Evidence of size-selective evolution in the fighting conch from prehistoric subsistence harvesting.

Science.gov (United States)

O'Dea, Aaron; Shaffer, Marian Lynne; Doughty, Douglas R; Wake, Thomas A; Rodriguez, Felix A

2014-05-07

Intensive size-selective harvesting can drive evolution of sexual maturity at smaller body size. Conversely, prehistoric, low-intensity subsistence harvesting is not considered an effective agent of size-selective evolution. Uniting archaeological, palaeontological and contemporary material, we show that size at sexual maturity in the edible conch Strombus pugilis declined significantly from pre-human (approx. 7 ka) to prehistoric times (approx. 1 ka) and again to the present day. Size at maturity also fell from early- to late-prehistoric periods, synchronous with an increase in harvesting intensity as other resources became depleted. A consequence of declining size at maturity is that early prehistoric harvesters would have received two-thirds more meat per conch than contemporary harvesters. After exploring the potential effects of selection biases, demographic shifts, environmental change and habitat alteration, these observations collectively implicate prehistoric subsistence harvesting as an agent of size-selective evolution with long-term detrimental consequences. We observe that contemporary populations that are protected from harvesting are slightly larger at maturity, suggesting that halting or even reversing thousands of years of size-selective evolution may be possible.

The vascularized groin lymph node flap (VGLN): Anatomical study and flap planning using multi-detector CT scanner. The golden triangle for flap harvesting.

Science.gov (United States)

Zeltzer, Assaf A; Anzarut, Alexander; Braeckmans, Delphine; Seidenstuecker, Katrin; Hendrickx, Benoit; Van Hedent, Eddy; Hamdi, Moustapha

2017-09-01

A growing number of surgeons perform lymph node transfers for the treatment of lymphedema. When harvesting a vascularized lymph node groin flap (VGLNF) one of the major concerns is the potential risk of iatrogenic lymphedema of the donor-site. This article helps understanding of the lymph node distribution of the groin in order to minimize this risk. Fifty consecutive patients undergoing abdominal mapping by multi-detector CT scanner were included and 100 groins analyzed. The groin was divided in three zones (of which zone II is the safe zone) and lymph nodes were counted and mapped with their distances to anatomic landmarks. Further node units were plotted and counted. The average age was 48 years. A mean number of nodes of 6.5/groin was found. In zone II, which is our zone of interest a mean of 3.1 nodes were counted with a mean size of 7.8 mm. In three patients no nodes were found in zone II. In five patients nodes were seen in zone II but were not sufficient in size or number to be considered a lymph node unit. On average the lymph node unit in zone II was found to be 48.3 mm from the pubic tubercle when projected on a line from the pubic tubercle to the anterior superior iliac spine, 16.0 mm caudal to this line, and 20.4 mm above the groin crease. On average the lymph node unit was a mean of 41.7 mm lateral to the SCIV-SIEV confluence. This study provides increased understanding of the lymphatic anatomy in zone II of the groin flap and suggests a refined technique for designing the VGLNF. As with any flap there is a degree of individual patient variability. However, having information on the most common anatomy and flap design is of great value. © 2017 Wiley Periodicals, Inc.

Normal mediastinal lymph node size and shape; CT and cadaver study

International Nuclear Information System (INIS)

Im, Chung Kie; Lee, Kyung Soo; Han, Man Chung; Kim, Chu Wan

1985-01-01

With the view point of size, shape and arrangement pattern, authors present normal mediastinal lymph node from the analysis of 61 cases of CT scan and multidirectional section of 2 cadavers. The result were as follows: 1. Transverse diameter of the lymph nodes, demonstrated in cadaver section, was 3 to 6mm in upper paratracheal area and 5 to 14mm in juxta-carinal and AP-window area. Arrangement of the lymph nodes showed tendency of longitudinal direction in lower paratracheal, and juxtacarinal area, while that of AP window showed tendency of AP direction as long axis. 2. Mean and the largest size of the lymph nodes demonstrated in CT scan were 3.7mm, 8mm in upper paratracheal area, and 6mm, 12mm in lower paratracheal area, and 7.1mm, 14mm in juxtacarinal area, and 6.3mm and 11mm in aorticopulmonary window area. 3. Size of the lymph nodes in CT scan showed linear increasing tendency according to increasing age (y=0.32, p<0.005). 4. Shape of the lymph nodes in CT scan were mostly round in upper paratracheal area while that of aorticopulmonary window showed higher incidence of oval and elongated shape. 5. Recommended size criterior of abnormal lymph node is 10mm in upper paratracheal area and 15mm in the other area

Small-Sized Whole-Tree Harvesting in Finland

Energy Technology Data Exchange (ETDEWEB)

Kaerhae, Kalle [Metsaeteho Oy, Helsinki (Finland)

2006-07-15

In Finland, there are two mechanized harvesting systems used for small diameter (d{sub 1.3}= 10 cm) thinning wood: 1) the traditional two-machine (harvester and forwarder) system, and 2) the harwarder system (i.e. the same machine performs both felling and haulage to the roadside). At present, there are more than 20 energy wood harwarders in use in Finland. However, there have been no comprehensive studies carried out on the energy wood harwarders. This paper looks into the productivity results obtained with energy wood harwarders. In addition, the energy wood harvesting costs for harwarders are compared with those of the two-machine system. The results clearly indicated what kind of machine resources can be profitably allocated to different whole-tree harvesting sites. The energy wood harwarders should be directed towards harvesting sites where the forwarding distances are small, the trees harvested are relatively small, and the total volume of energy wood removed is quite low. Respectively, when the stem size removed is relatively large in young stands, and the forest haulage distances are long, the traditional two-machine system is more competitive.

An energy harvesting system using the wind-induced vibration of a stay cable for powering a wireless sensor node

International Nuclear Information System (INIS)

Jung, Hyung-Jo; Kim, In-Ho; Jang, Seon-Jun

2011-01-01

This paper proposes an electromagnetic energy harvesting system, which utilizes the wind-induced vibration of a stay cable, and investigates its feasibility for powering a wireless sensor node on the cable through numerical simulations as well as experimental tests. To this end, the ambient acceleration responses of a stay cable installed in an in-service cable-stayed bridge are measured, and then they are used as input excitations in cases of both numerical simulations and experimental tests to evaluate the performance of the proposed energy harvesting system. The results of the feasibility test demonstrate that the proposed system generates sufficient electricity for operation of a wireless sensor node attached on the cable under the moderate wind conditions

SIVEH: Numerical Computing Simulation of Wireless Energy-Harvesting Sensor Nodes

Directory of Open Access Journals (Sweden)

Pedro Yuste

2013-09-01

Full Text Available The paper presents a numerical energy harvesting model for sensor nodes, SIVEH (Simulator I–V for EH, based on I–V hardware tracking. I–V tracking is demonstrated to be more accurate than traditional energy modeling techniques when some of the components present different power dissipation at either different operating voltages or drawn currents. SIVEH numerical computing allows fast simulation of long periods of time—days, weeks, months or years—using real solar radiation curves. Moreover, SIVEH modeling has been enhanced with sleep time rate dynamic adjustment, while seeking energy-neutral operation. This paper presents the model description, a functional verification and a critical comparison with the classic energy approach.

Prognostic significance of the total number of harvested lymph nodes for lymph node-negative gastric cancer patients.

Science.gov (United States)

Ji, Xin; Bu, Zhao-De; Li, Zi-Yu; Wu, Ai-Wen; Zhang, Lian-Hai; Zhang, Ji; Wu, Xiao-Jiang; Zong, Xiang-Long; Li, Shuang-Xi; Shan, Fei; Jia, Zi-Yu; Ji, Jia-Fu

2017-08-22

The relationship between the number of harvested lymph nodes (HLNs) and prognosis of gastric cancer patients without an involvement of lymph nodes has not been well-evaluated. The objective of this study is to further explore this issue. We collected data from 399 gastric cancer patients between November 2006 and October 2011. All of them were without metastatic lymph nodes. Survival analyses showed that statistically significant differences existed in the survival outcomes between the two groups allocated by the total number of HLNs ranging from 16 to 22. Therefore, we adopted 22 as the cut-off value of the total number of HLNs for grouping (group A: HLNs <22; group B: HLNs≥22). The intraoperative and postoperative characteristics, including operative blood loss (P=0.096), operation time (P=0.430), postoperative hospital stay (P=0.142), complications (P=0.552), rate of reoperation (P=0.966) and postoperative mortality (P=1.000), were comparable between the two groups. T-stage-stratified Kaplan-Meier analyses revealed that the 5-year survival rate of patients at the T4 stage was better in group B than in group A (76.9% vs. 58.5%; P=0.004). An analysis of multiple factors elucidated that the total number of HLNs, T stage, operation time and age were independently correlated factors of prognosis. Regarding gastric cancer patients without the involvement of lymph nodes, an HLN number ≥22 would be helpful in prolonging their overall survival, especially for those at T4 stage. The total number of HLNs was an independent prognostic factor for this population of patients.

Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications

Science.gov (United States)

Khan, Farid Ullah; Khattak, Muhammad Umair

2016-02-01

Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10-6 μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment.

Energy-autonomous wireless sensor nodes for automotive applications, powered by thermoelectric energy harvesting

International Nuclear Information System (INIS)

Mehne, P.; Lickert, F.; Bäumker, E.; Kroener, M.; Woias, P.

2016-01-01

In this paper we will first present the measurement of temperatures on different positions at a diesel-powered car. As a result, several locations are identified as suitable to implement a wireless sensor node powered by thermal energy harvesting. Based on the data gained a thermoelectric generator (TEG) has been selected, and measurements of energy generation have been performed. Further, a complete energy-autonomous wireless sensor node was designed, including the TEG with its mounting bracket, an electronic power management, and a Bluetooth Low Energy (BLE) sensor node. Based on temperature differences from -10 K up to 75.3 K occurring in test drives, a low power set up was chosen to achieve a system startup time below 10 minutes and to ensure service even under difficult ambient conditions, like high ambient temperatures or a slow movement of the car in stocking traffic. 2 minutes after starting the engine a power about of 10 mW is available from the chosen TEG, and in peak the power exceeds 1 W. In a 50 minute test drive it was possible to generate 650 J of energy. This information was used to develop the complete system, demonstrating the opportunity to deploy energy-autonomous wireless sensor nodes in a car, e.g. for exhaust gas monitoring. The system is used to gather sensor data, like temperature and humidity, and transmits data successfully via BLE to a prepared main node based on a Raspberry Pi. (paper)

Energy-autonomous wireless sensor nodes for automotive applications, powered by thermoelectric energy harvesting

Science.gov (United States)

Mehne, P.; Lickert, F.; Bäumker, E.; Kroener, M.; Woias, P.

2016-11-01

In this paper we will first present the measurement of temperatures on different positions at a diesel-powered car. As a result, several locations are identified as suitable to implement a wireless sensor node powered by thermal energy harvesting. Based on the data gained a thermoelectric generator (TEG) has been selected, and measurements of energy generation have been performed. Further, a complete energy-autonomous wireless sensor node was designed, including the TEG with its mounting bracket, an electronic power management, and a Bluetooth Low Energy (BLE) sensor node. Based on temperature differences from -10 K up to 75.3 K occurring in test drives, a low power set up was chosen to achieve a system startup time below 10 minutes and to ensure service even under difficult ambient conditions, like high ambient temperatures or a slow movement of the car in stocking traffic. 2 minutes after starting the engine a power about of 10 mW is available from the chosen TEG, and in peak the power exceeds 1 W. In a 50 minute test drive it was possible to generate 650 J of energy. This information was used to develop the complete system, demonstrating the opportunity to deploy energy-autonomous wireless sensor nodes in a car, e.g. for exhaust gas monitoring. The system is used to gather sensor data, like temperature and humidity, and transmits data successfully via BLE to a prepared main node based on a Raspberry Pi.

Association between lymph node size and metastasis in dogs with oral malignant melanoma: 100 cases (1987-2001).

Science.gov (United States)

Williams, Laurel E; Packer, Rebecca A

2003-05-01

To determine the association between lymph node size and metastasis and to assess measurement of lymph node size as an accurate and reliable means of tumor staging in dogs with oral malignant melanoma. Retrospective study. 100 dogs with histologically confirmed oral malignant melanoma. Clinical records for dogs with oral malignant melanoma were reviewed. Data regarding size and results of cytologic or histologic examination of lymph nodes were evaluated. The association between lymph node size and metastasis was determined. Forty-seven (47%) dogs, of which 23 (49%) had enlarged mandibular lymph nodes, had no cytologic or histologic evidence of metastasis. Of 53 (53%) dogs with cytologic or histologic evidence of mandibular lymph node metastasis, 37 (70%) had enlarged mandibular lymph nodes, and 16 (30%) had mandibular lymph nodes of normal size. Overall, 16 of the 40 (40%) dogs with normal-sized lymph nodes had microscopic evidence of metastatic disease. Sensitivity and specificity of lymph node size as a predictor of metastasis were 70 and 51%, respectively, and the positive and negative predictive values were 62 and 60%, respectively. Although a significant relationship was identified between lymph node size and metastasis to the lymph node, this association did not appear strong enough to be clinically relevant. Results suggest that lymph node size alone is insufficient for accurate clinical staging of oral malignant melanoma in dogs; cytologic or histologic examination of regional lymph nodes should routinely be performed, regardless of size of those nodes.

Effect of size of lymph node metastases on the radiation response: influence of misonidazole

International Nuclear Information System (INIS)

Courdi, A.; Malaise, E.P.

1980-01-01

Metastatic lymph nodes of EMT6 tumors growing in athymic nude mice were used at different sizes and their radiosensitivity was tested with the in vitro colony method. Following the administration of 1250 rad, the surviving fraction in air-breathing animals was found to be dependent on the size of these metastases, expressed either in weight or in cell yield per lymph node. The increasing radioresistance with increase in size was probably due to the presence of higher hypoxic fraction in big nodes (0.43 in nodes weighing more than 320 mg vs 0.10 in nodes less than 80 mg). The surviving fraction after irradiation in acutely hypoxic conditions (asphyxiated animals) or in fully oxygenated ones (in vitro) was not size dependent. Great variations were observed in the radiosensitivity of small metastatic nodes, whereas bigger metastases had a more homogeneous response. The effect of the radiosensitizer misonidazole at a dose of 0.3 mg/g was assessed on lymph node metastases of different sizes. In the presence of the drug, the survival level of big and small metastases differed by a factor of 2.2, as opposed to 4.3 in untreated metastases. This suggests that the radiosensitization is less pronounced in metastases containing a smaller hypoxic fraction

Evidence of size-selective evolution in the fighting conch from prehistoric subsistence harvesting

OpenAIRE

O'Dea, Aaron; Shaffer, Marian Lynne; Doughty, Douglas R.; Wake, Thomas A.; Rodriguez, Felix A.

2014-01-01

Intensive size-selective harvesting can drive evolution of sexual maturity at smaller body size. Conversely, prehistoric, low-intensity subsistence harvesting is not considered an effective agent of size-selective evolution. Uniting archaeological, palaeontological and contemporary material, we show that size at sexual maturity in the edible conch Strombus pugilis declined significantly from pre-human (approx. 7 ka) to prehistoric times (approx. 1 ka) and again to the present day. Size at mat...

Vascularity and grey-scale sonographic features of normal cervical lymph nodes: variations with nodal size

International Nuclear Information System (INIS)

Ying, Michael; Ahuja, Anil; Brook, Fiona; Metreweli, Constantine

2001-01-01

AIM: This study was undertaken to investigate variations in the vascularity and grey-scale sonographic features of cervical lymph nodes with their size. MATERIALS AND METHODS: High resolution grey-scale sonography and power Doppler sonography were performed in 1133 cervical nodes in 109 volunteers who had a sonographic examination of the neck. Standardized parameters were used in power Doppler sonography. RESULTS: About 90% of lymph nodes with a maximum transverse diameter greater than 5 mm showed vascularity and an echogenic hilus. Smaller nodes were less likely to show vascularity and an echogenic hilus. As the size of the lymph nodes increased, the intranodal blood flow velocity increased significantly (P 0.05). CONCLUSIONS: The findings provide a baseline for grey-scale and power Doppler sonography of normal cervical lymph nodes. Sonologists will find varying vascularity and grey-scale appearances when encountering nodes of different sizes. Ying, M. et al. (2001)

Percolation-theoretic bounds on the cache size of nodes in mobile opportunistic networks.

Science.gov (United States)

Yuan, Peiyan; Wu, Honghai; Zhao, Xiaoyan; Dong, Zhengnan

2017-07-18

The node buffer size has a large influence on the performance of Mobile Opportunistic Networks (MONs). This is mainly because each node should temporarily cache packets to deal with the intermittently connected links. In this paper, we study fundamental bounds on node buffer size below which the network system can not achieve the expected performance such as the transmission delay and packet delivery ratio. Given the condition that each link has the same probability p to be active in the next time slot when the link is inactive and q to be inactive when the link is active, there exists a critical value p c from a percolation perspective. If p > p c , the network is in the supercritical case, where we found that there is an achievable upper bound on the buffer size of nodes, independent of the inactive probability q. When p network is in the subcritical case, and there exists a closed-form solution for buffer occupation, which is independent of the size of the network.

Design and Experimental Evaluation on an Advanced Multisource Energy Harvesting System for Wireless Sensor Nodes

Directory of Open Access Journals (Sweden)

Hao Li

2014-01-01

Full Text Available An effective multisource energy harvesting system is presented as power supply for wireless sensor nodes (WSNs. The advanced system contains not only an expandable power management module including control of the charging and discharging process of the lithium polymer battery but also an energy harvesting system using the maximum power point tracking (MPPT circuit with analog driving scheme for the collection of both solar and vibration energy sources. Since the MPPT and the power management module are utilized, the system is able to effectively achieve a low power consumption. Furthermore, a super capacitor is integrated in the system so that current fluctuations of the lithium polymer battery during the charging and discharging processes can be properly reduced. In addition, through a simple analog switch circuit with low power consumption, the proposed system can successfully switch the power supply path according to the ambient energy sources and load power automatically. A practical WSNs platform shows that efficiency of the energy harvesting system can reach about 75–85% through the 24-hour environmental test, which confirms that the proposed system can be used as a long-term continuous power supply for WSNs.

A batch process micromachined thermoelectric energy harvester: fabrication and characterization

International Nuclear Information System (INIS)

Su, J; Goedbloed, M; Van Andel, Y; De Nooijer, M C; Elfrink, R; Wang, Z; Vullers, R J M; Leonov, V

2010-01-01

Micromachined thermopiles are considered as a cost-effective solution for energy harvesters working at a small temperature difference and weak heat flows typical for, e.g., the human body. They can be used for powering autonomous wireless sensor nodes in a body area network. In this paper, a micromachined thermoelectric energy harvester with 6 µm high polycrystalline silicon germanium (poly-SiGe) thermocouples fabricated on a 6 inch wafer is presented. An open circuit voltage of 1.49 V and an output power of 0.4 µW can be generated with 3.5 K temperature difference in a model of a wearable micromachined energy harvester of the discussed design, which has a die size of 1.0 mm × 2.5 mm inside a watch-size generator

Response of a tropical tree to non-timber forest products harvest and reduction in habitat size

Science.gov (United States)

Kouagou, M’Mouyohoun; Natta, Armand K.; Gado, Choukouratou

2017-01-01

Non-timber forest products (NTFPs) are widely harvested by local people for their livelihood. Harvest often takes place in human disturbed ecosystems. However, our understanding of NTFPs harvesting impacts in fragmented habitats is limited. We assessed the impacts of fruit harvest, and reduction in habitat size on the population structures of Pentadesma butyracea Sabine (Clusiaceae) across two contrasting ecological regions (dry vs. moist) in Benin. In each region, we selected three populations for each of the three fruit harvesting intensities (low, medium and high). Harvesting intensities were estimated as the proportion of fruits harvested per population. Pentadesma butyracea is found in gallery forests along rivers and streams. We used the width of gallery forests as a measure of habitat size. We found negative effects of fruit harvest on seedling and adult density but no significant effect on population size class distribution in both ecological regions. The lack of significant effect of fruit harvest on population structure may be explained by the ability of P. butyracea to compensate for the negative effect of fruit harvesting by increasing clonal reproduction. Our results suggest that using tree density and population structure to assess the ecological impacts of harvesting clonal plants should be done with caution. PMID:28850624

Response of a tropical tree to non-timber forest products harvest and reduction in habitat size.

Directory of Open Access Journals (Sweden)

Orou G Gaoue

Full Text Available Non-timber forest products (NTFPs are widely harvested by local people for their livelihood. Harvest often takes place in human disturbed ecosystems. However, our understanding of NTFPs harvesting impacts in fragmented habitats is limited. We assessed the impacts of fruit harvest, and reduction in habitat size on the population structures of Pentadesma butyracea Sabine (Clusiaceae across two contrasting ecological regions (dry vs. moist in Benin. In each region, we selected three populations for each of the three fruit harvesting intensities (low, medium and high. Harvesting intensities were estimated as the proportion of fruits harvested per population. Pentadesma butyracea is found in gallery forests along rivers and streams. We used the width of gallery forests as a measure of habitat size. We found negative effects of fruit harvest on seedling and adult density but no significant effect on population size class distribution in both ecological regions. The lack of significant effect of fruit harvest on population structure may be explained by the ability of P. butyracea to compensate for the negative effect of fruit harvesting by increasing clonal reproduction. Our results suggest that using tree density and population structure to assess the ecological impacts of harvesting clonal plants should be done with caution.

Uptake and retention of insufflated tantalum by lymph nodes

International Nuclear Information System (INIS)

Kilpper, R.W.; Bianco, A.; Gibb, F.R.; Landman, S.; Morrow, P.E.

1976-01-01

A nonsacrifice, radiographic technique is presented for evaluating the lymph node uptake of radiographically dense materials from the lungs of beagle dogs into which the material was insufflated. With tantalum as the contrast agent, lymph nodes sometimes become visible within 2 days after exposure when the insufflation resulted in radiographic ''alveolarization'' of some of the tantalum. Localization of the material within the nodes was observed in subsequent radiographs as well as persistent retention after as much as 1 year. Through the use of preinsufflation control films and tantalum foils of varying thickness, densitometric methods for determining the amount of tantalum within the lymph nodes are being investigated. Tantalum-182 is being used to follow the lung retention of the material as well as to verify estimates of burdens in harvested nodes. Preliminary lymphokinetic data are presented from experiments utilizing powders of 1 and 5 μm (mean) particle sizes

Large lymph node size harvested as prognostic factor in gastric cancer? ¿Es el diámetro ganglionar mayor un factor pronóstico en cáncer gástrico?

Directory of Open Access Journals (Sweden)

F. Espín

2010-03-01

Full Text Available Objective: knowledge regarding prognostic factors in gastric cancer is essential to decide on single patient management. We aim to establish the value of large lymph node size in order to improve perioperative approach. Material and methods: charts of one hundred and twenty-eight consecutive patients undergoing gastrectomy for resectable gastric cancer were reviewed between January 1996 and December 2005. Patients were split in two groups according to large lymph node size harvested, group I, lymph node size ≤ 10 mm and group II, lymph node size > 10 mm. Overall five-year survival related to cancer were analyzed as a main endpoint. Prognostic factors as TNM classification and degree of differentiation have been considered. Results: there were no differences regarding age and gender (67.4 vs. 64; p = 0.34 and 66,1 vs. 68,1%; p = 0.27, respectively. Nevertheless, a significant difference has been found according to T1-T2 of TNM stage (78.1 vs. 39.1% p = Objetivo: valorar el interés del diámetro del ganglio mayor extirpado como factor pronóstico en los pacientes intervenidos por cáncer gástrico, para determinar si su detección puede ser un factor de interés en el periodo preoperatorio, para indicar tratamiento neoadyuvante. Material y métodos: se analiza un registro de 128 casos consecutivos de pacientes afectos de adenocarcinoma gástrico resecable, durante un periodo de 10 años en los que en el estudio anatomopatológico se determinó el diámetro del ganglio mayor aislado. Se estudia la relación del mismo con factores pronósticos universalmente aceptados, el grado de penetración, la presencia y extensión de metástasis ganglionares y el estadio TNM, y con la supervivencia a 5 años, estudiándose dos grupos, el grupo I compuesto por aquellos enfermos con diámetro menor o igual a 10 mm, y el grupo II con diámetros superiores a 10 mm. Resultados: no se han detectado diferencias estadísticas respecto a edad y sexo (67,4 vs. 64; p

Wireless Power Transfer to Millimeter-Sized Nodes Using Airborne Ultrasound.

Science.gov (United States)

Rekhi, Angad S; Khuri-Yakub, Butrus T; Arbabian, Amin

2017-10-01

We propose the use of airborne ultrasound for wireless power transfer to mm-sized nodes, with intended application in the next generation of the Internet of Things (IoT). We show through simulation that ultrasonic power transfer can deliver 50 [Formula: see text] to a mm-sized node 0.88 m away from a ~ 50-kHz, 25-cm 2 transmitter array, with the peak pressure remaining below recommended limits in air, and with load power increasing with transmitter area. We report wireless power recovery measurements with a precharged capacitive micromachined ultrasonic transducer, demonstrating a load power of 5 [Formula: see text] at a simulated distance of 1.05 m. We present aperture efficiency, dynamic range, and bias-free operation as key metrics for the comparison of transducers meant for wireless power recovery. We also argue that long-range wireless charging at the watt level is extremely challenging with existing technology and regulations. Finally, we compare our acoustic powering system with cutting edge electromagnetically powered nodes and show that ultrasound has many advantages over RF as a vehicle for power delivery. Our work sets the foundation for further research into ultrasonic wireless power transfer for the IoT.

Harvesting Renewable Resources of Population with Size Structure and Diffusion

Directory of Open Access Journals (Sweden)

Qiang-Jun Xie

2014-01-01

Full Text Available The aim of this work is to explore the optimal exploitation way for a biological resources model incorporating individual’s size difference and spatial effects. The existence of a unique nonnegative solution to the state system is shown by means of Banach’s fixed point theorem, and the continuous dependence of the population density with the harvesting effort is given. The optimal harvesting strategy is established via normal cone and adjoint system technique. Some conditions are found to assure that there is only one optimal policy.

Dynamic Voltage-Frequency and Workload Joint Scaling Power Management for Energy Harvesting Multi-Core WSN Node SoC

Directory of Open Access Journals (Sweden)

Xiangyu Li

2017-02-01

Full Text Available This paper proposes a scheduling and power management solution for energy harvesting heterogeneous multi-core WSN node SoC such that the system continues to operate perennially and uses the harvested energy efficiently. The solution consists of a heterogeneous multi-core system oriented task scheduling algorithm and a low-complexity dynamic workload scaling and configuration optimization algorithm suitable for light-weight platforms. Moreover, considering the power consumption of most WSN applications have the characteristic of data dependent behavior, we introduce branches handling mechanism into the solution as well. The experimental result shows that the proposed algorithm can operate in real-time on a lightweight embedded processor (MSP430, and that it can make a system do more valuable works and make more than 99.9% use of the power budget.

A Wind Energy Powered Wireless Temperature Sensor Node

Directory of Open Access Journals (Sweden)

Chuang Zhang

2015-02-01

Full Text Available A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally.

Energy harvesting from organic liquids in micro-sized microbial fuel cells

KAUST Repository

Mink, J.E.; Qaisi, R.M.; Logan, B.E.; Hussain, Muhammad Mustafa

2014-01-01

Micro-sized microbial fuel cells (MFCs) are miniature energy harvesters that use bacteria to convert biomass from liquids into usable power. The key challenge is transitioning laboratory test beds into devices capable of producing high power using

Powering embedded electronics for wind turbine monitoring using multi-source energy harvesting techniques

Science.gov (United States)

Anton, S. R.; Taylor, S. G.; Raby, E. Y.; Farinholt, K. M.

2013-03-01

With a global interest in the development of clean, renewable energy, wind energy has seen steady growth over the past several years. Advances in wind turbine technology bring larger, more complex turbines and wind farms. An important issue in the development of these complex systems is the ability to monitor the state of each turbine in an effort to improve the efficiency and power generation. Wireless sensor nodes can be used to interrogate the current state and health of wind turbine structures; however, a drawback of most current wireless sensor technology is their reliance on batteries for power. Energy harvesting solutions present the ability to create autonomous power sources for small, low-power electronics through the scavenging of ambient energy; however, most conventional energy harvesting systems employ a single mode of energy conversion, and thus are highly susceptible to variations in the ambient energy. In this work, a multi-source energy harvesting system is developed to power embedded electronics for wind turbine applications in which energy can be scavenged simultaneously from several ambient energy sources. Field testing is performed on a full-size, residential scale wind turbine where both vibration and solar energy harvesting systems are utilized to power wireless sensing systems. Two wireless sensors are investigated, including the wireless impedance device (WID) sensor node, developed at Los Alamos National Laboratory (LANL), and an ultra-low power RF system-on-chip board that is the basis for an embedded wireless accelerometer node currently under development at LANL. Results indicate the ability of the multi-source harvester to successfully power both sensors.

Wireless sensor node for detection of freight train derailment

Science.gov (United States)

Costa, Andrea; Milani, Damiano; Resta, Ferruccio; Tomasini, Gisella

2016-04-01

The target of the research activity presented in this paper is to design, to realize and to test an autonomous sensor node able to measure the accelerations in correspondence of the axle box of a freight train. The final goal of the sensor is to identify the derailment conditions by observing the variations in the spectra of the box accelerations, around the frequencies associated to the wheel revolution and its multiples. The sensor node embeds an accelerometer, a microprocessor, a transmission system, a piezoelectric bimorph energy harvester and an integrated circuit for managing the power distribution to each component of the node. In particular, a mechanical filter to be applied to the node was specifically designed to increment the energy recovered by the harvester and to filter out the high frequency components of the axle-box acceleration, allowing the use of a more sensitive accelerometer. The harvesting system was setup by means of laboratory tests carried out with an electromechanical shaker and the sensor node was finally tested through field tests on freight trains.

The Role of Energy Reservoirs in Distributed Computing: Manufacturing, Implementing, and Optimizing Energy Storage in Energy-Autonomous Sensor Nodes

Science.gov (United States)

Cowell, Martin Andrew

The world already hosts more internet connected devices than people, and that ratio is only increasing. These devices seamlessly integrate with peoples lives to collect rich data and give immediate feedback about complex systems from business, health care, transportation, and security. As every aspect of global economies integrate distributed computing into their industrial systems and these systems benefit from rich datasets. Managing the power demands of these distributed computers will be paramount to ensure the continued operation of these networks, and is elegantly addressed by including local energy harvesting and storage on a per-node basis. By replacing non-rechargeable batteries with energy harvesting, wireless sensor nodes will increase their lifetimes by an order of magnitude. This work investigates the coupling of high power energy storage with energy harvesting technologies to power wireless sensor nodes; with sections covering device manufacturing, system integration, and mathematical modeling. First we consider the energy storage mechanism of supercapacitors and batteries, and identify favorable characteristics in both reservoir types. We then discuss experimental methods used to manufacture high power supercapacitors in our labs. We go on to detail the integration of our fabricated devices with collaborating labs to create functional sensor node demonstrations. With the practical knowledge gained through in-lab manufacturing and system integration, we build mathematical models to aid in device and system design. First, we model the mechanism of energy storage in porous graphene supercapacitors to aid in component architecture optimization. We then model the operation of entire sensor nodes for the purpose of optimally sizing the energy harvesting and energy reservoir components. In consideration of deploying these sensor nodes in real-world environments, we model the operation of our energy harvesting and power management systems subject to

Harvesting Energy from Vibrations of the Underlying Structure

DEFF Research Database (Denmark)

Han, Bo; Vssilaras, S; Papadias, C.B.

2013-01-01

to the long-term structural health of a building or bridge, but at the same time they can be exploited as a power source to power the wireless sensors that are monitoring this structural health. This paper presents a new energy harvesting method based on a vibration driven electromagnetic harvester. By using......The use of wireless sensors for structural health monitoring offers several advantages such as small size, easy installation and minimal intervention on existing structures. However the most significant concern about such wireless sensors is the lifetime of the system, which depends heavily...... on the type of power supply. No matter how energy efficient the operation of a battery operated sensor is, the energy of the battery will be exhausted at some point. In order to achieve a virtually unlimited lifetime, the sensor node should be able to recharge its battery in an easy way. Energy harvesting...

A Compact Energy Harvesting System for Outdoor Wireless Sensor Nodes Based on a Low-Cost In Situ Photovoltaic Panel Characterization-Modelling Unit.

Science.gov (United States)

Antolín, Diego; Medrano, Nicolás; Calvo, Belén; Martínez, Pedro A

2017-08-04

This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units-characterization and modelling-are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc. Experimental comparison to a classical pilot panel based VOC algorithm show better efficiency under the same tested conditions.

Size of cervical lymph node and metastasis in squamous cell carcinoma of the oral tongue and floor of mouth.

Science.gov (United States)

Jarungroongruangchai, Weerawut; Charoenpitakchai, Mongkol; Silpeeyodom, Tawatchai; Pruksapong, Chatchai; Burusapat, Chairat

2014-02-01

Squamous cell carcinoma (SCC) of the oral tongue and floor of mouth are the most common head and neck cancers. Regional metastasis of SCC is most likely found at the cervical lymph node. Size and characteristics of pathologically suspicious lymph nodes are related to the aggressiveness of the primary tumor: The objective of this study is to analyze the conrrelation between sizes of cervical node and metastasis in SCC of oral tongue and floor of mouth. Retrospective review was conducted firom the patient's charts between January 2008 and December 2012. Clinical, histopathology and surgical records were reviewed. Cervical lymph nodes ofSCC of oral tongue and floor of mouth were reviewed and divided into four groups depending on their size (1-5 mm, 6-9 mm, 10-30 mm and more than 30 am,). A p-value oral cavity were recorded. Sixteen patients ofSCC of the oral tongue and 15patients of SCC of the floor of mouth underwent neck dissection (641 cervical nodes). Most ofthe patients were diagnosed with stage 3 (41.94%). Extracapsular extension was found in 72.15% of SCC of oral tongue and 73.33 % of SCC ofthe floor of mouth. Size of cervical lymph nodes less than 10 mm was found to be metastasis at 9.27% and 10.82% of SCC of oral tongue and floor of mouth, respectively. Cervical node metastasis can be found in SCC of the oral tongue and floor ofmouth with clinlically negative node andsize of cervical node less than 10 mm. Here in, size of cervical node less than 10 mm was still important due to the chance for metastasis especially high grade tumors, advanced stage cancer and lymphovascular invasion.

Effect of weed patch size on seed removal by harvester ants

Directory of Open Access Journals (Sweden)

Westermann, Paula R.

2014-02-01

Full Text Available In dryland cereals in North-eastern Spain, the harvester ant, Messor barbarus L., is responsible for removal of a large proportion of the newly produced weed seeds (40-100%. The probability that seeds will be found by the ants may be influenced by weed patch size. To investigate this source of variability, 30 seed patches were created in each of three, 50 × 50 m, blocks in a cereal field after harvest, by sequentially seeding (10, 16 and 17 August 2010 with 2000 seeds m-2 of Avena sativa L.. Patch size varied from 0.25 to 9 m2. Twenty four hours after seeding, the remaining seeds were collected and seed removal rates estimated. Average seed removal rate was lowest in the smallest (78-94% and highest in the largest patches (99-100%. Differences were mainly caused by the fact that some of the smaller patches (9.7% were not found. However, when patches were found, they were exploited at equal rates (98-100%. As predicted, the probability of finding a patch increased slightly, but significantly, with increasing patch size. When a patch was found, it was almost always fully exploited, resulting in very high seed removal rates, irrespective of patch size. These results indicate that the size of the seed patch is only a minor source of variation influencing this form of biological control of weeds.

Offspring Size and Reproductive Allocation in Harvester Ants.

Science.gov (United States)

Wiernasz, Diane C; Cole, Blaine J

2018-01-01

A fundamental decision that an organism must make is how to allocate resources to offspring, with respect to both size and number. The two major theoretical approaches to this problem, optimal offspring size and optimistic brood size models, make different predictions that may be reconciled by including how offspring fitness is related to size. We extended the reasoning of Trivers and Willard (1973) to derive a general model of how parents should allocate additional resources with respect to the number of males and females produced, and among individuals of each sex, based on the fitness payoffs of each. We then predicted how harvester ant colonies should invest additional resources and tested three hypotheses derived from our model, using data from 3 years of food supplementation bracketed by 6 years without food addition. All major results were predicted by our model: food supplementation increased the number of reproductives produced. Male, but not female, size increased with food addition; the greatest increases in male size occurred in colonies that made small females. We discuss how use of a fitness landscape improves quantitative predictions about allocation decisions. When parents can invest differentially in offspring of different types, the best strategy will depend on parental state as well as the effect of investment on offspring fitness.

Diversifying the composition and structure of managed late-successional forests with harvest gaps: What is the optimal gap size?

Science.gov (United States)

Christel C. Kern; Anthony W. D’Amato; Terry F. Strong

2013-01-01

Managing forests for resilience is crucial in the face of uncertain future environmental conditions. Because harvest gap size alters the species diversity and vertical and horizontal structural heterogeneity, there may be an optimum range of gap sizes for conferring resilience to environmental uncertainty. We examined the impacts of different harvest gap sizes on...

Radio Frequency Energy Harvesting for Long Lifetime Wireless Sensor Networks

DEFF Research Database (Denmark)

Han, Bo; Nielsen, Rasmus Hjorth; Prasad, Ramjee

2014-01-01

In wireless sensor networks energy scarcity is a major concern on energy consumption, and by properly designing on the node network architecture or selecting efficient protocols of the networks, the maximum energy can be reduced significantly thereby increasing the network lifetime. However......, in most of the cases, the sensor nodes are either powered by non-replaceable batteries, or there will be a considerable replacement cost. Thus a self-rechargeable sensor node design is necessary: the sensor node should be able to harvest energy from the environment. Among the existing techniques......, harvesting energy from the radio frequency (RF) waves gives the lowest system design. Previous research on RF energy harvesting is based on the model that the radio energy is omnidirectional in the air. In this paper, a directional transmission/receiving model is proposed which can further overcome the path...

Characterization of Energy Availability in RF Energy Harvesting Networks

Directory of Open Access Journals (Sweden)

Daniela Oliveira

2016-01-01

Full Text Available The multiple nodes forming a Radio Frequency (RF Energy Harvesting Network (RF-EHN have the capability of converting received electromagnetic RF signals in energy that can be used to power a network device (the energy harvester. Traditionally the RF signals are provided by high power transmitters (e.g., base stations operating in the neighborhood of the harvesters. Admitting that the transmitters are spatially distributed according to a spatial Poisson process, we start by characterizing the distribution of the RF power received by an energy harvester node. Considering Gamma shadowing and Rayleigh fading, we show that the received RF power can be approximated by the sum of multiple Gamma distributions with different scale and shape parameters. Using the distribution of the received RF power, we derive the probability of a node having enough energy to transmit a packet after a given amount of charging time. The RF power distribution and the probability of a harvester having enough energy to transmit a packet are validated through simulation. The numerical results obtained with the proposed analysis are close to the ones obtained through simulation, which confirms the accuracy of the proposed analysis.

Impact of Clinical Salmonellosis in Veal Calves on the Recovery of Salmonella in Lymph Nodes at Harvest.

Science.gov (United States)

Muñoz-Vargas, Lohendy; Finney, Sarah K; Hutchinson, Holden; Masterson, Margaret A; Habing, Greg

2017-11-01

The objective of this study was to determine the prevalence, serotypes, antimicrobial resistance phenotypes, and pulsed-field gel electrophoresis (PFGE) patterns of Salmonella recovered in feces and mesenteric and prefemoral lymph nodes (LNs) from cohorts of calves with and without a confirmed outbreak of salmonellosis. In a prospective cohort study, 160 calves from four farms without a reported outbreak (nonoutbreak farms) were sampled at farm and harvest. In addition, harvest samples from 80 calves of two farms with a confirmed outbreak (outbreak farms) were collected. A culture protocol for Salmonella isolation was applied for all samples and recovered isolates were further characterized by serotyping, antimicrobial susceptibility testing, and PFGE. Among nonoutbreak farms, Salmonella was recovered from 0% (0/160) farm fecal samples, 3.7% (6/160) harvest fecal swabs, 21.9% (35/160) mesenteric LNs, and 0.6% (1/160) prefemoral LNs. Serotypes identified in nonoutbreak herds included Salmonella Typhimurium, Cerro, Hartford, and Newport. Most isolates (64.3%, 27/42) exhibited a unique multidrug-resistant (MDR) phenotype, including resistance to extended-spectrum cephalosporins. Salmonella prevalence in harvest fecal samples and prefemoral LNs among calves from outbreak farms was numerically higher, but not significantly different than those without an outbreak. Serotypes recovered from outbreak farms included Salmonella Heidelberg and Typhimurium, and the monophasic Salmonella Typhimurium strains 4,5,12:i:- and 4,12:i:-, which have been also reported as highly pathogenic in humans. All isolates (33/33) exhibited an MDR phenotype. Salmonella strains recovered from ill calves in two outbreaks had indistinguishable PFGE patterns, suggesting between-farm transmission. In addition, the genotype of Salmonella Heidelberg causing an outbreak among calves was recovered from three prefemoral LNs of surviving members of the cohort at harvest. Implementation of preharvest

Simultaneous energy harvesting and information processing in wireless multiple relays with multiple antennas

Science.gov (United States)

Albaaj, Azhar; Makki, S. Vahab A.; Alabkhat, Qassem; Zahedi, Abdulhamid

2017-07-01

Wireless networks suffer from battery discharging specially in cooperative communications when multiple relays have an important role but they are energy constrained. To overcome this problem, energy harvesting from radio frequency signals is applied to charge the node battery. These intermediate nodes have the ability to harvest energy from the source signal and use the energy harvested to transmit information to the destination. In fact, the node tries to harvest energy and then transmit the data to destination. Division of energy harvesting and data transmission can be done in two algorithms: time-switching-based relaying protocol and power-splitting-based relaying protocol. These two algorithms also can be applied in delay-limited and delay-tolerant transmission systems. The previous works have assumed a single relay for energy harvesting, but in this article, the proposed method is concentrated on improving the outage probability and throughput by using multiple antennas in each relay node instead of using single antenna. According to our simulation results, when using multi-antenna relays, ability of energy harvesting is increased and thus system performance will be improved to great extent. Maximum ratio combining scheme has been used when the destination chooses the best signal of relays and antennas satisfying the required signal-to-noise ratio.

Clinical and pathologic factors affecting lymph node yields in colorectal cancer.

Directory of Open Access Journals (Sweden)

Ta-Wen Hsu

Full Text Available OBJECTIVE: Lymph node yield is recommended as a benchmark of quality care in colorectal cancer. The objective of this study was to evaluate the impact of various factors upon lymph node yield and to identify independent factors associated with lymph node harvest. MATERIALS AND METHODS: The records of 162 patients with Stage I to Stage III colorectal cancers seen in one institution were reviewed. These patients underwent radical surgery as definitive therapy; high-risk patients then received adjuvant treatment. Pathologic and demographic data were recorded and analyzed. The subgroup analysis of lymph node yields was determined using a t-test and analysis of variants. Linear regression model and multivariable analysis were used to perform potential confounding and predicting variables. RESULTS: Five variables had significant association with lymph node yield after adjustment for other factors in a multiple linear regression model. These variables were: tumor size, surgical method, specimen length, and individual surgeon and pathologist. The model with these five significant variables interpreted 44.4% of the variation. CONCLUSIONS: Patients, tumor characteristics and surgical variables all influence the number of lymph nodes retrieved. Physicians are the main gatekeepers. Adequate training and optimized guidelines could greatly improve the quality of lymph node yields.

Optimal Harvesting in a Periodic Food Chain Model with Size Structures in Predators

Energy Technology Data Exchange (ETDEWEB)

Zhang, Feng-Qin, E-mail: zhafq@263.net [Yuncheng University, Department of Applied Mathematics (China); Liu, Rong [Lvliang University, Department of Mathematics (China); Chen, Yuming, E-mail: ychen@wlu.ca [Yuncheng University, Department of Applied Mathematics (China)

2017-04-15

In this paper, we investigate a periodic food chain model with harvesting, where the predators have size structures and are described by first-order partial differential equations. First, we establish the existence of a unique non-negative solution by using the Banach fixed point theorem. Then, we provide optimality conditions by means of normal cone and adjoint system. Finally, we derive the existence of an optimal strategy by means of Ekeland’s variational principle. Here the objective functional represents the net economic benefit yielded from harvesting.

High-efficiency integrated piezoelectric energy harvesting systems

Science.gov (United States)

Hande, Abhiman; Shah, Pradeep

2010-04-01

This paper describes hierarchically architectured development of an energy harvesting (EH) system that consists of micro and/or macro-scale harvesters matched to multiple components of remote wireless sensor and communication nodes. The micro-scale harvesters consist of thin-film MEMS piezoelectric cantilever arrays and power generation modules in IC-like form to allow efficient EH from vibrations. The design uses new high conversion efficiency thin-film processes combined with novel cantilever structures tuned to multiple resonant frequencies as broadband arrays. The macro-scale harvesters are used to power the collector nodes that have higher power specifications. These bulk harvesters can be integrated with efficient adaptive power management circuits that match transducer impedance and maximize power harvested from multiple scavenging sources with very low intrinsic power consumption. Texas MicroPower, Inc. is developing process based on a composition that has the highest reported energy density as compared to other commercially available bulk PZT-based sensor/actuator ceramic materials and extending it to thin-film materials and miniature conversion transducer structures. The multiform factor harvesters can be deployed for several military and commercial applications such as underground unattended sensors, sensors in oil rigs, structural health monitoring, supply chain management, and battlefield applications such as sensors on soldier apparel, equipment, and wearable electronics.

Size-dependent piezoelectric energy-harvesting analysis of micro/nano bridges subjected to random ambient excitations

Science.gov (United States)

Radgolchin, Moeen; Moeenfard, Hamid

2018-02-01

The construction of self-powered micro-electro-mechanical units by converting the mechanical energy of the systems into electrical power has attracted much attention in recent years. While power harvesting from deterministic external excitations is state of the art, it has been much more difficult to derive mathematical models for scavenging electrical energy from ambient random vibrations, due to the stochastic nature of the excitations. The current research concerns analytical modeling of micro-bridge energy harvesters based on random vibration theory. Since classical elasticity fails to accurately predict the mechanical behavior of micro-structures, strain gradient theory is employed as a powerful tool to increase the accuracy of the random vibration modeling of the micro-harvester. Equations of motion of the system in the time domain are derived using the Lagrange approach. These are then utilized to determine the frequency and impulse responses of the structure. Assuming the energy harvester to be subjected to a combination of broadband and limited-band random support motion and transverse loading, closed-form expressions for mean, mean square, correlation and spectral density of the output power are derived. The suggested formulation is further exploited to investigate the effect of the different design parameters, including the geometric properties of the structure as well as the properties of the electrical circuit on the resulting power. Furthermore, the effect of length scale parameters on the harvested energy is investigated in detail. It is observed that the predictions of classical and even simple size-dependent theories (such as couple stress) appreciably differ from the findings of strain gradient theory on the basis of random vibration. This study presents a first-time modeling of micro-scale harvesters under stochastic excitations using a size-dependent approach and can be considered as a reliable foundation for future research in the field of

Wireless Underwater Monitoring Systems Based on Energy Harvestings

Directory of Open Access Journals (Sweden)

Sea-Hee HWANGBO

2013-01-01

Full Text Available One of the important research fields for aquatic exploitation and conservation is underwater wireless sensor network. Since limited energy source for underwater nodes and devices is a main open problem, in this paper, we propose wireless underwater monitoring systems powered by energy harvester which resolves the energy constraint. The target system generates renewable energy from energy harvester and shares the energy with underwater sensor nodes. For the realization of the system, key components to be investigated are discriminated as follows: acoustic modem, actuator, smart battery charge controller, energy harvester and wireless power transfer module. By developing acoustic modem, actuator and smart battery charge controller and utilizing off-the-shelf energy harvester and wireless power transfer module, we design and implement a prototype of the system. Also, we verify the feasibility of concept of target system by conducting indoor and outdoor experiments.

Performance of a mid-sized harvester-forwarder system in integrated harvesting of sawmill, pulpwood and firewood

Directory of Open Access Journals (Sweden)

Andrei Ioan Apăfăian

2017-12-01

Full Text Available Fully mechanized timber harvesting systems are generally characterized by a high operational performance being widespread and used across many regions. Such systems are adaptable to different levels of operational integration, enabling also the recovery of energy wood, but given integration configurations affect their performance. A production study was carried out in a Norway spruce clear-cut aiming to investigate the performance of a mid-sized harvester-forwarder system in general, and the effect that fuelwood recovery from tree tops may have on its performance. Data was collected in the field during 11 days of observation using state-of-art equipment and software. Harvester’s operations were monitored using a digital camera. Data refined from 27.5 filmed hours that accounted for 1045 felled and fully processed trees was used to model and compute its performance indicators. In addition, fuel consumption data was sampled in the field. The results indicated that a delay-free cycle time consumption was affected by variables characterizing the tree size. The net production rate was estimated to about 26.5 m3 ∙ h-1, being substantially affected by supplementary tree-top processing. Forwarding operations were monitored using a handheld computer and a Global Positioning System unit. The delay-free cycle time consumption was affected by forwarding distance and the amount of loaded wood, resulting in a net production rate of about 19.2 m3 ∙ h-1. Under these circumstances, the forwarding performance matched the harvester’s outputs for an extraction distance of about 100 m, indicating that the supplementary processing of the tree-tops had no effect on the system’s productive performance in the studied conditions. Most likely, it affected the harvester’s fuel consumption given its proportion of 9% in the delay-free harvester’s cycle time. The results also indicated a mean fuel consumption of about 1.7 l ∙ m-3 for the studied harvesting

Energy neutral protocol based on hierarchical routing techniques for energy harvesting wireless sensor network

Science.gov (United States)

Muhammad, Umar B.; Ezugwu, Absalom E.; Ofem, Paulinus O.; Rajamäki, Jyri; Aderemi, Adewumi O.

2017-06-01

Recently, researchers in the field of wireless sensor networks have resorted to energy harvesting techniques that allows energy to be harvested from the ambient environment to power sensor nodes. Using such Energy harvesting techniques together with proper routing protocols, an Energy Neutral state can be achieved so that sensor nodes can run perpetually. In this paper, we propose an Energy Neutral LEACH routing protocol which is an extension to the traditional LEACH protocol. The goal of the proposed protocol is to use Gateway node in each cluster so as to reduce the data transmission ranges of cluster head nodes. Simulation results show that the proposed routing protocol achieves a higher throughput and ensure the energy neutral status of the entire network.

Micro-scale piezoelectric vibration energy harvesting: From fixed-frequency to adaptable-frequency devices

Science.gov (United States)

Miller, Lindsay Margaret

Wireless sensor networks (WSNs) have the potential to transform engineering infrastructure, manufacturing, and building controls by allowing condition monitoring, asset tracking, demand response, and other intelligent feedback systems. A wireless sensor node consists of a power supply, sensor(s), power conditioning circuitry, radio transmitter and/or receiver, and a micro controller. Such sensor nodes are used for collecting and communicating data regarding the state of a machine, system, or process. The increasing demand for better ways to power wireless devices and increase operation time on a single battery charge drives an interest in energy harvesting research. Today, wireless sensor nodes are typically powered by a standard single-charge battery, which becomes depleted within a relatively short timeframe depending on the application. This introduces tremendous labor costs associated with battery replacement, especially when there are thousands of nodes in a network, the nodes are remotely located, or widely-distributed. Piezoelectric vibration energy harvesting presents a potential solution to the problems associated with too-short battery life and high maintenance requirements, especially in industrial environments where vibrations are ubiquitous. Energy harvester designs typically use the harvester to trickle charge a rechargeable energy storage device rather than directly powering the electronics with the harvested energy. This allows a buffer between the energy harvester supply and the load where energy can be stored in a "tank". Therefore, the harvester does not need to produce the full required power at every instant to successfully power the node. In general, there are tens of microwatts of power available to be harvested from ambient vibrations using micro scale devices and tens of milliwatts available from ambient vibrations using meso scale devices. Given that the power requirements of wireless sensor nodes range from several microwatts to about one

Improving CT detection sensitivity for nodal metastases in oesophageal cancer with combination of smaller size and lymph node axial ratio

Energy Technology Data Exchange (ETDEWEB)

Liu, Jianfang [Chinese Academy of Medical Sciences and Peking Union Medical College, National Cancer Center/Cancer Hospital, Beijing (China); Capital Medical University Electric Power Teaching Hospital, Beijing (China); Wang, Zhu; Qu, Dong; Yao, Libo [Chinese Academy of Medical Sciences and Peking Union Medical College, National Cancer Center/Cancer Hospital, Beijing (China); Shao, Huafei [Affiliated Yantai Yuhuangding Hospital of Qingdao University Medical College, Yantai (China); Liu, Jian [Meitan General Hospital, Beijing (China)

2018-01-15

To investigate the value of CT with inclusion of smaller lymph node (LN) sizes and axial ratio to improve the sensitivity in diagnosis of regional lymph node metastases in oesophageal squamous cell carcinoma (OSCC). The contrast-enhanced multidetector row spiral CT (MDCT) multiplanar reconstruction images of 204 patients with OSCC were retrospectively analysed. The long-axis and short-axis diameters of the regional LNs were measured and axial ratios were calculated (short-axis/long-axis diameters). Nodes were considered round if the axial ratio exceeded the optimal LN axial ratio, which was determined by receiver operating characteristic analysis. A positive predictive value (PPV) exceeding 50% is needed. This was achieved only with LNs larger than 9 mm in short-axis diameter, but nodes of this size were rare (sensitivity 37.3%, specificity 96.4%, accuracy 85.8%). If those round nodes (axial ratio exceeding 0.66) between 7 mm and 9 mm in size were considered metastases as well, it might improve the sensitivity to 67.2% with a PPV of 63.9% (specificity 91.6%, accuracy 87.2%). Combination of a smaller size and axial ratio for LNs in MDCT as criteria improves the detection sensitivity for LN metastases in OSCC. (orig.)

Energy Harvesting Wireless Sensor Networks: From Characterization to Duty Cycle Dimensioning

OpenAIRE

Oueis , Jad; Stanica , Razvan; Valois , Fabrice

2016-01-01

International audience; Energy harvesting capabilities are challenging our understanding of wireless sensor networks by adding recharging capacity to sensor nodes. This has a significant impact on the communication paradigm, as networking mechanisms can benefit from these potentially infinite renewable energy sources. In this work, we study the consequences of implementing photovoltaic energy harvesting on the duty cycle of a wireless sensor node, in both outdoor and indoor scenarios. We show...

Operating Wireless Sensor Nodes without Energy Storage: Experimental Results with Transient Computing

Directory of Open Access Journals (Sweden)

Faisal Ahmed

2016-12-01

Full Text Available Energy harvesting is increasingly used for powering wireless sensor network nodes. Recently, it has been suggested to combine it with the concept of transient computing whereby the wireless sensor nodes operate without energy storage capabilities. This new combined approach brings benefits, for instance ultra-low power nodes and reduced maintenance, but also raises new challenges, foremost dealing with nodes that may be left without power for various time periods. Although transient computing has been demonstrated on microcontrollers, reports on experiments with wireless sensor nodes are still scarce in the literature. In this paper, we describe our experiments with solar, thermal, and RF energy harvesting sources that are used to power sensor nodes (including wireless ones without energy storage, but with transient computing capabilities. The results show that the selected solar and thermal energy sources can operate both the wired and wireless nodes without energy storage, whereas in our specific implementation, the developed RF energy source can only be used for the selected nodes without wireless connectivity.

Security challenges for energy-harvesting wireless sensor networks

DEFF Research Database (Denmark)

Di Mauro, Alessio; Papini, Davide; Dragoni, Nicola

2012-01-01

With the recent introduction of Energy-Harvesting nodes, security is gaining more and more importance in sensor networks. By exploiting the ability of scavenging energy from the surrounding environment, the lifespan of a node has drastically increased. This is one of the reason why security needs...

Quantifying the effect of colony size and food distribution on harvester ant foraging.

Directory of Open Access Journals (Sweden)

Tatiana P Flanagan

Full Text Available Desert seed-harvester ants, genus Pogonomyrmex, are central place foragers that search for resources collectively. We quantify how seed harvesters exploit the spatial distribution of seeds to improve their rate of seed collection. We find that foraging rates are significantly influenced by the clumpiness of experimental seed baits. Colonies collected seeds from larger piles faster than randomly distributed seeds. We developed a method to compare foraging rates on clumped versus random seeds across three Pogonomyrmex species that differ substantially in forager population size. The increase in foraging rate when food was clumped in larger piles was indistinguishable across the three species, suggesting that species with larger colonies are no better than species with smaller colonies at collecting clumped seeds. These findings contradict the theoretical expectation that larger groups are more efficient at exploiting clumped resources, thus contributing to our understanding of the importance of the spatial distribution of food sources and colony size for communication and organization in social insects.

Finite size effects and symmetry breaking in the evolution of networks of competing Boolean nodes

International Nuclear Information System (INIS)

Liu, M; Bassler, K E

2011-01-01

Finite size effects on the evolutionary dynamics of Boolean networks are analyzed. In the model considered, Boolean networks evolve via a competition between nodes that punishes those in the majority. Previous studies have found that large networks evolve to a statistical steady state that is both critical and highly canalized, and that the evolution of canalization, which is a form of robustness found in genetic regulatory networks, is associated with a particular symmetry of the evolutionary dynamics. Here, it is found that finite size networks evolve in a fundamentally different way than infinitely large networks do. The symmetry of the evolutionary dynamics of infinitely large networks that selects for canalizing Boolean functions is broken in the evolutionary dynamics of finite size networks. In finite size networks, there is an additional selection for input-inverting Boolean functions that output a value opposite to the majority of input values. The reason for the symmetry breaking in the evolutionary dynamics is found to be due to the need for nodes in finite size networks to behave differently in order to cooperate so that the system collectively performs as efficiently as possible. The results suggest that both finite size effects and symmetry are fundamental for understanding the evolution of real-world complex networks, including genetic regulatory networks.

Energy harvesting from hydraulic pressure fluctuations

International Nuclear Information System (INIS)

Cunefare, K A; Skow, E A; Erturk, A; Savor, J; Verma, N; Cacan, M R

2013-01-01

State-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring to avoid catastrophic failures. Energy harvesting in hydraulic systems could enable self-powered wireless sensor nodes for applications such as energy-autonomous structural health monitoring and prognosis. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is the dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. The prototype employed an axially-poled off-the-shelf piezoelectric stack. A housing isolated the stack from the hydraulic fluid while maintaining a mechanical coupling allowing for dynamic-pressure-induced deflection of the stack. The prototype exhibited an off-resonance energy harvesting problem since the fundamental resonance of the piezoelectric stack was much higher than the frequency content of the pressure ripple. The prototype was designed to provide a suitable power output for powering sensors with a maximum output of 1.2 mW. This work also presents electromechanical model simulations and experimental characterization of the piezoelectric power output from the pressure ripple in terms of the force transmitted into the harvester. (paper)

Chemical shift effect predicting lymph node status in rectal cancer using high-resolution MR imaging with node-for-node matched histopathological validation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hongmei; Zhang, Chongda; Ye, Feng; Liu, Yuan; Zhou, Chunwu [Chinese Academy of Medical Sciences and Peking Union Medical College, Department of Diagnostic Radiology, National Cancer Center/Cancer Hospital, ChaoYang District, Beijing (China); Zheng, Zhaoxu [Chinese Academy of Medical Sciences and Peking Union Medical College, Department of Colorectal Oncology, National Cancer Center/Cancer Hospital, ChaoYang District, Beijing (China); Zou, Shuangmei [Chinese Academy of Medical Sciences and Peking Union Medical College, Department of Pathology, National Cancer Center/Cancer Hospital, ChaoYang District, Beijing (China)

2017-09-15

To evaluate the value of the chemical shift effect (CSE) as well as other criteria for the prediction of lymph node status. Twenty-nine patients who underwent radical surgery of rectal cancers were studied with pre- and postoperative specimen MRI. Lymph nodes were harvested from transverse whole-mount specimens and compared with in vivo and ex vivo images to obtain a precise slice-for-section match. Preoperative MR characteristics including CSE, as well as other predictors, were evaluated by two readers independently between benign and metastatic nodes. A total of 255 benign and 35 metastatic nodes were obtained; 71.4% and 69.4% of benign nodes were detected with regular CSE for two readers, whereas 80.0% and 74.3% of metastatic nodes with absence of CSE. The CSE rendered areas under the ROC curve (AUC) of 0.879 and 0.845 for predicting nodal status for two readers. The criteria of nodal location, border, signal intensity and minimum distance to the rectal wall were also useful but with AUCs (0.629-0.743) lower than those of CSE. CSE is a reliable predictor for differentiating benign from metastatic nodes. Additional criteria should be taken into account when it is difficult to determine the nodal status by using only a single predictor. (orig.)

[Application of subserosal injection of carbon nanoparticles via infusion needle to label lymph nodes in laparoscopic radical gastrectomy].

Science.gov (United States)

Chen, Hongyuan; Wang, Yanan; Xue, Fangqin; Yu, Jiang; Hu, Yanfeng; Liu, Hao; Yan, Jun; Li, Guoxin

2014-05-01

To explore the feasibility of subserosal injection of carbon nanoparticle via venous infusion needle to label lymph node and its application value in laparoscopic radical gastrectomy. Forty patients with gastric cancer were randomly divided into two groups (carbon nanoparticle group and control group). Subserosal injection of carbon nanoparticle around the tumor was performed via venous infusion needle laparoscopically at the beginning of surgery in carbon nanoparticles group, while the patients routinely underwent laparoscopic radical gastrectomy in control group. Results of harvested lymph nodes were compared between the two groups. The perioperative complications and the side effect of carbon nanoparticle were also evaluated. The average number of harvested lymph node in carbon nanoparticle group (31.7±7.6) was significantly higher than that in control group (19.8±6.1, Pinjection of carbon nanoparticle via venous infusion needle to label lymph nodes during laparoscopic radical gastrectomy is safe and feasible. It can increase the number of harvested lymph node, especially the small node.

Can axial-based nodal size criteria be used in other imaging planes to accurately determine "enlarged" head and neck lymph nodes?

Science.gov (United States)

Bartlett, Eric S; Walters, Thomas D; Yu, Eugene

2013-01-01

Objective. We evaluate if axial-based lymph node size criteria can be applied to coronal and sagittal planes. Methods. Fifty pretreatment computed tomographic (CT) neck exams were evaluated in patients with head and neck squamous cell carcinoma (SCCa) and neck lymphadenopathy. Axial-based size criteria were applied to all 3 imaging planes, measured, and classified as "enlarged" if equal to or exceeding size criteria. Results. 222 lymph nodes were "enlarged" in one imaging plane; however, 53.2% (118/222) of these were "enlarged" in all 3 planes. Classification concordance between axial versus coronal/sagittal planes was poor (kappa = -0.09 and -0.07, resp., P planes. Conclusion. Classification of "enlarged" lymph nodes differs between axial versus coronal/sagittal imaging planes when axial-based nodal size criteria are applied independently to all three imaging planes, and exclusively used without other morphologic nodal data.

Adaptive Multipath Key Reinforcement for Energy Harvesting Wireless Sensor Networks

DEFF Research Database (Denmark)

Di Mauro, Alessio; Dragoni, Nicola

2015-01-01

Energy Harvesting - Wireless Sensor Networks (EH-WSNs) constitute systems of networked sensing nodes that are capable of extracting energy from the environment and that use the harvested energy to operate in a sustainable state. Sustainability, seen as design goal, has a significant impact...

Energy Harvesting Chip and the Chip Based Power Supply Development for a Wireless Sensor Network.

Science.gov (United States)

Lee, Dasheng

2008-12-02

In this study, an energy harvesting chip was developed to scavenge energy from artificial light to charge a wireless sensor node. The chip core is a miniature transformer with a nano-ferrofluid magnetic core. The chip embedded transformer can convert harvested energy from its solar cell to variable voltage output for driving multiple loads. This chip system yields a simple, small, and more importantly, a battery-less power supply solution. The sensor node is equipped with multiple sensors that can be enabled by the energy harvesting power supply to collect information about the human body comfort degree. Compared with lab instruments, the nodes with temperature, humidity and photosensors driven by harvested energy had variation coefficient measurement precision of less than 6% deviation under low environmental light of 240 lux. The thermal comfort was affected by the air speed. A flow sensor equipped on the sensor node was used to detect airflow speed. Due to its high power consumption, this sensor node provided 15% less accuracy than the instruments, but it still can meet the requirement of analysis for predicted mean votes (PMV) measurement. The energy harvesting wireless sensor network (WSN) was deployed in a 24-hour convenience store to detect thermal comfort degree from the air conditioning control. During one year operation, the sensor network powered by the energy harvesting chip retained normal functions to collect the PMV index of the store. According to the one month statistics of communication status, the packet loss rate (PLR) is 2.3%, which is as good as the presented results of those WSNs powered by battery. Referring to the electric power records, almost 54% energy can be saved by the feedback control of an energy harvesting sensor network. These results illustrate that, scavenging energy not only creates a reliable power source for electronic devices, such as wireless sensor nodes, but can also be an energy source by building an energy efficient

Energy Harvesting Chip and the Chip Based Power Supply Development for a Wireless Sensor Network

Science.gov (United States)

Lee, Dasheng

2008-01-01

In this study, an energy harvesting chip was developed to scavenge energy from artificial light to charge a wireless sensor node. The chip core is a miniature transformer with a nano-ferrofluid magnetic core. The chip embedded transformer can convert harvested energy from its solar cell to variable voltage output for driving multiple loads. This chip system yields a simple, small, and more importantly, a battery-less power supply solution. The sensor node is equipped with multiple sensors that can be enabled by the energy harvesting power supply to collect information about the human body comfort degree. Compared with lab instruments, the nodes with temperature, humidity and photosensors driven by harvested energy had variation coefficient measurement precision of less than 6% deviation under low environmental light of 240 lux. The thermal comfort was affected by the air speed. A flow sensor equipped on the sensor node was used to detect airflow speed. Due to its high power consumption, this sensor node provided 15% less accuracy than the instruments, but it still can meet the requirement of analysis for predicted mean votes (PMV) measurement. The energy harvesting wireless sensor network (WSN) was deployed in a 24-hour convenience store to detect thermal comfort degree from the air conditioning control. During one year operation, the sensor network powered by the energy harvesting chip retained normal functions to collect the PMV index of the store. According to the one month statistics of communication status, the packet loss rate (PLR) is 2.3%, which is as good as the presented results of those WSNs powered by battery. Referring to the electric power records, almost 54% energy can be saved by the feedback control of an energy harvesting sensor network. These results illustrate that, scavenging energy not only creates a reliable power source for electronic devices, such as wireless sensor nodes, but can also be an energy source by building an energy efficient

Energy Harvesting Chip and the Chip Based Power Supply Development for a Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Dasheng Lee

2008-12-01

Full Text Available In this study, an energy harvesting chip was developed to scavenge energy from artificial light to charge a wireless sensor node. The chip core is a miniature transformer with a nano-ferrofluid magnetic core. The chip embedded transformer can convert harvested energy from its solar cell to variable voltage output for driving multiple loads. This chip system yields a simple, small, and more importantly, a battery-less power supply solution. The sensor node is equipped with multiple sensors that can be enabled by the energy harvesting power supply to collect information about the human body comfort degree. Compared with lab instruments, the nodes with temperature, humidity and photosensors driven by harvested energy had variation coefficient measurement precision of less than 6% deviation under low environmental light of 240 lux. The thermal comfort was affected by the air speed. A flow sensor equipped on the sensor node was used to detect airflow speed. Due to its high power consumption, this sensor node provided 15% less accuracy than the instruments, but it still can meet the requirement of analysis for predicted mean votes (PMV measurement. The energy harvesting wireless sensor network (WSN was deployed in a 24-hour convenience store to detect thermal comfort degree from the air conditioning control. During one year operation, the sensor network powered by the energy harvesting chip retained normal functions to collect the PMV index of the store. According to the one month statistics of communication status, the packet loss rate (PLR is 2.3%, which is as good as the presented results of those WSNs powered by battery. Referring to the electric power records, almost 54% energy can be saved by the feedback control of an energy harvesting sensor network. These results illustrate that, scavenging energy not only creates a reliable power source for electronic devices, such as wireless sensor nodes, but can also be an energy source by building an

La-CTP: Loop-Aware Routing for Energy-Harvesting Wireless Sensor Networks.

Science.gov (United States)

Sun, Guodong; Shang, Xinna; Zuo, Yan

2018-02-02

In emerging energy-harvesting wireless sensor networks (EH-WSN), the sensor nodes can harvest environmental energy to drive their operation, releasing the user's burden in terms of frequent battery replacement, and even enabling perpetual sensing systems. In EH-WSN applications, usually, the node in energy-harvesting or recharging state has to stop working until it completes the energy replenishment. However, such temporary departures of recharging nodes severely impact the packet routing, and one immediate result is the routing loop problem. Controlling loops in connectivity-intermittent EH-WSN in an efficient way is a big challenge in practice, and so far, users still lack of effective and practicable routing protocols with loop handling. Based on the Collection Tree Protocol (CTP) widely used in traditional wireless sensor networks, this paper proposes a loop-aware routing protocol for real-world EH-WSNs, called La-CTP, which involves a new parent updating metric and a proactive, adaptive beaconing scheme to effectively suppress the occurrence of loops and unlock unavoidable loops, respectively. We constructed a 100-node testbed to evaluate La-CTP, and the experimental results showed its efficacy and efficiency.

Design of a bimorph piezoelectric energy harvester for railway monitoring

Energy Technology Data Exchange (ETDEWEB)

Li, Jingcheng; Jang, Shinae; Tang, Jiong [Univ. of Connecticut, Connecticut (United States)

2012-12-15

Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s{sup 2} base excitation compared to stand alone piezoelectric energy harvester without tip mass.

Design of a bimorph piezoelectric energy harvester for railway monitoring

International Nuclear Information System (INIS)

Li, Jingcheng; Jang, Shinae; Tang, Jiong

2012-01-01

Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s 2 base excitation compared to stand alone piezoelectric energy harvester without tip mass

Wireless Energy Harvesting Two-Way Relay Networks with Hardware Impairments.

Science.gov (United States)

Peng, Chunling; Li, Fangwei; Liu, Huaping

2017-11-13

This paper considers a wireless energy harvesting two-way relay (TWR) network where the relay has energy-harvesting abilities and the effects of practical hardware impairments are taken into consideration. In particular, power splitting (PS) receiver is adopted at relay to harvests the power it needs for relaying the information between the source nodes from the signals transmitted by the source nodes, and hardware impairments is assumed suffered by each node. We analyze the effect of hardware impairments [-20]on both decode-and-forward (DF) relaying and amplify-and-forward (AF) relaying networks. By utilizing the obtained new expressions of signal-to-noise-plus-distortion ratios, the exact analytical expressions of the achievable sum rate and ergodic capacities for both DF and AF relaying protocols are derived. Additionally, the optimal power splitting (OPS) ratio that maximizes the instantaneous achievable sum rate is formulated and solved for both protocols. The performances of DF and AF protocols are evaluated via numerical results, which also show the effects of various network parameters on the system performance and on the OPS ratio design.

Outage Probability Analysis in Power-Beacon Assisted Energy Harvesting Cognitive Relay Wireless Networks

Directory of Open Access Journals (Sweden)

Ngoc Phuc Le

2017-01-01

Full Text Available We study the performance of the secondary relay system in a power-beacon (PB assisted energy harvesting cognitive relay wireless network. In our system model, a secondary source node and a relay node first harvest energy from distributed PBs. Then, the source node transmits its data to the destination node with the help of the relay node. Also, fading coefficients of the links from the PBs to the source node and relay node are assumed independent but not necessarily identically distributed (i.n.i.d Nakagami-m random variables. We derive exact expressions for the power outage probability and the channel outage probability. Based on that, we analyze the total outage probability of the secondary relay system. Asymptotic analysis is also performed, which provides insights into the system behavior. Moreover, we evaluate impacts of the primary network on the performance of the secondary network with respect to the tolerant interference threshold at the primary receiver as well as the interference introduced by the primary transmitter at the secondary source and relay nodes. Simulation results are provided to validate the analysis.

Energy harvesting for wireless sensors by using piezoelectric transducers

Energy Technology Data Exchange (ETDEWEB)

Duerager, Christian [Empa, Swiss Federal Laboratories for Materials Science and Technology, Duebendorf (Switzerland)

2012-07-01

Wireless sensor technology, which integrates transducers, measurement electronics and wireless communication, has become increasingly vital in structural health monitoring (SHM) applications. Compared to traditional wired systems, wireless solutions reduce the installation time and costs and are not subjected to breakage caused by harsh weather conditions or other extreme events. Because of the low installation costs, wireless sensor networks allow the deployment of a big number of wireless sensor nodes on the structures. Moreover, the nodes can be placed on particularly critical components of the structure difficult to reach by wires. In most of the cases the power supply are conventional batteries, which could be a problem because of their finite life span. Furthermore, in the case of wireless sensor nodes located on structures, it is often advantageous to embed them, which makes an access impossible. Therefore, if a method of obtaining the untapped energy surrounding these sensors was implemented, significant life could be added to the power supply. Various approaches to energy harvesting and energy storage are discussed and limitations associated with the current technology are addressed. In this paper we first discuss the research that has been performed in the area of energy harvesting for wireless sensor technologies by using the ambient vibration energy. In many cases the energy produced by the ambient vibrations is far too small to directly power a wireless sensor node. Therefore, in a second step we discuss the development process for an electronic energy harvesting circuit optimized for piezoelectric transducers. In the last part of this paper an experiment with different piezoelectric transducers and their applicability for energy harvesting applications on vibrating structures will be discussed. (orig.)

A Hybrid Indoor Ambient Light and Vibration Energy Harvester for Wireless Sensor Nodes

Directory of Open Access Journals (Sweden)

Hua Yu

2014-05-01

Full Text Available To take advantage of applications where both light and vibration energy are available, a hybrid indoor ambient light and vibration energy harvesting scheme is proposed in this paper. This scheme uses only one power conditioning circuit to condition the combined output power harvested from both energy sources so as to reduce the power dissipation. In order to more accurately predict the instantaneous power harvested from the solar panel, an improved five-parameter model for small-scale solar panel applying in low light illumination is presented. The output voltage is increased by using the MEMS piezoelectric cantilever arrays architecture. It overcomes the disadvantage of traditional MEMS vibration energy harvester with low voltage output. The implementation of the maximum power point tracking (MPPT for indoor ambient light is implemented using analog discrete components, which improves the whole harvester efficiency significantly compared to the digital signal processor. The output power of the vibration energy harvester is improved by using the impedance matching technique. An efficient mechanism of energy accumulation and bleed-off is also discussed. Experiment results obtained from an amorphous-silicon (a-Si solar panel of 4.8 × 2.0 cm2 and a fabricated piezoelectric MEMS generator of 11 × 12.4 mm2 show that the hybrid energy harvester achieves a maximum efficiency around 76.7%.

Autonomous solutions for powering wireless sensor nodes in rivers

Science.gov (United States)

Kamenar, E.; Maćešić, S.; Gregov, G.; Blažević, D.; Zelenika, S.; Marković, K.; Glažar, V.

2015-05-01

There is an evident need for monitoring pollutants and/or other conditions in river flows via wireless sensor networks. In a typical wireless sensor network topography, a series of sensor nodes is to be deployed in the environment, all wirelessly connected to each other and/or their gateways. Each sensor node is composed of active electronic devices that have to be constantly powered. In general, batteries can be used for this purpose, but problems may occur when they have to be replaced. In the case of large networks, when sensor nodes can be placed in hardly accessible locations, energy harvesting can thus be a viable powering solution. The possibility to use three different small-scale river flow energy harvesting principles is hence thoroughly studied in this work: a miniaturized underwater turbine, a so-called `piezoelectric eel' and a hybrid turbine solution coupled with a rigid piezoelectric beam. The first two concepts are then validated experimentally in laboratory as well as in real river conditions. The concept of the miniaturised hydro-generator is finally embedded into the actual wireless sensor node system and its functionality is confirmed.

EANM practice guidelines for lymphoscintigraphy and sentinel lymph node biopsy in melanoma

DEFF Research Database (Denmark)

Bluemel, Christina; Herrmann, Ken; Giammarile, Francesco

2015-01-01

PURPOSE: Sentinel lymph node biopsy is an essential staging tool in patients with clinically localized melanoma. The harvesting of a sentinel lymph node entails a sequence of procedures with participation of specialists in nuclear medicine, radiology, surgery and pathology. The aim of this docume...

Can Axial-Based Nodal Size Criteria Be Used in Other Imaging Planes to Accurately Determine “Enlarged” Head and Neck Lymph Nodes?

Science.gov (United States)

Bartlett, Eric S.; Walters, Thomas D.; Yu, Eugene

2013-01-01

Objective. We evaluate if axial-based lymph node size criteria can be applied to coronal and sagittal planes. Methods. Fifty pretreatment computed tomographic (CT) neck exams were evaluated in patients with head and neck squamous cell carcinoma (SCCa) and neck lymphadenopathy. Axial-based size criteria were applied to all 3 imaging planes, measured, and classified as “enlarged” if equal to or exceeding size criteria. Results. 222 lymph nodes were “enlarged” in one imaging plane; however, 53.2% (118/222) of these were “enlarged” in all 3 planes. Classification concordance between axial versus coronal/sagittal planes was poor (kappa = −0.09 and −0.07, resp., P planes. Conclusion. Classification of “enlarged” lymph nodes differs between axial versus coronal/sagittal imaging planes when axial-based nodal size criteria are applied independently to all three imaging planes, and exclusively used without other morphologic nodal data. PMID:23984099

Review of Energy Harvesters Utilizing Bridge Vibrations

Directory of Open Access Journals (Sweden)

Farid Ullah Khan

2016-01-01

Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

State of the art in acoustic energy harvesting

Science.gov (United States)

Ullah Khan, Farid; Izhar

2015-02-01

For portable and embedded smart, wireless electronic systems, energy harvesting from the ambient energy sources has gained immense interest in recent years. Several ambient energies exist in the environment of wireless sensor nodes (WSNs) that include thermal, solar, vibration and acoustic energy. This paper presents the recent development in the field of acoustic energy harvesters (AEHs). AEHs convert the acoustic energy into useful electrical energy for the operation of autonomous wireless sensors. Mainly, two types of AEHs (electromagnetic and piezoelectric based) have been developed and reported in literature. The power produced by the reported piezoelectric AEHs ranges from 0.68 pW to 30 mW however, the power generation of the developed electromagnetic AEHs is in the range of 1.5-1.96 mW. The overall size of most of the developed piezoelectric and electromagnetic AEHs are quite comparable and in millimeter scale. The resonant frequencies of electromagnetic AEHs are on the lower side (143-470 Hz), than that of piezoelectric AEHs (146 Hz-16.7 kHz).

State of the art in acoustic energy harvesting

International Nuclear Information System (INIS)

Khan, Farid Ullah; Izhar

2015-01-01

For portable and embedded smart, wireless electronic systems, energy harvesting from the ambient energy sources has gained immense interest in recent years. Several ambient energies exist in the environment of wireless sensor nodes (WSNs) that include thermal, solar, vibration and acoustic energy. This paper presents the recent development in the field of acoustic energy harvesters (AEHs). AEHs convert the acoustic energy into useful electrical energy for the operation of autonomous wireless sensors. Mainly, two types of AEHs (electromagnetic and piezoelectric based) have been developed and reported in literature. The power produced by the reported piezoelectric AEHs ranges from 0.68 pW to 30 mW; however, the power generation of the developed electromagnetic AEHs is in the range of 1.5–1.96 mW. The overall size of most of the developed piezoelectric and electromagnetic AEHs are quite comparable and in millimeter scale. The resonant frequencies of electromagnetic AEHs are on the lower side (143–470 Hz), than that of piezoelectric AEHs (146 Hz–16.7 kHz). (topical review)

Leveraging Energy Harvesting and Wake-Up Receivers for Long-Term Wireless Sensor Networks.

Science.gov (United States)

Ait Aoudia, Fayçal; Gautier, Matthieu; Magno, Michele; Berder, Olivier; Benini, Luca

2018-05-15

Wireless sensor nodes are traditionally powered by individual batteries, and a significant effort has been devoted to maximizing the lifetime of these devices. However, as the batteries can only store a finite amount of energy, the network is still doomed to die, and changing the batteries is not always possible. A promising solution is to enable each node to harvest energy directly in its environment, using individual energy harvesters. Moreover, novel ultra-low power wake-up receivers, which allow continuous listening of the channel with negligible power consumption, are emerging. These devices enable asynchronous communication, further reducing the power consumption related to communication, which is typically one the most energy-consuming tasks in wireless sensor networks. Energy harvesting and wake-up receivers can be combined to significantly increase the energy efficiency of sensor networks. In this paper, we propose an energy manager for energy harvesting wireless sensor nodes and an asynchronous medium access control protocol, which exploits ultra-low power wake-up receivers. The two components are designed to work together and especially to fit the stringent constraints of wireless sensor nodes. The proposed approach has been implemented on a real hardware platform and tested in the field. Experimental results demonstrate the benefits of the proposed approach in terms of energy efficiency, power consumption and throughput, which can be up to more than two-times higher compared to traditional schemes.

[Application of lymph node labeling with carbon nanoparticles by preoperative endoscopic subserosal injection in laparoscopic radical gastrectomy].

Science.gov (United States)

Hong, Q; Wang, Y; Wang, J J; Hu, C G; Fang, Y J; Fan, X X; Liu, T; Tong, Q

2017-01-10

Objective: To evaluate the application value of carbon lymph node tracing technique by preoperative endoscopic subserosal injection in laparoscopic radical gastrectomy. Methods: From June 2013 to February 2015, seventy eight patients with gastric cancer were enrolled and randomly divided into trial group and control group. Subserosal injection of carbon nanoparticles around the tumor was performed by preoperative endoscopic subserosal injection one day before the operation in trial group, while the patients routinely underwent laparoscopic gastrectomy in control group. Results of harvested lymph nodes, postoperative complications were compared between the two groups. Carbon nanoparticle-related side effect was also evaluated. Results: The average number of harvested lymph node in trial group was significantly higher than that in control group (35.5±8.5 vs 29.5±6.5, P 0.05), and no carbon nanoparticle-related side effect was observed. Conclusion: Given a higher harvested lymph node number and a similar rate of complications, preoperative endoscopic subserosal injection of carbon nanoparticles was safe and feasible.

Energy Harvesting - Wireless Sensor Networks for Indoors Applications Using IEEE 802.11

DEFF Research Database (Denmark)

Fafoutis, Xenofon; Sørensen, Thomas; Madsen, Jan

2014-01-01

The paper investigates the feasibility of using IEEE 802.11 in energy harvesting low-power sensing applications. The investigation is based on a prototype carbon dioxide sensor node that is powered by artificial indoors light. The wireless communication module of the sensor node is based on the RTX......4100 module. RTX4100 incorporates a wireless protocol that duty-cycles the radio while being compatible with IEEE 802.11 access points. The presented experiments demonstrate sustainable operation but indicate a trade-off between the benefits of using IEEE 802.11 in energy harvesting applications...

Analytical Comparison of MAC Schemes for Energy Harvesting - Wireless Sensor Networks

DEFF Research Database (Denmark)

Fafoutis, Xenofon; Dragoni, Nicola

2012-01-01

the suitability of the three paradigms in the context of Energy Harvesting — Wireless Sensor Networks (EH-WSNs) in which nodes are powered by energy that they harvest from their surrounding environment. The two suitable paradigms are modeled and compared to each other. The analysis indicates the specific...

Genetic parameters for uniformity of harvest weight and body size traits in the GIFT strain of Nile tilapia.

Science.gov (United States)

Marjanovic, Jovana; Mulder, Han A; Khaw, Hooi L; Bijma, Piter

2016-06-10

Animal breeding programs have been very successful in improving the mean levels of traits through selection. However, in recent decades, reducing the variability of trait levels between individuals has become a highly desirable objective. Reaching this objective through genetic selection requires that there is genetic variation in the variability of trait levels, a phenomenon known as genetic heterogeneity of environmental (residual) variance. The aim of our study was to investigate the potential for genetic improvement of uniformity of harvest weight and body size traits (length, depth, and width) in the genetically improved farmed tilapia (GIFT) strain. In order to quantify the genetic variation in uniformity of traits and estimate the genetic correlations between level and variance of the traits, double hierarchical generalized linear models were applied to individual trait values. Our results showed substantial genetic variation in uniformity of all analyzed traits, with genetic coefficients of variation for residual variance ranging from 39 to 58 %. Genetic correlation between trait level and variance was strongly positive for harvest weight (0.60 ± 0.09), moderate and positive for body depth (0.37 ± 0.13), but not significantly different from 0 for body length and width. Our results on the genetic variation in uniformity of harvest weight and body size traits show good prospects for the genetic improvement of uniformity in the GIFT strain. A high and positive genetic correlation was estimated between level and variance of harvest weight, which suggests that selection for heavier fish will also result in more variation in harvest weight. Simultaneous improvement of harvest weight and its uniformity will thus require index selection.

An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors

Science.gov (United States)

Srbinovski, Bruno; Magno, Michele; Edwards-Murphy, Fiona; Pakrashi, Vikram; Popovici, Emanuel

2016-01-01

Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN) are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA) for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind). Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA) in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources) and power hungry sensors (ultrasonic wind sensor and gas sensors). The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA. PMID:27043559

An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors

Directory of Open Access Journals (Sweden)

Bruno Srbinovski

2016-03-01

Full Text Available Wireless sensor nodes have a limited power budget, though they are often expected to be functional in the field once deployed for extended periods of time. Therefore, minimization of energy consumption and energy harvesting technology in Wireless Sensor Networks (WSN are key tools for maximizing network lifetime, and achieving self-sustainability. This paper proposes an energy aware Adaptive Sampling Algorithm (ASA for WSN with power hungry sensors and harvesting capabilities, an energy management technique that can be implemented on any WSN platform with enough processing power to execute the proposed algorithm. An existing state-of-the-art ASA developed for wireless sensor networks with power hungry sensors is optimized and enhanced to adapt the sampling frequency according to the available energy of the node. The proposed algorithm is evaluated using two in-field testbeds that are supplied by two different energy harvesting sources (solar and wind. Simulation and comparison between the state-of-the-art ASA and the proposed energy aware ASA (EASA in terms of energy durability are carried out using in-field measured harvested energy (using both wind and solar sources and power hungry sensors (ultrasonic wind sensor and gas sensors. The simulation results demonstrate that using ASA in combination with an energy aware function on the nodes can drastically increase the lifetime of a WSN node and enable self-sustainability. In fact, the proposed EASA in conjunction with energy harvesting capability can lead towards perpetual WSN operation and significantly outperform the state-of-the-art ASA.

Detection of suspicious malignant cervical lymph nodes of unknown origin: diagnostic accuracy of ultrasound-guided fine-needle aspiration biopsy with nodal size and central necrosis correlate

International Nuclear Information System (INIS)

Lo, C.-P.; Chen, C.-Y.; Chin, S-.C.; Lee, K.-W.; Hsueh, C.-J.; Juan, C.-J.; Kao, H.-W.; Huang, G.-S.

2007-01-01

To assess the role of ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB) in the diagnostic workup of suspicious malignant cervical lymph nodes in patients with palpable neck masses and without known primary cancer. The diagnostic accuracy of imaging morphologic criteria, including sizes and central necrosis for assessing suspicious malignant nodes, were also examined. This is a retrospective study of 426 patients with palpable neck masses from an outpatient department evaluated with computed tomography, magnetic resonance imaging, or US. US-guided FNABs were performed in 102 patients with suspicious malignant cervical lymph nodes at a single institution. Cytologically positive lymph nodes (n = 12) were further validated with excisional biopsy. Negative lymph nodes (n = 90) were either excised (n = 10) or followed up by imaging studies for at least one year (n = 80). The diagnostic accuracy of the FNABs along with the imaging findings of nodal sizes and presence of central necrosis, which were classified by a consensus of 2 radiologists, were assessed. Twelve malignant nodes were detected with US-guided FNAB with one false-positive and one false-negative result. The overall sensitivity, specificity, and accuracy for FNAB were 91.7%, 98.9%, and 98.0%. respectively. The sensitivity, specificity, and accuracy were 66.7%, 30.0%, and 34.3% for size criterion and 75.0%, 83.3%, and 82.3% for central necrosis criterion. The size of cervical lymph node does not appear to be an important imaging criterion for assessing suspicious malignant lymph nodes, compared with the criterion of central necrosis. US-guided FNAB is highly specific and sensitive in the diagnostic workup of suspicious malignant cervical lymph nodes in patients without known primary cancers. (author)

DEHAR: a Distributed Energy Harvesting Aware Routing Algorithm for Ad-hoc Multi-hop Wireless Sensor Networks

DEFF Research Database (Denmark)

Jakobsen, Mikkel Koefoed; Madsen, Jan; Hansen, Michael Reichhardt

2010-01-01

One of the key design goals in Wireless Sensor Networks is long lasting or even continuous operation. Continuous operation is made possible through energy harvesting. Keeping the network operational imposes a demand to prevent network segmentation and power loss in nodes. It is therefore important...... that the best energy-wise route is found for each data transfer from a source node to the sink node. We present a new adaptive and distributed routing algorithm for finding energy optimised routes in a wireless sensor network with energy harvesting. The algorithm finds an energy efficient route from each source...

A new harvest operation cost model to evaluate forest harvest layout alternatives

Science.gov (United States)

Mark M. Clark; Russell D. Meller; Timothy P. McDonald; Chao Chi Ting

1997-01-01

The authors develop a new model for harvest operation costs that can be used to evaluate stands for potential harvest. The model is based on felling, extraction, and access costs, and is unique in its consideration of the interaction between harvest area shapes and access roads. The scientists illustrate the model and evaluate the impact of stand size, volume, and road...

An electroactive polymer energy harvester for wireless sensor networks

International Nuclear Information System (INIS)

McKay, T G; Rosset, S; Shea, H; Anderson, I A

2013-01-01

This paper reports the design, fabrication, and testing of a soft electroactive polymer power generator that has a volume of 1cm 3 . The generator provides an opportunity to harvest energy from environmental sources to power wireless sensor networks because it can harvest from low frequency motions, is compact, and lightweight. Electroactive polymers are highly stretchable variable capacitors. Electrical energy is produced when the deformation of a stretched, charged electroactive polymer is relaxed; like-charges are compressed together and opposite-charges are pushed apart, resulting in an increased voltage. Although electroactive polymers have impressively displayed energy densities as high as 550 mJ/g, they have been based on films with thicknesses of tens to hundreds of micrometers, thus a generator covering a large area would be required to provide useful power. Energy harvesters covering large areas are inconvenient to deploy in a wireless sensor network with a large number of nodes, so a generator that is compact in all three dimensions is required. In this work we fabricated a generator that can fit within a 11×11×9 mm envelope by stacking 42, 11mm diameter generator films on top of each other. When compressed cyclically at a rate of 0.5 Hz our generator produced 300 uW of power which is a sufficient amount of power for a low power wireless sensor node. The combination of our generator's small form factor and ability to harvest useful energy from low frequency motions provides an opportunity to deploy large numbers of wireless sensor nodes without the need for periodic, costly battery replacement

Energy Harvesting for Aerospace Structural Health Monitoring Systems

International Nuclear Information System (INIS)

Pearson, M R; Eaton, M J; Pullin, R; Featherston, C A; Holford, K M

2012-01-01

Recent research into damage detection methodologies, embedded sensors, wireless data transmission and energy harvesting in aerospace environments has meant that autonomous structural health monitoring (SHM) systems are becoming a real possibility. The most promising system would utilise wireless sensor nodes that are able to make decisions on damage and communicate this wirelessly to a central base station. Although such a system shows great potential and both passive and active monitoring techniques exist for detecting damage in structures, powering such wireless sensors nodes poses a problem. Two such energy sources that could be harvested in abundance on an aircraft are vibration and thermal gradients. Piezoelectric transducers mounted to the surface of a structure can be utilised to generate power from a dynamic strain whilst thermoelectric generators (TEG) can be used to generate power from thermal gradients. This paper reports on the viability of these two energy sources for powering a wireless SHM system from vibrations ranging from 20 to 400Hz and thermal gradients up to 50°C. Investigations showed that using a single vibrational energy harvester raw power levels of up to 1mW could be generated. Further numerical modelling demonstrated that by optimising the position and orientation of the vibrational harvester greater levels of power could be achieved. However using commercial TEGs average power levels over a flight period between 5 to 30mW could be generated. Both of these energy harvesting techniques show a great potential in powering current wireless SHM systems where depending on the complexity the power requirements range from 1 to 180mW.

The Potential for Harvesting Energy from the Movement of Trees

Directory of Open Access Journals (Sweden)

Chris Knight

2011-09-01

Full Text Available Over the last decade, wireless devices have decreased in size and power requirements. These devices generally use batteries as a power source but can employ additional means of power, such as solar, thermal or wind energy. However, sensor networks are often deployed in conditions of minimal lighting and thermal gradient such as densely wooded environments, where even normal wind energy harvesting is limited. In these cases a possible source of energy is from the motion of the trees themselves. We investigated the amount of energy and power available from the motion of a tree in a sheltered position, during Beaufort 4 winds. We measured the work performed by the tree to lift a mass, we measured horizontal acceleration of free movement, and we determined the angular deflection of the movement of the tree trunk, to determine the energy and power available to various types of harvesting devices. We found that the amount of power available from the tree, as demonstrated by lifting a mass, compares favourably with the power required to run a wireless sensor node.

The size and germination of eggplant seed in relation to fruit maturity at harvest, after-ripening and ethylene application

Directory of Open Access Journals (Sweden)

Despoina MAKROGIANNI

2010-11-01

Full Text Available In eggplant cultivars Black Beauty, Emi, Long Negro and Tsakoniki cultivated for seed, flower induction and flower weight decreased in the presence of developing fruit on the plant. Harvesting prior to maturity (25-35 days after anthesis, aimed at increasing flower induction and fruit set, resulted in small seeds that failed to germinate or germinated poorly. When these fruit were stored for 20 days at 25±30C before seed extraction, seed size and germination increased indicating seed filling and maturation (‘after-ripening’ within the harvested fruit. In year 1, a single application of ethylene before storage increased the germination of Black Beauty and Long Negro harvested 25-35 days after anthesis, but reduced that of Emi and Tsakoniki. In year 2, ethylene application once before the storage of fruits harvested 35 days after anthesis promoted the germination of Tsakoniki and Emi, and when ethylene was applied three times germination was increased further. The possible applications of early harvest, fruit storage prior to seed extraction and ethylene treatment to eggplant seed production are discussed.

FR4-based electromagnetic energy harvester for wireless sensor nodes

Science.gov (United States)

Hatipoglu, G.; Ürey, H.

2010-01-01

Electromagnetic (EM) energy harvesting seems to be one of the most promising ways to power wireless sensors in a wireless sensor network. In this paper, FR4, the most commonly used PCB material, is utilized as a mechanical vibrating structure for EM energy harvesting for body-worn sensors and intelligent tire sensors, which involve impact loadings. FR4 can be a better material for such applications compared to silicon MEMS devices due to lower stiffness and broadband response. In order to demonstrate FR4 performance and broadband response, three moving magnet type EM generator designs are developed and investigated throughout the paper. A velocity-damped harvester simulation model is first developed, including a detailed magnetic model and the magnetic damping effects. The numerical results agree well with the experimental results. Human running acceleration at the hip area that is obtained experimentally is simulated in order to demonstrate system performance, which results in a scavenged power of about 40 µW with 15 m s-2 acceleration input. The designed FR4 energy scavengers with mechanical stoppers implemented are particularly well suited for nearly periodic and non-sinusoidal high- g excitations with rich harmonic content. For the intelligent tire applications, a special compact FR4 scavenger is designed that is able to withstand large shocks and vibrations due to mechanical shock stoppers built into the structure. Using our design, 0.4 mW power across a load resistance at off-resonance operation is obtained in shaker experiments. In the actual operation, the tangential accelerations as a result of the tire-road contact are estimated to supply power around 1 mW with our design, which is sufficient for powering wireless tire sensors. The normalized power density (NPD) of the designed actuators compares favorably with most actuators reported in the literature.

FR4-based electromagnetic energy harvester for wireless sensor nodes

International Nuclear Information System (INIS)

Hatipoglu, G; Ürey, H

2010-01-01

Electromagnetic (EM) energy harvesting seems to be one of the most promising ways to power wireless sensors in a wireless sensor network. In this paper, FR4, the most commonly used PCB material, is utilized as a mechanical vibrating structure for EM energy harvesting for body-worn sensors and intelligent tire sensors, which involve impact loadings. FR4 can be a better material for such applications compared to silicon MEMS devices due to lower stiffness and broadband response. In order to demonstrate FR4 performance and broadband response, three moving magnet type EM generator designs are developed and investigated throughout the paper. A velocity-damped harvester simulation model is first developed, including a detailed magnetic model and the magnetic damping effects. The numerical results agree well with the experimental results. Human running acceleration at the hip area that is obtained experimentally is simulated in order to demonstrate system performance, which results in a scavenged power of about 40 µW with 15 m s −2 acceleration input. The designed FR4 energy scavengers with mechanical stoppers implemented are particularly well suited for nearly periodic and non-sinusoidal high- g excitations with rich harmonic content. For the intelligent tire applications, a special compact FR4 scavenger is designed that is able to withstand large shocks and vibrations due to mechanical shock stoppers built into the structure. Using our design, 0.4 mW power across a load resistance at off-resonance operation is obtained in shaker experiments. In the actual operation, the tangential accelerations as a result of the tire–road contact are estimated to supply power around 1 mW with our design, which is sufficient for powering wireless tire sensors. The normalized power density (NPD) of the designed actuators compares favorably with most actuators reported in the literature

Energy-efficient dynamic resource allocation with energy harvesting nodes

OpenAIRE

Rubio López, Javier

2012-01-01

The allocation of radio resources where nodes are battery constrained. [ANGLÈS] In wireless communications, there is a trend to deploy shorter-distance networks to cope with the high demanding necessities of bit-rate that current applications require. In such networks, the power needed for transmission is considerably low, due to proximity between base station and mobile terminals. As a consequence, complex baseband algorithms for signal processing and radio frequency circuitry require an ...

Remaining questions in the case for balanced harvesting

DEFF Research Database (Denmark)

Burgess, Matthew G; Diekert, Florian K; Jacobsen, Nis Sand

2016-01-01

are controversial, including its call for extensive harvesting of juveniles and forage fish. Balanced harvesting also calls for targeting species and size-classes that are not currently marketable, possibly at a significant economic cost. Some have argued that this cost is outweighed by the ecological benefits......Balanced harvesting – harvesting all species and sizes in an ecosystem in proportion to their productivity – is a fisheries management strategy that has been suggested recently to increase yields, while reducing overall ecosystem impact. However, some aspects of balanced harvesting...

Predicting size limit of wild blood python (python brongersmai stull, 1938) harvesting in north sumatera

Science.gov (United States)

Mangantar Pardamean Sianturi, Markus; Jumilawaty, Erni; Delvian; Hartanto, Adrian

2018-03-01

Blood python (Python brongersmai Stull, 1938) is one of heavily exploited wildlife in Indonesia. The high demands on its skin trade have made its harvesting regulated under quota-based setting by the government to prevent over-harvesting. To gain understanding on the sustainability of P. brongersmai in the wild, biological characters of wild-caught specimens were studied. Samples were collected from two slaughterhouses from Rantau Prapat and Langkat. Parameters measured were morphological (Snout-vent length (SVL), body mass, abdomen width) and anatomical characters (Fat classes). Total samples of P. brongersmai in this research were 541 with 269 male and 272 female snakes. Female snakes had the highest proportion of individuals with the best quality of abdominal fat reserves (Class 3). Linear models are built and tested for its significance in relation between fat classes as anatomical characters and morphological characters. All tested morphological characters were significant in female snakes. By using linear equation models, we generate size limit to prioritize harvesting in the future. We suggest the use of SVL and stomach width ranging between 139,7 – 141,5 cm and 24,72 – 25,71 cm respectively to achieve sustainability of P. brongersmai in the wild.

A combimachine for harvesting of small sized trees; Pienpuun keraeilykaatoon perustuvan harvennuskoneen kehittaeminen

Energy Technology Data Exchange (ETDEWEB)

Lilleberg, R [Metsaeteho, Helsinki (Finland)

1997-12-31

The goal of the project was to develop a combimachine suitable for the harvesting of small sized trees in first thinning. The use of such a machine could considerably decrease harvesting costs in first thinning. The basic idea with the combimachine is, that the same machine both fells the trees and transports the timber to roadside storages. A forwarder was equipped with a lightweight felling device, which also can do the crosscutting and loading. When harvesting undelimbed timber the forwarder could be equipped with a load-compressing device. During the spring 1995 a trial was made with a combimachine in a first thinning stand of pine. An ordinary forwarder was equipped with the `Naarva-grapple` a device for felling, crosscutting and loading. The aim was to test how the felling device is working, to examine time expenditure for two different working methods and to collect data for the further development of the machine. The trial showed a need to add a delimbing feature to the Naarva-grapple. The need for delimbing is based on the fact, obtained during the trial, that productivity in transport of delimbed timber was over 30 % higher than in transport of undelimbed pieces. A device capable of delimbing was designed, and it was ready for a prototype test in December 1995. The idea worked, but also showed a lot of details which have to be redesigned, before the device is ready for manufacturing and marketing

A combimachine for harvesting of small sized trees; Pienpuun keraeilykaatoon perustuvan harvennuskoneen kehittaeminen

Energy Technology Data Exchange (ETDEWEB)

Lilleberg, R. [Metsaeteho, Helsinki (Finland)

1996-12-31

The goal of the project was to develop a combimachine suitable for the harvesting of small sized trees in first thinning. The use of such a machine could considerably decrease harvesting costs in first thinning. The basic idea with the combimachine is, that the same machine both fells the trees and transports the timber to roadside storages. A forwarder was equipped with a lightweight felling device, which also can do the crosscutting and loading. When harvesting undelimbed timber the forwarder could be equipped with a load-compressing device. During the spring 1995 a trial was made with a combimachine in a first thinning stand of pine. An ordinary forwarder was equipped with the `Naarva-grapple` a device for felling, crosscutting and loading. The aim was to test how the felling device is working, to examine time expenditure for two different working methods and to collect data for the further development of the machine. The trial showed a need to add a delimbing feature to the Naarva-grapple. The need for delimbing is based on the fact, obtained during the trial, that productivity in transport of delimbed timber was over 30 % higher than in transport of undelimbed pieces. A device capable of delimbing was designed, and it was ready for a prototype test in December 1995. The idea worked, but also showed a lot of details which have to be redesigned, before the device is ready for manufacturing and marketing

Segmentation of a Vibro-Shock Cantilever-Type Piezoelectric Energy Harvester Operating in Higher Transverse Vibration Modes

Directory of Open Access Journals (Sweden)

Darius Zizys

2015-12-01

Full Text Available The piezoelectric transduction mechanism is a common vibration-to-electric energy harvesting approach. Piezoelectric energy harvesters are typically mounted on a vibrating host structure, whereby alternating voltage output is generated by a dynamic strain field. A design target in this case is to match the natural frequency of the harvester to the ambient excitation frequency for the device to operate in resonance mode, thus significantly increasing vibration amplitudes and, as a result, energy output. Other fundamental vibration modes have strain nodes, where the dynamic strain field changes sign in the direction of the cantilever length. The paper reports on a dimensionless numerical transient analysis of a cantilever of a constant cross-section and an optimally-shaped cantilever with the objective to accurately predict the position of a strain node. Total effective strain produced by both cantilevers segmented at the strain node is calculated via transient analysis and compared to the strain output produced by the cantilevers segmented at strain nodes obtained from modal analysis, demonstrating a 7% increase in energy output. Theoretical results were experimentally verified by using open-circuit voltage values measured for the cantilevers segmented at optimal and suboptimal segmentation lines.

Factors associated with involvement of four or more axillary nodes for sentinel lymph node-positive patients

International Nuclear Information System (INIS)

Katz, Angela; Niemierko, Andrzej; Gage, Irene; Evans, Sheila; Shaffer, Margaret; Smith, Frederick P.; Taghian, Alphonse; Magnant, Colette

2006-01-01

Purpose: Sentinel lymph node-positive (SLN+) patients who are unlikely to have 4 or more involved axillary nodes might be treated with less extensive regional nodal radiation. The purpose of this study was to define possible predictors of having 4 or more involved axillary nodes. Methods and Materials: The records of 224 patients with breast cancer and 1 to 3 involved SLNs, who underwent completion axillary dissection without neoadjuvant chemotherapy or hormonal therapy were reviewed. Factors associated with the presence of 4 or more involved axillary nodes (SLNs plus non-SLNs) were evaluated by Pearson chi-square test of association and by simple and multiple logistic-regression analysis. Results: Of 224 patients, 42 had involvement of 4 or more axillary nodes. On univariate analysis, the presence of 4 or more involved axillary nodes was positively associated with increased tumor size, lobular histology, lymphovascular space invasion (LVSI), increased number of involved SLNs, decreased number of uninvolved SLNs, and increased size of SLN metastasis. On multivariate analysis, the presence of 4 or more involved axillary nodes was associated with LVSI, increased number of involved SLNs, increased size of SLN metastasis, and lobular histology. Conclusions: Patients with 1 or more involved SLN, LVSI, or SLN macrometastasis should be treated to the supraclavicular fossa/axillary apex if they do not undergo completion axillary dissection. Other SLN+ patients might be adequately treated with less extensive radiation fields

Detection of metastatic tumor in normal-sized retroperitoneal lymph nodes by monoclonal-antibody imaging

International Nuclear Information System (INIS)

Moldofsky, P.J.; Sears, H.F.; Mulhern, C.B. Jr.; Hammond, N.D.; Powe, J.; Gatenby, R.A.; Steplewski, Z.; Koprowski, H.

1984-01-01

Detection of metastatic colon carcinoma is reported in retroperitoneal lymph nodes that were visible but normal in size (less than 1 cm) and number on CT scanning and at surgery. A case history is presented of 1 of 27 patients with colon carcinoma, metastatic or primary, evaluated with intravenously administered, radiolabeled monoclonal-antibody fragments and subsequent nuclear medicine imaging. Images of /sup 99m/Tc-labeled red cells corresponding to each [ 131 I]antibody view of the abdomen were obtained as a control, to avoid interpretation of simple blood-pool radioactivity as specific localization of antibody on tumor. Antibody images were evaluated both without and with computer blood-pool image substraction. Directed to the level of the left renal hilum by the antibody scan, the surgeon removed the largest palpable node, which measured slightly less than 1 cm in diameter and was not palpably or visibly abnormal to the surgeon until it was removed and sectioned. Pathological evaluation of frozen and permanent sections revealed microscopic foci of adenocarcinoma consistent with a colonic primary tumor. Immunoperoxidase staining for the 1083-17-1A colorectal-carcinoma antigen demonstrated the presence of the antigen in the lymph node. As a result of the detection of this metastasis outside the liver, the patient did not receive the planned hepatic-artery chemotherapy pump but instead received intravenous chemotherapy

Vibration Energy Harvesting Potential for Turbomachinery Applications

Directory of Open Access Journals (Sweden)

Adrian STOICESCU

2018-03-01

Full Text Available The vibration energy harvesting process represents one of the research directions for increasing power efficiency of electric systems, increasing instrumentation nodes autonomy in hard to reach locations and decreasing total system mass by eliminating cables and higher-power adapters. Research based on the possibility of converting vibration energy into useful electric energy is used to evaluate the potential of its use on turbomachinery applications. Aspects such as the structure and characteristics of piezoelectric generators, harvesting networks, their setup and optimization, are considered. Finally, performance test results are shown using piezoelectric systems on a turbine engine.

Localization of Energy Harvesting Empowered Underwater Optical Wireless Sensor Networks

KAUST Repository

Saeed, Nasir

2017-12-20

In this paper, a received signal strength (RSS) based localization technique is developed for energy harvesting underwater optical wireless sensor networks (EH-UOWSNs), where the optical noise sources and channel impairments of seawater pose significant challenges for range estimation. Energy limitation is another major problem due to the limited battery power and difficulty in replacing or recharging the battery of an underwater sensor node. In the proposed framework, sensor nodes with insufficient battery, harvest the energy and starts communicating once it has sufficient energy storage. Network localization is carried out by measuring the RSSs of active nodes, which are modeled based on the underwater optical communication channel characteristics. Thereafter, block kernel matrices are computed for the RSS based range measurements. Unlike the traditional shortest-path approach, the proposed technique reduces the shortest path estimation for each block kernel matrix. Once the complete block kernel matrices are available, a closed form localization technique is developed to find the location of every optical sensor node in the network. Furthermore, an analytical expression for Cramer Rao lower bound (CRLB) is derived as a benchmark to compare the localization performance of the proposed technique. Finally, extensive simulations show that the proposed technique outperforms the well-known network localization techniques.

Self-Powered Wireless Sensor Node Enabled by a Duck-Shaped Triboelectric Nanogenerator for Harvesting Water Wave Energy

KAUST Repository

Ahmed, Abdelsalam

2016-12-08

This paper presents a fully enclosed duck-shaped triboelectric nanogenerator (TENG) for effectively scavenging energy from random and low-frequency water waves. The design of the TENG incorporates the freestanding rolling mode and the pitch motion of a duck-shaped structure generated by incident waves. By investigating the material and structural features, a unit of the TENG device is successfully designed. Furthermore, a hybrid system is constructed using three units of the TENG device. The hybrid system achieves an instantaneous peak current of 65.5 µA with an instantaneous output power density of up to 1.366 W m−2. Following the design, a fluid–solid interaction analysis is carried out on one duck-shaped TENG to understand the dynamic behavior, mechanical efficiency, and stability of the device under various water wave conditions. In addition, the hybrid system is experimentally tested to enable a commercial wireless temperature sensor node. In summary, the unique duck-shaped TENG shows a simple, cost-effective, environmentally friendly, light-weight, and highly stable system. The newly designed TENG is promising for building a network of generators to harvest existing blue energy in oceans, lakes, and rivers.

Self-Powered Wireless Sensor Node Enabled by a Duck-Shaped Triboelectric Nanogenerator for Harvesting Water Wave Energy

KAUST Repository

Ahmed, Abdelsalam; Saadatnia, Zia; Hassan, Islam; Zi, Yunlong; Xi, Yi; He, Xu; Zu, Jean; Wang, Zhong Lin

2016-01-01

This paper presents a fully enclosed duck-shaped triboelectric nanogenerator (TENG) for effectively scavenging energy from random and low-frequency water waves. The design of the TENG incorporates the freestanding rolling mode and the pitch motion of a duck-shaped structure generated by incident waves. By investigating the material and structural features, a unit of the TENG device is successfully designed. Furthermore, a hybrid system is constructed using three units of the TENG device. The hybrid system achieves an instantaneous peak current of 65.5 µA with an instantaneous output power density of up to 1.366 W m−2. Following the design, a fluid–solid interaction analysis is carried out on one duck-shaped TENG to understand the dynamic behavior, mechanical efficiency, and stability of the device under various water wave conditions. In addition, the hybrid system is experimentally tested to enable a commercial wireless temperature sensor node. In summary, the unique duck-shaped TENG shows a simple, cost-effective, environmentally friendly, light-weight, and highly stable system. The newly designed TENG is promising for building a network of generators to harvest existing blue energy in oceans, lakes, and rivers.

Harvest Regulations and Implementation Uncertainty in Small Game Harvest Management

Directory of Open Access Journals (Sweden)

Pål F. Moa

2017-09-01

Full Text Available A main challenge in harvest management is to set policies that maximize the probability that management goals are met. While the management cycle includes multiple sources of uncertainty, only some of these has received considerable attention. Currently, there is a large gap in our knowledge about implemention of harvest regulations, and to which extent indirect control methods such as harvest regulations are actually able to regulate harvest in accordance with intended management objectives. In this perspective article, we first summarize and discuss hunting regulations currently used in management of grouse species (Tetraonidae in Europe and North America. Management models suggested for grouse are most often based on proportional harvest or threshold harvest principles. These models are all built on theoretical principles for sustainable harvesting, and provide in the end an estimate on a total allowable catch. However, implementation uncertainty is rarely examined in empirical or theoretical harvest studies, and few general findings have been reported. Nevertheless, circumstantial evidence suggest that many of the most popular regulations are acting depensatory so that harvest bag sizes is more limited in years (or areas where game density is high, contrary to general recommendations. A better understanding of the implementation uncertainty related to harvest regulations is crucial in order to establish sustainable management systems. We suggest that scenario tools like Management System Evaluation (MSE should be more frequently used to examine robustness of currently applied harvest regulations to such implementation uncertainty until more empirical evidence is available.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

Science.gov (United States)

Balpande, Suresh S.; Pande, Rajesh S.

2016-04-01

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of harvester and

Localization of Energy Harvesting Empowered Underwater Optical Wireless Sensor Networks

KAUST Repository

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

with insufficient battery, harvest the energy and starts communicating once it has sufficient energy storage. Network localization is carried out by measuring the RSSs of active nodes, which are modeled based on the underwater optical communication channel

Energy harvesting from organic liquids in micro-sized microbial fuel cells

KAUST Repository

Mink, J.E.

2014-03-07

Micro-sized microbial fuel cells (MFCs) are miniature energy harvesters that use bacteria to convert biomass from liquids into usable power. The key challenge is transitioning laboratory test beds into devices capable of producing high power using readily available fuel sources. Here, we present a pragmatic step toward advancing MFC applications through the fabrication of a uniquely mobile and inexpensive micro-sized device that can be fueled with human saliva. The 25-ll MFC was fabricated with graphene, a two-dimensional atomic crystal-structured material, as an anode for efficient current generation and with an air cathode for enabling the use of the oxygen present in air, making its operation completely mobile and free of the need for laboratory chemicals. With saliva as a fuel, the device produced higher current densities (1190 Am-3) than any previous aircathode micro-sized MFCs. The use of the graphene anode generated 40 times more power than that possible using a carbon cloth anode. Additional tests were performed using acetate, a conventional organic material, at high organic loadings that were comparable to those in saliva, and the results demonstrated a linear relationship between the organic loading and current. These findings open the door to saliva-powered applications of this fuel cell technology for Lab-on-a-Chip devices or portable point-of-care diagnostic devices. 2014 Nature Publishing Group All rights reserved 1884-4057/14.

Powering a wireless sensor node with a vibration-driven piezoelectric energy harvester

International Nuclear Information System (INIS)

Reilly, Elizabeth K; Wright, Paul; Burghardt, Fred; Fain, Romy

2011-01-01

This paper discusses the direct application of scavenged energy to power a wireless sensor platform. A trapezoidal piezoelectric harvester was designed for a specific machine tool application and tested for robustness and longevity as well as performance. The design focused on resonant performance and distributed strain concentrations at a given resonant frequency and acceleration. Critical issues of power coupling and conditioning between harvester and wireless platform were addressed. The wireless platform consisted of a sensor, controller, power conditioning circuitry, and a custom low power radio. The system transmitted a sensor sample once every 10 s in a scavenging environment of 0.25 g and 100 Hz for a system duty cycle of approximately 0.2%

Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion

Science.gov (United States)

Khan, Farid Ullah; Izhar

2016-02-01

This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester.

Size variability of the unit building block of peripheral light-harvesting antennas as a strategy for effective functioning of antennas of variable size that is controlled in vivo by light intensity.

Science.gov (United States)

Taisova, A S; Yakovlev, A G; Fetisova, Z G

2014-03-01

This work continuous a series of studies devoted to discovering principles of organization of natural antennas in photosynthetic microorganisms that generate in vivo large and highly effective light-harvesting structures. The largest antenna is observed in green photosynthesizing bacteria, which are able to grow over a wide range of light intensities and adapt to low intensities by increasing of size of peripheral BChl c/d/e antenna. However, increasing antenna size must inevitably cause structural changes needed to maintain high efficiency of its functioning. Our model calculations have demonstrated that aggregation of the light-harvesting antenna pigments represents one of the universal structural factors that optimize functioning of any antenna and manage antenna efficiency. If the degree of aggregation of antenna pigments is a variable parameter, then efficiency of the antenna increases with increasing size of a single aggregate of the antenna. This means that change in degree of pigment aggregation controlled by light-harvesting antenna size is biologically expedient. We showed in our previous work on the oligomeric chlorosomal BChl c superantenna of green bacteria of the Chloroflexaceae family that this principle of optimization of variable antenna structure, whose size is controlled by light intensity during growth of bacteria, is actually realized in vivo. Studies of this phenomenon are continued in the present work, expanding the number of studied biological materials and investigating optical linear and nonlinear spectra of chlorosomes having different structures. We show for oligomeric chlorosomal superantennas of green bacteria (from two different families, Chloroflexaceae and Oscillochloridaceae) that a single BChl c aggregate is of small size, and the degree of BChl c aggregation is a variable parameter, which is controlled by the size of the entire BChl c superantenna, and the latter, in turn, is controlled by light intensity in the course of cell

Packaging strategy for maximizing the performance of a screen printed piezoelectric energy harvester

International Nuclear Information System (INIS)

Zhang, Z; Zhu, D; Tudor, M J; Beeby, S P

2013-01-01

This paper reports the extended design and simulation of a screen printed piezoelectric energy harvester. The proposed design was based on a previous credit card sized smart tag sensor node, and packages the power conditioning circuit in the free space above the tungsten proof mass layer. This approach enables electronic components to be mounted onto the cantilever beam, which provides additional weight at the tip of the cantilever structure. The design structure contains a T-shape cantilever beam with size of 47 mm × 30 mm × 0.85 mm which is fabricated using screen printing. ANSYS simulation results predict the revised architecture can generate 421.9 μW approximately twice of the RMS power produced by the original design along with a higher open-circuit RMS Voltage of 8.0 V while the resonant frequency is dropped to 53.4 Hz

A Design Study Of A Wireless Power Transfer System For Use To Transfer Energy From A Vibration Energy Harvester

Science.gov (United States)

Grabham, N. J.; Harden, C.; Vincent, D.; Beeby, S. P.

2016-11-01

A wirelessly powered remote sensor node is presented along with its design process. The purpose of the node is the further expansion of the sensing capabilities of the commercial Perpetuum system used for condition monitoring on trains and rolling stock which operates using vibration energy harvesting. Surplus harvested vibration energy is transferred wirelessly to a remote satellite sensor to allow measurements over a wider area to be made. This additional data is to be used for long term condition monitoring. Performance measurements made on the prototype remote sensor node are reported and advantages and disadvantages of using the same RF frequency for power and data transfer are identified.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

Directory of Open Access Journals (Sweden)

Nasir Saeed

2017-12-01

Full Text Available Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization.

Science.gov (United States)

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y; Alouini, Mohamed-Slim

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

KAUST Repository

Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Energy Harvesting Hybrid Acoustic-Optical Underwater Wireless Sensor Networks Localization

KAUST Repository

Saeed, Nasir

2017-12-26

Underwater wireless technologies demand to transmit at higher data rate for ocean exploration. Currently, large coverage is achieved by acoustic sensor networks with low data rate, high cost, high latency, high power consumption, and negative impact on marine mammals. Meanwhile, optical communication for underwater networks has the advantage of the higher data rate albeit for limited communication distances. Moreover, energy consumption is another major problem for underwater sensor networks, due to limited battery power and difficulty in replacing or recharging the battery of a sensor node. The ultimate solution to this problem is to add energy harvesting capability to the acoustic-optical sensor nodes. Localization of underwater sensor networks is of utmost importance because the data collected from underwater sensor nodes is useful only if the location of the nodes is known. Therefore, a novel localization technique for energy harvesting hybrid acoustic-optical underwater wireless sensor networks (AO-UWSNs) is proposed. AO-UWSN employs optical communication for higher data rate at a short transmission distance and employs acoustic communication for low data rate and long transmission distance. A hybrid received signal strength (RSS) based localization technique is proposed to localize the nodes in AO-UWSNs. The proposed technique combines the noisy RSS based measurements from acoustic communication and optical communication and estimates the final locations of acoustic-optical sensor nodes. A weighted multiple observations paradigm is proposed for hybrid estimated distances to suppress the noisy observations and give more importance to the accurate observations. Furthermore, the closed form solution for Cramer-Rao lower bound (CRLB) is derived for localization accuracy of the proposed technique.

Refreshing Music: Fog Harvesting with Harps

Science.gov (United States)

Shi, Weiwei; Anderson, Mark; Kennedy, Brook; Boreyko, Jonathan

2017-11-01

Fog harvesting is a useful technique for obtaining fresh water in arid climates. The wire meshes currently utilized for fog harvesting suffer from dual constraints: coarse meshes cannot efficiently capture fog, while fine meshes suffer from clogging issues. Here, we design a new type of fog harvester comprised of an array of vertical wires, which we call ``fog harps.'' To investigate the water collection efficiency, three fog harps were designed with different diameters (254 μm, 508 μm and 1.30 mm) but the same pitch-to-diameter ratio of 2. For comparison, three different size meshes were purchased with equivalent dimensions. As expected for the mesh structures, the mid-sized wires performed the best, with a drop-off in performance for the fine or coarse meshes. In contrast, the fog harvesting rate continually increased with decreasing wire diameter for the fog harps, due to its low hysteresis that prevented droplet clogging. This resulted in a 3-fold enhancement in the fog harvesting rate for the harp form factor compared to the mesh. The lack of a performance ceiling for the harps suggest that even greater enhancements could be achieved by scaling down to yet smaller sizes.

Recent Progress on PZT Based Piezoelectric Energy Harvesting Technologies

Directory of Open Access Journals (Sweden)

Min-Gyu Kang

2016-02-01

Full Text Available Energy harvesting is the most effective way to respond to the energy shortage and to produce sustainable power sources from the surrounding environment. The energy harvesting technology enables scavenging electrical energy from wasted energy sources, which always exist everywhere, such as in heat, fluids, vibrations, etc. In particular, piezoelectric energy harvesting, which uses a direct energy conversion from vibrations and mechanical deformation to the electrical energy, is a promising technique to supply power sources in unattended electronic devices, wireless sensor nodes, micro-electronic devices, etc., since it has higher energy conversion efficiency and a simple structure. Up to now, various technologies, such as advanced materials, micro- and macro-mechanics, and electric circuit design, have been investigated and emerged to improve performance and conversion efficiency of the piezoelectric energy harvesters. In this paper, we focus on recent progress of piezoelectric energy harvesting technologies based on PbZrxTi1-xO3 (PZT materials, which have the most outstanding piezoelectric properties. The advanced piezoelectric energy harvesting technologies included materials, fabrications, unique designs, and properties are introduced to understand current technical levels and suggest the future directions of piezoelectric energy harvesting.

EHRA: Specification and Analysis of Energy-Harvesting Wireless Sensor Networks

DEFF Research Database (Denmark)

Dung, Phan Anh; Hansen, Michael Reichhardt; Madsen, Jan

2014-01-01

Although energy consumption of wireless sensor network has been studied extensively, we are far behind in understanding the dynamics of the power consumption along with energy production using harvesters. We introduce Energy Harvesting Routing Analysis (EHRA) as a formal modelling framework...... to study wireless sensor networks (WSN) with energy-harvesting capabilities. The purpose of the framework is to analyze WSNs at a high level of abstraction, that is, before the protocols are implemented and before the WSN is deployed. The conceptual basis of EHRA comprises the environment, the medium...... is developed as a simulator implemented using the functional programming language F#. This simulator is used to analyze global properties of WSNs such as network fragmentation,routing trends, and energy profiles for the nodes. Three routing protocols, with a progression in the energy-harvesting awareness...

How size evaluation of lymph node is protocol dependent in MRI when using ultrasmall superparamagnetic iron oxide nanoparticles

International Nuclear Information System (INIS)

Gharehaghaji, Nahideh; Oghabian, Mohammad Ali; Sarkar, Saeed; Darki, Fahimeh; Beitollahi, Ali

2009-01-01

In this study, the volume of susceptibility artifact was evaluated in T1 and T2-weighted spin echo (SE) and gradient echo (GRE) images at various parameters using registration and subtraction methods. In order to state an important misinterpretation problem in lymphography, it was demonstrated that a lymph node size may be enlarged approximately 10 times when a T2*-weighted GRE protocol is used. To overcome this problem a technical consideration using multisequence (GRE and SE) paradigm was suggested to ensure both lymph node detection and metastasis identification in lymphatic system. The paradigm was also extended by post-processing manipulation of the SE images using a registration and subtraction approach for detection of lymphatic lesions.

Optimal task scheduling policy in energy harvesting wireless sensor networks

NARCIS (Netherlands)

Rao, Vijay S.; Prasad, R. Venkatesha; Niemegeers, Ignas G M M

2015-01-01

Ambient energy harvesting for Wireless Sensor Networks (WSNs) is being pitched as a promising solution for long-lasting deployments in various WSN applications. However, the sensor nodes most often do not have enough energy to handle application, network and house-keeping tasks because amount of

Effect of harvest time and physical form of alfalfa silage on chewing time and particle size distribution in boli, rumen content and faeces

DEFF Research Database (Denmark)

Kornfelt, L. F.; Weisbjerg, Martin Riis; Norgaard, P.

2013-01-01

The study examined the effects of physical form and harvest time of alfalfa silage on eating and ruminating activity and particle size distribution in feed boli, rumen content and faeces in dry cows. The alfalfa crop was harvested at two stages of growth (early: NDF 37 late: NDF 44% in dry matter.......01), physical form (P time (P distribution function...... fractions. The length (PL) and width (PW) of particles within each fraction was measured by the use of image analysis. The eating activity (min/kg dry matter intake (P time. The mean ruminating time (min/kg DM) was affected by harvest time (P

Predicting Likelihood of Having Four or More Positive Nodes in Patient With Sentinel Lymph Node-Positive Breast Cancer: A Nomogram Validation Study

International Nuclear Information System (INIS)

Unal, Bulent; Gur, Akif Serhat; Beriwal, Sushil; Tang Gong; Johnson, Ronald; Ahrendt, Gretchen; Bonaventura, Marguerite; Soran, Atilla

2009-01-01

Purpose: Katz suggested a nomogram for predicting having four or more positive nodes in sentinel lymph node (SLN)-positive breast cancer patients. The findings from this formula might influence adjuvant radiotherapy decisions. Our goal was to validate the accuracy of the Katz nomogram. Methods and Materials: We reviewed the records of 309 patients with breast cancer who had undergone completion axillary lymph node dissection. The factors associated with the likelihood of having four or more positive axillary nodes were evaluated in patients with one to three positive SLNs. The nomogram developed by Katz was applied to our data set. The area under the curve of the corresponding receiver operating characteristics curve was calculated for the nomogram. Results: Of the 309 patients, 80 (25.9%) had four or more positive axillary lymph nodes. On multivariate analysis, the number of positive SLNs (p < .0001), overall metastasis size (p = .019), primary tumor size (p = .0001), and extracapsular extension (p = .01) were significant factors predicting for four or more positive nodes. For patients with <5% probability, 90.3% had fewer than four positive nodes and 9.7% had four or more positive nodes. The negative predictive value was 91.7%, and sensitivity was 80%. The nomogram was accurate and discriminating (area under the curve, .801). Conclusion: The probability of four or more involved nodes is significantly greater in patients who have an increased number of positive SLNs, increased overall metastasis size, increased tumor size, and extracapsular extension. The Katz nomogram was validated in our patients. This nomogram will be helpful to clinicians making adjuvant treatment recommendations to their patients.

Fog Harvesting with Harps.

Science.gov (United States)

Shi, Weiwei; Anderson, Mark J; Tulkoff, Joshua B; Kennedy, Brook S; Boreyko, Jonathan B

2018-04-11

Fog harvesting is a useful technique for obtaining fresh water in arid climates. The wire meshes currently utilized for fog harvesting suffer from dual constraints: coarse meshes cannot efficiently capture microscopic fog droplets, whereas fine meshes suffer from clogging issues. Here, we design and fabricate fog harvesters comprising an array of vertical wires, which we call "fog harps". Under controlled laboratory conditions, the fog-harvesting rates for fog harps with three different wire diameters were compared to conventional meshes of equivalent dimensions. As expected for the mesh structures, the mid-sized wires exhibited the largest fog collection rate, with a drop-off in performance for the fine or coarse meshes. In contrast, the fog-harvesting rate continually increased with decreasing wire diameter for the fog harps due to efficient droplet shedding that prevented clogging. This resulted in a 3-fold enhancement in the fog-harvesting rate for the harp design compared to an equivalent mesh.

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

Energy Technology Data Exchange (ETDEWEB)

Balpande, Suresh S., E-mail: balpandes@rknec.edu [Ph.D.. Scholar, Department of Electronics Engineering Shri Ramdeobaba College of Engineering & Management, Nagpur-13, (M.S.) (India); Pande, Rajesh S. [Professor, Department of Electronics Engineering Shri Ramdeobaba College of Engineering & Management, Nagpur-13, (M.S.) (India)

2016-04-13

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of

Design and fabrication of non silicon substrate based MEMS energy harvester for arbitrary surface applications

International Nuclear Information System (INIS)

Balpande, Suresh S.; Pande, Rajesh S.

2016-01-01

Internet of Things (IoT) uses MEMS sensor nodes and actuators to sense and control objects through Internet. IOT deploys millions of chemical battery driven sensors at different locations which are not reliable many times because of frequent requirement of charging & battery replacement in case of underground laying, placement at harsh environmental conditions, huge count and difference between demand (24 % per year) and availability (energy density growing rate 8% per year). Energy harvester fabricated on silicon wafers have been widely used in manufacturing MEMS structures. These devices require complex fabrication processes, costly chemicals & clean room. In addition to this silicon wafer based devices are not suitable for curved surfaces like pipes, human bodies, organisms, or other arbitrary surface like clothes, structure surfaces which does not have flat and smooth surface always. Therefore, devices based on rigid silicon wafers are not suitable for these applications. Flexible structures are the key solution for this problems. Energy transduction mechanism generates power from free surrounding vibrations or impact. Sensor nodes application has been purposefully selected due to discrete power requirement at low duty cycle. Such nodes require an average power budget in the range of about 0.1 microwatt to 1 mW over a period of 3-5 seconds. Energy harvester is the best alternate source in contrast with battery for sensor node application. Novel design of Energy Harvester based on cheapest flexible non silicon substrate i.e. cellulose acetate substrate have been modeled, simulated and analyzed on COMSOL multiphysics and fabricated using sol-gel spin coating setup. Single cantilever based harvester generates 60-75 mV peak electric potential at 22Hz frequency and approximately 22 µW power at 1K-Ohm load. Cantilever array can be employed for generating higher voltage by replicating this structure. This work covers design, optimization, fabrication of

Energy harvesting: small scale energy production from ambient sources

Science.gov (United States)

Yeatman, Eric M.

2009-03-01

Energy harvesting - the collection of otherwise unexploited energy in the local environment - is attracting increasing attention for the powering of electronic devices. While the power levels that can be reached are typically modest (microwatts to milliwatts), the key motivation is to avoid the need for battery replacement or recharging in portable or inaccessible devices. Wireless sensor networks are a particularly important application: the availability of essentially maintenance free sensor nodes, as enabled by energy harvesting, will greatly increase the feasibility of large scale networks, in the paradigm often known as pervasive sensing. Such pervasive sensing networks, used to monitor buildings, structures, outdoor environments or the human body, offer significant benefits for large scale energy efficiency, health and safety, and many other areas. Sources of energy for harvesting include light, temperature differences, and ambient motion, and a wide range of miniature energy harvesters based on these sources have been proposed or demonstrated. This paper reviews the principles and practice in miniature energy harvesters, and discusses trends, suitable applications, and possible future developments.

Sentinel Lymph Node Biopsy in Breast Cancer: Predictors of Axillary and Non-Sentinel Lymph Node Involvement

Directory of Open Access Journals (Sweden)

Hakan Postacı

2013-12-01

Full Text Available Background: Sentinel lymph node biopsy is a standard method for the evaluation of axillary status in patients with T1-2N0M0 breast cancers. Aims: To determine the prognostic significance of primary tumour-related clinico-histopathological factors on axillary and non-sentinel lymph node involvement of patients who underwent sentinel lymph node biopsy. Study design: Retrospective clinical study. Methods: In the present study, 157 sentinel lymph node biopsies were performed in 151 consecutive patients with early stage breast cancer between June 2008 and December 2011. Results: Successful lymphatic mapping was obtained in 157 of 158 procedures (99.4%. The incidence of larger tumour size (2.543±1.21 vs. 1.974±1.04, lymphatic vessel invasion (70.6% vs. 29.4%, blood vessel invasion (84.2% vs. 15.8%, and invasive lobular carcinoma subtype (72.7% vs. 27.3% were statistically significantly higher in patients with positive SLNs. Logistic stepwise regression analysis disclosed tumour size (odds ratio: 1.51, p=0.0021 and lymphatic vessel invasion (odds ratio: 4.68, p=0.001 as significant primary tumour-related prognostic determinants of SLN metastasis. Conclusion: A close relationship was identified between tumour size and lymphatic vessel invasion of the primary tumour and axillary lymph node involvement. However, the positive predictive value of these two independent variables is low and there is no compelling evidence to recommend their use in routine clinical practice.

Adaptive Media Access Control for Energy Harvesting - Wireless Sensor Networks

DEFF Research Database (Denmark)

Fafoutis, Xenofon; Dragoni, Nicola

2012-01-01

ODMAC (On-Demand Media Access Control) is a recently proposed MAC protocol designed to support individual duty cycles for Energy Harvesting — Wireless Sensor Networks (EH-WSNs). Individual duty cycles are vital for EH-WSNs, because they allow nodes to adapt their energy consumption to the ever-ch...

Stability-Aware Geographic Routing in Energy Harvesting Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Tran Dinh Hieu

2016-05-01

Full Text Available A new generation of wireless sensor networks that harvest energy from environmental sources such as solar, vibration, and thermoelectric to power sensor nodes is emerging to solve the problem of energy limitation. Based on the photo-voltaic model, this research proposes a stability-aware geographic routing for reliable data transmissions in energy-harvesting wireless sensor networks (EH-WSNs to provide a reliable routes selection method and potentially achieve an unlimited network lifetime. Specifically, the influences of link quality, represented by the estimated packet reception rate, on network performance is investigated. Simulation results show that the proposed method outperforms an energy-harvesting-aware method in terms of energy consumption, the average number of hops, and the packet delivery ratio.

Review of magnetostrictive vibration energy harvesters

Science.gov (United States)

Deng, Zhangxian; Dapino, Marcelo J.

2017-10-01

The field of energy harvesting has grown concurrently with the rapid development of portable and wireless electronics in which reliable and long-lasting power sources are required. Electrochemical batteries have a limited lifespan and require periodic recharging. In contrast, vibration energy harvesters can supply uninterrupted power by scavenging useful electrical energy from ambient structural vibrations. This article reviews the current state of vibration energy harvesters based on magnetostrictive materials, especially Terfenol-D and Galfenol. Existing magnetostrictive harvester designs are compared in terms of various performance metrics. Advanced techniques that can reduce device size and improve performance are presented. Models for magnetostrictive devices are summarized to guide future harvester designs.

Piezoelectric energy harvester under parquet floor

Science.gov (United States)

Bischur, E.; Schwesinger, N.

2011-03-01

The design, fabrication and testing of piezoelectric energy harvesting modules for floors is described. These modules are used beneath a parquet floor to harvest the energy of people walking over it. The harvesting modules consist of monoaxial stretched PVDF-foils. Multilayer modules are built up as roller-type capacitors. The fabrication process of the harvesting modules is simple and very suitable for mass production. Due to the use of organic polymers, the modules are characterized by a great flexibility and the possibility to create them in almost any geometrical size. The energy yield was determined depending on the dynamic loading force, the thickness of piezoelectric active material, the size of the piezoelectric modules, their alignment in the walking direction and their position on the floor. An increase of the energy yield at higher loading forces and higher thicknesses of the modules was observed. It was possible to generate up to 2.1mWs of electric energy with dynamic loads of 70kg using a specific module design. Furthermore a test floor was assembled to determine the influence of the size, alignment and position of the modules on the energy yield.

Increasing the Lifetime of Mobile WSNs via Dynamic Optimization of Sensor Node Communication Activity

Directory of Open Access Journals (Sweden)

Dayan Adionel Guimarães

2016-09-01

Full Text Available In this paper, a simple and flexible method for increasing the lifetime of fixed or mobile wireless sensor networks is proposed. Based on past residual energy information reported by the sensor nodes, the sink node or another central node dynamically optimizes the communication activity levels of the sensor nodes to save energy without sacrificing the data throughput. The activity levels are defined to represent portions of time or time-frequency slots in a frame, during which the sensor nodes are scheduled to communicate with the sink node to report sensory measurements. Besides node mobility, it is considered that sensors’ batteries may be recharged via a wireless power transmission or equivalent energy harvesting scheme, bringing to the optimization problem an even more dynamic character. We report large increased lifetimes over the non-optimized network and comparable or even larger lifetime improvements with respect to an idealized greedy algorithm that uses both the real-time channel state and the residual energy information.

Increasing the Lifetime of Mobile WSNs via Dynamic Optimization of Sensor Node Communication Activity.

Science.gov (United States)

Guimarães, Dayan Adionel; Sakai, Lucas Jun; Alberti, Antonio Marcos; de Souza, Rausley Adriano Amaral

2016-09-20

In this paper, a simple and flexible method for increasing the lifetime of fixed or mobile wireless sensor networks is proposed. Based on past residual energy information reported by the sensor nodes, the sink node or another central node dynamically optimizes the communication activity levels of the sensor nodes to save energy without sacrificing the data throughput. The activity levels are defined to represent portions of time or time-frequency slots in a frame, during which the sensor nodes are scheduled to communicate with the sink node to report sensory measurements. Besides node mobility, it is considered that sensors' batteries may be recharged via a wireless power transmission or equivalent energy harvesting scheme, bringing to the optimization problem an even more dynamic character. We report large increased lifetimes over the non-optimized network and comparable or even larger lifetime improvements with respect to an idealized greedy algorithm that uses both the real-time channel state and the residual energy information.

[The effect of mammographic screening on tumor size, axillary node status and the degree of histologic anaplasia].

Science.gov (United States)

Garami, Zoltán; Benkó, Klára; Kósa, Csaba; Fülöp, Balázs; Lukács, Géza

2006-10-01

Breast cancer is the most frequent malignant tumor in women in Hungary. Significant reduction of mortality has been brought about not only by the increasing efficiency of complex therapy but also by regular mammographic screening. Of the histopathological data of 633 patients operated with primary breast tumor at the 1st Surgical Clinic of the Debrecen Medical University between January 1st 2000 and December 31st 2004, the authors analyzed tumor diameter, axillary node status and the degree of histologic anaplasia and compared them with the data of mammographic screening. Of the "screened"patients, 70.7% were diagnosed with T1 size tumors, 28.5% with T2 size, and 0.8% with tumors bigger than that. In the "unscreened" patients, our findings were 44.3%, 45.9% and 9.8% respectively. Within T1 tumors, Tla tumors were found in 11%, TIb in 37.6% and T1c in 51.4% in the "screened" group of patients, while the "unscreened" group's results were 2.3%, 12.6% and 85% respectively. 72.7% of the "screened" patients and 56.2% of the "unscreened" patients were found to be axillary node-negative. A study of the degree of histologic anaplasia showed G-I tumors in 15.6%, G-IIs in 62.1% and G-IIIs in 22.3% of the "screened" patients. The corresponding values for the "unscreened" patients were 6.1%, 53.8% and 40.1%, respectively. The differences were highly significant (p < 0.001) in all the parameters investigated. The authors have found a significant increase in the proportion of node-negative patients and patients with smaller tumors even after the first round of mammographic screening and at less than 50% participation. It is to be hoped that a 20% reduction in mortality can be achieved by further increasing the rate of participation.

Wireless energy transmission to supplement energy harvesters in sensor network applications

Energy Technology Data Exchange (ETDEWEB)

Farinholt, Kevin M [Los Alamos National Laboratory; Taylor, Stuart G [Los Alamos National Laboratory; Park, Gyuhae [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory

2010-01-01

In this paper we present a method for coupling wireless energy transmission with traditional energy harvesting techniques in order to power sensor nodes for structural health monitoring applications. The goal of this study is to develop a system that can be permanently embedded within civil structures without the need for on-board power sources. Wireless energy transmission is included to supplement energy harvesting techniques that rely on ambient or environmental, energy sources. This approach combines several transducer types that harvest ambient energy with wireless transmission sources, providing a robust solution that does not rely on a single energy source. Experimental results from laboratory and field experiments are presented to address duty cycle limitations of conventional energy harvesting techniques, and the advantages gained by incorporating a wireless energy transmission subsystem. Methods of increasing the efficiency, energy storage medium, target applications and the integrated use of energy harvesting sources with wireless energy transmission will be discussed.

Is the identification of in-transit sentinel lymph nodes in malignant melanoma patients really necessary?

International Nuclear Information System (INIS)

Vidal-Sicart, Sergi; Pons, Francesca; Fuertes, Silvia; Ortega, Marisa; Vilalta, Antonio; Puig, Susana; Palou, Josep M.; Castel, Teresa; Rull, Ramon

2004-01-01

The sentinel lymph node (SLN) is the first node in a nodal basin to receive the direct lymphatic flow from a malignant melanoma. However, in some patients, lymphoscintigraphic study reveals the presence of lymphatic nodes in the area between the primary melanoma and the regional basin. These nodes are called ''in-transit nodes'' or ''interval nodes'' and, by definition, are also SLNs. The purpose of this study was to determine the incidence and location of in-transit SLNs in patients with malignant melanoma and to assess whether it is really necessary to harvest them. The evaluation involved 600 consecutive malignant melanoma patients. Lymphoscintigraphy was performed on the day before surgery following intradermal injection of 74-111 MBq of 99m Tc-nanocolloid in four doses around the primary melanoma or the biopsy scar. Dynamic and static images were obtained and revealed SLNs in 599 out of 600 patients. The SLN was intraoperatively identified with the aid of patent blue dye and a hand-held gamma probe. Lymphoscintigraphy showed in-transit SLNs in 59/599 patients (9.8%). During surgery, all these in-transit SLNs were harvested, with those in the popliteal and epitrochlear regions being the most difficult to identify and excise. Metastatic cell deposits were subsequently identified in ten (16.9%) of these in-transit SLNs. In conclusion, lymphoscintigraphy has a key role in the identification of in-transit SLNs. Although the incidence of these nodes is relatively low in malignant melanoma patients, such SLNs present metastatic deposits in a significant percentage of cases and therefore the identification of in-transit SLNs in these patients is really necessary. (orig.)

CMOS indoor light energy harvesting system for wireless sensing applications

CERN Document Server

Ferreira Carvalho, Carlos Manuel

2016-01-01

This book discusses in detail the CMOS implementation of energy harvesting.  The authors describe an integrated, indoor light energy harvesting system, based on a controller circuit that dynamically and automatically adjusts its operation to meet the actual light circumstances of the environment where the system is placed.  The system is intended to power a sensor node, enabling an autonomous wireless sensor network (WSN). Although designed to cope with indoor light levels, the system is also able to work with higher levels, making it an all-round light energy harvesting system.  The discussion includes experimental data obtained from an integrated manufactured prototype, which in conjunction with a photovoltaic (PV) cell, serves as a proof of concept of the desired energy harvesting system.  ·         Discusses several energy sources which can be used to power energy harvesting systems and includes an overview of PV cell technologies  ·         Includes an introduction to voltage step-...

Human-motion energy harvester for autonomous body area sensors

Science.gov (United States)

Geisler, M.; Boisseau, S.; Perez, M.; Gasnier, P.; Willemin, J.; Ait-Ali, I.; Perraud, S.

2017-03-01

This paper reports on a method to optimize an electromagnetic energy harvester converting the low-frequency body motion and aimed at powering wireless body area sensors. This method is based on recorded accelerations, and mechanical and transduction models that enable an efficient joint optimization of the structural parameters. An optimized prototype of 14.8 mmØ × 52 mm, weighting 20 g, has generated up to 4.95 mW in a resistive load when worn at the arm during a run, and 6.57 mW when hand-shaken. Among the inertial electromagnetic energy harvesters reported so far, this one exhibits one of the highest power densities (up to 730 μW cm-3). The energy harvester was finally used to power a bluetooth low energy wireless sensor node with accelerations measurements at 25 Hz.

Effect of harvest time and physical form of alfalfa silage on chewing time and particle size distribution in boli, rumen content and faeces.

Science.gov (United States)

Kornfelt, L F; Weisbjerg, M R; Nørgaard, P

2013-02-01

The study examined the effects of physical form and harvest time of alfalfa silage on eating and ruminating activity and particle size distribution in feed boli, rumen content and faeces in dry cows. The alfalfa crop was harvested at two stages of growth (early: NDF 37%, late: NDF 44% in dry matter (DM)), and from each harvest, a chopped (theoretical cutting length: 19 mm) and an unchopped crop was ensiled in bales. The silages were fed restrictively to four rumen cannulated non-lactating Jersey cows (391 ± 26 kg) in a 4 × 4 Latin square design. The cows were fed restrictively 80% of their ad libitum intake twice daily. Chewing activity was recorded for 96 h continuously. Swallowed boli, rumen content, rumen fluid and faeces samples were collected, washed in nylon bags (0.01 mm pore size) and freeze-dried before dry sieving through 4.750, 2.360, 1.000, 0.500 and 0.212 mm pore sizes into six fractions. The length (PL) and width (PW) of particles within each fraction was measured by the use of image analysis. The eating activity (min/kg dry matter intake (P rumen content, rumen fluid and faeces was affected by harvest time (P rumen content and faeces were identified. Chopping of the silage decreased the mean PL and PW, the most frequent PL (mode) and 95% percentile PL and PW values in boli. In the rumen content, chopping increased the mean PW (P rumen content and faeces than in boli (P rumen contents (P rumen content and faeces particles are most likely related to the leaf and the stem residues.

Joint sensor placement and power rating selection in energy harvesting wireless sensor networks

KAUST Repository

Bushnaq, Osama M.; Al-Naffouri, Tareq Y.; Chepuri, Sundeep Prabhakar; Leus, Geert

2017-01-01

In this paper, the focus is on optimal sensor placement and power rating selection for parameter estimation in wireless sensor networks (WSNs). We take into account the amount of energy harvested by the sensing nodes, communication link quality

Nanoscale piezoelectric vibration energy harvester design

Science.gov (United States)

Foruzande, Hamid Reza; Hajnayeb, Ali; Yaghootian, Amin

2017-09-01

Development of new nanoscale devices has increased the demand for new types of small-scale energy resources such as ambient vibrations energy harvesters. Among the vibration energy harvesters, piezoelectric energy harvesters (PEHs) can be easily miniaturized and fabricated in micro and nano scales. This change in the dimensions of a PEH leads to a change in its governing equations of motion, and consequently, the predicted harvested energy comparing to a macroscale PEH. In this research, effects of small scale dimensions on the nonlinear vibration and harvested voltage of a nanoscale PEH is studied. The PEH is modeled as a cantilever piezoelectric bimorph nanobeam with a tip mass, using the Euler-Bernoulli beam theory in conjunction with Hamilton's principle. A harmonic base excitation is applied as a model of the ambient vibrations. The nonlocal elasticity theory is used to consider the size effects in the developed model. The derived equations of motion are discretized using the assumed-modes method and solved using the method of multiple scales. Sensitivity analysis for the effect of different parameters of the system in addition to size effects is conducted. The results show the significance of nonlocal elasticity theory in the prediction of system dynamic nonlinear behavior. It is also observed that neglecting the size effects results in lower estimates of the PEH vibration amplitudes. The results pave the way for designing new nanoscale sensors in addition to PEHs.

Mediastinal lymph node enlargement on CT scans in idiopathic pulmonary fibrosis

International Nuclear Information System (INIS)

Ahn, Joong Mo; Im, Jung Gi; Yu, Kyu In; Kim, Hyeong Seog; Kim, Dae Young; Yu, Pil Mun

1992-01-01

The increase in size of lymph node on CT scan is the single most important finding of lymphadenopathy. The purpose of this study was to evaluate the size of mediastinal lymph nodes in patients with idiopathic pulmonary fibrosis with no evidence of malignancy or current infection. CT scans of 70 patients (16 with conventional CT and 54 with high-resolution CT) were assessed for lymph node size and location. The duration of symptoms, and the extent and pattern of the parenchymal lung disease on CT scans were correlated with lymph node enlargement. In 54 of 70 patients, more than one lymph nodes were large than 1-1.5 cm. The prevalence of node enlargement increased significant with a longer duration of symptom (p=0.001), large extent of the disease (p=0.043), and with a greater proportion of honeycomb pattern (p=0.033). Right paratracheal, subcarinal, right tracheobronchial, and paraesophageal nodes were the most common sites of node enlargement. In conclusion, mediastinal lymph node enlargement is common in patients with idiopathic pulmonary fibrosis and is more frequently seen in patients with a longer duration of clinical symptoms, greater extent of the disease, and with a larger proportion of honeycomb pattern

Mediastinal lymph node enlargement on CT scans in idiopathic pulmonary fibrosis

Energy Technology Data Exchange (ETDEWEB)

Ahn, Joong Mo; Im, Jung Gi; Yu, Kyu In; Kim, Hyeong Seog [Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Dae Young [Chung Buk National University College of Medicine, Chungju (Korea, Republic of); Yu, Pil Mun [Dankuk University College of Medicine, Seoul (Korea, Republic of)

1992-09-15

The increase in size of lymph node on CT scan is the single most important finding of lymphadenopathy. The purpose of this study was to evaluate the size of mediastinal lymph nodes in patients with idiopathic pulmonary fibrosis with no evidence of malignancy or current infection. CT scans of 70 patients (16 with conventional CT and 54 with high-resolution CT) were assessed for lymph node size and location. The duration of symptoms, and the extent and pattern of the parenchymal lung disease on CT scans were correlated with lymph node enlargement. In 54 of 70 patients, more than one lymph nodes were large than 1-1.5 cm. The prevalence of node enlargement increased significant with a longer duration of symptom (p=0.001), large extent of the disease (p=0.043), and with a greater proportion of honeycomb pattern (p=0.033). Right paratracheal, subcarinal, right tracheobronchial, and paraesophageal nodes were the most common sites of node enlargement. In conclusion, mediastinal lymph node enlargement is common in patients with idiopathic pulmonary fibrosis and is more frequently seen in patients with a longer duration of clinical symptoms, greater extent of the disease, and with a larger proportion of honeycomb pattern.

A local-world node deleting evolving network model

International Nuclear Information System (INIS)

Gu Yuying; Sun Jitao

2008-01-01

A new type network growth rule which comprises node addition with the concept of local-world connectivity and node deleting is studied. A series of theoretical analysis and numerical simulation to the LWD network are conducted in this Letter. Firstly, the degree distribution p(k) of this network changes no longer pure scale free but truncates by an exponential tail and the truncation in p(k) increases as p a decreases. Secondly, the connectivity is tighter, as the local-world size M increases. Thirdly, the average path length L increases and the clustering coefficient decreases as generally node deleting increases. Finally, trends up when the local-world size M increases, so as to k max . Hence, the expanding local-world can compensate the infection of the node deleting

A local-world node deleting evolving network model

Energy Technology Data Exchange (ETDEWEB)

Gu Yuying [Department of Mathematics, Tongji University, Shanghai 200092 (China); Sun Jitao [Department of Mathematics, Tongji University, Shanghai 200092 (China)], E-mail: sunjt@sh163.net

2008-06-16

A new type network growth rule which comprises node addition with the concept of local-world connectivity and node deleting is studied. A series of theoretical analysis and numerical simulation to the LWD network are conducted in this Letter. Firstly, the degree distribution p(k) of this network changes no longer pure scale free but truncates by an exponential tail and the truncation in p(k) increases as p{sub a} decreases. Secondly, the connectivity is tighter, as the local-world size M increases. Thirdly, the average path length L increases and the clustering coefficient decreases as generally node deleting increases. Finally, trends up when the local-world size M increases, so as to k{sub max}. Hence, the expanding local-world can compensate the infection of the node deleting.

Design and development of broadband piezoelectric vibration energy harvester based on compliant orthoplanar spring

Science.gov (United States)

Dhote, Sharvari

With advancement in technology, power requirements are reduced drastically for sensor nodes. The piezoelectric vibration energy harvesters generate sufficient power to low-powered sensor nodes. The main requirement of energy harvester is to provide a broad bandwidth. A conventional linear harvester does not satisfy this requirement. Therefore, the research focus is shifted to exploiting nonlinearity to widen the bandwidth of the harvester. Although nonlinear techniques are promising for broadening a bandwidth, reverse sweep shows reduced response as compared to the forward sweep. To overcome this issue, this thesis presents the design and development of a broadband piezoelectric vibration energy harvester based on a nonlinear multi-frequency compliant orthoplanar spring. This thesis is divided into three parts. The first part presents the design and experimental study of a tri-leg compliant orthoplanar spring for a broadband energy harvesting. The harvester performance is enhanced through the use of lightweight masses, which bring nonlinear vibration modes closer. The performance of the harvester is analyzed through development of a mathematical model based on the Duffing oscillator. The experimental and numerical results are in good agreement. The parametric study shows that an optimum performance is achieved by further reducing a gap in between the vibration modes using different weight masses. In the second part of the research, multiple (bi, quad and pent) leg compliant orthoplanar springs are designed to understand their role in expanding the bandwidth and reducing gap between vibration modes. The designed harvesters are compared by calculating the figure of merits. The quad-leg design provides a better performance in terms of power density and bandwidth among all the designs. The reverse sweep response is comparable to the forward sweep in terms of bandwidth. In the final part, a magnetic force is applied to the tri-leg harvester, which enhanced the voltage

Sizing a rainwater harvesting cistern by minimizing costs

Science.gov (United States)

Pelak, Norman; Porporato, Amilcare

2016-10-01

Rainwater harvesting (RWH) has the potential to reduce water-related costs by providing an alternate source of water, in addition to relieving pressure on public water sources and reducing stormwater runoff. Existing methods for determining the optimal size of the cistern component of a RWH system have various drawbacks, such as specificity to a particular region, dependence on numerical optimization, and/or failure to consider the costs of the system. In this paper a formulation is developed for the optimal cistern volume which incorporates the fixed and distributed costs of a RWH system while also taking into account the random nature of the depth and timing of rainfall, with a focus on RWH to supply domestic, nonpotable uses. With rainfall inputs modeled as a marked Poisson process, and by comparing the costs associated with building a cistern with the costs of externally supplied water, an expression for the optimal cistern volume is found which minimizes the water-related costs. The volume is a function of the roof area, water use rate, climate parameters, and costs of the cistern and of the external water source. This analytically tractable expression makes clear the dependence of the optimal volume on the input parameters. An analysis of the rainfall partitioning also characterizes the efficiency of a particular RWH system configuration and its potential for runoff reduction. The results are compared to the RWH system at the Duke Smart Home in Durham, NC, USA to show how the method could be used in practice.

Effects of physical form and stage of maturity at harvest of whole-crop barley silage on intake, chewing activity, diet selection and faecal particle size of dairy steers

DEFF Research Database (Denmark)

Rustas, B.-O.; Nørgaard, Peder; Jalali, Alireza

2010-01-01

This study examined the effects of physical form and stage of maturity at harvest of whole-crop barley silage (WCBS) on feed intake, eating and rumination activity, diet selection and faecal particle size in dairy steers. Whole-crop barley was harvested and ensiled in round bales. Eight dairy ste...

A self-supporting wireless IoT node that uses kinetic energy harvesting

DEFF Research Database (Denmark)

Lynggaard, Per

2017-01-01

The Internet-of-Things (IoT) is expected to be the next revolution of the internet where trillions of IoT nodes will be deployed on a global scale. It is foreseen that a considerable part of these will be deployed in smart buildings and smart homes where they will provide innovative solutions...

Harvesting-Aware Energy Management for Environmental Monitoring WSN

Directory of Open Access Journals (Sweden)

James Rodway

2017-05-01

Full Text Available Wireless sensor networks can be used to collect data in remote locations, especially when energy harvesting is used to extend the lifetime of individual nodes. However, in order to use the collected energy most effectively, its consumption must be managed. In this work, forecasts of diurnal solar energies were made based on measurements of atmospheric pressure. These forecasts were used as part of an adaptive duty cycling scheme for node level energy management. This management was realized with a fuzzy logic controller that has been tuned using differential evolution. Controllers were created using one and two days of energy forecasts, then simulated in software. These controllers outperformed a human-created reference controller by taking more measurements while using less reserve energy during the simulated period. The energy forecasts were comparable to other available methods, while the method of tuning the fuzzy controller improved overall node performance. The combination of the two is a promising method of energy management.

Development of a piezoelectric based energy harvesting system for autonomous wireless sensor nodes

NARCIS (Netherlands)

Gomez Casseres Espinosa, A.F.; Sanchez Ramirez, Andrea; Combita Alfonso, L.F.; Loendersloot, Richard; Berkhoff, Arthur P.; Le Cam, V.; Mevel, L.; Schoefs, F.

2014-01-01

This paper describes the selection and operation of a Boost Integrated with Flyback Rectifier/Energy storage/DC-DC converter (BIFRED) for piezoelectric energy harvesting purposes. This topology presents features like low-harmonic rectification, energy storage and wide-bandwith voltage control in an

Felling and skidding productivity and harvesting cost in southern pine forests

Science.gov (United States)

R.A. Kluender; B.J. Stokes

1996-01-01

Sixteen stands were harvested at various levels of basal area removed (intensity). Chainsaw felling productivity was more sensitive to stem diameter than harvest intensity. Skidding productivity was highest when removing large trees at high intensity. Harvesting cost was more sensitive to stem size than harvest intensity, although harvest intensity was a very important...

Energy-Efficient Control with Harvesting Predictions for Solar-Powered Wireless Sensor Networks.

Science.gov (United States)

Zou, Tengyue; Lin, Shouying; Feng, Qijie; Chen, Yanlian

2016-01-04

Wireless sensor networks equipped with rechargeable batteries are useful for outdoor environmental monitoring. However, the severe energy constraints of the sensor nodes present major challenges for long-term applications. To achieve sustainability, solar cells can be used to acquire energy from the environment. Unfortunately, the energy supplied by the harvesting system is generally intermittent and considerably influenced by the weather. To improve the energy efficiency and extend the lifetime of the networks, we propose algorithms for harvested energy prediction using environmental shadow detection. Thus, the sensor nodes can adjust their scheduling plans accordingly to best suit their energy production and residual battery levels. Furthermore, we introduce clustering and routing selection methods to optimize the data transmission, and a Bayesian network is used for warning notifications of bottlenecks along the path. The entire system is implemented on a real-time Texas Instruments CC2530 embedded platform, and the experimental results indicate that these mechanisms sustain the networks' activities in an uninterrupted and efficient manner.

Energy-Efficient Control with Harvesting Predictions for Solar-Powered Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Tengyue Zou

2016-01-01

Full Text Available Wireless sensor networks equipped with rechargeable batteries are useful for outdoor environmental monitoring. However, the severe energy constraints of the sensor nodes present major challenges for long-term applications. To achieve sustainability, solar cells can be used to acquire energy from the environment. Unfortunately, the energy supplied by the harvesting system is generally intermittent and considerably influenced by the weather. To improve the energy efficiency and extend the lifetime of the networks, we propose algorithms for harvested energy prediction using environmental shadow detection. Thus, the sensor nodes can adjust their scheduling plans accordingly to best suit their energy production and residual battery levels. Furthermore, we introduce clustering and routing selection methods to optimize the data transmission, and a Bayesian network is used for warning notifications of bottlenecks along the path. The entire system is implemented on a real-time Texas Instruments CC2530 embedded platform, and the experimental results indicate that these mechanisms sustain the networks’ activities in an uninterrupted and efficient manner.

Search for an optimal colloid for sentinel node imaging

International Nuclear Information System (INIS)

Imam, S.K.; Killingsworth, M.

2005-01-01

This study aims at finding a cost-effective and stable colloid of appropriate size to replace antimony sulfide colloid which is now in routine use in Australia for sentinel lymph node (SLN) imaging. For this reason we evaluated three colloids; namely phytate, hepatate and stannous fluoride (SnF 2 ). As colloids of particle size of 100-200 nm seem to be appropriate for sentinel node imaging, the three radiolabelled colloid preparations were filtered through 0.1 and 0.22 μm filters and then studied on electron microscope. Electron microscopy showed that unlike phytate, the particle size of the hepatate and SnF 2 colloids did not increase beyond the size limit of 200 nm over a period of as long as 26 hours. Instead, they remained well within the size limits chosen. The stability of particle size is required for intra-operative gamma probe lymphatic mapping that sometimes may be performed on the following day. Hepatate and SnF 2 colloids appeared to be more suited for sentinel lymph node imaging, the latter being an inhouse product is more cost-effective. Further studies based on nodal uptake and the behavior of these two radiopharmaceuticals in animals is suggested in order to evaluate their potential for future wide-spread application in human sentinel node imaging. (author)

High risk of non-sentinel node metastases in a group of breast cancer patients with micrometastases in the sentinel node.

Science.gov (United States)

Tvedskov, Tove Filtenborg; Jensen, Maj-Britt; Lisse, Ida Marie; Ejlertsen, Bent; Balslev, Eva; Kroman, Niels

2012-11-15

Axillary lymph node dissection (ALND) in breast cancer patients with positive sentinel nodes is under debate. We aimed to establish two models to predict non-sentinel node (NSN) metastases in patients with micrometastases or isolated tumor cells (ITC) in sentinel nodes, to guide the decision for ALND. A total of 1,577 breast cancer patients with micrometastases and 304 with ITC in sentinel nodes, treated by sentinel lymph node dissection and ALND in 2002-2008 were identified in the Danish Breast Cancer Cooperative Group database. Risk of NSN metastases was calculated according to clinicopathological variables in a logistic regression analysis. We identified tumor size, proportion of positive sentinel nodes, lymphovascular invasion, hormone receptor status and location of tumor in upper lateral quadrant of the breast as risk factors for NSN metastases in patients with micrometastases. A model based on these risk factors identified 5% of patients with a risk of NSN metastases on nearly 40%. The model was however unable to identify a subgroup of patients with a very low risk of NSN metastases. Among patients with ITC, we identified tumor size, age and proportion of positive sentinel nodes as risk factors. A model based on these risk factors identified 32% of patients with risk of NSN metastases on only 2%. Omission of ALND would be acceptable in this group of patients. In contrast, ALND may still be beneficial in the subgroup of patients with micrometastases and a high risk of NSN metastases. Copyright © 2012 UICC.

Vibration energy harvesting using the Halbach array

International Nuclear Information System (INIS)

Zhu, Dibin; Beeby, Steve; Tudor, John; Harris, Nick

2012-01-01

This paper studies the feasibility of vibration energy harvesting using a Halbach array. A Halbach array is a specific arrangement of permanent magnets that concentrates the magnetic field on one side of the array while cancelling the field to almost zero on the other side. This arrangement can improve electromagnetic coupling in a limited space. The Halbach array offers an advantage over conventional layouts of magnets in terms of its concentrated magnetic field and low-profile structure, which helps improve the output power of electromagnetic energy harvesters while minimizing their size. Another benefit of the Halbach array is that due to the existence of an almost-zero magnetic field zone, electronic components can be placed close to the energy harvester without any chance of interference, which can potentially reduce the overall size of a self-powered device. The first reported example of a low-profile, planar electromagnetic vibration energy harvester utilizing a Halbach array was built and tested. Results were compared to ones for energy harvesters with conventional magnet layouts. By comparison, it is concluded that although energy harvesters with a Halbach array can have higher magnetic field density, a higher output power requires careful design in order to achieve the maximum magnetic flux gradient. (paper)

Aeroelastic flutter energy harvesters self-polarized by triboelectric effects

Science.gov (United States)

Perez, M.; Boisseau, S.; Geisler, M.; Gasnier, P.; Willemin, J.; Despesse, G.; Reboud, J. L.

2018-01-01

This paper presents the performances of several electrostatic flutter energy harvesters tested in a wind tunnel between 0 and 20 m s-1. The main idea is to use the flutter capability of thin flexible films confined between lateral walls to induce simultaneously the capacitance variations and the electrostatic polarization required by the triboelectric/electrostatic conversion. This technology provides thin and flexible devices and solve the electret’s stability issue (Perez et al 2015 Smart Mater. Struct., Perez et al 2015 New Circuits and Systems). Our prototypes (management circuit has finally been used to supply an 868 MHz wireless sensor node with temperature and acceleration measurements, validating the complete energy harvesting chain.

Flow Energy Piezoelectric Bimorph Nozzle Harvester

Science.gov (United States)

Sherrit, Stewart (Inventor); Walkemeyer, Phillip E. (Inventor); Hall, Jeffrey L. (Inventor); Lee, Hyeong Jae (Inventor); Colonius, Tim (Inventor); Tosi, Phillipe (Inventor); Kim, Namhyo (Inventor); Sun, Kai (Inventor); Corbett, Thomas Gary (Inventor); Arrazola, Alvaro Jose (Inventor)

2016-01-01

A flow energy harvesting device having a harvester pipe includes a flow inlet that receives flow from a primary pipe, a flow outlet that returns the flow into the primary pipe, and a flow diverter within the harvester pipe having an inlet section coupled to the flow inlet, a flow constriction section coupled to the inlet section and positioned at a midpoint of the harvester pipe and having a spline shape with a substantially reduced flow opening size at a constriction point along the spline shape, and an outlet section coupled to the constriction section. The harvester pipe may further include a piezoelectric structure extending from the inlet section through the constriction section and point such that the fluid flow past the constriction point results in oscillatory pressure amplitude inducing vibrations in the piezoelectric structure sufficient to cause a direct piezoelectric effect and to generate electrical power for harvesting.

Comparison of tree size structure and growth for partially harvested and even-aged hemlock-spruce stands in southeast Alaska

Science.gov (United States)

Robert L. Deal; Troy Heithecker; Eric K. Zenner

2010-01-01

The effects of partial cutting on tree size structure and stand growth were evaluated in 52 plots in 13 stands in southeast Alaska that were partially harvested 53 to 96 years ago and compared with 50-year-old even-aged stands that developed after clearcutting. The net basal-area growth was greater in the partially cut plots than in the uncut plots, and basal-area...

Suppressing epidemics on networks by exploiting observer nodes.

Science.gov (United States)

Takaguchi, Taro; Hasegawa, Takehisa; Yoshida, Yuichi

2014-07-01

To control infection spreading on networks, we investigate the effect of observer nodes that recognize infection in a neighboring node and make the rest of the neighbor nodes immune. We numerically show that random placement of observer nodes works better on networks with clustering than on locally treelike networks, implying that our model is promising for realistic social networks. The efficiency of several heuristic schemes for observer placement is also examined for synthetic and empirical networks. In parallel with numerical simulations of epidemic dynamics, we also show that the effect of observer placement can be assessed by the size of the largest connected component of networks remaining after removing observer nodes and links between their neighboring nodes.

Suppressing epidemics on networks by exploiting observer nodes

Science.gov (United States)

Takaguchi, Taro; Hasegawa, Takehisa; Yoshida, Yuichi

2014-07-01

To control infection spreading on networks, we investigate the effect of observer nodes that recognize infection in a neighboring node and make the rest of the neighbor nodes immune. We numerically show that random placement of observer nodes works better on networks with clustering than on locally treelike networks, implying that our model is promising for realistic social networks. The efficiency of several heuristic schemes for observer placement is also examined for synthetic and empirical networks. In parallel with numerical simulations of epidemic dynamics, we also show that the effect of observer placement can be assessed by the size of the largest connected component of networks remaining after removing observer nodes and links between their neighboring nodes.

331 cases of clinically node-negative supraglottic carcinoma of the larynx: a study of a modest size fixed field radiotherapy approach

International Nuclear Information System (INIS)

Sykes, Andrew J.; Slevin, Nicholas J.; Gupta, Nirmal K.; Brewster, Allison E.

2000-01-01

Purpose: For node-negative supraglottic carcinoma of the larynx, radiotherapy with surgery in reserve commonly provides very good results in terms of both local control and survival, while preserving function. However uncertainty exists over the treatment of the node-negative neck. Elective whole neck radiotherapy, while effective, may be associated with significant morbidity. The purpose of this study was to examine our practice of treating a modest size, fixed field to a high biologically effective dose and compare it with the patterns of recurrence from other centers that use different dose/volume approaches. Methods and Materials: Over a 10-year period 331 patients with node-negative supraglottic carcinoma of the larynx were treated with radiotherapy at the Christie Hospital Manchester. Patients were treated with doses of 50-55 Gy in 16 fractions over 3 weeks. Data were collected retrospectively for local and regional control, survival, and morbidity. Results: Overall local control, after surgical salvage in 17 cases, was 79% (T1-92%, T2-81%, T3-67%, T4-73%). Overall regional lymph node control, after surgical salvage in 13 cases, was 84% (T1-91%, T2-88%, T3-81%, T4-72%). Five-year crude survival was 50%, but after correcting for intercurrent deaths was 70% (T1-83%, T2-78%, T3-53%, T4-61%). Serious morbidity requiring surgery was seen in 7 cases (2.1%) and was related to prescribed dose (50 Gy-0%, 52.5 Gy-1.3%, 55 Gy-3.4%). Discussion: Our results confirm that treating a modest size, fixed field to a high biologically effective dose is highly effective. It enables preservation of the larynx in most cases, with acceptable regional control and no loss of survival compared to whole neck radiotherapy regimes

Lymph node detection in IASLC-defined zones on PET/CT images

Science.gov (United States)

Song, Yihua; Udupa, Jayaram K.; Odhner, Dewey; Tong, Yubing; Torigian, Drew A.

2016-03-01

Lymph node detection is challenging due to the low contrast between lymph nodes as well as surrounding soft tissues and the variation in nodal size and shape. In this paper, we propose several novel ideas which are combined into a system to operate on positron emission tomography/ computed tomography (PET/CT) images to detect abnormal thoracic nodes. First, our previous Automatic Anatomy Recognition (AAR) approach is modified where lymph node zones predominantly following International Association for the Study of Lung Cancer (IASLC) specifications are modeled as objects arranged in a hierarchy along with key anatomic anchor objects. This fuzzy anatomy model built from diagnostic CT images is then deployed on PET/CT images for automatically recognizing the zones. A novel globular filter (g-filter) to detect blob-like objects over a specified range of sizes is designed to detect the most likely locations and sizes of diseased nodes. Abnormal nodes within each automatically localized zone are subsequently detected via combined use of different items of information at various scales: lymph node zone model poses found at recognition indicating the geographic layout at the global level of node clusters, g-filter response which hones in on and carefully selects node-like globular objects at the node level, and CT and PET gray value but within only the most plausible nodal regions for node presence at the voxel level. The models are built from 25 diagnostic CT scans and refined for an object hierarchy based on a separate set of 20 diagnostic CT scans. Node detection is tested on an additional set of 20 PET/CT scans. Our preliminary results indicate node detection sensitivity and specificity at around 90% and 85%, respectively.

Comparison of 99mTc-MIBI scanning and sentinel node biopsy in the detection of occult melanoma lymph node metastases

International Nuclear Information System (INIS)

Alonso, O.; Lago, G.; Lopes de Amorim, M.C.; Juri, C.; Larre Borges, A.; Martinez, M.; De Boni, D.; Espasandin, J.; Priario, J.

2002-01-01

Aim: Sentinel node biopsy (SNB) is a highly accurate technique for detecting occult metastatic disease in the regional lymph nodes. Our group has reported that 99m Tc-MIBI scintigraphy is an imaging technique that can detect clinically undetectable metastases. This prospective study shows preliminary results on the comparison of both techniques for the detection of lymph node invasion. Material and Methods: Twenty-two consecutive patients (15 women, 7 men; mean age, 55 years) with primary melanoma > 1.0 mm thick were enrolled (mean 2.6 mm). Patients underwent 99m Tc-MIBI scintigraphy of regional lymph nodes 1-2 weeks before surgery, acquiring 10-minute planar images with a LFOV gamma camera. A preoperative lymphoscintigraphy using 99m Tc-colloidal (Re) sulphide was performed the day before surgery, using a dose of 74-93 MBq. Radio guided SNB was performed with a hand-held gamma probe. Lymph nodes were examined histologically and immunostained for S-100 and HMB-45. Results: The sentinel node (SN) was identified in 21/22 patients. An average of 1.6 SN/lesion were harvested from melanomas located in the following regions: head and neck (n=3), trunk (n=6), extremities (n=12). All patients with negative SN (n=11) were also negative with MIBI. In 10 cases the SN demonstrated metastatic involvement, whereas 99m Tc-MIBI was positive in 8 of them (80%). In cases with positive SN/negative 99m Tc-MIBI, the pathology report revealed micro metastatic disease. Conclusion: These preliminary results suggest that 99m Tc-MIBI scanning has the potential of selecting a group of patients who might benefit from a selective complete lymphadenectomy

An Energy-Efficient Scheme for Multirelay Cooperative Networks with Energy Harvesting

Directory of Open Access Journals (Sweden)

Dingcheng Yang

2016-01-01

Full Text Available This study investigates an energy-efficient scheme in multirelay cooperative networks with energy harvesting where multiple sessions need to communicate with each other via the relay node. A two-step optimal method is proposed which maximizes the system energy efficiency, while taking into account the receiver circuit energy consumption. Firstly, the optimal power allocation for relay nodes is determined to maximize the system throughput; this is based on directional water-filling algorithm. Secondly, using quantum particle swarm optimization (QPSO, a joint relay node selection and session grouping optimization is proposed. With this algorithm, sessions can be classified into multiple groups that are assisted by the specific relay node with the maximum energy efficiency. This approach leads to a better global optimization in searching ability and efficiency. Simulation results show that the proposed scheme can improve the energy efficiency effectively compared with direct transmission and opportunistic relay-selected cooperative transmission.

Experimental studies of metastases of esophageal carcinoma to lymph nodes

International Nuclear Information System (INIS)

Inoue, Kazumasa

1977-01-01

Marked progress has been made in surgery for esophageal carcinoma, however, when compared to results of surgery for other carcinomas of the digestive tract, much research remains to be done. The author transplanted VX2 carcinoma, a transplantable tumor of the rabbit, to the esophagus in attempt to determine the mode of metastases of esophageal carcinoma to lymph nodes and also to observe the effect of chemotherapy (Bleomycin) and radiotherapy (Betatron). Carcinoma of the cervical esophagus metastasized to the cervical lymph nodes and then to the paratracheal lymph nodes. Carcinoma of the upper thoracic esophagus metastasized to the paratracheal lymph nodes and then to the cervical lymph nodes. Carcinoma of the mid-thoracic esophagus metastasized to the intrathoracic lymph nodes and then to the intraperitoneal lymph nodes. Carcinoma of the abdominal esophagus metastasized to the intraperitoneal lymph nodes and then to the intrathoracic lymph nodes. Skipping metastasis was rarely observed. Carcinoma of the thoracic esophagus with metastases of lymph nodes in the cervical or abdominal portion was considerably advanced, therefore it is considered that cleaning of the intrathoracic lymph nodes and simultaneous chemotherapy are required when such cases are encountered clinically. Irradiation resulted in regression in the size of the tumor and metastases to lymph nodes and there was a decrease in metastases to the distant lymph nodes. Effects of irradiation were similar on tumors and lymph nodes with positive metastases located within the field of irradiation. Bleomycin medication resulted in regression in the size of tumor and metastases to lymph nodes. Effects of Bleomycin medication were similar on tumors and lymph nodes with positive metastases. (auth.)

Lung, liver and lymph node metastases in follow-up MSCT. Comprehensive volumetric assessment of lesion size changes

International Nuclear Information System (INIS)

Wulff, A.M.; Fischer, S.; Biederer, J.; Heller, M.; Fabel, M.; Bolte, H.; Freitag-Wolf, S.; Soza, G.; Tietjen, C.

2012-01-01

Purpose: To investigate measurement accuracy in terms of precision and inter-rater variability in the simultaneous volumetric assessment of lung, liver and lymph node metastasis size change over time in comparison to RECIST 1.1. Materials and Methods: Three independent readers evaluated multislice CT data from clinical follow-up studies (chest/abdomen) in 50 patients with metastases. A total of 117 lung, 77 liver and 97 lymph node metastases were assessed manually (RECIST 1.1) and by volumetry with semi-automated software. The quality of segmentation and need for manual adjustments were recorded. Volumes were converted to effective diameters to allow comparison to RECIST. For statistical assessment of precision and interobserver agreement, the Wilcoxon-signed rank test and Bland-Altman plots were utilized. Results: The quality of segmentation after manual correction was acceptable to excellent in 95 % of lesions and manual corrections were applied in 21 - 36 % of all lesions, most predominantly in lymph nodes. Mean precision was 2.6 - 6.3 % (manual) with 0.2 - 1.5 % (effective) relative measurement deviation (p <.001). Inter-reader median variation coefficients ranged from 9.4 - 12.8 % (manual) and 2.9 - 8.2 % (volumetric) for different lesion types (p <.001). The limits of agreement were ± 9.8 to ± 11.2 % for volumetric assessment. Conclusion: Superior precision and inter-rater variability of volumetric over manual measurement of lesion change over time was demonstrated in a whole body setting. (orig.)

Lung, liver and lymph node metastases in follow-up MSCT. Comprehensive volumetric assessment of lesion size changes

Energy Technology Data Exchange (ETDEWEB)

Wulff, A.M.; Fischer, S.; Biederer, J.; Heller, M.; Fabel, M. [Universitaetsklinikum Schleswig-Holstein, Kiel (Germany). Klinik fuer Diagnostische Radiologie; Bolte, H. [Universitaetsklinikum Muenster (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Freitag-Wolf, S. [Universitaetsklinikum Schleswig-Holstein, Kiel (Germany). Inst. fuer Medizinische Informatik und Statistik; Soza, G.; Tietjen, C. [Siemens AG (Germany). Imaging and IT Div. Computed Tomography

2012-09-15

Purpose: To investigate measurement accuracy in terms of precision and inter-rater variability in the simultaneous volumetric assessment of lung, liver and lymph node metastasis size change over time in comparison to RECIST 1.1. Materials and Methods: Three independent readers evaluated multislice CT data from clinical follow-up studies (chest/abdomen) in 50 patients with metastases. A total of 117 lung, 77 liver and 97 lymph node metastases were assessed manually (RECIST 1.1) and by volumetry with semi-automated software. The quality of segmentation and need for manual adjustments were recorded. Volumes were converted to effective diameters to allow comparison to RECIST. For statistical assessment of precision and interobserver agreement, the Wilcoxon-signed rank test and Bland-Altman plots were utilized. Results: The quality of segmentation after manual correction was acceptable to excellent in 95 % of lesions and manual corrections were applied in 21 - 36 % of all lesions, most predominantly in lymph nodes. Mean precision was 2.6 - 6.3 % (manual) with 0.2 - 1.5 % (effective) relative measurement deviation (p <.001). Inter-reader median variation coefficients ranged from 9.4 - 12.8 % (manual) and 2.9 - 8.2 % (volumetric) for different lesion types (p <.001). The limits of agreement were {+-} 9.8 to {+-} 11.2 % for volumetric assessment. Conclusion: Superior precision and inter-rater variability of volumetric over manual measurement of lesion change over time was demonstrated in a whole body setting. (orig.)

The relation between lymph node status and survival in Stage I-III colon cancer

DEFF Research Database (Denmark)

Lykke, J.; Roikjær, Ole; Jess, P.

2013-01-01

Aim: This study involved a large nationwide Danish cohort to evaluate the hypothesis that a high lymph node harvest has a positive effect on survival in curative resected Stage I-III colon cancer and a low lymph node ratio has a positive effect on survival in Stage III colon cancer. Method......: Analysis of overall survival was conducted using a nationwide Danish cohort of patients treated with curative resection of Stage I-III colon cancer. All 8901 patients in Denmark diagnosed with adenocarcinoma of the colon and treated with curative resection in the period 2003-2008 were identified from...... independent prognostic factors in multivariate analysis. Conclusion: High lymph node count was associated with improved overall survival in colon cancer. Lymph node ratio was superior to N-stage in differentiating overall survival in Stage III colon cancer. Stage migration was observed....

Macroscopic description of complex adaptive networks coevolving with dynamic node states

Science.gov (United States)

Wiedermann, Marc; Donges, Jonathan F.; Heitzig, Jobst; Lucht, Wolfgang; Kurths, Jürgen

2015-05-01

In many real-world complex systems, the time evolution of the network's structure and the dynamic state of its nodes are closely entangled. Here we study opinion formation and imitation on an adaptive complex network which is dependent on the individual dynamic state of each node and vice versa to model the coevolution of renewable resources with the dynamics of harvesting agents on a social network. The adaptive voter model is coupled to a set of identical logistic growth models and we mainly find that, in such systems, the rate of interactions between nodes as well as the adaptive rewiring probability are crucial parameters for controlling the sustainability of the system's equilibrium state. We derive a macroscopic description of the system in terms of ordinary differential equations which provides a general framework to model and quantify the influence of single node dynamics on the macroscopic state of the network. The thus obtained framework is applicable to many fields of study, such as epidemic spreading, opinion formation, or socioecological modeling.

Efficient Graph Computation for Node2Vec

OpenAIRE

Zhou, Dongyan; Niu, Songjie; Chen, Shimin

2018-01-01

Node2Vec is a state-of-the-art general-purpose feature learning method for network analysis. However, current solutions cannot run Node2Vec on large-scale graphs with billions of vertices and edges, which are common in real-world applications. The existing distributed Node2Vec on Spark incurs significant space and time overhead. It runs out of memory even for mid-sized graphs with millions of vertices. Moreover, it considers at most 30 edges for every vertex in generating random walks, causin...

Effect of harvest time of red and white clover silage on chewing activity and particle size distribution in boli, rumen content and faeces in cows.

Science.gov (United States)

Kornfelt, L F; Nørgaard, P; Weisbjerg, M R

2013-06-01

The study examined the effects of harvest time of red and white clover silage on eating and ruminating activity and particle size distribution in feed boli, rumen content and faeces in cows. The clover crops were harvested at two stages of growth and ensiled in bales. Red clover crops had 36% and 45% NDF in dry matter (DM) at early (ER) and late (LR) harvest, respectively, and the white clover crops had 19% and 29% NDF in DM at the early (EW) and late (LW) harvest, respectively. The silages were fed restrictively (80% of ad libitum intake) twice daily to four rumen cannulated non-lactating Jersey cows (588 ± 52 kg) in a 4 × 4 Latin square design. Jaw movements (JM) were recorded for 96 h continuously. Swallowed boli, rumen mat, rumen fluid and faeces samples were collected, washed in nylon bags (0.01 mm pore size) and freeze-dried before dry sieving through 4.750, 2.360, 1.000, 0.500, 0.212 and 0.106 mm into seven fractions. The length (PL) and width (PW) values of rumen and faeces particles within each fraction were measured by use of image analysis. The eating activity (min/kg DM intake; P rumen mat (P rumen fluid (P rumen mat and faeces, but only one peak (mode 1) for PL values. There was no difference in the mean and mode 1 PW and PL value in rumen mat between the four treatments. The mean PL, mode PL, mode 2 PW and mean PW in faeces were highest for LR (P rumen mat and faeces particles are most likely related to the leaves and the stems/petioles. In conclusion, the mean total chewing activity per kg DM was lowest for the white clover silage and increased for both silages due to later harvest time. The mean particle size in boli was smallest for LR, whereas the mean PL and PW in faeces were highest for the LR.

The effects of harvest on waterfowl populations

Science.gov (United States)

Cooch, Evan G.; Guillemain, Matthieu; Boomer, G Scott; Lebreton, Jean-Dominique; Nichols, James D.

2014-01-01

Change in the size of populations over space and time is, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change in the abundance is the simple difference between the number of individuals entering the population and the number leaving the population, either or both of which may change in response to factors intrinsic and extrinsic to the population. While harvest of individuals from a population constitutes a clear extrinsic source of removal of individuals, the response of populations to harvest is frequently complex, reflecting an interaction of harvest with one or more population processes. Here we consider the role of these interactions, and factors influencing them, on the effective harvest management of waterfowl populations. We review historical ideas concerning harvest and discuss the relationship(s) between waterfowl life histories and the development and application of population models to inform harvest management. The influence of population structure (age, spatial) on derivation of optimal harvest strategies (with and without explicit consideration of various sources of uncertainty) is considered. In addition to population structure, we discuss how the optimal harvest strategy may be influenced by: 1) patterns of density-dependence in one or more vital rates, and 2) heterogeneity in vital rates among individuals within an age-sex-size class. Although derivation of the optimal harvest strategy for simple population models (with or without structure) is generally straightforward, there are several potential difficulties in application. In particular, uncertainty concerning the population structure at the time of harvest, and the ability to regulate the structure of the harvest itself, are significant complications. We therefore review the evidence of effects of harvest on waterfowl populations. Some of this evidence has

Three faces of node importance in network epidemiology: Exact results for small graphs

Science.gov (United States)

Holme, Petter

2017-12-01

We investigate three aspects of the importance of nodes with respect to susceptible-infectious-removed (SIR) disease dynamics: influence maximization (the expected outbreak size given a set of seed nodes), the effect of vaccination (how much deleting nodes would reduce the expected outbreak size), and sentinel surveillance (how early an outbreak could be detected with sensors at a set of nodes). We calculate the exact expressions of these quantities, as functions of the SIR parameters, for all connected graphs of three to seven nodes. We obtain the smallest graphs where the optimal node sets are not overlapping. We find that (i) node separation is more important than centrality for more than one active node, (ii) vaccination and influence maximization are the most different aspects of importance, and (iii) the three aspects are more similar when the infection rate is low.

On-Demand Sensor Node Wake-Up Using Solar Panels and Visible Light Communication

Directory of Open Access Journals (Sweden)

Carolina Carrascal

2016-03-01

Full Text Available To significantly reduce, or eliminate completely, the energy waste caused by the standby (idle mode of wireless sensor nodes, we propose a novel on-demand wake-up system, which allows the nodes to be put into sleep mode unless their activation is truly necessary. Although there have been many studies proposing RF-based wake-up radio systems, in this work, we develop the first visible light communication (VLC-based wake-up system. The developed system can extend the existing VLC systems and can be exploited to derive new application areas such as VLC tags. The system uses an off-the-shell indoor solar panel as receptor device of the wake-up signal as well as for energy harvesting purposes, through which it is able to harvest enough energy for its autonomous work. The design, implementation details and the experimental evaluation results are presented, which include flickering characterization and wake-up range evaluations. The results show that the developed system achieve reasonable wake-up distances for indoor environments, mainly where the use of VLC systems are considered.

On-Demand Sensor Node Wake-Up Using Solar Panels and Visible Light Communication.

Science.gov (United States)

Carrascal, Carolina; Demirkol, Ilker; Paradells, Josep

2016-03-22

To significantly reduce, or eliminate completely, the energy waste caused by the standby (idle) mode of wireless sensor nodes, we propose a novel on-demand wake-up system, which allows the nodes to be put into sleep mode unless their activation is truly necessary. Although there have been many studies proposing RF-based wake-up radio systems, in this work, we develop the first visible light communication (VLC)-based wake-up system. The developed system can extend the existing VLC systems and can be exploited to derive new application areas such as VLC tags. The system uses an off-the-shell indoor solar panel as receptor device of the wake-up signal as well as for energy harvesting purposes, through which it is able to harvest enough energy for its autonomous work. The design, implementation details and the experimental evaluation results are presented, which include flickering characterization and wake-up range evaluations. The results show that the developed system achieve reasonable wake-up distances for indoor environments, mainly where the use of VLC systems are considered.

Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester

Directory of Open Access Journals (Sweden)

Ali E. Kubba

2013-12-01

Full Text Available Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA was used as an initial tool to compare the three geometries’ stiffness (K, output open-circuit voltage (Vave, and average normal strain in the piezoelectric transducer (εave that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3, has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle.

West Virginia harvest and utilization study, 2008

Science.gov (United States)

Jan Wiedenbeck; Shawn. Grushecky

2014-01-01

Thirty active harvesting operations were part of a harvest and utilization study conducted in West Virginia in 2008. Data were collected on roundwood product and residue yields obtained from trees of different sizes, species, and qualities. This study was modeled after studies conducted on a regular and frequent basis by the Forest Inventory and Analysis unit in the...

Learning and adaptation in the management of waterfowl harvests

Science.gov (United States)

Johnson, Fred A.

2011-01-01

A formal framework for the adaptive management of waterfowl harvests was adopted by the U.S. Fish and Wildlife Service in 1995. The process admits competing models of waterfowl population dynamics and harvest impacts, and relies on model averaging to compute optimal strategies for regulating harvest. Model weights, reflecting the relative ability of the alternative models to predict changes in population size, are used in the model averaging and are updated each year based on a comparison of model predictions and observations of population size. Since its inception the adaptive harvest program has focused principally on mallards (Anas platyrhynchos), which constitute a large portion of the U.S. waterfowl harvest. Four competing models, derived from a combination of two survival and two reproductive hypotheses, were originally assigned equal weights. In the last year of available information (2007), model weights favored the weakly density-dependent reproductive hypothesis over the strongly density-dependent one, and the additive mortality hypothesis over the compensatory one. The change in model weights led to a more conservative harvesting policy than what was in effect in the early years of the program. Adaptive harvest management has been successful in many ways, but nonetheless has exposed the difficulties in defining management objectives, in predicting and regulating harvests, and in coping with the tradeoffs inherent in managing multiple waterfowl stocks exposed to a common harvest. The key challenge now facing managers is whether adaptive harvest management as an institution can be sufficiently adaptive, and whether the knowledge and experience gained from the process can be reflected in higher-level policy decisions.

The significance of a uniform definition of pathological lymph nodes in Hodgkin lymphoma: Impact of different thresholds for positive lymph nodes in CT imaging on staging and therapy

International Nuclear Information System (INIS)

Vorwerk, Hilke; Obenauer, Silvia; Schmidberger, Heinz; Hess, Clemens F.; Weiss, Elisabeth

2008-01-01

Background and Purpose: The most commonly used approach for the assessment for differentiating malignant versus reactive lymph nodes is the measurement of the cross-section diameter of the lymph nodes in the transversal CT-planes. The intention of this article is to assess the impact of varying definitions of pathological lymph node size in CT-imaging in patients with Hodgkin lymphoma and to evaluate its effect on staging, chemotherapy regimes and radiation field size. Materials and methods: Pretherapeutic CT-scans of 10 consecutive patients with Hodgkin lymphoma have been evaluated based on two different definitions for malignant lymph node size; the classification of the German study group for Hodgkin lymphoma (1.0 cm) and the classification according to the results of the Cotswold consensus meeting 1989 (1.5 cm). Results: Applying the definitions of the DHSG and the Cotswold meeting we found more affected lymph node regions compared to the evaluation of the referring institutions in 9/10 and 6/10 patients, higher stages in 2/10 and 1/10 patients, more intense chemotherapy regimes in 3/10 and 1/10 and larger radiation fields in 10/10 and 6/10 patients, respectively. Conclusions: Varying definitions of pathologic lymph node size and inconsequent application of definitions reduce the comparability between different studies and within each study

An Autonomous Wireless Sensor Node With Asynchronous ECG Monitoring in 0.18 μ m CMOS.

Science.gov (United States)

Mansano, Andre L; Li, Yongjia; Bagga, Sumit; Serdijn, Wouter A

2016-06-01

The design of a 13.56 MHz/402 MHz autonomous wireless sensor node with asynchronous ECG monitoring for near field communication is presented. The sensor node consists of an RF energy harvester (RFEH), a power management unit, an ECG readout, a data encoder and an RF backscattering transmitter. The energy harvester supplies the system with 1.25 V and offers a power conversion efficiency of 19% from a -13 dBm RF source at 13.56 MHz. The power management unit regulates the output voltage of the RFEH to supply the ECG readout with VECG = 0.95 V and the data encoder with VDE = 0.65 V . The ECG readout comprises an analog front-end (low noise amplifier and programmable voltage to current converter) and an asynchronous level crossing ADC with 8 bits resolution. The ADC output is encoded by a pulse generator that drives a backscattering transmitter at 402 MHz. The total power consumption of the sensor node circuitry is 9.7 μ W for a data rate of 90 kb/s and a heart rate of 70 bpm. The chip has been designed in a 0.18 μm CMOS process and shows superior RF input power sensitivity and lower power consumption when compared to previous works.

Resource aware sensor nodes in wireless sensor networks

International Nuclear Information System (INIS)

Merrett, G V; Al-Hashimi, B M; White, N M; Harris, N R

2005-01-01

Wireless sensor networks are continuing to receive considerable research interest due, in part, to the range of possible applications. One of the greatest challenges facing researchers is in overcoming the limited network lifetime inherent in the small locally powered sensor nodes. In this paper, we propose IDEALS, a system to manage a wireless sensor network using a combination of information management, energy harvesting and energy monitoring, which we label resource awareness. Through this, IDEALS is able to extend the network lifetime for important messages, by controlling the degradation of the network to maximise information throughput

On Secure Underlay MIMO Cognitive Radio Networks with Energy Harvesting and Transmit Antenna Selection

KAUST Repository

Lei, Hongjiang

2017-03-20

In this paper, we consider an underlay multipleinput- multiple-output (MIMO) cognitive radio network (CRN) including a pair of primary nodes, a couple of secondary nodes, and an eavesdropper, where the secondary transmitter is powered by the renewable energy harvested from the primary transmitter in order to improve both energy efficiency and spectral efficiency. Based on whether the channel state information (CSI) of wiretap links are available or not, the secrecy outage performance of the optimal antenna selection (OAS) scheme and suboptimal antenna selection (SAS) scheme for underlay MIMO CRN with energy harvesting are investigated and compared with traditional space-time transmission scheme. The closed-form expressions for exact and asymptotic secrecy outage probability are derived. Monte-Carlo simulations are conducted to testify the accuracy of the analytical results. The analysis illustrates that OAS scheme outperforms SAS scheme. Furthermore, the asymptotic result shows that no matter which scheme is considered, the OAS and SAS schemes can achieve the same secrecy diversity order.

Photoacoustic imaging of human lymph nodes with endogenous lipid and hemoglobin contrast

Science.gov (United States)

Guggenheim, James A.; Allen, Thomas J.; Plumb, Andrew; Zhang, Edward Z.; Rodriguez-Justo, Manuel; Punwani, Shonit; Beard, Paul C.

2015-05-01

Lymph nodes play a central role in metastatic cancer spread and are a key clinical assessment target. Abnormal node vascularization, morphology, and size may be indicative of disease but can be difficult to visualize with sufficient accuracy using existing clinical imaging modalities. To explore the potential utility of photoacoustic imaging for the assessment of lymph nodes, images of ex vivo samples were obtained at multiple wavelengths using a high-resolution three-dimensional photoacoustic scanner. These images showed that hemoglobin based contrast reveals nodal vasculature and lipid-based contrast reveals the exterior node size, shape, and boundary integrity. These two sources of complementary contrast may allow indirect observation of cancer, suggesting a future role for photoacoustic imaging as a tool for the clinical assessment of lymph nodes.

Polychlorinated Biphenyl Levels and its Correlation to Size of Marine Organisms Harvested from a War-Induced Oil Spill Zone of the Eastern Mediterranean Sea

Directory of Open Access Journals (Sweden)

E.K. BARBOUR

2009-12-01

Full Text Available This is the first work establishing a base-line data of the level of total Polychlorinated Biphenyl (PCB contaminants in selected marine organisms (Siganus rivulatus, Mullet spp., and oysters and its relationship to organism size and the harvest distance from the oil spill source. Six locations across the Lebanese Mediterranean were included for sampling. Oysters and the two fish types were collected after 72 days of the spill. The length, maximum width, and whole weight of individual organisms were recorded. Methanol extracts of the samples were analyzed for total PCB using a Competitive Enzyme-linked Immunosorbent Assay (ELISA based Spectrophotometry.All means of PCB in the three selected marine organisms were below the guidance level set by USFDA (2 ppm. A total of 6 significant regression equations were established between the total PCB level and certain size dimensions of specific selected marine species, with values of R2 ranging between 0.719 – 0.909 and P values ranging from 0.038 – 0.099.In addition, the total PCB level in Siganus rivulatus correlated with the harvest distance north of the oil spill source, signifying a drop in total PCB level with an increase in harvest distance from the oil spill source.

Predictive Factors for Nonsentinel Lymph Node Metastasis in Patients With Positive Sentinel Lymph Nodes After Neoadjuvant Chemotherapy: Nomogram for Predicting Nonsentinel Lymph Node Metastasis.

Science.gov (United States)

Ryu, Jai Min; Lee, Se Kyung; Kim, Ji Young; Yu, Jonghan; Kim, Seok Won; Lee, Jeong Eon; Han, Se Hwan; Jung, Yong Sik; Nam, Seok Jin

2017-11-01

Axillary lymph node (ALN) status is an important prognostic factor for breast cancer patients. With increasing numbers of patients undergoing neoadjuvant chemotherapy (NAC), issues concerning sentinel lymph node biopsy (SLNB) after NAC have emerged. We analyzed the clinicopathologic features and developed a nomogram to predict the possibility of nonsentinel lymph node (NSLN) metastases in patients with positive SLNs after NAC. A retrospective medical record review was performed of 140 patients who had had clinically positive ALNs at presentation, had a positive SLN after NAC on subsequent SLNB, and undergone axillary lymph node dissection (ALND) from 2008 to 2014. On multivariate stepwise logistic regression analysis, pathologic T stage, lymphovascular invasion, SLN metastasis size, and number of positive SLN metastases were independent predictors for NSLN metastases (P Samsung Medical Center NAC nomogram was developed to predict the likelihood of additional positive NSLNs. The Samsung Medical Center NAC nomogram could provide information to surgeons regarding whether to perform additional ALND when the permanent biopsy revealed positive findings, although the intraoperative SLNB findings were negative. Copyright © 2017 Elsevier Inc. All rights reserved.

The consequences of balanced harvesting of fish communities

DEFF Research Database (Denmark)

Jacobsen, Nis Sand; Gislason, Henrik; Andersen, Ken Haste

2014-01-01

community structure and yield. We use a size- and trait-based model that resolves individual interactions through competition and predation to compare balanced harvesting with traditional selective harvesting, which protects juvenile fish from fishing. Four different exploitation patterns, generated......Balanced harvesting, where species or individuals are exploited in accordance with their productivity, has been proposed as a way to minimize the effects of fishing on marine fish communities and ecosystems. This calls for a thorough examination of the consequences balanced harvesting has on fish...... by combining selective or unselective harvesting with balanced or unbalanced fishing, are compared. We find that unselective balanced fishing, where individuals are exploited in proportion to their productivity, produces a slightly larger total maximum sustainable yield than the other exploitation patterns and...

Harvesting Ambient Environmental Energy for Wireless Sensor Networks: A Survey

Directory of Open Access Journals (Sweden)

Gongbo Zhou

2014-01-01

Full Text Available In recent years, wireless sensor networks (WSNs have grown dramatically and made a great progress in many applications. But having limited life, batteries, as the power sources of wireless sensor nodes, have restricted the development and application of WSNs which often requires a very long lifespan for better performance. In order to make the WSNs prevalent in our lives, an alternative energy source is required. Environmental energy is an attractive power source, and it provides an approach to make the sensor nodes self-powered with the possibility of an almost infinite lifetime. The goal of this survey is to present a comprehensive review of the recent literature on the various possible energy harvesting technologies from ambient environment for WSNs.

Frequency adjustable MEMS vibration energy harvester

Science.gov (United States)

Podder, P.; Constantinou, P.; Amann, A.; Roy, S.

2016-10-01

Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators.

Frequency adjustable MEMS vibration energy harvester

International Nuclear Information System (INIS)

Podder, P; Constantinou, P; Roy, S; Amann, A

2016-01-01

Ambient mechanical vibrations offer an attractive solution for powering the wireless sensor nodes of the emerging “Internet-of-Things”. However, the wide-ranging variability of the ambient vibration frequencies pose a significant challenge to the efficient transduction of vibration into usable electrical energy. This work reports the development of a MEMS electromagnetic vibration energy harvester where the resonance frequency of the oscillator can be adjusted or tuned to adapt to the ambient vibrational frequency. Micro-fabricated silicon spring and double layer planar micro-coils along with sintered NdFeB micro-magnets are used to construct the electromagnetic transduction mechanism. Furthermore, another NdFeB magnet is adjustably assembled to induce variable magnetic interaction with the transducing magnet, leading to significant change in the spring stiffness and resonance frequency. Finite element analysis and numerical simulations exhibit substantial frequency tuning range (25% of natural resonance frequency) by appropriate adjustment of the repulsive magnetic interaction between the tuning and transducing magnet pair. This demonstrated method of frequency adjustment or tuning have potential applications in other MEMS vibration energy harvesters and micromechanical oscillators. (paper)

Precoding Design of MIMO Amplify-and-Forward Communication System With an Energy Harvesting Relay and Possibly Imperfect CSI

KAUST Repository

Benkhelifa, Fatma; Alouini, Mohamed-Slim

2017-01-01

In this paper, we investigate the simultaneous wireless information and power transfer (SWIPT) in a Multiple-Input Multiple-Output (MIMO) Amplify-and-Forward (AF) relay communication system where the relay is an energy harvesting (EH) node

A 3D Two-node and One-node HCMFD Algorithm for Pin-wise Reactor Analysis

International Nuclear Information System (INIS)

Kim, Jaeha; Kim, Yonghee

2016-01-01

To maximize the parallel computational efficiency, an iterative local-global strategy is adopted in the HCMFD algorithm. The global eigenvalue problem is solved by one-node CMFD, and the local fixed-source problems are solved by two-node CMFD based on the pin-wise nodal solutions. In such local-global scheme, the computational cost is mostly concentrated in solving the local problems while they can be solved in parallel so that a parallel computing can effectively be applied. Previously, the feasibility of the HCMFD algorithm was evaluated only in a 2-D scheme. In this paper, the 3D HCMFD algorithm with some possible variations in treating the axial direction is introduced. The HCMFD algorithm was successfully extended to a 3-D core analysis without any numerical instability even though the axial mesh size in local problems is quite different from the x-y node size. We have shown that 3D pin-wise core analysis can be done very effectively with the HCMFD framework. Additionally, it was demonstrated that parallel efficiency of the new 3D HCMFD scheme can be quite high on a simple OpenMP parallel architecture. It is concluded that the 3D HCMFD will enable an efficient pin-wise 3D core analysis

Improving the Power out of a Piezoelectric Energy Harvester Using Segmented Electrodes

Directory of Open Access Journals (Sweden)

SAJID RAFIQUE

2017-01-01

Full Text Available Vibration-based EH (Energy Harvesting using piezoelectric materials have been investigated by several research groups with the aim of harvesting maximum energy and providing power to low-powered wireless electronic systems for their entire operational life. The main areas of research includes improvements in mathematical modelling, optimization of harvester geometry, developments in electrical circuitry, advancements in charge storage devices and investigating various piezoelectric materials to achieve maximum power output. This paper investigates and compares the electrical power output with whole length electrodes and with segmentation of electrodes for the same harvester length. It is found that the voltage generated by one electrode of length l/2 of the direction-fixed tip system is significantly greater than that produced by one electrode of length l of the free tip system. This paper also verifies the fact that segmentation of electrodes reduces the effect of strain nodes and charge cancellation particularly at higher mode frequencies. The paper presents the simulation results using DSM (Dynamic Stiffness Matrix which is a compact method of modelling piezoelectric beams

Improving the power out of a piezoelectric energy harvester using segmented electrodes

International Nuclear Information System (INIS)

Rafiq, S.; Shah, S.A.

2017-01-01

Vibration-based EH (Energy Harvesting) using piezoelectric materials have been investigated by several research groups with the aim of harvesting maximum energy and providing power to low-powered wireless electronic systems for their entire operational life. The main areas of research includes improvements in mathematical modelling, optimization of harvester geometry, developments in electrical circuitry, advancements in charge storage devices and investigating various piezoelectric materials to achieve maximum power output. This paper investigates and compares the electrical power output with whole length electrodes and with segmentation of electrodes for the same harvester length. It is found that the voltage generated by one electrode of length l/2 of the direction-fixed tip system is significantly greater than that produced by one electrode of length l of the free tip system. This paper also verifies the fact that segmentation of electrodes reduces the effect of strain nodes and charge cancellation particularly at higher mode frequencies. The paper presents the simulation results using DSM (Dynamic Stiffness Matrix) which is a compact method of modelling piezoelectric beams. (author)

Radio frequency energy harvesting and low power data transmission for autonomous wireless sensor nodes

NARCIS (Netherlands)

Rodrigues Mansano, A.L.

2016-01-01

Since the Internet of Things (IoT) is expected to be the new technology to drive the semiconductor industry, significant research efforts have been made to develop new circuit and system techniques for autonomous/very low-power operation of wireless sensor nodes. Very low-power consumption of

Correlation between tumor size and surveillance of lymph node metastasis for IB and IIA cervical cancer by magnetic resonance images

International Nuclear Information System (INIS)

Kim, See Hyung; Lee, Hee Jung; Kim, Young Whan

2012-01-01

Purpose: To assess the feasibility of preoperative MRI based measurement of tumor size with regard to lymph node (LN) metastasis in early uterine cervical cancer. Material and Methods: A retrospective review of patients with FIGO stage IB–IIA cervical cancer who underwent lymphadenectomy was performed. Diagnostic accuracy of MRI in detecting LN metastasis and rate of LN recurrence in terms of tumor size (≤4 cm versus >4 cm) were analyzed. ROC curve analysis was used to determine LN size for differentiating LN metastasis in terms of tumor size. P 4 cm revealed higher diagnostic accuracy of MRI in detecting LN metastasis (85.4% versus 50.6%, P = 0.023) and rate of LN recurrence (20.0% versus 6.4%, P = 0.031) in than those with size with ≤4 cm, the differences were statistically significant. Discriminant analysis of LN size for the differentiation of metastasis from non-metastasis resulted in cut-off values (11.8 mm; size with >4 cm versus 8.3 mm; size with ≤4 cm) and diagnostic accuracy (84.0% of size with >4 cm versus 72.0% of size with ≤4 cm). Conclusion: MRI has limited sensitivity, but high specificity in predicting surveillance of LN metastasis in the preoperative early cervical cancer, especially useful tool for patients with tumor size with >4 cm.

Differential fat harvesting

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Sebastian Torres Farr

2014-12-01

Full Text Available Aim: Volume replacement with fillers is regularly performed with the use of diverse volumetric materials to correct different structures around the face, depending on the volume enhancement required and the thickness of the soft tissue envelope. Differential fat harvesting and posterior grafting is performed to place the correct fat parcel size for each target area, expanding the potential applications of fat. Methods: Sixty patients consecutively recruited on a first come basis undergone a facial fat grafting procedure, in private practice setting between March 2012 and October 2013. Fat grafting quantity and quality was predicted for each case. Differential harvesting was performed, with 2 fat parcels size. Processing was performed through washing. Fat infiltration was carried out through small cannulas or needles depending on the treated area. Outcomes were analysed both by the physicians and the patients at 7 days, 1 month, 3 months and 6 months through a perceived satisfaction questionnaire. Parameters considered were downtime or discomfort, skin benefits, volume restoration, reabsorption rate estimated and overall improvement. Results: Full facial differential fat grafting procedure lasted an average of 1.5-2.5 h. Average downtime was 3-4 days. Follow-up was performed to a minimum of 6 months. Both patient and physician overall satisfaction rates were mostly excellent. Adverse events like lumps or irregularities were not encountered. Conclusion: Differential fat harvesting and posterior grafting is a valid alternative, to expand the repertoire of fat use, allow a more homogeneous effect, reduce the potential complications, speed up the process, improve graft survival, and to enhance overall aesthetic outcome.

EANM practice guidelines for lymphoscintigraphy and sentinel lymph node biopsy in melanoma

Energy Technology Data Exchange (ETDEWEB)

Bluemel, Christina; Herrmann, Ken; Lassmann, Michael [Universitaetsklinikum Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Giammarile, Francesco; Dubreuil, Julien [Universite Claude Bernard Lyon 1, Medecine Nucleaire, Hospices Civils de Lyon and EA 3738, Lyon (France); Nieweg, Omgo E.; Chakera, Annette H. [The Poche Centre, Melanoma Institute Australia, North Sydney (Australia); Testori, Alessandro [European Institute of Oncology, Milan (Italy); Audisio, Riccardo A. [University of Liverpool, St Helens Teaching Hospital, St Helens (United Kingdom); Zoras, Odysseas [University Hospital of Heraklion, Department of Surgical Oncology, Heraklion (Greece); Uren, Roger [The University of Sydney, Sydney Medical School, Sydney, NSW (Australia); Alfred Nuclear Medicine and Ultrasound, RPAH Medical Centre, Newtown, NSW (Australia); Chondrogiannis, Sotirios; Rubello, Domenico [' Santa Maria della Misericordia' Hospital, Department of Nuclear Medicine, PET/CT Centre, Radiology, NeuroRadiology, Medical Physics, Rovigo (Italy); Colletti, Patrick M. [University of Southern California, Department of Radiology, Los Angeles, CA (United States)

2015-10-15

Sentinel lymph node biopsy is an essential staging tool in patients with clinically localized melanoma. The harvesting of a sentinel lymph node entails a sequence of procedures with participation of specialists in nuclear medicine, radiology, surgery and pathology. The aim of this document is to provide guidelines for nuclear medicine physicians performing lymphoscintigraphy for sentinel lymph node detection in patients with melanoma. These practice guidelines were written and have been approved by the European Association of Nuclear Medicine (EANM) to promote high-quality lymphoscintigraphy. The final result has been discussed by distinguished experts from the EANM Oncology Committee, national nuclear medicine societies, the European Society of Surgical Oncology (ESSO) and the European Association for Research and Treatment of Cancer (EORTC) melanoma group. The document has been endorsed by the Society of Nuclear Medicine and Molecular Imaging (SNMMI). The present practice guidelines will help nuclear medicine practitioners play their essential role in providing high-quality lymphatic mapping for the care of melanoma patients. (orig.)

Contrast-Enhanced MR Imaging of Lymph Nodes in Cancer Patients

International Nuclear Information System (INIS)

Choi, Seung Hong; Moon, Woo Kyung

2010-01-01

The accurate identification and characterization of lymph nodes by modern imaging modalities has important therapeutic and prognostic significance for patients with newly diagnosed cancers. The presence of nodal metastases limits the therapeutic options, and it generally indicates a worse prognosis for the patients with nodal metastases. Yet anatomic imaging (CT and MR imaging) is of limited value for depicting small metastatic deposits in normal-sized nodes, and nodal size is a poor criterion when there is no extracapsular extension or focal nodal necrosis to rely on for diagnosing nodal metastases. Thus, there is a need for functional methods that can be reliably used to identify small metastases. Contrast-enhanced MR imaging of lymph nodes is a non-invasive method for the analysis of the lymphatic system after the interstitial or intravenous administration of contrast media. Moreover, some lymphotrophic contrast media have been developed and used for detecting lymph node metastases, and this detection is independent of the nodal size. This article will review the basic principles, the imaging protocols, the interpretation and the accuracies of contrast-enhanced MR imaging of lymph nodes in patients with malignancies, and we also focus on the recent issues cited in the literature. In addition, we discuss the results of several pre-clinical studies and animal studies that were conducted in our institution

A Long-Distance RF-Powered Sensor Node with Adaptive Power Management for IoT Applications.

Science.gov (United States)

Pizzotti, Matteo; Perilli, Luca; Del Prete, Massimo; Fabbri, Davide; Canegallo, Roberto; Dini, Michele; Masotti, Diego; Costanzo, Alessandra; Franchi Scarselli, Eleonora; Romani, Aldo

2017-07-28

We present a self-sustained battery-less multi-sensor platform with RF harvesting capability down to -17 dBm and implementing a standard DASH7 wireless communication interface. The node operates at distances up to 17 m from a 2 W UHF carrier. RF power transfer allows operation when common energy scavenging sources (e.g., sun, heat, etc.) are not available, while the DASH7 communication protocol makes it fully compatible with a standard IoT infrastructure. An optimized energy-harvesting module has been designed, including a rectifying antenna (rectenna) and an integrated nano-power DC/DC converter performing maximum-power-point-tracking (MPPT). A nonlinear/electromagnetic co-design procedure is adopted to design the rectenna, which is optimized to operate at ultra-low power levels. An ultra-low power microcontroller controls on-board sensors and wireless protocol, to adapt the power consumption to the available detected power by changing wake-up policies. As a result, adaptive behavior can be observed in the designed platform, to the extent that the transmission data rate is dynamically determined by RF power. Among the novel features of the system, we highlight the use of nano-power energy harvesting, the implementation of specific hardware/software wake-up policies, optimized algorithms for best sampling rate implementation, and adaptive behavior by the node based on the power received.

A Long-Distance RF-Powered Sensor Node with Adaptive Power Management for IoT Applications

Directory of Open Access Journals (Sweden)

Matteo Pizzotti

2017-07-01

Full Text Available We present a self-sustained battery-less multi-sensor platform with RF harvesting capability down to −17 dBm and implementing a standard DASH7 wireless communication interface. The node operates at distances up to 17 m from a 2 W UHF carrier. RF power transfer allows operation when common energy scavenging sources (e.g., sun, heat, etc. are not available, while the DASH7 communication protocol makes it fully compatible with a standard IoT infrastructure. An optimized energy-harvesting module has been designed, including a rectifying antenna (rectenna and an integrated nano-power DC/DC converter performing maximum-power-point-tracking (MPPT. A nonlinear/electromagnetic co-design procedure is adopted to design the rectenna, which is optimized to operate at ultra-low power levels. An ultra-low power microcontroller controls on-board sensors and wireless protocol, to adapt the power consumption to the available detected power by changing wake-up policies. As a result, adaptive behavior can be observed in the designed platform, to the extent that the transmission data rate is dynamically determined by RF power. Among the novel features of the system, we highlight the use of nano-power energy harvesting, the implementation of specific hardware/software wake-up policies, optimized algorithms for best sampling rate implementation, and adaptive behavior by the node based on the power received.

Vertebral morphology influences the development of Schmorl's nodes in the lower thoracic vertebrae.

Science.gov (United States)

Plomp, Kimberly A; Roberts, Charlotte A; Viðarsdóttir, Una Strand

2012-12-01

Schmorl's nodes are the result of herniations of the nucleus pulposus into the adjacent vertebral body and are commonly identified in both clinical and archaeological contexts. The current study aims to identify aspects of vertebral shape that correlate with Schmorl's nodes. Two-dimensional statistical shape analysis was performed on digital images of the lower thoracic spine (T10-T12) of adult skeletons from the late medieval skeletal assemblages from Fishergate House, York, St. Mary Graces and East Smithfield Black Death cemeteries, London, and postmedieval Chelsea Old Church, London. Schmorl's nodes were scored on the basis of their location, depth, and size. Results indicate that there is a correlation between the shape of the posterior margin of the vertebral body and pedicles and the presence of Schmorl's nodes in the lower thoracic spine. The size of the vertebral body in males was also found to correlate with the lesions. Vertebral shape differences associated with the macroscopic characteristics of Schmorl's nodes, indicating severity of the lesion, were also analyzed. The shape of the pedicles and the posterior margin of the vertebral body, along with a larger vertebral body size in males, have a strong association with both the presence and severity of Schmorl's nodes. This suggests that shape and/or size of these vertebral components are predisposing to, or resulting in, vertically directed disc herniation. Copyright © 2012 Wiley Periodicals, Inc.

Effect of stage of maturity of grass at harvest on intake, chewing activity and distribution of particle size in faeces from pregnant ewes

DEFF Research Database (Denmark)

Jalali, Alireza; Nørgaard, Peder; Weisbjerg, Martin Riis

2012-01-01

This study was conducted to investigate the effect of stage of maturity at harvest on the intake of grass silage, eating and ruminating activity and the distribution of faecal particle size in ewes during late pregnancy. A total of 18 Swedish Finull × Dorset 85 ± 8 kg (mean ± s.d.) ewes bearing t...

Jungle Giants: Assessing Sustainable Harvesting in a Difficult-to-Survey Species (Python reticulatus.

Directory of Open Access Journals (Sweden)

Daniel J D Natusch

Full Text Available Sustainability of wildlife harvests is critical but difficult to assess. Evaluations of sustainability typically combine modelling with the measurement of underlying abundances. For many taxa harvested in developing countries, however, abundances are near-impossible to survey and a lack of detailed ecological information impedes the reliability of models. In such cases, repeated surveys of the attributes of harvested individuals may provide more robust information on sustainability. If the numbers, sizes and other demographic attributes of animals taken for the commercial trade do not change over biologically significant time intervals (decades, there is a prima facie case that the harvest is indeed sustainable. Here, we report the results of examinations of > 4,200 reticulated pythons (Python reticulatus taken for the commercial leather industry in northern and southern Sumatra, Indonesia. The numbers, mean body sizes, clutch sizes, sizes at maturity and proportion of giant specimens have not decreased between our first surveys (1995 and repeat surveys (2015. Thus, despite assumptions to the contrary, the harvest appears to be sustainable. We use our data to inform the design of future monitoring programs for this species. Our study underpins the need for robust science to inform wildlife trade policy and decision-making, and urges wildlife managers to assess sustainability of difficult-to-survey terrestrial wildlife by drawing inferences directly from the harvest itself.

Jungle Giants: Assessing Sustainable Harvesting in a Difficult-to-Survey Species (Python reticulatus).

Science.gov (United States)

Natusch, Daniel J D; Lyons, Jessica A; Mumpuni; Riyanto, Awal; Shine, Richard

2016-01-01

Sustainability of wildlife harvests is critical but difficult to assess. Evaluations of sustainability typically combine modelling with the measurement of underlying abundances. For many taxa harvested in developing countries, however, abundances are near-impossible to survey and a lack of detailed ecological information impedes the reliability of models. In such cases, repeated surveys of the attributes of harvested individuals may provide more robust information on sustainability. If the numbers, sizes and other demographic attributes of animals taken for the commercial trade do not change over biologically significant time intervals (decades), there is a prima facie case that the harvest is indeed sustainable. Here, we report the results of examinations of > 4,200 reticulated pythons (Python reticulatus) taken for the commercial leather industry in northern and southern Sumatra, Indonesia. The numbers, mean body sizes, clutch sizes, sizes at maturity and proportion of giant specimens have not decreased between our first surveys (1995) and repeat surveys (2015). Thus, despite assumptions to the contrary, the harvest appears to be sustainable. We use our data to inform the design of future monitoring programs for this species. Our study underpins the need for robust science to inform wildlife trade policy and decision-making, and urges wildlife managers to assess sustainability of difficult-to-survey terrestrial wildlife by drawing inferences directly from the harvest itself.

Numerical study and design optimization of electromagnetic energy harvesters integrated with flexible magnetic materials

Energy Technology Data Exchange (ETDEWEB)

Yoon, Sang Won [Hanyang University, Seoul (Korea, Republic of)

2017-05-15

This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.

Numerical study and design optimization of electromagnetic energy harvesters integrated with flexible magnetic materials

International Nuclear Information System (INIS)

Yoon, Sang Won

2017-01-01

This study presents a new design of an electromagnetic energy harvester integrated with a soft magnetic material. The harvester design optimizes the magnetic material characteristics and the size of a rectangular permanent magnet. The design employs a complete magnetic circuit made of (1) a thin-film soft magnetic material that facilitates a flexible but highly (magnetically) permeable beam and (2) an optimally-sized magnet that maximizes the harvester performance. The design is demonstrated to reduce magnetic flux leakage, and thus considerably enhances both magnetic flux density (B) and its change by time (dB/dt), which both influence harvester performance. The improvement in harvester performances strongly depends on critical design parameters, especially, the magnet size and characteristics of magnetic materials, including permeability, stiffness, and thickness. The analyses conclude that recently-introduced nanomaterials (having ultrahigh magnetic permeability) can potentially innovate harvester performances. However, the performance may be degraded without design optimization. Once optimized, the integrated nanomaterials facilitate a significant improvement compared with a conventional design without integrated magnetic materials.

One node driving synchronisation

Science.gov (United States)

Wang, Chengwei; Grebogi, Celso; Baptista, Murilo S.

2015-12-01

Abrupt changes of behaviour in complex networks can be triggered by a single node. This work describes the dynamical fundamentals of how the behaviour of one node affects the whole network formed by coupled phase-oscillators with heterogeneous coupling strengths. The synchronisation of phase-oscillators is independent of the distribution of the natural frequencies, weakly depends on the network size, but highly depends on only one key oscillator whose ratio between its natural frequency in a rotating frame and its coupling strength is maximum. This result is based on a novel method to calculate the critical coupling strength with which the phase-oscillators emerge into frequency synchronisation. In addition, we put forward an analytical method to approximately calculate the phase-angles for the synchronous oscillators.

Growth and fillet quality attributes of five genetic strains of rainbow trout (Oncorhynchus mykiss) reared in a partial water reuse system and harvested at different sizes

Science.gov (United States)

Genetics and environment can interact to influence fish growth performance and product quality attributes. Interaction in recirculating aquaculture systems (RAS) makes selection of fish strain and harvest sizes critical for optimizing fish quality. Definition of growth performance and quality outcom...

A Multi-Hop Energy Neutral Clustering Algorithm for Maximizing Network Information Gathering in Energy Harvesting Wireless Sensor Networks.

Science.gov (United States)

Yang, Liu; Lu, Yinzhi; Zhong, Yuanchang; Wu, Xuegang; Yang, Simon X

2015-12-26

Energy resource limitation is a severe problem in traditional wireless sensor networks (WSNs) because it restricts the lifetime of network. Recently, the emergence of energy harvesting techniques has brought with them the expectation to overcome this problem. In particular, it is possible for a sensor node with energy harvesting abilities to work perpetually in an Energy Neutral state. In this paper, a Multi-hop Energy Neutral Clustering (MENC) algorithm is proposed to construct the optimal multi-hop clustering architecture in energy harvesting WSNs, with the goal of achieving perpetual network operation. All cluster heads (CHs) in the network act as routers to transmit data to base station (BS) cooperatively by a multi-hop communication method. In addition, by analyzing the energy consumption of intra- and inter-cluster data transmission, we give the energy neutrality constraints. Under these constraints, every sensor node can work in an energy neutral state, which in turn provides perpetual network operation. Furthermore, the minimum network data transmission cycle is mathematically derived using convex optimization techniques while the network information gathering is maximal. Simulation results show that our protocol can achieve perpetual network operation, so that the consistent data delivery is guaranteed. In addition, substantial improvements on the performance of network throughput are also achieved as compared to the famous traditional clustering protocol LEACH and recent energy harvesting aware clustering protocols.

A Multi-Hop Energy Neutral Clustering Algorithm for Maximizing Network Information Gathering in Energy Harvesting Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Liu Yang

2015-12-01

Full Text Available Energy resource limitation is a severe problem in traditional wireless sensor networks (WSNs because it restricts the lifetime of network. Recently, the emergence of energy harvesting techniques has brought with them the expectation to overcome this problem. In particular, it is possible for a sensor node with energy harvesting abilities to work perpetually in an Energy Neutral state. In this paper, a Multi-hop Energy Neutral Clustering (MENC algorithm is proposed to construct the optimal multi-hop clustering architecture in energy harvesting WSNs, with the goal of achieving perpetual network operation. All cluster heads (CHs in the network act as routers to transmit data to base station (BS cooperatively by a multi-hop communication method. In addition, by analyzing the energy consumption of intra- and inter-cluster data transmission, we give the energy neutrality constraints. Under these constraints, every sensor node can work in an energy neutral state, which in turn provides perpetual network operation. Furthermore, the minimum network data transmission cycle is mathematically derived using convex optimization techniques while the network information gathering is maximal. Simulation results show that our protocol can achieve perpetual network operation, so that the consistent data delivery is guaranteed. In addition, substantial improvements on the performance of network throughput are also achieved as compared to the famous traditional clustering protocol LEACH and recent energy harvesting aware clustering protocols.

Nomogram for prediction of level 2 axillary lymph node metastasis in proven level 1 node-positive breast cancer patients.

Science.gov (United States)

Jiang, Yanlin; Xu, Hong; Zhang, Hao; Ou, Xunyan; Xu, Zhen; Ai, Liping; Sun, Lisha; Liu, Caigang

2017-09-22

The current management of the axilla in level 1 node-positive breast cancer patients is axillary lymph node dissection regardless of the status of the level 2 axillary lymph nodes. The goal of this study was to develop a nomogram predicting the probability of level 2 axillary lymph node metastasis (L-2-ALNM) in patients with level 1 axillary node-positive breast cancer. We reviewed the records of 974 patients with pathology-confirmed level 1 node-positive breast cancer between 2010 and 2014 at the Liaoning Cancer Hospital and Institute. The patients were randomized 1:1 and divided into a modeling group and a validation group. Clinical and pathological features of the patients were assessed with uni- and multivariate logistic regression. A nomogram based on independent predictors for the L-2-ALNM identified by multivariate logistic regression was constructed. Independent predictors of L-2-ALNM by the multivariate logistic regression analysis included tumor size, Ki-67 status, histological grade, and number of positive level 1 axillary lymph nodes. The areas under the receiver operating characteristic curve of the modeling set and the validation set were 0.828 and 0.816, respectively. The false-negative rates of the L-2-ALNM nomogram were 1.82% and 7.41% for the predicted probability cut-off points of level 1 axillary lymph node metastasis. Patients with a low probability of L-2-ALNM could be spared level 2 axillary lymph node dissection, thereby reducing postoperative morbidity.

Prognostic relevance of lymph node ratio and total lymph node count for small bowel adenocarcinoma.

Science.gov (United States)

Tran, Thuy B; Qadan, Motaz; Dua, Monica M; Norton, Jeffrey A; Poultsides, George A; Visser, Brendan C

2015-08-01

Nodal metastasis is a known prognostic factor for small bowel adenocarcinoma. The goals of this study were to evaluate the number of lymph nodes (LNs) that should be retrieved and the impact of lymph node ratio (LNR) on survival. Surveillance, Epidemiology, and End Results was queried to identify patients with small bowel adenocarcinoma who underwent resection from 1988 to 2010. Survival was calculated with the Kaplan-Meier method. Multivariate analysis identified predictors of survival. A total of 2,772 patients underwent resection with at least one node retrieved, and this sample included equal numbers of duodenal (n = 1,387) and jejunoileal (n = 1,386) adenocarcinomas. There were 1,371 patients with no nodal metastasis (N0, 49.4%), 928 N1 (33.5%), and 474 N2 (17.1%). The median numbers of LNs examined for duodenal and jejunoileal cancers were 9 and 8, respectively. Cut-point analysis demonstrated that harvesting at least 9 for jejunoileal and 5 LN for duodenal cancers resulted in the greatest survival difference. Increasing LNR at both sites was associated with decreased overall median survival (LNR = 0, 71 months; LNR 0-0.02, 35 months; LNR 0.21-0.4, 25 months; and LNR >0.4, 16 months; P < .001). Multivariate analysis confirmed number of LNs examined, T-stage, LN positivity, and LNR were independent predictors of survival. LNR has a profound impact on survival in patients with small bowel adenocarcinoma. To achieve adequate staging, we recommend retrieving a minimum of 5 LN for duodenal and 9 LN for jejunoileal adenocarcinomas. Copyright © 2015 Elsevier Inc. All rights reserved.

MECHANIZED HARVESTING TESTS PERFORMED BY GRAPE HARVESTERS IN SUPER INTENSIVE OLIVE ORCHARD CULTIVATION IN SPAIN

Directory of Open Access Journals (Sweden)

Gennaro Giametta

2009-06-01

Full Text Available Today also those countries boasting a century-old olive growing tradition have to look at the latest, most dynamic, non labour-intensive olive growing systems to abate production (notably, harvesting operations costs and remain competitive in a globalized market. This is why over the last few years super intensive olive orchard cultivation has been attracting a lot of interest on the part of olive growers all over the world as it accounts for an innovative model whereby olive groves are tailored to the special needs of grape harvesters. This paper reports the first results of experimental mechanical harvesting tests in a super-intensive olive cultivation. The study is intended to explore both productivity and work capacity of two of the most commonly used grape harvesters, Grégoire G120SW and New Holland Braud VX680, in a view to assessing their harvesting performance by a series of tests conducted in Spain. On the basis of the tests it was possible to verify that the machines are able to detach the almost all the drupes (more than 90%, with one only passage, and this independently of both size and location of drupes on the tree crown and of their maturity stage. Using these machines, two people can often carry out the whole harvest process: an operator driving the harvester and another person transferring the fruit from the harvester in the field to the olive oil mill for processing. With this system, the work speed is usually, in the best working conditions, about 1.7 km/hour and the average harvesting time is about 2.5-3 hours/ha. For the time being it is however impossible to draw definitive conclusions in terms of performance of the above cultivation systems and harvesting machines. Additional key observational studies are needed in the years to come to assess the efficiency of the entire model.

Comparison of four staging systems of lymph node metastasis in gastric cancer.

Science.gov (United States)

Zhang, Ming; Zhu, Guanyu; Ma, Yan; Xue, Yingwei

2009-11-01

The classification of lymph node metastasis in patients with gastric cancer is still controversial. Our aim was to evaluate the relative merits of four staging systems of lymph node metastasis. In our study, the nodal status was classified according to the 5th edition of the tumor node metastasis (TNM) system, the Japanese Classification of Gastric Carcinoma (JCGC), the ratio of metastatic lymph nodes, and the size of the largest metastatic lymph node. Each staging system was scored as good (+2), fair (+1), or poor (0) with respect to the theoretical value (extent of the anatomical lymphatic tumor spread), convenience (simplicity), surgical applicability (extent of lymph node dissection), and prognostic value (ability to predict survival rate). In the multivariate analysis including the four staging systems and other potential prognostic factors, stepwise Cox regression revealed that the ratio of metastatic lymph nodes was the most independent prognostic factor. The TNM, ratio, and size systems were convenient because they had no consideration for the location of the tumor and lymph node. Although the JCGC system had advantages in theoretical value and surgical application, it was most optional due to the complexity of the system. Although all different staging systems are comparable, the metastatic lymph node ratio system is convenient, reproducible, and has the highest ability to predict survival.

Dust emissions eliminated in pneumatic harvesting

International Nuclear Information System (INIS)

Kallio, M.

1998-01-01

Pneumatic harvesting is the most efficient milled peat production method in unsteady weather conditions. In good summers, the best contractors harvest more than 1 000 m 3 /ha milled peat from suitable production fields. The greatest problem of the method is caused by dust emissions, in particular in fields close to settled areas. About 15 % of Finland's present peat production is collected using pneumatic harvesters. A pneumatic harvester with smaller dust emissions has been developed by VTT Energy and Vapo Oy. The wagon is based on two-stage separation of peat. The main part of the coarser milled peat is first separated, e.g. in a settling chamber, and fine dry peat dust in correctly dimensioned side by side cyclones. The first series of pneumatic harvesters based on the new separation technology was employed in summer 1996. Besides decreasing the dust emissions the harvesting capacity of the new equipment was increased. The collection capacity of the pneumatic harvester can be made more effective by enlarging the container size, be decreasing the weight, by increasing the driving speed and by developing the suction capacity. Using lighter and durable construction materials combined with advanced design lighter and stronger pneumatic harvesters have been constructed. Nozzles and their mounting have also been developed. In the improvement of nozzles, the former studies with pneumatic simulator of VTT Energy, have been of great help. Studies with the pneumatic simulator and field conditions have been made in collaboration with Turveruukki Oy, Turvemetalli Oy, Raussin Metalli Oy and Vapo Oy, as well as VNIITP of St. Petersburg, Russia

The reduced local lymph node assay: the impact of group size.

Science.gov (United States)

Ryan, Cindy A; Chaney, Joel G; Kern, Petra S; Patlewicz, Grace Y; Basketter, David A; Betts, Catherine J; Dearman, Rebecca J; Kimber, Ian; Gerberick, G Frank

2008-05-01

The local lymph node assay (LLNA) is a skin sensitization test that provides animal welfare benefits. To reduce animal usage further, a modified version (rLLNA) was proposed. Conducting the rLLNA as a screening test with a single high dose group and vehicle control differentiated accurately between skin sensitizers and non-sensitizers. This study examined whether a reduction in animal number/group is feasible. Historical data were utilized to examine the impact of conducting the rLLNA with two mice/group. To assess the effect on the stimulation index (SI) 41 datasets with individual animal data derived using five mice/group were analysed. SIs were calculated on all possible combinations of two control and two high dose group disintegrations per minute (dpm) values. For 25 of 33 sensitizer datasets, > 96% of possible dpm combinations resulted in a calculated SI > 3. The lowest percentages of positive SIs were observed with weak allergens when, in the standard LLNA, the mean SIs would have been nearer to the threshold value of 3. The results indicate that moderate, strong and extreme allergens are more likely than weak allergens to be identified as sensitizers when group sizes of two mice are used within the rLLNA. It is concluded that a rLLNA with two mice/group would display decreased sensitivity and is inappropriate for use in hazard identification. Copyright (c) 2007 John Wiley & Sons, Ltd.

Allometric analysis of the effects of density on reproductive allocation and Harvest Index in 6 varieties of wheat (Triticum)

DEFF Research Database (Denmark)

Qin, Xiao-liang; Weiner, Jacob; Qi, Lin

2013-01-01

allocation should be analyzed and interpreted allometrically because ratios or fractions such as Reproductive Effort or Harvest Index are size dependent. We investigated reproductive allocation of individuals in 6 varieties of Triticum (wheat) grown at a wide range of densities. We harvested leaves, stems...... size. There were significant differences among the varieties in the allometric exponent (slope of log–log relationship) of grain versus vegetative mass, such that some varieties produced higher yield (and therefore had a higher Harvest Index) than others when plants were small, while others had higher...... yield at larger sizes. Thus, the Harvest Index and its rank among varieties changed with plant size, which puts into question the practice of selecting for Harvest Index when crop performance varies greatly among individuals, years or environments. Selection for a high Harvest Index when individuals...

Integration of Small-Diameter Wood Harvesting in Early Thinnings using the Two pile Cutting Method

Energy Technology Data Exchange (ETDEWEB)

Kaerhae, Kalle (Metsaeteho Oy, P.O. Box 101, FI-00171 Helsinki (Finland))

2008-10-15

Metsaeteho Oy studied the integrated harvesting of industrial roundwood (pulpwood) and energy wood based on a two-pile cutting method, i.e. pulpwood and energy wood fractions are stacked into two separate piles when cutting a first-thinning stand. The productivity and cost levels of the integrated, two-pile cutting method were determined, and the harvesting costs of the two-pile method were compared with those of conventional separate wood harvesting methods. In the time study, when the size of removal was 50 dm3, the productivity in conventional whole-tree cutting was 6% higher than in integrated cutting. With a stem size of 100 dm3, the productivity in whole-tree cutting was 7% higher than in integrated cutting. The results indicated, however, that integrated harvesting based on the two-pile method enables harvesting costs to be decreased to below the current cost level of separate pulpwood harvesting in first thinning stands. The greatest cost-saving potential lies in small-sized first thinnings. The results showed that, when integrated wood harvesting based on the two-pile method is applied, the removals of both energy wood and pulpwood should be more than 15-20 m3/ha at the harvesting sites in order to achieve economically viable integrated procurement

Factors affecting unintentional harvesting selectivity in a monomorphic species.

Science.gov (United States)

Bunnefeld, Nils; Baines, David; Newborn, David; Milner-Gulland, E J

2009-03-01

1. Changes in the abundance of populations have always perplexed ecologists but long-term studies are revealing new insights into population dynamic processes. Long-term data are often derived from harvest records although many wild populations face high harvesting pressures leading to overharvesting and extinction. Additionally, harvest records used to describe population processes such as fluctuations in abundance and reproductive success often assume a random off-take. 2. Selective harvesting based on phenotypic characteristics occurs in many species (e.g. trophy hunting, fisheries) and has important implications for population dynamics, conservation and management. 3. In species with no marked morphological differences between the age and sex classes, such as the red grouse Lagopus lagopus scoticus during the shooting season, hunters cannot consciously select for a specific sex or age class during the shooting process but harvest records could still give a biased reflection of the population structure because of differences in behaviour between age and sex classes. 4. This study compared age and sex ratios in the bag with those in the population before shooting for red grouse at different points in the shooting season and different densities, which has rarely been tested before. 5. More young than old grouse were shot at large bag sizes and vice versa for small bag sizes than would be expected from the population composition before shooting. The susceptibility of old males to shooting compared to females increased with bag size and was high at the first time the area was shot but decreased with the number of times an area was harvested. 6. These findings stress that the assumption made in many studies that harvest records reflect the age and sex ratio of the population and therefore reflect productivity can be misleading. 7. In this paper, as in the literature, it is also shown that number of grouse shot reflects grouse density and therefore that hunting

Prognostic factors in patients with node-negative gastric cancer: an Indian experience

Directory of Open Access Journals (Sweden)

Ranganathan Rama

2011-05-01

Full Text Available Abstract Background The status of the regional nodes is the most important prognostic factor in gastric cancer. There are subgroups of patients with different prognosis even in node-negative patients of gastric cancer. The aim of this study is to analyze the factors influencing the prognosis in Indian patients with node-negative gastric cancer. Methods This was a retrospective analysis of patients who underwent radical gastrectomy in a tertiary cancer centre in India between1991 and 2007. The study group included only patients with histologically node-negative disease. Various clinical, pathological and treatment related factors in this group of patients were analyzed to determine their prognostic ability by univariate and multivariate analyses. Results Among the 417 patients who underwent gastrectomy during this period, 122 patients had node-negative disease. A major proportion of the patients had advanced gastric cancer. The 5-year overall survival and disease-free survival in all node-negative gastric cancer patients was 68.2% and 67.5% respectively. The overall recurrence rate in this group was 27.3%. On univariate analysis, the factors found to significantly influence the disease-free survival were the size, location and presence or absence of serosal invasion of the primary tumor. However, on multivariate analysis, only tumor size more than 3 cm and serosal invasion were found to be independently associated with an inferior survival. Conclusion Serosal invasion and primary tumor size more than 3 cm independently predict a poor outcome in patients with node-negative gastric cancer.

Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications.

Science.gov (United States)

Khan, Farid Ullah

For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters' wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented.

Cervical lymph node metastasis of oral squamous cell carcinomas. CT enhancement and histopathological evaluations

Energy Technology Data Exchange (ETDEWEB)

Etoh, Yohei; Kimura, Takuji; Sasaki, Akira; Kishimoto, Koji; Matsumura, Tomohiro; Kishi, Kanji [Okayama Univ. (Japan). Dental School

2000-06-01

A comparison of the results of histopathological and enhanced CT examinations were carried out for 88 patients with oral squamous cell carcinomas who underwent neck dissection. CT scanning (5-mm thick section) images obtained during bolus/drip injection of Iopamidol were routinely taken through the neck. Ninety-two of 1634 nodes were histologically diagnosed as metastatic. Low density areas surrounding enhancement rims were metastatic nodal central necrosis or keratinization. Enhanced areas in many metastatic nodes were considered to be lymphatic architecture, not metastatic masses especially in the avascular keratinization. Enhanced CT produced accurate information of lymph node size, location, shape, grouping and spread from nodes to adjacent structures. However, it was considered that not every metastatic lymph node should show enlargement and/or enhancement. Improved assessment of solid metastatic features of lymph nodes (shape, size, and involvement) may be achieved with the aid of thin-thickness CT. (author)

Cervical lymph node metastasis of oral squamous cell carcinomas. CT enhancement and histopathological evaluations

International Nuclear Information System (INIS)

Etoh, Yohei; Kimura, Takuji; Sasaki, Akira; Kishimoto, Koji; Matsumura, Tomohiro; Kishi, Kanji

2000-01-01

A comparison of the results of histopathological and enhanced CT examinations were carried out for 88 patients with oral squamous cell carcinomas who underwent neck dissection. CT scanning (5-mm thick section) images obtained during bolus/drip injection of Iopamidol were routinely taken through the neck. Ninety-two of 1634 nodes were histologically diagnosed as metastatic. Low density areas surrounding enhancement rims were metastatic nodal central necrosis or keratinization. Enhanced areas in many metastatic nodes were considered to be lymphatic architecture, not metastatic masses especially in the avascular keratinization. Enhanced CT produced accurate information of lymph node size, location, shape, grouping and spread from nodes to adjacent structures. However, it was considered that not every metastatic lymph node should show enlargement and/or enhancement. Improved assessment of solid metastatic features of lymph nodes (shape, size, and involvement) may be achieved with the aid of thin-thickness CT. (author)

Design, fabrication, and testing of a low frequency MEMS piezoelectromagnetic energy harvester

Science.gov (United States)

Fernandes, Egon; Martin, Blake; Rua, Isabel; Zarabi, Sid; Debéda, Hélène; Nairn, David; Wei, Lan; Salehian, Armaghan

2018-03-01

This paper details a power solution for smart grid applications to replace batteries by harvesting the electromagnetic energy from a current-carrying wire. A MEMS piezoelectromagnetic energy harvester has been fabricated using PZT screen-printing technology with a centrally-supported meandering geometry. The energy harvesting device employs a symmetric geometry to increase its power output by reducing the effects of the torsional modes and the resultant overall strain nodes in the system subsequently reduce the complexities for the electrode fabrication. The unit is modelled using COMSOL to determine mode shapes and frequency response functions. A 12.7 mm by 14.7 mm unit is fabricated by screen-printing 75 μm-thick PZT on a stainless steel substrate and then experimentally tested to validate the FEA results. Experimentally, the harvester is shown to produce 9 μW from a wire carrying 7 A while operating at a distance of 6.5 mm from the wire. The design of the current work results in a greater normalized power density than other MEMS based piezoelectromagnetic devices and shows great potential relative to larger devices that use bulk or thin film piezoelectrics.

Development of an adaptive harvest management program for Taiga bean geese

Science.gov (United States)

Johnson, Fred A.; Alhainen, Mikko; Fox, Anthony D.; Madsen, Jesper

2016-01-01

This report describes recent progress in specifying the elements of an adaptive harvest program for taiga bean goose. It describes harvest levels appropriate for first rebuilding the population of the Central Management Unit and then maintaining it near the goal specified in the AEWA International Single Species Action Plan (ISSAP). This report also provides estimates of the length of time it would take under ideal conditions (no density dependence and no harvest) to rebuild depleted populations in the Western and Eastern Management Units. We emphasize that our estimates are a first approximation because detailed demographic information is lacking for taiga bean geese. Using allometric relationships, we estimated parameters of a thetalogistic matrix population model. The mean intrinsic rate of growth was estimated as r = 0.150 (90% credible interval: 0.120 – 0.182). We estimated the mean form of density dependence as   2.361 (90% credible interval: 0.473 – 11.778), suggesting the strongest density dependence occurs when the population is near its carrying capacity. Based on expert opinion, carrying capacity (i.e., population size expected in the absence of hunting) for the Central Management Unit was estimated as K  87,900 (90% credible interval: 82,000 – 94,100). The ISSAP specifies a population goal for the Central Management Unit of 60,000 – 80,000 individuals in winter; thus, we specified a preliminary objective function as one which would minimize the difference between this goal and population size. Using the concept of stochastic dominance to explicitly account for uncertainty in demography, we determined that optimal harvest rates for 5, 10, 15, and 20-year time horizons were h = 0.00, 0.02, 0.05, and 0.06, respectively. These optima represent a tradeoff between the harvest rate and the time required to achieve and maintain a population size within desired bounds. We recognize, however, that regulation of absolute harvest rather than

Characteristics of Metastatic Mediastinal Lymph Nodes of Non-Small Cell Lung Cancer on Preoperative F-18 FDG PET/CT

International Nuclear Information System (INIS)

Lee, Ah Young; Choi, Su Jung; Jung, Kyung Pyo; Park, Ji Sun; Lee, Seok Mo; Bae, Sang Kyun

2014-01-01

The aim of this study was to evaluate the characteristics of PET and CT features of mediastinal metastatic lymph nodes on F-18 FDG PET/CT and to determine the diagnostic criteria in nodal staging of non-small cell lung cancer. One hundred four non-small cell lung cancer patients who had preoperative F-18 FDG PET/CT were included. For quantitative analysis, the maximum SUV of the primary tumor, maximum SUV of the lymph nodes (SUVmax), size of the lymph nodes, and average Hounsfield units (aHUs) and maximum Hounsfield units (mHUs) of the lymph nodes were measured. The SUVmax, SUV ratio of the lymph node to blood pool (LN SUV/blood pool SUV), SUV ratio of the lymph node to primary tumor (LN SUV/primary tumor SUV), size, aHU, and mHU were compared between the benign and malignant lymph nodes. Among 372 dissected lymph node stations that were pathologically diagnosed after surgery, 49 node stations were malignant and 323 node stations benign. SUVmax, LN SUV/blood pool SUV, and size were significantly different between the malignant and benign lymph node stations (P <0.0001). However, there was no significant difference in LN SUV/primary tumor SUV (P =0.18), mHU (P =0.42), and aHU (P =0.98). Using receiver-operating characteristic curve analyses, there was no significant difference among these three variables (SUVmax, LN SUV/blood pool SUV, and size). The optimal cutoff values were 2.9 for SUVmax, 1.4 for LN SUV/blood pool SUV, and 5 mm for size. When the cutoff value of SUVmax≥2.9 and size≥5 mm were used in combination, the positive predictive value was 44.2%, and the negative predictive value was 90.9 %. When we evaluated the results based on the histology of the primary tumor, the negative predictive value was 92.3 % in adenocarcinoma (cutoff values of SUVmax≥2.3 and size≥5 mm) and 97.2 % in squamous cell carcinoma (cutoff values of SUVmax≥3.6 and size≥8 mm), separately. In the lymph node staging of non-small cell lung cancer, SUVmax, LN SUV/blood pool SUV

A low frequency piezoelectric power harvester using a spiral-shaped bimorph

Institute of Scientific and Technical Information of China (English)

HU; Yuantai; HU; Hongping; YANG; Jiashi

2006-01-01

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources.A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size.It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

Analysis of Single-Server Queue with Phase-Type Service and Energy Harvesting

Directory of Open Access Journals (Sweden)

Sergey A. Dudin

2016-01-01

Full Text Available We propose a queueing model suitable, for example, for modelling operation of nodes of sensor networks. The sensor node senses a random field and generates packets to be transmitted to the central node. The sensor node has a battery of a finite capacity and harvests energy during its operation from outside (using solar cells, wind turbines, piezoelectric cells, etc.. We assume that, generally speaking, service (transmission of a packet consists of a random number of phases and implementation of each phase requires a unit of energy. If the battery becomes empty, transmission is failed. To reduce the probability of forced transmission termination, we suggest that the packet can be accepted for transmission only when the number of energy units is greater than or equal to some threshold. Under quite general assumptions about the pattern of the arrival processes of packets and energy, we compute the stationary distributions of the system states and the waiting time of a packet in the system and numerically analyze performance measures of the system as functions of the threshold. Validity of Little’s formula and its counterpart is verified.

A high-efficiency self-powered wireless sensor node for monitoring concerning vibratory events

Science.gov (United States)

Xu, Dacheng; Li, Suiqiong; Li, Mengyang; Xie, Danpeng; Dong, Chuan; Li, Xinxin

2017-09-01

This paper presents a self-powered wireless alarming sensor node (SWASN), which was designed to monitor the occurrence of concerning vibratory events. The major components of the sensor node include a vibration-threshold-triggered energy harvester (VTTEH) that powers the sensor node, a dual threshold voltage control circuit (DTVCC) for power management and a radio frequency (RF) signal transmitting module. The VTTEH generates significant electric energy only when the input vibration reaches certain amplitude. Thus, the VTTEH serves as both the power source and the vibration-event-sensing element for the sensor node. The DTVCC was specifically designed to utilize the limited power supply from the VTTEH to operate the sensor node. Constructed with only voltage detectors and MOSFETs, the DTVCC achieved low power consumption, which was 65% lower compared with the power management circuit designed in our previous work. Meanwhile, a RF transmit circuit was constructed based on the commercially available CC1110-F32 wireless transceiver chip and a compact planar antenna was designed to improve the signal transmission distance. The sensor node was fabricated and was characterized both in the laboratory and in the field. Experimental results showed that the SWASN could automatically send out alarming signals when the simulated concerning event occurred. The waiting time between two consecutive transmission periods is less than 125 s and the transmission distance can reach 1.31 km. The SWASN will have broad applications in field surveillances.

Sentinel node detection in pre-operative axillary staging.

Science.gov (United States)

Trifirò, Giuseppe; Viale, Giuseppe; Gentilini, Oreste; Travaini, Laura Lavinia; Paganelli, Giovanni

2004-06-01

The concept of sentinel lymph node biopsy in breast cancer surgery is based on the fact that the tumour drains in a logical way via the lymphatic system, from the first to upper levels. Since axillary node dissection does not improve the prognosis of patients with breast cancer, sentinel lymph node biopsy might replace complete axillary dissection for staging of the axilla in clinically N0 patients. Sentinel lymph node biopsy would represent a significant advantage as a minimally invasive procedure, considering that about 70% of patients are found to be free from metastatic disease, yet axillary node dissection can lead to significant morbidity. Subdermal or peritumoural injection of small aliquots (and very low activity) of radiotracer is preferred to intratumoural administration, and (99m)Tc-labelled colloids with most of the particles in the 100-200 nm size range would be ideal for radioguided sentinel node biopsy in breast cancer. The success rate of radioguidance in localising the sentinel lymph node in breast cancer surgery is about 97% in institutions where a high number of procedures are performed, and the success rate of lymphoscintigraphy in sentinel node detection is about 100%. The sentinel lymph node should be processed for intraoperative frozen section examination in its entirety, based on conventional histopathology and, when necessary, immune staining with anti-cytokeratin antibody. Nowadays, lymphoscintigraphy is a useful procedure in patients with different clinical evidence of breast cancer.

Experimental verification of a novel MEMS multi-modal vibration energy harvester for ultra-low power remote sensing nodes

Science.gov (United States)

Iannacci, J.; Sordo, G.; Serra, E.; Kucera, M.; Schmid, U.

2015-05-01

In this work, we discuss the verification and preliminary experimental characterization of a MEMS-based vibration Energy Harvester (EH) design. The device, named Four-Leaf Clover (FLC), is based on a circular-shaped mechanical resonator with four petal-like mass-spring cascaded systems. This solution introduces several mechanical Degrees of Freedom (DOFs), and therefore enables multiple resonant modes and deformation shapes in the vibrations frequency range of interest. The target is to realize a wideband multi-modal EH-MEMS device, that overcomes the typical narrowband working characteristics of standard cantilevered EHs, by ensuring flexible and adaptable power source to ultra-low power electronics for integrated remote sensing nodes (e.g. Wireless Sensor Networks - WSNs) in the Internet of Things (IoT) scenario, aiming to self-powered and energy autonomous smart systems. Finite Element Method simulations of the FLC EH-MEMS show the presence of several resonant modes for vibrations up to 4-5 kHz, and level of converted power up to a few μW at resonance and in closed-loop conditions (i.e. with resistive load). On the other hand, the first experimental tests of FLC fabricated samples, conducted with a Laser Doppler Vibrometer (LDV), proved the presence of several resonant modes, and allowed to validate the accuracy of the FEM modeling method. Such a good accordance holds validity for what concerns the coupled field behavior of the FLC EH-MEMS, as well. Both measurements and simulations performed at 190 Hz (i.e. out of resonance) showed the generation of power in the range of nW (Root Mean Square - RMS values). Further steps of this work will include the experimental characterization in a full range of vibrations, aiming to prove the whole functionality of the FLC EH-MEMS proposed design concept.

The Jellyfish: smart electro-active polymers for an autonomous distributed sensing node

Science.gov (United States)

Blottman, John B.; Richards, Roger T.

2006-05-01

The US Navy has recently placed emphasis on deployable, distributed sensors for Force Protection, Anti-Terrorism and Homeland Defense missions. The Naval Undersea Warfare Center has embarked on the development of a self-contained deployable node that is composed of electro-active polymers (EAP) for use in a covert persistent distributed surveillance system. Electro-Active Polymers (EAP) have matured to a level that permits their application in energy harvesting, hydrophones, electro-elastic actuation and electroluminescence. The problem to resolve is combining each of these functions into an autonomous sensing platform. The concept presented here promises an operational life several orders of magnitude beyond what is expected of a Sonobuoy due to energy conservation and harvesting, and at a reasonable cost. The embodiment envisioned is that of a deployed device resembling a jellyfish, made in most part of polymers, with the body encapsulating the necessary electronic processing and communications package and the tentacles of the jellyfish housing the sonar sensors. It will be small, neutrally buoyant, and will survey the water column much in the manner of a Cartesian Diver. By using the Electro-Active Polymers as artificial muscles, the motion of the jellyfish can be finely controlled. An increased range of detection and true node autonomy is achieved through volumetric array beamforming to focus the direction of interrogation and to null-out extraneous ambient noise.

Sentinel lymph node in breast cancer using a radiocolloid particle produced in Argentina

International Nuclear Information System (INIS)

Velazquez Espeche, M.H.; Soroa, V.E.; Castiglia, S.G. de

2004-01-01

Full text: A number of different approaches have been adopted in the application of technique to detect sentinel lymph node. The main variables are related to size of colloid used, the time to surgery following administration of the colloid, the volume of injection and the site of administration. Optimal detections of sentinel lymph node requires the use of radiopharmaceuticals which clear rapidly from the site of injection and which will be wholly retained at the level of first tier nodes. Our objective was to apply a radiocolloid particle of size between 100-220 nm produced in Argentina by CNEA and to determine its efficacy in sentinel node detections in breast cancer. The particle size was determinate by successive filtrations of a single sample through 450, 220, 100 and 20 nm pore size filters (Whatmaan, UK). The product stability was determined by chromatography controls with ITLC, The pattern of biodistribution in animal was studied in Wistar rats. Twenty female patients with breast cancer diagnosed by clinical, mammography and cytology, were investigated. Four injections of 7.4-22 MBq of 99mTc human albumin radio colloid in volume of 0.5 ml, were injected along the subcutaneous peripheral tumor margins when the tumor was palpable. Peri-subareolar subcutaneous injection in volume of 0.1 ml was also employed as an alternative in few cases. After the injection the patient massaged the injection site for about five minutes. Lymphoscintigrams were acquired in dynamic, static and transmission modes. The sentinel node was marked with a demographic pencil with the patient lying supine and with the arm on the affected side abducted at approximately 90 0 to ensure the same anatomical localization as during the surgery. During the surgery a gamma probe localized the sentinel node by count and sound. Based on the size of particles, the distribution was 90% between 100-220 nm, 7.3% between 200 and 450 nm and 2.7% less than 100 nm. The radiolabel purity was greater than

Survival benefit of post-mastectomy radiotherapy in breast carcinoma patients with T1-2 tumor and 1-3 axillary lymph node(s) metastasis

International Nuclear Information System (INIS)

Duraker, N.; Demir, D.; Bati, B.; Yilmaz, B.D.; Bati, Y.; Sobutay, E.; Caynak, Z.C.

2012-01-01

The objective of this study was to investigate the role of post-mastectomy radiotherapy in breast carcinoma patients with a tumor size of 5 cm or smaller (T1-2) and 1-3 axillary lymph node(s) metastasis (N1). We retrospectively reviewed the file records of 575 patients receiving radiotherapy (452 patients) and not receiving radiotherapy (123 patients). In the whole series, locoregional recurrence-free survival was significantly better in patients receiving radiotherapy compared with patients not receiving radiotherapy (P 0.25 and in T2N1 breast carcinoma patients with a lymph node ratio of >0.08. In patients with a lymph node ratio equal to or less than these ratios, post-mastectomy radiotherapy could be omitted to avoid radiotherapy-related risks. (author)

New strategies for SHM based on a multichannel wireless AE node

Science.gov (United States)

Godinez-Azcuaga, Valery; Ley, Obdulia

2014-03-01

This paper discusses the development of an Acoustic Emission (AE) wireless node and its application for SHM (Structural Health Monitoring). The instrument development was planned for applications monitoring steel and concrete bridges components. The final product, now commercially available, is a sensor node which includes multiple sensing elements, on board signal processing and analysis capabilities, signal conditioning electronics, power management circuits, wireless data transmission element and energy harvesting unit. The sensing elements are capable of functioning in both passive and active modes, while the multiple parametric inputs are available for connecting various sensor types to measure external characteristics affecting the performance of the structure under monitoring. The output of all these sensors are combined and analyzed at the node in order to minimize the data transmission rate, which consumes significant amount of power. Power management circuits are used to reduce the data collection intervals through selective data acquisition strategies and minimize the sensor node power consumption. This instrument, known as the 1284, is an excellent platform to deploy SHM in the original bridge applications, but initial prototypes has shown significant potential in monitoring composite wind turbine blades and composites mockups of Unmanned Autonomous Vehicles (UAV) components; currently we are working to extend the use of this system to fields such as coal flow, power transformer, and off-shore platform monitoring.

Self-powered autonomous wireless sensor node using vibration energy harvesting

International Nuclear Information System (INIS)

Torah, R; Glynne-Jones, P; Tudor, M; Beeby, S; O'Donnell, T; Roy, S

2008-01-01

This paper reports the development and implementation of an energy aware autonomous wireless condition monitoring sensor system (ACMS) powered by ambient vibrations. An electromagnetic (EM) generator has been designed to harvest sufficient energy to power a radio-frequency (RF) linked accelerometer-based sensor system. The ACMS is energy aware and will adjust the measurement/transmit duty cycle according to the available energy; this is typically every 3 s at 0.6 m s −2 rms acceleration and can be as low as 0.2 m s −2 rms with a duty cycle around 12 min. The EM generator has a volume of only 150 mm 3 producing an average power of 58 µW at 0.6 m s −2 rms acceleration at a frequency of 52 Hz. In addition, a voltage multiplier circuit is shown to increase the electrical damping compared to a purely resistive load; this allows for an average power of 120 µW to be generated at 1.7 m s −2 rms acceleration. The ACMS has been successfully demonstrated on an industrial air compressor and an office air conditioning unit, continuously monitoring vibration levels and thereby simulating a typical condition monitoring application

Defining nodes in complex brain networks

Directory of Open Access Journals (Sweden)

Matthew Lawrence Stanley

2013-11-01

Full Text Available Network science holds great promise for expanding our understanding of the human brain in health, disease, development, and aging. Network analyses are quickly becoming the method of choice for analyzing functional MRI data. However, many technical issues have yet to be confronted in order to optimize results. One particular issue that remains controversial in functional brain network analyses is the definition of a network node. In functional brain networks a node represents some predefined collection of brain tissue, and an edge measures the functional connectivity between pairs of nodes. The characteristics of a node, chosen by the researcher, vary considerably in the literature. This manuscript reviews the current state of the art based on published manuscripts and highlights the strengths and weaknesses of three main methods for defining nodes. Voxel-wise networks are constructed by assigning a node to each, equally sized brain area (voxel. The fMRI time-series recorded from each voxel is then used to create the functional network. Anatomical methods utilize atlases to define the nodes based on brain structure. The fMRI time-series from all voxels within the anatomical area are averaged and subsequently used to generate the network. Functional activation methods rely on data from traditional fMRI activation studies, often from databases, to identify network nodes. Such methods identify the peaks or centers of mass from activation maps to determine the location of the nodes. Small (~10-20 millimeter diameter spheres located at the coordinates of the activation foci are then applied to the data being used in the network analysis. The fMRI time-series from all voxels in the sphere are then averaged, and the resultant time series is used to generate the network. We attempt to clarify the discussion and move the study of complex brain networks forward. While the correct method to be used remains an open, possibly unsolvable question that

A new energy-harvesting device system for wireless sensors, adaptable to on-site monitoring of MR damper motion

International Nuclear Information System (INIS)

Yu, Miao; Peng, Youxiang; Wang, Siqi; Fu, Jie; Choi, S B

2014-01-01

Under extreme service conditions in vehicle suspension systems, some defects exist in the hardening, bodying, and poor temperature stability of magnetorheological (MR) fluid. These defects can cause weak and even invalid performance in the MR fluid damper (MR damper for short). To ensure the effective validity of the practical applicability of the MR damper, one must implement an online state-monitoring sensor to monitor several performance factors, such as acceleration. In this empirical work, we propose a new energy-harvesting device system for the wireless sensor system of an MR damper. The monitoring sensor system consists of several components, such as an energy-harvesting device, energy-management circuit, and wireless sensor node. The electrical energy harvested from the kinetic energy of the MR fluid that flows within the MR damper can be automatically charged and discharged with the help of an energy-management circuit for the wireless sensor node. After verifying good performance from each component, an experimental apparatus is built to evaluate the feasibility of the proposed self-powered wireless sensor system. The measured results of pressure, temperature, and acceleration data within the MR damper clearly demonstrate the practical applicability of monitoring the operating work states of the MR damper when it is subjected to sinusoidal excitation. (technical note)

Critical node lifetimes in random networks via the Chen-Stein method

NARCIS (Netherlands)

Franceschetti, M.; Meester, R.W.J.

2006-01-01

This correspondence considers networks where nodes are connected randomly and can fail at random times. It provides scaling laws that allow to find the critical time at which isolated nodes begin to appear in the system as its size tends to infinity. Applications are in the areas of sensor and

Wind energy harvesting with a piezoelectric harvester

International Nuclear Information System (INIS)

Wu, Nan; Wang, Quan; Xie, Xiangdong

2013-01-01

An energy harvester comprising a cantilever attached to piezoelectric patches and a proof mass is developed for wind energy harvesting, from a cross wind-induced vibration of the cantilever, by the electromechanical coupling effect of piezoelectric materials. The vibration of the cantilever under the cross wind is induced by the air pressure owing to a vortex shedding phenomenon that occurs on the leeward side of the cantilever. To describe the energy harvesting process, a theoretical model considering the cross wind-induced vibration on the piezoelectric coupled cantilever energy harvester is developed, to calculate the charge and the voltage from the harvester. The influences of the length and location of the piezoelectric patches as well as the proof mass on the generated electric power are investigated. Results show that the total generated electric power can be as high as 2 W when the resonant frequency of the cantilever harvester is close to the vortex shedding frequency. Moreover, a value of total generated electric power up to 1.02 W can be practically realized for a cross wind with a variable wind velocity of 9–10 m s −1 by a harvester with a length of 1.2 m. This research facilitates an effective and compact wind energy harvesting device. (paper)

Implications of Harvest on the Boundaries of Protected Areas for Large Carnivore Viewing Opportunities.

Directory of Open Access Journals (Sweden)

Bridget L Borg

Full Text Available The desire to see free ranging large carnivores in their natural habitat is a driver of tourism in protected areas around the globe. However, large carnivores are wide-ranging and subject to human-caused mortality outside protected area boundaries. The impact of harvest (trapping or hunting on wildlife viewing opportunities has been the subject of intense debate and speculation, but quantitative analyses have been lacking. We examined the effect of legal harvest of wolves (Canis lupus along the boundaries of two North American National Parks, Denali (DNPP and Yellowstone (YNP, on wolf viewing opportunities within the parks during peak tourist season. We used data on wolf sightings, pack sizes, den site locations, and harvest adjacent to DNPP from 1997-2013 and YNP from 2008-2013 to evaluate the relationship between harvest and wolf viewing opportunities. Although sightings were largely driven by wolf population size and proximity of den sites to roads, sightings in both parks were significantly reduced by harvest. Sightings in YNP increased by 45% following years with no harvest of a wolf from a pack, and sightings in DNPP were more than twice as likely during a period with a harvest buffer zone than in years without the buffer. These findings show that harvest of wolves adjacent to protected areas can reduce sightings within those areas despite minimal impacts on the size of protected wolf populations. Consumptive use of carnivores adjacent to protected areas may therefore reduce their potential for non-consumptive use, and these tradeoffs should be considered when developing regional wildlife management policies.

Implications of Harvest on the Boundaries of Protected Areas for Large Carnivore Viewing Opportunities.

Science.gov (United States)

Borg, Bridget L; Arthur, Stephen M; Bromen, Nicholas A; Cassidy, Kira A; McIntyre, Rick; Smith, Douglas W; Prugh, Laura R

2016-01-01

The desire to see free ranging large carnivores in their natural habitat is a driver of tourism in protected areas around the globe. However, large carnivores are wide-ranging and subject to human-caused mortality outside protected area boundaries. The impact of harvest (trapping or hunting) on wildlife viewing opportunities has been the subject of intense debate and speculation, but quantitative analyses have been lacking. We examined the effect of legal harvest of wolves (Canis lupus) along the boundaries of two North American National Parks, Denali (DNPP) and Yellowstone (YNP), on wolf viewing opportunities within the parks during peak tourist season. We used data on wolf sightings, pack sizes, den site locations, and harvest adjacent to DNPP from 1997-2013 and YNP from 2008-2013 to evaluate the relationship between harvest and wolf viewing opportunities. Although sightings were largely driven by wolf population size and proximity of den sites to roads, sightings in both parks were significantly reduced by harvest. Sightings in YNP increased by 45% following years with no harvest of a wolf from a pack, and sightings in DNPP were more than twice as likely during a period with a harvest buffer zone than in years without the buffer. These findings show that harvest of wolves adjacent to protected areas can reduce sightings within those areas despite minimal impacts on the size of protected wolf populations. Consumptive use of carnivores adjacent to protected areas may therefore reduce their potential for non-consumptive use, and these tradeoffs should be considered when developing regional wildlife management policies.

phylo-node: A molecular phylogenetic toolkit using Node.js.

Science.gov (United States)

O'Halloran, Damien M

2017-01-01

Node.js is an open-source and cross-platform environment that provides a JavaScript codebase for back-end server-side applications. JavaScript has been used to develop very fast and user-friendly front-end tools for bioinformatic and phylogenetic analyses. However, no such toolkits are available using Node.js to conduct comprehensive molecular phylogenetic analysis. To address this problem, I have developed, phylo-node, which was developed using Node.js and provides a stable and scalable toolkit that allows the user to perform diverse molecular and phylogenetic tasks. phylo-node can execute the analysis and process the resulting outputs from a suite of software options that provides tools for read processing and genome alignment, sequence retrieval, multiple sequence alignment, primer design, evolutionary modeling, and phylogeny reconstruction. Furthermore, phylo-node enables the user to deploy server dependent applications, and also provides simple integration and interoperation with other Node modules and languages using Node inheritance patterns, and a customized piping module to support the production of diverse pipelines. phylo-node is open-source and freely available to all users without sign-up or login requirements. All source code and user guidelines are openly available at the GitHub repository: https://github.com/dohalloran/phylo-node.

Experimental study of energy harvesting in UHF band

International Nuclear Information System (INIS)

Bernacki, Ł; Gozdur, R; Salamon, N

2016-01-01

A huge progress of down-sizing technology together with trend of decreasing power consumption and, on the other hand, increasing efficiency of electronics give the opportunity to design and to implement the energy harvesters as main power sources. This paper refers to the energy that can be harvested from electromagnetic field in the unlicensed frequency bands. The paper contains description of the most popular techniques and transducers that can be applied in energy harvesting domain. The overview of current research and commercial solutions was performed for bands in ultra-high frequency range, which are unlicensed and where transmission is not limited by administrative arrangements. During the experiments with Powercast’s receiver, the same bands as sources of electromagnetic field were taken into account. This power source is used for conducting radio-communication process and excess energy could be used for powering the extra electronic circuits. The paper presents elaborated prototype of energy harvesting system and the measurements of power harvested in ultra-high frequency range. The evaluation of RF energy harvesters for powering ultra-low power (ULP) electronic devices was performed based on survey and results of the experiments. (paper)

Abdominal and pelvic lymph node involvement in non-Hodgkin lymphoma: CT manifestations in Chinese patients

International Nuclear Information System (INIS)

Wu Ning; Liu Ying; Chen Yu; Lin Dongmei; Shi Mulan

2004-01-01

Objective: To study the CT manifestations of abdominal and pelvic lymph nodes in non- Hodgkin lymphoma (NHL) of Chinese patients, and to investigate their correlation with pathology subtypes. Methods: The CT images of 241 patients with enlargement of abdominal and pelvic lymph nodes involved by NHL were reviewed. Of them, 96 patients whose clinical and imaging data fulfilled the requirement for analysis were included. According to the Clinical Schema for the Lymphoid System, patients were divided into 3 subtypes, indolent lymphoma (IL; n=31), aggressive lymphoma (AL; n=61), very aggressive lymphoma (VAL; n=2), and unclassified lymphoma (UCL; n=2), respectively. Abdominal and pelvic CT scans were undertaken in 46 patients, abdominal CT only in 47 cases, and pelvic CT only in 3 cases. CT with iv contrast administration was obtained in 80 patients. Anatomic sites involved were nominated as retroperitoneal (i.e. paraaortic), abdominal (including paracardiac, gastrohepatic, hepatic hilar, and mesenteric etc), retrocrural, diaphragmatic, common iliac, internal iliac, external iliac, and inguinal nodes, respectively. Size, number, discreteness, and density of the nodal lesions were analyzed, and correlated with pathology subtypes. The minimal dimension of the largest node was measured. Results: (1) Size: Most of the nodes were ≤2 cm in size, 60.5% (219/362 sites) in IL and AL, 56.6% (77/136 sites) in IL, and 62.8%(142/226 sites) in AL, respectively. There was no statistical significant difference of the nodal size between IL and AL in each location (χ 2 =0.341, P=0.559). (2) Number: Mesentery had the largest number of node involvement (6.5 vs 5 nodes on an median, IL vs AL), with retroperitoneum placed second (4 vs 4 nodes, IL vs AL. (3) Discreteness: Most of the nodes were discrete with an incidence of 77.1% (279/362 sites, IL and AL), and 74.3% (101/136 sites) in IL, 78.8% (178/226 sites) in AL, respectively. No statistical significant discrepancy was found between

RF Energy Harvesting Peel-and-Stick Sensors

Energy Technology Data Exchange (ETDEWEB)

Lalau-Keraly, Christopher [PARC; Schwartz, David; Daniel, George; Lee, Joseph

2017-08-29

PARC, a Xerox Company, is developing a low-cost system of peel-and-stick wireless sensors that will enable widespread building environment sensor deployment with the potential to deliver up to 30% energy savings. The system is embodied by a set of RF hubs that provide power to the automatically located sensor nodes, and relays data wirelessly to the building management system (BMS). The sensor nodes are flexible electronic labels powered by rectified RF energy transmitted by a RF hub and can contain multiple printed and conventional sensors. The system design overcomes limitations in wireless sensors related to power delivery, lifetime, and cost by eliminating batteries and photovoltaic devices. The sensor localization is performed automatically by the inclusion of a programmable multidirectional antenna array in the RF hub. Comparison of signal strengths when the RF beam is swept allows for sensor localization, further reducing installation effort and enabling automatic recommissioning of sensors that have been relocated, overcoming a significant challenge in building operations. PARC has already demonstrated wireless power and temperature data transmission up to a distance of 20m with a duty cycle less than a minute between measurements, using power levels well within the FCC regulation limits in the 902-928 MHz ISM band. The sensor’s RF energy harvesting antenna dimensions was less than 5cmx9cm, demonstrating the possibility of small form factor for the sensor nodes.

Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

KAUST Repository

AlAmmouri, Ahmad

2016-07-26

Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half-duplex (HD) users\\' equipment (UEs) are required. In this context, 3-node topology (3NT) has been recently proposed for FD BSs to reuse the uplink (UL) and downlink (DL) channels with HD terminals within the same cell. In this paper, we present a tractable mathematical framework, based on stochastic geometry, for 3NT in cellular networks. To this end, we propose a design paradigm via pulse-shaping and partial overlap between UL and DL channels to maximize the harvested rate gains in 3NT. The results show that 3NT achieves a close performance to networks with FD BSs and FD UEs, denoted by 2-node topology (2NT) networks. A maximum of 5% rate loss is reported when 3NT is compared to 2NT with efficient self-interference cancellation (SIC). If the SIC in 2NT is not efficient, 3NT highly outperforms 2NT. Consequently, we conclude that, irrespective to the UE duplexing scheme, it is sufficient to have FD BSs to harvest FD rate gains.

Modeling of a piezoelectric/piezomagnetic nano energy harvester based on two dimensional theory

Science.gov (United States)

Yan, Zhi

2018-01-01

This work presents a two dimensional theory for a piezoelectric/piezomagnetic bilayer nanoplate in coupled extensional and flexural vibrations with both flexoelectric and surface effects. The magneto-electro-elastic (MEE) coupling equations are derived from three-dimensional equations and Kirchhoff plate theory. Based on the developed theory, a piezoelectric/piezomagnetic nano energy harvester is proposed, which can generate electricity under time-harmonic applied magnetic field. The approximate solutions for the mechanical responses and voltage of the energy harvester are obtained using the weighted residual method. Results show that the properties of the proposed energy harvester are size-dependent due to the flexoelectric and surface effects, and such effects are more pronounced when the bilayer thickness is reduced to dozens of nanometers. It is also found that the magnetoelectric coupling coefficient and power density of the energy harvester are sensitive to the load resistance, the thickness fraction of the piezoelectric or the piezomagnetic layer and damping ratios. Moreover, results indicate that the flexoelectric effect could be made use to build a dielectric/piezomagnetic nano energy harvester. This work provides modeling techniques and numerical methods for investigating the size-dependent properties of MEE nanoplate-based energy harvester and could be helpful for designing nano energy harvesters using the principle of flexoelectricity.

Simulation study of a single-grip harvester in thinning from below and thinning from above

Energy Technology Data Exchange (ETDEWEB)

Eliasson, Lars [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Silviculture; Lageson, Haakan [Forest Owner' s Ass. of Norrbotten, Boden (Sweden)

1999-07-01

The time consumption and productivity of a single-grip harvester were studied, using a simulation model, when thinning from below and above in eight randomly selected stands. The model estimated the time required for each work element, given machine and tree positions, and tree size. A 2 x 5 factorial design was used with factors thinning type [from below (T{sub b}) and above (T{sub a})] and tree size. Trees were subjectively selected for harvest according to thinning type. Total basal area removal was 30% plot{sup -1}. Approximately 50% more trees were harvested in T{sub b} than in T{sub a}. Time consumption tree{sup -1} was higher for T{sub a} than T{sub b}. Time consumption for machine and boom movements decreased with increasing number of harvested trees, and time for felling and processing of trees increased with harvested mean stem volume. Harvester productivity was 36% higher for T{sub a}, since the increase in harvested mean stem volume was higher than the increase in time consumption tree{sup -1}.

A Trust-Based Secure Routing Scheme Using the Traceback Approach for Energy-Harvesting Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Jiawei Tang

2018-03-01

Full Text Available The Internet of things (IoT is composed of billions of sensing devices that are subject to threats stemming from increasing reliance on communications technologies. A Trust-Based Secure Routing (TBSR scheme using the traceback approach is proposed to improve the security of data routing and maximize the use of available energy in Energy-Harvesting Wireless Sensor Networks (EHWSNs. The main contributions of a TBSR are (a the source nodes send data and notification to sinks through disjoint paths, separately; in such a mechanism, the data and notification can be verified independently to ensure their security. (b Furthermore, the data and notification adopt a dynamic probability of marking and logging approach during the routing. Therefore, when attacked, the network will adopt the traceback approach to locate and clear malicious nodes to ensure security. The probability of marking is determined based on the level of battery remaining; when nodes harvest more energy, the probability of marking is higher, which can improve network security. Because if the probability of marking is higher, the number of marked nodes on the data packet routing path will be more, and the sink will be more likely to trace back the data packet routing path and find malicious nodes according to this notification. When data packets are routed again, they tend to bypass these malicious nodes, which make the success rate of routing higher and lead to improved network security. When the battery level is low, the probability of marking will be decreased, which is able to save energy. For logging, when the battery level is high, the network adopts a larger probability of marking and smaller probability of logging to transmit notification to the sink, which can reserve enough storage space to meet the storage demand for the period of the battery on low level; when the battery level is low, increasing the probability of logging can reduce energy consumption. After the level of

A Trust-Based Secure Routing Scheme Using the Traceback Approach for Energy-Harvesting Wireless Sensor Networks.

Science.gov (United States)

Tang, Jiawei; Liu, Anfeng; Zhang, Jian; Xiong, Neal N; Zeng, Zhiwen; Wang, Tian

2018-03-01

The Internet of things (IoT) is composed of billions of sensing devices that are subject to threats stemming from increasing reliance on communications technologies. A Trust-Based Secure Routing (TBSR) scheme using the traceback approach is proposed to improve the security of data routing and maximize the use of available energy in Energy-Harvesting Wireless Sensor Networks (EHWSNs). The main contributions of a TBSR are (a) the source nodes send data and notification to sinks through disjoint paths, separately; in such a mechanism, the data and notification can be verified independently to ensure their security. (b) Furthermore, the data and notification adopt a dynamic probability of marking and logging approach during the routing. Therefore, when attacked, the network will adopt the traceback approach to locate and clear malicious nodes to ensure security. The probability of marking is determined based on the level of battery remaining; when nodes harvest more energy, the probability of marking is higher, which can improve network security. Because if the probability of marking is higher, the number of marked nodes on the data packet routing path will be more, and the sink will be more likely to trace back the data packet routing path and find malicious nodes according to this notification. When data packets are routed again, they tend to bypass these malicious nodes, which make the success rate of routing higher and lead to improved network security. When the battery level is low, the probability of marking will be decreased, which is able to save energy. For logging, when the battery level is high, the network adopts a larger probability of marking and smaller probability of logging to transmit notification to the sink, which can reserve enough storage space to meet the storage demand for the period of the battery on low level; when the battery level is low, increasing the probability of logging can reduce energy consumption. After the level of battery

Spinach seed quality - potential for combining seed size grading and chlorophyll flourescence sorting

DEFF Research Database (Denmark)

Deleuran, Lise Christina; Olesen, Merete Halkjær; Boelt, Birte

2013-01-01

might therefore improve the establishment of spinach for producers. Spinach seeds were harvested at five different times (H1, H2, H3, H4 and H5) starting 3 weeks before estimated optimum harvest time. The harvested seeds were sorted according to chlorophyll fluorescence (CF) and seed size. Two harvest.......5–3.25 mm size seeds had germinated on day 3 than both their larger and smaller counterparts at the later time of harvest (H4). Seeds with a diameter below 2.5 mm displayed the lowest MGT. Commercially, the use of chlorophyll fluorescence (CF)-sorted seeds, in combination with seed size sorting, may provide...

Node cookbook

CERN Document Server

Clements, David Mark

2014-01-01

In Node Cookbook Second Edition, each chapter focuses on a different aspect of working with Node. Following a Cookbook structure, the recipes are written in an easy-to-understand language. Readers will find it easier to grasp even the complex recipes which are backed by lots of illustrations, tips, and hints.If you have some knowledge of JavaScript and want to build fast, efficient, scalable client-server solutions, then Node Cookbook Second Edition is for you. Knowledge of Node will be an advantage but is not required. Experienced users of Node will be able to improve their skills.

Lymph node segmentation by dynamic programming and active contours.

Science.gov (United States)

Tan, Yongqiang; Lu, Lin; Bonde, Apurva; Wang, Deling; Qi, Jing; Schwartz, Lawrence H; Zhao, Binsheng

2018-03-03

Enlarged lymph nodes are indicators of cancer staging, and the change in their size is a reflection of treatment response. Automatic lymph node segmentation is challenging, as the boundary can be unclear and the surrounding structures complex. This work communicates a new three-dimensional algorithm for the segmentation of enlarged lymph nodes. The algorithm requires a user to draw a region of interest (ROI) enclosing the lymph node. Rays are cast from the center of the ROI, and the intersections of the rays and the boundary of the lymph node form a triangle mesh. The intersection points are determined by dynamic programming. The triangle mesh initializes an active contour which evolves to low-energy boundary. Three radiologists independently delineated the contours of 54 lesions from 48 patients. Dice coefficient was used to evaluate the algorithm's performance. The mean Dice coefficient between computer and the majority vote results was 83.2%. The mean Dice coefficients between the three radiologists' manual segmentations were 84.6%, 86.2%, and 88.3%. The performance of this segmentation algorithm suggests its potential clinical value for quantifying enlarged lymph nodes. © 2018 American Association of Physicists in Medicine.

Correlations of {sup 18}F-fluorothymidine uptake with pathological tumour size, Ki-67 and thymidine kinase 1 expressions in primary and metastatic lymph node colorectal cancer foci

Energy Technology Data Exchange (ETDEWEB)

Nakajo, Masatoyo; Nakajo, Masayuki [Kagoshima University, Department of Radiology, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Kajiya, Yoriko; Tani, Atsushi [Nanpuh Hospital, Department of Radiology, Kagoshima (Japan); Goto, Yuko; Higashi, Michiyo [Kagoshima University, Department of Human Pathology, Graduate School of Medical and Dental Sciences, Kagoshima, 890-8544 (Japan); Jinguji, Megumi; Fukukura, Yoshihiko [Kagoshima University, Department of Radiology, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Tanaka, Sadao [Nanpuh Hospital, Department of Pathology, Kagoshima (Japan)

2014-12-15

To examine correlations of {sup 18}F-fluorothymidine (FLT) uptake with pathological tumour size and immunohistochemical Ki-67, and thymidine kinase 1 (TK-1) expressions in primary and metastatic node colorectal cancer foci. Thirty primary cancers (PCs) and 37 metastatic nodes (MNs) were included. FLT uptake was assessed by visual scores (non-visible: 0-1 and visible: 2-4), standardized uptake value (SUV), and correlated with size, Ki-67, and TK-1. SUV was measured in visible lesions. FLT heterogeneity was assessed by visual scores (no heterogeneous uptake: 0 and heterogeneous uptake: 1-4). Forty-two lesions were visible. The visible group showed significantly higher values than the non-visible group in size, Ki-67, and TK-1 (each p < 0.05). Size correlated significantly with visual score (PC; ρ = 0.74 and MN; ρ = 0.63), SUVmax (PC; ρ = 0.49, and MN; ρ = 0.76), and SUVmean (PC; ρ = 0.40 and MN; ρ = 0.76) (each p < 0.05). Visual score correlated significantly with size (ρ = 0.86), Ki-67max (ρ = 0.35), Ki-67mean (ρ = 0.38), TK-1max (ρ = 0.35) and TK-1mean (ρ = 0.25) (each p < 0.05). No significant correlations were found between FLT uptake and Ki-67 or TK-1 in 42 visible lesions (each p > 0.05). Heterogeneous FLT uptake was noted in 73 % (22/30) of PCs. FLT uptake correlated with size. Heterogeneous FLT distribution in colorectal cancers may be one of the causes of weak or lack of FLT uptake/Ki-67 or TK-1 correlation. (orig.)

Subwavelength resonant antennas enhancing electromagnetic energy harvesting

Science.gov (United States)

Oumbe Tekam, Gabin; Ginis, Vincent; Seetharamdoo, Divitha; Danckaert, Jan

2016-04-01

In this work, an electromagnetic energy harvester operating at microwave frequencies is designed based on a cut- wire metasurface. This metamaterial is known to contain a quasistatic electric dipole resonator leading to a strong resonant electric response when illuminated by electromagnetic fields.1 Starting from an equivalent electrical circuit, we analytically design the parameters of the system to tune the resonance frequency of the harvester at the desired frequency band. Subsequently, we compare these results with numerical simulations, which have been obtained using finite elements numerical simulations. Finally, we optimize the design by investigating the best arrangement for energy harvesting by coupling in parallel and in series many single layers of cut-wire metasurfaces. We also discuss the implementation of different geometries and sizes of the cut-wire metasurface for achieving different center frequencies and bandwidths.

Lymph node hemangioma in one-humped camel

Directory of Open Access Journals (Sweden)

M.A. Aljameel

2015-12-01

Full Text Available Hemangioma is a benign tumor of blood and lymphatic vessels. It is common in skin, mucosa and soft tissues, and its occurrence in lymph nodes is extremely rare. A 10 year-old she-camel was slaughtered at Nyala slaughterhouse, South Darfur State, Sudan. Grossly, the carcass was emaciated. The left ventral superficial cervical lymph node was enlarged, hard on palpation and protruded outside the body. Its cut surface was dark red in color and measured (18 cm in diameter. Histopathologically, the sections revealed vascular masses were composed of non-encapsulated clusters of small and medium sized with thick and thin-walled, filled with blood, separated by courageous stroma and surrounded by closely packed proliferating capillaries. To the best of our knowledge, this is the first record of the left ventral superficial cervical lymph node hemangioma in a camel in the Sudan.

Harvesting and replenishment policies for renewable natural resources

Science.gov (United States)

Douglas, Aaron J.; Johnson, Richard L.

1993-01-01

The current paper links the optimal intertemporal use of renewable natural resources to the harvesting activities of various economic agents. Previous contributions cite market forces as a causative factor inducing the extirpation of renewable natural resources. The analysis given here discusses investment in the stock of renewable resources and cites important examples of this activity. By introducing joint harvesting and replenishment strategies into a model of renewable resource use, the analysis adds descriptive reality and relevance to positive and normative discussions of renewable natural resource use. A high price for the yield or a high discount rate tend to diminish the size of the optimum stationary stock of the resource with a non-replenishment harvesting strategy. Optimal non-replenishment harvesting strategies for renewable natural resources will exhaustion or extirpation of the resource if the price of the yield or the discount rate are sufficiently large. However, the availability of a replenishment technology and the use of replenishment activities tends to buffer the resource against exhaustion or extirpation.

Identification of the sentinel lymph node in patients with malignant melanoma: what are the reasons for mistakes?

International Nuclear Information System (INIS)

Vidal-Sicart, Sergi; Pons, Francesca; Puig, Susana; Vilalta, Antonio; Palou, J.M.; Castel, Teresa; Ortega, Marisa; Martin, Francisco; Rull, Ramon

2003-01-01

Scintigraphic identification of the sentinel lymph node is achievable in nearly all patients with malignant melanoma. However, in a very small number of cases the sentinel node fails to be detected, and sometimes recurrence appears during follow-up in patients who had previously tested negative for metastatic disease. The purpose of this study was to review our experience in order to isolate the reasons for erroneous sentinel lymph node identification. The evaluation involved 435 consecutive malignant melanoma patients with AJCC stages I and II (clinically negative nodes) and Breslow thickness >0.76 mm. Lymphoscintigraphy was performed the day before surgery by intradermal administration of technetium-99m labelled nanocolloid. Dynamic and static images were obtained. The sentinel node was intraoperatively identified with the aid of patent blue dye and a hand-held gamma probe. After removal, routine histopathological examination with haematoxylin-eosin (H-E) and immunohistochemistry with S 100 and HMB45 (IHC) were performed. In those patients who developed regional recurrences during follow-up, sentinel nodes were further evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR). Lymphoscintigraphy visualised at least one sentinel node in 434 out of 435 patients (99.8%). Uptake in in-transit sentinel lymph nodes was observed in 32 patients (7.4%). During surgery, localisation and removal of sentinel nodes was successful in 430/435 patients (98.8%). A total of 790 sentinel lymph nodes were harvested, with a mean of 1.8 per patient. Routine histopathological examination with H-E or IHC revealed metastatic disease in 72 patients (16.8%). During a mean follow-up of 26 months, seven of those patients with a negative sentinel node developed regional lymph node metastases. In five of them RT-PCR was positive for micrometastases within the sentinel node. In conclusion, erroneous sentinel lymph node identification can be due to changes in the surgical team

Comparison of endoscopic ultrasonography and computed tomography in detecting mediastinal and hilar lymph nodes from bronchogenic carcinoma

International Nuclear Information System (INIS)

Imamura, Masahiro; Murata, Takashi; Yoshida, Masayuki

1990-01-01

We investigated and compared the ability of CT and endoscopic ultrasonography by radial scanning (EUS) to diagnose metasasis of lung cancer to the mediastinum and hilar lymph nodes in 27 patients undergoing resection of primary lung cancer and 6 autopsy cases. We also determined the relationship between the presence or absence of metastasis and the size of each lymph node based on the lymph node size measured at the time of resection and its histopathological findings, and we then set up a standard value that was the most accurate in evaluating the presence or absence of metastasis using a receiver operating characteristics (ROC) curve. When lymph node sizes appearing as images were compared with their actual sizes measured on resected specimens before formalin fixation, the short axis measured by either method was found to generally agree with the actual values, while the long axis was slightly smaller than the actual values, although EUS gave more accurate values. When the ability to diagnose metastasis was compared between CT and EUS using the standard value obtained from the ROC curve (a more than 8 mm short axis was defined as positive for metastasis), there were no differences in the ability to delineate the entire area of the mediastinum, including hilar lymph nodes. With respect to individual sites, although there was some difficulty delineating some regions in the mediastinum (pretracheal lymph node) with EUS, more lymph nodes in the mediastinum that were delineated by EUS histopathologically had metastatic lesions than those delineated by CT. However, both methods often failed to delineate hilar lymph nodes, with no difference between the two methods. (author)

Allocating resources between network nodes for providing a network node function

NARCIS (Netherlands)

Strijkers, R.J.; Meulenhoff, P.J.

2014-01-01

The invention provides a method wherein a first network node advertises available resources that a second network node may use to offload network node functions transparently to the first network node. Examples of the first network node are a client device (e.g. PC, notebook, tablet, smart phone), a

Ultrasound differentiation of benign and malignant cervical lymph nodes

Directory of Open Access Journals (Sweden)

Md. Mizanur Rahman

2009-01-01

Full Text Available This study was conducted to see whether the size (measured by maximal short axis diameter, shape (expressed in terms of ratio dividing long axis diameter of the node by short axis diameter or L/S ratio, marginal clarity (regular or irregular margin, internal echo-pattern (homogeneous hypoechoic or heterogeneous and hilar echogenicity (presence or absence of echo-genicity in hilum are good criteria for differentiating benign from malignant cervical lymph nodes using high frequency (high resolution ultrasound probe. The study was carried out from January 1998 to December 1998, among patients with enlarged cervical lymph nodes who were scanned with a high frequency (5.0 MHz curvilinear probe. Chi-Square test was done to see the statistical correlation between two groups of nodes. A p value of <0.05 was taken as significant. Out of 65 nodes studied, 26 (100% enlarged cervical nodes with short axis diameter more than 1 cm were all malignant. In contrast 31 (79.5% of 39 enlarged nodes with short axis diameter less than 1cm were benign and rest were malignant (p<0.001. Of 34 enlarged nodes with L/S ratio <2, 30 (88.2% nodes were found malignant and 4 (11.8% were benign. Among the rest 31 enlarged nodes, 27 (87.1% with L/S ratio  2 were benign while 4 (12.9% were malignant (p <0.001. Among the 39 nodes with regular margin 28 (71.8% were found benign, where as among 26 nodes with irregular margin 23 (88.5% were malignant (p <0.001. When the internal echopattern was taken in account, 32 nodes had homogeneous hypoechoic echo of which 28 (87.5% were benign and among 33 nodes with heterogeneous echopattern 30 (90.9% were malignant (p <0.001. Among the 43 enlarged nodes with presence of hilar echogenicity 31(72.1% were found benign and 22 (100% nodes with no hilar echogenicity were all malignant (p <0.001. Such findings suggest that real time high resolution ultrasound might assist in differentiation of benign and malignant enlarged cervical lymph nodes

Outage Probability Minimization for Energy Harvesting Cognitive Radio Sensor Networks

Directory of Open Access Journals (Sweden)

Fan Zhang

2017-01-01

Full Text Available The incorporation of cognitive radio (CR capability in wireless sensor networks yields a promising network paradigm known as CR sensor networks (CRSNs, which is able to provide spectrum efficient data communication. However, due to the high energy consumption results from spectrum sensing, as well as subsequent data transmission, the energy supply for the conventional sensor nodes powered by batteries is regarded as a severe bottleneck for sustainable operation. The energy harvesting technique, which gathers energy from the ambient environment, is regarded as a promising solution to perpetually power-up energy-limited devices with a continual source of energy. Therefore, applying the energy harvesting (EH technique in CRSNs is able to facilitate the self-sustainability of the energy-limited sensors. The primary concern of this study is to design sensing-transmission policies to minimize the long-term outage probability of EH-powered CR sensor nodes. We formulate this problem as an infinite-horizon discounted Markov decision process and propose an ϵ-optimal sensing-transmission (ST policy through using the value iteration algorithm. ϵ is the error bound between the ST policy and the optimal policy, which can be pre-defined according to the actual need. Moreover, for a special case that the signal-to-noise (SNR power ratio is sufficiently high, we present an efficient transmission (ET policy and prove that the ET policy achieves the same performance with the ST policy. Finally, extensive simulations are conducted to evaluate the performance of the proposed policies and the impaction of various network parameters.

Precautionary harvest policies and the uncertainty paradox

NARCIS (Netherlands)

Cadrin, S.X.; Pastoors, M.A.

2008-01-01

Elements of the precautionary approach to fishery management are commonly implemented in the form of harvest control rules, with limit, threshold and target reference points for stock size and fishing mortality. However, a review of two large advisory and management systems indicates that many stock

Adaptive Security in ODMAC for Multihop Energy Harvesting Wireless Sensor Networks

DEFF Research Database (Denmark)

Di Mauro, Alessio; Fafoutis, Xenofon; Dragoni, Nicola

2015-01-01

Energy Harvesting Wireless Sensor Networks (EH-WSNs) represent an interesting new paradigm where individual nodes forming a network are powered by energy sources scavenged from the surrounding environment. This technique provides numerous advantages, but also new design challenges. Securing...... the communications under energy constraints represents one of these key challenges. The amount of energy available is theoretically infinite in the long run but highly variable over short periods of time, and managing it is a crucial aspect. In this paper we present an adaptive approach for security in multihop EH...

Faecal particle-size distribution from ewes fed grass silages harvested at different stages of maturity

DEFF Research Database (Denmark)

Jalali, Alireza; Nørgaard, Peder; Nadeau, E.

2008-01-01

The aim of this experiment was to study the effect of maturity stage of grass at harvest on particle size in faeces from ewes fed grass silage ad libitum. Eighteen pregnant Swedish ewes bearing two foetuses were given one of three treatments as their only feed. The treatments were early (ECS......), medium (MCS) or late (LCS) cut grass silage. The ECS, MCS and LCS silages contained 449, 578, and 634 g NDF kg-1 and 166, 111 and 81 g crude protein kg-1 DM, respectively. The in situ rumen indigestible NDF (INDF) was 77, 164 and 268 g kg-1 of NDF; the degradation rate of digestible NDF (kdDNDF) was 64......, 47 and 44 g kg-1 h-1 and DM intake was 2.5, 2.1 and 1.5 kg d-1 for ECS, MCS and LCS silage, respectively. Faeces samples were collected during four days, washed in nylon bags, freeze dried and sieved into six sieving fractions; bottom bowl (B), 0.106 (C), 0.212 (D), 0.5 (S), 1.0 (M) and 2.36 (O) mm...

Protograph LDPC Codes with Node Degrees at Least 3

Science.gov (United States)

Divsalar, Dariush; Jones, Christopher

2006-01-01

In this paper we present protograph codes with a small number of degree-3 nodes and one high degree node. The iterative decoding threshold for proposed rate 1/2 codes are lower, by about 0.2 dB, than the best known irregular LDPC codes with degree at least 3. The main motivation is to gain linear minimum distance to achieve low error floor. Also to construct rate-compatible protograph-based LDPC codes for fixed block length that simultaneously achieves low iterative decoding threshold and linear minimum distance. We start with a rate 1/2 protograph LDPC code with degree-3 nodes and one high degree node. Higher rate codes are obtained by connecting check nodes with degree-2 non-transmitted nodes. This is equivalent to constraint combining in the protograph. The condition where all constraints are combined corresponds to the highest rate code. This constraint must be connected to nodes of degree at least three for the graph to have linear minimum distance. Thus having node degree at least 3 for rate 1/2 guarantees linear minimum distance property to be preserved for higher rates. Through examples we show that the iterative decoding threshold as low as 0.544 dB can be achieved for small protographs with node degrees at least three. A family of low- to high-rate codes with minimum distance linearly increasing in block size and with capacity-approaching performance thresholds is presented. FPGA simulation results for a few example codes show that the proposed codes perform as predicted.

Design Optimization of a Magnetically Levitated Electromagnetic Vibration Energy Harvester for Body Motion

Science.gov (United States)

Pancharoen, K.; Zhu, D.; Beeby, S. P.

2016-11-01

This paper presents a magnetically levitated electromagnetic vibration energy harvester based on magnet arrays. It has a nonlinear response that extends the operating bandwidth and enhances the power output of the harvesting device. The harvester is designed to be embedded in a hip prosthesis and harvest energy from low frequency movements (< 5 Hz) associated with human motion. The design optimization is performed using Comsol simulation considering the constraints on size of the harvester and low operating frequency. The output voltage across the optimal load 3.5kΩ generated from hip movement is 0.137 Volts during walking and 0.38 Volts during running. The power output harvested from hip movement during walking and running is 5.35 μW and 41.36 μW respectively..

Structural alterations in tumor-draining lymph nodes before papillary thyroid carcinoma metastasis.

Science.gov (United States)

Hinson, Andrew M; Massoll, Nicole A; Jolly, Lee Ann; Stack, Brendan C; Bodenner, Donald L; Franco, Aime T

2017-08-01

The purpose of this study was to define and characterize the thyroid tumor-draining lymph nodes in genetically engineered mice harboring thyroid-specific expression of oncogenic Braf V600E with and without Pten insufficiency. After intratumoral injection of methylene blue, the lymphatic drainage of the thyroid gland was visualized in real time. The thyroid gland/tumor was resected en bloc with the respiratory system for histological analysis. Although mice harboring Braf V600E mutations were smaller in body size compared with their wild-type (WT) littermates, the size of their thyroid glands and deep cervical lymph nodes were significantly larger. Additionally, the tumor-draining lymph nodes showed increased and enlarged lymphatic sinuses that were distributed throughout the cortex and medulla. Tumor-reactive lymphadenopathy and histiocytosis, but no frank metastases, were observed in all mice harboring Braf V600E mutations. The tumor-draining lymph nodes undergo significant structural alterations in immunocompetent mice, and this may represent a primer for papillary thyroid carcinoma (PTC) metastasis. © 2017 Wiley Periodicals, Inc.

Allocating resources between network nodes for providing a network node function

OpenAIRE

Strijkers, R.J.; Meulenhoff, P.J.

2014-01-01

The invention provides a method wherein a first network node advertises available resources that a second network node may use to offload network node functions transparently to the first network node. Examples of the first network node are a client device (e.g. PC, notebook, tablet, smart phone), a server (e.g. application server, a proxy server, cloud location, router). Examples of the second network node are an application server, a cloud location or a router. The available resources may b...

Numeric pathologic lymph node classification shows prognostic superiority to topographic pN classification in esophageal squamous cell carcinoma.

Science.gov (United States)

Sugawara, Kotaro; Yamashita, Hiroharu; Uemura, Yukari; Mitsui, Takashi; Yagi, Koichi; Nishida, Masato; Aikou, Susumu; Mori, Kazuhiko; Nomura, Sachiyo; Seto, Yasuyuki

2017-10-01

numbers of lymph nodes were harvested. Copyright © 2017 Elsevier Inc. All rights reserved.

50 CFR 640.21 - Harvest limitations.

Science.gov (United States)

2010-10-01

... § 640.21 Harvest limitations. (a) Berried lobsters. A berried (egg-bearing) spiny lobster or slipper...) Undersized attractants. A live spiny lobster under the minimum size limit specified in paragraph (b)(1) of... future use as an attractant in a trap provided it is held in a live well aboard the vessel. No more than...

Node-pair reliability of network systems with small distances between adjacent nodes

International Nuclear Information System (INIS)

Malinowski, Jacek

2007-01-01

A new method for computing the node-pair reliability of network systems modeled by random graphs with nodes arranged in sequence is presented. It is based on a recursive algorithm using the 'sliding window' technique, the window being composed of several consecutive nodes. In a single step, the connectivity probabilities for all nodes included in the window are found. Subsequently, the window is moved one node forward. This process is repeated until, in the last step, the window reaches the terminal node. The connectivity probabilities found at that point are used to compute the node-pair reliability of the network system considered. The algorithm is designed especially for graphs with small distances between adjacent nodes, where the distance between two nodes is defined as the absolute value of the difference between the nodes' numbers. The maximal distance between any two adjacent nodes is denoted by Γ(G), where G symbolizes a random graph. If Γ(G)=2 then the method can be applied for directed as well as undirected graphs whose nodes and edges are subject to failure. This is important in view of the fact that many algorithms computing network reliability are designed for graphs with failure-prone edges and reliable nodes. If Γ(G)=3 then the method's applicability is limited to undirected graphs with reliable nodes. The main asset of the presented algorithms is their low numerical complexity-O(n), where n denotes the number of nodes

Comparison between ultrasonography and MR imaging for discriminating squamous cell carcinoma nodes with extranodal spread in the neck

International Nuclear Information System (INIS)

Katayama, Ikuo; Sasaki, Miho; Kimura, Yasuo; Hotokezaka, Yuka; Eida, Sato; Tashiro, Shigeki; Sumi, Misa; Nakamura, Takashi

2012-01-01

Objective: To compare the diagnostic ability of ultrasonography (US) and MR imaging for discriminating squamous cell carcinoma (SCC) nodes with extranodal spread (ENS) in the neck. Methods: US and MR imaging was retrospectively evaluated for differentiating ENS-positive (n = 28) from ENS-negative (n = 26) SCC nodes (>10 mm short-axis diameter) in 50 patients with head and neck SCCs. We assessed nodal size on US and MR images; irregular nodal margin on US; and vanishing nodal border, flare, and shaggy nodal margin signs on T1-, fat-suppressed T2-, and contrast-enhanced T1-weighted MR images, respectively. US and MR images were analyzed by 3 radiologists in consensus and the results were compared between ENS-positive and ENS-negative SCC nodes. Results: The nodal sizes of ENS-positive nodes (21 ± 9 mm) were significantly larger than those of ENS-negative SCC nodes (14 ± 4 mm) (p < 0.001). Irregular nodal margins were more frequently observed in ENS-positive SCC nodes (75%) than in ENS-negative SCC nodes (12%). The vanishing nodal margin, flare, and shaggy nodal margin signs were more frequently observed in ENS-positive SCC nodes (93%, 89%, and 82%, respectively) than in ENS-negative nodes (46%, 19%, and 19%, respectively). A combination of size (≥22 mm) and imaging criteria (irregular margin or flare sign) best discriminated ENS-positive SCC nodes with 82% sensitivity, 89% specificity, and 85% accuracy for US and 89% sensitivity, 81% specificity, and 85% accuracy for MR imaging. Conclusion: US discriminated ENS-positive from ENS-negative SCC nodes with comparable accuracy and higher specificity than MR imaging.

Stage migration after introduction of sentinel lymph node dissection in breast cancer treatment in Denmark: a nationwide study

DEFF Research Database (Denmark)

Tvedskov, Tove Filtenborg; Jensen, Maj-Britt; Balslev, Eva

2011-01-01

To estimate the size and therapeutic consequences of stage migration after introduction of sentinel lymph node dissection (SLND) in breast cancer treatment in Denmark.......To estimate the size and therapeutic consequences of stage migration after introduction of sentinel lymph node dissection (SLND) in breast cancer treatment in Denmark....

Analysis of the movement of calcified lymph nodes during breathing

International Nuclear Information System (INIS)

Jenkins, Peter; Salmon, Clare; Mannion, Cathy

2005-01-01

Purpose: To identify and measure the respiratory-induced movement of calcified mediastinal lymph nodes. Methods and materials: Twenty-one patients receiving radiation therapy for primary lung or pleural tumors were noted to have calcification within one or more mediastinal lymph nodes. The breathing motion of 27 such nodes was measured with orthogonal fluoroscopic imaging during quiet respiration. Results: All 27 nodes showed some motion synchronous with breathing. The mean respiratory movement was 6.6 mm, 2.6 mm, and 1.4 mm in the craniocaudal, dorsoventral, and mediolateral planes, respectively. There was a significant difference in the amplitude of motion in the craniocaudal plane compared with movement in the other two directions (p < 0.001). No differences were seen in the movement of lymph nodes dependent on position within the mediastinum (supracarinal vs. infracarinal or hilar vs. mediastinal). Neither size of the primary tumor nor spirometric parameters were correlated with the amplitude of lymph node movement. Conclusions: Mediastinal lymph nodes move during breathing, and this needs to be accounted for when the internal margin component of the PTV is defined. The amplitude of this movement is anisotropic and seems to be less than that reported for primary lung tumors. This should permit a modest reduction in the margin allowed for breathing movement around involved mediastinal nodes, particularly in the mediolateral and dorsoventral planes

The Dynamical Mechanisms of the Cell Cycle Size Checkpoint

International Nuclear Information System (INIS)

Feng Shi-Fu; Yang Ling; Yan Jie; Liu Zeng-Rong

2012-01-01

Cell division must be tightly coupled to cell growth in order to maintain cell size, whereas the mechanisms of how initialization of mitosis is regulated by cell size remain to be elucidated. We develop a mathematical model of the cell cycle, which incorporates cell growth to investigate the dynamical properties of the size checkpoint in embryos of Xenopus laevis. We show that the size checkpoint is naturally raised from a saddle-node bifurcation, and in a mutant case, the cell loses its size control ability due to the loss of this saddle-node point

Comparison of systematic mediastinal lymph node dissection versus systematic sampling for lung cancer staging and completeness of surgery.

Science.gov (United States)

Wu, Nan; Yan, Shi; Lv, Chao; Feng, Yuan; Wang, Yuzhao; Zhang, Lijian; Yang, Yue

2011-12-01

This self-controlled prospective study was designed to investigate the efficacy of systematic sampling (SS), compared with systematic mediastinal lymph node dissection (SMLD), for pathologic staging and completeness of surgery. Over a period of 11 mo, 110 patients with lung cancer were enlisted and treated by pulmonary resection. Surgeons systematically sampled mediastinal lymph nodes prior to pulmonary resection, and after pulmonary resection SMLD was performed to each patient using Mountain's procedure [1]. After SMLD, pN status was classified as N0 in 57 cases, N1 in 27, and N2 in 26. SS detected 38.3% of pooled nodes and 37.6% of pooled positive nodes collected from SMLD. Pathologic diagnosis after SS was understaged in nine cases (8.2%) compared with staging after SMLD. However, surgery was incomplete in 24 cases (21.8%) if SMLD was not performed after sampling. Negative predictive value for SS was 86.8% on the right side, and 95.0% on the left. Three categories were generated according to pN status: negative nodes in SS and additional negative nodes from SMLD [S(-)D(-)], negative nodes in SS but additional positive nodes from SMLD [S(-)D(+)], and positive nodes in SS [S(+)D(+)]. cN2 (P=0.000) and CEA level (P=0.001) were correlated with pN status. There was significant overall survival difference between non-N2 group and N2 group (P=0.002). SMLD may harvest about three times of mediastinal lymph nodes compared with SS. SS is more likely to affect the completeness of surgery instead of underrating pathologic stage. Copyright © 2011 Elsevier Inc. All rights reserved.

Looped energy harvester for human motion

Science.gov (United States)

Geisler, M.; Boisseau, S.; Gasnier, P.; Willemin, J.; Gobbo, C.; Despesse, G.; Ait-Ali, I.; Perraud, S.

2017-10-01

The development of energy harvesters for smart wearables is a challenging topic, with a difficult combination of ergonomics constraints, lifetime and electrical requirements. In this work, we focus on an inertial inductive structure, composed of a magnetic ball circulating inside a closed-loop guide and converting the kinetic energy of the user’s limbs into electricity during the run. A specific induction issue related to the free self-rotation of the ball is underlined and addressed using a ferromagnetic ‘rail’ component. From a 2 g moving ball, a 5 cm-diameter 21 cm3 prototype generated up to 4.8 mW of average power when worn by someone running at 8 km h-1. This device is demonstrated to charge a 2.4 V NiMH battery and supply an acceleration and temperature Wireless Sensor Node at 20 Hz.

An energy-harvesting power supply for underwater bridge scour monitoring sensors

Science.gov (United States)

Wang, Yuli; Li, Yingjie; He, Longzhuang; Shamsi, Pourya; Zheng, Yahong R.

2018-03-01

The natural force of scouring has become one of the most critical risk endangering the endurance of bridges, thus leading to the necessity of deploying underwater monitoring sensors to actively detect potential scour holes under bridges. Due to the difficulty in re-charging batteries for underwater sensors, super capacitors with energy harvesting (EH) means are exploited to prolong the sustainability of underwater sensors. In this paper, an energy harvesting power supply based on a helical turbine is proposed to power underwater monitoring sensors. A small helical turbine is designed to convert water flow energy to electrical energy with favorable environmental robustness. A 3-inch diameter, 2.5-inch length and 3-bladed helical turbine was designed with two types of waterproof coupling with the sensor housing. Both designs were prototyped and tested under different flow conditions and we get valid voltage around 0.91 V which is enough to power monitoring sensor. The alternating current (AC) electrical energy generated by the helical turbine is then rectified and boosted to drive a DC charger for efficiently charging one super capacitor. The charging circuit was designed, prototyped and tested thoroughly with the helical turbine harvester. The results were promising, that the overall power supply can power an underwater sensor node with wireless transceivers for long-term operations

Image-guided core-needle biopsy of peripheral lymph nodes allows the diagnosis of lymphomas

International Nuclear Information System (INIS)

Kerviler, Eric de; Bazelaire, Cedric de; Mathieu, Olivier; Frija, Jacques; Mounier, Nicolas; Gisselbrecht, Christian; Brethon, Benoit; Briere, Josette; Marolleau, Jean-Pierre; Brice, Pauline

2007-01-01

It is commonly admitted that the diagnosis of lymphomas can be assessed by the image-guided needle biopsy (IGNB) of deep lymph nodes. However, when peripheral lymph nodes are present, surgical dissection remains the standard strategy. The aim of this study was to evaluate the diagnostic yield of IGNB of peripheral lymph nodes in patients with suspected lymphomas. The records of 180 multisampling IGNBs of peripheral lymph nodes in 180 patients were reviewed. One hundred and twenty-three IGNBs were observed at first diagnosis and 57 at progression using large-cutting core-biopsy needles ranging between 18 G and 14 G in size. Immunohistochemistry studies were performed in all cases and at least one biopsy was systematically frozen. A diagnosis of lymphoma with sufficient information such that a therapeutic decision could be made was obtained in 146 of the 152 patients with lymphoproliferative disorders (96%). IGNB was equally effective in making the correct diagnosis of lymphoma at the time of original diagnosis than at relapse. The results did not depend on the biopsy site, lymph nodes size, or needle type. We recommend that IGNB may be performed as an initial procedure for the diagnosis of lymphomas either in the presence of peripheral or deep lymph nodes, as it avoids surgery. (orig.)

Effect of a size-selective biomanipulation on nutrient release by gizzard shad in Florida (USA lakes

Directory of Open Access Journals (Sweden)

Schaus M.H.

2013-11-01

Full Text Available Although fish removal for biomanipulation is often highly size-selective, our understanding of the nutrient cycling effects of this size-selection is poor. To better understand these effects, we measured nutrient excretion by gizzard shad (Dorosoma cepedianum of differing sizes from four central Florida (USA lakes and combined these measures with gillnet biomass and size-structure data to compare lake-wide effects among lakes and years. Direct removal of P in fish tissue ranged from 0.16−1.00 kg·P·ha-1·yr-1. The estimated reduction in P excretion due to harvest ranged from 30.8−202.5 g·P·ha-1·month-1, with effects strongly tied to the biomass and size structure harvested. The amount of P release prevented per kg of fish removed was lower in previously unharvested lakes, due to the initial removal of larger fish with lower mass-specific excretion rates. Gill net mesh size impacted the size distribution of harvested fish, with smaller fish that excrete more P per gram being more vulnerable to smaller mesh sizes. In Lake Apopka, decreasing the mesh size by 1.3 cm yielded P excretion reductions that were 10.7−15.1% larger. Fish harvesting to reduce internal nutrient cycling can be most effective by increasing total harvest and by harvesting smaller size classes over multiple years.

Sustainability of Mangrove Harvesting: How do Harvesters' Perceptions Differ from Ecological Analysis?

Directory of Open Access Journals (Sweden)

Laura López-Hoffman

2006-12-01

Full Text Available To harvest biological resources sustainably, it is first necessary to understand what "sustainability" means in an ecological context, and what it means to the people who use the resources. As a case study, we examined the extractive logging of the mangrove Rhizophora mangle in the Río Limón area of Lake Maracaibo, in western Venezuela. The ecological definition of sustainable harvesting is harvesting that allows population numbers to be maintained or to increase over time. In interviews, the harvesters defined sustainable harvesting as levels permitting the maintenance of the mangrove population over two human generations, about 50 yr. In Río Limón, harvesters extract a combination of small adult and juvenile trees. Harvesting rates ranged from 7-35% of small adult trees. These harvesting levels would be sustainable according to the harvester's definition as long as juvenile harvesting was less than 40%. However, some harvesting levels that would be sustainable according to the harvesters were ecologically unsustainable, i.e., eventually causing declines in mangrove population numbers. It was also determined that the structure of mangrove forests was significantly affected by harvesting; even areas harvested at low, ecologically sustainable intensities had significantly fewer adult trees than undisturbed sites. Western Venezuela has no organized timber industry, so mangrove logs are used in many types of construction. A lagging economy and a lack of alternative construction materials make mangrove harvesting inevitable, and for local people, an economic necessity. This creates a trade-off between preserving the ecological characteristics of the mangrove population and responding to human needs. In order to resolve this situation, we recommended a limited and adaptive mangrove harvesting regime. We also suggest that harvesters could participate in community-based management programs as harvesting monitors.

Machinery management data for willow harvest with a bio-baler

Energy Technology Data Exchange (ETDEWEB)

Savoie, P. [Agriculture and Agri-Food Canada, Quebec City, PQ (Canada); Hebert, P.L. [Laval Univ., Quebec City, PQ (Canada). Dept. des sols et de genie agroalimentaire; Robert, F.S. [Laval Univ., Quebec City, PQ (Canada). Sols et environnement

2010-07-01

Willow harvested in 2-to-3-year rotations has been touted as a reliable source of biomass. A newly designed harvester based on a round baler was developed in 2006. The third generation biobaler was evaluated in 2009 at 2 willow plantations in Quebec. The first site at Godmanchester was a three-year old regrowth with an estimated 52,000 stems/ha of large diameter willow. The biobaler with a flail cutter harvested three plots totalling 4,136 m{sup 2}. Total harvested biomass was 10.36 t DM in 42 bales. The harvest rate averaged 29 bale/h with an average bale size of 1.22 m wide by 1.30 m in diameter. Diesel fuel consumption averaged 0.81 L/bale. Measured losses averaged 11 per cent of the yield. The second site at Saint-Roch-del'Achigan was a two-year old growth with an estimated 49,000 stems/ha of large stem willow. The biobaler harvested seven plots totalling 15,740 m{sup 2}. Total harvest was 30.70 t DM in 148 bales. The first 14 bales were harvested with a saw blade header. All other bales were harvested with the flail cutter at a faster rate. Bale density averaged 129 kg DM/m{sup 3}. Fuel consumption averaged 0.72 L/bale. Losses averaged 20 per cent of the yield with the saw blade header.

Palm harvest impacts in north-western South America

DEFF Research Database (Denmark)

Balslev, Henrik

2011-01-01

Tropical forests harbor thousands of useful plants that are harvested and used in subsistence economies or traded in local, regional or international markets. The effect on the ecosystem is little known, and the forests resilience is badly understood. Palms are the most useful group of plants...... in tropical American forests. This paper introduces a cross-disciplinary study of the effects of harvesting palm products from the tropical forests in north-western South America. The size of the resource is estimated through palm community studies in the different forest formations that determines the number...... of species and individuals of all palm species. The genetic structure of useful palm species is studied to determine how much harvesting of the species contributes to genetic erosion of its populations, and whether extraction can be made without harm. Almost all palm species are used in rural communities...

Factors Predictive of Sentinel Lymph Node Involvement in Primary Breast Cancer.

Science.gov (United States)

Malter, Wolfram; Hellmich, Martin; Badian, Mayhar; Kirn, Verena; Mallmann, Peter; Krämer, Stefan

2018-06-01

Sentinel lymph node biopsy (SLNB) has replaced axillary lymph node dissection (ALND) for axillary staging in patients with early-stage breast cancer. The need for therapeutic ALND is the subject of ongoing debate especially after the publication of the ACOSOG Z0011 trial. In a retrospective trial with univariate and multivariate analyses, factors predictive of sentinel lymph node involvement should be analyzed in order to define tumor characteristics of breast cancer patients, where SLNB should not be spared to receive important indicators for adjuvant treatment decisions (e.g. thoracic wall irradiation after mastectomy with or without reconstruction). Between 2006 and 2010, 1,360 patients with primary breast cancer underwent SLNB with/without ALND with evaluation of tumor localization, multicentricity and multifocality, histological subtype, tumor size, grading, lymphovascular invasion (LVI), and estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 status. These characteristics were retrospectively analyzed in univariate and multivariate logistic regression models to define significant predictive factors for sentinel lymph node involvement. The multivariate analysis demonstrated that tumor size and LVI (pbreast cancer. Because of the increased risk for metastatic involvement of axillary sentinel nodes in cases with larger breast cancer or diagnosis of LVI, patients with these breast cancer characteristics should not be spared from SLNB in a clinically node-negative situation in order to avoid false-negative results with a high potential for wrong indication of primary breast reconstruction or wrong non-indication of necessary post-mastectomy radiation therapy. The prognostic impact of avoidance of axillary staging with SLNB is analyzed in the ongoing prospective INSEMA trial. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

The case for energy harvesting on wildlife in flight

International Nuclear Information System (INIS)

Shafer, Michael W; MacCurdy, Robert; Garcia, Ephrahim; Shipley, J Ryan; Winkler, David; Guglielmo, Christopher G

2015-01-01

The confluence of advancements in microelectronic components and vibrational energy harvesting has opened the possibility of remote sensor units powered solely from the motion of their hosts. There are numerous applications of such systems, including the development of modern wildlife tracking/data-logging devices. These ‘bio-logging’ devices are typically mass-constrained because they must be carried by an animal. Thus, they have historically traded scientific capability for operational longevity due to restrictions on battery size. Recently, the precipitous decrease in the power requirements of microelectronics has been accompanied by advancements in the area of piezoelectric vibrational energy harvesting. These energy harvesting devices are now capable of powering the type of microelectronic circuits used in bio-logging devices. In this paper we consider the feasibility of employing these vibrational energy harvesters on flying vertebrates for the purpose of powering a bio-logging device. We show that the excess energy available from birds and bats could be harvested without adversely affecting their overall energy budget. We then present acceleration measurements taken on flying birds in a flight tunnel to understand modulation of flapping frequency during steady flight. Finally, we use a recently developed method of estimating the maximum power output from a piezoelectric energy harvester to determine the amount of power that could be practically harvested from a flying bird. The results of this analysis show that the average power output of a piezoelectric energy harvester mounted to a bird or bat could produce more than enough power to run a bio-logging device. We compare the power harvesting capabilities to the energy requirements of an example system and conclude that vibrational energy harvesting on flying birds and bats is viable and warrants further study, including testing. (paper)

Normal mediastinal and hilar lymph nodes evaluated by 5 mm slice bolus injection CT scan

International Nuclear Information System (INIS)

Yamamoto, Takako; Tsukada, Hiroshi; Koizumi, Naoya; Akita, Shinichi; Oda, Junichi; Sakai, Kunio

1995-01-01

We evaluated the number and size of normal mediastinal and hilar lymph nodes by 5 mm slice bolus injection CT (12 patients), compared with 10 mm slice CT (12 patients). More lymph nodes were clearly demonstrated by 5 mm slice CT than by 10 mm slice CT. Especially left-sided tracheobronchial (no.4), subaortic (no.5), subcarinal (no.7) and hilar lymph nodes were clearly visible. We concluded 5 mm slice bolus injection CT was useful to evaluate mediastinal and hilar lymph nodes. (author)

Prevalence of enlarged mediastinal lymph nodes in heavy smokers - a comparative study

Energy Technology Data Exchange (ETDEWEB)

Kirchner, Johannes; Lorenz, Vivian-Wilma [Allgemeines Krankenhaus Hagen, Department of Diagnostic and Interventional Radiology, Hagen (Germany); Kirchner, Esther Maria [Staedtisches Klinikum Wedau, Clinic for Medicine, Duisburg (Germany); Goltz, Jan Peter; Kickuth, Ralph [University Hospital of Wuerzburg, Department of Radiology, Wuerzburg (Germany)

2011-08-15

To evaluate the frequency of enlarged hilar or mediastinal lymph nodes in heavy smokers (more than 10 pack years) compared with non- smokers. In a prospective study the CT findings of 88 consecutive patients (44 heavy smokers, 44 non- smokers) were analysed. Exclusion criteria were history of thoracic malignancy, sarcoidosis, occupational dust exposure or clinical evidence of pneumonia. Prevalence, size and site of enlarged lymph nodes were assessed by multidetector computed tomography (MDCT) and correlated with the cigarette consumption and the CT- findings of bronchitis and emphysema. Twenty-three of the 44 heavy smokers (52%) showed enlarged mediastinal lymph nodes. Non- smokers showed enlarged lymph nodes in 9% (4/44). The most common site of enlarged lymph nodes was the regional station 7 according to the ATS mapping (subcarinal). The difference between the frequency of enlarged lymph nodes in heavy smokers and non- smokers was significant (chi- square 19.3, p < 0.0001). Airway wall thickening and emphysema were often associated with an increased number of enlarged nodes. The present study demonstrates that enlarged mediastinal lymph nodes may occur in a rather high percentage of heavy smokers, especially in those with a MDCT finding of severe bronchitis. (orig.)

Prevalence of enlarged mediastinal lymph nodes in heavy smokers - a comparative study

International Nuclear Information System (INIS)

Kirchner, Johannes; Lorenz, Vivian-Wilma; Kirchner, Esther Maria; Goltz, Jan Peter; Kickuth, Ralph

2011-01-01

To evaluate the frequency of enlarged hilar or mediastinal lymph nodes in heavy smokers (more than 10 pack years) compared with non- smokers. In a prospective study the CT findings of 88 consecutive patients (44 heavy smokers, 44 non- smokers) were analysed. Exclusion criteria were history of thoracic malignancy, sarcoidosis, occupational dust exposure or clinical evidence of pneumonia. Prevalence, size and site of enlarged lymph nodes were assessed by multidetector computed tomography (MDCT) and correlated with the cigarette consumption and the CT- findings of bronchitis and emphysema. Twenty-three of the 44 heavy smokers (52%) showed enlarged mediastinal lymph nodes. Non- smokers showed enlarged lymph nodes in 9% (4/44). The most common site of enlarged lymph nodes was the regional station 7 according to the ATS mapping (subcarinal). The difference between the frequency of enlarged lymph nodes in heavy smokers and non- smokers was significant (chi- square 19.3, p < 0.0001). Airway wall thickening and emphysema were often associated with an increased number of enlarged nodes. The present study demonstrates that enlarged mediastinal lymph nodes may occur in a rather high percentage of heavy smokers, especially in those with a MDCT finding of severe bronchitis. (orig.)

Designing A General Deep Web Harvester by Harvestability Factor

NARCIS (Netherlands)

Khelghati, Mohammadreza; van Keulen, Maurice; Hiemstra, Djoerd

2014-01-01

To make deep web data accessible, harvesters have a crucial role. Targeting different domains and websites enhances the need of a general-purpose harvester which can be applied to different settings and situations. To develop such a harvester, a large number of issues should be addressed. To have

Desert Beetle-Inspired Superwettable Patterned Surfaces for Water Harvesting.

Science.gov (United States)

Yu, Zhenwei; Yun, Frank F; Wang, Yanqin; Yao, Li; Dou, Shixue; Liu, Kesong; Jiang, Lei; Wang, Xiaolin

2017-09-01

With the impacts of climate change and impending crisis of clean drinking water, designing functional materials for water harvesting from fog with large water capacity has received much attention in recent years. Nature has evolved different strategies for surviving dry, arid, and xeric conditions. Nature is a school for human beings. In this contribution, inspired by the Stenocara beetle, superhydrophilic/superhydrophobic patterned surfaces are fabricated on the silica poly(dimethylsiloxane) (PDMS)-coated superhydrophobic surfaces using a pulsed laser deposition approach with masks. The resultant samples with patterned wettability demonstrate water-harvesting efficiency in comparison with the silica PDMS-coated superhydrophobic surface and the Pt nanoparticles-coated superhydrophilic surface. The maximum water-harvesting efficiency can reach about 5.3 g cm -2 h -1 . Both the size and the percentage of the Pt-coated superhydrophilic square regions on the patterned surface affect the condensation and coalescence of the water droplet, as well as the final water-harvesting efficiency. The present water-harvesting strategy should provide an avenue to alleviate the water crisis facing mankind in certain arid regions of the world. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance of a piezoelectric energy harvester in actual rain

International Nuclear Information System (INIS)

Wong, Voon-Kean; Ho, Jee-Hou; Chai, Ai-Bao

2017-01-01

When raindrops impact on the surface of a piezoelectric beam, strain energy produced by the impinging raindrop will be converted to harvestable electrical energy by the piezoelectric layers in a cantilever beam. The novelty of this study is to investigate the performance of the harvester in actual rain and provide practical insights on implementation. The influences of rain parameters such as rain rate, rainfall depth, raindrop count, and drop size distribution (DSD) are discussed in this study. The raindrops accumulated on the surface of the piezoelectric beam will form a water layer. It is described using added mass coefficient in this study. In an actual rain experiment, a piezoelectric beam with surface area of 0.0018 m 2 is able to produce 2076 μJ of energy over a duration of 301 min. The energy generation of a raindrop impact piezoelectric energy harvester is highly dependent on the rain rate. Due to the inconsistency of the energy generation, the piezoelectric energy harvester would require an integration of suitable energy storage device for continuous operation. Nevertheless, this work shows the feasibility of harvesting raindrop energy using a piezoelectric beam. - Highlights: • The performance of a piezoelectric rain energy harvester is tested in actual rain. • The energy generation is highly dependent on the rain rate. • Practical insights on the implementation of the harvester are discussed. • A total energy of 2076 μJ is generated over a duration of 301 min.

The value of STIR sequence in the characterization of mediastinal lymph nodes

Directory of Open Access Journals (Sweden)

Aylin Okur

2013-12-01

Full Text Available INTRODUCTION: To investigate availability of Short Time Inversion Recovery Turbo Spin Echo Magnetic Resonance imaging (STIR TSE MRI in the detection of mediastinal lymph nodes and in the distinguishing malign and benign lymph nodes detected in cases with pulmonary lesions. METHODS: Overall, 46 patients having mediastinal lymph nodes with confirmed or suspected lung cancer were included to the study. All patients underwent STIR TSE MR imaging before mediastinoscopy. Lymph nodes were assessed by signal characteristics on STIR TSE MRI. The results of histopathological evaluation and STIR TSE MRI were compared after mediastinoscopy. As data were qualitative, distributions were expressed as percentage and chi-square test was used to determine the difference between variables. RESULTS: Overall, 92 lymph nodes were analyzed. When a comparison was made between malign and benign lymph nodes, a significant difference was found between STIR MRI signal properties of lymph nodes and lymph node size. The specificity, sensitivity, positive predictive value and negative predictive value of STIR TSE MRI were estimated as 75.0%, 75.0%, 61.5% and 83.3%, respectively. DISCUSSION AND CONCLUSION: Although the negative predictive value is high in STIR TSE MRI, it has a low positive predictive value. Thus, the case may directly undergo surgery without performing mediastinoscopy when no malign lymph node is detected in STIR TSE MRI, while mediastinoscopy is warranted when a malign lymph node is detected.

nodeGame: Real-time, synchronous, online experiments in the browser.

Science.gov (United States)

Balietti, Stefano

2017-10-01

nodeGame is a free, open-source JavaScript/ HTML5 framework for conducting synchronous experiments online and in the lab directly in the browser window. It is specifically designed to support behavioral research along three dimensions: (i) larger group sizes, (ii) real-time (but also discrete time) experiments, and (iii) batches of simultaneous experiments. nodeGame has a modular source code, and defines an API (application programming interface) through which experimenters can create new strategic environments and configure the platform. With zero-install, nodeGame can run on a great variety of devices, from desktop computers to laptops, smartphones, and tablets. The current version of the software is 3.0, and extensive documentation is available on the wiki pages at http://nodegame.org .

Study of Piezoelectric Vibration Energy Harvester with non-linear conditioning circuit using an integrated model

Science.gov (United States)

Manzoor, Ali; Rafique, Sajid; Usman Iftikhar, Muhammad; Mahmood Ul Hassan, Khalid; Nasir, Ali

2017-08-01

Piezoelectric vibration energy harvester (PVEH) consists of a cantilever bimorph with piezoelectric layers pasted on its top and bottom, which can harvest power from vibrations and feed to low power wireless sensor nodes through some power conditioning circuit. In this paper, a non-linear conditioning circuit, consisting of a full-bridge rectifier followed by a buck-boost converter, is employed to investigate the issues of electrical side of the energy harvesting system. An integrated mathematical model of complete electromechanical system has been developed. Previously, researchers have studied PVEH with sophisticated piezo-beam models but employed simplistic linear circuits, such as resistor, as electrical load. In contrast, other researchers have worked on more complex non-linear circuits but with over-simplified piezo-beam models. Such models neglect different aspects of the system which result from complex interactions of its electrical and mechanical subsystems. In this work, authors have integrated the distributed parameter-based model of piezo-beam presented in literature with a real world non-linear electrical load. Then, the developed integrated model is employed to analyse the stability of complete energy harvesting system. This work provides a more realistic and useful electromechanical model having realistic non-linear electrical load unlike the simplistic linear circuit elements employed by many researchers.

Modular sensor network node

Science.gov (United States)

Davis, Jesse Harper Zehring [Berkeley, CA; Stark, Jr., Douglas Paul; Kershaw, Christopher Patrick [Hayward, CA; Kyker, Ronald Dean [Livermore, CA

2008-06-10

A distributed wireless sensor network node is disclosed. The wireless sensor network node includes a plurality of sensor modules coupled to a system bus and configured to sense a parameter. The parameter may be an object, an event or any other parameter. The node collects data representative of the parameter. The node also includes a communication module coupled to the system bus and configured to allow the node to communicate with other nodes. The node also includes a processing module coupled to the system bus and adapted to receive the data from the sensor module and operable to analyze the data. The node also includes a power module connected to the system bus and operable to generate a regulated voltage.

New models and online calculator for predicting non-sentinel lymph node status in sentinel lymph node positive breast cancer patients

Directory of Open Access Journals (Sweden)

Johnson Denise L

2008-03-01

Full Text Available Abstract Background Current practice is to perform a completion axillary lymph node dissection (ALND for breast cancer patients with tumor-involved sentinel lymph nodes (SLNs, although fewer than half will have non-sentinel node (NSLN metastasis. Our goal was to develop new models to quantify the risk of NSLN metastasis in SLN-positive patients and to compare predictive capabilities to another widely used model. Methods We constructed three models to predict NSLN status: recursive partitioning with receiver operating characteristic curves (RP-ROC, boosted Classification and Regression Trees (CART, and multivariate logistic regression (MLR informed by CART. Data were compiled from a multicenter Northern California and Oregon database of 784 patients who prospectively underwent SLN biopsy and completion ALND. We compared the predictive abilities of our best model and the Memorial Sloan-Kettering Breast Cancer Nomogram (Nomogram in our dataset and an independent dataset from Northwestern University. Results 285 patients had positive SLNs, of which 213 had known angiolymphatic invasion status and 171 had complete pathologic data including hormone receptor status. 264 (93% patients had limited SLN disease (micrometastasis, 70%, or isolated tumor cells, 23%. 101 (35% of all SLN-positive patients had tumor-involved NSLNs. Three variables (tumor size, angiolymphatic invasion, and SLN metastasis size predicted risk in all our models. RP-ROC and boosted CART stratified patients into four risk levels. MLR informed by CART was most accurate. Using two composite predictors calculated from three variables, MLR informed by CART was more accurate than the Nomogram computed using eight predictors. In our dataset, area under ROC curve (AUC was 0.83/0.85 for MLR (n = 213/n = 171 and 0.77 for Nomogram (n = 171. When applied to an independent dataset (n = 77, AUC was 0.74 for our model and 0.62 for Nomogram. The composite predictors in our model were the product of

Energy harvesting from high-rise buildings by a piezoelectric harvester device

International Nuclear Information System (INIS)

Xie, X.D.; Wang, Q.; Wang, S.J.

2015-01-01

A novel piezoelectric technology of harvesting energy from high-rise buildings is developed. While being used to harness vibration energy of a building, the technology is also helpful to dissipate vibration of the building by the designed piezoelectric harvester as a tuned mass damper. The piezoelectric harvester device is made of two groups of series piezoelectric generators connected by a shared shaft. The shaft is driven by a linking rod hinged on a proof mass on the tip of a cantilever fixed on the roof of the building. The influences of some practical considerations, such as the mass ratio of the proof mass to the main structure, the ratios of the length and flexural rigidity of the cantilever to those of the main structure, on the root mean square (RMS) of the generated electric power and the energy harvesting efficiency of the piezoelectric harvester device are discussed. The research provides a new method for an efficient and practical energy harvesting from high-rise buildings by piezoelectric harvesters. - Highlights: • A new piezoelectric technology in energy harvesting from high-rise buildings is introduced. • A new mathematics model to calculate the energy harvested by the piezoelectric device is developed. • A novel efficient design of the piezoelectric harvester device in provided. • An electric power up to 432 MW under a seismic excitation at a frequency of 30 rad/s is achieved.

Detection of sentinel nodes with radiopharmaceuticals

International Nuclear Information System (INIS)

Yokoyama, Kunihiko; Michigishi, Takatoshi; Kinuya, Seigo; Konishi, Shota; Nakajima, Kenichi; Tonami, Norihisa

2000-01-01

Sentinel lymph nodes have been found to be an indicator of lymph node metastasis in breast cancer. In Japan, the theory and concept of sentinel lymph nodes in breast cancer have begun to be applied to carcinomas of the digestive system. Based on clinical experience in the detection of sentinel lymph nodes with radiopharmaceuticals, differences and similarities between the radiopharmaceuticals, methods, and techniques used to detect sentinel lymph nodes have been assessed in relation to breast cancer and carcinomas of the digestive system (including carcinomas of the esophagus and large intestine). The greatest difference between the methods used for breast and digestive cancers is the site of administration of the radiopharmaceutical. In breast cancer, the radiopharmaceutical is administered into a superficial organ (i.e., the mammary gland), whereas in carcinomas of the digestive system, it is administered into a deep organ (i.e., digestive tract). Another obvious difference is in lymph flow, i.e., the flow of the mammary glands is subcutaneous whereas lymph flow in the digestive tract is submucosal. Two radionuclide diagnostic methods are available to detect sentinel lymph nodes: sentinel lymphoscintigraphy with a gamma camera and a method that involves the use of a gamma probe intraoperatively. Radiopharmaceuticals used to detect sentinel lymph nodes must be smoothly transferred from the site of administration into the lymph, and uptake by the sentinel lymph node must continue for a long time without excessive flowing to lower reaches. The optimal particle size remains a matter of controversy, and no radiopharmaceuticals appropriate for lymphoscintigraphy have ever been approved in Japan. The authors compared the pharmacokinetics of three different radiopharmaceuticals used for sentinel lymphoscintigraphy in breast cancer ( 99m Tc-labeled albumin, 99m Tc-labeled tin colloid, and 99m Tc-labeled phytic acid) and founded that the detection rate was lowest with

Do tumor size or patient age influence the accuracy of sentinel lymph node (Sn) detection in breast cancer?

International Nuclear Information System (INIS)

Cortes, M.; Fernandez, A.; Benito, E.; Azpeitia, D.; Ricart, Y.; Escobedo, A.; Martin-Comin, J.

2002-01-01

Full text: The aim was to analyze the influence of the age of the patient and tumor size on the accuracy to identify SN in patients with breast cancer. The whole population are 250 patients with breast cancer. In 236 data on size and age were available. Mean age was 53.6 years, range 28-87 years. Patients were classified 1) depending an age: 40 60 years: 73 p and 2) depending on tumor size (mm): 30: 46 p. Examination protocol: All patients received a peritumoral injection of 111 MBq (3mCi) of 99mTc-HSA-nanocolloid in 1 - 3 ml. 2 h later 300 seconds anterior and lateral thoracic scans were obtained. A 57-Co flood phantom was positioned back to the patient to outline the anatomical contour and help to localize SN. SN was marked on the skin with permanent ink. Intraoperative SN localization was performed using a gamma probe. Histopathologic analysis of SN was done with haematoxylin/eosin, immunohistochemistry and PCR. Histopathology of the SN was compared to the histopathology of all the other lymph nodes drawn out by the surgeon. SN were identified by lymphoscintigraphy in 227 cases of 250 (91 %). 221 of them (97 %) were localized in axyla. In 210 of 221 SN could be localized and drawn out at surgery. The no detection and false negative rate were much higher in patients aged > 60 (29 and 33 %) and in tumors > 30 mm (32 and 19 %) than in patients 60 y and tumors > 30 mm (46 %) and the highest false negative rate appears in patients >60 and tumors > 30 mm (33 %) 1) No FN were found in patients with tumor size <10 mm. 2) No FN were found in patients aged under 40 years. 3) FN rate seems to be higher in older patients. 4) The age of patients and the size of tumor seem to influence an the SN detection rates. (author)

BROADBAND CONCEPT OF ENERGY HARVESTING IN BEAM VIBRATING SYSTEMS FOR POWERING SENSORS

Directory of Open Access Journals (Sweden)

Andrzej Rysak

2014-09-01

Full Text Available Recent demand for powering small sensors for wireless health monitoring triggered activities in the field of small size efficient energy harvesting devices. We examine energy harvesting in an aluminium beam with a piezoceramic patch subjected to kinematic harmonic excitation and impacts. Due to a mechanical stopper applied, inducing a hardening effect in the spring characteristic of the beam resonator, we observed a broader frequency range for the fairly large power output. Impact nonlinearities caused sensitivity to initial conditions and appearance of multiple solutions. The occurrence of resonant solution associated with impacts increased efficiency of the energy harvesting process.

[Application of Da Vinci surgical robot in the dissection of splenic hilar lymph nodes for gastric cancer patients with total gastrectomy].

Science.gov (United States)

Yang, Kun; Chen, Xinzu; Zhang, Weihan; Chen, Xiaolong; Hu, Jiankun

2016-08-25

To investigate the feasibility and safety of Da Vinci surgical robot in the dissection of splenic hilar lymph nodes for gastric cancer patients with total gastrectomy. Clinical data of two cases who underwent total gastrectomy for cardia cancer at our department in January 2016 were analyzed retrospectively. Two male patients were 62 and 55 years old respectively, with preoperative diagnosis as cT2-3N0M0 and cT1-2N0M0 gastric cancer by gastroscope and biopsy, and both received robotic total gastrectomy spleen-preserving splenic hilar lymph node dissection successfully. The operative time for splenic hilar lymph node dissection was 30 min and 25 min respectively. The intraoperative estimated blood loss was both 100 ml, while the number of total harvested lymph node was 38 and 33 respectively. One dissected splenic hilar lymph node and fatty tissues in two patients were proven by pathological examinations. There were no anastomotic leakage, pancreatic fistula, splenic infarction, intraluminal bleeding, digestive tract bleeding, aneurysm of splenic artery, and other operation-associated complications. Both patients suffered from postoperative pneumonia, and were cured by conservative therapy. The robotic spleen-preserving splenic hilar lymph node dissection is feasible and safe, but its superiority needs further evaluation.

Skin invasion and prognosis in node negative breast cancer: a retrospective study

Directory of Open Access Journals (Sweden)

Horii Rie

2008-01-01

Full Text Available Abstract Background The impact of skin invasion in node negative breast cancer is uncertain. Methods We determined the prognosis in 97 node negative breast cancer patients (case group who had tumors with skin invasion. Then we compared these patients with 4500 node negative invasive breast cancer patients treated surgically in the same period. Results Patients with skin invasion tended to be older, had more invasive lobular carcinoma and larger tumor size, and were less likely to have breast conserving surgery than those in the control group. The 5-year disease-free survival rate in the case group was 94.0%. There was no significant difference in the 10-year disease-specific overall survival rates in terms of skin invasion in node negative patients (90.7% in the case group, 92.9% in the control group; p = 0.2032. Conclusion Results suggest that skin invasion has no impact on survival in node negative invasive breast cancer patients. The adjuvant regimens which the individual institute applies for node negative breast cancer should be used regardless of skin invasion.

Sentinel Node Biopsy Alone versus Completion Axillary Node Dissection in Node Positive Breast Cancer: Systematic Review and Meta-Analysis

Directory of Open Access Journals (Sweden)

Rachna Ram

2014-01-01

Full Text Available Introduction. There has been recent interest in validity of completion axillary node dissection after a positive sentinel node. This systematic review aims to ascertain if sentinel lymph node dissection alone was noninferior to axillary lymph node dissection for breast cancer patients who have a positive sentinel node. Method. A systematic review of the electronic databases Embase, MEDLINE, and Cochrane Register of Controlled Trials was carried out. Only randomised trials that had patients with positive sentinel node as the study sample were included in the meta-analysis using the reported hazard ratios with a fixed effect model. Results. Three randomised controlled trials and five retrospective studies were identified. The pooled effect for overall survival was HR 0.94, 95% CI [0.79, 1.19], and for disease free survival was HR 0.83, 95% CI [0.60, 1.14]. The reported rates for locoregional recurrence were similar in both groups. The surgical morbidity was found to be significantly more in patients who had underwent axillary dissection. Conclusion. Amongst patients with micrometastasis in the sentinel node, no further axillary dissection is necessary. For patients with macrometastasis in the sentinel node, it is reasonable to consider omitting axillary dissection to avoid the morbidity of the procedure.

Gadolinium-DTPA enhancement of regional lymph nodes of lung cancer in magnetic resonance imaging

International Nuclear Information System (INIS)

Iwai, Naomichi; Yamaguchi, Yutaka

1991-01-01

Enhanced MR imagings were performed on thirty-one patients with lung cancer by intravenous administration of 0.1 mmol/kg Gadolinium-DTPA (Gd-DTPA). A spin-echo pulse sequence (SE 400/40) with 0.5-T MR system was used. The Gd-DTPA enhancement of lymph nodes was studied for 67 nodes (29 metastatic lymph nodes and 38 non-metastatic lymph nodes) on the hilar and mediastinal region. The mean signal intensity of metastatic lymph nodes was enhanced higher than that of non-metastatic lymph nodes (p<0.001). On the criterion of the signal intensity change (the cutoff point: 800 S.I) at 5 minutes after administration, the diagnostic rates on retrospective study showed a sensitivity of 79 %, a specificity of 84 % and an overall accuracy of 82%. These data show higher rates than those of the size criteria. This study suggests a significant potential for improved detection of lymph node metastasis of lung cancer with Gd-DTPA enhanced MR imaging. (author)

Study on Drive System of Hybrid Tree Harvester

Directory of Open Access Journals (Sweden)

Shen Rong-feng

2017-01-01

Full Text Available Hybrid tree harvester with a 60 kW diesel engine combined with a battery pile could be a “green” forest harvesting and transportation system. With the new design, the diesel engine maintains a constant engine speed, keeping fuel consumption low while charging the batteries that drive the forwarder. As an additional energy saving method, the electric motors work as generators to charge the battery pile when the vehicle moves downhill. The vehicle is equipped with six large wheels providing high clearance over uneven terrain while reducing ground pressure. Each wheel is driven via a hub gear by its own alternating current motor, and each of the three wheel pairs can be steered independently. The combination of the diesel engine and six electric motors provides plenty of power for heavy lifting and pulling. The main component parameters of the drive system are calculated and optimized with a set of dynamics and simulated with AVL Cruise software. The results provide practical insights for the fuel tree harvester and are helpful to reduce the structure and size of the tree harvester. Advantage Environment provides information about existing and future products designed to reduce environmental impacts.

Nonlinear metamaterials for electromagnetic energy harvesting (Conference Presentation)

Science.gov (United States)

Oumbe Tekam, Gabin Thibaut; Ginis, Vincent; Seetharamdoo, Divitha; Danckaert, Jan

2016-09-01

Surrounded by electromagnetic radiation coming from wireless power transfer to consumer devices such as mobile phones, computers and television, our society is facing the scientific and technological challenge to recover energy that is otherwise lost to the environment. Energy harvesting is an emerging field of research focused on this largely unsolved problem, especially in the microwave regime. Metamaterials provide a very promising platform to meet this purpose. These artificial materials are made from subwavelength building blocks, and can be designed by resonate at particular frequencies, depending on their shape, geometry, size, and orientation. In this work, we show that an efficient electromagnetic energy harvester can be design by inserting a nonlinear element directly within the metamaterial unit cell, leading to the conversion of RF input power to DC charge accumulation. The electromagnetic energy harvester operating at microwave frequencies is built from a cut-wire metasurface, which operates as a quasistatic electric dipole resonator. Using the equivalent electrical circuit, we design the parameters to tune the resonance frequency of the harvester at the desired frequency, and we compare these results with numerical simulations. Finally, we discuss the efficiency of our metamaterial energy harvesters. This work potentially offers a variety of applications, for example in the telecommunications industry to charge phones, in robotics to power microrobots, and also in medicine to advance pacemakers or health monitoring sensors.

Controlling data transfers from an origin compute node to a target compute node

Science.gov (United States)

Archer, Charles J [Rochester, MN; Blocksome, Michael A [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian E [Rochester, MN

2011-06-21

Methods, apparatus, and products are disclosed for controlling data transfers from an origin compute node to a target compute node that include: receiving, by an application messaging module on the target compute node, an indication of a data transfer from an origin compute node to the target compute node; and administering, by the application messaging module on the target compute node, the data transfer using one or more messaging primitives of a system messaging module in dependence upon the indication.

MEMS fabricated energy harvesting device with 2D resonant structure

DEFF Research Database (Denmark)

Crovetto, Andrea; Wang, Fei; Triches, Marco

This paper reports on a MEMS energy harvester able to generate power from two perpendicular ambient vibration directions. CYTOP polymer is used both as the electret material for electrostatic transduction and as a bonding interface for low-temperature wafer bonding. With final chip size of ~1 cm2......, an output power of 32.5 nW is reached with an external load of 17 MΩ, under a harmonic source motion with acceleration RMS amplitude 0.03 g (0.3 m/s2) and frequency 179 Hz.......This paper reports on a MEMS energy harvester able to generate power from two perpendicular ambient vibration directions. CYTOP polymer is used both as the electret material for electrostatic transduction and as a bonding interface for low-temperature wafer bonding. With final chip size of ~1 cm2...

Analytical coupled modeling of a magneto-based acoustic metamaterial harvester

Science.gov (United States)

Nguyen, H.; Zhu, R.; Chen, J. K.; Tracy, S. L.; Huang, G. L.

2018-05-01

Membrane-type acoustic metamaterials (MAMs) have demonstrated unusual capacity in controlling low-frequency sound transmission, reflection, and absorption. In this paper, an analytical vibro-acoustic-electromagnetic coupling model is developed to study MAM harvester sound absorption, energy conversion, and energy harvesting behavior under a normal sound incidence. The MAM harvester is composed of a prestressed membrane with an attached rigid mass, a magnet coil, and a permanent magnet coin. To accurately capture finite-dimension rigid mass effects on the membrane deformation under the variable magnet force, a theoretical model based on the deviating acoustic surface Green’s function approach is developed by considering the acoustic near field and distributed effective shear force along the interfacial boundary between the mass and the membrane. The accuracy and capability of the theoretical model is verified through comparison with the finite element method. In particular, sound absorption, acoustic-electric energy conversion, and harvesting coefficient are quantitatively investigated by varying the weight and size of the attached mass, prestress and thickness of the membrane. It is found that the highest achievable conversion and harvesting coefficients can reach up to 48%, and 36%, respectively. The developed model can serve as an efficient tool for designing MAM harvesters.

LCP nanoparticle for tumor and lymph node metastasis imaging

Science.gov (United States)

Tseng, Yu-Cheng

A lipid/calcium/phosphate (LCP) nanoparticle formulation (particle diameter ˜25 nm) has previously been developed to delivery siRNA with superior efficiency. In this work, 111In was formulated into LCP nanoparticles to form 111In-LCP for SPECT/CT imaging. With necessary modifications and improvements of the LCP core-washing and surface-coating methods, 111In-LCP grafted with polyethylene glycol exhibited reduced uptake by the mononuclear phagocytic system. SPECT/CT imaging supported performed biodistribution studies, showing clear tumor images with accumulation of 8% or higher injected dose per gram tissue (ID/g) in subcutaneous, human-H460, lung-cancer xenograft and mouse-4T1, breast cancer metastasis models. Both the liver and the spleen accumulated ˜20% ID/g. Accumulation in the tumor was limited by the enhanced permeation and retention effect and was independent of the presence of a targeting ligand. A surprisingly high accumulation in the lymph nodes (˜70% ID/g) was observed. In the 4T1 lymph node metastasis model, the capability of intravenously injected 111In-LCP to visualize the size-enlarged and tumor-loaded sentinel lymph node was demonstrated. By analyzing the SPECT/CT images taken at different time points, the PK profiles of 111In-LCP in the blood and major organs were determined. The results indicated that the decrement of 111In-LCP blood concentration was not due to excretion, but to tissue penetration, leading to lymphatic accumulation. Larger LCP (diameter ˜65 nm) nanoparticles were also prepared for the purpose of comparison. Results indicated that larger LCP achieved slightly lower accumulation in the tumor and lymph nodes, but much higher accumulation in the liver and spleen; thus, larger nanoparticles might not be favorable for imaging purposes. We also demonstrated that LCP with a diameter of ˜25 nm were better able to penetrate into tissues, travel in the lymphatic system and preferentially accumulate in the lymph nodes due to 1) small

Protocol for multiple node network

Science.gov (United States)

Kirkham, Harold (Inventor)

1995-01-01

The invention is a multiple interconnected network of intelligent message-repeating remote nodes which employs an antibody recognition message termination process performed by all remote nodes and a remote node polling process performed by other nodes which are master units controlling remote nodes in respective zones of the network assigned to respective master nodes. Each remote node repeats only those messages originated in the local zone, to provide isolation among the master nodes.

Sentinel node biopsy before neoadjuvant chemotherapy spares breast cancer patients axillary lymph node dissection.

Science.gov (United States)

van Rijk, Maartje C; Nieweg, Omgo E; Rutgers, Emiel J T; Oldenburg, Hester S A; Olmos, Renato Valdés; Hoefnagel, Cornelis A; Kroon, Bin B R

2006-04-01

Neoadjuvant chemotherapy in breast cancer patients is a valuable method to determine the efficacy of chemotherapy and potentially downsize the primary tumor, which facilitates breast-conserving therapy. In 18 studies published about sentinel node biopsy after neoadjuvant chemotherapy, the sentinel node was identified in on average 89%, and the false-negative rate was on average 10%. Because of these mediocre results, no author dares to omit axillary clearance just yet. In our institute, sentinel lymph node biopsy is performed before neoadjuvant chemotherapy. The aim of this study was to evaluate our experience with this approach. Sentinel node biopsy was performed before neoadjuvant chemotherapy in 25 T2N0 patients by using lymphoscintigraphy, a gamma ray detection probe, and patent blue dye. Axillary lymph node dissection was performed after chemotherapy if the sentinel node contained metastases. Ten patients had a tumor-positive axillary sentinel node, and one patient had an involved lateral intramammary node. Four patients had additional involved nodes in the completion lymph node dissection specimen. The other 14 patients (56%) had a tumor-negative sentinel node and did not undergo axillary lymph node dissection. No recurrences have been observed after a median follow-up of 18 months. Fourteen (56%) of the 25 patients were spared axillary lymph node dissection when the sentinel node was found to be disease free. Performing sentinel node biopsy before neoadjuvant chemotherapy seems successful and reliable in patients with T2N0 breast cancer.

Selecting novel material of vegetable pea for mechanical harvesting and canning

Directory of Open Access Journals (Sweden)

Kaigorodova Irina M.

2016-01-01

Full Text Available Breeding of novel pea cultivars is of significant interest in scope of increasing food shortages. The cultivars of new generation have to be highly technological and appropriate for mechanical treatment in all stages of planting. To provide higher outcome of plant products, pea is to be harvested for prolonged seasonal period, i.e. bred for conveyor usage. In this paper we presented the results of preliminary investigation of pea germplasm collection and studies on inheritance of flowering time in a series of crosses. We evaluated all hybrid progeny for duration of vegetation, lodging resistance and seed mass. Seven maturity groups were emphasized with most of obtained lines exhibiting an average duration of vegetation period measured as number of sterile nodes (11-15 for average fraction. As a result of this survey, the prospective genotypes for breeding new forms resistant to lodging and suitable for mechanical harvest were isolated. We propose a scheme of conveyor usage of new forms for sustainable delivery of stock for conversion industry. The obtained material is recommended for further improvement as the initial material for breeding.

CMOS circuits for piezoelectric energy harvesters efficient power extraction, interface modeling and loss analysis

CERN Document Server

Hehn, Thorsten

2014-01-01

This book deals with the challenge of exploiting ambient vibrational energy which can be used to power small and low-power electronic devices, e.g. wireless sensor nodes. Generally, particularly for low voltage amplitudes, low-loss rectification is required to achieve high conversion efficiency. In the special case of piezoelectric energy harvesting, pulsed charge extraction has the potential to extract more power compared to a single rectifier. For this purpose, a fully autonomous CMOS integrated interface circuit for piezoelectric generators which fulfills these requirements is presented.Due

An expert system for estimating production rates and costs for hardwood group-selection harvests

Science.gov (United States)

Chris B. LeDoux; B. Gopalakrishnan; R. S. Pabba

2003-01-01

As forest managers shift their focus from stands to entire ecosystems alternative harvesting methods such as group selection are being used increasingly. Results of several field time and motion studies and simulation runs were incorporated into an expert system for estimating production rates and costs associated with harvests of group-selection units of various size...

Clinicopathologic Predictive Factors of Cervical Lymph Node Metastasis in Differentiated Thyroid Cancer.

Science.gov (United States)

Sun, Ronghao; Zhang, Hua; Liu, Kun; Fan, Jinchuan; Li, Guojun; Song, Xicheng; Li, Chao

Cervical lymph node metastasis (LNM) has been proven to be a predictor for locoregional recurrence in differentiated thyroid carcinoma (DTC). Clinicopathological features could be effective predictive factors for central and lateral LNM of DTC, and provide references to surgeons for cervical neck dissection. Retrospective analysis of clinicopathological data was performed on 420 patients who underwent initial surgery from 2010 to 2015. The incidence of central and lateral LNM was calculated. Of 420 patients, 247 (58.8%) exhibited central LNM, and 185 (44.1%) exhibited lateral LNM. There were 29 (6.9%) cases confirmed to have skip metastasis. Univariate and multivariate analysis revealed that tumour location, tumour size, multifocality, capsular invasion, affected lobes, and age were independent predictors of central LNM. Tumour location, capsular invasion, affected lobes, and tumour size were independent predictors of lateral LNM. Our findings suggest that tumour location, affected lobes, capsular invasion, age, tumour size and multifocality may be taken as predictive factors for cervical LNM of DTC. Meticulous perioperative evaluation of cervical LNM and prophylactic cervical lymph node dissection that aims to remove the occult lymph nodes may be an option for DTC with risk factors. Copyright © 2017. Publicado por Elsevier España, S.L.U.

Detection of sentinel lymph node in breast cancer and malignant melanoma - Influence of some factors on detection success rate

International Nuclear Information System (INIS)

Krafta, O.; Safarcika, K.; Stepien, A.

2004-01-01

Full text: The aim of this study was to compare three radiopharmaceuticals for sentinel lymph node detection in breast cancer and malignant melanoma patients. We examined 100 women and 2 men with breast cancer (average age 59.3 years) and 167 patients with malignant melanoma (69 men with mean age of 58.6 years and 98 women with mean age of 53.6 years). Lymphoscintigraphy was performed in all patients after injection of the radiotracer, either of the three: NANOCIS (average particle size 100 nm), SENTISCINT (particle size 100-600 nm), and NANOCOLL (particle size under 80 nm). Dynamic scintigraphy was performed in melanoma patients while breast cancer patients were subjected to stating imaging at 1-2 and 22 hours of injection. In patients with melanoma surgery was done on the same day, to remove the primary tumor, sentinel lymph node and other nodes, wherever required. In breast cancer patients, surgery, more or less, was done on the second day of radiotracer injection. In operation theatre isosulfan blue dye and gamma probe was used to detect sentinel lymph nodes. In breast cancer patients, scintigraphy detected a total of 231 lymph nodes but failed to show sentinel lymph node in 7 patients (success rate of lymphoscintigraphy 93.1 %). Using gamma probe 158 lymph nodes were detected in 89 patients but sentinel nodes were missed in 9 patients (success rate of probe was 89.9 %). 146 lymph nodes could be visualised using blue dye in 92 patients but were missed in 12 patients (detection rate by dye was 87 %). In 2 patients sentinel lymph node could not be detected by any method. In patients with melanoma, scintigraphy showed 304 lymph nodes. However, it did not detect sentinel lymph node in 9 patients (success rate of lymphoscintigraphy was 94.6 %). 104 patients were examined by means of gamma probe and 132 lymph nodes were detected and no lymph node was found in 13 patients (success rate of probe 87.5%). Using blue dye in 140 patients, 131 nodes were found but were

Managing harvest and habitat as integrated components

Science.gov (United States)

Osnas, Erik; Runge, Michael C.; Mattsson, Brady J.; Austin, Jane E.; Boomer, G. S.; Clark, R. G.; Devers, P.; Eadie, J. M.; Lonsdorf, E. V.; Tavernia, Brian G.

2014-01-01

In 2007, several important initiatives in the North American waterfowl management community called for an integrated approach to habitat and harvest management. The essence of the call for integration is that harvest and habitat management affect the same resources, yet exist as separate endeavours with very different regulatory contexts. A common modelling framework could help these management streams to better understand their mutual effects. Particularly, how does successful habitat management increase harvest potential? Also, how do regional habitat programmes and large-scale harvest strategies affect continental population sizes (a metric used to express habitat goals)? In the ensuing five years, several projects took on different aspects of these challenges. While all of these projects are still on-going, and are not yet sufficiently developed to produce guidance for management decisions, they have been influential in expanding the dialogue and producing some important emerging lessons. The first lesson has been that one of the more difficult aspects of integration is not the integration across decision contexts, but the integration across spatial and temporal scales. Habitat management occurs at local and regional scales. Harvest management decisions are made at a continental scale. How do these actions, taken at different scales, combine to influence waterfowl population dynamics at all scales? The second lesson has been that consideration of the interface of habitat and harvest management can generate important insights into the objectives underlying the decision context. Often the objectives are very complex and trade-off against one another. The third lesson follows from the second – if an understanding of the fundamental objectives is paramount, there is no escaping the need for a better understanding of human dimensions, specifically the desires of hunters and nonhunters and the role they play in conservation. In the end, the compelling question is

Factors influencing reporting and harvest probabilities in North American geese

Science.gov (United States)

Zimmerman, G.S.; Moser, T.J.; Kendall, W.L.; Doherty, P.F.; White, Gary C.; Caswell, D.F.

2009-01-01

We assessed variation in reporting probabilities of standard bands among species, populations, harvest locations, and size classes of North American geese to enable estimation of unbiased harvest probabilities. We included reward (US10,20,30,50, or100) and control (0) banded geese from 16 recognized goose populations of 4 species: Canada (Branta canadensis), cackling (B. hutchinsii), Ross's (Chen rossii), and snow geese (C. caerulescens). We incorporated spatially explicit direct recoveries and live recaptures into a multinomial model to estimate reporting, harvest, and band-retention probabilities. We compared various models for estimating harvest probabilities at country (United States vs. Canada), flyway (5 administrative regions), and harvest area (i.e., flyways divided into northern and southern sections) scales. Mean reporting probability of standard bands was 0.73 (95 CI 0.690.77). Point estimates of reporting probabilities for goose populations or spatial units varied from 0.52 to 0.93, but confidence intervals for individual estimates overlapped and model selection indicated that models with species, population, or spatial effects were less parsimonious than those without these effects. Our estimates were similar to recently reported estimates for mallards (Anas platyrhynchos). We provide current harvest probability estimates for these populations using our direct measures of reporting probability, improving the accuracy of previous estimates obtained from recovery probabilities alone. Goose managers and researchers throughout North America can use our reporting probabilities to correct recovery probabilities estimated from standard banding operations for deriving spatially explicit harvest probabilities.

Energy harvesting from mastication forces via a smart tooth

Science.gov (United States)

Bani-Hani, Muath; Karami, M. Amin

2016-04-01

The batteries of the current pacing devices are relatively large and occupy over 60 percent of the size of pulse generators. Therefore, they cannot be placed in the subtle areas of human body. In this paper, the mastication force and the resulting tooth pressure are converted to electricity. The pressure energy can be converted to electricity by using the piezoelectric effect. The tooth crown is used as a power autonomous pulse generator. We refer to this envisioned pulse generator as the smart tooth. The smart tooth is in the form of a dental implant. A piezoelectric vibration energy harvester is designed and modeled for this purpose. The Piezoelectric based energy harvesters investigated and analyzed in this paper initially includes a single degree of freedom piezoelectric based stack energy harvester which utilizes a harvesting circuit employing the case of a purely resistive circuit. The next step is utilizing and investigating a bimorph piezoelectric beam which is integrated/embedded in the smart tooth implant. Mastication process causes the bimorph beam to buckle or return to unbuckled condition. The transitions results in vibration of the piezoelectric beam and thus generate energy. The power estimated by the two mechanisms is in the order of hundreds of microwatts. Both scenarios of the energy harvesters are analytically modeled. The exact analytical solution of the piezoelectric beam energy harvester with Euler-Bernoulli beam assumptions is presented. The electro-mechanical coupling and the geometric nonlinearities have been included in the model for the piezoelectric beam.

Population Modeling Approach to Optimize Crop Harvest Strategy. The Case of Field Tomato.

Science.gov (United States)

Tran, Dinh T; Hertog, Maarten L A T M; Tran, Thi L H; Quyen, Nguyen T; Van de Poel, Bram; Mata, Clara I; Nicolaï, Bart M

2017-01-01

In this study, the aim is to develop a population model based approach to optimize fruit harvesting strategies with regard to fruit quality and its derived economic value. This approach was applied to the case of tomato fruit harvesting under Vietnamese conditions. Fruit growth and development of tomato (cv. "Savior") was monitored in terms of fruit size and color during both the Vietnamese winter and summer growing seasons. A kinetic tomato fruit growth model was applied to quantify biological fruit-to-fruit variation in terms of their physiological maturation. This model was successfully calibrated. Finally, the model was extended to translate the fruit-to-fruit variation at harvest into the economic value of the harvested crop. It can be concluded that a model based approach to the optimization of harvest date and harvest frequency with regard to economic value of the crop as such is feasible. This approach allows growers to optimize their harvesting strategy by harvesting the crop at more uniform maturity stages meeting the stringent retail demands for homogeneous high quality product. The total farm profit would still depend on the impact a change in harvesting strategy might have on related expenditures. This model based harvest optimisation approach can be easily transferred to other fruit and vegetable crops improving homogeneity of the postharvest product streams.

LYMPHOCYTIC THYROIDITIS IS ASSOCIATED WITH INCREASED NUMBER OF BENIGN CERVICAL NODES AND FEWER CENTRAL NECK COMPARTMENT METASTATIC LYMPH NODES IN PATIENTS WITH DIFFERENTIATED THYROID CANCER.

Science.gov (United States)

Donangelo, Ines; Walts, Ann E; Bresee, Catherine; Braunstein, Glenn D

2016-10-01

Whether or not autoimmune thyroid disease influences the progression of differentiated thyroid cancer (DTC) remains controversial. Findings of previous studies are influenced by lead time bias and/or procedure bias selection. These biases can be reduced by studying a single-institution patient population that underwent a similar extent of surgical resection. From a cohort of 660 patients with DTC who underwent thyroidectomy, we retrospectively studied 357 patients who underwent total thyroidectomy and central compartment node dissection (CCND) for DTC between 2003 and 2013. Forty-one percent (140/345) of study patients had lymphocytic thyroiditis (LT), and 30% (91/301) had serum positive for thyroglobulin antibody (TgAb). LT was reported in 78% of the TgAb-positive cases. Sixty percent (213/357) of cases had metastatic thyroid carcinoma in 1 or more neck lymph nodes (55% [198/357] central compartment, and 22% [77/356] lateral compartment). Patients with LT had fewer metastatic cervical lymph nodes than those with no LT (2.7 ± 4.7 vs 3.5 ± 4.8, respectively, P = .0285). Patients with positive TgAb and thyroiditis had a larger number of benign cervical lymph nodes removed than those with negative TgAb or no LT. No significant difference was observed in age, tumor size, multifocality, extrathyroidal extension, vascular invasion, or frequency of cervical lymph node metastasis between TgAb-negative and -positive cases or between cases with and without LT. Lymphocytic thyroiditis is associated with fewer central neck compartment metastatic lymph nodes and a larger number of excised reactive benign cervical lymph nodes. Whether this association indicates a protective role of thyroid autoimmunity in lymph node spreading remains unclear. CCND = central compartment node dissection DTC = differentiated thyroid cancer HT = Hashimoto thyroiditis LT = lymphocytic thyroiditis TgAb = thyroglobulin antibody TPO = thyroid peroxidase.

Post-harvest physiology

Science.gov (United States)

Weather and management constraints, as well as the intended use of the harvested forage, all influence the forage harvest system selected by the producer. Generally, maximum retention of dry matter from harvested forage crops is achieved at moistures intermediate between the standing fresh crop and ...

Pattern of Colon Cancer Lymph Node Metastases in Patients Undergoing Central Mesocolic Lymph Node Excision

DEFF Research Database (Denmark)

Bertelsen, Claus A; Kirkegaard-Klitbo, Anders; Nielsen, Mingyuan

2016-01-01

BACKGROUND: Extended mesocolic lymph node dissection in colon cancer surgery seems to improve oncological outcome. A possible reason might be related to metastases in the central mesocolic lymph nodes. OBJECTIVE: The purpose of this study was to describe the pattern of mesocolic lymph node...... metastases, particularly in central lymph nodes, and the risk of skip, aberrant, and gastrocolic ligament metastases as the argument for performing extended lymph node dissection. DATA SOURCES: EMBASE and PubMed were searched using the terms colon or colorectal with sentinel node, lymph node mapping, or skip...... node; lymph node resection colon; and complete or total and mesocolic excision. STUDY SELECTION: Studies describing the risk of metastases in central, skip, aberrant, and gastrocolic ligament lymph node metastases from colon adenocarcinomas in 10 or more patients were included. No languages were...

Network neighborhood analysis with the multi-node topological overlap measure.

Science.gov (United States)

Li, Ai; Horvath, Steve

2007-01-15

The goal of neighborhood analysis is to find a set of genes (the neighborhood) that is similar to an initial 'seed' set of genes. Neighborhood analysis methods for network data are important in systems biology. If individual network connections are susceptible to noise, it can be advantageous to define neighborhoods on the basis of a robust interconnectedness measure, e.g. the topological overlap measure. Since the use of multiple nodes in the seed set may lead to more informative neighborhoods, it can be advantageous to define multi-node similarity measures. The pairwise topological overlap measure is generalized to multiple network nodes and subsequently used in a recursive neighborhood construction method. A local permutation scheme is used to determine the neighborhood size. Using four network applications and a simulated example, we provide empirical evidence that the resulting neighborhoods are biologically meaningful, e.g. we use neighborhood analysis to identify brain cancer related genes. An executable Windows program and tutorial for multi-node topological overlap measure (MTOM) based analysis can be downloaded from the webpage (http://www.genetics.ucla.edu/labs/horvath/MTOM/).

Effects of Harvesting Systems and Bole Moisture Loss on Weight Scaling of Douglas-Fir Sawlogs (Pseudotsuga Menziesii var. glauca Franco

Directory of Open Access Journals (Sweden)

Jarred D. Saralecos

2014-09-01

Full Text Available Characterizing the moisture loss from felled trees is essential for determining weight-to-volume (W-V relationships in softwood sawlogs. Several factors affect moisture loss, but research to quantify the effects of bole size and harvest method is limited. This study was designed to test whether bole size, harvest method, environmental factors, and the associated changes in stem moisture content of felled Douglas-fir (Pseudotsuga menziesii var. glauca Franco affected the weight-to-volume relationship of sawlogs. Thirty trees in three size classes (12.7–25.4 cm, 25.5–38.1 cm, 38.2–50.8 cm were felled and treated with one of two harvesting processing methods. Moisture content was sampled every two days for four weeks. Results showed 6% greater moisture loss in the crowns of stems that retained limbs after felling compared to stems with limbs removed after harvesting. Additionally, moisture loss rate increased as stem size decreased. The smallest size class lost 58% moisture content compared to 34% in the largest size class throughout the study duration. These stem moisture content changes showed a 17% reduction in average sawlog weight within the largest size class, shifting current W-V relationships from 2.33 tons m−3 to 1.94 tons m−3 during the third seasonal quarter for northern Idaho Douglas-fir and potentially altering relationships year-round.

Partial axillary lymph node dissection inferior to the intercostobrachial nerves complements sentinel node biopsy in patients with clinically node-negative breast cancer.

Science.gov (United States)

Li, Jianyi; Jia, Shi; Zhang, Wenhai; Qiu, Fang; Zhang, Yang; Gu, Xi; Xue, Jinqi

2015-06-30

The practice of breast cancer diagnosis and treatment in China varies to that in western developed countries. With the unavailability of radioactive tracer technique for sentinel lymph nodes biopsy (SLNB), using blue dye alone has been the only option in China. Also, the diagnosis of breast malignant tumor in most Chinese centres heavily relies on intraoperative instant frozen histology which is normally followed by sentinel lymph nodes mapping, SLNB and the potential breast and axillary operations in one consecutive session. This practice appears to cause a high false negative rate (FNR) for SLNB. The present study aimed to investigate the impact of the current practice in China on the accuracy of SLNB, and whether partial axillary lymph node dissection (PALND), dissection of lymph nodes inferior to the intercostobrachial nerve (ICBN), was a good complementary procedure following SLNB using blue dye. 289 patients with clinically node-negative breast cancer were identified and recruited. Tumorectomy, intraoperative instant frozen histological diagnosis, SLNB using methylene blue dye, and PALND or complete axillary node dissection (ALND) were performed in one consecutive operative session. The choice of SLNB only, SLNB followed by PALND or by ALND was based on the pre-determined protocol and preoperative choice by the patient. Clinical parameters were analyzed and survival analysis was performed. 37% patients with clinically negative nodes were found nodes positive. 59 patients with positive SLN underwent ALND, including 47 patients with up to two positive nodes which were all located inferior to the ICBN. 9 patients had failed SLNB and underwent PALND. Among them, 3 (33.3%) patients were found to have one metastatic node. 149 patients showed negative SLNB but chose PALND. Among them, 30 (20.1%), 14 (9.4) and 1 (0.7%) patients were found to have one, two and three metastatic node(s), respectively. PALND detected 48 (30.4%) patients who had either failed SLNB or

Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

International Nuclear Information System (INIS)

Matova, S P; Elfrink, R; Vullers, R J M; Van Schaijk, R

2011-01-01

In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adjustable resonance frequencies have been designed—one with a solid bottom and one with membrane on the bottom. The resonance frequencies of the resonators were matched to the complementing piezoelectric harvesters during harvesting. The aim of the presented work is a feasibility study on using packaged piezoelectric energy harvesters with Helmholtz resonators for airflow energy harvesting. The maximum energy we were able to obtain was 42.2 µW at 20 m s −1

Automated Construction of Node Software Using Attributes in a Ubiquitous Sensor Network Environment

Science.gov (United States)

Lee, Woojin; Kim, Juil; Kang, JangMook

2010-01-01

In sensor networks, nodes must often operate in a demanding environment facing restrictions such as restricted computing resources, unreliable wireless communication and power shortages. Such factors make the development of ubiquitous sensor network (USN) applications challenging. To help developers construct a large amount of node software for sensor network applications easily and rapidly, this paper proposes an approach to the automated construction of node software for USN applications using attributes. In the proposed technique, application construction proceeds by first developing a model for the sensor network and then designing node software by setting the values of the predefined attributes. After that, the sensor network model and the design of node software are verified. The final source codes of the node software are automatically generated from the sensor network model. We illustrate the efficiency of the proposed technique by using a gas/light monitoring application through a case study of a Gas and Light Monitoring System based on the Nano-Qplus operating system. We evaluate the technique using a quantitative metric—the memory size of execution code for node software. Using the proposed approach, developers are able to easily construct sensor network applications and rapidly generate a large number of node softwares at a time in a ubiquitous sensor network environment. PMID:22163678

Automated Construction of Node Software Using Attributes in a Ubiquitous Sensor Network Environment

Directory of Open Access Journals (Sweden)

JangMook Kang

2010-09-01

Full Text Available In sensor networks, nodes must often operate in a demanding environment facing restrictions such as restricted computing resources, unreliable wireless communication and power shortages. Such factors make the development of ubiquitous sensor network (USN applications challenging. To help developers construct a large amount of node software for sensor network applications easily and rapidly, this paper proposes an approach to the automated construction of node software for USN applications using attributes. In the proposed technique, application construction proceeds by first developing a model for the sensor network and then designing node software by setting the values of the predefined attributes. After that, the sensor network model and the design of node software are verified. The final source codes of the node software are automatically generated from the sensor network model. We illustrate the efficiency of the proposed technique by using a gas/light monitoring application through a case study of a Gas and Light Monitoring System based on the Nano-Qplus operating system. We evaluate the technique using a quantitative metric—the memory size of execution code for node software. Using the proposed approach, developers are able to easily construct sensor network applications and rapidly generate a large number of node softwares at a time in a ubiquitous sensor network environment.

Automated construction of node software using attributes in a ubiquitous sensor network environment.

Science.gov (United States)

Lee, Woojin; Kim, Juil; Kang, JangMook

2010-01-01

In sensor networks, nodes must often operate in a demanding environment facing restrictions such as restricted computing resources, unreliable wireless communication and power shortages. Such factors make the development of ubiquitous sensor network (USN) applications challenging. To help developers construct a large amount of node software for sensor network applications easily and rapidly, this paper proposes an approach to the automated construction of node software for USN applications using attributes. In the proposed technique, application construction proceeds by first developing a model for the sensor network and then designing node software by setting the values of the predefined attributes. After that, the sensor network model and the design of node software are verified. The final source codes of the node software are automatically generated from the sensor network model. We illustrate the efficiency of the proposed technique by using a gas/light monitoring application through a case study of a Gas and Light Monitoring System based on the Nano-Qplus operating system. We evaluate the technique using a quantitative metric-the memory size of execution code for node software. Using the proposed approach, developers are able to easily construct sensor network applications and rapidly generate a large number of node softwares at a time in a ubiquitous sensor network environment.

Non-small cell lung cancer: Spectral computed tomography quantitative parameters for preoperative diagnosis of metastatic lymph nodes

Energy Technology Data Exchange (ETDEWEB)

Yang, Fengfeng [Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001 (China); Dong, Jie [Department of Geriatrics, The First Affiliated Hospital, Harbin Medical University, Harbin 150001 (China); Wang, Xiuting; Fu, Xiaojiao [Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001 (China); Zhang, Tong, E-mail: zt415@sina.com [Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001 (China)

2017-04-15

Objective: To investigate the application value of spectral computed tomography (CT)quantitative parameters for preoperative diagnosis of metastatic lymph nodes in patients with non-small cell lung cancer (NSLC). Methods: 84 patients with suspected lung cancer who underwent chest dual-phase enhanced scan with gemstone spectral CT imaging (GSI) mode were selected. GSI quantitative parameters including normalized iodine concentrations (NIC), water concentration, slope of the spectral Hounsfield unit curve (λHU) were measured. The two-sample t test was used to statistically compare these quantitative parameters. Receiver operating characteristic (ROC) curves were drawn to establish the optimal threshold values. Results: A total of 144 lymph nodes were included, with 48 metastatic lymph nodes and 96 non-metastatic lymph nodes. The slope of the spectral Hounsfeld unit curve (λHU) measured during both arterial and venous phases were signifcantly higher in metastatic than in benign lymph nodes (P < 0.05). The area under the ROC curve (AUC = 0.951) of λHU of the arterial phase (AP) was the largest. When the optimal threshold values of λHU was 2.75, the sensitivity, specificity, and overall accuracy in the diagnosis of metastatic lymph nodes were 88.2%, 88.4%, 87.0%, respectively. Conclusion: Conventional CT diagnostic criteria established in accordance with size (lymph node maximal short axis diameter ≥10 mm) as the basis for judging metastatic lymph node. In quantitative assessment using spectral CT imaging, quantitative parameters showed higher accuracy than qualitative assessment of conventional CT based on the size for preoperative diagnosis of metastatic lymph nodes.

Dense volumetric detection and segmentation of mediastinal lymph nodes in chest CT images

Science.gov (United States)

Oda, Hirohisa; Roth, Holger R.; Bhatia, Kanwal K.; Oda, Masahiro; Kitasaka, Takayuki; Iwano, Shingo; Homma, Hirotoshi; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Schnabel, Julia A.; Mori, Kensaku

2018-02-01

We propose a novel mediastinal lymph node detection and segmentation method from chest CT volumes based on fully convolutional networks (FCNs). Most lymph node detection methods are based on filters for blob-like structures, which are not specific for lymph nodes. The 3D U-Net is a recent example of the state-of-the-art 3D FCNs. The 3D U-Net can be trained to learn appearances of lymph nodes in order to output lymph node likelihood maps on input CT volumes. However, it is prone to oversegmentation of each lymph node due to the strong data imbalance between lymph nodes and the remaining part of the CT volumes. To moderate the balance of sizes between the target classes, we train the 3D U-Net using not only lymph node annotations but also other anatomical structures (lungs, airways, aortic arches, and pulmonary arteries) that can be extracted robustly in an automated fashion. We applied the proposed method to 45 cases of contrast-enhanced chest CT volumes. Experimental results showed that 95.5% of lymph nodes were detected with 16.3 false positives per CT volume. The segmentation results showed that the proposed method can prevent oversegmentation, achieving an average Dice score of 52.3 +/- 23.1%, compared to the baseline method with 49.2 +/- 23.8%, respectively.

Harvesting wildlife affected by climate change: a modelling and management approach for polar bears.

Science.gov (United States)

Regehr, Eric V; Wilson, Ryan R; Rode, Karyn D; Runge, Michael C; Stern, Harry L

2017-10-01

The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to environmental carrying capacity ( K ). Using this model, we develop a state-dependent management framework to calculate a harvest level that (i) maintains a population above its maximum net productivity level (MNPL; the population size that produces the greatest net increment in abundance) relative to a changing K , and (ii) has a limited negative effect on population persistence.Our density-dependent relationships suggest that MNPL for polar bears occurs at approximately 0·69 (95% CI = 0·63-0·74) of K . Population growth rate at MNPL was approximately 0·82 (95% CI = 0·79-0·84) of the maximum intrinsic growth rate, suggesting relatively strong compensation for human-caused mortality.Our findings indicate that it is possible to minimize the demographic risks of harvest under climate change, including the risk that harvest will accelerate population declines driven by loss of the polar bear's sea-ice habitat. This requires that (i) the harvest rate - which could be 0 in some situations - accounts for a population's intrinsic growth rate, (ii) the harvest rate accounts for the quality of population data (e.g. lower harvest when uncertainty is large), and (iii) the harvest level is obtained by multiplying the harvest rate by an updated estimate of population size. Environmental variability, the sex and age of removed animals and risk tolerance can also affect the harvest rate. Synthesis and applications . We present a coupled modelling and management approach for wildlife that accounts for climate change and can be used to balance trade-offs among multiple conservation

The conundrum of hodgkin lymphoma nodes: To be or not to be included in the involved node radiation fields. The EORTC-GELA lymphoma group guidelines

International Nuclear Information System (INIS)

Girinsky, Theodore; Specht, Lena; Ghalibafian, Mithra; Edeline, Veronique; Bonniaud, Guillaume; Maazen, Richard van der; Aleman, Berthe; Paumier, Amaury; Meijnders, Paul; Lievens, Yolande; Noordijk, Evert; Poortmans, Philip

2008-01-01

Purpose: To develop easily applicable guidelines for the determination of initially involved lymph nodes to be included in the radiation fields. Patients and methods: Patients with supra-diaphragmatic Hodgkin lymphoma. All the imaging procedures were carried out with patients in the treatment position. The prechemotherapy PET/CT was coregistered with the postchemotherapy CT simulation for planning purposes. Initially involved lymph nodes were determined on fused prechemotherapy CT and FDG-PET imaging data. The initial assessment was verified with the postchemotherapy CT scan. Results: The classic guidelines for determining the involvement of lymph nodes were not easily applicable and did not seem to reflect the exact extent of Hodgkin lymphoma. Three simple steps were used to pinpoint involved lymph nodes. First, FDG-PET scans were meticulously analysed to detect lymph nodes that were overlooked on CT imaging. Second, any morphological and/or functional asymmetry was sought on CT and FDG-PET scans. Third, a decrease in size or the disappearance of initially visible lymph nodes on the prechemotherapy CT scan as compared to the postchemotherapy CT scan was considered as surrogate proof of initial involvement. Conclusions: All the radiological procedures should be performed on patients in the treatment position for proper coregistration. It is highly advisable that all CT and/or CT/PET scans be performed with IV contrast. Using the above-mentioned three simple guidelines, initially involved lymph nodes can be detected with very satisfactory accuracy. It is also emphasized that the classic guidelines (2, 3, 4) can always be used when deemed necessary

Reducing Data Size Inequality during Finite Element Model Separation into Superelements

Directory of Open Access Journals (Sweden)

Yu. V. Berchun

2015-01-01

Full Text Available The work considers two methods of automatic separation of final element model into super-elements to decrease computing resource demand when solving the linearly - elastic problems of solid mechanics. The first method represents an algorithm to separate a final element grid into simply connected sub-regions according to the set specific number of nodes in the super-element. The second method is based on the generation of a super-element with the set specific data size of the coefficient matrix of the system of equations of the internal nodes balance, which are eliminated during super-element transformation. Both methods are based on the theory of graphs. The data size of a matrix of coefficients is assessed on the assumption that the further solution of a task will use Holetsky’s method. Before assessment of data size, a KatkhillaMackey's (Cuthill-McKee algorithm renumbers the internal nodes of a super-element both to decrease a profile width of the appropriate matrix of the system of equations of balance and to reduce the number of nonzero elements. Test examples show work results of abovementioned methods compared in terms of inequality of generated super-element separation according to the number of nodes and data size of the coefficient matrix of the system of equations of the internal nodes balance. It is shown that the offered approach provides smaller inequality of data size of super-element matrixes, with slightly increasing inequality by the number of tops.

Helical Piezoelectric Energy Harvester and Its Application to Energy Harvesting Garments

Directory of Open Access Journals (Sweden)

Minsung Kim

2017-04-01

Full Text Available In this paper, we propose a helical piezoelectric energy harvester, examine its application to clothes in the form of an energy harvesting garment, and analyze its design and characteristics. The helical harvester is composed of an elastic core and a polymer piezoelectric strap twining the core. The fabricated harvester is highly elastic and can be stretched up to 158% of its initial length. Following the experiments using three different designs, the maximum output power is measured as 1.42 mW at a 3 MΩ load resistance and 1 Hz motional frequency. The proposed helical harvesters are applied at four positions of stretchable tight-fitting sportswear, namely shoulder, arm joint, knee, and hip. The maximum output voltage is measured as more than 20 V from the harvester at the knee position during intended body motions. In addition, electric power is also generated from this energy harvesting garment during daily human motions, which is about 3.9 V at the elbow, 3.1 V at the knee, and 4.4 V at the knee during push-up, walking, and squatting motions, respectively.

Theoretical Comparison of the Energy Conversion Efficiencies of Electrostatic Energy Harvesters

Energy Technology Data Exchange (ETDEWEB)

Kim, Chang-Kyu [Korea Polytechnic University, Siheung (Korea, Republic of)

2017-02-15

The characteristics of a new type of electrostatic energy harvesting device, called an out-of plane overlap harvester, are analyzed for the first time. This device utilizes a movable part that vibrates up and down on the surface of a wafer and a changing overlapping area between the vertical comb fingers. This operational principle enables the minimum capacitance to be close to 0 and significantly increases the energy conversion efficiency per unit volume. The characteristics of the out-of-plane overlap harvester, an in-plane gap-closing harvester, and an in-plane overlap harvester are compared in terms of the length, height, and width of the comb finger and the parasitic capacitance. The efficiency is improved as the length or the height increases and as the width or the parasitic capacitance decreases. In every case, the out-of-plane overlap harvester is able to create more energy and is, thus, preferable over other designs. It is also free from collisions between two electrodes caused by random vibration amplitudes and creates more energy from off axis perturbations. This device, given its small feature size, is expected to provide more energy to various types of wireless electronics devices and to offer high compatibility with other integrated circuits and ease of embedment.

Evaluation of physical structure value in spring-harvested grass/clover silage and hay fed to heifers

DEFF Research Database (Denmark)

Schulze, A.K.S.; Nørgaard, P.; Byskov, M.V.

2015-01-01

The physical structure value of conserved grass/clover forages of spring harvest was evaluated by assessing effects of harvest time, conservation method, iNDF/NDF ratio and NDF intake (NDFI) per kg BW on chewing activity and fecal particle size in dairy heifers. A mixed sward consisting of ryegrass...

Support vector machine model for diagnosis of lymph node metastasis in gastric cancer with multidetector computed tomography: a preliminary study

International Nuclear Information System (INIS)

Zhang, Xiao-Peng; Wang, Zhi-Long; Tang, Lei; Sun, Ying-Shi; Cao, Kun; Gao, Yun

2011-01-01

Lymph node metastasis (LNM) of gastric cancer is an important prognostic factor regarding long-term survival. But several imaging techniques which are commonly used in stomach cannot satisfactorily assess the gastric cancer lymph node status. They can not achieve both high sensitivity and specificity. As a kind of machine-learning methods, Support Vector Machine has the potential to solve this complex issue. The institutional review board approved this retrospective study. 175 consecutive patients with gastric cancer who underwent MDCT before surgery were included. We evaluated the tumor and lymph node indicators on CT images including serosal invasion, tumor classification, tumor maximum diameter, number of lymph nodes, maximum lymph node size and lymph nodes station, which reflected the biological behavior of gastric cancer. Univariate analysis was used to analyze the relationship between the six image indicators with LNM. A SVM model was built with these indicators above as input index. The output index was that lymph node metastasis of the patient was positive or negative. It was confirmed by the surgery and histopathology. A standard machine-learning technique called k-fold cross-validation (5-fold in our study) was used to train and test SVM models. We evaluated the diagnostic capability of the SVM models in lymph node metastasis with the receiver operating characteristic (ROC) curves. And the radiologist classified the lymph node metastasis of patients by using maximum lymph node size on CT images as criterion. We compared the areas under ROC curves (AUC) of the radiologist and SVM models. In 175 cases, the cases of lymph node metastasis were 134 and 41 cases were not. The six image indicators all had statistically significant differences between the LNM negative and positive groups. The means of the sensitivity, specificity and AUC of SVM models with 5-fold cross-validation were 88.5%, 78.5% and 0.876, respectively. While the diagnostic power of the

Implementation of a robust hybrid rotary-translational vibration energy harvester for autonomous self-powered acceleration measurement

Science.gov (United States)

Payne, Owen R.; Vandewater, Luke A.; Ung, Chandarin; Moss, Scott D.

2015-04-01

In this paper, a self-powered wireless sensor node utilising ambient vibrations for power is described. The device consists of a vibration energy harvester, power management system, microcontroller, accelerometer, RF transmitter/receiver and external LED indicators. The vibration energy harvester is adapted from a previously reported hybrid rotary-translational device and uses a pair of copper coil transducers to convert the mechanical energy of a magnetic sphere into usable electricity. The device requires less than 0.8 mW of power to operate continuously in its present setup (with LED indicators off) while measuring acceleration at a sample rate of 200 Hz, with the power source providing 39.7 mW of power from 500 mg excitations at 5.5 Hz. When usable input energy is removed, the device will continue to transmit data for more than 5 minutes.

Acquisition Of Rainfall Dataset And The Application For The Automatic Harvester In The Chesapeake Bay Region

Science.gov (United States)

Choi, Y.; Piasecki, M.

2008-12-01

The objective of this study is the preparation and indexing of rainfall data products for ingestion into the Chesapeake Bay Environmental Observatory (CBEO) node of the CUAHSI/WATERs network. Rainfall products (which are obtained and then processed based on the WSR-88D NEXRAD network) are obtained from the NOAA/NWS Advanced Hydrologic Prediction Service that combines the Multi-sensor Precipitation Estimate (MPE) data generated by the Regional River Forecast Centers and Hydro-NEXRAD rainfall data generated as a service by the University of Iowa. The former is collected on 4*4 km grid (HRAP) with a daily average temporal resolution and the latter on a 1minute*1minute degree grid with hourly values. We have generated a cut-out for the Chesapeake Bay Basin that contains about 9,300 nodes (sites) for the MPE data and about 300,000 nodes (sites) for the Hydro-NEXRAD product. Automated harvesting services have been implemented for both data products. The MPE data is harvested from its download site using ArcGIS which in turn is used to extract the data for the Chesapeake Bay watershed before a scripting program is used to scatter the data into the ODM. The Hydro-NEXRAD is downloaded from a web-based system at the University of Iowa which permits downloads for large scale watersheds organized by Hydraulic Unit Codes (HUC). The resulting ASCII is then automatically parsed and the information stored alongside the MPE data. The two data products stored side-by-side then allows a comparison between them addressing the accuracy and agreement between the methods used to arrive at rainfall data as both use the raw reflectivity data from the WSD-88D system.

Implementation of Multiple Host Nodes in Wireless Sensing Node Network System for Landslide Monitoring

International Nuclear Information System (INIS)

Bin Abas, Faizulsalihin; Takayama, Shigeru

2015-01-01

This paper proposes multiple host nodes in Wireless Sensing Node Network System (WSNNS) for landslide monitoring. As landslide disasters damage monitoring system easily, one major demand in landslide monitoring is the flexibility and robustness of the system to evaluate the current situation in the monitored area. For various reasons WSNNS can provide an important contribution to reach that aim. In this system, acceleration sensors and GPS are deployed in sensing nodes. Location information by GPS, enable the system to estimate network topology and enable the system to perceive the location in emergency by monitoring the node mode. Acceleration sensors deployment, capacitate this system to detect slow mass movement that can lead to landslide occurrence. Once deployed, sensing nodes self-organize into an autonomous wireless ad hoc network. The measurement parameter data from sensing nodes is transmitted to Host System via host node and ''Cloud'' System. The implementation of multiple host nodes in Local Sensing Node Network System (LSNNS), improve risk- management of the WSNNS for real-time monitoring of landslide disaster

Implementation of Multiple Host Nodes in Wireless Sensing Node Network System for Landslide Monitoring

Science.gov (United States)

Abas, Faizulsalihin bin; Takayama, Shigeru

2015-02-01

This paper proposes multiple host nodes in Wireless Sensing Node Network System (WSNNS) for landslide monitoring. As landslide disasters damage monitoring system easily, one major demand in landslide monitoring is the flexibility and robustness of the system to evaluate the current situation in the monitored area. For various reasons WSNNS can provide an important contribution to reach that aim. In this system, acceleration sensors and GPS are deployed in sensing nodes. Location information by GPS, enable the system to estimate network topology and enable the system to perceive the location in emergency by monitoring the node mode. Acceleration sensors deployment, capacitate this system to detect slow mass movement that can lead to landslide occurrence. Once deployed, sensing nodes self-organize into an autonomous wireless ad hoc network. The measurement parameter data from sensing nodes is transmitted to Host System via host node and "Cloud" System. The implementation of multiple host nodes in Local Sensing Node Network System (LSNNS), improve risk- management of the WSNNS for real-time monitoring of landslide disaster.

Morphology of bone particles after harvesting with 4 different devices.

Science.gov (United States)

Papadimitriou, Dimitrios E V; Schmidt, Erich C; Caton, Jack G; Romanos, Georgios E

2013-04-01

Autogenous bone is routinely used for regeneration of osseous defects around teeth and implants, and different instruments are available for bone harvesting. The purpose of this study was to describe the morphology of bone particles after harvesting with 4 different instruments. Bone particles were harvested from fresh cow ribs with 2 different types of back action chisels, a safescraper and a sonic device. The samples were examined morphologically using light microscopy and scanning electron microscopy. The bone particles after the back action chisel I had an appearance similar to "pencil shavings." With the back action chisel II, they were like thin paper with an "accordion bellows" appearance. After removal with the safescraper, they had an irregular shape (with an irregular surface) resembling "crushed stone." Finally, the appearance of the bone particles obtained with the sonic device was homogenous, condensed and continuous, and had a "seaweed" appearance. Harvesting of bone particles with 4 different devices produce distinctly difference sizes and shapes, which may influence the results of grafting procedures.

Comparing fishers' and scientific estimates of size at maturity and maximum body size as indicators for overfishing.

Science.gov (United States)

Mclean, Elizabeth L; Forrester, Graham E

2018-04-01

We tested whether fishers' local ecological knowledge (LEK) of two fish life-history parameters, size at maturity (SAM) at maximum body size (MS), was comparable to scientific estimates (SEK) of the same parameters, and whether LEK influenced fishers' perceptions of sustainability. Local ecological knowledge was documented for 82 fishers from a small-scale fishery in Samaná Bay, Dominican Republic, whereas SEK was compiled from the scientific literature. Size at maturity estimates derived from LEK and SEK overlapped for most of the 15 commonly harvested species (10 of 15). In contrast, fishers' maximum size estimates were usually lower than (eight species), or overlapped with (five species) scientific estimates. Fishers' size-based estimates of catch composition indicate greater potential for overfishing than estimates based on SEK. Fishers' estimates of size at capture relative to size at maturity suggest routine inclusion of juveniles in the catch (9 of 15 species), and fishers' estimates suggest that harvested fish are substantially smaller than maximum body size for most species (11 of 15 species). Scientific estimates also suggest that harvested fish are generally smaller than maximum body size (13 of 15), but suggest that the catch is dominated by adults for most species (9 of 15 species), and that juveniles are present in the catch for fewer species (6 of 15). Most Samaná fishers characterized the current state of their fishery as poor (73%) and as having changed for the worse over the past 20 yr (60%). Fishers stated that concern about overfishing, catching small fish, and catching immature fish contributed to these perceptions, indicating a possible influence of catch-size composition on their perceptions. Future work should test this link more explicitly because we found no evidence that the minority of fishers with more positive perceptions of their fishery reported systematically different estimates of catch-size composition than those with the more

Dynamically reassigning a connected node to a block of compute nodes for re-launching a failed job

Science.gov (United States)

Budnik, Thomas A [Rochester, MN; Knudson, Brant L [Rochester, MN; Megerian, Mark G [Rochester, MN; Miller, Samuel J [Rochester, MN; Stockdell, William M [Byron, MN

2012-03-20

Methods, systems, and products for dynamically reassigning a connected node to a block of compute nodes for re-launching a failed job that include: identifying that a job failed to execute on the block of compute nodes because connectivity failed between a compute node assigned as at least one of the connected nodes for the block of compute nodes and its supporting I/O node; and re-launching the job, including selecting an alternative connected node that is actively coupled for data communications with an active I/O node; and assigning the alternative connected node as the connected node for the block of compute nodes running the re-launched job.

Structural Optimization of Triboelectric Nanogenerator for Harvesting Water Wave Energy.

Science.gov (United States)

Jiang, Tao; Zhang, Li Min; Chen, Xiangyu; Han, Chang Bao; Tang, Wei; Zhang, Chi; Xu, Liang; Wang, Zhong Lin

2015-12-22

Ocean waves are one of the most abundant energy sources on earth, but harvesting such energy is rather challenging due to various limitations of current technologies. Recently, networks formed by triboelectric nanogenerator (TENG) have been proposed as a promising technology for harvesting water wave energy. In this work, a basic unit for the TENG network was studied and optimized, which has a box structure composed of walls made of TENG composed of a wavy-structured Cu-Kapton-Cu film and two FEP thin films, with a metal ball enclosed inside. By combination of the theoretical calculations and experimental studies, the output performances of the TENG unit were investigated for various structural parameters, such as the size, mass, or number of the metal balls. From the viewpoint of theory, the output characteristics of TENG during its collision with the ball were numerically calculated by the finite element method and interpolation method, and there exists an optimum ball size or mass to reach maximized output power and electric energy. Moreover, the theoretical results were well verified by the experimental tests. The present work could provide guidance for structural optimization of wavy-structured TENGs for effectively harvesting water wave energy toward the dream of large-scale blue energy.

Value of irradiation of neck nodes metastases. Pt. 1. Treatment of palpable nodes

International Nuclear Information System (INIS)

Bujko, K.

1993-01-01

Medical records of 222 patients with neck nodes metastases from squamous cell carcinoma of supraglottic larynx, tonsil and base of tongue were analyzed. All cases were treated with definitive irradiation. 110 patients were treated with orthovoltage technique with total doses of 5000-6000 rads, 150-10 rads per fraction; 112 patients with Co-60 with total doses 6000-7000 rads, 180-230 rads per fraction. Local-regional control was achieved in 28% of cases. Failures in the neck nodes with primary tumor controlled, were recorded in 10% of patients. Failures in a primary tumor alone were observed in 26% of patients, in primary tumor and neck nodes in 36%. Radiocurability of primary tumor and involved neck nodes was similar. In cases with primary tumor controlled, the probability of eradication of neck nodes metastases is high, even in N3 stage patients. Residual neck nodes palpable 1 to 3 months after irradiation were unfavorable prognostic factor indicated 50% risk of neck recurrence. In patients with complete regression of primary and nodal disease, failure in neck nodes was recorded in 5% of cases. The role of surgery following irradiation in patients with cervical nodes metastases is discussed. (author)

Hybrid tracers for sentinel node biopsy

International Nuclear Information System (INIS)

Van Den Berg, N. S.; Kleinjan, G. I.; Valdés-Olmos, R. A.; Buckle, T.; Van Leeuwen, F. I.; Klop, W. M.; Horenblas, S.; Van Der Poel, H. G.

2014-01-01

Conventional sentinel node (SN) mapping is performed by injection of a radiocolloid followed by lymphoscintigraphy to identify the number and location of the primary tumor draining lymph node(s), the so-called SN(s). Over the last decade research has focused on the introduction of new imaging agents that can further aid (surgical) SN identification. Different tracers for SN mapping, with varying sizes and isotopes have been reported, most of which have proven their value in a clinical setting. A major challenge lies in transferring this diagnostic information obtained at the nuclear medicine department to the operating theatre thereby providing the surgeon with (image) guidance. Conventionally, an intraoperative injection of vital blue dye or a fluorescence dye is given to allow intraoperative optical SN identification. However, for some indications, the radiotracer-based approach remains crucial. More recently, hybrid tracers, that contain both a radioactive and fluorescent label, were introduced to allow for direct integration of pre- and intraoperative guidance technologies. Their potential is especially high when they are used in combination with new surgical imaging modalities and navigation tools. Next to a description of the known tracers for SN mapping, this review discusses the application of hybrid tracers during SN biopsy and how the introduction of these new techniques can further aid in translation of nuclear medicine information into the operating theatre.

Low temperature and Daphnia-associated infochemicals promote colony formation of Scenedesmus obliquus and its harvesting.

Science.gov (United States)

Zhu, Xuexia; Yang, Jingwen; Zhang, Xingxing; Zhang, Lu; Wang, Xiaojun; Huang, Yuan; Yang, Zhou

2017-01-01

To explore the combined effects of temperature and Daphnia-associated infochemicals on colony formation of Scenedesmus obliquus to faciliate harvesting the algal biomass. A three-parameter modified Gaussian model fitted the changes of the number of cells per particle in S. obliquus induced by Daphnia culture filtrate well under any temperature. Decreases in temperature enhanced the induced-colony formation of Scenedesmus. The maximum colony size at 15-25 °C was significantly larger than those at 30-35 °C. An additional 1 or 2 days at low temperature was needed to reach the maximum colony size, which indicates the best harvest time for algal biomass. Induced-colony formation of Scenedesmus by Daphnia culture filtrate at 15-25 °C is recommended to settle algal cells. This condition facilitates harvesting the biomass.

Expansion of lymph node metastasis in mixed-type submucosal invasive gastric cancer.

Science.gov (United States)

Mikami, Koji; Hirano, Yukiko; Futami, Kitaro; Maekawa, Takafumi

2017-07-18

Mixed-type early gastric cancer (differentiated and undifferentiated components) incurs a higher risk of lymph node metastasis than pure-type early gastric cancer (only differentiated or only undifferentiated components). Therefore, we investigated the expansion of lymph node metastasis in mixed-type submucosal invasive gastric cancer in order to establish the most appropriate treatment for mixed-type cancer. We retrospectively analyzed 279 consecutive patients with submucosal invasive gastric cancer who underwent curative gastrectomy for gastric cancer between 1996 and 2015. We classified the patients into the mixed-type and pure-type groups according to histologic examination and evaluated the expansion of lymph node metastasis. The rate of lymph node metastasis was 23.7% (66/279) in the total patients, 36.4% (36/99) in the mixed-type group, and 16.6% (30/180) in the pure-type group. The significant independent risk factors for lymph node metastasis were tumor size ≥2.0 cm (P = 0.014), mixed-type gastric cancer (P mixed-type group. The rates of no. 7 lymph node metastasis in the total patients and mixed-type group were 2.9% (8/279) and 5.1% (5/99), respectively; the rates of no. 8a lymph node metastasis were 1.4% (4/279) and 4.0% (4/99), respectively. Mixed histological type is an independent risk factor for lymph node metastasis. Lymph node metastasis in mixed-type gastric cancer involves expansion to the no. 7 and no. 8a lymph nodes. Therefore, lymphadenectomy for mixed-type submucosal invasive gastric cancer requires D1+ or D2 dissection. Copyright © 2017. Published by Elsevier Taiwan.

The application of phase grating to CLM technology for the sub-65nm node optical lithography

Science.gov (United States)

Yoon, Gi-Sung; Kim, Sung-Hyuck; Park, Ji-Soong; Choi, Sun-Young; Jeon, Chan-Uk; Shin, In-Kyun; Choi, Sung-Woon; Han, Woo-Sung

2005-06-01

As a promising technology for sub-65nm node optical lithography, CLM(Chrome-Less Mask) technology among RETs(Resolution Enhancement Techniques) for low k1 has been researched worldwide in recent years. CLM has several advantages, such as relatively simple manufacturing process and competitive performance compared to phase-edge PSM's. For the low-k1 lithography, we have researched CLM technique as a good solution especially for sub-65nm node. As a step for developing the sub-65nm node optical lithography, we have applied CLM technology in 80nm-node lithography with mesa and trench method. From the analysis of the CLM technology in the 80nm lithography, we found that there is the optimal shutter size for best performance in the technique, the increment of wafer ADI CD varied with pattern's pitch, and a limitation in patterning various shapes and size by OPC dead-zone - OPC dead-zone in CLM technique is the specific region of shutter size that dose not make the wafer CD increased more than a specific size. And also small patterns are easily broken, while fabricating the CLM mask in mesa method. Generally, trench method has better optical performance than mesa. These issues have so far restricted the application of CLM technology to a small field. We approached these issues with 3-D topographic simulation tool and found that the issues could be overcome by applying phase grating in trench-type CLM. With the simulation data, we made some test masks which had many kinds of patterns with many different conditions and analyzed their performance through AIMS fab 193 and exposure on wafer. Finally, we have developed the CLM technology which is free of OPC dead-zone and pattern broken in fabrication process. Therefore, we can apply the CLM technique into sub-65nm node optical lithography including logic devices.

Clinical value and indication for the dissection of lymph nodes posterior to the right recurrent laryngeal nerve in papillary thyroid carcinoma.

Science.gov (United States)

Luo, Ding-Cun; Xu, Xiao-Cheng; Ding, Jin-Wang; Zhang, Yu; Peng, You; Pan, Gang; Zhang, Wo

2017-10-03

Lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) are common sites of nodal recurrence after the resection of papillary thyroid carcinoma (PTC). However, the indication for LN-prRLN dissection remains debatable. We therefore studied the relationships between LN-prRLN metastasis and the clinicopathological characteristics in 306 patients with right or bilateral PTC who underwent LN-prRLN dissection. We found that LN-prRLN metastasis occurred in 16.67% of PTC and was associated with a number of the clinicopathological features. The receiver-operator characteristic (ROC) analysis showed that the areas under the ROC curves for the prediction of LN-prRLN metastasis by the risk factors age right tumor size > 0.85 cm, lymph node (right cervical central VI-1) number > 1.5, metastatic lymph node (right cervical central VI-1) size > 0.45 cm, and lymph node number in the right cervical lateral compartment > 0.5 were 0.601, 0.815, 0.813, 0.725, and 0.743, respectively. In conclusion, the risk factors for LN-prRLN metastasis in patients suffering right thyroid lobe or bilateral PTC include age ≤ 35.5 years, right tumor size ≥ 0.85 cm, capsular invasion, metastatic lymph node (right cervical central VI-1) number ≥ 2, metastatic lymph node (right cervical central VI-1) size ≥ 0.45 cm, and metastatic lymph node number in the right cervical lateral compartment ≥ 1. In patients whose risk factors can be identified pre-operatively or intraoperatively, the dissection of LN-pr-RLN should be considered during right cervical central compartment dissection.

A critical reappraisal of false negative sentinel lymph node biopsy in melanoma

International Nuclear Information System (INIS)

Manca, G.; Mazzarri, S.; Boni, G.; Chiacchio, S.; Tredici, M.; Duce, V.; Tardelli, E.; Volterrani, D.; Mariani, G.; Romanini, A.; Rubello, D.

2014-01-01

Lymphatic mapping and sentinel lymph node biopsy (SLNB) have completely changed the clinical management of cutaneous melanoma. This procedure has been accepted worldwide as a recognized method for nodal staging. SLNB is able to accurately determine nodal basin status, providing the most useful prognostic information. However, SLNB is not a perfect diagnostic test. Several large-scale studies have reported a relatively high false-negative rate (5.6-21%), correctly defined as the proportion of false-negative results with respect to the total number of “actual” positive lymph nodes. The main purpose of this review is to address the technical issues that nuclear physicians, surgeons, and pathologists should carefully consider to improve the accuracy of SLNB by minimizing its false-negative rate. In particular, SPECT/CT imaging has demonstrated to be able to identify a greater number of sentinel lymph nodes (SLNs) than those found by planar lymphoscintigraphy. Furthermore, a unique definition in the international guidelines is missing for the operational identification of SLNs, which may be partly responsible for this relatively high false-negative rate of SLNB. Therefore, it is recommended for the scientific community to agree on the radioactive counting rate threshold so that the surgeon can be better radioguided to detect all the lymph nodes which are most likely to harbor metastases. Another possible source of error may be linked to the examination of the harvested SLNs by conventional histopathological methods. A more careful and extensive SLN analysis (e.g. molecular analysis by RT-PCR) is able to find more positive nodes, so that the false-negative rate is reduced. Older age at diagnosis, deeper lesions, histologic ulceration, head-neck anatomical location of primary lesions are the clinical factors associated with false-negative SLNBs in melanoma patients. There is still much controversy about the clinical significance of a false-negative SLNB on the

The distribution of the number of node neighbors in random hypergraphs

International Nuclear Information System (INIS)

López, Eduardo

2013-01-01

Hypergraphs, the generalization of graphs in which edges become conglomerates of r nodes called hyperedges of rank r ⩾ 2, are excellent models to study systems with interactions that are beyond the pairwise level. For hypergraphs, the node degree ℓ (number of hyperedges connected to a node) and the number of neighbors k of a node differ from each other in contrast to the case of graphs, where counting the number of edges is equivalent to counting the number of neighbors. In this paper, I calculate the distribution of the number of node neighbors in random hypergraphs in which hyperedges of uniform rank r have a homogeneous (equal for all hyperedges) probability p to appear. This distribution is equivalent to the degree distribution of ensembles of graphs created as projections of hypergraph or bipartite network ensembles, where the projection connects any two nodes in the projected graph when they are also connected in the hypergraph or bipartite network. The calculation is non-trivial due to the possibility that neighbor nodes belong simultaneously to multiple hyperedges (node overlaps). From the exact results, the traditional asymptotic approximation to the distribution in the sparse regime (small p) where overlaps are ignored is rederived and improved; the approximation exhibits Poisson-like behavior accompanied by strong fluctuations modulated by power-law decays in the system size N with decay exponents equal to the minimum number of overlapping nodes possible for a given number of neighbors. It is shown that the dense limit cannot be explained if overlaps are ignored, and the correct asymptotic distribution is provided. The neighbor distribution requires the calculation of a new combinatorial coefficient Q r−1 (k, ℓ), which counts the number of distinct labeled hypergraphs of k nodes, ℓ hyperedges of rank r − 1, and where every node is connected to at least one hyperedge. Some identities of Q r−1 (k, ℓ) are derived and applied to the

Clinicopathologic risk factors for right paraesophageal lymph node metastasis in patients with papillary thyroid carcinoma.

Science.gov (United States)

Yu, Q A; Ma, D K; Liu, K P; Wang, P; Xie, C M; Wu, Y H; Dai, W J; Jiang, H C

2018-03-17

To investigate risk factors associated with right paraesophageal lymph node (RPELN) metastasis in patients with papillary thyroid carcinoma (PTC) and to determine the indications for right lymph node dissection. Clinicopathologic data from 829 patients (104 men and 725 women) with PTC, operated on by the same thyroid surgery team at the First Affiliated Hospital of Harbin Medical University from January 2013 to May 2017, were analyzed. Overall, 309 patients underwent total thyroidectomy with bilateral lymph node dissection, 488 underwent right thyroid lobe and isthmic resection with right central compartment lymph node dissection, and 32 underwent near-total thyroidectomy (ipsilateral thyroid lobectomy with contralateral near-total lobectomy) with bilateral lymph node dissection. The overall rate of central compartment lymph node metastasis was 43.5% (361/829), with right central compartment lymph node and RPELN metastasis rates of 35.5% (294/829) and 19.1% (158/829), respectively. Tumor size, number, invasion, and location, lymph node metastasis, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis were associated with RPELN in the univariate analysis, whereas age and sex were not. Multivariate analysis identified tumors with a diameter ≥ 1 cm, multiple tumors, tumors located in the right lobe, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis as independent risk factors for RPELN metastasis. Lymph node dissection, including RPELN dissection, should be performed for patients with PTC with a tumor diameter ≥ 1 cm, multiple tumors, right-lobe tumors, right central compartment lymph node metastasis, or suspected lateral compartment lymph node metastasis.

Post-mastectomy radiation in large node-negative breast tumors: Does size really matter?

International Nuclear Information System (INIS)

Floyd, Scott R.; Taghian, Alphonse G.

2009-01-01

Treatment decisions regarding local control can be particularly challenging for T3N0 breast tumors because of difficulty in estimating rates of local failure after mastectomy. Reports in the literature detailing the rates of local failure vary widely, likely owing to the uncommon incidence of this clinical situation. The literature regarding this clinical scenario is reviewed, including recent reports that specifically address the issue of local failure rates after mastectomy in the absence of radiation for large node-negative breast tumors.

Rainwater harvesting - An investigation into the potential for rainwater harvesting in Bradford

OpenAIRE

Doncaster, S.; Blanksby, J.; Shepherd, W.

2012-01-01

This report provides a brief review of rainwater harvesting and rainwater harvesting tools, which are then used in case study examples for domestic, office block and warehouse rain water harvesting scenarios. Rainwater harvesting is placed in an historical context as a source of water supply and in a modern context as being complementary to centralised water distribution networks with benefits for wider water management including flood risk treatment as well as providing environmental and eco...

Concordance between peri-areolar blue dye and peri-incisional radiotracer injections for sentinel node mapping in patients with a history of primary breast cancer excisonal biopsy.

Science.gov (United States)

Mehrabibahar, M; Azizi, S; Jangjoo, A; Saremi, E; Kakhki, V R Dabbagh; Sadeghi, R; Chicken, D W; Keshtgar, M

2014-01-01

We evaluated the concordance between peri-areolar blue dye and peri-incisional radiotracer injections for axillary sentinel node mapping of patients with the history of previous breast lesion excisional biopsy. 80 patients with the history of previous excisional biopsy of the breast lesions were included. All patients received two injections of 99mTc-antimony sulfide colloid in both ends of incision line in an intradermal fashion. 2 mL patient blue V dye was injection to all patients in the peri-areolar area of the index quadrant after induction of anesthesia. All blue or hot nodes were harvested as sentinel lymph nodes. At least one sentinel node could be detected during surgery in 79 patients. In total 94 sentinel nodes were detected. All detected sentinel nodes were hot. In three patients sentinel nodes were detected by gamma probe but not blue dye. The tumor location in all of these patients was in the upper lateral quadrant and the incision line was extended into the axillary tail of the breast in all of them. 91 out of 94 sentinel nodes were stained blue, which amounts to 95.8% concordance between blue dye and radiotracer on a per node analysis. Single peri-areolar injection in the index quadrant would suffice for sentinel node mapping of patients with history of excisional biopsy. Care should be taken in patients with large excisional biopsy in the extreme proximity to axilla.

Bundling harvester; Nippukorjausharvesteri

Energy Technology Data Exchange (ETDEWEB)

Koponen, K [Eko-Log Oy, Kuopio (Finland)

1997-12-31

The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilized without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilization of wood-energy

Bundling harvester; Nippukorjausharvesteri

Energy Technology Data Exchange (ETDEWEB)

Koponen, K. [Eko-Log Oy, Kuopio (Finland)

1996-12-31

The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilized without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilization of wood-energy

Roles of preoperative lymphoscintigraphy for sentinel lymph node biopsy in breast cancer patients

International Nuclear Information System (INIS)

Sun Xiao; Liu Juanjuan; Wang Yongsheng; Wang Lei; Yang Guoren; Zhou Zhengbo; Li Yongqing; Liu Yanbing; Li Taiyu

2010-01-01

The objective of this study was to evaluate roles of preoperative lymphoscintigraphy for sentinel lymph node biopsy in breast cancer patients. Five hundred and sixty-five consecutive breast cancer patients were prospectively randomized into groups with or without preoperative lymphoscintigraphy. In a group with lymphoscintigraphy, 238 patients had sentinel lymph nodes spotted in lymphoscintigram. The visualization of sentinel lymph nodes in lymphoscintigram was not associated with patients' age, primary tumor size and location, histopathologic type and time interval from injection of radiocolloid to lymphoscintigraphy. However, patients with axillary metastasis had a lower identification rate of sentinel lymph nodes by lymphoscintigraphy than those without metastasis (P=0.003). The identification rate of axillary sentinel lymph nodes was 99.3% in the group and the rate was similar whether there was sentinel lymph nodes spotted in axillary in lymphoscintigram or not (99.6% vs. 98.1%, P=0.327). The false-negative rate in this group was 4.2%. While in a group without lymphoscintigraphy, the identification rate and the false-negative rate were 99.6% and 4.8%, respectively. There was no significant difference between the two groups in the identification rate of axillary sentinel lymph nodes (P=0.594) and in the false-negative rate (P=1.00). Preoperative lymphoscintigraphy could neither improve the identification rate nor reduce the false-negative rate of breast cancer sentinel lymph node biopsy, and it is not necessary for sentinel lymph node biopsy in breast cancer patients. (author)

Demographic evidence of illegal harvesting of an endangered asian turtle.

Science.gov (United States)

Sung, Yik-Hei; Karraker, Nancy E; Hau, Billy C H

2013-12-01

Harvesting pressure on Asian freshwater turtles is severe, and dramatic population declines of these turtles are being driven by unsustainable collection for food markets, pet trade, and traditional Chinese medicine. Populations of big-headed turtle (Platysternon megacephalum) have declined substantially across its distribution, particularly in China, because of overcollection. To understand the effects of chronic harvesting pressure on big-headed turtle populations, we examined the effects of illegal harvesting on the demography of populations in Hong Kong, where some populations still exist. We used mark-recapture methods to compare demographic characteristics between sites with harvesting histories and one site in a fully protected area. Sites with a history of illegal turtle harvesting were characterized by the absence of large adults and skewed ratios of juveniles to adults, which may have negative implications for the long-term viability of populations. These sites also had lower densities of adults and smaller adult body sizes than the protected site. Given that populations throughout most of the species' range are heavily harvested and individuals are increasingly difficult to find in mainland China, the illegal collection of turtles from populations in Hong Kong may increase over time. Long-term monitoring of populations is essential to track effects of illegal collection, and increased patrolling is needed to help control illegal harvesting of populations, particularly in national parks. Because few, if any, other completely protected populations remain in the region, our data on an unharvested population of big-headed turtles serve as an important reference for assessing the negative consequences of harvesting on populations of stream turtles. Evidencia Demográfica de la Captura Ilegal de una Tortuga Asiática en Peligro. © 2013 Society for Conservation Biology.

Control range: a controllability-based index for node significance in directed networks

International Nuclear Information System (INIS)

Wang, Bingbo; Gao, Lin; Gao, Yong

2012-01-01

While a large number of methods for module detection have been developed for undirected networks, it is difficult to adapt them to handle directed networks due to the lack of consensus criteria for measuring the node significance in a directed network. In this paper, we propose a novel structural index, the control range, motivated by recent studies on the structural controllability of large-scale directed networks. The control range of a node quantifies the size of the subnetwork that the node can effectively control. A related index, called the control range similarity, is also introduced to measure the structural similarity between two nodes. When applying the index of control range to several real-world and synthetic directed networks, it is observed that the control range of the nodes is mainly influenced by the network's degree distribution and that nodes with a low degree may have a high control range. We use the index of control range similarity to detect and analyze functional modules in glossary networks and the enzyme-centric network of homo sapiens. Our results, as compared with other approaches to module detection such as modularity optimization algorithm, dynamic algorithm and clique percolation method, indicate that the proposed indices are effective and practical in depicting structural and modular characteristics of sparse directed networks

Sentinel nodes outside lymph node basins in patients with melanoma

NARCIS (Netherlands)

Roozendaal, GK; de Vries, JDH; van Poll, D; Jansen, L; Nieweg, OE; Kroon, BBR; Schraffordt Koops, H.

Background: Lymphoscintigraphy occasionally reveals hot spots outside lymph node basins in patients with melanoma. The aim of this study was to evaluate such abnormally located hot spots. Methods: Sentinel node biopsy was studied prospectively in 379 patients with clinically localized cutaneous

Harvest time and post-harvest quality of Fuyu persimmon treated before harvest with gibberellic acid and aminoetoxyvinilglycine

Directory of Open Access Journals (Sweden)

Ricardo Antonio Ayub

2008-12-01

Full Text Available The aim of this work was to evaluate the effects of gibberellic acid (GA3 and aminoetoxyvinilglycine (AVG applied in preharvest spraying, on the retardation of the harvest and on the quality of persimmon fruits cv. Fuyu. The experiment was carried in randomized complete block design. The treatments were: control, 136mgL-1 of AVG, 272 mgL-1 of AVG, 36mgL-1 of GA3, 72mgL-1 of GA3 and 136mgL-1 of AVG + 36mgL-1 of GA3, spraying 30 days before the first harvest. The fruits were harvested twice and stored at 4ºC. The chemical and physical evaluations of the fruits were carried out the date of the harvest and at intervals of 15 days followed by four days at 20ºC. In conclusion, the application of AVG (136mgL-1 or GA3 (72mgL-1 maintained the firmness of the fruits and delayed harvest by twenty days. However, fruits harvested in the initial state of ripening were more sensitive to chilling injury and were unable to support 15 days of storage at 4ºC. The plant growth regulators were not efficient in prolonged storage due to the fact that the concentration of sugars was lower in the treatments than in the control.

Buffer sizing for multi-hop networks

KAUST Repository

Shihada, Basem

2014-01-28

A cumulative buffer may be defined for an interference domain in a wireless mesh network and distributed among nodes in the network to maintain or improve capacity utilization of network resources in the interference domain without increasing packet queuing delay times. When an interference domain having communications links sharing resources in a network is identified, a cumulative buffer size is calculated. The cumulative buffer may be distributed among buffers in each node of the interference domain according to a simple division or according to a cost function taking into account a distance of the communications link from the source and destination. The network may be monitored and the cumulative buffer size recalculated and redistributed when the network conditions change.

Energy Efficient Routing and Node Activity Scheduling in the OCARI Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Saoucene Mahfoudh

2010-08-01

Full Text Available Sensor nodes are characterized by a small size, a low cost, an advanced communication technology, but also a limited amount of energy. Energy efficient strategies are required in such networks to maximize network lifetime. In this paper, we focus on a solution integrating energy efficient routing and node activity scheduling. The energy efficient routing we propose, called EOLSR, selects the route and minimizes the energy consumed by an end-to-end transmission, while avoiding nodes with low residual energy. Simulation results show that EOLSR outperforms the solution selecting the route of minimum energy as well as the solution based on node residual energy. Cross-layering allows EOLSR to use information from the application layer or the MAC layer to reduce its overhead and increase network lifetime. Node activity scheduling is based on the following observation: the sleep state is the least power consuming state. So, to schedule node active and sleeping periods, we propose SERENA that colors all network nodes using a small number of colors, such that two nodes with the same color can transmit without interfering. The node color is mapped into a time slot during which the node can transmit. Consequently, each node is awake during its slot and the slots of its one-hop neighbors, and sleeps in the remaining time. We evaluate SERENA benefits obtained in terms of bandwidth, delay and energy. We also show how cross-layering with the application layer can improve the end-to-end delays for data gathering applications.

[Flow cytometry in datecting lymph node micrometastasis in colorectal cancer].

Science.gov (United States)

Sun, Q; Ding, Y; Zhang, J

2001-01-25

To study the methodology and significance of flow cytometry in detecting lymph node micrometastasis of colorectal cancer. One hundred sixty-two cellular suspensions were prepared with lymph nodes which were resected radically on 25 patients with colorectal cancer and in which no cancer cells were found by HE staining. Different concentrations of cultured Lovo colorectal cancer cells were added into the celular suspension prepared from lymph node tissue of persons without colorectal cancer in order to prepare a control model. Dual staining with CK/FTTC and PI was made to the sedimetns from those 2 kinds of suspension. Flow cytometry was used to detect cancer cells. An ideal correlation was obtained between the detection value and the theoretical value of cancer cells in the specimen suspensions and control models (r = 0.097 6) with a sensitivity rate of 10/10(5). Cancer cells were detected from 7 out of the 25 patients and 30 of the 162 cellular suspensions. The detection rate was correlated with the size and infiltrating depth of the cancer. Flow cytometry is a reliable, rapid, and quantitative method for detecting lymph node micrometastasis in colorectal cancer.

heteroHarvest: Harvesting Information from Heterogeneous Sources

DEFF Research Database (Denmark)

Qureshi, Pir Abdul Rasool; Memon, Nasrullah; Wiil, Uffe Kock

2011-01-01

The abundance of information regarding any topic makes the Internet a very good resource. Even though searching the Internet is very easy, what remains difficult is to automate the process of information extraction from the available online information due to the lack of structure and the diversity...... in the sharing methods. Most of the times, information is stored in different proprietary formats, complying with different standards and protocols which makes tasks like data mining and information harvesting very difficult. In this paper, an information harvesting tool (heteroHarvest) is presented...... with objectives to address these problems by filtering the useful information and then normalizing the information in a singular non hypertext format. Finally we describe the results of experimental evaluation. The results are found promising with an overall error rate equal to 6.5% across heterogeneous formats....

Peculiarities of the Third Natural Frequency Vibrations of a Cantilever for the Improvement of Energy Harvesting

Directory of Open Access Journals (Sweden)

Vytautas Ostasevicius

2015-05-01

Full Text Available This paper focuses on several aspects extending the dynamical efficiency of a cantilever beam vibrating in the third mode. A few ways of producing this mode stimulation, namely vibro-impact or forced excitation, as well as its application for energy harvesting devices are proposed. The paper presents numerical and experimental analyses of novel structural dynamics effects along with an optimal configuration of the cantilever beam. The peculiarities of a cantilever beam vibrating in the third mode are related to the significant increase of the level of deformations capable of extracting significant additional amounts of energy compared to the conventional harvester vibrating in the first mode. Two types of a piezoelectric vibrating energy harvester (PVEH prototype are analysed in this paper: the first one without electrode segmentation, while the second is segmented using electrode segmentation at the strain nodes of the third vibration mode to achieve effective operation at the third resonant frequency. The results of this research revealed that the voltage generated by any segment of the segmented PVEH prototype excited at the third resonant frequency demonstrated a 3.4–4.8-fold increase in comparison with the non-segmented prototype. Simultaneously, the efficiency of the energy harvester prototype also increased at lower resonant frequencies from 16% to 90%. The insights presented in the paper may serve for the development and fabrication of advanced piezoelectric energy harvesters which would be able to generate a considerably increased amount of electrical energy independently of the frequency of kinematical excitation.

A mathematical prediction model incorporating molecular subtype for risk of non-sentinel lymph node metastasis in sentinel lymph node-positive breast cancer patients: a retrospective analysis and nomogram development.

Science.gov (United States)

Wang, Na-Na; Yang, Zheng-Jun; Wang, Xue; Chen, Li-Xuan; Zhao, Hong-Meng; Cao, Wen-Feng; Zhang, Bin

2018-04-25

Molecular subtype of breast cancer is associated with sentinel lymph node status. We sought to establish a mathematical prediction model that included breast cancer molecular subtype for risk of positive non-sentinel lymph nodes in breast cancer patients with sentinel lymph node metastasis and further validate the model in a separate validation cohort. We reviewed the clinicopathologic data of breast cancer patients with sentinel lymph node metastasis who underwent axillary lymph node dissection between June 16, 2014 and November 16, 2017 at our hospital. Sentinel lymph node biopsy was performed and patients with pathologically proven sentinel lymph node metastasis underwent axillary lymph node dissection. Independent risks for non-sentinel lymph node metastasis were assessed in a training cohort by multivariate analysis and incorporated into a mathematical prediction model. The model was further validated in a separate validation cohort, and a nomogram was developed and evaluated for diagnostic performance in predicting the risk of non-sentinel lymph node metastasis. Moreover, we assessed the performance of five different models in predicting non-sentinel lymph node metastasis in training cohort. Totally, 495 cases were eligible for the study, including 291 patients in the training cohort and 204 in the validation cohort. Non-sentinel lymph node metastasis was observed in 33.3% (97/291) patients in the training cohort. The AUC of MSKCC, Tenon, MDA, Ljubljana, and Louisville models in training cohort were 0.7613, 0.7142, 0.7076, 0.7483, and 0.671, respectively. Multivariate regression analysis indicated that tumor size (OR = 1.439; 95% CI 1.025-2.021; P = 0.036), sentinel lymph node macro-metastasis versus micro-metastasis (OR = 5.063; 95% CI 1.111-23.074; P = 0.036), the number of positive sentinel lymph nodes (OR = 2.583, 95% CI 1.714-3.892; P model based on the results of multivariate analysis was established to predict the risk of non

Live and Dead Nodes

DEFF Research Database (Denmark)

Jørgensen, Sune Lehman; Jackson, A. D.

2005-01-01

In this paper, we explore the consequences of a distinction between `live' and `dead' network nodes; `live' nodes are able to acquire new links whereas `dead' nodes are static. We develop an analytically soluble growing network model incorporating this distinction and show that it can provide...

Evaluation of MR lymphography with positive lymphotropic contrast agent in diagnosing lymph node lesions

International Nuclear Information System (INIS)

Zhou Zhengyang; Yu Haiping; Chen Junkun; Zhu Bin

2010-01-01

Objective: To evaluate the interstital MR lymphography using positive lymphotropic contrast agent for differentiation of metastatic lymph nodes from inflammatory lymph nodes hyperplasm. Methods: Eighteen New Zealand white rabbits weighted at 2. 0-2. 5 kg were used. Inflammatory hyperplastic popliteal lymph node model was established in 9 rabbits by injection of complete freund adjuvant into the interdigitial skin of the dorsal aspect of one hind leg, and tumor-bearing popliteal lymph node model was established in another 9 rabbits by injection of VX2 tumor cell suspension. The popliteal lymph nodes of another hind leg of all 18 rabbits were assigned to the normal contral group. In each group, every rabbit underwent MR lymphography examination before and after the inoculation. Volumes of 0.2 ml of Gd [ DTPA-bis ( 2-aminoethoxy ) ethane ] polymeric contrast agent ( Gd-poly-DTPA-EOEA ) injection were injected subcutaneously into the dorsal feet of both hind legs of two groups of rabbits. T 1 -weighted 3D gradient-echo images were obtained, and source images were used to reconstruct images of MIP before and after the administration of agent. The maximum short-axis diameter (MSAD) of each popliteal lymph node was measured on the enhanced 3D MIP images, and the signal-to-noise ratio (SNR) measurement was performed in the largest popliteal node of each rabbit at each time point in delayed scan. Independent- samples t test was used to compare the sizes of popliteal nodes in MSADs between inflammatorily hyperplastic and tumor-bearing nodes after the inoculation, and the values of SNRs of popliteal nodes at each time point between inflammatorily hyperplastic, tumor-bearing and normal popliteal lymph nodes. Imaging results of the popliteal nodes were analyzed and correlated with pathological findings. Results: All of the rabbits were successfully inoculated except of the 2 rabbits in tumor-bearing nodal group. The size in MSAD of 13 inflammatorily hyperplastic and 11 tumor

Fabrication of Scalable Indoor Light Energy Harvester and Study for Agricultural IoT Applications

International Nuclear Information System (INIS)

Watanabe, M; Nakamura, A; Kunii, A; Kusano, K; Futagawa, M

2015-01-01

A scalable indoor light energy harvester was fabricated by microelectromechanical system (MEMS) and printing hybrid technology and evaluated for agricultural IoT applications under different environmental input power density conditions, such as outdoor farming under the sun, greenhouse farming under scattered lighting, and a plant factory under LEDs. We fabricated and evaluated a dye- sensitized-type solar cell (DSC) as a low cost and “scalable” optical harvester device. We developed a transparent conductive oxide (TCO)-less process with a honeycomb metal mesh substrate fabricated by MEMS technology. In terms of the electrical and optical properties, we achieved scalable harvester output power by cell area sizing. Second, we evaluated the dependence of the input power scalable characteristics on the input light intensity, spectrum distribution, and light inlet direction angle, because harvested environmental input power is unstable. The TiO 2 fabrication relied on nanoimprint technology, which was designed for optical optimization and fabrication, and we confirmed that the harvesters are robust to a variety of environments. Finally, we studied optical energy harvesting applications for agricultural IoT systems. These scalable indoor light harvesters could be used in many applications and situations in smart agriculture. (paper)

Fabrication of Scalable Indoor Light Energy Harvester and Study for Agricultural IoT Applications

Science.gov (United States)

Watanabe, M.; Nakamura, A.; Kunii, A.; Kusano, K.; Futagawa, M.

2015-12-01

A scalable indoor light energy harvester was fabricated by microelectromechanical system (MEMS) and printing hybrid technology and evaluated for agricultural IoT applications under different environmental input power density conditions, such as outdoor farming under the sun, greenhouse farming under scattered lighting, and a plant factory under LEDs. We fabricated and evaluated a dye- sensitized-type solar cell (DSC) as a low cost and “scalable” optical harvester device. We developed a transparent conductive oxide (TCO)-less process with a honeycomb metal mesh substrate fabricated by MEMS technology. In terms of the electrical and optical properties, we achieved scalable harvester output power by cell area sizing. Second, we evaluated the dependence of the input power scalable characteristics on the input light intensity, spectrum distribution, and light inlet direction angle, because harvested environmental input power is unstable. The TiO2 fabrication relied on nanoimprint technology, which was designed for optical optimization and fabrication, and we confirmed that the harvesters are robust to a variety of environments. Finally, we studied optical energy harvesting applications for agricultural IoT systems. These scalable indoor light harvesters could be used in many applications and situations in smart agriculture.

Effectiveness of Fibrin Sealant Patch in Reducing Drain Volume after Pelvic Lymph Node Dissection in Women with Gynecologic Malignancy

Directory of Open Access Journals (Sweden)

Hwa Cheong Kim

2017-01-01

Full Text Available Background. The goal of this study was to evaluate the effectiveness of fibrin sealant in decreasing postoperative lymphatic drainage in women after pelvic lymphadenectomy and/or para-aortic lymphadenectomy during gynecologic cancer surgery. Methods. This study is a retrospective case-control study. Forty-five patients who underwent staging surgery were enrolled. Twenty-seven patients were in the fibrin sealant group (group A and 18 in the control group (group B. The two groups were compared for the total volume of drain, hospital stay, harvested lymph node, and incidence of asymptomatic lymphocele. Lymphocele formation was evaluated by computed tomography (CT on 3 months after surgery. Results. There were no significant differences in patient demographics between group A and B with respect to age, BMI, and harvested lymph nodes. Patients who received fibrin sealants had reduced total volume of drainage from postoperative days 2 to 5 compared to the control group (group A versus group B: 994.819±745.85 ml versus 1847.89±1241.41 ml; P=0.015. However no differences were observed in hospital stay (P=0.282, duration of drain (P=0.207, and incidence of asymptomatic lymphocele at 3 months (P=0.126. Conclusion. The results of this study indicate that the application of fibrin sealants after pelvic and/or para-aortic lymphadenectomy may reduce lymphatic drainage in gynecologic malignancy.

Photovoltaic Energy Harvester with Power Management System

Directory of Open Access Journals (Sweden)

M. Ferri

2010-01-01

Full Text Available We present a photovoltaic energy harvester, realized in 0.35-μm CMOS technology. The proposed system collects light energy from the environment, by means of 2-mm2 on-chip integrated microsolar cells, and accumulates it in an external capacitor. While the capacitor is charging, the load is disconnected. When the energy in the external capacitor is enough to operate the load for a predefined time slot, the load is connected to the capacitor by a power management circuit. The choice of the value of the capacitance determines the operating time slot for the load. The proposed solution is suitable for discrete-time-regime applications, such as sensor network nodes, or, in general, systems that require power supply periodically for short time slots. The power management circuit includes a charge pump, a comparator, a level shifter, and a linear voltage regulator. The whole system has been extensively simulated, integrated, and experimentally characterized.

Accuracy of multidetector-row CT in diagnosing lymph node metastasis in patients with gastric cancer

Energy Technology Data Exchange (ETDEWEB)

Saito, Takuro; Kurokawa, Yukinori; Takiguchi, Shuji; Miyazaki, Yasuhiro; Takahashi, Tsuyoshi; Yamasaki, Makoto; Miyata, Hiroshi; Nakajima, Kiyokazu; Mori, Masaki; Doki, Yuichiro [Osaka University, Graduate School of Medicine, Department of Gastroenterological Surgery, Suita, Osaka (Japan)

2014-08-06

The purpose of this study was to determine the optimal cut-off value of lymph node size for diagnosing metastasis in gastric cancer with multidetector-row computed tomography (MDCT) after categorizing perigastric lymph nodes into three regions. The study included 90 gastric cancer patients who underwent gastrectomy. The long-axis diameter (LAD) and short-axis diameter (SAD) of all visualized lymph nodes were measured with transverse MDCT images. The locations of lymph nodes were categorized into three regions: lesser curvature, greater curvature, and suprapancreatic. The diagnostic value of lymph node metastasis was assessed with receiver operating characteristic (ROC) analysis. The area under the curve was larger for SAD than LAD in all groups. The optimal cut-off values of SAD were determined as follows: overall, 9 mm; differentiated type, 9 mm; undifferentiated type, 8 mm; lesser curvature region, 7 mm; greater curvature region, 6 mm; and suprapancreatic region, 9 mm. The diagnostic accuracies for lymph node metastasis using individual cut-off values were 71.1 % based on histological type and 76.6 % based on region of lymph node location. The diagnostic accuracy of lymph node metastasis in gastric cancer was improved by using individual cut-off values for each lymph node region. (orig.)

Adaptive Control of the Packet Transmission Period with Solar Energy Harvesting Prediction in Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Kideok Kwon

2015-04-01

Full Text Available A number of research works has studied packet scheduling policies in energy scavenging wireless sensor networks, based on the predicted amount of harvested energy. Most of them aim to achieve energy neutrality, which means that an embedded system can operate perpetually while meeting application requirements. Unlike other renewable energy sources, solar energy has the feature of distinct periodicity in the amount of harvested energy over a day. Using this feature, this paper proposes a packet transmission control policy that can enhance the network performance while keeping sensor nodes alive. Furthermore, this paper suggests a novel solar energy prediction method that exploits the relation between cloudiness and solar radiation. The experimental results and analyses show that the proposed packet transmission policy outperforms others in terms of the deadline miss rate and data throughput. Furthermore, the proposed solar energy prediction method can predict more accurately than others by 6.92%.

Adaptive control of the packet transmission period with solar energy harvesting prediction in wireless sensor networks.

Science.gov (United States)

Kwon, Kideok; Yang, Jihoon; Yoo, Younghwan

2015-04-24

A number of research works has studied packet scheduling policies in energy scavenging wireless sensor networks, based on the predicted amount of harvested energy. Most of them aim to achieve energy neutrality, which means that an embedded system can operate perpetually while meeting application requirements. Unlike other renewable energy sources, solar energy has the feature of distinct periodicity in the amount of harvested energy over a day. Using this feature, this paper proposes a packet transmission control policy that can enhance the network performance while keeping sensor nodes alive. Furthermore, this paper suggests a novel solar energy prediction method that exploits the relation between cloudiness and solar radiation. The experimental results and analyses show that the proposed packet transmission policy outperforms others in terms of the deadline miss rate and data throughput. Furthermore, the proposed solar energy prediction method can predict more accurately than others by 6.92%.

Support vector machine model for diagnosis of lymph node metastasis in gastric cancer with multidetector computed tomography: a preliminary study

Directory of Open Access Journals (Sweden)

Gao Yun

2011-01-01

Full Text Available Abstract Background Lymph node metastasis (LNM of gastric cancer is an important prognostic factor regarding long-term survival. But several imaging techniques which are commonly used in stomach cannot satisfactorily assess the gastric cancer lymph node status. They can not achieve both high sensitivity and specificity. As a kind of machine-learning methods, Support Vector Machine has the potential to solve this complex issue. Methods The institutional review board approved this retrospective study. 175 consecutive patients with gastric cancer who underwent MDCT before surgery were included. We evaluated the tumor and lymph node indicators on CT images including serosal invasion, tumor classification, tumor maximum diameter, number of lymph nodes, maximum lymph node size and lymph nodes station, which reflected the biological behavior of gastric cancer. Univariate analysis was used to analyze the relationship between the six image indicators with LNM. A SVM model was built with these indicators above as input index. The output index was that lymph node metastasis of the patient was positive or negative. It was confirmed by the surgery and histopathology. A standard machine-learning technique called k-fold cross-validation (5-fold in our study was used to train and test SVM models. We evaluated the diagnostic capability of the SVM models in lymph node metastasis with the receiver operating characteristic (ROC curves. And the radiologist classified the lymph node metastasis of patients by using maximum lymph node size on CT images as criterion. We compared the areas under ROC curves (AUC of the radiologist and SVM models. Results In 175 cases, the cases of lymph node metastasis were 134 and 41 cases were not. The six image indicators all had statistically significant differences between the LNM negative and positive groups. The means of the sensitivity, specificity and AUC of SVM models with 5-fold cross-validation were 88.5%, 78.5% and 0

Harvesting wildlife affected by climate change: a modelling and management approach for polar bears

Science.gov (United States)

Regehr, Eric V.; Wilson, Ryan R.; Rode, Karyn D.; Runge, Michael C.; Stern, Harry

2017-01-01

The conservation of many wildlife species requires understanding the demographic effects of climate change, including interactions between climate change and harvest, which can provide cultural, nutritional or economic value to humans.We present a demographic model that is based on the polar bear Ursus maritimus life cycle and includes density-dependent relationships linking vital rates to environmental carrying capacity (K). Using this model, we develop a state-dependent management framework to calculate a harvest level that (i) maintains a population above its maximum net productivity level (MNPL; the population size that produces the greatest net increment in abundance) relative to a changing K, and (ii) has a limited negative effect on population persistence.Our density-dependent relationships suggest that MNPL for polar bears occurs at approximately 0·69 (95% CI = 0·63–0·74) of K. Population growth rate at MNPL was approximately 0·82 (95% CI = 0·79–0·84) of the maximum intrinsic growth rate, suggesting relatively strong compensation for human-caused mortality.Our findings indicate that it is possible to minimize the demographic risks of harvest under climate change, including the risk that harvest will accelerate population declines driven by loss of the polar bear's sea-ice habitat. This requires that (i) the harvest rate – which could be 0 in some situations – accounts for a population's intrinsic growth rate, (ii) the harvest rate accounts for the quality of population data (e.g. lower harvest when uncertainty is large), and (iii) the harvest level is obtained by multiplying the harvest rate by an updated estimate of population size. Environmental variability, the sex and age of removed animals and risk tolerance can also affect the harvest rate.Synthesis and applications. We present a coupled modelling and management approach for wildlife that accounts for climate change and can be used to balance trade-offs among multiple

Related Drupal Nodes Block

NARCIS (Netherlands)

Van der Vegt, Wim

2010-01-01

Related Drupal Nodes Block This module exposes a block that uses Latent Semantic Analysis (Lsa) internally to suggest three nodes that are relevant to the node a user is viewing. This module performs three tasks. 1) It periodically indexes a Drupal site and generates a Lsa Term Document Matrix.

Toward a semi-mechanical harvesting platform system for harvesting blueberries with fresh-market quality

Science.gov (United States)

Major concerns related to harvesting blueberries for fresh market with over-the-row (OTR) harvesters are that the quality of the fruit harvested with OTR machines is generally low and ground loss is excessive. Machine-harvested blueberries have more internal bruise and usually soften rapidly in col...

Distributed parameter modeling to prevent charge cancellation for discrete thickness piezoelectric energy harvester

Science.gov (United States)

Krishnasamy, M.; Qian, Feng; Zuo, Lei; Lenka, T. R.

2018-03-01

The charge cancellation due to the change of strain along single continuous piezoelectric layer can remarkably affect the performance of a cantilever based harvester. In this paper, analytical models using distributed parameters are developed with some extent of averting the charge cancellation in cantilever piezoelectric transducer where the piezoelectric layers are segmented at strain nodes of concerned vibration mode. The electrode of piezoelectric segments are parallelly connected with a single external resistive load in the 1st model (Model 1). While each bimorph piezoelectric layers are connected in parallel to a resistor to form an independent circuit in the 2nd model (Model 2). The analytical expressions of the closed-form electromechanical coupling responses in frequency domain under harmonic base excitation are derived based on the Euler-Bernoulli beam assumption for both models. The developed analytical models are validated by COMSOL and experimental results. The results demonstrate that the energy harvesting performance of the developed segmented piezoelectric layer models is better than the traditional model of continuous piezoelectric layer.

Usefulness of T-Shaped Gauze for Precise Dissection of Supra-Pancreatic Lymph Nodes and for Reduced Postoperative Pancreatic Fistula in Patients Undergoing Laparoscopic Gastrectomy for Gastric Cancer.

Science.gov (United States)

Matsunaga, Tomoyuki; Saito, Hiroaki; Murakami, Yuki; Kuroda, Hirohiko; Fukumoto, Yoji; Osaki, Tomohiro

2016-09-01

Supra-pancreatic lymph node dissection is important in patients undergoing laparoscopic gastrectomy (LG) for gastric cancer. A clear view of the supra-pancreatic area is necessary for precise dissection of supra-pancreatic lymph nodes without injury to the pancreas. This retrospective study assessed the efficacy of T-shaped gauze (TSG) in retracting the pancreas during supra-pancreatic lymph node dissection. The study cohort consisted of 80 patients who underwent LG for gastric cancer. Of these, 44 patients underwent pancreatic retraction with TSG (TSG group) and 36 without TSG (non-TSG group). The efficacy of TSG for pancreatic retraction was evaluated by comparing all grade and Clavien-Dindo grade ≥ III postoperative pancreatic fistula (POPF) and the total number of dissected supra-pancreatic lymph nodes in the TSG and non-TSG groups. The rates of all grade (6.8% vs. 11%) and of Clavien-Dindo grade ≥ III (2.2% vs. 5.5%) POPF were lower in the TSG than in the non-TSG group. The total number of supra-pancreatic lymph nodes harvested by Dissection 1+ (D1+) lymph node dissection was significantly higher in TSG than in non-TSG patients ( P = 0.0078). TSG may be useful for safe and efficient performance of supra-pancreatic lymph node dissection.