenir ciertas enfermedades crónicas no transmisibles como obesidad, enfermedades cardiacas, diabetes, y algunos cánceres. Desde este punto de vista, el control de los factores que afectan la digestibilidad del almidón resulta...

  6. Influence of non starch polysaccharide-degrading enzymes on the ...

    African Journals Online (AJOL)

    enzymes on the performance, meat yield, water intake, litter moisture and jejunal digesta viscosity of chicks fed wheat/barley based diet. A total of 195 1-d-old male broiler chicks (Ross 308) were allocated to 5 treatment groups, with 3 replicates per ...

  7. Influence of non starch polysaccharide-degrading enzymes on the ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-03-08

    Mar 8, 2010 ... A total of 195 1-d-old male broiler chicks (Ross 308) were allocated to 5 treatment groups, with 3 replicates per .... exceed all nutrient recommendations published in the Ross rear guideline. The five dietary ... profiles (according to prediction formula existing in NRC, 1994), crude protein (CP), crude fiber ...

  8. Structural biology of starch-degrading enzymes and their regulation

    DEFF Research Database (Denmark)

    Møller, Marie Sofie; Svensson, Birte

    2016-01-01

    disproportionating enzyme and a self-stabilised conformation of amylose accommodated in the active site of plant α-glucosidase. Important inhibitor complexes include a flavonol glycoside, montbretin A, binding at the active site of human pancreatic α-amylase and barley limit dextrinase inhibitor binding...

  9. Hierarchical synthesis of corrugated photocatalytic TiO2 microsphere architectures on natural pollen surfaces

    Science.gov (United States)

    Erdogan, Deniz Altunoz; Ozensoy, Emrah

    2017-05-01

    Biomaterials are challenging, yet vastly promising templates for engineering unusual inorganic materials with unprecedented surface and structural properties. In the current work, a novel biotemplate-based photocatalytic material was synthesized in the form of corrugated TiO2 microspheres by utilizing a sol-gel methodology where Ambrosia trifida (Ab, Giant ragweed) pollen was exploited as the initial biological support surface. Hierarchically synthesized TiO2 microspheres were structurally characterized in detail via SEM-EDX, Raman spectroscopy, XRD and BET techniques in order to shed light on the surface chemistry, crystal structure, chemical composition and morphology of these novel material architectures. Photocatalytic functionality of the synthesized materials was demonstrated both in gas phase as well as in liquid phase. Along these lines, air and water purification capabilities of the synthesized TiO2 microspheres were established by performing photocatalytic oxidative NOx(g) storage and Rhodamine B(aq) degradation experiments; respectively. The synthetic approach presented herein offers new opportunities to design and create sophisticated functional materials that can be used in micro reactor systems, adsorbents, drug delivery systems, catalytic processes, and sensor technologies.

  10. Optically Levitated Microspheres as a Probe for New Interactions

    Science.gov (United States)

    Rider, Alexander; Moore, David; Blakemore, Charles; Lu, Marie; Gratta, Giorgio

    2016-03-01

    We are developing novel techniques to probe new interactions at micron distances using optically levitated dielectric microspheres. Levitated microspheres are an ideal probe for short-range interactions because they are suspended using the radiation pressure at the focus of a laser beam, which means that the microspheres can be precisely manipulated and isolated from the surrounding environment at high vacuum. We have performed a search for unknown charged particles bound within the bulk of the microspheres. Currently, we are searching for the presence of a Chameleon field postulated to explain the presence of dark energy in the universe. In the future we plan to use optically levitated microspheres to search for micron length-scale gravity like interactions that could couple between a microsphere and another mass. We will present resent results from these experiments and plans for future searches for new interactions.

  11. Synthesis of mesoporous BiOBr 3D microspheres and their photodecomposition for toluene

    International Nuclear Information System (INIS)

    Feng Yinchang; Li Lei; Li Junwei; Wang Junfeng; Liu Lu

    2011-01-01

    Graphical abstract: Display Omitted Highlights: → Mesoporous bismuth oxybromide (BiOBr) microspheres assembled by nanosheets were synthesized by a simple solvothermal route. → It was reported for the first time that mesoporous BiOBr microspheres were used to degrade gas phase toluene. → The intermediates under different irradiation source were identified and the relationship between intermediates and reaction rate constant was discussed. → Fifteen kinds of intermediates were detected through GC-MS analysis, and a tentative degradation pathway was proposed. - Abstract: In this article, a facile solvothermal method was introduced to synthesize mesoporous BiOBr microspheres with Bi(NO 3 ) 3 as Bi source. The synthesized catalysts were characterized by XRD, SEM, TEM, XPS, UV-vis, TG-DTA, and N 2 -adsorption-desorption, and their photoactivity was evaluated by gaseous toluene both under UV and UV-vis irradiation with Degussa TiO 2 P 25 as reference. The prepared BiOBr catalysts were of pure tetragonal phase and its band gap energy was calculated to be about 2.64 eV. Comparing with P 25 , BiOBr showed promoted photocatalytic activity under UV-vis irradiation, during which more than 90% of toluene was eliminated after 5 h irradiation. Kinetic analysis further demonstrated the enhanced activity of BiOBr under UV-vis irradiation and the reaction rate constant k of BiOBr was nearly 2 times higher than that of P 25 . The superior activity of BiOBr under UV-vis irradiation can be attributed to its hierarchical structure and suitable band gap energy. Moreover, the reacted intermediates under different light source were identified by GC-MS. Fifteen main intermediates were identified and a tentative pathway of toluene degradation by BiOBr was proposed.

  12. New Evidences on the Process Sensitivity of Some Renewable Blends Based on Starch considering Their Melt Rheological Properties

    Directory of Open Access Journals (Sweden)

    Doina Dimonie

    2016-01-01

    Full Text Available The degradability and processability of new renewable materials based on starch and PVOH were studied using the melt flow index (MFI method by measuring the melt rheological properties which depend not only on the extrusion conditions and material formulation but also on the macromolecule characteristics which can be modified by chemical degradation. These results were correlated with other material properties like color and cross-linking degree. The obtained results show that flowing in the melted state of the studied materials is accompanied by a second process of chains chemical degradation. It was observed that, at the same level of additivation, under identical extrusion conditions, the melted blends with corn starch as main component are highly mechanically sensitive and degrade mostly by chains scission and those with PVOH as major component are highly temperature sensitive and degrade mainly by cross-linking. The obtained results show also that each PVOH-starch blend requires particular formulation and individual windows of melt processing conditions. These results are a good proof that the MFI method is a good path to study the degradability and moldability of process sensitive polymeric materials like those based on starch and PVOH.

  13. Granule integrity and starch solubility during slow, extended pasting of maize starch - the second viscosity peak

    CSIR Research Space (South Africa)

    Nelles, EM

    2003-02-01

    Full Text Available Maize starch granule integrity and starch solubilisation at specific intervals during a relatively long pasting profile-which is known to exhibit biphasic peak viscosity character-was studied by microscopy and high-performance size...

  14. Plant-crafted starches for bioplastics production

    DEFF Research Database (Denmark)

    Sagnelli, Domenico; Hebelstrup, Kim H.; Leroy, Eric

    2016-01-01

    Transgenically-produced amylose-only (AO) starch was used to manufacture bioplastic prototypes. Extruded starch samples were tested for crystal residues, elasticity, glass transition temperature, mechanical properties, molecular mass and microstructure. The AO starch granule crystallinity was both...... samples displayed Vh- and B-type crystalline structures, the B-type polymorph being the dominant one. The AO prototypes demonstrated a 6-fold higher mechanical stress at break and 2.5-fold higher strain at break compared to control starch. Dynamic mechanical analysis showed a significant increase...... of the B- and Vh-type, while the isogenic control starch was mainly A-type. The first of three endothermic transitions was attributed to gelatinization at about 60°C. The second and third peaks were identified as melting of the starch and amylose-lipid complexes, respectively. After extrusion, the AO...

  15. Application of radiation technology in starch modification

    International Nuclear Information System (INIS)

    Chen Huiyuan; Peng Zhigang; Ding Zhongmin; Lu Jiajiu

    2007-01-01

    In order to commercialize the radiation modification of starch, corn starch was irradiated with different dose of 60 Co gamma radiations. Some basic physical and chemical properties of the resulted modified starch paste were measured with emphasis on the viscosity stability and tensile strength. The results indicate that irradiation of corn starch with a dose of 4-10 kGy can decrease its viscosity to 5-14 mPa·s, and the tensile strength can meet the standard set up for textile paste. In comparison with chemical modification for starch, radiation modification is simpler in technology, more convenient in operation, more stable in modification quality, and easier to control. The mechanism of radiation modification of starch was also discussed. (authors)

  16. Potential of Starch Nanocomposites for Biomedical Applications

    Science.gov (United States)

    Zakaria, N. H.; Muhammad, N.; Abdullah, M. M. A. B.

    2017-06-01

    In recent years, the development of biodegradable materials from renewable sources based on polymeric biomaterials have grown rapidly due to increase environmental concerns and the shortage of petroleum sources. In this regard, naturally renewable polymers such as starch has shown great potential as environmental friendly materials. Besides, the unique properties of starch such as biodegradable and non-toxic, biocompatible and solubility make them useful for a various biomedical applications. Regardless of their unique properties, starch materials are known to have limitations in term of poor processability, low mechanical properties, poor long term stability and high water sensitivity. In order to overcome these limitations, the incorporation of nano size fillers into starch materials (nanocomposites) has been introduced. This review aims to give an overview about structure and characteristics of starch, modification of starch by nanocomposites and their potential for biomedical applications.

  17. FUNCIONALES PROPERTIES SAGO STARCH (Maranta arundinacea

    Directory of Open Access Journals (Sweden)

    Clemente Granados C

    2014-12-01

    Full Text Available Maranta arundinacea sago whose rhizome is used in parts of Colombian for the production of products intended for human consumption. Starch was extracted and determined the functional properties of starches presented high water capacity % CRA (162,8% for sago, compared to 226% of cassava, a high rate of absorption of lipids % I.A.L (51% for sago, compared to 82,25% of cassava starch. Gelatinization temperature is relatively low (65-75ºC at 10 minutes compared to sago starch cassava with 70-75ºC in 20 minutes, has a high percentage of amylopectin (77% for sago starch, compared with 83,3% for cassava starch is a gel so that no retrograde and from a stable paste. As it is concluded that can be used as an alternative promising in the food industry.

  18. Microsphere-Based Scaffolds Carrying Opposing Gradients of Chondroitin Sulfate and Tricalcium Phosphate

    Directory of Open Access Journals (Sweden)

    Vineet eGupta

    2015-07-01

    Full Text Available Extracellular matrix (ECM components such as chondroitin sulfate (CS and tricalcium phosphate (TCP serve as raw materials and thus spatial patterning of these raw materials may be leveraged to mimic the smooth transition of physical, chemical and mechanical properties at the bone-cartilage interface. We hypothesized that encapsulation of opposing gradients of these raw materials in high molecular weight poly(D,L-lactic-co-glycolic acid (PLGA microsphere-based scaffolds would enhance differentiation of rat bone marrow stromal cells (rBMSCs. The raw material encapsulation altered the microstructure of the microspheres and also influenced the cellular morphology that depended on the type of material encapsulated. Moreover, the mechanical properties of the raw material encapsulating microsphere-based scaffolds initially relied on the composition of the scaffolds and later on were primarily governed by the degradation of the polymer phase and newly synthesized extracellular matrix by the seeded cells. Furthermore, raw materials had a mitogenic effect on the seeded cells and led to increased glycosaminoglycan (GAG, collagen, and calcium content. Interestingly, the initial effects of raw material encapsulation on a per-cell basis might have been overshadowed by medium-regulated environment that appeared to favor osteogenesis. However, it is to be noted that in vivo, differentiation of the cells would be governed by the surrounding native environment. Thus, the results of this study demonstrated the potential of the raw materials in facilitating neo-tissue synthesis in microsphere-based scaffolds and perhaps in combination with bioactive signals, these raw materials may be able to achieve intricate cell differentiation profiles required for regenerating the osteochondral interface.

  19. Starch stabilized Pickering emulsions : Colloidal starch particles and their effects on emulsion properties

    OpenAIRE

    Saari, Hisfazilah

    2017-01-01

    Particles can be used to stabilize multi-phase systems known as Pickering emulsions. The aim of this thesis was to investigate how starch particles affect emulsion properties. Starch granules were used individually as well as in binary mixtures. To obtain a wide variety of starch properties granules were selected based on botanic variation (quinoa, oat, waxy barley, waxy maize and potato). The properties of the starch particles were furthermore changed by size fractionation by sedimentation, ...

  20. [Studies on preparation technology of microspheres of contraceptives].

    Science.gov (United States)

    Lei, Y; Lu, B

    1993-01-01

    Contraceptive poly ethylglycol-lactide (PEGL), an artificial biodegradable polymer microsphere was prepared by a solvent evaporation process using levonorgestrel (LNG) and estradiol (E2) as model drugs and PEGL as the core material. The experimental conditions were optimized, the mean volume diameter obtained being 30 microns and rate of encapsulation 75-82%. In vitro, it was found that the drug release rate decreased with decreasing drug content in the microspheres. The microspheres of the contraceptive maintained anticonception duration in mice for over 6 months, indicating that the microspheres have remarkably long acting sustained release action.

  1. Photoluminescence and lasing in whispering gallery mode glass microspherical resonators

    International Nuclear Information System (INIS)

    Ristić, D.; Berneschi, S.; Camerini, M.; Farnesi, D.; Pelli, S.; Trono, C.; Chiappini, A.; Chiasera, A.; Ferrari, M.; Lukowiak, A.; Dumeige, Y.; Féron, P.; Righini, G.C.; Soria, S.; Conti, G. Nunzi

    2016-01-01

    We report experimental results regarding the development of Er 3+ -doped glass microspherical cavities for the fabrication of compact sources at 1.55 μm. We investigate several different approaches in order to fabricate the microspheres including direct melting of Er 3+ -doped glass powders, synthesis of Er 3+ -doped monolithic microspheres by drawing Er 3+ -doped glass, and coating of silica microspheres with an Er 3+ -doped sol–gel layer. Details of the different fabrication processes are presented together with the photoluminescence characterization in free space configuration of the microspheres and of the glass precursor. We have analyzed the photoluminescence spectra of the whispering gallery modes of the microspheres excited using evanescent coupling and we demonstrate tunable laser action in a wide range of wavelengths around 1.55 μm. As much as 90 μW of laser output power was measured in Er 3+ -doped glass microspheres. - Highlights: • Different approaches in microsphere fabrication and various types of post-processing. • Trimming of photorefractive glass microsphere lasers with UV light. • Peak power record of 90 μW by pumping at 1480 nm.

  2. Preparation and characterization of immobilized lipase on magnetic hydrophobic microspheres

    DEFF Research Database (Denmark)

    Guo, Zheng; Bai, Shu; Sun, Yan

    2003-01-01

    A novel magnetic poly(vinyl acetate (VAc)–divinyl benzene (DVB)) material (8–34 μm) was synthesized by copolymerization of vinyl acetate and divinyl benzene using oleic acid-stabilized magnetic colloids as magnetic cores. The magnetic colloids and the copolymer microspheres were characterized...... with transmission and scanning electron microscopes, respectively. Magnetization of the microspheres could be described by the Langevin function. All the observations indicated that the microspheres were superparamagnetic. Magnetic sedimentation of the microspheres was achieved within 3 min, over 300 times faster...... recovered by magnetic separations....

  3. PLGA and PHBV Microsphere Formulations and Solid-State Characterization

    DEFF Research Database (Denmark)

    Yang, Chiming; Plackett, David; Needham, David

    2009-01-01

    To develop and characterize the solid-state properties of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) microspheres for the localized and controlled release of fusidic acid (FA). The effects of FA loading and polymer composition on the mean...... diameter, encapsulation efficiency and FA released from the microspheres were determined. The solid-state and phase separation properties of the microspheres were characterized using DSC, XRPD, Raman spectroscopy, SEM, laser confocal and real time recording of single microspheres formation. Above a loading...

  4. Photoluminescence and lasing in whispering gallery mode glass microspherical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Ristić, D. [Ruđer Bošković Institute, Division of Materials Physics, Laboratory for Molecular Physics, Bijenička c. 54, Zagreb (Croatia); Center of Excellence for Advanced Materials and Sensing Devices, Research unit New Functional Materials, Bijenička c. 54, Zagreb (Croatia); Berneschi, S.; Camerini, M. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Farnesi, D.; Pelli, S. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Trono, C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Chiappini, A.; Chiasera, A.; Ferrari, M. [CSMFO Group, Istituto di Fotonica e Nanotecnologie, IFN-CNR, Via alla Cascata 56/C, 38050 Povo-Trento (Italy); Lukowiak, A. [Institute of Low Temperature and Structure Research, PAS, ul. Okolna 2, Wroclaw 50-950 (Poland); Dumeige, Y.; Féron, P. [Laboratoire d' Optronique, (CNRS-UMR 6082-Foton), ENSSAT, 6 rue de Kérampont, 22300 Lannion (France); Righini, G.C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Soria, S., E-mail: s.soria@ifac.cnr.it [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Conti, G. Nunzi [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy)

    2016-02-15

    We report experimental results regarding the development of Er{sup 3+}-doped glass microspherical cavities for the fabrication of compact sources at 1.55 μm. We investigate several different approaches in order to fabricate the microspheres including direct melting of Er{sup 3+}-doped glass powders, synthesis of Er{sup 3+}-doped monolithic microspheres by drawing Er{sup 3+}-doped glass, and coating of silica microspheres with an Er{sup 3+}-doped sol–gel layer. Details of the different fabrication processes are presented together with the photoluminescence characterization in free space configuration of the microspheres and of the glass precursor. We have analyzed the photoluminescence spectra of the whispering gallery modes of the microspheres excited using evanescent coupling and we demonstrate tunable laser action in a wide range of wavelengths around 1.55 μm. As much as 90 μW of laser output power was measured in Er{sup 3+}-doped glass microspheres. - Highlights: • Different approaches in microsphere fabrication and various types of post-processing. • Trimming of photorefractive glass microsphere lasers with UV light. • Peak power record of 90 μW by pumping at 1480 nm.

  5. Synthesis of raspberry-like magnetic polystyrene microspheres

    International Nuclear Information System (INIS)

    Xu Zhizhong; Xia Ao; Wang Changchun; Yang Wuli; Fu Shoukuang

    2007-01-01

    Raspberry-like magnetic polystyrene microspheres were prepared via soap-free emulsion polymerization using 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V50) as initiator. The effect of polymerization parameters, such as initiator type, initiator content and the feeding sequence on the particle size and morphology of magnetic polystyrene microspheres, were examined. The final magnetic polystyrene microspheres were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The experimental results showed that V50 was a suitable initiator for preparation of raspberry-like magnetic polystyrene microspheres

  6. Thermal Behaviour of Nanocomposites based on Glycerol Plasticized Thermoplastic Starch and Cellulose Nanocrystallites

    Science.gov (United States)

    Kaushik, Anupama; Kaur, Ramanpreet

    2011-12-01

    The objective of this study was to study the thermal behaviour of cellulose nanocrystals/TPS based nanocomposites. Nanocrystalline cellulose was isolated from cotton linters using sonochemical method and characterized through WAXRD & TEM. These nanocrystals were then dispersed in glycerol plasticized starch in varying proportions and films were cast. The thermal degradation of thermoplastic starch/cellulose nanocrystallite nanocomposites was studied using TGA under nitrogen atmosphere. Thermal degradation was carried out for nanocomposites at a rate of 10 °C/min and at different rates under nitrogen atmosphere namely 2, 5, 10, 20 and 40 °C/min for nanocomposites containing 10% cellulose nanocrystals. Ozawa and Flynn and Kissinger methods were used to determine the apparent activation energy of these nanocomposites. The addition of cellulose nanocrystallites produced a significant effect on the activation energy for thermal degradation of the composites materials in comparison with the matrix alone. These nanocomposites are potential applicant for food packaging applications.

  7. Chemically Modified Starch; Allyl- and Epoxy-Starch Derivatives: Their Synthesis and Characterization

    NARCIS (Netherlands)

    Franssen, M.C.R.; Boeriu, C.

    2014-01-01

    Both native and modified starches, such as starch that is pregelatinized, extruded, acid-converted, cross-linked, and substituted, are widely used in industry. This chapter describes a mild two-step process for the synthesis of novel, highly reactive granular epoxy-starch derivatives. Via this

  8. Starch meets biotechnology : in planta modification of starch composition and functionalities

    NARCIS (Netherlands)

    Xu, Xuan

    2016-01-01

    Storage starch is an energy reservoir for plants and the major source of calories in the human diet. Starch is used in a broad range of industrial applications, as a cheap, abundant, renewable and biodegradable biopolymer. However, starch needs to be modified before it can fulfill the required

  9. Starch aerogel beads obtained from inclusion complexes prepared from high amylose starch and sodium palmitate

    Science.gov (United States)

    Starch aerogels are a class of low density highly porous renewable materials currently prepared from retrograded starch gels and are of interest for their good surface area, porosity, biocompatibility, and biodegradability. Recently, we have reported on starches containing amylose-fatty acid salt h...

  10. Inducing PLA/starch compatibility through butyl-etherification of waxy and high amylose starch.

    Science.gov (United States)

    Wokadala, Obiro Cuthbert; Emmambux, Naushad Mohammad; Ray, Suprakas Sinha

    2014-11-04

    In this study, waxy and high amylose starches were modified through butyl-etherification to facilitate compatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and wettability tests showed that hydrophobic butyl-etherified waxy and high amylose starches were obtained with degree of substitution values of 2.0 and 2.1, respectively. Differential scanning calorimetry, tensile testing, and scanning electron microscopy (SEM) demonstrated improved PLA/starch compatibility for both waxy and high amylose starch after butyl-etherification. The PLA/butyl-etherified waxy and high amylose starch composite films had higher tensile strength and elongation at break compared to PLA/non-butyl-etherified composite films. The morphological study using SEM showed that PLA/butyl-etherified waxy starch composites had a more homogenous microstructure compared to PLA/butyl-etherified high amylose starch composites. Thermogravimetric analysis showed that PLA/starch composite thermal stability decreased with starch butyl-etherification for both waxy and high amylose starches. This study mainly demonstrates that PLA/starch compatibility can be improved through starch butyl-etherification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. DISINTEGRATION EFFICIENCY OF SODIUM STARCH GLYCOLATES, PREPARED FROM DIFFERENT NATIVE STARCHES

    NARCIS (Netherlands)

    BOLHUIS, GK; ARENDSCHOLTE, AW; STUUT, GJ; DEVRIES, JA

    1994-01-01

    In a comparative evaluation, the disintegration efficiency of sodium starch glycolates prepared from seven different native starches (potato, maize, waxy maize, wheat, rice, sago and tapioca) were compared. All the sodium starch glycolates tested had a high swelling capacity, but the rate of water

  12. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres.

    Science.gov (United States)

    de Silva, Suresh; Mackie, Simon; Aslan, Peter; Cade, David; Delprado, Warick

    2016-12-01

    Intra-arterial brachytherapy with yttrium-90 ( 90 Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of 90 Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model. In each of six pigs, ~25-33 % of the kidney volume was embolized with 90 Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8-9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from 90 Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed. Kidneys embolized with 90 Y-radioembolization decreased in mass by 30-70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the 90 Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10 6 ) of bland microspheres. This study showed that radioembolization with 90 Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of 90 Y resin microspheres for the localized treatment of kidney tumors.

  13. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Suresh de, E-mail: suresh.desilva@unsw.edu.au [Southern Radiology Group, Radiology Department Sutherland Hospital (Australia); Mackie, Simon [Western General Hospital, Department of Urology (United Kingdom); Aslan, Peter [St George Hospital, Department of Urology (Australia); Cade, David [Sirtex Technology Pty Ltd (Australia); Delprado, Warick [Douglass Hanly Moir Pathology (Australia)

    2016-12-15

    BackgroundIntra-arterial brachytherapy with yttrium-90 ({sup 90}Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of {sup 90}Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with {sup 90}Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from {sup 90}Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with {sup 90}Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the {sup 90}Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10{sup 6}) of bland microspheres.ConclusionThis study showed that radioembolization with {sup 90}Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of {sup 90}Y resin microspheres for the localized treatment of kidney tumors.

  14. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    International Nuclear Information System (INIS)

    Silva, Suresh de; Mackie, Simon; Aslan, Peter; Cade, David; Delprado, Warick

    2016-01-01

    BackgroundIntra-arterial brachytherapy with yttrium-90 ( 90 Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of 90 Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with 90 Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from 90 Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with 90 Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the 90 Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10 6 ) of bland microspheres.ConclusionThis study showed that radioembolization with 90 Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of 90 Y resin microspheres for the localized treatment of kidney tumors.

  15. Enzymatic modification of low conversion starch products

    Energy Technology Data Exchange (ETDEWEB)

    Slominska, L.

    1989-05-01

    Recently produced low conversion starch products (maltodextrins) contain relatively low level of mono- and disaccharides such as glucose and maltose. A study on obtaining starch hydrolyzates containing significant amounts of glucose and maltose without fundamental change of their dextrose equivalent was conducted. The influence of glucogenic and maltogenic amylases (NOVO) on low conversion starch products was investigated by measurement of their sugar composition, viscosity, filterability, iodine absorbance value and turbidity. The results show different properties of novel starch hydrolyzates depending on the enzymes used.

  16. Comparison of CO(2) and bicarbonate as inorganic carbon sources for triacylglycerol and starch accumulation in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Gardner, Robert D; Lohman, Egan; Gerlach, Robin; Cooksey, Keith E; Peyton, Brent M

    2013-01-01

    Microalgae are capable of accumulating high levels of lipids and starch as carbon storage compounds. Investigation into the metabolic activities involved in the synthesis of these compounds has escalated since these compounds can be used as precursors for food and fuel. Here, we detail the results of a comprehensive analysis of Chlamydomonas reinhardtii using high or low inorganic carbon concentrations and speciation between carbon dioxide and bicarbonate, and the effects these have on inducing lipid and starch accumulation during nitrogen depletion. High concentrations of CO(2) (5%; v/v) produced the highest amount of biofuel precursors, transesterified to fatty acid methyl esters, but exhibited rapid accumulation and degradation characteristics. Low CO(2) (0.04%; v/v) caused carbon limitation and minimized triacylglycerol (TAG) and starch accumulation. High bicarbonate caused a cessation of cell cycling and accumulation of both TAG and starch that was more stable than the other experimental conditions. Starch accumulated prior to TAG and then degraded as maximum TAG was reached. This suggests carbon reallocation from starch-based to TAG-based carbon storage. Copyright © 2012 Wiley Periodicals, Inc.

  17. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  18. Microsphere Assemblies via Phosphonate Monoester Coordination Chemistry.

    Science.gov (United States)

    Bladek, Kamila J; Reid, Margaret E; Nishihara, Hirotomo; Akhtar, Farid; Gelfand, Benjamin S; Shimizu, George K H

    2018-02-01

    By complexing a bent phosphonate monoester ligand with cobalt(II), coupled with in situ ester hydrolysis, coordination microspheres (CALS=CALgary Sphere) are formed whereas the use of the phosphonic acid directly resulted in a sheet-like structure. Manipulation of the synthetic conditions gave spheres with different sizes, mechanical stabilities, and porosities. Time-dependent studies determined that the sphere formation likely occurred through the formation of a Co 2+ and ligand chain that propagates in three dimensions through different sets of interactions. The relative rates of these assembly processes versus annealing by ester hydrolysis and metal dehydration determine the growth of the microspheres. Hardness testing by nanoindentation is carried out on the spheres and sheets. Notably, no templates or capping agents are employed, the growth of the spheres is intrinsic to the ligand geometry and the coordination chemistry of cobalt(II) and the phosphonate monoester. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Sputter coating of microspherical substrates by levitation

    Science.gov (United States)

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  20. STRUCTURING OF DIAMOND FILMS USING MICROSPHERE LITHOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mária Domonkos

    2014-10-01

    Full Text Available In this study, the structuring of micro- and nanocrystalline diamond thin films is demonstrated. The structuring of the diamond films is performed using the technique of microsphere lithography followed by reactive ion etching. Specifically, this paper presents a four-step fabrication process: diamond deposition (microwave plasma assisted chemical vapor deposition, mask preparation (by the standard Langmuir-Blodgett method, mask modification and diamond etching. A self-assembled monolayer of monodisperse polystyrene (PS microspheres with close-packed ordering is used as the primary template. Then the PS microspheres and the diamond films are processed in capacitively coupled radiofrequency plasma  using different plasma chemistries. This fabrication method illustrates the preparation of large arrays of periodic and homogeneous hillock-like structures. The surface morphology of processed diamond films is characterized by scanning electron microscopy and atomic force microscope. The potential applications of such diamond structures in various fields of nanotechnology are also briefly discussed.

  1. Yttrium-90 microsphere induced gastrointestinal tract ulceration

    Directory of Open Access Journals (Sweden)

    Rikabi Ali A

    2008-09-01

    Full Text Available Abstract Background Radiomicrosphere therapy (RT utilizing yttrium-90 (90Y microspheres has been shown to be an effective regional treatment for primary and secondary hepatic malignancies. We sought to determine a large academic institution's experience regarding the extent and frequency of gastrointestinal complications. Methods Between 2004 and 2007, 27 patients underwent RT for primary or secondary hepatic malignancies. Charts were subsequently reviewed to determine the incidence and severity of GI ulceration. Results Three patients presented with gastrointestinal bleeding and underwent upper endoscopy. Review of the pretreatment angiograms showed normal vascular anatomy in one patient, sclerosed hepatic vasculature in a patient who had undergone prior chemoembolization in a second, and an aberrant left hepatic artery in a third. None had undergone prophylactic gastroduodenal artery embolization. Endoscopic findings included erythema, mucosal erosions, and large gastric ulcers. Microspheres were visible on endoscopic biopsy. In two patients, gastric ulcers were persistent at the time of repeat endoscopy 1–4 months later despite proton pump inhibitor therapy. One elderly patient who refused surgical intervention died from recurrent hemorrhage. Conclusion Gastrointestinal ulceration is a known yet rarely reported complication of 90Y microsphere embolization with potentially life-threatening consequences. Once diagnosed, refractory ulcers should be considered for aggressive surgical management.

  2. Adsorption behavior of protein onto siloxane microspheres

    International Nuclear Information System (INIS)

    Liu Bailing; Cao Shunsheng; Deng Xiaobo; Li Songjun; Luo Rong

    2006-01-01

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption

  3. Glass microspheres covering film: first field evaluations

    International Nuclear Information System (INIS)

    Magnani, G.; Filippi, F.

    2006-01-01

    A trial was carried out to evaluate, in the North-Centre of Italy, the behaviour in field of a new plastic covering film, prepared with the inclusion of empty glass microspheres (Solex). The trial was conducted on tomato (Lycopersicon esculentum L.) and eggplant (Solanum melongena L.). The new film was compared to a covering film with the same optical (diffuse light) and constitutional (co-extruded three layers EVA-WPE) characteristics. Since the first results, the innovative film showed a better behaviour than the control one. It presented light and thermal conditions (lower temperature during the day and slightly higher temperature in the night, compared to the control film) that allowed a better growth and yield than the control film. The growth analysis of tomato showed that plants grown under glass microsphere film had an higher growth rate (dry weight/days) and thickness of leaves compared to the control one. The yield of tomato and eggplant presented an increase in plants cultivated under the innovative film, especially for number and weight of fruits. The commercial quality did not show any differences between the films, except for the flesh hardness of tomato: this could be explained with the fact that the glass microspheres film provides environmental conditions avoiding plant stress during some stages of its cycle [it

  4. DSC studies of retrogradation and amylose-lipid transition taking place in gamma-irradiated wheat starch

    International Nuclear Information System (INIS)

    Ciesla, K.; Gluszewski, W.; Eliasson, A.C.

    2006-01-01

    It has been already shown that degradation resulting from gamma irradiation induces a decrease in order of starch granules and influences gelatinisation taking place during heating of starch and flour suspensions. In presented paper, DSC (differential scanning calorimetry) studies were carried out for wheat starch, non-irradiated and irradiated using doses in the range from 5 to 30 kGy. The influence of the conditions applied during DSC measurements on the possibility to observe differences between the amylose-lipid complex transition and retrogradation taking place in the non-irradiated and particularly irradiated starch samples was checked. The better differentiation between the amylose-lipid complex transition taking place in particular samples accompanied by the better reproducity were obtained in the case of dense suspensions as compared to the watery suspensions as well as during the first analysis performed for the recrystallised gels

  5. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  6. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Nobrega

    2012-01-01

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  7. Evaluation of Colocasia esculenta Starch as an Alternative Tablet Excipient to Maize Starch: Assessment by Preformulation and Formulation Studies

    OpenAIRE

    Kusuma. R; Venkat Reddy. P; Samba Shiva Rao. A

    2015-01-01

    Starch isolated from Colocasia esculenta plant was studied as an alternative pharmaceutical excipient to maize and potato starch. The Colocasia esculenta starch has been evaluated by series of tests as mentioned in Indian Pharmacopoeia before being used for evaluation. It was tested along with maize and potato starch as an alternative excipient by performing battery of preformulation and formulation tests. The results obtained for Colocasia esculenta starch was comparable with maize starch an...

  8. Facile synthesis of monodisperse polymer/SiO2/polymer/TiO2 tetra-layer microspheres and the corresponding double-walled hollow SiO2/TiO2 microspheres.

    Science.gov (United States)

    Zhang, Han; Zhang, Xu; Yang, Xinlin

    2010-08-15

    Monodisperse tetra-layer poly(ethyleneglycol dimethacrylate-co-methacrylic acid) (P(EGDMA-co-MAA))/SiO(2)/P(EGDMA-co-MAA)/TiO(2) tetra-layer microspheres were facilely synthesized by the combination of the distillation precipitation polymerization for the preparation of P(EGDMA-co-MAA) layers and the controlled sol-gel hydrolysis of inorganic precursors for the formation of silica (SiO(2)) and titania (TiO(2)) layers. The thickness of the outer titania shell-layer was well-controlled via altering the feed of titanium tetrabutoxide (TBOT) during the sol-gel hydrolysis, while the size of polymeric layers were facilely controlled via a multi-step addition of ethyleneglycol dimethacrylate (EGDMA) crosslinker and methacrylic acid (MAA) monomer during the polymerization. The corresponding double-walled hollow inorganic microspheres containing SiO(2) inner shell and TiO(2) outer shell with various thickness were obtained after the selective removal of P(EGDMA-co-MAA) components via the calcination of the tetra-layer polymer/SiO(2)/polymer/TiO(2) microspheres under 550 degrees C for 4 h in air. The structure and morphology of the resultant microspheres were characterized by transmission electron microscopy (TEM), X-ray diffractometer (XRD), X-ray photoelectron microscopy (XPS), and thermogravimetric analysis (TGA). Further, the photocatalytic properties of the resultant double-walled hollow SiO(2)/TiO(2) microspheres were studied by photocatalytic degradation of methyl orange (MO) with ultraviolet (UV) irradiation of a 500 W high-pressure mercury lamp. Copyright 2010 Elsevier Inc. All rights reserved.

  9. Characterisation of corn starch-based films reinforced with taro starch nanoparticles.

    Science.gov (United States)

    Dai, Lei; Qiu, Chao; Xiong, Liu; Sun, Qingjie

    2015-05-01

    Taro starch nanoparticles (TSNPs) obtained by hydrolysis with pullulanase and the recrystallisation of gelatinised starch were used as reinforcing agents in corn starch films. The influence of TSNPs contents (0.5-15%) on the physical, mechanical, thermal, and structural properties of starch films was investigated. An increase in the concentration of TSNPs led to a significant decrease in the water vapour permeability (WVP) of films. The addition of TSNPs increased the tensile strength (TS) of films from 1.11 MPa to 2.87 MPa. Compared with pure starch films, the surfaces of nanocomposite films became uneven. The onset temperature (To) and melting temperature (Tm) of films containing TSNPs were higher than those of pure starch films. The addition of TSNPs improved the thermal stability of starch films. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. A titration approach to identify the capacity for starch digestion in milk-fed calves.

    Science.gov (United States)

    Gilbert, M S; van den Borne, J J G C; Berends, H; Pantophlet, A J; Schols, H A; Gerrits, W J J

    2015-02-01

    Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to determine which enzyme limits starch digestion and to assess the maximum capacity for starch digestion in milk-fed calves. A within-animal titration study was performed, where lactose was exchanged stepwise for one of four starch products (SP). The four corn-based SP differed in size and branching, therefore requiring different ratios of starch-degrading enzymes for their complete hydrolysis to glucose: gelatinised starch (α-amylase and (iso)maltase); maltodextrin ((iso)maltase and α-amylase); maltodextrin with α-1,6-branching (isomaltase, maltase and α-amylase) and maltose (maltase). When exceeding the animal's capacity to enzymatically hydrolyse starch, fermentation occurs, leading to a reduced faecal dry matter (DM) content and pH. Forty calves (13 weeks of age) were assigned to either a lactose control diet or one of four titration strategies (n=8 per treatment), each testing the stepwise exchange of lactose for one SP. Dietary inclusion of each SP was increased weekly by 3% at the expense of lactose and faecal samples were collected from the rectum weekly to determine DM content and pH. The increase in SP inclusion was stopped when faecal DM content dropped below 10.6% (i.e. 75% of the average initial faecal DM content) for 3 consecutive weeks. For control calves, faecal DM content and pH did not change over time. For 87% of the SP-fed calves, faecal DM and pH decreased already at low inclusion levels, and linear regression provided a better fit of the data (faecal DM content or pH v. time) than non-linear regression. For all SP treatments, faecal DM content and pH decreased in time (Pdigestion and that fermentation may contribute substantially to total tract starch

  11. Starch and cellulose nanocrystals together into thermoplastic starch bionanocomposites.

    Science.gov (United States)

    González, Kizkitza; Retegi, Aloña; González, Alba; Eceiza, Arantxa; Gabilondo, Nagore

    2015-03-06

    In the present work, thermoplastic maize starch based bionanocomposites were prepared as transparent films, plasticized with 35% of glycerol and reinforced with both waxy starch (WSNC) and cellulose nanocrystals (CNC), previously extracted by acidic hydrolysis. The influence of the nanofiller content was evaluated at 1 wt.%, 2.5 wt.% and 5 wt.% of WSNC. The effect of adding the two different nanoparticles at 1 wt.% was also investigated. As determined by tensile measurements, mechanical properties were improved at any composition of WSNC. Water vapour permeance values maintained constant, whereas barrier properties to oxygen reduced in a 70%, indicating the effectiveness of hydrogen bonding at the interphase. The use of CNC or CNC and WSNC upgraded mechanical results, but no significant differences in barrier properties were obtained. A homogeneous distribution of the nanofillers was demonstrated by atomic force microscopy, and a shift of the two relaxation peaks to higher temperatures was detected by dynamic mechanical analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Utilization of a Biodegradable Mulch Sheet Produced from Poly(Lactic Acid/Ecoflex®/Modified Starch in Mandarin Orange Groves

    Directory of Open Access Journals (Sweden)

    Yasukatsu Maeda

    2009-08-01

    Full Text Available We have developed a mulch sheet made by inflation molding of PLA, Ecoflex® and modified starch, which all have different biodegradabilities. A field test of use as an agricultural mulch sheet for mandarin oranges was carried out over two years. The mechanical properties of the mulch sheet were weakened with time during the field test, but the quality of the mandarin oranges increased, a result of the controlled degradation of the sheet. The most degradable modified starch degraded first, allowing control of the moisture on the soil. Accelerator mass spectroscopy was used for evaluation of the biomass carbon ratio. The biomass carbon ratio decreased by degradation of the biobased materials, PLA and modified starch in the mulch sheet.

  13. Lima Bean Starch-Based Hydrogels

    African Journals Online (AJOL)

    Oladebeyes

    ABSTRACT. Hydrogels were prepared by crosslinking native lima bean starch and polyvinyl alcohol. (PVA) with glutaraldehyde (GA) at varying proportions in an acidic medium. The native starch (N-LBS) and hydrogels (L-GA (low glutaraldehyde) and H-GA (high glutaraldehyde)) were examined for their water absorption ...

  14. The Acetylation of Starch by Reactive Extrusion

    NARCIS (Netherlands)

    Graaf, Robbert A. de; Broekroelofs, Annet; Janssen, Léon P.B.M.

    1998-01-01

    Potato starch has been acetylated in a counter rotating twin screw extruder using vinylacetate and sodium hydroxide. The desired starch acetylation reaction is accompanied by an undesired parallel base catalysed hydrolysis reaction of vinylacetate and a consecutive hydrolysis reaction of the

  15. Recrystallization of amylopectin in concentrated starch gels

    NARCIS (Netherlands)

    Keetels, CJAM; Oostergetel, GT; vanVliet, T

    The relation between the recrystallization of amylopectin and the increase in stiffness of starch gels during storage was studied by various techniques. From transmission electron microscopy it was concluded that the size of the crystalline domains in retrograded 30% w/w potato starch gels was about

  16. Wheat starch digestion rate affects broiler performance

    NARCIS (Netherlands)

    Gutierrez del Alamo Oms, A.; Verstegen, M.W.A.; Hartog, den L.A.; Perez de Ayala, P.; Villamide, M.J.

    2009-01-01

    Two experiments were conducted to determine the differences in starch digestion rate (KDS) among wheats from different cultivars and origins and to verify if chickens would benefit from a certain digestion rate of starch. In the first experiment, 192 chickens (21 d) were assigned to 4 diets

  17. Physicochemical properties of etherified maize starches

    NARCIS (Netherlands)

    Huijbrechts, A.M.L.; Desse, M.; Budtova, T.; Franssen, M.C.R.; Visser, G.M.; Boeriu, C.G.; Sudhölter, E.J.R.

    2008-01-01

    The changes in starch properties due to etherification with allyl glycidyl ether (AGE) have been investigated. After etherification of three different starches (containing 0.9%, 27% and 70% amylose), no appreciable differences in granular appearance were observed, but the granule crystallinity of

  18. Properties of corn starch subjected hydrothermal modification

    Science.gov (United States)

    Gryszkin, Artur; Zięba, Tomasz; Kapelko-Żeberska, Małgorzata

    2017-01-01

    The objective of this study was to determine the effect of heating a water dispersion of corn starch to various temperatures, followed by its freezing and defrosting, on selected properties of re-formed starch pastes. A suspension of starch was heated to various temperatures ranging from 59 to 94°C, and afterwards frozen and defrosted. The differential scanning calorimetry (Mettler Toledo, 822E) thermal characteristics of starch pre-heated to temperatures not inducing complete pasting revealed transitions of: (I) retrograded amylopectin, (II) non-pasted starch, (III) amylose-lipid complexes, (IV) retrograded amylose, and (V) highly thermostable starch structures. The application of higher temperatures during heating caused disappearance of transitions II and V. The increase of pre-heating temperature induced firstly a decrease and then stabilization of the swelling power as well as a successive decrease in starch solubility. Pastes pre-heated to temperatures over 79°C contained large macroparticles that were increasing viscosity of the re-formed starch paste (their size was positively correlated with viscosity value).

  19. Basic fibroblast growth factor eluting microspheres enhance distraction enterogenesis.

    Science.gov (United States)

    Rouch, Joshua D; Scott, Andrew; Jabaji, Ziyad B; Chiang, Elvin; Wu, Benjamin M; Lee, Steven L; Shekherdimian, Shant; Dunn, James C Y

    2016-06-01

    The purpose of this study was to determine if distraction enterogenesis using self-expanding polycaprolactone (PCL) springs is a potential therapy for short bowel syndrome. Sustained release basic fibroblast growth factor (bFGF) microspheres have been shown to induce angiogenesis and intestinal regeneration in tissue engineered scaffolds. We hypothesized that the provision of bFGF-loaded microspheres would increase angiogenesis and thereby enhance the process of enterogenesis. A 10-mm segment of rodent jejunum was isolated and an encapsulated PCL spring inserted. Blank or bFGF-loaded microspheres were delivered to the segment. After 4weeks, jejunal segments were assessed for lengthening, morphology, quantification of blood vessels, and ganglia. Lengthened intestinal segments receiving bFGF microspheres demonstrated significantly increased microvascular density compared to those with blank microspheres. There were also significantly more submucosal and myenteric ganglia in the segments that received bFGF microspheres. Segments achieved similar lengthening and final muscular thickness in both blank and bFGF groups, but the bFGF microsphere caused a significant increase in luminal diameter of the jejunal segment. Sustained release bFGF microspheres enhanced distraction enterogenesis through improved vascularity. The synergy of growth factors such as bFGF with distraction enterogenesis may yield improved results for the future treatment of patients with short bowel syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Development and evaluation of floating microspheres of curcumin in ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence and to study their effect on alloxan-induced diabetic rats. Methods: Floating microsphere were prepared by emulsion-solvent diffusion method, using hydroxylpropyl methylcellulose, chitosan and Eudragit S 100 polymer in ...

  1. Development and Evaluation of Floating Microspheres of Curcumin ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence time and increased drug bioavailability. Methods: Floating microsphere were prepared by emulsion solvent diffusion method, using hydroxylpropyl methylcellulose (HPMC), ethyl cellulose (EC), Eudragit S 100 polymer in ...

  2. Study of the element distribution into the Yttrium glass microspheres

    International Nuclear Information System (INIS)

    Garibov, A.A.; Ghahramani, M.R.; Agayev, T.N.

    2010-01-01

    Full text : Yttrium-90 microspheres administered via the hepatic artery has been used for the treatment of unresectable primary or metastatic cancer in the liver. Y-90 is a pure β-emitter and emits β-particles to decay to stable Zr-89 having peak energy of 2.28 MeV and an average energy of about 0.94 MeV. The dosimetery of low-energy β-sources is inherently complicated due to the sharp dose gradients and the limited range in tissue of the β-particles. The distribution of elements within the microspheres can be effective in the dosimetery. So in this study there was a full focus on the theme of distribution of elements into the microspheres. The quantitative analysis of the microstructure of microspheres is able, by the use of SEM mapping where the topographical analysis of microspheres cross sections is given. There has been shown the EDS maps of Azar sphere (yttrium aluminum silicate) microspheres. The EDS map indicated the distribution of the Y, Si, O, and Al elements into the microspheres at cross section. SEM/EDS line scan techniques was employed for determination of the elemental redistribution across the cross section microspheres for silicon, yttrium, aluminum and oxygen element. There is also a line scan with SEM-EDX was shown along the cross section of Azar sphere sample. The results of the scan showing the variations of concentrations of Si, Y, O and Al are shown in this article.

  3. Development and Evaluation of Floating Microspheres of Curcumin

    African Journals Online (AJOL)

    The shape and surface morphology of the microspheres were characterised by optical and scanning electron microscopy. Result: The floating microspheres showed particle size, buoyancy, drug entrapment efficiency and yield in the ranges of 251 - 387 µm, 74.6 - 90.6 %, and 72.6 - 83.5 %, and 45.5 - 82.0 %, respectively.

  4. Fabrication of polystyrene hollow microspheres as laser fusion ...

    Indian Academy of Sciences (India)

    Inertial confinement fusion, frequently referred to as ICF, inertial fusion, or laser fusion, is a means of producing energy by imploding small hollow microspheres containing thermonuclear fusion fuel. Polymer microspheres, which are used as fuel containers, can be produced by solution-based micro-encapsulation technique ...

  5. Studies of the pulmonary circulation with radioactive microspheres

    International Nuclear Information System (INIS)

    Wagner, H.N. Jr.; James, A.E. Jr.

    1972-01-01

    The use of 99 /sup m/Tc-albumin microspheres to assess the pulmonary circulation has important clinical utility. Particle distribution of injected microspheres accurately reflects regional pulmonary distribution. The value of this diagnostic technique in patients with pulmonary edema, lung neoplasms, and congenital cardiac malformations is emphasized. (U.S.)

  6. Formulation and Optimization of Celecoxib-Loaded Microspheres ...

    African Journals Online (AJOL)

    Purpose: To employ response surface methodology (RSM) for statistical optimization of formulation factors in the preparation of celecoxib-loaded microspheres. Methods: Celecoxib microspheres were prepared by solvent evaporation method. Biodegradable/biocompatible polymers, Eudragit L-100 and polyvinyl ...

  7. Preparation of magnetite-dextran microspheres by ultrasonication

    Energy Technology Data Exchange (ETDEWEB)

    Xia Zefeng [Tongji Medical College, Huazhong University of Science and Technology, Laparoscopy Centre, Xiehe Hospital, 1227 Jiefang Road, Wuhan, Hubei 430022 (China)]. E-mail: xiazefeng@sina.com; Wang Guobin [Tongji Medical College, Huazhong University of Science and Technology, Laparoscopy Centre, Xiehe Hospital, 1227 Jiefang Road, Wuhan, Hubei 430022 (China); Tao Kaixiong [Tongji Medical College, Huazhong University of Science and Technology, Laparoscopy Centre, Xiehe Hospital, 1227 Jiefang Road, Wuhan, Hubei 430022 (China); Li Jianxing [Department of Biomedical Engineering, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

    2005-05-15

    An improved method of preparing magnetite-dextran microspheres by ultrasonication is proposed. Several parameters were evaluated and the characteristics of the microspheres investigated by scanning electron microscope (SEM), atomic force microscope (AFM), particle size analyzer and magnetometer. The results show that the initial Fe/dextran ratio is the most effective parameter for both the size and the magnetic properties.

  8. Pectin/zein microspheres as a sustained drug delivery system

    Science.gov (United States)

    A series of microspheres were prepared from pectins and corn proteins from various sources in the presence of the divalent ions calcium or zinc. The results showed that the yield of microsphere and the efficiency of drug incorporation were dependent on the type and ratio of biopolymers, the size of ...

  9. The clearance of albumin microspheres from an intramuscular injection site

    International Nuclear Information System (INIS)

    Mills, S.N.; Davis, S.S.; Frier, M.; Hardy, J.G.; Wilson, C.G.

    1982-01-01

    Human serum albumin microspheres of three different diameters were radiolabelled with indium-111, and a suspension injected into rabbit thigh muscle. Clearance from the intramuscular site was monitored for 2 weeks using gamma scintigraphy. The clearance rates were compared with the injection site clearance of non-biodegradable polystyrene microspheres. (U.K.)

  10. Maize starch biphasic pasting curves

    CSIR Research Space (South Africa)

    Nelles, EM

    2000-05-01

    Full Text Available -susceptible starch. These least 14 water molecules to one anhydrous glucoseproducts may contribute directly to human nu- unit3,4 or enough water so that its addition does not lower the temperature of gelatinisation3,5). Evi- dence for the loss of molecular order... includes: irreversible granule swelling, loss of birefringence, : RVA=Rapid Visco Analyser. loss of crystallinity, viscosity development andCorresponding author: E. M. Nelles. Tel: 27 12 841 2221; Fax: 27 12 841 2386; E-mail: enelles...

  11. Characterization and characteristics of degradable polymer sacks

    International Nuclear Information System (INIS)

    Davis, Georgina

    2003-01-01

    This paper reviews the categories and characteristics of degradable polymers used to manufacture sacks for the collection and subsequent treatment of organic wastes from householders. The characteristics of polyethylene (PE) and starch-based sacks were examined using a number of different methods, including scanning electron microscopy (SEM), chemical analysis and mechanical strength testing of the sacks during their use. The analyses revealed that the characteristics of the PE and starch-based sacks were very different. Photomicrographs indicated that the surface of the PE sack was much smoother than the surface of the starch-based sacks. Polyethylene sacks exhibited a greater mechanical strength, both in the unused state and over time during householder use. The severe loss of mechanical strength during use of the starch-based sacks indicated that only thicker gauge sacks were suitable for the fortnightly kerbside collection of biodegradable municipal waste (BMW). Chemical analysis of two different PE sacks indicated that transition metals and other elements were commonly incorporated into the PE structure in order to facilitate increased polymer degradation

  12. Probing Au nanoparticle uptake by enzyme following the digestion of a starch-Au-nanoparticle composite.

    Science.gov (United States)

    Deka, Jashmini; Paul, Anumita; Ramesh, A; Chattopadhyay, Arun

    2008-09-16

    In this letter, we report on the digestion of starch, when present as a composite with Au nanoparticles (NPs), by alpha-amylase. It has been observed that the rate of digestion of free starch and that in the composite were identical. Also, the well-established iodine test could be carried out to investigate the kinetics in the presence of Au NPs. The investigations revealed that following the digestion of starch in the composite the NPs were released and subsequently attached to the enzyme only and not to the degraded products of starch. Also, the enzyme attached to NPs, following digestion, retained its catalytic activity. The particle sizes of the NPs were not affected in the process because no agglomeration was observed. Experimental observations indicated the possibility of oriented attachment of alpha-amylase to the NPs in comparison to amyloglucosidase, another digestive enzyme. Finally, we observed a change in the surface plasmon resonance (SPR) of the NPs following the digestion of starch in the composite, and thus we could demonstrate that the SPR of the NPs could be used as a direct probe for monitoring the digestion of the composite by the enzyme.

  13. Evidence against sink limitation by the sucrose-to-starch route in potato plants expressing fructosyltransferases.

    Science.gov (United States)

    Zuther, Ellen; Hoermiller, Imke I; Heyer, Arnd G

    2011-10-01

    To investigate whether the route from sucrose to starch limits sink strength of potato tubers, we established an additional storage carbohydrate pool and analyzed allocation of imported assimilates to the different pools. Tuber specific expression of the fructan biosynthetic enzymes of globe artichoke resulted in accumulation of fructans to about 5% of the starch level, but did not increase tuber dry weight per plant. While partial repression of starch synthesis caused yield reduction in wild-type plants, it stimulated fructan accumulation, and yield losses were ameliorated in tubers expressing fructosyltransferases. However, a nearly complete block of the starch pathway by inhibition of sucrose synthase could not be compensated by the fructan pathway. Although fructan concentrations rose, yield reduction was even enhanced, probably because of a futile cycle of fructan synthesis and degradation by invertase, which is induced when sucrose synthase is knocked out. The data do not support a limitation of sink strength by enzyme activities of the starch pathway but point to an energy limitation of storage carbohydrate formation in potato tubers. Copyright © Physiologia Plantarum 2011.

  14. Effect of the incorporation of antimicrobial/antioxidant proteins on the properties of potato starch films.

    Science.gov (United States)

    Moreno, Olga; Atarés, Lorena; Chiralt, Amparo

    2015-11-20

    Glycerol plasticized potato starch films containing bioactive proteins (lactoferrin (LF) and/or lysozyme (LZ), at 0.1 and 0.2 ratio with respect to starch) were obtained by casting method and characterized as to their microstructural, thermal and physical (water content, mechanical, water and oxygen barrier, optical) properties. The bioactive properties, named antioxidant and antimicrobial, of the proteins and the films were also characterized. The incorporation of proteins affected the structural and physical properties of potato starch films, while modifying their thermal behavior and increasing the glass transition temperature. Both proteins showed a certain degree of compatibility with starch chains through the bond formations (increase in Tg), while a part is separated and migrates to the film surface. Their incorporation, especially that of lactoferrin, greatly increased the film's brittleness, regardless of the films water content, although they enhance the water vapor and oxygen barrier properties, whatever the age of the film. Protein also reduced the film's transparency and gloss, while lactoferrin induced color changes. The thermal degradation of blend films and isolated proteins occurred at temperatures of over 250°C, which means that blend starch films can be thermoprocessed, according to their thermoplastic properties and following the usual practices of the plastics industries. A synergistic antimicrobial action against Escherichia coli and coliforms was observed when both LZ and LF were simultaneously applied. Both of these exhibited antioxidant capacity. Copyright © 2015. Published by Elsevier Ltd.

  15. Tailoring the structure and properties of amorphous starch blending and EB-radiation processing

    International Nuclear Information System (INIS)

    Khandal, D.; Bliard, C.; Coqueret, X.; Mikus, P.Y.; Dole, P.; Baumberger, S.

    2011-01-01

    Complete text of publication follows. Starch can be used alone and in combination with other compounds to make biodegradable articles from renewable resources. Lignins and their derivatives are good candidates for limiting the water sensitivity of starch-based materials, but they exhibit poor compatibility in blends with polysaccharides. Electron beam (EB) processing is proposed as an efficient method for inducing covalent linkages between the two constituents. Compared to unirradiated starting materials, the surface and bulk properties of EB-irradiated starch - lignin blends submitted to EB irradiation showed an interesting reduction in hydrophilicity. Radiation induced grafting of lignin models onto starch was shown to impede long-term retrogradation, with limited loss of mechanical properties. The reactivity under radiation of model blends was examined by several analytical methods. Maldi-T of mass spectrometry allowed us to propose reasonable free radical mechanisms that account for the grafting of various benzyl and cinnamyl alcohols onto maltodextrins. The presence of cinnamyl derivatives was found not only to limit degradation, but also modify the properties of the formulations (improved hydrophobicity, mechanical properties). Size exclusion chromatography and gel fraction measurements confirmed unambiguously the attachment of UV-absorbing chromophores onto the maltodextrin main chain. The combination of the obtained results demonstrates the possibility of altering in a favourable way the tensile properties of plasticized starch by applying high energy radiation to properly formulated blends including aromatic compounds like cinnamyl alcohol.

  16. Thermal Characterization of Modified Tacca Leontopetaloides Starch and Natural Rubber Based Thermoplastic Elastomer

    International Nuclear Information System (INIS)

    Ainatul Mardhiah Mohd Amin; Nur Shahidah Ab Aziz; Nurul Shuhada Mohd Makhtar; Miradatul Najwa Mohd Rodhi; Suhaila Mohd Sauid

    2014-01-01

    The purpose of this study is to identify the potential of Tacca leontopetaloides starch as bio-based thermoplastic elastomers, TPEs. Starch based polymer had been recognized to have highly potential in replace existing source of conventional elastomeric polymer. The modification process of blending starch with natural rubber, plasticizers, additives, and filler contribute to the enhancement and improvement for the properties of starch in order to produce biopolymers by approaching the properties of TPEs. Thermal properties of starch based thermoplastic was studied to evaluate the decomposition and degradation of the samples by using Thermogravimetric Analysis, TGA while the properties of endothermic reactions of the samples were thermally analyzed via Differential Scanning Calorimetry, DSC. From the analysis, it was found that the thermal properties of samples were revealed by recognizing GM-2 (green materials, GM) has high thermal resistance towards high temperature up to 480.06 degree Celsius with higher amount of residue which is 4.97 mg compared to other samples. This indicates GM-2 comprises of superior combination of ratio between natural rubbers and glycerol (plasticizer) in purpose of approaching the properties of Thermoplastic Elastomers, TPEs. (author)

  17. Glucan, Water Dikinase Activity Stimulates Breakdown of Starch Granules by Plastidial β-Amylases1[W][OA

    Science.gov (United States)

    Edner, Christoph; Li, Jing; Albrecht, Tanja; Mahlow, Sebastian; Hejazi, Mahdi; Hussain, Hasnain; Kaplan, Fatma; Guy, Charles; Smith, Steven M.; Steup, Martin; Ritte, Gerhard

    2007-01-01

    Glucan phosphorylating enzymes are required for normal mobilization of starch in leaves of Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum), but mechanisms underlying this dependency are unknown. Using two different activity assays, we aimed to identify starch degrading enzymes from Arabidopsis, whose activity is affected by glucan phosphorylation. Breakdown of granular starch by a protein fraction purified from leaf extracts increased approximately 2-fold if the granules were simultaneously phosphorylated by recombinant potato glucan, water dikinase (GWD). Using matrix-assisted laser-desorption ionization mass spectrometry several putative starch-related enzymes were identified in this fraction, among them β-AMYLASE1 (BAM1; At3g23920) and ISOAMYLASE3 (ISA3; At4g09020). Experiments using purified recombinant enzymes showed that BAM1 activity with granules similarly increased under conditions of simultaneous starch phosphorylation. Purified recombinant potato ISA3 (StISA3) did not attack the granular starch significantly with or without glucan phosphorylation. However, starch breakdown by a mixture of BAM1 and StISA3 was 2 times higher than that by BAM1 alone and was further enhanced in the presence of GWD and ATP. Similar to BAM1, maltose release from granular starch by purified recombinant BAM3 (At4g17090), another plastid-localized β-amylase isoform, increased 2- to 3-fold if the granules were simultaneously phosphorylated by GWD. BAM activity in turn strongly stimulated the GWD-catalyzed phosphorylation. The interdependence between the activities of GWD and BAMs offers an explanation for the severe starch excess phenotype of GWD-deficient mutants. PMID:17631522

  18. Optimization of sustained release aceclofenac microspheres using response surface methodology

    International Nuclear Information System (INIS)

    Deshmukh, Rameshwar K.; Naik, Jitendra B.

    2015-01-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14 ± 0.015% to 85.34 ± 0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12 h. The optimized microspheres formulation showed E.E. of 84.87 ± 0.005 with small error value (1.39). The low magnitudes of error and the significant value of R 2 in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. - Highlights: • Aceclofenac microspheres were

  19. Optimization of sustained release aceclofenac microspheres using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Rameshwar K.; Naik, Jitendra B., E-mail: jitunaik@gmail.com

    2015-03-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14 ± 0.015% to 85.34 ± 0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12 h. The optimized microspheres formulation showed E.E. of 84.87 ± 0.005 with small error value (1.39). The low magnitudes of error and the significant value of R{sup 2} in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. - Highlights: • Aceclofenac microspheres

  20. Super-Resolution Real Imaging in Microsphere-Assisted Microscopy.

    Directory of Open Access Journals (Sweden)

    Hok Sum Sam Lai

    Full Text Available Microsphere-assisted microscopy has received a lot of attention recently due to its simplicity and its capability to surpass the diffraction limit. However, to date, sub-diffraction-limit features have only been observed in virtual images formed through the microspheres. We show that it is possible to form real, super-resolution images using high-refractive index microspheres. Also, we report on how changes to a microsphere's refractive index and size affect image formation and planes. The relationship between the focus position and the additional magnification factor is also investigated using experimental and theoretical methods. We demonstrate that such a real imaging mode, combined with the use of larger microspheres, can enlarge sub-diffraction-limit features up to 10 times that of wide-field microscopy's magnification with a field-of-view diameter of up to 9 μm.

  1. Synthesis and characterization of magnetic poly(glycidyl methacrylate) microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Horak, Daniel [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho Sq. 2, 162 06 Prague 6 (Czech Republic)]. E-mail: horak@imc.cas.cz; Petrovsky, Eduard [Geophysical Institute, Academy of Sciences of the Czech Republic, Bocni II/1401, 141 31 Prague 4 (Czech Republic); Kapicka, Ales [Geophysical Institute, Academy of Sciences of the Czech Republic, Bocni II/1401, 141 31 Prague 4 (Czech Republic); Frederichs, Theodor [University of Bremen, Department of Geosciences, GEO I, Klagenfurter Strasse, 28359 Bremen (Germany)

    2007-04-15

    Magnetic nanoparticles encapsulated in poly(glycidyl methacrylate) microspheres were prepared and their detailed structural and magnetic characteristics given. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with dextran, (carboxymethyl)dextran or tetramethylammonium hydroxide. The microspheres were prepared by emulsion or dispersion polymerization of glycidyl methacrylate in the presence of ferrofluid. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres. Blocking temperature was not observed, suggesting the absence of magnetic interactions at low temperatures. This is most probably caused by complete encapsulation and the absence of agglomeration. Such microspheres can be used in biomedical applications.

  2. Textiles with gallic acid microspheres: in vitro release characteristics.

    Science.gov (United States)

    Martí, Meritxell; Martínez, Vanessa; Carreras, Núria; Alonso, Cristina; Lis, Manuel José; Parra, José Luis; Coderch, Luisa

    2014-01-01

    Abstract The aim of this study was to demonstrate the skin penetration of an antioxidant, gallic acid (GA), encapsulated in poly-ε-caprolactone (PCL) microspheres and applied onto textile fabrics, by a specific in vitro percutaneous absorption methodology. Two techniques (particle size distribution and FTIR) were used to characterise the microspheres obtained. The amount of GA-loaded microspheres present in the biofunctional textiles was established before their use as a textile drug delivery system. More absorption and desorption of microspheres with GA for the polyamide fabric were found in comparison with cotton fabric. The percutaneous absorption results indicated that the skin penetration of GA released from PCL-microspheres that were applied directly to the skin was higher than when GA was embedded within biofunctional textiles, in conclusion, an interesting reservoir effect may be promoted when biofunctional textiles were used.

  3. Labelling of silica microspheres with fluorescent lanthanide-doped LaF3 nanocrystals

    International Nuclear Information System (INIS)

    Zhang Yong; Lu Meihua

    2007-01-01

    Fluorescent microspheres have been demonstrated to be useful in a variety of biological applications. Fluorescent silica or polymer microspheres have been produced by incorporation of chromophores into the microspheres, which usually produces microspheres with nonuniform sizes and reduced fluorescence. Here we present a simple and straightforward method to produce silica microspheres with fluorescent lanthanide-doped LaF 3 nanocrystals grown on the surface. LaF 3 nanocrystals are in situ grown on silica microspheres of different sizes to form a raspberry-like structure. The microspheres exhibit strong fluorescence and the colour could be altered by changing the lanthanide ions doped in LaF 3 nanocrystals

  4. Water absorption and its effect on the tensile properties of tapioca starch/polyvinyl alcohol bioplastics

    Science.gov (United States)

    Judawisastra, H.; Sitohang, R. D. R.; Marta, L.; Mardiyati

    2017-07-01

    Tapioca is one of the largest sources of starch and makes it suitable to be used for bioplastic material. Addition of polyvinyl alcohol (PVA) has been shown to successfully reduce the brittleness of starch bioplastic. This study aims to investigate the influence of PVA addition to water absorption behavior and its effect on the tensile properties of tapioca starch/PVA bioplastics, which are still not yet fully understood until now. The bioplastics were prepared by solution casting method at gelatinization temperature, with PVA addition from 0 to 29 wt%. Examinations were carried out by means of water absorption test, tensile test and Fourier Transform Infrared (FTIR) Spectroscopy. Increasing content of PVA, up to 29 wt%, was found to decrease the water absorption of the bioplastics, with the lowest water saturation point of 251%. This is due to the interaction between starch and PVA which reduces the free OH groups in the resulting bioplastics. Consequently, this led to a decrease in water absorption-related deterioration, i.e. tensile properties degradation of the bioplastics. The addition of 29 wt% resulted into the lowest degradation in tensile strength (6%) and stiffness (30%), while accompanied with the highest elongation increase (39%) after water immersion.

  5. Physical Cross-Linking Starch-Based Zwitterionic Hydrogel Exhibiting Excellent Biocompatibility, Protein Resistance, and Biodegradability.

    Science.gov (United States)

    Ye, Lei; Zhang, Yabin; Wang, Qiangsong; Zhou, Xin; Yang, Boguang; Ji, Feng; Dong, Dianyu; Gao, Lina; Cui, Yuanlu; Yao, Fanglian

    2016-06-22

    In this work, a novel starch-based zwitterionic copolymer, starch-graft-poly(sulfobetaine methacrylate) (ST-g-PSBMA), was synthesized via Atom Transfer Radical Polymerization. Starch, which formed the main chain, can be degraded completely in vivo, and the pendent segments of PSBMA endowed the copolymer with excellent protein resistance properties. This ST-g-PSBMA copolymer could self-assemble into a physical hydrogel in normal saline, and studies of the formation mechanism indicated that the generation of the physical hydrogel was driven by electrostatic interactions between PSBMA segments. The obtained hydrogels were subjected to detailed analysis by scanning electron microscopy, swelling ratio, protein resistance, and rheology tests. Toxicity and hemolysis analysis demonstrated that the ST-g-PSBMA hydrogels possess excellent biocompatibility and hemocompatibility. Moreover, the cytokine secretion assays (IL-6, TNF-α, and NO) confirmed that ST-g-PSBMA hydrogels had low potential to trigger the activation of macrophages and were suitable for in vivo biomedical applications. On the basis of these in vitro results, the ST-g-PSBMA hydrogels were implanted in SD rats. The tissue responses to hydrogel implantation and the hydrogel degradation in vivo were determined by histological analysis (Hematoxylin and eosin, Van Gieson, and Masson's Trichrome stains). The results presented in this study demonstrate that the physical cross-linking, starch-based zwitterionic hydrogels possess excellent protein resistance, low macrophage-activation properties, and good biocompatibility, and they are a promising candidate for an in vivo biomedical application platform.

  6. Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency.

    Science.gov (United States)

    Mößeler, Anne; Vagt, Sandra; Beyerbach, Martin; Kamphues, Josef

    2015-01-01

    Although steatorrhea is the most obvious symptom of pancreatic exocrine insufficiency (PEI), enzymatic digestion of protein and starch is also impaired. Low praecaecal digestibility of starch causes a forced microbial fermentation accounting for energy losses and meteorism. To optimise dietetic measures, knowledge of praecaecal digestibility of starch is needed but such information from PEI patients is rare. Minipigs fitted with an ileocaecal fistula with (n = 3) or without (n = 3) pancreatic duct ligation (PL) were used to estimate the rate of praecaecal disappearance (pcD) of starch. Different botanical sources of starch (rice, amaranth, potato, and pea) were fed either raw or cooked. In the controls (C), there was an almost complete pcD (>92%) except for potato starch (61.5%) which was significantly lower. In PL pcD of raw starch was significantly lower for all sources of starch except for amaranth (87.9%). Thermal processing increased pcD in PL, reaching values of C for starch from rice, potato, and pea. This study clearly underlines the need for precise specification of starch used for patients with specific dietetic needs like PEI. Data should be generated in suitable animal models or patients as tests in healthy individuals would not have given similar conclusions.

  7. Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency

    Directory of Open Access Journals (Sweden)

    Anne Mößeler

    2015-01-01

    Full Text Available Although steatorrhea is the most obvious symptom of pancreatic exocrine insufficiency (PEI, enzymatic digestion of protein and starch is also impaired. Low praecaecal digestibility of starch causes a forced microbial fermentation accounting for energy losses and meteorism. To optimise dietetic measures, knowledge of praecaecal digestibility of starch is needed but such information from PEI patients is rare. Minipigs fitted with an ileocaecal fistula with (n=3 or without (n=3 pancreatic duct ligation (PL were used to estimate the rate of praecaecal disappearance (pcD of starch. Different botanical sources of starch (rice, amaranth, potato, and pea were fed either raw or cooked. In the controls (C, there was an almost complete pcD (>92% except for potato starch (61.5% which was significantly lower. In PL pcD of raw starch was significantly lower for all sources of starch except for amaranth (87.9%. Thermal processing increased pcD in PL, reaching values of C for starch from rice, potato, and pea. This study clearly underlines the need for precise specification of starch used for patients with specific dietetic needs like PEI. Data should be generated in suitable animal models or patients as tests in healthy individuals would not have given similar conclusions.

  8. Comparison of gamma radiation effects on natural corn and potato starches and modified cassava starch

    Science.gov (United States)

    Teixeira, Bruna S.; Garcia, Rafael H. L.; Takinami, Patricia Y. I.; del Mastro, Nelida L.

    2018-01-01

    The objective of this work was to evaluate the effect of irradiation treatment on physicochemical properties of three natural polymers, i.e. native potato and corn starches and a typical Brazilian product, cassava starch modified through fermentation -sour cassava- and also to prepare composite hydrocolloid films based on them. Starches were irradiated in a 60Co irradiation chamber in doses up to 15 kGy, dose rate about 1 kGy/h. Differences were found in granule size distribution upon irradiation, mainly for corn and cassava starch but radiation did not cause significant changes in granule morphology. The viscosity of the potato, corn and cassava starches hydrogels decreased as a function of absorbed dose. Comparing non-irradiated and irradiated starches, changes in the Fourier transform infrared (FTIR) spectra in the 2000-1500 cm-1 region for potato and corn starches were observed but not for the cassava starch. Maximum rupture force of the starch-based films was affected differently for each starch type; color analysis showed that doses of 15 kGy promoted a slight rise in the parameter b* (yellow color) while the parameter L* (lightness) was not significantly affected; X-ray diffraction patterns remained almost unchanged by irradiation.

  9. PHYSICOCHEMICAL PROPERTIES OF STARCH-MALTODEXTRIN AND STARCH-MALTODEXTRIN-GLUCOSE SYSTEMS

    Directory of Open Access Journals (Sweden)

    Magdalena Grzelak

    2012-04-01

    Full Text Available Normal 0 21 false false false SK JA X-NONE Starch is a widely used food additive. The addition of other ingredients changes the physical properties of resulting systems. The aim of this study was to investigate the rheological characteristics and susceptibility to retrogradation of starch-maltodextrin and starch-maltodextrin-glucose systems. Flow curves of 5% starch - maltodextrin and starch-maltodextrin-glucose pastes were tested by using rotational rheometer. The susceptibility to retrogradation of 2% pastes starch-maltodextrin and starch-maltodextrin-glucose systems by means of turbidimetric method was evaluated. It was found that all samples (systems were a non-Newtonian, pseudoplastic fluids, with tend to the yield stress. Moreover addition of low and high DE maltodextrins and glucose to the starch caused a decrease in the values of shear stress throughout whole shear rate range. Starch pastes with greater concentration of the maltodextrins had less tendency to retrogradation. Also addition of glucose to starch-maltodextrin systems reduce the susceptibility to retrogradation.10.5219/196

  10. A comparative study of the physicochemical properties of starches ...

    African Journals Online (AJOL)

    Some properties of starches from cassava, potato and sweet potato were compared with cereal starches from maize, wheat, millet and sorghum. The aim was to determine the properties of tuber and root crop starches and compare them with cereal starches in addition to unravelling the potential of commonly grown ...

  11. Differently sized granules from acetylated potato and sweet potato starches differ in the acetyl substitution pattern of their amylose polulations.

    NARCIS (Netherlands)

    Chen Zenghong,; Schols, H.A.; Voragen, A.G.J.

    2004-01-01

    Acetylated potato and sweet potato starches were fractionated according to granule size. From the fractions obtained amylose and amylopectin were isolated and characterized with respect to degree of substitution (DS) and degradability with -amylase, -amylase and amyloglucosidase. The DS of the

  12. Model approach to starch functionality in bread making.

    Science.gov (United States)

    Goesaert, Hans; Leman, Pedro; Delcour, Jan A

    2008-08-13

    We used modified wheat starches in gluten-starch flour models to study the role of starch in bread making. Incorporation of hydroxypropylated starch in the recipe reduced loaf volume and initial crumb firmness and increased crumb gas cell size. Firming rate and firmness after storage increased for loaves containing the least hydroxypropylated starch. Inclusion of cross-linked starch had little effect on loaf volume or crumb structure but increased crumb firmness. The firming rate was mostly similar to that of control samples. Presumably, the moment and extent of starch gelatinization and the concomitant water migration influence the structure formation during baking. Initial bread firmness seems determined by the rigidity of the gelatinized granules and leached amylose. Amylopectin retrogradation and strengthening of a long-range network by intensifying the inter- and intramolecular starch-starch and possibly also starch-gluten interactions (presumably because of water incorporation in retrograded amylopectin crystallites) play an important role in firming.

  13. Evidence that the "waxy" protein of pea (Pisum sativum L.) is not the major starch-granule-bound starch synthase.

    Science.gov (United States)

    Smith, A M

    1990-11-01

    The aim of this work was to identify the starch-granule-bound starch synthase of developing pea embryos. When starch-granule-bound proteins were solubilised by digestion of granules with α-amylase and fractionated on a Mono Q anion-exchange column, activity of starch synthase eluted as three peaks. The distribution of activity in fractions from the column coincided with that of a 77-kDa protein. An antibody to this protein inhibited starch-synthase activity both in solubilised, starch-granule-bound protein and on intact starch granules. Recoveries of activity through extraction, solubilisation and chromatography indicate that this protein is the major, if not the only, form of starch synthase on the starch granule. The major, 59-kDa protein of the pea starch granule is antigenically related to the product of thewaxy locus of potato, which has previously been identified as the starch-granule-bound starch synthase of the tuber. However, the distribution of the 59-kDa protein did not coincide with that of starch-synthase activity in fractions from the Mono Q column. An antibody to the 59-kDa protein did not inhibit starch-synthase activity. The results raise questions about the relationship between "waxy" proteins and starch-granule-bound starch synthases generally.

  14. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Humrickhouse-Helmreich, Carissa J., E-mail: carissahelmreich@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States); Corbin, Rob, E-mail: rcorbin@terrapower.com [TerraPower, LLC, 330 120th Ave NE, Suite 100, Bellevue, WA 98005 (United States); McDeavitt, Sean M., E-mail: mcdeavitt@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States)

    2014-03-15

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  15. Current knowledge on biodegradable microspheres in drug delivery.

    Science.gov (United States)

    Prajapati, Vipul D; Jani, Girish K; Kapadia, Jinita R

    2015-08-01

    Biodegradable microspheres have gained popularity for delivering a wide variety of molecules via various routes. These types of products have been prepared using various natural and synthetic biodegradable polymers through suitable techniques for desired delivery of various challenging molecules. Selection of biodegradable polymers and technique play a key role in desired drug delivery. This review describes an overview of the fundamental knowledge and status of biodegradable microspheres in effective delivery of various molecules via desired routes with consideration of outlines of various compendial and non-compendial biodegradable polymers, formulation techniques and release mechanism of microspheres, patents and commercial biodegradable microspheres. There are various advantages of using biodegradable polymers including promise of development with different types of molecules. Biocompatibility, low dosage and reduced side effects are some reasons why usage biodegradable microspheres have gained in popularity. Selection of biodegradable polymers and formulation techniques to create microspheres is the biggest challenge in research. In the near future, biodegradable microspheres will become the eco-friendly product for drug delivery of various genes, hormones, proteins and peptides at specific site of body for desired periods of time.

  16. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Science.gov (United States)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-03-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time-temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  17. Measurement of thermal diffusivity of depleted uranium metal microspheres

    International Nuclear Information System (INIS)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-01-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal

  18. Pretreated Starch Solutions for Low Environmental Impact Aircraft Deicing

    Science.gov (United States)

    2010-09-01

    20 iii List of Figures Figure 1. Response surface plot of oxidized corn starch solution freezing...Chloroform, sodium hydroxide (NaOH), sulfuric acid (H2SO4), iron(III) EDTA, and pyridine were purchased from JT Baker (Phillipsburg, NJ). Corn starch was...effect of starch to oxidant (H2O2) ratios on freezing point depression of the oxidized starch solution were the initial mass of potato or corn starch

  19. Determination of carbon isotope ratios in plant starch via selective enzymatic hydrolysis

    International Nuclear Information System (INIS)

    Schimmelmann, A.; DeNiro, M.J.

    1983-01-01

    A method for the determination of the carbon isotope ratios in bipolymers hydrolyzed by enzymatic action consists of separating the monomer by passage through a dialysis membrane and then combusting the monomer prior to isotopic analysis. The method is described for application to the analysis of starch, but it should find application for polymers than can be degraded quantitatively to monomers and/or oligomers using specific hydrolytic enzymes

  20. Combination of Poly(lactic) Acid and Starch for Biodegradable Food Packaging

    OpenAIRE

    Muller, Justine; Gonz?lez-Mart?nez, Chelo; Chiralt, Amparo

    2017-01-01

    The massive use of synthetic plastics, in particular in the food packaging area, has a great environmental impact, and alternative more ecologic materials are being required. Poly(lactic) acid (PLA) and starch have been extensively studied as potential replacements for non-degradable petrochemical polymers on the basis of their availability, adequate food contact properties and competitive cost. Nevertheless, both polymers exhibit some drawbacks for packaging uses and need to be adapted to th...

  1. Thyroid artery embolization with microspheres for hyperthyroidism

    International Nuclear Information System (INIS)

    Du Yahui; Zhong Chenfu; Chen Weijun; Zhang Ying; Luo Jun; Li Xiaoguang; Cao Junjie; Gan Changli; Cao Junjie; Gan Changli

    2006-01-01

    Objective: To evaluate the method and efficacy of thyroid artery embolization as a new therapy for hyperthyroidism. Methods: Thirteen patients with hyperthyroidism underwent selective thyroid artery embolization. Totally 25 thyroid arteries were embolized with microspheres. The indications for this therapy were as followings: 1) To give hyperthyroid patients having an alternative for surgical and 131 I treatment, and 2) To provide a new method for those clinically being difficult to get control with medicine. Results: Serum level of thyroid hormones dropped significantly[T3 from 2.84-9.0 ng/ml to 0.8-2.2 ng/ml, T4 from 162.9-277.2 ng/ml to 50-126 ng/ml] and symptoms of hyperthyroidism were under control in 12 patients within 1 month after the embolization. One patient remained no change 1 month later and refused to be embolized again. The symptoms of twelve patients were effectively controlled through low dose antithyroid medication for more than 6 months follow up with no serious complications. Conclusion: Thyroid artery embolization with microspheres is an effective alternative for surgical and 131 I treatment of hyperthyroidism. (authors)

  2. Preparation and properties of polyvinyl alcohol microspheres

    International Nuclear Information System (INIS)

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

    1986-06-01

    Polyvinyl alcohol (PVA) microspheres, having a size range of ∼150- to 250-μm diameter with 1- to 5-μm wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report

  3. Development of nuclear fuel microsphere handling techniques and equipment

    International Nuclear Information System (INIS)

    Mack, J.E.; Suchomel, R.R.; Angelini, P.

    1979-01-01

    Considerable progress has been made in the development of microsphere handling techniques and equipment for nuclear applications. Work at Oak Ridge National Laboratory with microspherical fuel forms dates back to the early sixties with the development of the sol-gel process. Since that time a number of equipment items and systems specifically related to microsphere handling and characterization have been identified and developed for eventual application in a remote recycle facility. These include positive and negative pressure transfer systems, samplers, weighers, a blender-dispenser, and automated devices for particle size distribution and crushing strength analysis. The current status of these and other components and systems is discussed

  4. Development of prilling process for biodegradable microspheres through experimental designs.

    Science.gov (United States)

    Fabien, Violet; Minh-Quan, Le; Michelle, Sergent; Guillaume, Bastiat; Van-Thanh, Tran; Marie-Claire, Venier-Julienne

    2016-02-10

    The prilling process proposes a microparticle formulation easily transferable to the pharmaceutical production, leading to monodispersed and highly controllable microspheres. PLGA microspheres were used for carrying an encapsulated protein and adhered stem cells on its surface, proposing a tool for regeneration therapy against injured tissue. This work focused on the development of the production of PLGA microspheres by the prilling process without toxic solvent. The required production quality needed a complete optimization of the process. Seventeen parameters were studied through experimental designs and led to an acceptable production. The key parameters and mechanisms of formation were highlighted. Copyright © 2015. Published by Elsevier B.V.

  5. Cooking behavior and starch digestibility of NUTRIOSE® (resistant starch) enriched noodles from sweet potato flour and starch.

    Science.gov (United States)

    Menon, Renjusha; Padmaja, G; Sajeev, M S

    2015-09-01

    The effect of a resistant starch source, NUTRIOSE® FB06 at 10%, 15% and 20% in sweet potato flour (SPF) and 5% and 10% in sweet potato starch (SPS) in reducing the starch digestibility and glycaemic index of noodles was investigated. While NUTRIOSE (10%) significantly reduced the cooking loss in SPF noodles, this was enhanced in SPS noodles and guar gum (GG) supplementation reduced CL of both noodles. In vitro starch digestibility (IVSD) was significantly reduced in test noodles compared to 73.6g glucose/100g starch in control SPF and 65.9 g in SPS noodles. Resistant starch (RS) was 54.96% for NUTRIOSE (15%)+GG (1%) fortified SPF noodles and 53.3% for NUTRIOSE (5%)+GG (0.5%) fortified SPS noodles, as against 33.8% and 40.68%, respectively in SPF and SPS controls. Lowest glycaemic index (54.58) and the highest sensory scores (4.23) were obtained for noodles with 15% NUTRIOSE+1% GG. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Degradation of dietary fibre from 'Gari' by faecal bacteria and ...

    African Journals Online (AJOL)

    Dietary fibre (soluble and insoluble fibre) was extracted from 'gari' (a fermented cassava product). The 'gari' fibre was subjected to degradation by faecal microflora and the microbial extracellular enzymes obtained from six clinically healthy adults (S1-S6). Other common components of dietary fibre namely starch, xylan, ...

  7. Characterization of Digestion Resistance Sweet Potato Starch ...

    African Journals Online (AJOL)

    Purpose: To analyze the physicochemical properties and in vitro digestibility of sweet potato starchphosphodiester prepared using sodium trimetaphosphate. Methods: The physicochemical properties of sweet potato starch phosphodiester were analyzed by using infrared spectrometry (IR), differential scanning calorimetry ...

  8. Up-Scaling Production of Carboxymethyl Starch

    International Nuclear Information System (INIS)

    Mohd Hafiz Abdul Nasir; Zainon Othman; Kamaruddin Hashim; Siti Khadijah Abu Hadin; Nurul Nadia Shaaban

    2015-01-01

    Carboxymethyl starch (CMS) is a starch derivative formed by its reaction with sodium monochloroacetate which consist of OH-groups that are partially or completely replaced by ether substitution. Characteristic of CMSS defined by the degree of substitution (DS). DS is defined as the average number of substituents per anhydro glucose unit (AGU), the monomer unit of starch. The upgrading of CMSS production from 10L to 30L requires several experiments with different variable such as amount NaOH, amount of Sago Starch and reaction time. Each will give different DS. Quality control for the product cover moisture, viscosity and paste clarity. Therefore, SOP has been established to control the quality final product. (author)

  9. Production of modified starches by gamma irradiation

    International Nuclear Information System (INIS)

    Kang, Il-Jun; Byun, Myung-Woo; Yook, Hong-Sun; Bae, Chun-Ho; Lee, Hyun-Soo; Kwon, Joong-Ho; Chung, Cha-Kwon

    1999-01-01

    As a new processing method for the production of modified starch, gamma irradiation and four kinds of inorganic peroxides were applied to commercial corn starch. The addition of inorganic peroxides without gamma irradiation or gamma irradiation without the addition of inorganic peroxides effectively decreased initial viscosity, but did not sufficiently keep viscosity stable. The combination of adding ammonium persulfate (APS) and gamma irradiation showed the lowest initial viscosity and the best stability out of the tested four kinds of inorganic peroxides. Among the tested mixing methods of APS, soaking was found to be more effective than dry blending or spraying. Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability became feasible by the control of gamma irradiation dose levels and the amount of added APS to starch

  10. Production of modified starches by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Il-Jun [Department of Food and Nutrition, Hallym University, Chunchon, Kangwon-Do (Korea, Republic of); Byun, Myung-Woo [Department of Food Irradiation, Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Yook, Hong-Sun [Department of Food Irradiation, Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Bae, Chun-Ho [Samyang Genex R and D Center, Yusung-Gu, Taejon (Korea, Republic of); Lee, Hyun-Soo [Samyang Genex R and D Center, Yusung-Gu, Taejon (Korea, Republic of); Kwon, Joong-Ho [Department of Food Science and Technology, Kyungpook National University, Taegu (Korea, Republic of); Chung, Cha-Kwon [Department of Food and Nutrition, Hallym University, Chunchon, Kangwon-Do (Korea, Republic of)

    1999-04-01

    As a new processing method for the production of modified starch, gamma irradiation and four kinds of inorganic peroxides were applied to commercial corn starch. The addition of inorganic peroxides without gamma irradiation or gamma irradiation without the addition of inorganic peroxides effectively decreased initial viscosity, but did not sufficiently keep viscosity stable. The combination of adding ammonium persulfate (APS) and gamma irradiation showed the lowest initial viscosity and the best stability out of the tested four kinds of inorganic peroxides. Among the tested mixing methods of APS, soaking was found to be more effective than dry blending or spraying. Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability became feasible by the control of gamma irradiation dose levels and the amount of added APS to starch.

  11. Dry Starch Powders Modified Teabag Method

    Science.gov (United States)

    The following is a test protocol for a “tea bag analysis” that was conducted on PMN starches by the Corn Refiners Association. This protocol is one approach to providing information on swellability of high molecular weight polymers.

  12. Functional behaviour of polypropylene/ZnO-soluble starch nanocomposites

    International Nuclear Information System (INIS)

    Chandramouleeswaran, Subramani; Mhaske, S T; Kathe, A A; Varadarajan, P V; Prasad, Virendra; Vigneshwaran, Nadanathangam

    2007-01-01

    ZnO-polypropylene nanocomposites (nano-PP) were prepared using nanoparticles of ZnO stabilized by soluble starch (nano-ZnO) as filler in PP by the melt mixing process. X-ray diffraction (XRD) and other spectroscopic analysis-ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and photoluminescence-revealed the presence and characteristics of nano-ZnO in the composites. The presence of ZnO imparts whiteness, while starch increased the yellowing of polymers. The nanocomposites were analyzed for changes in optical, mechanical, electrical and rheological properties, as influenced by the increasing concentration of nano-ZnO. The mechanical properties were marginally increased and the dielectric strength of the nano-PP increased to a notable level. By monitoring the evolution of the carbonyl absorption bands from FTIR analysis, the efficacy of nano-ZnO in the reduction of photo-degradation due to UV irradiation was demonstrated. The excellent antibacterial activity exhibited by nano-ZnO impregnated PP against two human pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumoniae, makes it a suitable candidate for food packaging applications

  13. Functional behaviour of polypropylene/ZnO soluble starch nanocomposites

    Science.gov (United States)

    Chandramouleeswaran, Subramani; Mhaske, S. T.; Kathe, A. A.; Varadarajan, P. V.; Prasad, Virendra; Vigneshwaran, Nadanathangam

    2007-09-01

    ZnO-polypropylene nanocomposites (nano-PP) were prepared using nanoparticles of ZnO stabilized by soluble starch (nano-ZnO) as filler in PP by the melt mixing process. X-ray diffraction (XRD) and other spectroscopic analysis—ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) and photoluminescence—revealed the presence and characteristics of nano-ZnO in the composites. The presence of ZnO imparts whiteness, while starch increased the yellowing of polymers. The nanocomposites were analyzed for changes in optical, mechanical, electrical and rheological properties, as influenced by the increasing concentration of nano-ZnO. The mechanical properties were marginally increased and the dielectric strength of the nano-PP increased to a notable level. By monitoring the evolution of the carbonyl absorption bands from FTIR analysis, the efficacy of nano-ZnO in the reduction of photo-degradation due to UV irradiation was demonstrated. The excellent antibacterial activity exhibited by nano-ZnO impregnated PP against two human pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumoniae, makes it a suitable candidate for food packaging applications.

  14. Characterization of Starch Edible Films with Different Essential Oils Addition

    Directory of Open Access Journals (Sweden)

    Šuput Danijela

    2016-12-01

    Full Text Available This study investigated properties of starch-based edible films with oregano and black cumin essential oil addition. Essential oils addition positively affected film swelling (decreased due to essential oil addition, mechanical properties (tensile strength decreased while elongation at break increased, and water vapor barrier properties (decreased along with essential oils addition. Control film did not have any biological activity, which proves the need for essential oils addition in order to obtain active packaging. Oregano oil was more effective in terms of biological activity. Endothermal peak, above 200°C, represents total thermal degradation of edible films. Diffraction pattern of control film showed significant destruction of A-type crystal structure. Addition of essential oils resulted in peak shape change: diffraction peaks became narrower. Principal Component Analysis has been used to assess the effect of essential oils addition on final starch-based edible films characteristics with the aim to reveal directions for the film characteristics improvement, since the next phase will be optimal film application for food packaging.

  15. Physicochemical and binder properties of starch obtained from Cyperus esculentus.

    Science.gov (United States)

    Manek, Rahul V; Builders, Philip F; Kolling, William M; Emeje, Martins; Kunle, Olobayo O

    2012-06-01

    The purpose of this study was to isolate starch from the tubers of Cyperus esculentus L. and evaluate its physicochemical and binder properties. Extraction of starch using sodium metabisulfite yielded 37 g of starch per 100 g of the tubers. Scanning electron microscopy indicated that Cyperus starch consists of oval to elliptical particles with a smooth surface. Cyperus starch demonstrates a narrow particle size distribution with a mean of 8.25 μm. Cyperus starch conforms well to United States Pharmacopeia standards established for widely used starches like maize and potato. The X-ray powder diffraction pattern and moisture sorption profile of Cyperus starch were comparable to that of maize starch. Cyperus starch had lower swelling power than maize and potato starch, indicative of stronger associative forces within the granules. Carr's index and Hausner ratio indicate that Cyperus starch should have comparable flow properties with respect to maize and potato starch. Cyperus starch was employed as binder for the formulation of metronidazole tablets. Formulations containing 5%, 7.5%, and 10% Cyperus starch were compared with those containing 10% potato starch. At 10% binder concentration, the tablets containing Cyperus starch exhibited better hardness and negligible friability as compared with those with potato starch. Although the binder concentration had a significant effect on the disintegration time of the tablets, it did not seem to affect the dissolution profile. These results indicate that Cyperus starch provides excellent binding properties without compromising drug release characteristics and should be explored in pharmaceutical formulations.

  16. Resistant starch: an indigestible fraction of foods

    Directory of Open Access Journals (Sweden)

    Saura Calixto, F.

    1991-06-01

    Full Text Available Resistant starch (RS, the dietary starch that scape digestion in the small intestine, can yields up to 20% of the starch in cereal and legume products. Several fractions contribute to the total RS of foods: retrograded amylose, starch inaccessible to digestive enzymes because of mechanical barriers, chemically modified starch fragments, undigested starch due to α-amylase inhibitors and starch complexed with other food components. RS is formed in products processed following heat treatments (baking, extrusion, autoclaving, etc.. RS produces significant fecal bulking and is partially fermentable by anaerobic bacteria of the colon. On the other hand, the relation of resistant starch with the glucose and insulin response in human subjects is an important nutritional effect. RS analytical methods are reported.

    El almidón resistente (RS, fracción de almidón de la dieta que no es digerido en el intestino delgado, puede alcanzar hasta un 20% del almidón en productos derivados de cereales y legumbres. Varias fracciones contribuyen al contenido total de almidón resistente: amilosa retrogradada, almidón inaccesible físicamente a los enzimas digestivos, almidón indigestible debido a inhibición de α-amilasas y almidón complejado con otros constituyentes de los alimentos. El almidón resistente se forma en productos que han sufrido tratamientos térmicos (panificación, extrusión, autoclave, etc. El RS aumenta el volumen de heces y es fermentado parcialmente en el colon por bacterias anaeróbicas. Igualmente, está relacionado con los niveles de glucosa en sangre y la respuesta de insulina en humanos. Se describen los métodos analíticos para su determinación.

  17. Biodegradable starch-based polymeric materials

    Science.gov (United States)

    Suvorova, Anna I.; Tyukova, Irina S.; Trufanova, Elena I.

    2000-05-01

    The effects of low-molecular-weight additives, temperature and mechanical action on the structure and properties of starch are discussed. Special attention is given to mixtures of starch with synthetic polymers, e.g., co-polymers of ethylene with vinyl acetate, vinyl alcohol, acrylic acid, cellulose derivatives and other natural polymers. These mixtures can be used in the development of novel environmentally safe materials (films, coatings, packaging materials) and various articles for short-term use. The bibliography includes 105 references.

  18. Thermoplastic Starch: Improving their Barrier Properties

    OpenAIRE

    ORTEGA-TORO, RODRIGO; Collazo-Bigliardi, Sofia; Talens Oliag, Pau; Chiralt Boix, Mª Amparo

    2016-01-01

    [EN] There are several strategies for improving functional properties of starch based materials. Blending with more hydrophobic compounds and bilayer formation are the most common methods. Barrier properties of several formulations obtained by different processing methods were measured. The properties of some obtained materials were compared with those usually employed in food packaging. The most promising materials were those starch PCL blends, compatibilized with grafted poly(ε-caprolactone...

  19. Heat expanded starch-based compositions.

    Science.gov (United States)

    Glenn, Gregory M; Klamczynski, Artur K; Holtman, Kevin M; Shey, Justin; Chiou, Bor-Sen; Berrios, Jose; Wood, Delilah; Orts, William J; Imam, Syed H

    2007-05-16

    A heat expansion process similar to that used for expanded bead polystyrene was used to expand starch-based compositions. Foam beads made by solvent extraction had the appearance of polystyrene beads but did not expand when heated due to an open-cell structure. Nonporous beads, pellets, or particles were made by extrusion or by drying and milling cooked starch slurries. The samples expanded into a low-density foam by heating 190-210 degrees C for more than 20 s at ambient pressures. Formulations containing starch (50-85%), sorbitol (5-15%), glycerol (4-12%), ethylene vinyl alcohol (EVAL, 5-15%), and water (10-20%) were studied. The bulk density was negatively correlated to sorbitol, glycerol, and water content. Increasing the EVAL content increased the bulk density, especially at concentrations higher than 15%. Poly(vinyl alcohol) (PVAL) increased the bulk density more than EVAL. The bulk density was lowest in samples made of wheat and potato starch as compared to corn starch. The expansion temperature for the starch pellets decreased more than 20 degrees C as the moisture content was increased from 10 to 25%. The addition of EVAL in the formulations decreased the equilibrium moisture content of the foam and reduced the water absorption during a 1 h soaking period.

  20. Characteristics of starch-based films plasticised by glycerol and by the ionic liquid 1-ethyl-3-methylimidazolium acetate: a comparative study.

    Science.gov (United States)

    Xie, Fengwei; Flanagan, Bernadine M; Li, Ming; Sangwan, Parveen; Truss, Rowan W; Halley, Peter J; Strounina, Ekaterina V; Whittaker, Andrew K; Gidley, Michael J; Dean, Katherine M; Shamshina, Julia L; Rogers, Robin D; McNally, Tony

    2014-10-13

    This paper reports the plasticisation effect of the ionic liquid, 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]), as compared with the traditionally used plasticiser, glycerol, on the characteristics of starch-based films. For minimising the additional effect of processing, a simple compression moulding process (which involves minimal shear) was used for preparation of starch-based films. The results show that [Emim][OAc] was favourable for plasticisation, i.e., disruption of starch granules (by scanning electron microscopy), and could result in a more amorphous structure in the starch-based materials (by X-ray diffraction and dynamic mechanical analysis). (13)C CP/MAS and SPE/MAS NMR spectroscopy revealed that not only was the crystallinity reduced by [Emim][OAc], but also the amorphous starch present was plasticised to a more mobile form as indicated by the appearance of amorphous starch in the SPE/MAS spectrum. Mechanical results illustrate that, when either glycerol or [Emim][OAc] was used, a higher plasticiser content could contribute to higher flexibility. In spite of the accelerated thermal degradation of starch by [Emim][OAc] as shown by thermogravimetric analysis, the biodegradation study revealed the antimicrobial effect of [Emim][OAc] on the starch-based materials. Considering the high-amylose starch used here which is typically difficult to gelatinise in a traditional plasticiser (water and/or glycerol), [Emim][OAc] is demonstrated to be a promising plasticiser for starch to develop "green" flexible antimicrobial materials for novel applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Influence of phosphate esters on the annealing properties of starch

    DEFF Research Database (Denmark)

    Wischmann, Bente; Muhrbeck, Per

    1998-01-01

    The effects of annealing on native potato, waxy maize, and phosphorylated waxy maize starches were compared. Phosphorylated waxy maize starch responded to annealing in a manner between that of the naturally phosphorylated potato starch and that of the native waxy maize starch. The gelatinisation...... end-point temperature was increased, whereas in the native waxy maize it was decreased. On the other hand, the onset temperature change was much larger in potato starch than in the two waxy maize starches. Steeping also yielded intermediate effects on the phosphorylated waxy maize starch....... It was concluded that the phosphate groups have similar effects as they do in the native, naturally phosphorylated potato starch, although the substitution pattern is not entirely the same in the artificially phosphorylated starch....

  2. Radiation grafting of styrene on starch with high efficiency

    Science.gov (United States)

    Sheikh, N.; Akhavan, A.; Ataeivarjovi, E.

    2013-04-01

    Wheat starch grafted with polystyrene (PS-g-starch) was synthesized via polymerization grafting of styrene on starch by gamma-ray. The effects of starch/styrene weight ratio, and amount of applied doses (5-40 kGy) on the percentage of grafting, G (%), were investigated. The results showed that G (%) increased with increasing starch content. The optimum condition, starch/styrene weight ratio 1/3 and the applied dose 10 kGy, led to 252.9% of grafting. The obtained graft copolymer was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, and scanning electron microscopy. FTIR spectroscopy as well as the XRD analysis exhibited the changes in chemical and crystalline structure of starch after grafting reaction. TGA demonstrated the changes in thermal stability of PS-g-starch copolymer. SEM micrographs indicated porous patches of PS adhering on the starch.

  3. Anthocyanin and proanthocyanidin contents, antioxidant activity, and in situ degradability of black and red rice grains.

    Science.gov (United States)

    Hosoda, Kenji; Sasahara, Hideki; Matsushita, Kei; Tamura, Yasuaki; Miyaji, Makoto; Matsuyama, Hiroki

    2018-03-02

    An experiment was conducted to assess the antioxidant contents and activities of colored rice grains and to evaluate their nutritive characteristics in terms of chemical composition and in situ ruminal degradation. Ten cultivars of colored rice grains (Oryza sativa L.) collected from several areas of Japan were studied, and control rice without pigment, maize, barley, and wheat grains were used as control grains. Their chemical compositions, pigment, polyphenol contents, total antioxidant capacity (TAC), and degradation characteristics were determined. The starch contents of the colored rice grains were in the range of 73.5-79.6%, similar to that of the control rice grain. The black and red rice grains contained anthocyanin (maximum: 5045.6 µg/g) and proanthocyanidin (maximum: 3060.6 µg/g) at high concentrations as their principal pigments, respectively. There were significantly (p rice grains, indicating that the increase in pigment contents also contributed to the increased polyphenol content and TAC values in the colored rice grains. The dry matter and starch degradation characteristics, as represented by c (fractional degradation rate of slowly degradable fraction) and by the effective degradability, of the colored rice grains and the control rice grain were ranked as follows among commonly used grains: wheat > barley ≥ rice > maize. The colored rice grains also included the most-digestible starch, since their potential degradable fraction and actual degradability at 48 h incubation were almost 100%. Colored rice grains have high potential to be used as antioxidant sources in addition to starch sources in ruminants.

  4. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  5. Novel Synthesis of Yttrium Phosphate Microspheres for Radioembolization of Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kawashita, M; Matsui, N; Li, Z [Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University (Japan); Miyazaki, T, E-mail: m-kawa@ecei.tohoku.ac.jp [Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology (Japan)

    2011-10-29

    Chemically durable microspheres containing yttrium and/or phosphorus are useful for intra-arterial radiotherapy. In the present study, we attempted to prepare yttrium phosphate (YPO{sub 4}) microspheres with high chemical durability as well as smooth surface and investigated their chemical durability in simulated body environment. YPO{sub 4} microspheres with smooth surface around 25 {mu}m were successfully obtained, when gelatin droplets containing YPO{sub 4} precursor was cooled to be solidified in water-in-oil emulsion and then heat-treated at 1100 deg. C. The chemical durability of the heat-treated microspheres in simulated body fluid at pH =6 and 7 was high enough for clinical application of radioembolic therapy of cancer.

  6. Properties of rigid polyurethane foams filled with glass microspheres

    Science.gov (United States)

    Yakushin, V.; Bel'kova, L.; Sevastyanova, I.

    2012-11-01

    The effect of hollow glass microspheres with a density of 125 kg/m3 on the properties of low-density (54-90 kg/m3) rigid polyurethane foams is investigated. The thermal expansion coefficient of the foams and their properties in tension and compression in relation to the content of the microspheres (0.5-5 wt.%) are determined. An increase in the characteristics of the material in compression in the foam rise direction with increasing content of filler is revealed. The limiting content of the microspheres above which the mechanical characteristics of the filled foams begin to decrease is found. The distribution of the microspheres in elements of the cellular structure of the polyurethane foams is examined.

  7. Investigation of defects on PAMS microspheres fabricated with microencapsulation method

    International Nuclear Information System (INIS)

    Chen Sufen; Li Bo; Liu Yiyang; Zhang Zhanwen; Qi Xiaobo

    2012-01-01

    Poly-(α-methylstyrene) (PAMS) microspheres were fabricated with W1/O/W2 double emulsion microencapsulation method, and the effects of polyvinylalcohol (PVA) and CaCl 2 weight concentrations and the O/W2 phase ratio on the percentages of defected PAMS microspheres were studied. The weight concentrations of PVA and CaCl 2 and the O/W2 phase ratio in the fabrication process of PAMS microspheres were optimized. The results show that, for the three parameters being 1.0%, 1.5%, and 0.01, respectively, the percentage of the defect-free PAMS microspheres without vacuoles in the shell wall can be up to 60%. (authors)

  8. Preparation and In-vitro Evaluation of Metformin Microspheres Using ...

    African Journals Online (AJOL)

    . Methods: Metformin microspheres were prepared by non-aqueous solvent evaporation method using various polymers, including ethylcellulose (EC), hydroxypropyl methylcellulose (HPMC), carbopol 934P (CA) and chitosan (CH). The effect ...

  9. Engineering Potato Starch with a Higher Phosphate Content.

    Directory of Open Access Journals (Sweden)

    Xuan Xu

    Full Text Available Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (dephosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal. Interestingly, expression of an (engineered laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf. Modified starches exhibited altered granule morphology and size compared to the control. About 20-30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself.

  10. Facile preparation of hierarchically porous polymer microspheres for superhydrophobic coating

    Science.gov (United States)

    Gao, Jiefeng; Wong, Julia Shuk-Ping; Hu, Mingjun; Li, Wan; Li, Robert. K. Y.

    2013-12-01

    A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during electrospraying influence the morphology of finally obtained products. In this paper, the influence of polymer concentration, the weight ratio between nonsolvent and polymer and the flowing rate on the morphology of the porous microsphere is carefully studied. The hierarchically porous microsphere significantly increases the surface roughness and thus the hydrophobicity, and the contact angle can reach as high as 152.2 +/- 1.2°. This nonsolvent assisted electrospraying opens a new way to fabricate superhydrophobic coating materials.A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during

  11. Application of sustained release microsphere in hypoparathyroidism after thyroid surgery

    Directory of Open Access Journals (Sweden)

    Pan Ming

    2017-01-01

    Full Text Available Hypoparathyroidism (HypoPT is one of the most common complications after thyroid surgery. The parathyroid hormone-controlled delivery system is one of the most significant therapies for hypothyroidism after thyroid and parathyroid surgery. The character of biodegradability and the slow release of PTH of the Sustained release microspheres were widely concerned. The authors present the research progress in sustained release microspheres loaded with PTH from the character, material, fabrication and application.

  12. Formulation and Evaluation of Mucoadhesive Microspheres of Lamivudine

    OpenAIRE

    Aliya Parveen; Iizhar Ahmed Syed

    2014-01-01

    The aim of the present work was to prepare and evaluate mucoadhesive microspheres of Lamivudine. Microspheres were formulated using sodium alginate (5%) with mucoadhesive polymer (Chitosan 1%) and copolymer Sodium CMC HPMC, Xanthan gum (XG) in concentration of 1% (Chitosan1% + HPMC1%) (1%) retarding agents and 10% of Calcium chloride (CaCl2), Aluminum sulphate (AlSO4) as cross linking agents by employing Ionic Gelation Technique. The particle size was characterized for by scanning electron mi...

  13. In vitro starch digestion correlates well with rate and extent of starch digestion in broiler chickens

    NARCIS (Netherlands)

    Weurding, R.E.; Veldman, R.; Veen, W.A.G.; Aar, van der P.J.; Verstegen, M.W.A.

    2001-01-01

    Current feed evaluation systems for poultry are based on digested components (fat, protein and nitrogen-free extracts). Digestible starch is the most important energy source in broiler chicken feeds and is part of the nitrogen-free extract fraction. Digestible starch may be predicted using an in

  14. Green starch conversions : Studies on starch acetylation in densified CO2

    NARCIS (Netherlands)

    Muljana, Henky; Picchioni, Francesco; Heeres, Hero J.; Janssen, Leon P. B. M.

    2010-01-01

    The acetylation of potato starch with acetic anhydride (AAH) and sodium acetate (NaOAc) as catalyst in densified CO2 was explored in a batch reactor setup. The effects of process variables such as pressure (6-9.8 MPa), temperature (40-90 degrees C), AAH to starch ratio (2-5 mol/mol AGU), NaOAc to

  15. Surface-associated proteins of wheat starch granules: suitability of wheat starch for celiac patients.

    Science.gov (United States)

    Kasarda, Donald D; Dupont, Frances M; Vensel, William H; Altenbach, Susan B; Lopez, Rocio; Tanaka, Charlene K; Hurkman, William J

    2008-11-12

    Wheat starch is used to make baked products for celiac patients in several European countries but is avoided in the United States because of uncertainty about the amounts of associated grain storage (gluten) proteins. People with celiac disease (CD) must avoid wheat, rye, and barley proteins and products that contain them. These proteins are capable of initiating damage to the absorptive lining of the small intestine in CD patients, apparently as a consequence of undesirable interactions with the innate and adaptive immune systems. In this study, starch surface-associated proteins were extracted from four commercial wheat starches, fractionated by high-performance liquid chromatography and gel electrophoresis, and identified by tandem mass spectrometry analysis. More than 150 proteins were identified, many of which (for example, histones, purothionins, and glutenins) had not been recognized previously as starch-associated. The commercial starches were analyzed by the R-5 enzyme-linked immunosorbent assay method to estimate the amount of harmful gluten protein present. One of these starches had a low gluten content of 7 ppm and actually fell within the range proposed as a new Codex Alimentarius Standard for naturally gluten-free foods (maximum 20 ppm). This low level of gluten indicates that the starch should be especially suitable for use by celiac patients, although wheat starches with levels up to 100 ppm are deemed safe in the proposed Codex standards.

  16. Characterization of starch films containing starch nanoparticles: part 1: physical and mechanical properties.

    Science.gov (United States)

    Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

    2013-07-25

    We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3°C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100°C. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Effect of gamma irradiation on thermophysical properties of plasticized starch and starch surfactant films

    Science.gov (United States)

    Cieśla, Krystyna; Watzeels, Nick; Rahier, Hubert

    2014-06-01

    In this work the influence of gamma irradiation on the thermomechanical properties of the films formed in potato starch-glycerol and potato starch-glycerol-surfactant systems were examined by Dynamic Mechanical Analysis, DMA, and Differential Scanning Calorimetry, DSC, and the results were correlated to the amount of the volatile fraction in the films.

  18. Formulation and characterization of catalase in albumin microspheres.

    Science.gov (United States)

    Siwale, Rodney C; Oettinger, Carl W; Pai, S Balakrishna; Addo, Richard; Uddin, Nasir; Siddig, Aladin; D'Souza, Martin J

    2009-08-01

    Catalase in albumin microspheres were formulated for intravenous administration to antagonize the effects of over-production of reactive oxygenated species (ROS) such as hydrogen peroxide (H(2)O(2)) in septic shock. The aim was to increase effective half-life of catalase and take advantage of the phagocytic uptake of the encapsulated catalase by the vascular endothelium. Catalase microspheres were prepared by spray-drying. The microspheres were evaluated for particle size, particle shape and surface morphology by scanning electron microscopy (SEM), drug encapsulation efficiency, chemical stability, thermal stability and in vitro drug release characteristics. The microspheres had a mean particle size of 4.7 +/- 2 microm, optimal for phagocytic uptake, as demonstrated by Makino et al. SEM revealed that microspheres were spherical with smooth surface morphology. An encapsulation efficiency of 91.5 +/- 3% was achieved and the encapsulated catalase was chemically and thermally stable. Application of in vitro drug release data to the Higuchi kinetic equation indicated matrix diffusion-controlled catalase release from albumin microspheres.

  19. Synthesis and characterization of Supeparamagnetics Microspheres (PMMA via suspension polymerization

    Directory of Open Access Journals (Sweden)

    Paulo Emilio Feuser

    2014-02-01

    Full Text Available Magnetics nanoparticles (NPMs has found many applications in biomedical and technological areas. The objective of this work is the preparation and characterization of PMMA microspheres containing NPMs coated with oleic acid (NPMs-AO. For the preparation of MNPs-AO was used the coprecipitation method in an aqueous medium. For the preparation of the superparamagnetic microspheres used in suspension polymerization technique. The microspheres showed a size distribution particles of approximately 150um and a spherical morphology. From the analysis of gel permeation chromatography (GPC determined the number average molecular weight (Mw of the magnetics microspheres and there was a variation in the Mw depending on the concentration of MNPs-AO in this reaction. To analyze the magnetic properties used the vibrating sample magnetometer (MAV. The microspheres showed superparamagnetic properties and a value of saturation magnetization (Ms of about 8 emu/g MNPs. Therefore you can conclude that it is possible to obtain superparamagnetics microspheres for a particular application, either, biomedical or technological.

  20. Innovative hydrogen storage in hollow glass-microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Keding, M.; Schmid, G.; Tajmar, M. [Austrian Research Centers, Vienna (Austria)

    2009-07-01

    Hydrogen storage technologies are becoming increasingly important for a number of future applications. The Austrian Research Centers (ARC) are developing a unique hydrogen storage system that combines the advantages of both hollow glass microsphere and chemical compound hydrogen storage, but eliminates their respective drawbacks. Water is utilized as a functional liquid to carry the hollow glass microspheres that are loaded with up to 700 bar of hydrogen gas. Sodium borohydride (NaBH{sub 4}) is then injected together with the glass microspheres into a reaction chamber where the water reacts catalytically with the NaBH{sub 4} producing hydrogen and heat. The heat is then utilized to release the hydrogen from the hollow glass microspheres providing a double hydrogen generation process without any external energy or heat during storage or gas release. The paper described this hydrogen storage system with particular reference to microspheres, the coating process, the experimental facility and NaBH{sub 4} test results. It was concluded that hydrogen storage and production on demand is possible with microspheres and sodium borohydride solution. 9 refs., 16 figs.