Systemic Administration of Carbon Monoxide-Releasing Molecule-3 Protects the Skeletal Muscle in Porcine Model of Compartment Syndrome.

Science.gov (United States)

Bihari, Aurelia; Cepinskas, Gediminas; Sanders, David; Lawendy, Abdel-Rahman

2018-05-01

Acute limb compartment syndrome, a complication of musculoskeletal trauma, results in muscle necrosis and cell death. Carbon monoxide, liberated from the carbon monoxide-releasing molecule-3, has been shown protective in a rat model of compartment syndrome. The purpose of this study was to test the effect of carbon monoxide-releasing molecule-3 in a preclinical large animal model of compartment syndrome, with the ultimate goal of developing a pharmacologic adjunct treatment for compartment syndrome. Animal research study. Basic research laboratory in a hospital setting. Male Yorkshire-Landrace pigs (50-60 kg). Pigs underwent 6 hours of intracompartmental pressure elevation by infusing fluid into the anterior compartment of the right hind limb. Carbon monoxide-releasing molecule-3 was administered systemically (2 mg/kg, IV) at fasciotomy, followed by 3-hour reperfusion. Muscle perfusion, inflammation, injury, and apoptosis were assessed in the skeletal muscle. Systemic leukocyte activation was assessed during compartment syndrome and reperfusion. Elevation of hind limb intracompartmental pressure resulted in significant microvascular perfusion deficits (44% ± 1% continuously perfused capillaries in compartment syndrome vs 76% ± 4% in sham; p molecule-3 at fasciotomy increased the number of continuously perfused capillaries (68% ± 3%; p molecule-3 at fasciotomy offered protection against compartment syndrome-induced microvascular perfusion deficit, tissue injury, and systemic leukocyte activation. The data suggest the potential therapeutic application of carbon monoxide-releasing molecule-3 to patients at risk of developing compartment syndrome.

A review of advanced oral drug delivery technologies facilitating the protection and absorption of protein and peptide molecules.

Science.gov (United States)

Choonara, Bibi F; Choonara, Yahya E; Kumar, Pradeep; Bijukumar, Divya; du Toit, Lisa C; Pillay, Viness

2014-11-15

The oral delivery of proteins and peptides is a dynamic research field despite the numerous challenges limiting their effective delivery. Successful oral delivery of proteins and peptides requires the accomplishment of three key tasks: protection of the macromolecules from degradation in the gastrointestinal tract (GIT), permeation through the intestinal barrier and absorption of molecules into the systemic circulation. Currently, no clinically useful oral formulations have been developed but several attempts have been made to overcome the challenges of low oral bioavailability resulting from poor absorption, poor permeation and enzymatic degradation of the proteins and peptides in the GIT. Present strategies attempt to provide structural protection of the proteins and peptides and improved absorption through the use of enzyme inhibitors, absorption enhancers, novel polymeric delivery systems and chemical modification. However, each of these technologies has their limitations despite showing positive results. This review attempts to discuss the physical and chemical barriers of the GIT with particular emphasis on the current approaches employed to overcome these barriers, including the evaluation of other non-parenteral routes of protein and peptide delivery. In addition, this review assimilates oral formulation strategies under development and within the clinical trial stage in relation to their benefits and drawbacks with regard to facilitating optimal protection and absorption of proteins and peptides, as well as pertinent future challenges and opportunities governing oral drug delivery. Copyright © 2014 Elsevier Inc. All rights reserved.

Radiological protection and the Fukushima Daiichi accident. Responses of the key international organisations

Energy Technology Data Exchange (ETDEWEB)

Clement, Christopher

2017-10-01

The Fukushima Daiichi nuclear power plant accident in March 2011 shook the radiological protection world. All major organisations in the radiological protection field turned their eyes to Japan. Their actions, driven by their mandates, are reflected in their respective landmark reports on the accident. Reports of the International Commission on Radiological Protection, World Health Organisation, United Nations Scientific Committee on the Effects of Atomic Radiation, and International Atomic Energy Agency are summarised. Collaboration between key international organisations is strong, based in part on informal interactions which need to be backed up with formal relations to ensure solid long-term collaboration.

Stimulating retinal blood vessel protection with hypoxia-inducible factor stabilization: identification of novel small-molecule hydrazones to inhibit hypoxia-inducible factor prolyl hydroxylase (an American Ophthalmological Society thesis).

Science.gov (United States)

Sears, Jonathan E; Hoppe, George

2013-09-01

To discover novel small molecules that inhibit hypoxia-inducible factor (HIF) prolyl hydroxylase (PHD), a key enzyme that regulates the posttranslational stability and hence activity of HIF. NIH3T3 cell line stably transfected with firefly luciferase under a HIF-1-inducible promoter was used to screen a Chembridge library of 34,000 small molecules of molecular weight 250 to 550 Da. Positive hits were considered at 4.5-fold higher luminescence than control. Selected compounds were validated in vitro. The most effective dose was then used to treat mice expressing firefly luciferase fused to the oxygen-dependent degradation domain (lucODD) in order to determine the location of the receptor for systemic treatment with small-molecule HIF PHD inhibitors. Twenty-three novel small molecules were discovered, the majority of which were hydrazones and hydrazines. Of the 23 compounds, each had different selectivity for expression of erythropoietin or vascular endothelial growth factor, two angiogenic, HIF-regulated gene products. In addition, each showed different selectivity for hepatocytes or kidney, or both or neither, when injected intraperitoneally in an in vivo reporter gene assay. The discovery of multiple small molecules that inhibit HIF PHD identifies new reagents to develop strategies to prevent the degradation of HIF by its selective PHD. These molecules are novel hypoxia mimetics that may provide new strategies to protect retinovasculature from hyperoxia.

Multicomponent reactions provide key molecules for secret communication.

Science.gov (United States)

Boukis, Andreas C; Reiter, Kevin; Frölich, Maximiliane; Hofheinz, Dennis; Meier, Michael A R

2018-04-12

A convenient and inherently more secure communication channel for encoding messages via specifically designed molecular keys is introduced by combining advanced encryption standard cryptography with molecular steganography. The necessary molecular keys require large structural diversity, thus suggesting the application of multicomponent reactions. Herein, the Ugi four-component reaction of perfluorinated acids is utilized to establish an exemplary database consisting of 130 commercially available components. Considering all permutations, this combinatorial approach can unambiguously provide 500,000 molecular keys in only one synthetic procedure per key. The molecular keys are transferred nondigitally and concealed by either adsorption onto paper, coffee, tea or sugar as well as by dissolution in a perfume or in blood. Re-isolation and purification from these disguises is simplified by the perfluorinated sidechains of the molecular keys. High resolution tandem mass spectrometry can unequivocally determine the molecular structure and thus the identity of the key for a subsequent decryption of an encoded message.

Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

Energy Technology Data Exchange (ETDEWEB)

Kandasamy, Neelamegam; Ashokkumar, Natarajan, E-mail: npashokkumar1@gmail.com

2014-09-01

Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

International Nuclear Information System (INIS)

Kandasamy, Neelamegam; Ashokkumar, Natarajan

2014-01-01

Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

Small-molecule quinolinol inhibitor identified provides protection against BoNT/A in mice.

Directory of Open Access Journals (Sweden)

Padma Singh

Full Text Available Botulinum neurotoxins (BoNTs, etiological agents of the life threatening neuroparalytic disease botulism, are the most toxic substances currently known. The potential for the use as bioweapon makes the development of small-molecule inhibitor against these deadly toxins is a top priority. Currently, there are no approved pharmacological treatments for BoNT intoxication. Although an effective vaccine/immunotherapy is available for immuno-prophylaxis but this cannot reverse the effects of toxin inside neurons. A small-molecule pharmacological intervention, especially one that would be effective against the light chain protease, would be highly desirable. Similarity search was carried out from ChemBridge and NSC libraries to the hit (7-(phenyl(8-quinolinylaminomethyl-8-quinolinol; NSC 84096 to mine its analogs. Several hits obtained were screened for in silico inhibition using AutoDock 4.1 and 19 new molecules selected based on binding energy and Ki. Among these, eleven quinolinol derivatives potently inhibited in vitro endopeptidase activity of botulinum neurotoxin type A light chain (rBoNT/A-LC on synaptosomes isolated from rat brain which simulate the in vivo system. Five of these inhibitor molecules exhibited IC(50 values ranging from 3.0 nM to 10.0 µM. NSC 84087 is the most potent inhibitor reported so far, found to be a promising lead for therapeutic development, as it exhibits no toxicity, and is able to protect animals from pre and post challenge of botulinum neurotoxin type A (BoNT/A.

Xyloketal-derived small molecules show protective effect by decreasing mutant Huntingtin protein aggregates in Caenorhabditis elegans model of Huntington’s disease

Directory of Open Access Journals (Sweden)

Zeng YX

2016-04-01

Full Text Available Yixuan Zeng,1,2,* Wenyuan Guo,1,* Guangqing Xu,3 Qinmei Wang,4 Luyang Feng,1,2 Simei Long,1 Fengyin Liang,1 Yi Huang,1 Xilin Lu,1 Shichang Li,5 Jiebin Zhou,5 Jean-Marc Burgunder,6 Jiyan Pang,5 Zhong Pei1,2 1Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Disease, The First Affiliated Hospital, Sun Yat-sen University, 2Guangzhou Center, Chinese Huntington’s Disease Network, 3Department of Rehabilitation, The First Affiliated Hospital, 4Key laboratory on Assisted Circulation, Ministry of Health, Department of Cardiovascular Medicine of the First Affiliated Hospital, 5School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong, People’s Republic of China; 6Swiss Huntington’s Disease Center, Department of Neurology, University of Bern, Bern, Switzerland *These authors contributed equally to this work Abstract: Huntington’s disease is an autosomal-dominant neurodegenerative disorder, with chorea as the most prominent manifestation. The disease is caused by abnormal expansion of CAG codon repeats in the IT15 gene, which leads to the expression of a glutamine-rich protein named mutant Huntingtin (Htt. Because of its devastating disease burden and lack of valid treatment, development of more effective therapeutics for Huntington’s disease is urgently required. Xyloketal B, a natural product from mangrove fungus, has shown protective effects against toxicity in other neurodegenerative disease models such as Parkinson’s and Alzheimer’s diseases. To identify potential neuroprotective molecules for Huntington’s disease, six derivatives of xyloketal B were screened in a Caenorhabditis elegans Huntington’s disease model; all six compounds showed a protective effect. Molecular docking studies indicated that compound 1 could bind to residues GLN369 and GLN393 of the mutant Htt protein, forming a

Defining the Key Competencies in Radiation Protection for Endovascular Procedures: A Multispecialty Delphi Consensus Study.

Science.gov (United States)

Doyen, Bart; Maurel, Blandine; Cole, Jonathan; Maertens, Heidi; Mastracci, Tara; Van Herzeele, Isabelle

2018-02-01

Radiation protection training courses currently focus on broad knowledge topics which may not always be relevant in daily practice. The goal of this study was to determine the key competencies in radiation protection that every endovascular team member should possess and apply routinely, through multispecialty clinical content expert consensus. Consensus was obtained through a two round modified Delphi methodology. The expert panel consisted of European vascular surgeons, interventional radiologists, and interventional cardiologists/angiologists experienced in endovascular procedures. An initial list of statements, covering knowledge skills, technical skills and attitudes was created, based on a literature search. Additional statements could be suggested by the experts in the first Delphi round. Each of the statements had to be rated on a 5- point Likert scale. A statement was considered to be a key competency when the internal consistency was greater than alpha = 0.80 and at least 80% of the experts agreed (rating 4/5) or strongly agreed (rating 5/5) with the statement. Questionnaires were emailed to panel members using the Surveymonkey service. Forty-one of 65 (63.1%) invited experts agreed to participate in the study. The response rates were 36 out of 41 (87.8%): overall 38 out of 41(92.6%) in the first round and 36 out of 38 (94.7%) in the second round. The 71 primary statements were supplemented with nine items suggested by the panel. The results showed excellent consensus among responders (Cronbach's alpha = 0.937 first round; 0.958 s round). Experts achieved a consensus that 30 of 33 knowledge skills (90.9%), 23 of 27 technical skills (82.1%), and 15 of 20 attitudes (75.0%) should be considered as key competencies. A multispecialty European endovascular expert panel reached consensus about the key competencies in radiation protection. These results may serve to create practical and relevant radiation protection training courses in the future, enhancing

A Cryptographic SoC for Robust Protection of Secret Keys in IPTV DRM Systems

Science.gov (United States)

Lee, Sanghan; Yang, Hae-Yong; Yeom, Yongjin; Park, Jongsik

The security level of an internet protocol television (IPTV) digital right management (DRM) system ultimately relies on protection of secret keys. Well known devices for the key protection include smartcards and battery backup SRAMs (BB-SRAMs); however, these devices could be vulnerable to various physical attacks. In this paper, we propose a secure and cost-effective design of a cryptographic system on chip (SoC) that integrates the BB-SRAM with a cell-based design technique. The proposed SoC provides robust safeguard against the physical attacks, and satisfies high-speed and low-price requirements of IPTV set-top boxes. Our implementation results show that the maximum encryption rate of the SoC is 633Mb/s. In order to verify the data retention capabilities, we made a prototype chip using 0.18µm standard cell technology. The experimental results show that the integrated BB-SRAM can reliably retain data with a 1.4µA leakage current.

The hyaluronan and proteoglycan link proteins: Organizers of the brain extracellular matrix and key molecules for neuronal function and plasticity.

Science.gov (United States)

Oohashi, Toshitaka; Edamatsu, Midori; Bekku, Yoko; Carulli, Daniela

2015-12-01

The hyaluronan and proteoglycanbinding link protein (Hapln) is a key molecule in the formation and control of hyaluronan-based condensed perineuronal matrix in the adult brain. This review summarizes the recent advances in understanding the role of Haplns in the formation and control of two distinct types of perineuronal matrices, one for "classical" PNN and the other for the specialized extracellular matrix (ECM) at the node of Ranvier in the central nervous system (CNS). We introduce the structural components of each ECM organization including the basic concept of supramolecular structure named "HLT model". We furthermore summarize the developmental and physiological role of perineuronal ECMs from the studies of Haplns and related molecules. Finally, we also discuss the potential mechanism modulating PNNs in the adult CNS. This layer of organized matrices may exert a direct effect via core protein or sugar moiety from the structure or by acting as a binding site for biologically active molecules, which are important for neuronal plasticity and saltatory conduction. Copyright © 2015 Elsevier Inc. All rights reserved.

Molecular locks and keys: the role of small molecules in phytohormone research

Directory of Open Access Journals (Sweden)

Sandra eFonseca

2014-12-01

Full Text Available Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signalling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signalling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function.Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signalling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated responses. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds.

Role of cloned carotenoid genes expressed in Escherichia coli in protecting against inactivation by near-UV light and specific phototoxic molecules

International Nuclear Information System (INIS)

Tuveson, R.W.; Larson, R.A.; Kagan, J.

1988-01-01

Genes controlling carotenoid synthesis were cloned from Erwinia herbicola and expressed in an Escherichia coli strain. Carotenoids protect against high fluences of near-UV (NUV; 320 to 400 nm) but not against far-UV (200-300 nm). Protection of E. coli cells was not observed following treatment with either psoralen or 8-methoxypsoralen plus NUV. However, significant protection of cells producing carotenoids was observed with three photosensitizing molecules activated by NUV (alpha-terthienyl, harmine, and phenylheptatriyne) which are thought to have the membrane as an important lethal target. Protection of carotenoid-producing cells against inactivation was not observed with acridine orange plus visible light but was seen with toluidine blue O plus visible light

Stimulation of host immune defenses by a small molecule protects C. elegans from bacterial infection.

Science.gov (United States)

Pukkila-Worley, Read; Feinbaum, Rhonda; Kirienko, Natalia V; Larkins-Ford, Jonah; Conery, Annie L; Ausubel, Frederick M

2012-01-01

The nematode Caenorhabditis elegans offers currently untapped potential for carrying out high-throughput, live-animal screens of low molecular weight compound libraries to identify molecules that target a variety of cellular processes. We previously used a bacterial infection assay in C. elegans to identify 119 compounds that affect host-microbe interactions among 37,214 tested. Here we show that one of these small molecules, RPW-24, protects C. elegans from bacterial infection by stimulating the host immune response of the nematode. Using transcriptome profiling, epistasis pathway analyses with C. elegans mutants, and an RNAi screen, we show that RPW-24 promotes resistance to Pseudomonas aeruginosa infection by inducing the transcription of a remarkably small number of C. elegans genes (∼1.3% of all genes) in a manner that partially depends on the evolutionarily-conserved p38 MAP kinase pathway and the transcription factor ATF-7. These data show that the immunostimulatory activity of RPW-24 is required for its efficacy and define a novel C. elegans-based strategy to identify compounds with activity against antibiotic-resistant bacterial pathogens.

Stimulation of host immune defenses by a small molecule protects C. elegans from bacterial infection.

Directory of Open Access Journals (Sweden)

Read Pukkila-Worley

Full Text Available The nematode Caenorhabditis elegans offers currently untapped potential for carrying out high-throughput, live-animal screens of low molecular weight compound libraries to identify molecules that target a variety of cellular processes. We previously used a bacterial infection assay in C. elegans to identify 119 compounds that affect host-microbe interactions among 37,214 tested. Here we show that one of these small molecules, RPW-24, protects C. elegans from bacterial infection by stimulating the host immune response of the nematode. Using transcriptome profiling, epistasis pathway analyses with C. elegans mutants, and an RNAi screen, we show that RPW-24 promotes resistance to Pseudomonas aeruginosa infection by inducing the transcription of a remarkably small number of C. elegans genes (∼1.3% of all genes in a manner that partially depends on the evolutionarily-conserved p38 MAP kinase pathway and the transcription factor ATF-7. These data show that the immunostimulatory activity of RPW-24 is required for its efficacy and define a novel C. elegans-based strategy to identify compounds with activity against antibiotic-resistant bacterial pathogens.

Myricetin: A Dietary Molecule with Diverse Biological Activities

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Deepak Kumar Semwal

2016-02-01

Full Text Available Myricetin is a common plant-derived flavonoid and is well recognised for its nutraceuticals value. It is one of the key ingredients of various foods and beverages. The compound exhibits a wide range of activities that include strong anti-oxidant, anticancer, antidiabetic and anti-inflammatory activities. It displays several activities that are related to the central nervous system and numerous studies have suggested that the compound may be beneficial to protect against diseases such as Parkinson’s and Alzheimer’s. The use of myricetin as a preserving agent to extend the shelf life of foods containing oils and fats is attributed to the compound’s ability to protect lipids against oxidation. A detailed search of existing literature revealed that there is currently no comprehensive review available on this important molecule. Hence, the present work includes the history, synthesis, pharmaceutical applications and toxicity studies of myricetin. This report also highlights structure-activity relationships and mechanisms of action for various biological activities.

Field-free orientation of molecules

DEFF Research Database (Denmark)

Machholm, Mette; Henriksen, Niels Engholm

2001-01-01

The excitation of angular motion, in particular, the creation of a wave packet in the angular degrees of freedom via short-pulse, off-resonant excitation with respect to rotational transitions, was examined. The key result was that field-free time-dependent orientation for a molecule like LiH can...... be generated after the turn-off of a state-of-the-art electromagnetic half-cycle pulse.......The excitation of angular motion, in particular, the creation of a wave packet in the angular degrees of freedom via short-pulse, off-resonant excitation with respect to rotational transitions, was examined. The key result was that field-free time-dependent orientation for a molecule like LiH can...

Ethylene glycol monolayer protected nanoparticles: synthesis, characterization, and interactions with biological molecules.

Science.gov (United States)

Zheng, Ming; Li, Zhigang; Huang, Xueying

2004-05-11

The usefulness of the hybrid materials of nanoparticles and biological molecules on many occasions depends on how well one can achieve a rational design based on specific binding and programmable assembly. Nonspecific binding between nanoparticles and biomolecules is one of the major barriers for achieving their utilities in a biological system. In this paper, we demonstrate a new approach to eliminate nonspecific interactions between nanoparticles and biological molecules by shielding the nanoparticle with a monolayer of ethylene glycol. A direct synthesis of di-, tri-, and tetra(ethylene glycol)-protected gold nanoparticles (Au-S-EGn, n = 2, 3, and 4) was achieved under the condition that the water content was optimized in the range of 9-18% in the reaction mixture. With controlled ratio of [HAuCl4]/[EGn-SH] at 2, the synthesized particles have an average diameter of 3.5 nm and a surface plasma resonance band around 510 nm. Their surface structures were confirmed by 1H NMR spectra. These gold nanoparticles are bonded with a uniform monolayer with defined lengths of 0.8, 1.2, and 1.6 nm for Au-S-EG2, Au-S-EG3, and Au-S-EG4, respectively. They have great stabilities in aqueous solutions with a high concentration of electrolytes as well as in organic solvents. Thermogravimetric analysis revealed that the ethylene glycol monolayer coating is ca. 14% of the total nanoparticle weight. Biological binding tests by using ion-exchange chromatography and gel electrophoresis demonstrated that these Au-S-EGn (n = 2, 3, or 4) nanoparticles are free of any nonspecific bindings with various proteins, DNA, and RNA. These types of nanoparticles provide a fundamental starting material for designing hybrid materials composed of metallic nanoparticles and biomolecules.

Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

International Nuclear Information System (INIS)

Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung; Song, Jie Young; Yun, Yeon Sook

2009-01-01

The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently mutated..protein..in cancer cells. Lack of functional p53..is accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference

Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

Energy Technology Data Exchange (ETDEWEB)

Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung [PharmacoGenomics Research Center, Inje University, Busan (Korea, Republic of); Song, Jie Young; Yun, Yeon Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2009-05-15

The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently mutated..protein..in cancer cells. Lack of functional p53..is accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference.

FlavorDB: a database of flavor molecules

OpenAIRE

Garg, Neelansh; Sethupathy, Apuroop; Tuwani, Rudraksh; NK, Rakhi; Dokania, Shubham; Iyer, Arvind; Gupta, Ayushi; Agrawal, Shubhra; Singh, Navjot; Shukla, Shubham; Kathuria, Kriti; Badhwar, Rahul; Kanji, Rakesh; Jain, Anupam; Kaur, Avneet

2017-01-01

Abstract Flavor is an expression of olfactory and gustatory sensations experienced through a multitude of chemical processes triggered by molecules. Beyond their key role in defining taste and smell, flavor molecules also regulate metabolic processes with consequences to health. Such molecules present in natural sources have been an integral part of human history with limited success in attempts to create synthetic alternatives. Given their utility in various spheres of life such as food and ...

Strategies for Discovery of Small Molecule Radiation Protectors and Radiation Mitigators

Directory of Open Access Journals (Sweden)

Joel S Greenberger

2012-01-01

Full Text Available Mitochondrial targeted radiation damage protectors (delivered prior to irradiation and mitigators (delivered after irradiation, but before the appearance of symptoms associated with radiation syndrome have been a recent focus in drug discovery for 1 normal tissue radiation protection during fractionated radiotherapy, and 2 radiation terrorism counter measures. Several categories of such molecules have been discovered: nitroxide-linked hybrid molecules, including GS-nitroxide, GS-nitric oxide synthase inhibitors, p53/mdm2/mdm4 inhibitors, and pharmaceutical agents including inhibitors of the phosphoinositide-3-kinase pathway and the anti-seizure medicine, carbamazepine. Evaluation of potential new irradiation dose modifying molecules to protect normal tissue includes: clonagenic radiation survival curves; assays for apoptosis and DNA repair, and irradiation-induced depletion of antioxidant stores. Studies of organ specific radioprotection and in total body irradiation-induced hematopoietic syndrome in the mouse model for protection/mitigation facilitate rational means by which to move candidate small molecule drugs along the drug discovery pipeline into clinical development.

Strategies for Discovery of Small Molecule Radiation Protectors and Radiation Mitigators

Energy Technology Data Exchange (ETDEWEB)

Greenberger, Joel S.; Clump, David [Radiation Oncology Department, University of Pittsburgh Cancer Institute, Pittsburgh, PA (United States); Kagan, Valerian [Environmental and Occupational Health Department, University of Pittsburgh, Pittsburgh, PA (United States); Bayir, Hülya [Critical Care Medicine Department, University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Lazo, John S. [Pharmacology Department, University of Virginia, Charlottesville, VA (United States); Wipf, Peter [Department of Chemistry, Accelerated Chemical Discovery Center, University of Pittsburgh, Pittsburgh, PA (United States); Li, Song; Gao, Xiang [Pharmaceutical Science Department, University of Pittsburgh, Pittsburgh, PA (United States); Epperly, Michael W., E-mail: greenbergerjs@upmc.edu [Radiation Oncology Department, University of Pittsburgh Cancer Institute, Pittsburgh, PA (United States)

2012-01-13

Mitochondrial targeted radiation damage protectors (delivered prior to irradiation) and mitigators (delivered after irradiation, but before the appearance of symptoms associated with radiation syndrome) have been a recent focus in drug discovery for (1) normal tissue radiation protection during fractionated radiotherapy, and (2) radiation terrorism counter measures. Several categories of such molecules have been discovered: nitroxide-linked hybrid molecules, including GS-nitroxide, GS-nitric oxide synthase inhibitors, p53/mdm2/mdm4 inhibitors, and pharmaceutical agents including inhibitors of the phosphoinositide-3-kinase pathway and the anti-seizure medicine, carbamazepine. Evaluation of potential new radiation dose modifying molecules to protect normal tissue includes: clonogenic radiation survival curves, assays for apoptosis and DNA repair, and irradiation-induced depletion of antioxidant stores. Studies of organ specific radioprotection and in total body irradiation-induced hematopoietic syndrome in the mouse model for protection/mitigation facilitate rational means by which to move candidate small molecule drugs along the drug discovery pipeline into clinical development.

Endosomal recognition of Lactococcus lactis G121 and its RNA by dendritic cells is key to its allergy-protective effects.

Science.gov (United States)

Stein, Karina; Brand, Stephanie; Jenckel, André; Sigmund, Anna; Chen, Zhijian James; Kirschning, Carsten J; Kauth, Marion; Heine, Holger

2017-02-01

Bacterial cowshed isolates are allergy protective in mice; however, the underlying mechanisms are largely unknown. We examined the ability of Lactococcus lactis G121 to prevent allergic inflammatory reactions. We sought to identify the ligands and pattern recognition receptors through which L lactis G121 confers allergy protection. L lactis G121-induced cytokine release and surface expression of costimulatory molecules by untreated or inhibitor-treated (bafilomycin and cytochalasin D) human monocyte-derived dendritic cells (moDCs), bone marrow-derived mouse dendritic cells (BMDCs), and moDC/naive CD4 + T-cell cocultures were analyzed by using ELISA and flow cytometry. The pathology of ovalbumin-induced acute allergic airway inflammation after adoptive transfer of BMDCs was examined by means of microscopy. L lactis G121-treated murine BMDCs and human moDCs released T H 1-polarizing cytokines and induced T H 1 T cells. Inhibiting phagocytosis and endosomal acidification in BMDCs or moDCs impaired the release of T H 1-polarizing cytokines, costimulatory molecule expression, and T-cell activation on L lactis G121 challenge. In vivo allergy protection mediated by L lactis G121 was dependent on endosomal acidification in dendritic cells (DCs). Toll-like receptor (Tlr) 13 -/- BMDCs showed a weak response to L lactis G121 and were unresponsive to its RNA. The T H 1-polarizing activity of L lactis G121-treated human DCs was blocked by TLR8-specific inhibitors, mediated by L lactis G121 RNA, and synergistically enhanced by activation of nucleotide-binding oligomerization domain-containing protein (NOD) 2. Bacterial RNA is the main driver of L lactis G121-mediated protection against experimentally induced allergy and requires both bacterial uptake by DCs and endosomal acidification. In mice L lactis G121 RNA signals through TLR13; however, the most likely intracellular receptor in human subjects is TLR8. Copyright © 2016 American Academy of Allergy, Asthma & Immunology

Corporate Staff Social Rights and Protection as Key Points of Business Entities Social Policy

Directory of Open Access Journals (Sweden)

Svetlana V. Titova

2013-01-01

Full Text Available The article describes key notions and principles of corporate staff social rights and protection. These notions were considered in terms of business entities social policy. The author thoroughly studied such personnel rights as the right to organize and bargain collectively, freedom of association, payment for personnel labor, child labor, forced labor, duty hours, discrimination, worker safety and health. The author attaches special attention to the types of privileges and guarantees, which business entities should provide to their employees, such as compensation for moral damages caused by labor injury, material assistance to employees and their families in different cases, concerned with labor functions

Multi-Excitonic Quantum Dot Molecules

Science.gov (United States)

Scheibner, M.; Stinaff, E. A.; Doty, M. F.; Ware, M. E.; Bracker, A. S.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

2006-03-01

With the ability to create coupled pairs of quantum dots, the next step towards the realization of semiconductor based quantum information processing devices can be taken. However, so far little knowledge has been gained on these artificial molecules. Our photoluminescence experiments on single InAs/GaAs quantum dot molecules provide the systematics of coupled quantum dots by delineating the spectroscopic features of several key charge configurations in such quantum systems, including X, X^+,X^2+, XX, XX^+ (with X being the neutral exciton). We extract general rules which determine the formation of molecular states of coupled quantum dots. These include the fact that quantum dot molecules provide the possibility to realize various spin configurations and to switch the electron hole exchange interaction on and off by shifting charges inside the molecule. This knowledge will be valuable in developing implementations for quantum information processing.

Astronomers Win Protection for Key Part of Radio Spectrum

Science.gov (United States)

2000-06-01

International Telecommunication Union meet to painstakingly parcel out the radio frequency spectrum between radio-based applications such as personal communications, satellite broadcasting, GPS and amateur radio, and the sciences of radio astronomy, earth exploration and deep space research. The WRC also coordinates sharing between services in the same radio bands. WRC decisions are incorporated into the Radio Regulations that govern radio services worldwide. The new spectrum allocations for radio astronomy are the first since 1979. Millimeter-wave astronomy was then in its infancy and many of its needs were not yet known. As astronomers began to explore this region of the spectrum they found spectral lines from many interesting molecules in space. Many of those lines had not fallen into the areas originally set aside for astronomy, but most will be under the new allocations. "It's a win for millimeter-wave science," said Dr. John Whiteoak of the Australia Telescope National Facility, Australian delegate to WRC-00. "This secures its future." The protection is a significant step for both existing millimeter-wave telescopes and new ones such as the Atacama Large Millimeter Array (ALMA) now being planned by a U.S.-European consortium. Even at its isolated site in Chile's Atacama desert, ALMA would be vulnerable to interference from satellite emissions. Sensitive radio astronomy receivers are blinded by these emissions, just as an optical telescope would be by a searchlight. "There is more energy at millimeter and sub-millimeter wavelengths washing through the Universe than there is of light or any other kind of radiation," said ALMA Project Scientist, Dr. Al Wootten of the National Radio Astronomy Observatory. "Imaging the sources of this energy can tell us a great deal about the formation of stars and galaxies, and even planets." "But the Earth's atmosphere isn't very kind to us - it has only a few windows at these frequencies, and not very transparent ones at that. They are

Small-molecule kinase inhibitors: an analysis of FDA-approved drugs

DEFF Research Database (Denmark)

Wu, Peng; Nielsen, Thomas Eiland; Clausen, Mads Hartvig

2016-01-01

Small-molecule kinase inhibitors (SMKIs), 28 of which are approved by the US Food and Drug Administration (FDA), have been actively pursued as promising targeted therapeutics. Here, we assess the key structural and physicochemical properties, target selectivity and mechanism of function, and ther......Small-molecule kinase inhibitors (SMKIs), 28 of which are approved by the US Food and Drug Administration (FDA), have been actively pursued as promising targeted therapeutics. Here, we assess the key structural and physicochemical properties, target selectivity and mechanism of function...

Can radiation damage to protein crystals be reduced using small-molecule compounds?

Energy Technology Data Exchange (ETDEWEB)

Kmetko, Jan [Kenyon College, Gambier, OH 43022 (United States); Warkentin, Matthew; Englich, Ulrich; Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States); Kenyon College, Gambier, OH 43022 (United States)

2011-10-01

Free-radical scavengers that are known to be effective protectors of proteins in solution are found to increase global radiation damage to protein crystals. Protective mechanisms may become deleterious in the protein-dense environment of a crystal. Recent studies have defined a data-collection protocol and a metric that provide a robust measure of global radiation damage to protein crystals. Using this protocol and metric, 19 small-molecule compounds (introduced either by cocrystallization or soaking) were evaluated for their ability to protect lysozyme crystals from radiation damage. The compounds were selected based upon their ability to interact with radiolytic products (e.g. hydrated electrons, hydrogen, hydroxyl and perhydroxyl radicals) and/or their efficacy in protecting biological molecules from radiation damage in dilute aqueous solutions. At room temperature, 12 compounds had no effect and six had a sensitizing effect on global damage. Only one compound, sodium nitrate, appeared to extend crystal lifetimes, but not in all proteins and only by a factor of two or less. No compound provided protection at T = 100 K. Scavengers are ineffective in protecting protein crystals from global damage because a large fraction of primary X-ray-induced excitations are generated in and/or directly attack the protein and because the ratio of scavenger molecules to protein molecules is too small to provide appreciable competitive protection. The same reactivity that makes some scavengers effective radioprotectors in protein solutions may explain their sensitizing effect in the protein-dense environment of a crystal. A more productive focus for future efforts may be to identify and eliminate sensitizing compounds from crystallization solutions.

Can radiation damage to protein crystals be reduced using small-molecule compounds?

International Nuclear Information System (INIS)

Kmetko, Jan; Warkentin, Matthew; Englich, Ulrich; Thorne, Robert E.

2011-01-01

Free-radical scavengers that are known to be effective protectors of proteins in solution are found to increase global radiation damage to protein crystals. Protective mechanisms may become deleterious in the protein-dense environment of a crystal. Recent studies have defined a data-collection protocol and a metric that provide a robust measure of global radiation damage to protein crystals. Using this protocol and metric, 19 small-molecule compounds (introduced either by cocrystallization or soaking) were evaluated for their ability to protect lysozyme crystals from radiation damage. The compounds were selected based upon their ability to interact with radiolytic products (e.g. hydrated electrons, hydrogen, hydroxyl and perhydroxyl radicals) and/or their efficacy in protecting biological molecules from radiation damage in dilute aqueous solutions. At room temperature, 12 compounds had no effect and six had a sensitizing effect on global damage. Only one compound, sodium nitrate, appeared to extend crystal lifetimes, but not in all proteins and only by a factor of two or less. No compound provided protection at T = 100 K. Scavengers are ineffective in protecting protein crystals from global damage because a large fraction of primary X-ray-induced excitations are generated in and/or directly attack the protein and because the ratio of scavenger molecules to protein molecules is too small to provide appreciable competitive protection. The same reactivity that makes some scavengers effective radioprotectors in protein solutions may explain their sensitizing effect in the protein-dense environment of a crystal. A more productive focus for future efforts may be to identify and eliminate sensitizing compounds from crystallization solutions

Aging-From molecules to populations

DEFF Research Database (Denmark)

Sander, Miriam; Avlund, Kirsten; Lauritzen, Martin

2008-01-01

of human aging. To foster interactions and collaboration between diverse scientists interested in the biochemical, physiological, epidemiological and psychosocial aspects of aging, The University of Copenhagen Faculty of Health Sciences recently organized and co-sponsored a workshop entitled Aging......-From Molecules to Populations. The following questions about human aging were discussed at the workshop: What is the limit of human life expectancy? What are the key indicators of human aging? What are the key drivers of human aging? Which genes have the greatest impact on human aging? How similar is aging...

Understanding Key Mechanisms of Exercise-Induced Cardiac Protection to Mitigate Disease: Current Knowledge and Emerging Concepts.

Science.gov (United States)

Bernardo, Bianca C; Ooi, Jenny Y Y; Weeks, Kate L; Patterson, Natalie L; McMullen, Julie R

2018-01-01

The benefits of exercise on the heart are well recognized, and clinical studies have demonstrated that exercise is an intervention that can improve cardiac function in heart failure patients. This has led to significant research into understanding the key mechanisms responsible for exercise-induced cardiac protection. Here, we summarize molecular mechanisms that regulate exercise-induced cardiac myocyte growth and proliferation. We discuss in detail the effects of exercise on other cardiac cells, organelles, and systems that have received less or little attention and require further investigation. This includes cardiac excitation and contraction, mitochondrial adaptations, cellular stress responses to promote survival (heat shock response, ubiquitin-proteasome system, autophagy-lysosomal system, endoplasmic reticulum unfolded protein response, DNA damage response), extracellular matrix, inflammatory response, and organ-to-organ crosstalk. We summarize therapeutic strategies targeting known regulators of exercise-induced protection and the challenges translating findings from bench to bedside. We conclude that technological advancements that allow for in-depth profiling of the genome, transcriptome, proteome and metabolome, combined with animal and human studies, provide new opportunities for comprehensively defining the signaling and regulatory aspects of cell/organelle functions that underpin the protective properties of exercise. This is likely to lead to the identification of novel biomarkers and therapeutic targets for heart disease.

The physical and mental health of lesbian, gay male, and bisexual (LGB) older adults: the role of key health indicators and risk and protective factors.

Science.gov (United States)

Fredriksen-Goldsen, Karen I; Emlet, Charles A; Kim, Hyun-Jun; Muraco, Anna; Erosheva, Elena A; Goldsen, Jayn; Hoy-Ellis, Charles P

2013-08-01

Based on resilience theory, this paper investigates the influence of key health indicators and risk and protective factors on health outcomes (including general health, disability, and depression) among lesbian, gay male, and bisexual (LGB) older adults. A cross-sectional survey was conducted with LGB older adults, aged 50 and older (N = 2,439). Logistic regressions were conducted to examine the contributions of key health indicators (access to health care and health behaviors), risk factors (lifetime victimization, internalized stigma, and sexual identity concealment), and protective factors (social support and social network size) to health outcomes, when controlling for background characteristics. The findings revealed that lifetime victimization, financial barriers to health care, obesity, and limited physical activity independently and significantly accounted for poor general health, disability, and depression among LGB older adults. Internalized stigma was also a significant predictor of disability and depression. Social support and social network size served as protective factors, decreasing the odds of poor general health, disability, and depression. Some distinct differences by gender and sexual orientation were also observed. High levels of poor general health, disability, and depression among LGB older adults are of major concern. These findings highlight the important role of key risk and protective factors, which significantly influences health outcomes among LGB older adults. Tailored interventions must be developed to address the distinct health issues facing this historically disadvantaged population.

FlavorDB: a database of flavor molecules.

Science.gov (United States)

Garg, Neelansh; Sethupathy, Apuroop; Tuwani, Rudraksh; Nk, Rakhi; Dokania, Shubham; Iyer, Arvind; Gupta, Ayushi; Agrawal, Shubhra; Singh, Navjot; Shukla, Shubham; Kathuria, Kriti; Badhwar, Rahul; Kanji, Rakesh; Jain, Anupam; Kaur, Avneet; Nagpal, Rashmi; Bagler, Ganesh

2018-01-04

Flavor is an expression of olfactory and gustatory sensations experienced through a multitude of chemical processes triggered by molecules. Beyond their key role in defining taste and smell, flavor molecules also regulate metabolic processes with consequences to health. Such molecules present in natural sources have been an integral part of human history with limited success in attempts to create synthetic alternatives. Given their utility in various spheres of life such as food and fragrances, it is valuable to have a repository of flavor molecules, their natural sources, physicochemical properties, and sensory responses. FlavorDB (http://cosylab.iiitd.edu.in/flavordb) comprises of 25,595 flavor molecules representing an array of tastes and odors. Among these 2254 molecules are associated with 936 natural ingredients belonging to 34 categories. The dynamic, user-friendly interface of the resource facilitates exploration of flavor molecules for divergent applications: finding molecules matching a desired flavor or structure; exploring molecules of an ingredient; discovering novel food pairings; finding the molecular essence of food ingredients; associating chemical features with a flavor and more. Data-driven studies based on FlavorDB can pave the way for an improved understanding of flavor mechanisms. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Neutron protection material and neutron protection devices made of such material

International Nuclear Information System (INIS)

Ries, W.

1984-01-01

This is concerned with a neutron protection material made of thermoplastic or thermosetting plastic from high molecule hydrocarbon compounds with particularly high hydrogen and carbon contents as braking or shielding material (moderator) for fast neutrons. The plastic can contain boron for absorbing low energy neutrons. The material is used to manufacture foil, plates, pipes, shielding walls, components, bodies for radiation protection equipment, devices and plant and for neutron protection clothes. (orig./HP) [de

Enhanced Key Management Protocols for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Baojiang Cui

2015-01-01

Full Text Available With rapid development and extensive use of wireless sensor networks (WSNs, it is urgent to enhance the security for WSNs, in which key management is an effective way to protect WSNs from various attacks. However, different types of messages exchanged in WSNs typically have different security requirements which cannot be satisfied by a single keying mechanism. In this study, a basic key management protocol is described for WSNs based on four kinds of keys, which can be derived from an initial master key, and an enhanced protocol is proposed based on Diffie-Hellman algorithm. The proposed scheme restricts the adverse security impact of a captured node to the rest of WSNs and meets the requirement of energy efficiency by supporting in-network processing. The master key protection, key revocation mechanism, and the authentication mechanism based on one-way hash function are, respectively, discussed. Finally, the performance of the proposed scheme is analyzed from the aspects of computational efficiency, storage requirement and communication cost, and its antiattack capability in protecting WSNs is discussed under various attack models. In this paper, promising research directions are also discussed.

China's key role in climate protection

International Nuclear Information System (INIS)

Bach, W.; Fiebig, S.

1998-01-01

China is in the process of becoming the fourth main global player in the world economy, together with the US, the EU, and Japan. Due to an energy mix with 75% dependence on coal, a high energy intensity and low energy prices, it is, after the US, the world's second largest emitter of CO 2 . China's recoverable fossil fuel reserves have a CO 2 emission potential of some 225 Gt (the current global CO 2 emission is about 22 Gt/yr). Under a business-as-usual (BAU) scenario, all of it would be released to the atmosphere by 2040. This emission may cause a significant disruption of the climate system, resulting in severe adverse climatic and ecological impacts on China and the world. To avoid this outcome, an equitable climate-protection strategy is introduced to explore an alternative energy/climate future. Using a macroeconomic approach, it is shown that under BAU conditions, the year 2100 emissions of CO 2 will increase above 1990 levels by 370 and 96% for China and the US, respectively. In contrast, for the climate-protection conditions required by the Climate Convention, CO 2 emissions must decrease by 36% for China and by 90% for the US below 1990 levels. Using a macroeconomic-engineering approach, the total CO 2 reduction potential is found to be about 4600 Mt for 13 specific measures over a 10-yr period. The incremental costs range from US$ 0.09 to 18.55 per ton of CO 2 reduction for coal-saving stoves and solar cookers, respectively. The total reduction costs for China would be about US$ 2 billion per year or ∼ 0.4% of the 1994 GDP of China. This estimate does not allow for benefits from saved resources and avoided damages. We conclude with a discussion of various avenues for obtaining needed technological and financial support for China. (author)

An all-electric single-molecule motor.

Science.gov (United States)

Seldenthuis, Johannes S; Prins, Ferry; Thijssen, Joseph M; van der Zant, Herre S J

2010-11-23

Many types of molecular motors have been proposed and synthesized in recent years, displaying different kinds of motion, and fueled by different driving forces such as light, heat, or chemical reactions. We propose a new type of molecular motor based on electric field actuation and electric current detection of the rotational motion of a molecular dipole embedded in a three-terminal single-molecule device. The key aspect of this all-electronic design is the conjugated backbone of the molecule, which simultaneously provides the potential landscape of the rotor orientation and a real-time measure of that orientation through the modulation of the conductivity. Using quantum chemistry calculations, we show that this approach provides full control over the speed and continuity of motion, thereby combining electrical and mechanical control at the molecular level over a wide range of temperatures. Moreover, chemistry can be used to change all key parameters of the device, enabling a variety of new experiments on molecular motors.

Conserved water molecules in bacterial serine hydroxymethyltransferases.

Science.gov (United States)

Milano, Teresa; Di Salvo, Martino Luigi; Angelaccio, Sebastiana; Pascarella, Stefano

2015-10-01

Water molecules occurring in the interior of protein structures often are endowed with key structural and functional roles. We report the results of a systematic analysis of conserved water molecules in bacterial serine hydroxymethyltransferases (SHMTs). SHMTs are an important group of pyridoxal-5'-phosphate-dependent enzymes that catalyze the reversible conversion of l-serine and tetrahydropteroylglutamate to glycine and 5,10-methylenetetrahydropteroylglutamate. The approach utilized in this study relies on two programs, ProACT2 and WatCH. The first software is able to categorize water molecules in a protein crystallographic structure as buried, positioned in clefts or at the surface. The other program finds, in a set of superposed homologous proteins, water molecules that occur approximately in equivalent position in each of the considered structures. These groups of molecules are referred to as 'clusters' and represent structurally conserved water molecules. Several conserved clusters of buried or cleft water molecules were found in the set of 11 bacterial SHMTs we took into account for this work. The majority of these clusters were not described previously. Possible structural and functional roles for the conserved water molecules are envisaged. This work provides a map of the conserved water molecules helpful for deciphering SHMT mechanism and for rational design of molecular engineering experiments. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Efficient key management for cryptographically enforced access control

NARCIS (Netherlands)

Zych, Anna; Petkovic, Milan; Jonker, Willem

Cryptographic enforcement of access control mechanisms relies on encrypting protected data with the keys stored by authorized users. This approach poses the problem of the distribution of secret keys. In this paper, a key management scheme is presented where each user stores a single key and is

Functionalized molecules studied by STM: motion, switching and reactivity

International Nuclear Information System (INIS)

Grill, Leonhard

2008-01-01

Functionalized molecules represent the central issue of molecular nanotechnology. Scanning tunnelling microscopy (STM) is a powerful method to investigate such molecules, because it allows us to image them with sub-molecular resolution when adsorbed on a surface and can be used at the same time as a tool to manipulate single molecules in a controlled way. Such studies permit deep insight into the conformational, mechanical and electronic structure and thus functionalities of the molecules. In this review, recent experiments on specially designed molecules, acting as model systems for molecular nanotechnology, are reviewed. The presented studies focus on key functionalities: lateral rolling and hopping motion on a supporting surface, the switching behaviour of azobenzene derivatives by using the STM tip and the controlled reactivity of molecular side groups, which enable the formation of covalently bound molecular nanoarchitectures. (topical review)

Fluxonium-Based Artificial Molecule with a Tunable Magnetic Moment

Science.gov (United States)

Kou, A.; Smith, W. C.; Vool, U.; Brierley, R. T.; Meier, H.; Frunzio, L.; Girvin, S. M.; Glazman, L. I.; Devoret, M. H.

2017-07-01

Engineered quantum systems allow us to observe phenomena that are not easily accessible naturally. The LEGO®-like nature of superconducting circuits makes them particularly suited for building and coupling artificial atoms. Here, we introduce an artificial molecule, composed of two strongly coupled fluxonium atoms, which possesses a tunable magnetic moment. Using an applied external flux, one can tune the molecule between two regimes: one in which the ground-excited state manifold has a magnetic dipole moment and one in which the ground-excited state manifold has only a magnetic quadrupole moment. By varying the applied external flux, we find the coherence of the molecule to be limited by local flux noise. The ability to engineer and control artificial molecules paves the way for building more complex circuits for quantum simulation and protected qubits.

Social defeat promotes a reactive endothelium in a brain region-dependent manner with increased expression of key adhesion molecules, selectins and chemokines associated with the recruitment of myeloid cells to the brain.

Science.gov (United States)

Sawicki, C M; McKim, D B; Wohleb, E S; Jarrett, B L; Reader, B F; Norden, D M; Godbout, J P; Sheridan, J F

2015-08-27

Repeated social defeat (RSD) in mice causes myeloid cell trafficking to the brain that contributes to the development of prolonged anxiety-like behavior. Myeloid cell recruitment following RSD occurs in regions where neuronal and microglia activation is observed. Thus, we hypothesized that crosstalk between neurons, microglia, and endothelial cells contributes to brain myeloid cell trafficking via chemokine signaling and vascular adhesion molecules. Here we show that social defeat caused an exposure- and brain region-dependent increase in several key adhesion molecules and chemokines involved in the recruitment of myeloid cells. For example, RSD induced distinct patterns of adhesion molecule expression that may explain brain region-dependent myeloid cell trafficking. VCAM-1 and ICAM-1 mRNA expression were increased in an exposure-dependent manner. Furthermore, RSD-induced VCAM-1 and ICAM-1 protein expression were localized to the vasculature of brain regions implicated in fear and anxiety responses, which spatially corresponded to previously reported patterns of myeloid cell trafficking. Next, mRNA expression of additional adhesion molecules (E- and P-selectin, PECAM-1) and chemokines (CXCL1, CXCL2, CXCL12, CCL2) were determined in the brain. Social defeat induced an exposure-dependent increase in mRNA levels of E-selectin, CXCL1, and CXCL2 that increased with additional days of social defeat. While CXCL12 was unaffected by RSD, CCL2 expression was increased by six days of social defeat. Last, comparison between enriched CD11b(+) cells (microglia/macrophages) and enriched GLAST-1(+)/CD11b(-) cells (astrocytes) revealed RSD increased mRNA expression of IL-1β, CCL2, and CXCL2 in microglia/macrophages but not in astrocytes. Collectively, these data indicate that key mediators of leukocyte recruitment were increased in the brain vasculature following RSD in an exposure- and brain region-dependent manner. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights

A Key Management Method for Cryptographically Enforced Access Control

NARCIS (Netherlands)

Zych, Anna; Petkovic, Milan; Jonker, Willem; Fernández-Medina, Eduardo; Yagüe, Mariemma I.

Cryptographic enforcement of access control mechanisms relies on encrypting protected data with the keys stored by authorized users. This approach poses the problem of the distribution of secret keys. In this paper, a key management scheme is presented where each user stores a single key and is

Small-Molecule Binding Aptamers: Selection Strategies, Characterization, and Applications

Directory of Open Access Journals (Sweden)

Annamaria eRuscito

2016-05-01

Full Text Available Aptamers are single-stranded, synthetic oligonucleotides that fold into 3-dimensional shapes capable of binding non-covalently with high affinity and specificity to a target molecule. They are generated via an in vitro process known as the Systematic Evolution of Ligands by EXponential enrichment, from which candidates are screened and characterized, and then applied in aptamer-based biosensors for target detection. Aptamers for small molecule targets such as toxins, antibiotics, molecular markers, drugs, and heavy metals will be the focus of this review. Their accurate detection is ultimately needed for the protection and wellbeing of humans and animals. However, issues such as the drastic difference in size of the aptamer and small molecule make it challenging to select, characterize, and apply aptamers for the detection of small molecules. Thus, recent (since 2012 notable advances in small molecule aptamers, which have overcome some of these challenges, are presented here, while defining challenges that still exist are discussed

Apoptosis signaling and radiation protection

International Nuclear Information System (INIS)

Morita, Akinori; Suzuki, Norio; Hosoi, Yoshio

2005-01-01

Radiation protection by apoptosis control is the suppression of cell death in highly radiosensitive tissues. This paper describes the outline of radiation-induced apoptosis framework, apoptosis-concerned target molecules possibly related to apoptosis by radiation and their inhibitors. Although there are intrinsic (via mitochondria) and extrinsic (via death receptor) pathways in apoptosis, this review mainly mentions the former which is more important in radiation-induced apoptosis. Those molecules known at present in the apoptosis are caspase, Bcl-2 family and p53. Caspase, a group of cystein proteases, initiates apoptosis but its inhibition is known not always to result in apoptosis suppression, suggesting the existence of caspase-independent pathways. Bcl-2 family involves apoptosis-suppressing (possessing BH domains) and -promoting (lacking BH domains or possessing BH3 domain alone/BH3-only protein) groups. Two p53-transcription-dependent and one -independent pathways in p53-induced apoptosis are known and p53 can be a most possible target molecule since it positions at the start of apoptosis. Authors have found a vanadate inactivates p53. Inhibitors affecting upstream molecules of apoptosis will be the most useful candidate for apoptosis suppression/radiation protection. (S.I.) 106 refs

Chemical wiring and soldering toward all-molecule electronic circuitry.

Science.gov (United States)

Okawa, Yuji; Mandal, Swapan K; Hu, Chunping; Tateyama, Yoshitaka; Goedecker, Stefan; Tsukamoto, Shigeru; Hasegawa, Tsuyoshi; Gimzewski, James K; Aono, Masakazu

2011-06-01

Key to single-molecule electronics is connecting functional molecules to each other using conductive nanowires. This involves two issues: how to create conductive nanowires at designated positions, and how to ensure chemical bonding between the nanowires and functional molecules. Here, we present a novel method that solves both issues. Relevant functional molecules are placed on a self-assembled monolayer of diacetylene compound. A probe tip of a scanning tunneling microscope is then positioned on the molecular row of the diacetylene compound to which the functional molecule is adsorbed, and a conductive polydiacetylene nanowire is fabricated by initiating chain polymerization by stimulation with the tip. Since the front edge of chain polymerization necessarily has a reactive chemical species, the created polymer nanowire forms chemical bonding with an encountered molecular element. We name this spontaneous reaction "chemical soldering". First-principles theoretical calculations are used to investigate the structures and electronic properties of the connection. We demonstrate that two conductive polymer nanowires are connected to a single phthalocyanine molecule. A resonant tunneling diode formed by this method is discussed. © 2011 American Chemical Society

Single-photon sources based on single molecules in solids

International Nuclear Information System (INIS)

Moerner, W E

2004-01-01

Single molecules in suitable host crystals have been demonstrated to be useful single-photon emitters both at liquid-helium temperatures and at room temperature. The low-temperature source achieved controllable emission of single photons from a single terrylene molecule in p-terphenyl by an adiabatic rapid passage technique. In contrast with almost all other single-molecule systems, terrylene single molecules show extremely high photostability under continuous, high-intensity irradiation. A room-temperature source utilizing this material has been demonstrated, in which fast pumping into vibrational sidebands of the electronically excited state achieved efficient inversion of the emissive level. This source yielded a single-photon emission probability p(1) of 0.86 at a detected count rate near 300 000 photons s -1 , with very small probability of emission of more than one photon. Thus, single molecules in solids can be considered as contenders for applications of single-photon sources such as quantum key distribution

A Public-key based Information Management Model for Mobile Agents

OpenAIRE

Rodriguez, Diego; Sobrado, Igor

2000-01-01

Mobile code based computing requires development of protection schemes that allow digital signature and encryption of data collected by the agents in untrusted hosts. These algorithms could not rely on carrying encryption keys if these keys could be stolen or used to counterfeit data by hostile hosts and agents. As a consequence, both information and keys must be protected in a way that only authorized hosts, that is the host that provides information and the server that has sent the mobile a...

Molecular tilt on monolayer-protected nanoparticles

KAUST Repository

Giomi, L.

2012-02-01

The structure of the tilted phase of monolayer-protected nanoparticles is investigated by means of a simple Ginzburg-Landau model. The theory contains two dimensionless parameters representing the preferential tilt angle and the ratio ε between the energy cost due to spatial variations in the tilt of the coating molecules and that of the van der Waals interactions which favors the preferential tilt. We analyze the model for both spherical and octahedral particles. On spherical particles, we find a transition from a tilted phase, at small ε, to a phase where the molecules spontaneously align along the surface normal and tilt disappears. Octahedral particles have an additional phase at small ε characterized by the presence of six topological defects. These defective configurations provide preferred sites for the chemical functionalization of monolayer-protected nanoparticles via place-exchange reactions and their consequent linking to form molecules and bulk materials. Copyright © EPLA, 2012.

Molecular tilt on monolayer-protected nanoparticles

KAUST Repository

Giomi, L.; Bowick, M. J.; Ma, X.; Majumdar, A.

2012-01-01

The structure of the tilted phase of monolayer-protected nanoparticles is investigated by means of a simple Ginzburg-Landau model. The theory contains two dimensionless parameters representing the preferential tilt angle and the ratio ε between the energy cost due to spatial variations in the tilt of the coating molecules and that of the van der Waals interactions which favors the preferential tilt. We analyze the model for both spherical and octahedral particles. On spherical particles, we find a transition from a tilted phase, at small ε, to a phase where the molecules spontaneously align along the surface normal and tilt disappears. Octahedral particles have an additional phase at small ε characterized by the presence of six topological defects. These defective configurations provide preferred sites for the chemical functionalization of monolayer-protected nanoparticles via place-exchange reactions and their consequent linking to form molecules and bulk materials. Copyright © EPLA, 2012.

Spatial and functional restriction of regulatory molecules during mammalian myoblast fusion

International Nuclear Information System (INIS)

Pavlath, Grace K.

2010-01-01

Myoblast fusion is a highly regulated process that is key for forming skeletal muscle during development and regeneration in mammals. Much remains to be understood about the molecular regulation of myoblast fusion. Some molecules that influence mammalian muscle fusion display specific cellular localization during myogenesis. Such molecules can be localized to the contact region between two fusing cells either in both cells or only in one of the cells. How distinct localization of molecules contributes to fusion is not clear. Further complexity exists as other molecules are functionally restricted to myoblasts at later stages of myogenesis to regulate their fusion with multinucleated myotubes. This review examines these three categories of molecules and discusses how spatial and functional restriction may contribute to the formation of a multinucleated cell. Understanding how and why molecules become restricted in location or function is likely to provide further insights into the mechanisms regulating mammalian muscle fusion.

Protecting Online Transactions with Unique Embedded Key Generators

DEFF Research Database (Denmark)

Boesgaard, Martin; Zenner, Erik

2007-01-01

We present a novel approach for protecting transactions over networks. While we use the example of a netbank application, the proposal is relevant for many security-critical transactions. The approach is based on two major changes compared to current solutions. The first one is the use...... difficult. In combination, these techniques allow to build a secure channel between the client program and the server, while current solutions only build such a channel between the client computer and the server....

A Small Molecule-Screening Pipeline to Evaluate the Therapeutic Potential of 2-Aminoimidazole Molecules Against Clostridium difficile

Directory of Open Access Journals (Sweden)

Rajani Thanissery

2018-06-01

Full Text Available Antibiotics are considered to be the first line of treatment for mild to moderately severe Clostridium difficile infection (CDI in humans. However, antibiotics are also risk factors for CDI as they decrease colonization resistance against C. difficile by altering the gut microbiota and metabolome. Finding compounds that selectively inhibit different stages of the C. difficile life cycle, while sparing the indigenous gut microbiota is important for the development of alternatives to standard antibiotic treatment. 2-aminoimidazole (2-AI molecules are known to disrupt bacterial protection mechanisms in antibiotic resistant bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus, but are yet to be evaluated against C. difficile. A comprehensive small molecule-screening pipeline was developed to investigate how novel small molecules affect different stages of the C. difficile life cycle (growth, toxin, and sporulation in vitro, and a library of commensal bacteria that are associated with colonization resistance against C. difficile. The initial screening tested the efficacy of eleven 2-AI molecules (compound 1 through 11 against C. difficile R20291 compared to a vancomycin (2 μg/ml control. Molecules were selected for their ability to inhibit C. difficile growth, toxin activity, and sporulation. Further testing included growth inhibition of other C. difficile strains (CD196, M68, CF5, 630, BI9, M120 belonging to distinct PCR ribotypes, and a commensal panel (Bacteroides fragilis, B. thetaiotaomicron, C. scindens, C. hylemonae, Lactobacillus acidophilus, L. gasseri, Escherichia coli, B. longum subsp. infantis. Three molecules compound 1 and 2, and 3 were microbicidal, whereas compounds 4, 7, 9, and 11 inhibited toxin activity without affecting the growth of C. difficile strains and the commensal microbiota. The antimicrobial and anti-toxin effects of 2-AI molecules need to be further characterized for mode of

Small molecule inhibitors of anthrax edema factor.

Science.gov (United States)

Jiao, Guan-Sheng; Kim, Seongjin; Moayeri, Mahtab; Thai, April; Cregar-Hernandez, Lynne; McKasson, Linda; O'Malley, Sean; Leppla, Stephen H; Johnson, Alan T

2018-01-15

Anthrax is a highly lethal disease caused by the Gram-(+) bacteria Bacillus anthracis. Edema toxin (ET) is a major contributor to the pathogenesis of disease in humans exposed to B. anthracis. ET is a bipartite toxin composed of two proteins secreted by the vegetative bacteria, edema factor (EF) and protective antigen (PA). Our work towards identifying a small molecule inhibitor of anthrax edema factor is the subject of this letter. First we demonstrate that the small molecule probe 5'-Fluorosulfonylbenzoyl 5'-adenosine (FSBA) reacts irreversibly with EF and blocks enzymatic activity. We then show that the adenosine portion of FSBA can be replaced to provide more drug-like molecules which are up to 1000-fold more potent against EF relative to FSBA, display low cross reactivity when tested against a panel of kinases, and are nanomolar inhibitors of EF in a cell-based assay of cAMP production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Molecule Matters van der Waals Molecules - Noble Gas Clusters are London Molecules! E Arunan. Feature Article Volume 14 Issue 12 December 2009 pp 1210-1222 ...

Laser Cooled YbF Molecules for Measuring the Electron's Electric Dipole Moment

Science.gov (United States)

Lim, J.; Almond, J. R.; Trigatzis, M. A.; Devlin, J. A.; Fitch, N. J.; Sauer, B. E.; Tarbutt, M. R.; Hinds, E. A.

2018-03-01

We demonstrate one-dimensional sub-Doppler laser cooling of a beam of YbF molecules to 100 μ K . This is a key step towards a measurement of the electron's electric dipole moment using ultracold molecules. We compare the effectiveness of magnetically assisted and polarization-gradient sub-Doppler cooling mechanisms. We model the experiment and find good agreement with our data.

Study on the application of sensitizing and protective agent in the process of radiation chemistry

International Nuclear Information System (INIS)

Kamal, Z.

1976-01-01

The role of sensitizing agent and protective agent in the process of radiation chemistry is studied. Direct and indirect radiation effects on bio molecules, molecular and sensitizing agent mechanism, electron activities as the basis for sensitizing agent mechanism, protective agent mechanism on irradiated macro molecules, and kinds of protective and sensitizing agents, are discussed. (RUW)

Maximum Key Size and Classification Performance of Fuzzy Commitment for Gaussian Modeled Biometric Sources

NARCIS (Netherlands)

Kelkboom, E.J.C.; Breebaart, J.; Buhan, I.R.; Veldhuis, Raymond N.J.

Template protection techniques are used within biometric systems in order to protect the stored biometric template against privacy and security threats. A great portion of template protection techniques are based on extracting a key from, or binding a key to the binary vector derived from the

Torque Measurement at the Single Molecule Level

Science.gov (United States)

Forth, Scott; Sheinin, Maxim Y.; Inman, James; Wang, Michelle D.

2017-01-01

Methods for exerting and measuring forces on single molecules have revolutionized the study of the physics of biology. However, it is often the case that biological processes involve rotation or torque generation, and these parameters have been more difficult to access experimentally. Recent advances in the single molecule field have led to the development of techniques which add the capability of torque measurement. By combining force, displacement, torque, and rotational data, a more comprehensive description of the mechanics of a biomolecule can be achieved. In this review, we highlight a number of biological processes for which torque plays a key mechanical role. We describe the various techniques that have been developed to directly probe the torque experienced by a single molecule, and detail a variety of measurements made to date using these new technologies. We conclude by discussing a number of open questions and propose systems of study which would be well suited for analysis with torsional measurement techniques. PMID:23541162

Metal-Controlled Magnetoresistance at Room Temperature in Single-Molecule Devices.

Science.gov (United States)

Aragonès, Albert C; Aravena, Daniel; Valverde-Muñoz, Francisco J; Real, José Antonio; Sanz, Fausto; Díez-Pérez, Ismael; Ruiz, Eliseo

2017-04-26

The appropriate choice of the transition metal complex and metal surface electronic structure opens the possibility to control the spin of the charge carriers through the resulting hybrid molecule/metal spinterface in a single-molecule electrical contact at room temperature. The single-molecule conductance of a Au/molecule/Ni junction can be switched by flipping the magnetization direction of the ferromagnetic electrode. The requirements of the molecule include not just the presence of unpaired electrons: the electronic configuration of the metal center has to provide occupied or empty orbitals that strongly interact with the junction metal electrodes and that are close in energy to their Fermi levels for one of the electronic spins only. The key ingredient for the metal surface is to provide an efficient spin texture induced by the spin-orbit coupling in the topological surface states that results in an efficient spin-dependent interaction with the orbitals of the molecule. The strong magnetoresistance effect found in this kind of single-molecule wire opens a new approach for the design of room-temperature nanoscale devices based on spin-polarized currents controlled at molecular level.

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Molecule Matters van der Waals Molecules - Rg•••HF Complexes are Debye Molecules! E Arunan. Feature Article Volume 15 Issue 7 July 2010 pp 667-674. Fulltext. Click here to view fulltext PDF. Permanent link:

Lessons learned from mice deficient in lectin complement pathway molecules

DEFF Research Database (Denmark)

Genster, Ninette; Takahashi, Minoru; Sekine, Hideharu

2014-01-01

in turn activate downstream complement components, ultimately leading to elimination of the pathogen. Mice deficient in the key molecules of lectin pathway of complement have been generated in order to build knowledge of the molecular mechanisms of the lectin pathway in health and disease. Despite......The lectin pathway of the complement system is initiated when the pattern-recognition molecules, mannose-binding lectin (MBL), ficolins or collectin-11, bind to invading pathogens or damaged host cells. This leads to activation of MBL/ficolin/collectin-11 associated serine proteases (MASPs), which...... differences in the genetic arrangements of murine and human orthologues of lectin pathway molecules, the knockout mice have proven to be valuable models to explore the effect of deficiency states in humans. In addition, new insight and unexpected findings on the diverse roles of lectin pathway molecules...

The guanidinium group as a key part of water-soluble polymer carriers for siRNA complexation and protection against degradation.

Science.gov (United States)

Tabujew, Ilja; Freidel, Christoph; Krieg, Bettina; Helm, Mark; Koynov, Kaloian; Müllen, Klaus; Peneva, Kalina

2014-07-01

Here, the preparation of a novel block copolymer consisting of a statistical copolymer N-(2-hydroxypropyl) methacrylamide-s-N-(3-aminopropyl) methacrylamide and a short terminal 3-guanidinopropyl methacrylamide block is reported. This polymer structure forms neutral but water-soluble nanosized complexes with siRNA. The siRNA block copolymer complexes are first analyzed using agarose gel electrophoresis and their size is determined with fluorescence correlation spectroscopy. The protective properties of the polymer against RNA degradation are investigated by treating the siRNA block copolymer complexes with RNase V1. Heparin competition assays confirm the efficient release of the cargo in vitro. In addition, the utilization of microscale thermophoresis is demonstrated for the determination of the binding strength between a fluorescently labeled polyanion and a polymer molecule. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Watching individual molecules flex within lipid membranes using SERS

Science.gov (United States)

Taylor, Richard W.; Benz, Felix; Sigle, Daniel O.; Bowman, Richard W.; Bao, Peng; Roth, Johannes S.; Heath, George R.; Evans, Stephen D.; Baumberg, Jeremy J.

2014-08-01

Interrogating individual molecules within bio-membranes is key to deepening our understanding of biological processes essential for life. Using Raman spectroscopy to map molecular vibrations is ideal to non-destructively `fingerprint' biomolecules for dynamic information on their molecular structure, composition and conformation. Such tag-free tracking of molecules within lipid bio-membranes can directly connect structure and function. In this paper, stable co-assembly with gold nano-components in a `nanoparticle-on-mirror' geometry strongly enhances the local optical field and reduces the volume probed to a few nm3, enabling repeated measurements for many tens of minutes on the same molecules. The intense gap plasmons are assembled around model bio-membranes providing molecular identification of the diffusing lipids. Our experiments clearly evidence measurement of individual lipids flexing through telltale rapid correlated vibrational shifts and intensity fluctuations in the Raman spectrum. These track molecules that undergo bending and conformational changes within the probe volume, through their interactions with the environment. This technique allows for in situ high-speed single-molecule investigations of the molecules embedded within lipid bio-membranes. It thus offers a new way to investigate the hidden dynamics of cell membranes important to a myriad of life processes.

Protecting patches in colloidal synthesis of Au semishells

NARCIS (Netherlands)

Mann, D.; Voogt, S.; Zandvoort, R. van; Keul, H.; Möller, M.; Verheijen, M.; Nascimento-Duplat, D.; Xu, M.; Urbach, H.P.; Adam, A.J.L.; Buskens, P.

2017-01-01

Protecting groups are commonly applied in multi-step molecular syntheses to protect one or multiple functional groups from reacting. After the reaction, they are removed from the molecule. In full analogy to this concept, we report the practical and scalable colloidal synthesis of Au semishells

The specificity of targeted vaccines for APC surface molecules influences the immune response phenotype.

Directory of Open Access Journals (Sweden)

Gunnveig Grødeland

Full Text Available Different diseases require different immune responses for efficient protection. Thus, prophylactic vaccines should prime the immune system for the particular type of response needed for protection against a given infectious agent. We have here tested fusion DNA vaccines which encode proteins that bivalently target influenza hemagglutinins (HA to different surface molecules on antigen presenting cells (APC. We demonstrate that targeting to MHC class II molecules predominantly induced an antibody/Th2 response, whereas targeting to CCR1/3/5 predominantly induced a CD8(+/Th1 T cell response. With respect to antibodies, the polarizing effect was even more pronounced upon intramuscular (i.m delivery as compared to intradermal (i.d. vaccination. Despite these differences in induced immune responses, both vaccines protected against a viral challenge with influenza H1N1. Substitution of HA with ovalbumin (OVA demonstrated that polarization of immune responses, as a consequence of APC targeting specificity, could be extended to other antigens. Taken together, the results demonstrate that vaccination can be tailor-made to induce a particular phenotype of adaptive immune responses by specifically targeting different surface molecules on APCs.

Antioxidant role of glutathione S-transferases: 4-Hydroxynonenal, a key molecule in stress-mediated signaling.

Science.gov (United States)

Singhal, Sharad S; Singh, Sharda P; Singhal, Preeti; Horne, David; Singhal, Jyotsana; Awasthi, Sanjay

2015-12-15

4-Hydroxy-2-trans-nonenal (4HNE), one of the major end products of lipid peroxidation (LPO), has been shown to induce apoptosis in a variety of cell lines. It appears to modulate signaling processes in more than one way because it has been suggested to have a role in signaling for differentiation and proliferation. It has been known that glutathione S-transferases (GSTs) can reduce lipid hydroperoxides through their Se-independent glutathione-peroxidase activity and that these enzymes can also detoxify LPO end-products such as 4HNE. Available evidence from earlier studies together with results of recent studies in our laboratories strongly suggests that LPO products, particularly hydroperoxides and 4HNE, are involved in the mechanisms of stress-mediated signaling and that it can be modulated by the alpha-class GSTs through the regulation of the intracellular concentrations of 4HNE. We demonstrate that 4HNE induced apoptosis in various cell lines is accompanied with c-Jun-N-terminal kinase (JNK) and caspase-3 activation. Cells exposed to mild, transient heat or oxidative stress acquire the capacity to exclude intracellular 4HNE at a faster rate by inducing GSTA4-4 which conjugates 4HNE to glutathione (GSH), and RLIP76 which mediates the ATP-dependent transport of the GSH-conjugate of 4HNE (GS-HNE). The balance between formation and exclusion promotes different cellular processes - higher concentrations of 4HNE promote apoptosis; whereas, lower concentrations promote proliferation. In this article, we provide a brief summary of the cellular effects of 4HNE, followed by a review of its GST-catalyzed detoxification, with an emphasis on the structural attributes that play an important role in the interactions with alpha-class GSTA4-4. Taken together, 4HNE is a key signaling molecule and that GSTs being determinants of its intracellular concentrations, can regulate stress-mediated signaling, are reviewed in this article. Copyright © 2015 Elsevier Inc. All rights

Adhesion of Model Molecules to Metallic Surfaces, the Implications for Corrosion Protection

International Nuclear Information System (INIS)

De Wit, J. H. W.; Van den Brand, J.; De Wit, F. M.; Mol, J. M. C.

2008-01-01

The majority of the described experimental results deal with relatively pure aluminium. Variations were made in the pretreatment of the aluminum substrates and an investigation was performed on the resulting changes in oxide layer composition and chemistry. Subsequently, the bonding behavior of the surfaces was investigated by using model adhesion molecules. These molecules were chosen to represent the bonding functionality of an organic polymer. They were applied onto the pretreated surfaces as a monolayer and the bonding behavior was studied using infrared reflection absorption spectroscopy. A direct and clear relation was found between the hydroxyl fraction on the oxide surfaces and the amount of molecules that subsequently bonded to the surface. Moreover, it was found that most bonds between the oxide surface and organic functional groups are not stable in the presence of water. The best performance was obtained using molecules, which are capable of chemisorption with the oxide surface. Finally, it was found that freshly prepared relatively pure aluminum substrates, which are left in air, rapidly lose their bonding capacity towards organic functional groups. This can be attributed to the adsorption of contamination and water to the oxide surface. in addition the adhesion of a typical epoxy-coated aluminum system was investigated during exposure to water at different temperatures. The coating was found to quite rapidly lose its adhesion upon exposure to water. This rapid loss of adhesion corresponds well with the data where it was demonstrated that the studied epoxy coating only bonds through physisorptive hydrogen bonding, these bonds not being stable in the presence of water. After the initial loss the adhesion of the coating was however found to recover again and even exceeded the adhesion prior to exposure. The improvement could be ascribed to the growth of a thin oxyhydroxide layer on the aluminum substrate, which forms a new, water-stable and stronger bond

Magnetic field modification of ultracold molecule-molecule collisions

International Nuclear Information System (INIS)

Tscherbul, T V; Suleimanov, Yu V; Aquilanti, V; Krems, R V

2009-01-01

We present an accurate quantum mechanical study of molecule-molecule collisions in the presence of a magnetic field. The work focuses on the analysis of elastic scattering and spin relaxation in collisions of O 2 ( 3 Σ g - ) molecules at cold (∼0.1 K) and ultracold (∼10 -6 K) temperatures. Our calculations show that magnetic spin relaxation in molecule-molecule collisions is extremely efficient except at magnetic fields below 1 mT. The rate constant for spin relaxation at T=0.1 K and a magnetic field of 0.1 T is found to be as large as 6.1x10 -11 cm -3 s -1 . The magnetic field dependence of elastic and inelastic scattering cross sections at ultracold temperatures is dominated by a manifold of Feshbach resonances with the density of ∼100 resonances per Tesla for collisions of molecules in the absolute ground state. This suggests that the scattering length of ultracold molecules in the absolute ground state can be effectively tuned in a very wide range of magnetic fields. Our calculations demonstrate that the number and properties of the magnetic Feshbach resonances are dramatically different for molecules in the absolute ground and excited spin states. The density of Feshbach resonances for molecule-molecule scattering in the low-field-seeking Zeeman state is reduced by a factor of 10.

On the Security of a Simple Three-Party Key Exchange Protocol without Server’s Public Keys

Directory of Open Access Journals (Sweden)

Junghyun Nam

2014-01-01

Full Text Available Authenticated key exchange protocols are of fundamental importance in securing communications and are now extensively deployed for use in various real-world network applications. In this work, we reveal major previously unpublished security vulnerabilities in the password-based authenticated three-party key exchange protocol according to Lee and Hwang (2010: (1 the Lee-Hwang protocol is susceptible to a man-in-the-middle attack and thus fails to achieve implicit key authentication; (2 the protocol cannot protect clients’ passwords against an offline dictionary attack; and (3 the indistinguishability-based security of the protocol can be easily broken even in the presence of a passive adversary. We also propose an improved password-based authenticated three-party key exchange protocol that addresses the security vulnerabilities identified in the Lee-Hwang protocol.

Proteinaceous molecules mediating Bifidobacterium-host interactions

Directory of Open Access Journals (Sweden)

Lorena Ruiz

2016-08-01

Full Text Available Bifidobacteria are commensal microoganisms found in the gastrointestinal tract.Several strains have been attributed beneficial traits at local and systemic levels, through pathogen exclusion or immune modulation, among other benefits. This has promoted a growing industrial and scientific interest in bifidobacteria as probiotic supplements. However, the molecular mechanisms mediating this cross-talk with the human host remain unknown. High-throughput technologies, from functional genomics to transcriptomics, proteomics and interactomics coupled to the development of both in vitro and in vivo models to study the dynamics of the intestinal microbiota and their effects on host cells, have eased the identification of key molecules in these interactions. Numerous secreted or surface-associated proteins or peptides have been identified as potential mediators of bifidobacteria-host interactions and molecular cross-talk, directly participating in sensing environmental factors, promoting intestinal colonization or mediating a dialogue with mucosa-associated immune cells. On the other hand, bifidobacteria induce the production of proteins in the intestine, by epithelial or immune cells, and other gut bacteria, which are key elements in orchestrating interactions among bifidobacteria, gut microbiota and host cells. This review aims to give a comprehensive overview on proteinaceous molecules described and characterized to date, as mediators of the dynamic interplay between bifidobacteria and the human host, providing a framework to identify knowledge gaps and future research needs.

Strain-induced formation of fourfold symmetric SiGe quantum dot molecules.

Science.gov (United States)

Zinovyev, V A; Dvurechenskii, A V; Kuchinskaya, P A; Armbrister, V A

2013-12-27

The strain field distribution at the surface of a multilayer structure with disklike SiGe nanomounds formed by heteroepitaxy is exploited to arrange the symmetric quantum dot molecules typically consisting of four elongated quantum dots ordered along the [010] and [100] directions. The morphological transition from fourfold quantum dot molecules to continuous fortresslike quantum rings with an increasing amount of deposited Ge is revealed. We examine key mechanisms underlying the formation of lateral quantum dot molecules by using scanning tunneling microscopy and numerical calculations of the strain energy distribution on the top of disklike SiGe nanomounds. Experimental data are well described by a simple thermodynamic model based on the accurate evaluation of the strain dependent part of the surface chemical potential. The spatial arrangement of quantum dots inside molecules is attributed to the effect of elastic property anisotropy.

Detecting high-density ultracold molecules using atom–molecule collision

International Nuclear Information System (INIS)

Chen, Jun-Ren; Kao, Cheng-Yang; Chen, Hung-Bin; Liu, Yi-Wei

2013-01-01

Utilizing single-photon photoassociation, we have achieved ultracold rubidium molecules with a high number density that provides a new efficient approach toward molecular quantum degeneracy. A new detection mechanism for ultracold molecules utilizing inelastic atom–molecule collision is demonstrated. The resonant coupling effect on the formation of the X 1 Σ + g ground state 85 Rb 2 allows for a sufficient number of more deeply bound ultracold molecules, which induced an additional trap loss and heating of the co-existing atoms owing to the inelastic atom–molecule collision. Therefore, after the photoassociation process, the ultracold molecules can be investigated using the absorption image of the ultracold rubidium atoms mixed with the molecules in a crossed optical dipole trap. The existence of the ultracold molecules was then verified, and the amount of accumulated molecules was measured. This method detects the final produced ultracold molecules, and hence is distinct from the conventional trap loss experiment, which is used to study the association resonance. It is composed of measurements of the time evolution of an atomic cloud and a decay model, by which the number density of the ultracold 85 Rb 2 molecules in the optical trap was estimated to be >5.2 × 10 11 cm −3 . (paper)

Public key infrastructure building trusted applications and web services

CERN Document Server

Vacca, John R

2004-01-01

OVERVIEW OF PKI TECHNOLOGYPublic Key Infrastructures (PKIs): What Are They?Type of Certificate Authorities (CAS) ServicesPKI StandardsTypes of Vendor and Third-Party CA SystemsProtecting Private KeysCA System AttacksStolen Private Keys: What Can Be Done?Certificate Practice StatementsPKI ReadinessANALYZING AND DESIGNING PUBLIC KEY INFRASTRUCTURESPKI Design IssuesCost Justification and ConsiderationPKI Standards Design IssuesPKI Architectural Design ConsiderationsIMPLEMENTING PKIRequirementsImplementation ScheduleImplementation CostsPKI PerformanceMANAGING PKIRequesting a CertificateObtaining a

Secret-key expansion from covert communication

Science.gov (United States)

Arrazola, Juan Miguel; Amiri, Ryan

2018-02-01

Covert communication allows the transmission of messages in such a way that it is not possible for adversaries to detect that the communication is occurring. This provides protection in situations where knowledge that two parties are talking to each other may be incriminating to them. In this work, we study how covert communication can be used for a different purpose: secret key expansion. First, we show that any message transmitted in a secure covert protocol is also secret and therefore unknown to an adversary. We then propose a covert communication protocol where the amount of key consumed in the protocol is smaller than the transmitted key, thus leading to secure secret key expansion. We derive precise conditions for secret key expansion to occur, showing that it is possible when there are sufficiently low levels of noise for a given security level. We conclude by examining how secret key expansion from covert communication can be performed in a computational security model.

Protection of adult rat cardiac myocytes from ischemic cell death: role of caveolar microdomains and delta-opioid receptors.

Science.gov (United States)

Patel, Hemal H; Head, Brian P; Petersen, Heidi N; Niesman, Ingrid R; Huang, Diane; Gross, Garrett J; Insel, Paul A; Roth, David M

2006-07-01

The role of caveolae, membrane microenvironments enriched in signaling molecules, in myocardial ischemia is poorly defined. In the current study, we used cardiac myocytes prepared from adult rats to test the hypothesis that opioid receptors (OR), which are capable of producing cardiac protection in vivo, promote cardiac protection in cardiac myocytes in a caveolae-dependent manner. We determined protein expression and localization of delta-OR (DOR) using coimmunohistochemistry, caveolar fractionation, and immunoprecipitations. DOR colocalized in fractions with caveolin-3 (Cav-3), a structural component of caveolae in muscle cells, and could be immunoprecipitated by a Cav-3 antibody. Immunohistochemistry confirmed plasma membrane colocalization of DOR with Cav-3. Cardiac myocytes were subjected to simulated ischemia (2 h) or an ischemic preconditioning (IPC) protocol (10 min ischemia, 30 min recovery, 2 h ischemia) in the presence and absence of methyl-beta-cyclodextrin (MbetaCD, 2 mM), which binds cholesterol and disrupts caveolae. We also assessed the cardiac protective effects of SNC-121 (SNC), a selective DOR agonist, on cardiac myocytes with or without MbetaCD and MbetaCD preloaded with cholesterol. Ischemia, simulated by mineral oil layering to inhibit gas exchange, promoted cardiac myocyte cell death (trypan blue staining), a response blunted by SNC (37 +/- 3 vs. 59 +/- 3% dead cells in the presence and absence of 1 muM SNC, respectively, P protective effects of IPC or SNC, resulting in cell death comparable to that of the ischemic group. By contrast, SNC-induced protection was not abrogated in cells incubated with cholesterol-saturated MbetaCD, which maintained caveolae structure and function. These findings suggest a key role for caveolae, perhaps through enrichment of signaling molecules, in contributing to protection of cardiac myocytes from ischemic damage.

Theory of Feshbach molecule formation in a dilute gas during a magnetic field ramp

DEFF Research Database (Denmark)

Williams, J. E.; Nygaard, Nicolai; Clark, C. W.

2006-01-01

Starting with coupled atom-molecule Boltzmann equations, we develop a simplified model to understand molecule formation observed in recent experiments. Our theory predicts several key features: (1) the effective adiabatic rate constant is proportional to density; (2) in an adiabatic ramp...... show qualitative agreement with the data from [Hodby et al, Phys. Rev. Lett. 94, 120402 (2005)] without the use of adjustable parameters....

Location-Aware Dynamic Session-Key Management for Grid-Based Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

I-Hsien Lin

2010-08-01

Full Text Available Security is a critical issue for sensor networks used in hostile environments. When wireless sensor nodes in a wireless sensor network are distributed in an insecure hostile environment, the sensor nodes must be protected: a secret key must be used to protect the nodes transmitting messages. If the nodes are not protected and become compromised, many types of attacks against the network may result. Such is the case with existing schemes, which are vulnerable to attacks because they mostly provide a hop-by-hop paradigm, which is insufficient to defend against known attacks. We propose a location-aware dynamic session-key management protocol for grid-based wireless sensor networks. The proposed protocol improves the security of a secret key. The proposed scheme also includes a key that is dynamically updated. This dynamic update can lower the probability of the key being guessed correctly. Thus currently known attacks can be defended. By utilizing the local information, the proposed scheme can also limit the flooding region in order to reduce the energy that is consumed in discovering routing paths.

X-ray Diffraction from Isolated and Strongly Aligned Gas-Phase Molecules with a Free-Electron Laser

DEFF Research Database (Denmark)

Küpper, Jochen; Stern, Stephan; Holmegaard, Lotte

2014-01-01

We report experimental results on x-ray diffraction of quantum-state-selected and strongly aligned ensembles of the prototypical asymmetric rotor molecule 2,5-diiodobenzonitrile using the Linac Coherent Light Source. The experiments demonstrate first steps toward a new approach to diffractive...... imaging of distinct structures of individual, isolated gas-phase molecules. We confirm several key ingredients of single molecule diffraction experiments: the abilities to detect and count individual scattered x-ray photons in single shot diffraction data, to deliver state-selected, e. g., structural......-isomer-selected, ensembles of molecules to the x-ray interaction volume, and to strongly align the scattering molecules. Our approach, using ultrashort x-ray pulses, is suitable to study ultrafast dynamics of isolated molecules....

Single-Molecule Rotational Switch on a Dangling Bond Dimer Bearing.

Science.gov (United States)

Godlewski, Szymon; Kawai, Hiroyo; Kolmer, Marek; Zuzak, Rafał; Echavarren, Antonio M; Joachim, Christian; Szymonski, Marek; Saeys, Mark

2016-09-27

One of the key challenges in the construction of atomic-scale circuits and molecular machines is to design molecular rotors and switches by controlling the linear or rotational movement of a molecule while preserving its intrinsic electronic properties. Here, we demonstrate both the continuous rotational switching and the controlled step-by-step single switching of a trinaphthylene molecule adsorbed on a dangling bond dimer created on a hydrogen-passivated Ge(001):H surface. The molecular switch is on-surface assembled when the covalent bonds between the molecule and the dangling bond dimer are controllably broken, and the molecule is attached to the dimer by long-range van der Waals interactions. In this configuration, the molecule retains its intrinsic electronic properties, as confirmed by combined scanning tunneling microscopy/spectroscopy (STM/STS) measurements, density functional theory calculations, and advanced STM image calculations. Continuous switching of the molecule is initiated by vibronic excitations when the electrons are tunneling through the lowest unoccupied molecular orbital state of the molecule. The switching path is a combination of a sliding and rotation motion over the dangling bond dimer pivot. By carefully selecting the STM conditions, control over discrete single switching events is also achieved. Combined with the ability to create dangling bond dimers with atomic precision, the controlled rotational molecular switch is expected to be a crucial building block for more complex surface atomic-scale devices.

Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

Energy Technology Data Exchange (ETDEWEB)

Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan [University of Duisburg-Essen, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Nalbant, Perihan [University of Duisburg-Essen, Faculty of Biology, Institute of Molecular Cell Biology (Germany); Buer, Jan; Knuschke, Torben; Westendorf, Astrid M. [University Hospital Essen, University of Duisburg-Essen, Institute of Medical Microbiology (Germany); Epple, Matthias, E-mail: matthias.epple@uni-due.de [University of Duisburg-Essen, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)

2012-06-15

The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100-250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

Science.gov (United States)

Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan; Nalbant, Perihan; Buer, Jan; Knuschke, Torben; Westendorf, Astrid M.; Epple, Matthias

2012-06-01

The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100-250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

International Nuclear Information System (INIS)

Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan; Nalbant, Perihan; Buer, Jan; Knuschke, Torben; Westendorf, Astrid M.; Epple, Matthias

2012-01-01

The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100–250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

Dynamic Session-Key Generation for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Chen Chin-Ling

2008-01-01

Full Text Available Abstract Recently, wireless sensor networks have been used extensively in different domains. For example, if the wireless sensor node of a wireless sensor network is distributed in an insecure area, a secret key must be used to protect the transmission between the sensor nodes. Most of the existing methods consist of preselecting keys from a key pool and forming a key chain. Then, the sensor nodes make use of the key chain to encrypt the data. However, while the secret key is being transmitted, it can easily be exposed during transmission. We propose a dynamic key management protocol, which can improve the security of the key juxtaposed to existing methods. Additionally, the dynamic update of the key can lower the probability of the key to being guessed correctly. In addition, with the new protocol, attacks on the wireless sensor network can be avoided.

Dynamic Session-Key Generation for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Cheng-Ta Li

2008-09-01

Full Text Available Recently, wireless sensor networks have been used extensively in different domains. For example, if the wireless sensor node of a wireless sensor network is distributed in an insecure area, a secret key must be used to protect the transmission between the sensor nodes. Most of the existing methods consist of preselecting m keys from a key pool and forming a key chain. Then, the sensor nodes make use of the key chain to encrypt the data. However, while the secret key is being transmitted, it can easily be exposed during transmission. We propose a dynamic key management protocol, which can improve the security of the key juxtaposed to existing methods. Additionally, the dynamic update of the key can lower the probability of the key to being guessed correctly. In addition, with the new protocol, attacks on the wireless sensor network can be avoided.

Co-delivery of a growth factor and a tissue-protective molecule using elastin biopolymers accelerates wound healing in diabetic mice.

Science.gov (United States)

Devalliere, Julie; Dooley, Kevin; Hu, Yong; Kelangi, Sarah S; Uygun, Basak E; Yarmush, Martin L

2017-10-01

Growth factor therapy is a promising approach for chronic diabetic wounds, but strategies to efficiently and cost-effectively deliver active molecules to the highly proteolytic wound environment remain as major obstacles. Here, we re-engineered keratinocyte growth factor (KGF) and the cellular protective peptide ARA290 into a protein polymer suspension with the purpose of increasing their proteolytic resistance, thus their activity in vivo. KGF and ARA290 were fused with elastin-like peptide (ELP), a protein polymer derived from tropoelastin, that confers the ability to separate into a colloidal suspension of liquid-like coacervates. ELP fusion did not diminish peptides activities as demonstrated by ability of KGF-ELP to accelerate keratinocyte proliferation and migration, and ARA290-ELP to protect cells from apoptosis. We examined the healing effect of ARA290-ELP and KGF-ELP alone or in combination, in a full-thickness diabetic wound model. In this model, ARA290-ELP was found to accelerate healing, notably by increasing angiogenesis in the wound bed. We further showed that co-delivery of ARA290 and KGF, with the 1:4 KGF-ELP to ARA290-ELP ratio, was the most effective wound treatment with the fastest healing rate, the thicker granulation tissue and regenerated epidermis after 28 days. Overall, this study shows that ARA290-ELP and KGF-ELP constitute promising new therapeutics for treatment of chronic wounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

From Artificial Atoms to Nanocrystal Molecules: Preparation and Properties of More Complex Nanostructures

Energy Technology Data Exchange (ETDEWEB)

Choi, Charina L; Alivisatos, A Paul

2009-10-20

Quantum dots, which have found widespread use in fields such as biomedicine, photovoltaics, and electronics, are often called artificial atoms due to their size-dependent physical properties. Here this analogy is extended to consider artificial nanocrystal molecules, formed from well-defined groupings of plasmonically or electronically coupled single nanocrystals. Just as a hydrogen molecule has properties distinct from two uncoupled hydrogen atoms, a key feature of nanocrystal molecules is that they exhibit properties altered from those of the component nanoparticles due to coupling. The nature of the coupling between nanocrystal atoms and its response to vibrations and deformations of the nanocrystal molecule bonds are of particular interest. We discuss synthetic approaches, predicted and observed physical properties, and prospects and challenges toward this new class of materials.

Reduced and oxidised scytonemin: theoretical protocol for Raman spectroscopic identification of potential key biomolecules for astrobiology.

Science.gov (United States)

Varnali, Tereza; Edwards, Howell G M

2014-01-03

Scytonemin is an important UV-radiation protective biomolecule synthesised by extremophilic cyanobacteria in stressed terrestrial environments. Scytonemin and its reduced form have been both isolated experimentally and the Raman spectrum for scytonemin has been assigned and characterised experimentally both in extracts and in living extremophilic cyanobacterial colonies. Scytonemin is recognised as a key biomarker molecule for terrestrial organisms in stressed environments. We propose a new, theoretically plausible structure for oxidised scytonemin which has not been mentioned in the literature hitherto. DFT calculations for scytonemin, reduced scytonemin and the new structure modelled and proposed for oxidised scytonemin are reported along with their Raman spectroscopic data and λmax UV-absorption data obtained theoretically. Comparison of the vibrational spectroscopic assignments allows the three forms of scytonemin to be detected and identified and assist not only in the clarification of the major features in the experimentally observed Raman spectral data for the parent scytonemin but also support a protocol proposed for their analytical discrimination. The results of this study provide a basis for the search for molecules of this type in future astrobiological missions of exploration and the search for extinct and extant life terrestrially. Copyright © 2013 Elsevier B.V. All rights reserved.

Cycloxygenase-2(cox-2) - a potential target for screening of small molecules as radiation countermeasure agents: an in silico study

International Nuclear Information System (INIS)

Joshi, Jayadev; Shrivastava, Nitisha; Dimri, Manali; Ghosh, Subhajit; Mandal, Rahul Shubhra; Prem Kumar, I.; Barik, Tapan Kumar

2012-01-01

COX-2 is well established for its role in inflammation and cancer, and has also been reported to play a significant role in radiation induced inflammation and by standard effect. It's already reported to have a role in protection against radiation induced damage suggesting it to be an important target for identifying novel radiation countermeasure agents. Present study aims at identifying novel small molecules from pharmacopoeia using COX-2 as target in-silico. Systematic search of the reported molecules exhibiting radiation protection revealed lat around 29 % (40 in 138) of them have a role in inflammation and a small percentage of these molecules (20 %; 8 in 40) are reported to as non steroidal anti-inflammatory drugs (NSAIDS). Docking studies performed further clarified that all these 8 radioprotective molecules shows high binding affinity and inhibit COX-2. Further Johns Hopkins clinical compound library (JHCCL), a collection of small molecule clinical compounds, were screened virtually for COX-2 inhibition by docking approach. Docking of around 1400 small molecules against COX-2 lead to identification of a number of previously unreported molecules which are likely to act as radioprotectors. (author)

Cycloxygenase-2(cox-2) - a potential target for screening of small molecules as radiation countermeasure agents: an in silico study

Energy Technology Data Exchange (ETDEWEB)

Joshi, Jayadev; Shrivastava, Nitisha; Dimri, Manali; Ghosh, Subhajit; Mandal, Rahul Shubhra; Prem Kumar, I., E-mail: prem_indra@yahoo.co.in [Radiation Biosciences Division, Institute of Nuclear Medicine and Allied Sciences, Delhi (India); Barik, Tapan Kumar [P.G. Department of Zoology, Berhampur University, Berhampur (India)

2012-07-01

COX-2 is well established for its role in inflammation and cancer, and has also been reported to play a significant role in radiation induced inflammation and by standard effect. It's already reported to have a role in protection against radiation induced damage suggesting it to be an important target for identifying novel radiation countermeasure agents. Present study aims at identifying novel small molecules from pharmacopoeia using COX-2 as target in-silico. Systematic search of the reported molecules exhibiting radiation protection revealed lat around 29 % (40 in 138) of them have a role in inflammation and a small percentage of these molecules (20 %; 8 in 40) are reported to as non steroidal anti-inflammatory drugs (NSAIDS). Docking studies performed further clarified that all these 8 radioprotective molecules shows high binding affinity and inhibit COX-2. Further Johns Hopkins clinical compound library (JHCCL), a collection of small molecule clinical compounds, were screened virtually for COX-2 inhibition by docking approach. Docking of around 1400 small molecules against COX-2 lead to identification of a number of previously unreported molecules which are likely to act as radioprotectors. (author)

Growing interstellar molecules with ion-molecule reactions

International Nuclear Information System (INIS)

Bohme, D.K.

1989-01-01

Laboratory measurements of gas-phase ion-molecule reactions continue to provide important insights into the chemistry of molecular growth in interstellar environments. It is also true that the measurements are becoming more demanding as larger molecules capture our interest. While some of these measurements are motivated by current developments in chemical models of interstellar environments or by new molecular observations by astronomers, others explore novel chemistry which can lead to predictions of new interstellar molecules. Here the author views the results of some recent measurements, taken in the Ion Chemistry Laboratory at York University with the SIFT technique, which address some of the current needs of modellers and observers and which also provide some new fundamental insight into molecular growth, particularly when it occurs in the presence of large molecules such as PAH molecules which are now thought to have a major influence on the chemistry of interstellar environments in which they are present

Nitric oxide is a key molecule in migraine and other vascular headaches

DEFF Research Database (Denmark)

Olesen, J; Thomsen, L L; Iversen, Helle Klingenberg

1994-01-01

Nitric oxide (NO) may play a key role in migraine and other vascular headaches since glyceryl trinitrate (a donor of NO) and histamine (which probably activates endothelial NO formation) both cause a pulsating dose-dependent headache with several migrainous characteristics. At relatively high doses...... Olesen, Lars Thomsen and Helle Iversen suggest that migraine may be caused by increased amounts and/or affinity of an enzyme in the NO-triggered cascade of reactions. NO may also be involved in the pathogenesis of other vascular headaches....

IAEA Patient Protection Effort Reaches Key Milestone

International Nuclear Information System (INIS)

2012-01-01

Full text: An International Atomic Energy Agency (IAEA) effort to help people track their radiation exposure from medical procedures achieved a significant milestone this week. The Agency received the final approval from a group of medical oversight organizations for the 'Joint Position Statement on the IAEA Patient Radiation Exposure Tracking', a set of principles to guide patient protection efforts at the sub-national, national, and international level. The joint statement endorses the IAEA's three-year-old Smart Card/SmartRadTrack project, which aims to help nations develop systems to track medical radiation procedures and radiation doses. The statement has been agreed by the World Health Organization (WHO), the U.S. Food and Drug Administration (FDA), the European Society of Radiology (ESR), the International Organization for Medical Physics (IOMP), the International Society of Radiographers and Radiological Technologists (ISRRT), and the Conference of Radiation Control Program Directors, USA (CRCPD). 'This system is critical if the medical community is going to keep patients safe when they are being referred for more and more diagnostic scans. These scans, over the years, are made using more and more powerful machines', said Madan Rehani, Radiation Safety Specialist in the IAEA's Radiation Protection of Patients Unit. 'The tracking system will draw doctors' attention to previous radiological examinations, both in terms of clinical information and radiation dose and thus help them assess whether the 11th or 20th CT scan is really appropriate, whether it will do more good than harm.' Advances in radiation-based diagnostic technologies, such as the CT scan, have led to patients receiving such procedures more frequently. The convenience of CT with the added advantage of increased information has resulted in increased usage to the point that there are instances of patients getting tens of CT scans in a few years, not all of which may be justified, or getting CT

Ranunculaceae of the Western Ukraine. І. Identification key

Directory of Open Access Journals (Sweden)

Andrew V. Novikoff

2013-04-01

Full Text Available In these paper the identification key for Ranunculaceae of Lviv, Transcarpathian (Zakarpattia, Rivne, Volhynia, Ivano-Frankivsk, Chernivtsi, Ternopil and Khmelnitsk regions (oblasts is introduced. The key includes 102 species. It is based on contemporary investigations on taxonomy of the family Ranunculaceae. The key is carried out up to the level of species but in some cases there are short remarks about subspecific structure of selected taxa. Also it is supported by short notes about distribution, ornamental usage and protection of represented species.

Single-molecule electronics: Cooling individual vibrational modes by the tunneling current.

Science.gov (United States)

Lykkebo, Jacob; Romano, Giuseppe; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

2016-03-21

Electronic devices composed of single molecules constitute the ultimate limit in the continued downscaling of electronic components. A key challenge for single-molecule electronics is to control the temperature of these junctions. Controlling heating and cooling effects in individual vibrational modes can, in principle, be utilized to increase stability of single-molecule junctions under bias, to pump energy into particular vibrational modes to perform current-induced reactions, or to increase the resolution in inelastic electron tunneling spectroscopy by controlling the life-times of phonons in a molecule by suppressing absorption and external dissipation processes. Under bias the current and the molecule exchange energy, which typically results in heating of the molecule. However, the opposite process is also possible, where energy is extracted from the molecule by the tunneling current. Designing a molecular "heat sink" where a particular vibrational mode funnels heat out of the molecule and into the leads would be very desirable. It is even possible to imagine how the vibrational energy of the other vibrational modes could be funneled into the "cooling mode," given the right molecular design. Previous efforts to understand heating and cooling mechanisms in single molecule junctions have primarily been concerned with small models, where it is unclear which molecular systems they correspond to. In this paper, our focus is on suppressing heating and obtaining current-induced cooling in certain vibrational modes. Strategies for cooling vibrational modes in single-molecule junctions are presented, together with atomistic calculations based on those strategies. Cooling and reduced heating are observed for two different cooling schemes in calculations of atomistic single-molecule junctions.

A novel role for small molecule glycomimetics in the protection against lipid-induced endothelial dysfunction: Involvement of Akt/eNOS and Nrf2/ARE signaling.

Science.gov (United States)

Mahmoud, Ayman M; Wilkinson, Fiona L; Jones, Alan M; Wilkinson, James A; Romero, Miguel; Duarte, Juan; Alexander, M Yvonne

2017-01-01

Glycomimetics are a diverse array of saccharide-inspired compounds, designed to mimic the bioactive functions of glycosaminoglycans. Therefore, glycomimetics represent a unique source of novel therapies to target aberrant signaling and protein interactions in a wide range of diseases. We investigated the protective effects of four newly synthesized small molecule glycomimetics against lipid-induced endothelial dysfunction, with an emphasis on nitric oxide (NO) and oxidative stress. Four aromatic sugar mimetics were synthesized by the stepwise transformation of 2,5-dihydroxybenzoic acid to derivatives (C1-C4) incorporating sulfate groups to mimic the structure of heparan sulfate. Glycomimetic-treated human umbilical vein endothelial cells (HUVECs) were exposed to palmitic acid to model lipid-induced oxidative stress. Palmitate-induced impairment of NO production was restored by the glycomimetics, through activation of Akt/eNOS signaling. Furthermore, C1-C4 significantly inhibited palmitate-induced reactive oxygen species (ROS) production, lipid peroxidation, and activity and expression of NADPH oxidase. These effects were attributed to activation of the Nrf2/ARE pathway and downstream activation of cellular antioxidant and cytoprotective proteins. In ex vivo vascular reactivity studies, the glycomimetics (C1-C4) also demonstrated a significant improvement in endothelium-dependent relaxation and decreased ROS production and NADPH oxidase activity in isolated mouse thoracic aortic rings exposed to palmitate. The small molecule glycomimetics, C1-C4, protect against lipid-induced endothelial dysfunction through up-regulation of Akt/eNOS and Nrf2/ARE signaling pathways. Thus, carbohydrate-derived therapeutics are a new class of glycomimetic drugs targeting endothelial dysfunction, regarded as the first line of defense against vascular complications in cardiovascular disease. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecule nanoweaver

Science.gov (United States)

Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

2009-03-10

A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

On ethical issues in radiation protection

International Nuclear Information System (INIS)

Persson, L.

1996-01-01

From an ethical viewpoint the author surveys existing international radiation protection recommendations and standards. After outlining previous work on the ethics of radiation protection, professional ethics, and the ethics of human radiation experiments, the author discusses ethical thinking on seven key issues related to radiation protection and ethics. (author)

The calculation of thermodynamic properties of molecules

DEFF Research Database (Denmark)

van Speybroeck, Veronique; Gani, Rafiqul; Meier, Robert Johan

2010-01-01

Thermodynamic data are key in the understanding and design of chemical processes. Next to the experimental evaluation of such data, computational methods are valuable and sometimes indispensable tools in obtaining heats of formation and Gibbs free energies. The major toolboxes to obtain such quan......Thermodynamic data are key in the understanding and design of chemical processes. Next to the experimental evaluation of such data, computational methods are valuable and sometimes indispensable tools in obtaining heats of formation and Gibbs free energies. The major toolboxes to obtain...... molecules the combination of group contribution methods with group additive values that are determined with the best available computational ab initio methods seems to be a viable alternative to obtain thermodynamic properties near chemical accuracy. New developments and full use of existing tools may lead...

Comparative Analysis of Immune Checkpoint Molecules and Their Potential Role in the Transmissible Tasmanian Devil Facial Tumor Disease

Directory of Open Access Journals (Sweden)

Andrew S. Flies

2017-05-01

Full Text Available Immune checkpoint molecules function as a system of checks and balances that enhance or inhibit immune responses to infectious agents, foreign tissues, and cancerous cells. Immunotherapies that target immune checkpoint molecules, particularly the inhibitory molecules programmed cell death 1 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4, have revolutionized human oncology in recent years, yet little is known about these key immune signaling molecules in species other than primates and rodents. The Tasmanian devil facial tumor disease is caused by transmissible cancers that have resulted in a massive decline in the wild Tasmanian devil population. We have recently demonstrated that the inhibitory checkpoint molecule PD-L1 is upregulated on Tasmanian devil (Sarcophilus harrisii facial tumor cells in response to the interferon-gamma cytokine. As this could play a role in immune evasion by tumor cells, we performed a thorough comparative analysis of checkpoint molecule protein sequences among Tasmanian devils and eight other species. We report that many of the key signaling motifs and ligand-binding sites in the checkpoint molecules are highly conserved across the estimated 162 million years of evolution since the last common ancestor of placental and non-placental mammals. Specifically, we discovered that the CTLA-4 (MYPPPY ligand-binding motif and the CTLA-4 (GVYVKM inhibitory domain are completely conserved across all nine species used in our comparative analysis, suggesting that the function of CTLA-4 is likely conserved in these species. We also found that cysteine residues for intra- and intermolecular disulfide bonds were also highly conserved. For instance, all 20 cysteine residues involved in disulfide bonds in the human 4-1BB molecule were also present in devil 4-1BB. Although many key sequences were conserved, we have also identified immunoreceptor tyrosine-based inhibitory motifs (ITIMs and immunoreceptor tyrosine-based switch

Silicon photon-counting avalanche diodes for single-molecule fluorescence spectroscopy

Science.gov (United States)

Michalet, Xavier; Ingargiola, Antonino; Colyer, Ryan A.; Scalia, Giuseppe; Weiss, Shimon; Maccagnani, Piera; Gulinatti, Angelo; Rech, Ivan; Ghioni, Massimo

2014-01-01

Solution-based single-molecule fluorescence spectroscopy is a powerful experimental tool with applications in cell biology, biochemistry and biophysics. The basic feature of this technique is to excite and collect light from a very small volume and work in a low concentration regime resulting in rare burst-like events corresponding to the transit of a single molecule. Detecting photon bursts is a challenging task: the small number of emitted photons in each burst calls for high detector sensitivity. Bursts are very brief, requiring detectors with fast response time and capable of sustaining high count rates. Finally, many bursts need to be accumulated to achieve proper statistical accuracy, resulting in long measurement time unless parallelization strategies are implemented to speed up data acquisition. In this paper we will show that silicon single-photon avalanche diodes (SPADs) best meet the needs of single-molecule detection. We will review the key SPAD parameters and highlight the issues to be addressed in their design, fabrication and operation. After surveying the state-of-the-art SPAD technologies, we will describe our recent progress towards increasing the throughput of single-molecule fluorescence spectroscopy in solution using parallel arrays of SPADs. The potential of this approach is illustrated with single-molecule Förster resonance energy transfer measurements. PMID:25309114

Flavonoids – Small Molecules, High Hopes

Directory of Open Access Journals (Sweden)

Sandu Mariana

2017-07-01

Full Text Available This brief review takes a look at flavonoids, a wide class of polyphenols, which are regarded as plant secondary metabolites. Their roles in plants are diverse and little understood. They can act as growth hormone modulators, phytoalexins, they offer UV protection, contribute to pollen viability and can function as signaling molecules in establishing symbiotic relationships. Flavonoids were also found to have a range of beneficial effects for the human body. Their anticancer, antioxidant, anti-inflammatory and cardioprotective activity, as well as their antibacterial, antiviral and antihelmintic properties make them promising candidates for the design of new drugs.

Diffie-Hellman Key Exchange through Steganographied Images

Directory of Open Access Journals (Sweden)

Amine Khaldi

2018-05-01

Full Text Available Purpose – In a private key system, the major problem is the exchange of the key between the two parties. Diffie and Hellman have set up a way to share the key. However, this technique is not protected against a man-in-the-middle attack as the settings are not authenticated. The Diffie-Hellman key exchange requires the use of digital signature or creating a secure channel for data exchanging to avoid the man-in-the-middle attack. Methodology/approach/design – We present a Diffie-Hellman key exchange implementation using steganographied images. Using steganography made invisible the data exchange to a potential attacker. So, we will not need a digital signature or creating a secure channel to do our key exchange since only the two concerned parts are aware of this exchange. Findings – We generate a symmetric 128-bit key between two users without use of digital signature or secure channel. However, it works only on bitmap images, heavy images and sensitive to compression.

Adsorption behavior of NH3 and NO2 molecules on stanene and stanane nanosheets - A density functional theory study

Science.gov (United States)

Nagarajan, V.; Chandiramouli, R.

2018-03-01

Using density functional theory method, we investigate the adsorption properties of NH3 and NO2 molecules on stanene and stanane nanosheets. The adsorption of molecules is explored based on the charge transfer, energetics, energy band gap and average energy gap variation. Moreover, the optimal adsorption sites of NH3 and NO2 molecules are identified on stanene and stanane nanosheets. Besides, the state-of-the-art provides the key features for the development of chemi-resistive nanosensor based on stanene and stanane nanosheets upon adsorption of NH3 and NO2 molecules. Furthermore, the study shows that adsorption of NO2 molecules is more prominent rather than NH3 molecules.

Antioxidant role of glutathione S-transferases: 4-Hydroxynonenal, a key molecule in stress-mediated signaling

International Nuclear Information System (INIS)

Singhal, Sharad S.; Singh, Sharda P.; Singhal, Preeti; Horne, David; Singhal, Jyotsana; Awasthi, Sanjay

2015-01-01

4-Hydroxy-2-trans-nonenal (4HNE), one of the major end products of lipid peroxidation (LPO), has been shown to induce apoptosis in a variety of cell lines. It appears to modulate signaling processes in more than one way because it has been suggested to have a role in signaling for differentiation and proliferation. It has been known that glutathione S-transferases (GSTs) can reduce lipid hydroperoxides through their Se-independent glutathione-peroxidase activity and that these enzymes can also detoxify LPO end-products such as 4HNE. Available evidence from earlier studies together with results of recent studies in our laboratories strongly suggests that LPO products, particularly hydroperoxides and 4HNE, are involved in the mechanisms of stress-mediated signaling and that it can be modulated by the alpha-class GSTs through the regulation of the intracellular concentrations of 4HNE. We demonstrate that 4HNE induced apoptosis in various cell lines is accompanied with c-Jun-N-terminal kinase (JNK) and caspase-3 activation. Cells exposed to mild, transient heat or oxidative stress acquire the capacity to exclude intracellular 4HNE at a faster rate by inducing GSTA4-4 which conjugates 4HNE to glutathione (GSH), and RLIP76 which mediates the ATP-dependent transport of the GSH-conjugate of 4HNE (GS-HNE). The balance between formation and exclusion promotes different cellular processes — higher concentrations of 4HNE promote apoptosis; whereas, lower concentrations promote proliferation. In this article, we provide a brief summary of the cellular effects of 4HNE, followed by a review of its GST-catalyzed detoxification, with an emphasis on the structural attributes that play an important role in the interactions with alpha-class GSTA4-4. Taken together, 4HNE is a key signaling molecule and that GSTs being determinants of its intracellular concentrations, can regulate stress-mediated signaling, are reviewed in this article. - Highlights: • GSTs are the major

Securing information using optically generated biometric keys

Science.gov (United States)

Verma, Gaurav; Sinha, Aloka

2016-11-01

In this paper, we present a new technique to obtain biometric keys by using the fingerprint of a person for an optical image encryption system. The key generation scheme uses the fingerprint biometric information in terms of the amplitude mask (AM) and the phase mask (PM) of the reconstructed fingerprint image that is implemented using the digital holographic technique. Statistical tests have been conducted to check the randomness of the fingerprint PM key that enables its usage as an image encryption key. To explore the utility of the generated biometric keys, an optical image encryption system has been further demonstrated based on the phase retrieval algorithm and the double random phase encoding scheme in which keys for the encryption are used as the AM and the PM key. The advantage associated with the proposed scheme is that the biometric keys’ retrieval requires the simultaneous presence of the fingerprint hologram and the correct knowledge of the reconstruction parameters at the decryption stage, which not only verifies the authenticity of the person but also protects the valuable fingerprint biometric features of the keys. Numerical results are carried out to prove the feasibility and the effectiveness of the proposed encryption system.

Small molecule antagonists of integrin receptors.

Science.gov (United States)

Perdih, A; Dolenc, M Sollner

2010-01-01

The complex and widespread family of integrin receptors is involved in numerous physiological processes, such as tissue remodeling, angiogenesis, development of the immune response and homeostasis. In addition, their key role has been elucidated in important pathological disorders such as cancer, cardiovascular diseases, osteoporosis, autoimmune and inflammatory diseases and in the pathogenesis of infectious diseases, making them highly important targets for modern drug design campaigns. In this review we seek to present a concise overview of the small molecule antagonists of this diverse and highly complex receptor family. Integrin antagonists are classified according to the targeted integrin receptor and are discussed in four sections. First we present the fibrinogen alpha(IIb)beta3 and the vitronectin alpha (V)beta(3) receptor antagonists. The remaining selective integrin antagonists are examined in the third section. The final section is dedicated to molecules with dual or multiple integrin activity. In addition, the use of antibodies and peptidomimetic approaches to modulate the integrin receptors are discussed, as well providing the reader with an overall appreciation of the field.

Leucine-rich repeat-containing synaptic adhesion molecules as organizers of synaptic specificity and diversity.

Science.gov (United States)

Schroeder, Anna; de Wit, Joris

2018-04-09

The brain harbors billions of neurons that form distinct neural circuits with exquisite specificity. Specific patterns of connectivity between distinct neuronal cell types permit the transfer and computation of information. The molecular correlates that give rise to synaptic specificity are incompletely understood. Recent studies indicate that cell-surface molecules are important determinants of cell type identity and suggest that these are essential players in the specification of synaptic connectivity. Leucine-rich repeat (LRR)-containing adhesion molecules in particular have emerged as key organizers of excitatory and inhibitory synapses. Here, we discuss emerging evidence that LRR proteins regulate the assembly of specific connectivity patterns across neural circuits, and contribute to the diverse structural and functional properties of synapses, two key features that are critical for the proper formation and function of neural circuits.

Protecting privacy in a clinical data warehouse.

Science.gov (United States)

Kong, Guilan; Xiao, Zhichun

2015-06-01

Peking University has several prestigious teaching hospitals in China. To make secondary use of massive medical data for research purposes, construction of a clinical data warehouse is imperative in Peking University. However, a big concern for clinical data warehouse construction is how to protect patient privacy. In this project, we propose to use a combination of symmetric block ciphers, asymmetric ciphers, and cryptographic hashing algorithms to protect patient privacy information. The novelty of our privacy protection approach lies in message-level data encryption, the key caching system, and the cryptographic key management system. The proposed privacy protection approach is scalable to clinical data warehouse construction with any size of medical data. With the composite privacy protection approach, the clinical data warehouse can be secure enough to keep the confidential data from leaking to the outside world. © The Author(s) 2014.

Control Strategy for Small Molecule Impurities in Antibody-Drug Conjugates.

Science.gov (United States)

Gong, Hai H; Ihle, Nathan; Jones, Michael T; Kelly, Kathleen; Kott, Laila; Raglione, Thomas; Whitlock, Scott; Zhang, Qunying; Zheng, Jie

2018-04-01

Antibody-drug conjugates (ADCs) are an emerging class of biopharmaceuticals. As such, there are no specific guidelines addressing impurity limits and qualification requirements. The current ICH guidelines on impurities, Q3A (Impurities in New Drug Substances), Q3B (Impurities in New Drug Products), and Q6B (Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products) do not adequately address how to assess small molecule impurities in ADCs. The International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) formed an impurities working group (IWG) to discuss this issue. This white paper presents a strategy for evaluating the impact of small molecule impurities in ADCs. This strategy suggests a science-based approach that can be applied to the design of control systems for ADC therapeutics. The key principles that form the basis for this strategy include the significant difference in molecular weights between small molecule impurities and the ADC, the conjugation potential of the small molecule impurities, and the typical dosing concentrations and dosing schedule. The result is that exposure to small impurities in ADCs is so low as to often pose little or no significant safety risk.

The study of excited oxygen molecule gas species production and quenching on thermal protection system materials

Science.gov (United States)

Nordine, Paul C.; Fujimoto, Gordon T.; Greene, Frank T.

1987-01-01

The detection of excited oxygen and ozone molecules formed by surface catalyzed oxygen atom recombination and reaction was investigated by laser induced fluorescence (LIF), molecular beam mass spectrometric (MBMS), and field ionization (FI) techniques. The experiment used partially dissociated oxygen flows from a microwave discharge at pressures in the range from 60 to 400 Pa or from an inductively coupled RF discharge at atmospheric pressure. The catalyst materials investigated were nickel and the reaction cured glass coating used for Space Shuttle reusable surface insulation tiles. Nonradiative loss processes for the laser excited states makes LIF detection of O2 difficult such that formation of excited oxygen molecules could not be detected in the flow from the microwave discharge or in the gaseous products of atom loss on nickel. MBMS experiments showed that ozone was a product of heterogeneous O atom loss on nickel and tile surfaces at low temperatures and that ozone is lost on these materials at elevated temperatures. FI was separately investigated as a method by which excited oxygen molecules may be conveniently detected. Partial O2 dissociation decreases the current produced by FI of the gas.

License protection with a tamper-resistant token

NARCIS (Netherlands)

Chong, C.N.; Ren, Bin; Doumen, J.M.; Etalle, Sandro; Hartel, Pieter H.; Corin, R.J.; Lim, Chae Hoon; Yung, Moti

Content protection mechanisms are intended to enforce the usage rights on the content. These usage rights are carried by a license. Sometimes, a license even carries the key that is used to unlock the protected content. Unfortunately, license protection is difficult, yet it is important for digital

Implementation of a Wireless Time Distribution Testbed Protected with Quantum Key Distribution

Energy Technology Data Exchange (ETDEWEB)

Bonior, Jason D [ORNL; Evans, Philip G [ORNL; Sheets, Gregory S [ORNL; Jones, John P [ORNL; Flynn, Toby H [ORNL; O' Neil, Lori Ross [Pacific Northwest National Laboratory (PNNL); Hutton, William [Pacific Northwest National Laboratory (PNNL); Pratt, Richard [Pacific Northwest National Laboratory (PNNL); Carroll, Thomas E. [Pacific Northwest National Laboratory (PNNL)

2017-01-01

Secure time transfer is critical for many timesensitive applications. the Global Positioning System (GPS) which is often used for this purpose has been shown to be susceptible to spoofing attacks. Quantum Key Distribution offers a way to securely generate encryption keys at two locations. Through careful use of this information it is possible to create a system that is more resistant to spoofing attacks. In this paper we describe our work to create a testbed which utilizes QKD and traditional RF links. This testbed will be used for the development of more secure and spoofing resistant time distribution protocols.

Bombardment of gas molecules on single graphene layer at high temperature

Energy Technology Data Exchange (ETDEWEB)

Murugesan, Ramki [School of Mechanical and Aerospace Engineering, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of); Park, Jae Hyun [Department of Aerospace and System Engineering and Research Center for Aircraft Parts Technology, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of); Ha, Dong Sung [Future Propulsion Center, Agency for Defense Development, Daejeon 305-600 (Korea, Republic of)

2014-12-09

Graphite is widely used as a material for rocket-nozzle inserts due to its excellent thermo-physical properties as well as low density. During the operation of rockets, the surface of the graphite nozzle is subjected to very high heat fluxes and the undesirable erosion of the surface occurs due to the bombardment of gas molecules with high kinetic energy, which causes a significant reduction of nozzle performance. However, the understanding and quantification of such bombardment is not satisfactory due to its complexity: The bond breaking-forming happens simultaneously for the carbon atoms of graphene, some gas molecules penetrate through the surface, some of them are reflected from the surface, etc. In the present study, we perform extensive molecular dynamics (MD) simulations to examine the bombardment phenomena in high temperature environment (several thousand Kelvin). Advanced from the previous studies that have focused on the bombardment by light molecules (e.g., H{sub 2}), we will concentrate on the impact by realistic molecules (e.g., CO{sub 2} and H{sub 2}O). LAMMPS is employed for the MD simulations with NVE ensemble and AIREBO potential for graphene. The molecular understanding of the interaction between graphene and highly energetic gas molecules will enable us to design an efficient thermo-mechanical protection system.

Structure and Structure-activity Relationship of Functional Organic Molecules

Institute of Scientific and Technical Information of China (English)

2011-01-01

@@ Research theme The group is made up of junior scientists from the State Key Laboratory of Elemento-organic Chemistry, Nankai University.The scientists focus their studis on the structure and structure-activity relationship of functional organic molecules not only because it has been the basis of their research, but also because the functional study of organic compounds is now a major scientific issue for organic chemists around the world.

Constitutive MHC class I molecules negatively regulate TLR-triggered inflammatory responses via the Fps-SHP-2 pathway.

Science.gov (United States)

Xu, Sheng; Liu, Xingguang; Bao, Yan; Zhu, Xuhui; Han, Chaofeng; Zhang, Peng; Zhang, Xuemin; Li, Weihua; Cao, Xuetao

2012-04-22

The molecular mechanisms that fine-tune Toll-like receptor (TLR)-triggered innate inflammatory responses remain to be fully elucidated. Major histocompatibility complex (MHC) molecules can mediate reverse signaling and have nonclassical functions. Here we found that constitutively expressed membrane MHC class I molecules attenuated TLR-triggered innate inflammatory responses via reverse signaling, which protected mice from sepsis. The intracellular domain of MHC class I molecules was phosphorylated by the kinase Src after TLR activation, then the tyrosine kinase Fps was recruited via its Src homology 2 domain to phosphorylated MHC class I molecules. This led to enhanced Fps activity and recruitment of the phosphatase SHP-2, which interfered with TLR signaling mediated by the signaling molecule TRAF6. Thus, constitutive MHC class I molecules engage in crosstalk with TLR signaling via the Fps-SHP-2 pathway and control TLR-triggered innate inflammatory responses.

Potential ecological impacts of an oil spill in the Florida Keys

International Nuclear Information System (INIS)

Moore, E.A.; Swain, H.M.

1991-01-01

The Florida Keys are a unique ecosystem of natural communities, natural resources, and high biodiversity. The strong emphasis placed on the protection of the environment is reflected in the wide variety of parks and protected areas. The possibility of a major oil spill from extensive tanker and freighter traffic in the Florida Straits is cause for concern since all of the natural communities and associated biota in the coastal and marine environments are vulnerable to oiling. This paper will review and synthesize available information and present new data concerning the potential ecological impacts of a major spill in the Florida Keys. The review will focus on: the distribution of natural communities; the presence of endangered species; the location of parks and protected areas; and the abundance of natural resources

Contribution of the protector adsorbed by the active site to the enzyme protection against γ-radiation

International Nuclear Information System (INIS)

Kravetskaya, T.P.; Krutyakov, V.M.; Sverdlov, A.G.

1976-01-01

It has been shown that 5-methoxytryptamine (mexamine) is a competitive inhibitor of trypsin. This prompted compairing the protection of the enzyme under varying conditions, that is: 90 per cent of the enzyme molecules are in a free state and 90 per cent of the enzyme molecules are bound with the protector molecules. A four-time increase in the protecting effect was observed with the protector bound to the active site of trypsin. A quantitative comparison of the trypsin protection by a tissue extract of a ''cellular'' concentration and by mexamine of a maximum ''organismal'' concentration has shown that radical scavenging is not a principal mechanism responsible for the protector effect in a cell even if the adsorption of the protector on the biopolymers is taken into account

77 FR 37060 - Critical Infrastructure and Key Resources (CIKR) Asset Protection Technical Assistance Program...

Science.gov (United States)

2012-06-20

.../IP/IICD, 245 Murray Lane SW., Mailstop 0602, Arlington, VA 20598-0602. Email requests should go to...), National Protection and Programs Directorate (NPPD), Office of Infrastructure Protection (IP... the following methods: Federal eRulemaking Portal: http://www.regulations.gov . Email: Include the...

Connections between molecular photoionization and electron-molecule scattering with emphasis on shape resonances

International Nuclear Information System (INIS)

Dehmer, J.L.; Dill, D.

1979-01-01

Most of our detailed information on the spectroscopy and dynamics of the electronic continuum of molecules is based on the complementary probes - photoionization and electron scattering. Though usually studied separately, it is most useful to appreciate the connections between these two processes since our understanding of one is often the key to interpreting or even generating new results in the other. We approach this subject in two steps. First, we very briefly outline the well-established connections, e.g., the Bethe-Born theory and comparisons of isoelectronic systems. Then we focus on a point of contact - the role of shape resonances in molecular photoionization and electron-molecule scattering - for which a substantial amount of new information has become available. Specific topics include mapping of resonances from the neutral (hν + molecule) to the negative ion (e + molecule) system, angular distributions, and interaction with vibration

Far-Infrared Spectroscopy of Weakly Bound Hydrated Cluster Molecules

DEFF Research Database (Denmark)

Andersen, Jonas

The thermodynamic properties of condensed phases, the functionality of many materials and the molecular organization in biological organisms are all governed by the classes of non-covalent interactions that occur already on the microscopic scale between pairs of molecules. A detailed investigation...... of the intermolecular interactions between prototypical molecular assemblies are valuable for accurate descriptions of larger supramolecular systems such as materials, gas hydrates and biological macromolecules. The aim of this PhD dissertation is to investigate intermolecular interactions fora series of medium...... vibrational bands of the cluster molecules in the challenging far-infrared and terahertz spectral regions.A key parameter in the validation of the performance of theoretical predictions for weak non-covalent intermolecular interactions is the dissociation energy D0 that depends heavily on the class of large...

BODIPY star-shaped molecules as solid state colour converters for visible light communications

Energy Technology Data Exchange (ETDEWEB)

Vithanage, D. A.; Manousiadis, P. P.; Sajjad, M. T.; Samuel, I. D. W., E-mail: idws@st-andrews.ac.uk, E-mail: gat@st-andrews.ac.uk; Turnbull, G. A., E-mail: idws@st-andrews.ac.uk, E-mail: gat@st-andrews.ac.uk [Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, St. Andrews KY16 9SS (United Kingdom); Rajbhandari, S. [School of Computing, Electronics and Mathematics, Coventry University, Coventry, West Midlands CV1 2JH (United Kingdom); Department of Engineering Science, University of Oxford, Oxford OX1 3PJ (United Kingdom); Chun, H.; Faulkner, G.; O' Brien, D. C. [Department of Engineering Science, University of Oxford, Oxford OX1 3PJ (United Kingdom); Orofino, C.; Cortizo-Lacalle, D.; Findlay, N. J.; Skabara, P. J. [WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL (United Kingdom); Kanibolotsky, A. L. [WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow G1 1XL (United Kingdom); Institute of Physical-Organic Chemistry and Coal Chemistry, 02160 Kyiv (Ukraine)

2016-07-04

In this paper, we study a family of solid-state, organic semiconductors for visible light communications. The star-shaped molecules have a boron-dipyrromethene (BODIPY) core with a range of side arm lengths which control the photophysical properties. The molecules emit red light with photoluminescence quantum yields ranging from 22% to 56%. Thin films of the most promising BODIPY molecules were used as a red colour converter for visible light communications. The film enabled colour conversion with a modulation bandwidth of 73 MHz, which is 16 times higher than that of a typical phosphor used in LED lighting systems. A data rate of 370 Mbit/s was demonstrated using On-Off keying modulation in a free space link with a distance of ∼15 cm.

Projections of change in key ecosystem indicators for planning and management of marine protected areas: An example study for European seas

Science.gov (United States)

Kay, Susan; Butenschön, Momme

2018-02-01

Marine Protected Areas (MPAs) are widely used as tools to maintain biodiversity, protect habitats and ensure that development is sustainable. If MPAs are to maintain their role into the future it is important for managers to understand how conditions at these sites may change as a result of climate change and other drivers, and this understanding needs to extend beyond temperature to a range of key ecosystem indicators. This case study demonstrates how spatially-aggregated model results for multiple variables can provide useful projections for MPA planners and managers. Conditions in European MPAs have been projected for the 2040s using unmitigated and globally managed scenarios of climate change and river management, and hence high and low emissions of greenhouse gases and riverborne nutrients. The results highlight the vulnerability of potential refuge sites in the north-west Mediterranean and the need for careful monitoring at MPAs to the north and west of the British Isles, which may be affected by changes in Atlantic circulation patterns. The projections also support the need for more MPAs in the eastern Mediterranean and Adriatic Sea, and can inform the selection of sites.

Production of carbon-14 and preparation of some key precursors for labeling organic molecules

International Nuclear Information System (INIS)

Moriya, T.; Motoishi, S.

1992-01-01

Production of carbon-14 on 50 GBq scale has been performed by neutron irradiation of aluminium nitride target in the JMTR. This nuclide is separated in carbon dioxide form by combustion of the irradiated target at 1100degC with oxygen. The [ 14 C] carbon dioxide liberated thus is trapped in caustic solution and finally recovered as [ 14 C] barium carbonate. Some precursors useful for incorporating carbon-14 into a given organic molecule have been prepared. Precursors such as [1- 14 C] sodium acetate, [ 14 C] methanol and [ 14 C] potassium cyanide are prepared by rather conventional methods involving carbonation of methyl magnesium iodine, reduction of carbon dioxide with lithium aluminium hydride and reduction of carbonate with metallic potassium in the presence of ammonium salt, respectively. A catalytic polymerization of acetylene is used to prepare benzene. (author)

In Situ Detection of Organic Molecules on the Martian Surface With the Mars Organic Molecule Analyzer (MOMA) on Exomars 2018

Science.gov (United States)

Li, Xiang; Brinckerhoff, William B.; Pinnick, Veronica T; van Amerom, Friso H. W.; Danell, Ryan M.; Arevalo, Ricardo D., Jr.; Getty, Stephanie; Mahaffy, Paul R.

2015-01-01

The Mars Organic Molecule Analyzer (MOMA) investigation on the 2018 ExoMars rover will examine the chemical composition of samples acquired from depths of up to two meters below the martian surface, where organics may be protected from radiative and oxidative degradation. The MOMA instrument is centered around a miniaturized linear ion trap (LIT) that facilitates two modes of operation: i) pyrolysisgas chromatography mass spectrometry (pyrGC-MS); and, ii) laser desorptionionization mass spectrometry (LDI-MS) at ambient Mars pressures. The LIT also enables the structural characterization of complex molecules via complementary analytical capabilities, such as multi-frequency waveforms (i.e., SWIFT) and tandem mass spectrometry (MSMS). When combined with the complement of instruments in the rovers Pasteur Payload, MOMA has the potential to reveal the presence of a wide range of organics preserved in a variety of mineralogical environments, and to begin to understand the structural character and potential origin of those compounds.

40 CFR 63.2831 - Where can I find definitions of key words used in this subpart?

Science.gov (United States)

2010-07-01

... words used in this subpart? 63.2831 Section 63.2831 Protection of Environment ENVIRONMENTAL PROTECTION... Vegetable Oil Production What This Subpart Covers § 63.2831 Where can I find definitions of key words used in this subpart? You can find definitions of key words used in this subpart in § 63.2872. ...

Small-molecule inhibitor leads of ribosome-inactivating proteins developed using the doorstop approach.

Directory of Open Access Journals (Sweden)

Yuan-Ping Pang

2011-03-01

Full Text Available Ribosome-inactivating proteins (RIPs are toxic because they bind to 28S rRNA and depurinate a specific adenine residue from the α-sarcin/ricin loop (SRL, thereby inhibiting protein synthesis. Shiga-like toxins (Stx1 and Stx2, produced by Escherichia coli, are RIPs that cause outbreaks of foodborne diseases with significant morbidity and mortality. Ricin, produced by the castor bean plant, is another RIP lethal to mammals. Currently, no US Food and Drug Administration-approved vaccines nor therapeutics exist to protect against ricin, Shiga-like toxins, or other RIPs. Development of effective small-molecule RIP inhibitors as therapeutics is challenging because strong electrostatic interactions at the RIP•SRL interface make drug-like molecules ineffective in competing with the rRNA for binding to RIPs. Herein, we report small molecules that show up to 20% cell protection against ricin or Stx2 at a drug concentration of 300 nM. These molecules were discovered using the doorstop approach, a new approach to protein•polynucleotide inhibitors that identifies small molecules as doorstops to prevent an active-site residue of an RIP (e.g., Tyr80 of ricin or Tyr77 of Stx2 from adopting an active conformation thereby blocking the function of the protein rather than contenders in the competition for binding to the RIP. This work offers promising leads for developing RIP therapeutics. The results suggest that the doorstop approach might also be applicable in the development of other protein•polynucleotide inhibitors as antiviral agents such as inhibitors of the Z-DNA binding proteins in poxviruses. This work also calls for careful chemical and biological characterization of drug leads obtained from chemical screens to avoid the identification of irrelevant chemical structures and to avoid the interference caused by direct interactions between the chemicals being screened and the luciferase reporter used in screening assays.

Protected areas for environmental sustainability in Nigeria ...

African Journals Online (AJOL)

Michael Horsfall

Key words: Protected Areas, Aesthetics, Cultural Heritage, Guidebook. ... International Union for the Conservation of Nature (IUCN). ... and tourism within the city of Evanston, U.S.A ... that were protected and designated as forest reserves.

Protect the Ones You Love: Burns Safety

Science.gov (United States)

... Submit Search The CDC Protect the Ones You Love: Child Injuries are Preventable Note: Javascript is disabled ... ways you can help protect the children you love from burns. Key Prevention Tips To prevent burns ...

Our Galactic Neighbor Hosts Complex Organic Molecules

Science.gov (United States)

Hensley, Kerry

2018-03-01

For the first time, data from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the presence of methyl formate and dimethyl ether in a star-forming region outside our galaxy. This discovery has important implications for the formation and survival of complex organic compounds importantfor the formation of life in low-metallicity galaxies bothyoung and old.No Simple Picture of Complex Molecule FormationALMA, pictured here with the Magellanic Clouds above, has observed organic molecules in our Milky Way Galaxy and beyond. [ESO/C. Malin]Complex organic molecules (those with at least six atoms, one or more of which must be carbon) are the precursors to the building blocks of life. Knowing how and where complex organic molecules can form is a key part of understanding how life came to be on Earth and how it might arise elsewhere in the universe. From exoplanet atmospheres to interstellar space, complex organic molecules are ubiquitous in the Milky Way.In our galaxy, complex organic molecules are often found in the intense environments of hot cores clumps of dense molecular gas surrounding the sites of star formation. However, its not yet fully understood how the complex organic molecules found in hot cores come to be. One possibility is that the compounds condense onto cold dust grains long before the young stars begin heating their natal shrouds. Alternatively, they might assemble themselves from the hot, dense gas surrounding the blazing protostars.Composite infrared and optical image of the N 113 star-forming region in the LMC. The ALMA coverage is indicated by the gray line. Click to enlarge. [Sewio et al. 2018]Detecting Complexity, a Galaxy AwayUsing ALMA, a team of researchers led by Marta Sewio (NASA Goddard Space Flight Center) recently detected two complex organic molecules methyl formate and dimethyl ether for the first time in our neighboring galaxy, the Large Magellanic Cloud (LMC). Previous searches for organic molecules in the LMC detected

Atkins' molecules

CERN Document Server

Atkins, Peters

2003-01-01

Originally published in 2003, this is the second edition of a title that was called 'the most beautiful chemistry book ever written'. In it, we see the molecules responsible for the experiences of our everyday life - including fabrics, drugs, plastics, explosives, detergents, fragrances, tastes, and sex. With engaging prose Peter Atkins gives a non-technical account of an incredible range of aspects of the world around us, showing unexpected connections, and giving an insight into how this amazing world can be understood in terms of the atoms and molecules from which it is built. The second edition includes dozens of extra molecules, graphical presentation, and an even more accessible and enthralling account of the molecules themselves.

STICKING OF MOLECULES ON NONPOROUS AMORPHOUS WATER ICE

Energy Technology Data Exchange (ETDEWEB)

He, Jiao; Vidali, Gianfranco [Physics Department, Syracuse University, Syracuse, NY 13244 (United States); Acharyya, Kinsuk, E-mail: gvidali@syr.edu [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States)

2016-05-20

Accurate modeling of physical and chemical processes in the interstellar medium (ISM) requires detailed knowledge of how atoms and molecules adsorb on dust grains. However, the sticking coefficient, a number between 0 and 1 that measures the first step in the interaction of a particle with a surface, is usually assumed in simulations of ISM environments to be either 0.5 or 1. Here we report on the determination of the sticking coefficient of H{sub 2}, D{sub 2}, N{sub 2}, O{sub 2}, CO, CH{sub 4}, and CO{sub 2} on nonporous amorphous solid water. The sticking coefficient was measured over a wide range of surface temperatures using a highly collimated molecular beam. We showed that the standard way of measuring the sticking coefficient—the King–Wells method—leads to the underestimation of trapping events in which there is incomplete energy accommodation of the molecule on the surface. Surface scattering experiments with the use of a pulsed molecular beam are used instead to measure the sticking coefficient. Based on the values of the measured sticking coefficient, we suggest a useful general formula of the sticking coefficient as a function of grain temperature and molecule-surface binding energy. We use this formula in a simulation of ISM gas–grain chemistry to find the effect of sticking on the abundance of key molecules both on grains and in the gas phase.

Setting objectives for managing Key deer

Science.gov (United States)

Diefenbach, Duane R.; Wagner, Tyler; Stauffer, Glenn E.

2014-01-01

The U.S. Fish and Wildlife Service (FWS) is responsible for the protection and management of Key deer (Odocoileus virginianus clavium) because the species is listed as Endangered under the Endangered Species Act (ESA). The purpose of the ESA is to protect and recover imperiled species and the ecosystems upon which they depend. There are a host of actions that could possibly be undertaken to recover the Key deer population, but without a clearly defined problem and stated objectives it can be difficult to compare and evaluate alternative actions. In addition, management goals and the acceptability of alternative management actions are inherently linked to stakeholders, who should be engaged throughout the process of developing a decision framework. The purpose of this project was to engage a representative group of stakeholders to develop a problem statement that captured the management problem the FWS must address with Key deer and identify objectives that, if met, would help solve the problem. In addition, the objectives were organized in a hierarchical manner (i.e., an objectives network) to show how they are linked, and measurable attributes were identified for each objective. We organized a group of people who represented stakeholders interested in and potentially affected by the management of Key deer. These stakeholders included individuals who represented local, state, and federal governments, non-governmental organizations, the general public, and local businesses. This stakeholder group met five full days over the course of an eight-week period to identify objectives that would address the following problem:“As recovery and removal from the Endangered Species list is the purpose of the Endangered Species Act, the U.S. Fish and Wildlife Service needs a management approach that will ensure a sustainable, viable, and healthy Key deer population. Urbanization has affected the behavior and population dynamics of the Key deer and the amount and characteristics

Thermal ion-molecule reactions in oxygen-containing molecules

International Nuclear Information System (INIS)

Kumakura, Minoru

1981-02-01

The energetics of ions and the thermal ion-molecule reactions in oxygen-containing molecules have been studied with a modified time-of-flight mass spectrometer. It was found that the translational energy of ion can be easily obtained from analysis of the decay curve using the time-of-flight mass spectrometer. The condensation-elimination reactions proceeded via cross- and homo-elimination mechanism in which the nature of intermediate-complex could be correlated with the nature of reactant ion. It was elucidated that behavior of poly-atomic oxygen-containing ions on the condensation-elimination reactions is considerably influenced by their oxonium ion structures having functional groups. In addition, the rate constants of the condensation-elimination reactions have affected with the energy state of reactant ion and the dipole moment and/or the polarizability of neutral molecule. It was clarified that the rate constants of the ion-molecule clustering reactions in poly-atomic oxygen-containing molecules such as cyclic ether of six member rings are very large and the cluster ions are stable owing to the large number of vibrational degree of freedom in the cluster ions. (author)

Cold Rydberg molecules

Science.gov (United States)

Raithel, Georg; Zhao, Jianming

2017-04-01

Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. These include research on novel types of Rydberg molecules. Three types of molecules will be reviewed. Long-range, homonuclear Rydberg molecules, first predicted in [1] and observed in [2], are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium [3]). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules [3]. A classification into Hund's cases [3, 4, 5] will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction term of neutral Rydberg-Rydberg molecules is between two dipoles, while for ionic Rydberg molecules it is between a dipole and a monopole. NSF (PHY-1506093), NNSF of China (61475123).

Carbon Monoxide: An Essential Signalling Molecule

Science.gov (United States)

Mann, Brian E.

Carbon monoxide (CO), like nitric oxide (NO), is an essential signalling molecule in humans. It is active in the cardiovascular system as a vasodilator. In addition, CO possesses anti-inflammatory, anti-apoptotic and anti-proliferative properties and protects tissues from hypoxia and reperfusion injury. Some of its applications in animal models include suppression of organ graft rejection and safeguarding the heart during reperfusion after cardiopulmonary bypass surgery. CO also suppresses arteriosclerotic lesions following angioplasty, reverses established pulmonary hypertension and mitigates the development of post-operative ileus in the murine small intestine and the development of cerebral malaria in mice as well as graft-induced intimal hyperplasia in pigs. There have been several clinical trials using air-CO mixtures for the treatment of lung-, heart-, kidney- and abdominal-related diseases. This review examines the research involving the development of classes of compounds (with particular emphasis on metal carbonyls) that release CO, which could be used in clinically relevant conditions. The review is drawn not only from published papers in the chemical literature but also from the extensive biological literature and patents on CO-releasing molecules (CO-RMs).

Electron-excited molecule interactions

International Nuclear Information System (INIS)

Christophorou, L.G.; Tennessee Univ., Knoxville, TN

1991-01-01

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

40 CFR 63.1176 - Where can I find definitions of key words used in this subpart?

Science.gov (United States)

2010-07-01

... words used in this subpart? 63.1176 Section 63.1176 Protection of Environment ENVIRONMENTAL PROTECTION... Production § 63.1176 Where can I find definitions of key words used in this subpart? The definitions of key words used in this subpart are in the Clean Air Act (Act), in § 63.2 of the general provisions in...

Calculations of the Auger deexcitation rate of the dtμ within the muonic quasi-molecule, [(dtμ)dee

International Nuclear Information System (INIS)

Armour, E.A.G.; Lewis, D.M.; Hara, S.

1993-01-01

A key process in muon catalysed fusion is the deexcitation of the dtμ within the resonant muonic quasi-molecule [(dtμ)dee], by emission of an Auger electron. The dtμ in the quasi-molecule is initially in a weakly bound excited state with J = 1 and v = 1. In this paper, calculations taking full account of the molecular nature of the quasi-molecule are carried out of the rate of the dominant deexcitation to the state with J = 0 and v = 1. (orig.)

Concurrently Deniable Group Key Agreement and Its Application to Privacy-Preserving VANETs

Directory of Open Access Journals (Sweden)

Shengke Zeng

2018-01-01

Full Text Available VANETs need secure communication. Authentication in VANETs resists the attack on the receipt of false information. Authenticated group key agreement (GKA is used to establish a confidential and authenticated communication channel for the multiple vehicles. However, authentication incurs privacy leakage, that is, by using digital signature. Therefore, the deniability is deserved for GKA (which is termed as DGKA due to the privacy protection. In the DGKA protocol, each participant interacts with intended partners to establish a common group session key. After this agreement session, each participant can not only be regarded as the intended sender but also deny that it has ever participated in this session. Therefore, under this established key, vehicles send confidential messages with authentication property and the deniability protects the vehicles privacy. We present a novel transformation from an unauthenticated group key agreement to a deniable (authenticated group key agreement without increasing communication round. Our full deniability is achieved even in the concurrent setting which suits the Internet environment. In addition, we design an authenticated and privacy-preserving communication protocol for VANETs by using the proposed deniable group key agreement.

Single-molecule fluorescence microscopy review: shedding new light on old problems.

Science.gov (United States)

Shashkova, Sviatlana; Leake, Mark C

2017-08-31

Fluorescence microscopy is an invaluable tool in the biosciences, a genuine workhorse technique offering exceptional contrast in conjunction with high specificity of labelling with relatively minimal perturbation to biological samples compared with many competing biophysical techniques. Improvements in detector and dye technologies coupled to advances in image analysis methods have fuelled recent development towards single-molecule fluorescence microscopy, which can utilize light microscopy tools to enable the faithful detection and analysis of single fluorescent molecules used as reporter tags in biological samples. For example, the discovery of GFP, initiating the so-called 'green revolution', has pushed experimental tools in the biosciences to a completely new level of functional imaging of living samples, culminating in single fluorescent protein molecule detection. Today, fluorescence microscopy is an indispensable tool in single-molecule investigations, providing a high signal-to-noise ratio for visualization while still retaining the key features in the physiological context of native biological systems. In this review, we discuss some of the recent discoveries in the life sciences which have been enabled using single-molecule fluorescence microscopy, paying particular attention to the so-called 'super-resolution' fluorescence microscopy techniques in live cells, which are at the cutting-edge of these methods. In particular, how these tools can reveal new insights into long-standing puzzles in biology: old problems, which have been impossible to tackle using other more traditional tools until the emergence of new single-molecule fluorescence microscopy techniques. © 2017 The Author(s).

[Legal development of consumer protection from the Federal Office of Consumer Protection and Food Safety standpoint].

Science.gov (United States)

Püster, M

2010-06-01

Ten years after publication of the White Paper on Food Safety, health consumer protection has made significant progress and, today, is a key field in politics at both the European and German levels. In addition to the protection of health and security of consumers, consumer information has become a core element of consumer protection for the Federal Office of Consumer Protection and Food Safety (Bundesamt für Verbraucherschutz and Lebensmittelsicherheit, BVL). State authorities are provided with new means of communication and interaction with consumers.

A new class of pluripotent stem cell cytotoxic small molecules.

Directory of Open Access Journals (Sweden)

Mark Richards

Full Text Available A major concern in Pluripotent Stem Cell (PSC-derived cell replacement therapy is the risk of teratoma formation from contaminating undifferentiated cells. Removal of undifferentiated cells from differentiated cultures is an essential step before PSC-based cell therapies can be safely deployed in a clinical setting. We report a group of novel small molecules that are cytotoxic to PSCs. Our data indicates that these molecules are specific and potent in their activity allowing rapid eradication of undifferentiated cells. Experiments utilizing mixed PSC and primary human neuronal and cardiomyocyte cultures demonstrate that up to a 6-fold enrichment for specialized cells can be obtained without adversely affecting cell viability and function. Several structural variants were synthesized to identify key functional groups and to improve specificity and efficacy. Comparative microarray analysis and ensuing RNA knockdown studies revealed involvement of the PERK/ATF4/DDIT3 ER stress pathway. Surprisingly, cell death following ER stress induction was associated with a concomitant decrease in endogenous ROS levels in PSCs. Undifferentiated cells treated with these molecules preceding transplantation fail to form teratomas in SCID mice. Furthermore, these molecules remain non-toxic and non-teratogenic to zebrafish embryos suggesting that they may be safely used in vivo.

limits of copyright protection in contemporary nigeria

African Journals Online (AJOL)

Mofasony

2009-10-05

Oct 5, 2009 ... modes of protection of intellectual property, and has left the law completely in a .... “Nigerian Computer Software Protection in Nigeria" [www ...... H. Ryder & Smith, “Public key Encryptocraph Standards: R.S.A. Data Security”,.

Children in Africa: Key Statistics on Child Survival, Protection and Development

Science.gov (United States)

UNICEF, 2014

2014-01-01

This report presents key statistics relating to: (1) child malnutrition in Africa; (2) HIV/AIDS and Malaria in Africa; (3) child marriage, birth registration and Female Genital Mutilation/Cutting (FGM/C); (4) education in Africa; (5) child mortality in Africa; (6) Drinking water and sanitation in Africa; and (7) maternal health in Africa.…

Conjugated Molecules for the Smart Filtering of Intense Radiations

Directory of Open Access Journals (Sweden)

Danilo Dini

2003-04-01

Full Text Available Abstract: The practical realization of smart optical filters, i.e. devices which change their optical transmission in a suitable way to keep a working state for a general light sensitive element , can involve the use of conjugated molecules whose light absorption properties are light- intensity dependent (nonlinear optical effect. The verification of optical limiting displayed by some particular conjugated molecules, e.g. phthalocyanines, is quite noteworthy and can be successfully exploited for the realization of such smart optical devices. In the present contribution the analysis of the relevant molecular feature of a phthalocyanine are analyzed with the aim of determining useful correlations between optical limiting performance and phthalocyanine chemical structure. In particular , the electronic nature of the substituent is considered as a key factor for the explanation of some observed optical limiting trends.

Improved Mask Protected DES using RSA Algorithm

Directory of Open Access Journals (Sweden)

Asha Latha S.

2016-01-01

Full Text Available The data encryption standard is a pioneering and farsighted standard which helped to set a new paradigm for encryption standards. But now DES is considered to be insecure for some application. Asymmetric mask protected DES is an advanced encryption method for effectively protecting the advanced DES. There are still probabilities to improve its security. This paper propose a method, which introduce a RSA key generation scheme in mask protected DES instead of plain key, which result in enhancement in the security of present asymmetric mask protected DES. We further propose a Vedic mathematical method of RSA implementation which reduce the complexity of computation in RSA block thereby resulting in reduced delay (four timesthat improves the performance of overall system. The software implementation was performed using Xilinx 13.2 and Model-Sim was used for the simulation environment.

Rydberg Molecules for Ion-Atom Scattering in the Ultracold Regime.

Science.gov (United States)

Schmid, T; Veit, C; Zuber, N; Löw, R; Pfau, T; Tarana, M; Tomza, M

2018-04-13

We propose a novel experimental method to extend the investigation of ion-atom collisions from the so far studied cold, essentially classical regime to the ultracold, quantum regime. The key aspect of this method is the use of Rydberg molecules to initialize the ultracold ion-atom scattering event. We exemplify the proposed method with the lithium ion-atom system, for which we present simulations of how the initial Rydberg molecule wave function, freed by photoionization, evolves in the presence of the ion-atom scattering potential. We predict bounds for the ion-atom scattering length from ab initio calculations of the interaction potential. We demonstrate that, in the predicted bounds, the scattering length can be experimentally determined from the velocity of the scattered wave packet in the case of ^{6}Li^{+}-^{6}Li and from the molecular ion fraction in the case of ^{7}Li^{+}-^{7}Li. The proposed method to utilize Rydberg molecules for ultracold ion-atom scattering, here particularized for the lithium ion-atom system, is readily applicable to other ion-atom systems as well.

INFLUENCE OF SOLUBLE PLACENTAL TISSUE-DERIVED MOLECULES UPON EXPRESSION OF ADHESION MOLECULES BY EA.HY926 ENDOTHELIAL CELLS

Directory of Open Access Journals (Sweden)

O. I. Stepanova

2011-01-01

Full Text Available Abstract.  Leukocyte  recruitment  to  placental  tissue  is  an  important  factor  of  its  development.  In  this respect, adhesion molecules at the endothelial cell surface represent a key determining factor of leukocyte adhesion and their trans-endothelial migration. The goal of investigation was to evaluate changed expression of adhesion molecules on the endothelial cells induced by supernates of placental tissue cultures. Placental tissue supernatants produced by the first- and third-trimester placental tissue from normal pregnancy, as well as from women with gestosis, induced higher expression of CD31, CD9, CD62E, CD62P, CD34, CD54, CD51/61, CD49d  and  integrin  β7  expression  by  endothelial  cells,  as  compared  with  their  baseline  levels.  However, the  supernates  from  pre-eclamptic  placental  tissue (3rd  trimester  caused  an  increased  CD9  expression by  endothelial  cells,  as  compared  with  effects  of placental  supernates  from  eclampsia-free  cases.  Our data  contribute  to  understanding  a  possible  role  of endothelial cell adhesion molecules in recruitment of leukocytes to placental tissue and possible participation of adhesion molecules in pathogenesis of pre-eclampsia. The work was supported by a grant from Russian Ministry of Education and Science ГК №02.740.11.0711 and Presidential grant № НШ-3594.2010.7 and МД-150.2011.7. (Med. Immunol., 2011, vol. 13, N 6, pp 589-596

Optimisation of radiation protection

International Nuclear Information System (INIS)

1988-01-01

Optimisation of radiation protection is one of the key elements in the current radiation protection philosophy. The present system of dose limitation was issued in 1977 by the International Commission on Radiological Protection (ICRP) and includes, in addition to the requirements of justification of practices and limitation of individual doses, the requirement that all exposures be kept as low as is reasonably achievable, taking social and economic factors into account. This last principle is usually referred to as optimisation of radiation protection, or the ALARA principle. The NEA Committee on Radiation Protection and Public Health (CRPPH) organised an ad hoc meeting, in liaison with the NEA committees on the safety of nuclear installations and radioactive waste management. Separate abstracts were prepared for individual papers presented at the meeting

Strengthening the radiation protection culture: a priority of EDF radiation protection policy

International Nuclear Information System (INIS)

Garcier, Y.

2006-01-01

Full text of publication follows: In order to improve the management of radiation protection at EDF nuclear power plants, the Human Factors Group of the Research and Development Division of EDF has performed some studies on the appropriation process of the radiation protection requirements. These studies have notably shown that an efficient application of the radiation protection requirements lies on a comprehension by all workers of the meaning of these requirements. Furthermore, they should not be applied under the constraint or because of the fear of a sanction, but the workers need to perceive and understand the benefits in terms of protection associated with the radiation protection requirements. The strengthening of the radiation protection culture is therefore a key element of the radiation protection policy developed by EDF. This culture lies on an awareness of the health risks potentially associated with low levels of ionising radiations, as well as on the knowledge of tools, techniques and good practices developed to control the level of exposures and improve the radiation protection. Various type of actions have been undertaken to reinforce among the relevant players (exposed and non-exposed workers, contractors, all levels of management,... ) an awareness of radiation protection in order to integrate it in their day to day work: elaboration of a 'radiation protection system of reference' explaining how the radiation protection regulatory requirements are applied at EDF, publication of a 'radiation protection handbook' available for all workers (including contractors), training sessions, creation of networks of specialists from the various nuclear power plants on specific radiation protection issues, organisation of feed-back experience forum, etc. Beyond these specific actions, i t is also important to ensure a support and an assistance on the field by dedicated specialists. In this perspective, the health physicists have to play a key role in order to

Key residues of a major cytochrome P4502D6 epitope are located on the surface of the molecule.

Science.gov (United States)

Ma, Yun; Thomas, Mark G; Okamoto, Manabu; Bogdanos, Dimitrios P; Nagl, Sylvia; Kerkar, Nanda; Lopes, Agnel R; Muratori, Luigi; Lenzi, Marco; Bianchi, Francesco B; Mieli-Vergani, Giorgina; Vergani, Diego

2002-07-01

Eukaryotically expressed CYP2D6 is the universal target of liver kidney microsomal Ab type 1 (LKM1) in both type 2 autoimmune hepatitis (AIH) and chronic hepatitis C virus (HCV) infection. In contrast, reactivity to prokaryotically expressed CYP2D6 protein and synthetic peptides is significantly lower in HCV infection than in AIH. The aim of the present study was to characterize LKM1 reactivity against a panel of eukaryotically expressed CYP2D6 constructs in the two conditions. LKM1-positive sera obtained from 16 patients with AIH and 16 with HCV infection were used as probes to perform a complete epitope mapping of CYP2D6. Reactivity to the full-length protein and 16 constructs thereof was determined by radioligand assay. We found that antigenicity is confined to the portion of the molecule C-terminal of aa 193, no reactivity being detectable against the aa sequence 1-193. Reactivity increases stepwise toward the C-terminal in both AIH and HCV, but the frequency of reactivity in the two conditions differs significantly between aa 267-337. To further characterize this region, we introduced a five and a three amino acid swap mutation selected from the homologous regions of CYP2C9 and HCV. This maneuver resulted in a substantial loss of LKM1 binding in both conditions, suggesting that this region contains a major epitope. Molecular modeling revealed that CYP2D6(316-327) is exposed on the surface of the protein, and may represent a key target for the autoantibody. These findings provide an initial characterization of the antigenic constitution of the target of LKM1 in AIH and HCV infection.

Enrichment of antioxidants from soy sauce using macroporous resin and identification of 4-ethylguaiacol, catechol, daidzein, and 4-ethylphenol as key small molecule antioxidants in soy sauce.

Science.gov (United States)

Li, Huipin; Lin, Lianzhu; Feng, Yunzi; Zhao, Mouming; Li, Xiuting; Zhu, Qiyuan; Xiao, Zuobing

2018-02-01

The adsorption and desorption characteristics of seven macroporous resins on the antioxidants in soy sauce were investigated. SP-207 and SP-825 resins possessing good adsorption and desorption capacities were studied further. The pseudo-second-order kinetics and Langmuir isotherm models were demonstrated to be appropriate to describe the whole exothermic and physical adsorption processes of antioxidants onto resins. The 60% ethanol eluted fraction from soy sauce purified by SP-825 resin column possessed the strongest antioxidant activity. The antioxidant activities and contents of typical soy isoflavones, furanones, pyranones, and phenolic acids in soy sauce were determined. These compounds contributed to 50.02% of the total antioxidant activity of the SP-60% fraction. The key small molecule antioxidant compounds in soy sauce were identified as 4-ethylguaiacol, catechol, daidzein, and 4-ethylphenol by the antioxidants omission experiments. Additionally, the purified active fraction with high contents of antioxidants from soy sauce could be applied as bioactive ingredient in food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultra-cold molecule production

International Nuclear Information System (INIS)

Ramirez-Serrano, Jamie; Chandler, David W.; Strecker, Kevin; Rahn, Larry A.

2005-01-01

The production of Ultra-cold molecules is a goal of many laboratories through out the world. Here we are pursuing a unique technique that utilizes the kinematics of atomic and molecular collisions to achieve the goal of producing substantial numbers of sub Kelvin molecules confined in a trap. Here a trap is defined as an apparatus that spatially localizes, in a known location in the laboratory, a sample of molecules whose temperature is below one degree absolute Kelvin. Further, the storage time for the molecules must be sufficient to measure and possibly further cool the molecules. We utilize a technique unique to Sandia to form cold molecules from near mass degenerate collisions between atoms and molecules. This report describes the progress we have made using this novel technique and the further progress towards trapping molecules we have cooled

Public/private key certification authority and key distribution. Draft

Energy Technology Data Exchange (ETDEWEB)

Long, J.P.; Christensen, M.J.; Sturtevant, A.P.; Johnston, W.E.

1995-09-25

Traditional encryption, which protects messages from prying eyes, has been used for many decades. The present concepts of encryption are built from that heritage. Utilization of modern software-based encryption techniques implies much more than simply converting files to an unreadable form. Ubiquitous use of computers and advances in encryption technology coupled with the use of wide-area networking completely changed the reasons for utilizing encryption technology. The technology demands a new and extensive infrastructure to support these functions. Full understanding of these functions, their utility and value, and the need for an infrastructure, takes extensive exposure to the new paradigm. This paper addresses issues surrounding the establishment and operation of a key management system (i.e., certification authority) that is essential to the successful implementation and wide-spread use of encryption.

Molecules in stars

International Nuclear Information System (INIS)

Tsuji, T.

1986-01-01

Recently, research related to molecules in stars has rapidly expanded because of progress in related fields. For this reason, it is almost impossible to cover all the topics related to molecules in stars. Thus, here the authors focus their attention on molecules in the atmospheres of cool stars and do not cover in any detail topics related to circumstellar molecules originating from expanding envelopes located far from the stellar surface. However, the authors do discuss molecules in quasi-static circumstellar envelopes (a recently discovered new component of circumstellar envelopes) located near the stellar surface, since molecular lines originating from such envelopes show little velocity shift relative to photospheric lines, and hence they directly affect the interpretation and analysis of stellar spectra

Molecule Matters

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces. E Arunan. Feature Article Volume 14 Issue 4 April 2009 pp 346-356 ...

On the role of hydrogel structure and degradation in controlling the transport of cell-secreted matrix molecules for engineered cartilage.

Science.gov (United States)

Dhote, Valentin; Skaalure, Stacey; Akalp, Umut; Roberts, Justine; Bryant, Stephanie J; Vernerey, Franck J

2013-03-01

Damage to cartilage caused by injury or disease can lead to pain and loss of mobility, diminishing one's quality of life. Because cartilage has a limited capacity for self-repair, tissue engineering strategies, such as cells encapsulated in synthetic hydrogels, are being investigated as a means to restore the damaged cartilage. However, strategies to date are suboptimal in part because designing degradable hydrogels is complicated by structural and temporal complexities of the gel and evolving tissue along multiple length scales. To address this problem, this study proposes a multi-scale mechanical model using a triphasic formulation (solid, fluid, unbound matrix molecules) based on a single chondrocyte releasing extracellular matrix molecules within a degrading hydrogel. This model describes the key players (cells, proteoglycans, collagen) of the biological system within the hydrogel encompassing different length scales. Two mechanisms are included: temporal changes of bulk properties due to hydrogel degradation, and matrix transport. Numerical results demonstrate that the temporal change of bulk properties is a decisive factor in the diffusion of unbound matrix molecules through the hydrogel. Transport of matrix molecules in the hydrogel contributes both to the development of the pericellular matrix and the extracellular matrix and is dependent on the relative size of matrix molecules and the hydrogel mesh. The numerical results also demonstrate that osmotic pressure, which leads to changes in mesh size, is a key parameter for achieving a larger diffusivity for matrix molecules in the hydrogel. The numerical model is confirmed with experimental results of matrix synthesis by chondrocytes in biodegradable poly(ethylene glycol)-based hydrogels. This model may ultimately be used to predict key hydrogel design parameters towards achieving optimal cartilage growth. Copyright © 2012 Elsevier Ltd. All rights reserved.

Software piracy: Physical and legal protection methods

Energy Technology Data Exchange (ETDEWEB)

Orlandi, E

1991-02-01

Advantages and disadvantages, in terms of reliability and cost, are assessed for different physical and legal methods of protection of computer software, e.g., encryption and key management. The paper notes, however, that no protection system is 100% safe; the best approach is to implement a sufficient amount of protection such as to make piracy uneconomical relative to the risks involved.

Structural Analysis of ‘key’ Interactions in Functional RNA Molecules

KAUST Repository

Chawla, Mohit

2018-04-01

The main objective of the thesis is to carry out structural bioinformatics study along with usage of advanced quantum chemical methods to look at the structural stability and energetics of RNA building blocks. The main focus of the work described here lies on understanding the reasons behind the intrinsic stability of key interactions in nucleic acids. Crystal structures of RNA molecules exhibit fascinating variety of non-covalent interactions, which play an important role in maintaining the three dimensional structures. An accurate atomic level description of these interactions in the structural building blocks of RNA is a key to understand the structure-function relationship in these molecules. An effort has been made to link the conclusions drawn from quantum chemical computations on RNA base pairs in wide biochemical context of their occurrence in RNA structures. The initial attention was on the impact of natural and non-natural modifications of the nucleic acid bases on the structure and stability of base pairs that they are involved in. In the remaining sections we cover other molecular interactions shaping nucleic acids, as the interaction between ribose and the bases, and the fluoride sensing riboswitch system in order to investigate structure and dynamics of nucleic acids at the atomic level and to gain insight into the physical chemistry behind.

Structural Analysis of ‘key’ Interactions in Functional RNA Molecules

KAUST Repository

Chawla, Mohit

2018-01-01

The main objective of the thesis is to carry out structural bioinformatics study along with usage of advanced quantum chemical methods to look at the structural stability and energetics of RNA building blocks. The main focus of the work described here lies on understanding the reasons behind the intrinsic stability of key interactions in nucleic acids. Crystal structures of RNA molecules exhibit fascinating variety of non-covalent interactions, which play an important role in maintaining the three dimensional structures. An accurate atomic level description of these interactions in the structural building blocks of RNA is a key to understand the structure-function relationship in these molecules. An effort has been made to link the conclusions drawn from quantum chemical computations on RNA base pairs in wide biochemical context of their occurrence in RNA structures. The initial attention was on the impact of natural and non-natural modifications of the nucleic acid bases on the structure and stability of base pairs that they are involved in. In the remaining sections we cover other molecular interactions shaping nucleic acids, as the interaction between ribose and the bases, and the fluoride sensing riboswitch system in order to investigate structure and dynamics of nucleic acids at the atomic level and to gain insight into the physical chemistry behind.

Formation of Ultracold Molecules

Energy Technology Data Exchange (ETDEWEB)

Cote, Robin [Univ. of Connecticut, Storrs, CT (United States)

2016-01-28

Advances in our ability to slow down and cool atoms and molecules to ultracold temperatures have paved the way to a revolution in basic research on molecules. Ultracold molecules are sensitive of very weak interactions, even when separated by large distances, which allow studies of the effect of those interactions on the behavior of molecules. In this program, we have explored ways to form ultracold molecules starting from pairs of atoms that have already reached the ultracold regime. We devised methods that enhance the efficiency of ultracold molecule production, for example by tuning external magnetic fields and using appropriate laser excitations. We also investigates the properties of those ultracold molecules, especially their de-excitation into stable molecules. We studied the possibility of creating new classes of ultra-long range molecules, named macrodimers, thousand times more extended than regular molecules. Again, such objects are possible because ultra low temperatures prevent their breakup by collision. Finally, we carried out calculations on how chemical reactions are affected and modified at ultracold temperatures. Normally, reactions become less effective as the temperature decreases, but at ultracold temperatures, they can become very effective. We studied this counter-intuitive behavior for benchmark chemical reactions involving molecular hydrogen.

Magnetic quantum tunneling: insights from simple molecule-based magnets.

Science.gov (United States)

Hill, Stephen; Datta, Saiti; Liu, Junjie; Inglis, Ross; Milios, Constantinos J; Feng, Patrick L; Henderson, John J; del Barco, Enrique; Brechin, Euan K; Hendrickson, David N

2010-05-28

This perspectives article takes a broad view of the current understanding of magnetic bistability and magnetic quantum tunneling in single-molecule magnets (SMMs), focusing on three families of relatively simple, low-nuclearity transition metal clusters: spin S = 4 Ni(II)(4), Mn(III)(3) (S = 2 and 6) and Mn(III)(6) (S = 4 and 12). The Mn(III) complexes are related by the fact that they contain triangular Mn(III)(3) units in which the exchange may be switched from antiferromagnetic to ferromagnetic without significantly altering the coordination around the Mn(III) centers, thereby leaving the single-ion physics more-or-less unaltered. This allows for a detailed and systematic study of the way in which the individual-ion anisotropies project onto the molecular spin ground state in otherwise identical low- and high-spin molecules, thus providing unique insights into the key factors that control the quantum dynamics of SMMs, namely: (i) the height of the kinetic barrier to magnetization relaxation; and (ii) the transverse interactions that cause tunneling through this barrier. Numerical calculations are supported by an unprecedented experimental data set (17 different compounds), including very detailed spectroscopic information obtained from high-frequency electron paramagnetic resonance and low-temperature hysteresis measurements. Comparisons are made between the giant spin and multi-spin phenomenologies. The giant spin approach assumes the ground state spin, S, to be exact, enabling implementation of simple anisotropy projection techniques. This methodology provides a basic understanding of the concept of anisotropy dilution whereby the cluster anisotropy decreases as the total spin increases, resulting in a barrier that depends weakly on S. This partly explains why the record barrier for a SMM (86 K for Mn(6)) has barely increased in the 15 years since the first studies of Mn(12)-acetate, and why the tiny Mn(3) molecule can have a barrier approaching 60% of this

Secret-key and identification rates for biometric identification systems with protected templates

NARCIS (Netherlands)

Ignatenko, T.; Willems, F.M.J.

2010-01-01

In this paper we consider secret generation in biometric identification systems with protected templates. This problem is closely related to the study of the bio metric identification capacity [Willems et al., 2003] and [O’Sullivan and Sclmmid, 2002] and the common randomness generation scheme

Structure formation in bis(terpyridine) derivative adlayers: molecule-substrate versus molecule-molecule interactions.

Science.gov (United States)

Hoster, Harry E; Roos, Matthias; Breitruck, Achim; Meier, Christoph; Tonigold, Katrin; Waldmann, Thomas; Ziener, Ulrich; Landfester, Katharina; Behm, R Jürgen

2007-11-06

The influence of the substrate and the deposition conditions-vapor deposition versus deposition from solution-on the structures formed upon self-assembly of deposited bis(terpyridine) derivative (2,4'-BTP) monolayers on different hexagonal substrates, including highly oriented pyrolytic graphite (HOPG), Au(111), and (111)-oriented Ag thin films, was investigated by high-resolution scanning tunneling microscopy and by model calculations of the intermolecular energies and the lateral corrugation of the substrate-adsorbate interaction. Similar quasi-quadratic network structures with almost the same lattice constants obtained on all substrates are essentially identical to the optimum configuration expected from an optimization of the adlayer structure with C-H...N-type bridging bonds as a structure-determining factor, which underlines a key role of the intermolecular interactions in adlayer order. Slight distortions from the optimum values to form commensurate adlayer structures on the metal substrates and the preferential orientation of the adlayer with respect to the substrate are attributed to the substrate-adsorbate interactions, specifically, the lateral corrugation in the substrate-adsorbate interaction upon lateral displacement and rotation of the adsorbed BTP molecules. The fact that similar adlayer structures are obtained on HOPG under ultrahigh vacuum conditions (solid|gas interface) and on HOPG in trichlorobenzene (solid|liquid interface) indicates that the intermolecular interactions are not severely affected by the solvent.

Ethical issues in radiation protection

International Nuclear Information System (INIS)

Shrader-Frechette, K.; Persson, L.

1997-01-01

In this note the authors survey existing international radiation-protection recommendations of the ICRP, the IAEA, and the ILO. After outlining previous work on the ethics of radiation protection and risk assessment/management, the authors review ethical thinking on five key issues related to radiation protection and ethics. They formulate each of these five issues in terms of alternative ethical stances: (1) Equity vs. Efficiency, (2) Health vs. Economics, (3) Individual Rights vs. Societal Benefits, (4) Due Process vs. Necessary Sacrifice, and (5) Stakeholder Consent vs. Management Decisions (authors)

Protecting privacy in data release

CERN Document Server

Livraga, Giovanni

2015-01-01

This book presents a comprehensive approach to protecting sensitive information when large data collections are released by their owners. It addresses three key requirements of data privacy: the protection of data explicitly released, the protection of information not explicitly released but potentially vulnerable due to a release of other data, and the enforcement of owner-defined access restrictions to the released data. It is also the first book with a complete examination of how to enforce dynamic read and write access authorizations on released data, applicable to the emerging data outsou

Exotic helium molecules; Molecules exotiques d'helium

Energy Technology Data Exchange (ETDEWEB)

Portier, M

2007-12-15

We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

Thymosin Beta 4 protects mice from monocrotaline-induced pulmonary hypertension and right ventricular hypertrophy.

Directory of Open Access Journals (Sweden)

Chuanyu Wei

Full Text Available Pulmonary hypertension (PH is a progressive vascular disease of pulmonary arteries that impedes ejection of blood by the right ventricle. As a result there is an increase in pulmonary vascular resistance and pulmonary arterial pressure causing right ventricular hypertrophy (RVH and RV failure. The pathology of PAH involves vascular cell remodeling including pulmonary arterial endothelial cell (PAEC dysfunction and pulmonary arterial smooth muscle cell (PASMC proliferation. Current therapies are limited to reverse the vascular remodeling. Investigating a key molecule is required for development of new therapeutic intervention. Thymosin beta-4 (Tβ4 is a ubiquitous G-actin sequestering protein with diverse biological function and promotes wound healing and modulates inflammatory responses. However, it remains unknown whether Tβ4 has any protective role in PH. The purpose of this study is to evaluate the whether Tβ4 can be used as a vascular-protective agent. In monocrotaline (MCT-induced PH mouse model, we showed that mice treated with Tβ4 significantly attenuated the systolic pressure and RVH, compared to the MCT treated mice. Our data revealed for the first time that Tβ4 selectively targets Notch3-Col 3A-CTGF gene axis in preventing MCT-induced PH and RVH. Our study may provide pre-clinical evidence for Tβ4 and may consider as vasculo-protective agent for the treatment of PH induced RVH.

Key Management Strategies for Safeguards Authentication and Encryption

International Nuclear Information System (INIS)

Coram, M.; Hymel, R.; McDaniel, M.; Brotz, J.

2015-01-01

Management of cryptographic keys for the authentication and encryption of safeguards data can be the critical weak link in the practical implementation of information security. Within the safeguards community, there is the need to validate that data has not been modified at any point since generation and that it was generated by the monitoring node and not an imposter. In addition, there is the need for that data to be transmitted securely between the monitoring node and the monitoring party such that it cannot be intercepted and read while in transit. Encryption and digital signatures support the required confidentiality and authenticity but challenges exist in managing the cryptographic keys they require. Technologies developed at Sandia National Laboratories have evolved in their use of an associated key management strategy. The first generation system utilized a shared secret key for digital signatures. While fast and efficient, it required that a list of keys be maintained and protected. If control of the key was lost, fraudulent data could be made to look authentic. The second generation changed to support public key / private key cryptography. The key pair is generated by the system, the public key shared, and the private key held internally. This approach eliminated the need to maintain the list of keys. It also allows the public key to be provided to anyone needing to authenticate the data without allowing them to spoof data. A third generation system, currently under development, improves upon the public key / private key approach to address a potential man-in-the-middle attack related to the sharing of the public key. In a planned fourth generation system, secure key exchange protocols will distribute session keys for encryption, eliminating another fixed set of keys utilized by the technology and allowing for periodic renegotiation of keys for enhanced security. (author)

The status of molecules

International Nuclear Information System (INIS)

Barnes, T.; Oak Ridge National Lab., TN; Tennessee Univ., Knoxville, TN

1994-06-01

This report summarizes the experimental and theoretical status of hadronic molecules, which are weakly-bound states of two or more hadrons. We begin with a brief history of the subject and discuss a few good candidates, and then abstract some signatures for molecules which may be of interest in the classification of possible molecule states. Next we argue that a more general understanding of 2 → 2 hadron-hadron scattering amplitudes will be crucial for molecule searches, and discuss some of our recent work in this area. We conclude with a discussion of a few more recent molecule candidates (notably the f o (1710)) which are not well established as molecules but satisfy some of the expected signatures. (Author)

Solution processable organic polymers and small molecules for bulk-heterojunction solar cells: A review

International Nuclear Information System (INIS)

Sharma, G. D.

2011-01-01

Solution processed bulk heterojunction (BHJ) organic solar cells (OSCs) have gained wide interest in past few years and are established as one of the leading next generation photovoltaic technologies for low cost power production. Power conversion efficiencies up to 6% and 6.5% have been reported in the literature for single layer and tandem solar cells, respectively using conjugated polymers. A recent record efficiency about 8.13% with active area of 1.13 cm 2 has been reported. However Solution processable small molecules have been widely applied for photovoltaic (PV) devices in recent years because they show strong absorption properties, and they can be easily purified and deposited onto flexible substrates at low cost. Introducing different donor and acceptor groups to construct donor--acceptor (D--A) structure small molecules has proved to be an efficient way to improve the properties of organic solar cells (OSCs). The power conversion efficiency about 4.4 % has been reported for OSCs based on the small molecules. This review deals with the recent progress of solution processable D--A structure small molecules and discusses the key factors affecting the properties of OSCs based on D--A structure small molecules: sunlight absorption, charge transport and the energy level of the molecules.

The Role of Immunoglobulin Superfamily Cell Adhesion Molecules in Cancer Metastasis

Directory of Open Access Journals (Sweden)

Chee Wai Wong

2012-01-01

Full Text Available Metastasis is a major clinical problem and results in a poor prognosis for most cancers. The metastatic pathway describes the process by which cancer cells give rise to a metastatic lesion in a new tissue or organ. It consists of interconnecting steps all of which must be successfully completed to result in a metastasis. Cell-cell adhesion is a key aspect of many of these steps. Adhesion molecules belonging to the immunoglobulin superfamily (Ig-SF commonly play a central role in cell-cell adhesion, and a number of these molecules have been associated with cancer progression and a metastatic phenotype. Surprisingly, the contribution of Ig-SF members to metastasis has not received the attention afforded other cell adhesion molecules (CAMs such as the integrins. Here we examine the steps in the metastatic pathway focusing on how the Ig-SF members, melanoma cell adhesion molecule (MCAM, L1CAM, neural CAM (NCAM, leukocyte CAM (ALCAM, intercellular CAM-1 (ICAM-1 and platelet endothelial CAM-1 (PECAM-1 could play a role. Although much remains to be understood, this review aims to raise the profile of Ig-SF members in metastasis formation and prompt further research that could lead to useful clinical outcomes.

Computational analysis of protein-protein interfaces involving an alpha helix: insights for terphenyl-like molecules binding.

Science.gov (United States)

Isvoran, Adriana; Craciun, Dana; Martiny, Virginie; Sperandio, Olivier; Miteva, Maria A

2013-06-14

Protein-Protein Interactions (PPIs) are key for many cellular processes. The characterization of PPI interfaces and the prediction of putative ligand binding sites and hot spot residues are essential to design efficient small-molecule modulators of PPI. Terphenyl and its derivatives are small organic molecules known to mimic one face of protein-binding alpha-helical peptides. In this work we focus on several PPIs mediated by alpha-helical peptides. We performed computational sequence- and structure-based analyses in order to evaluate several key physicochemical and surface properties of proteins known to interact with alpha-helical peptides and/or terphenyl and its derivatives. Sequence-based analysis revealed low sequence identity between some of the analyzed proteins binding alpha-helical peptides. Structure-based analysis was performed to calculate the volume, the fractal dimension roughness and the hydrophobicity of the binding regions. Besides the overall hydrophobic character of the binding pockets, some specificities were detected. We showed that the hydrophobicity is not uniformly distributed in different alpha-helix binding pockets that can help to identify key hydrophobic hot spots. The presence of hydrophobic cavities at the protein surface with a more complex shape than the entire protein surface seems to be an important property related to the ability of proteins to bind alpha-helical peptides and low molecular weight mimetics. Characterization of similarities and specificities of PPI binding sites can be helpful for further development of small molecules targeting alpha-helix binding proteins.

Key Developments in Ionic Liquid Crystals.

Science.gov (United States)

Alvarez Fernandez, Alexandra; Kouwer, Paul H J

2016-05-16

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Key Developments in Ionic Liquid Crystals

Directory of Open Access Journals (Sweden)

Alexandra Alvarez Fernandez

2016-05-01

Full Text Available Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Strategy to discover diverse optimal molecules in the small molecule universe.

Science.gov (United States)

Rupakheti, Chetan; Virshup, Aaron; Yang, Weitao; Beratan, David N

2015-03-23

The small molecule universe (SMU) is defined as a set of over 10(60) synthetically feasible organic molecules with molecular weight less than ∼500 Da. Exhaustive enumerations and evaluation of all SMU molecules for the purpose of discovering favorable structures is impossible. We take a stochastic approach and extend the ACSESS framework ( Virshup et al. J. Am. Chem. Soc. 2013 , 135 , 7296 - 7303 ) to develop diversity oriented molecular libraries that can generate a set of compounds that is representative of the small molecule universe and that also biases the library toward favorable physical property values. We show that the approach is efficient compared to exhaustive enumeration and to existing evolutionary algorithms for generating such libraries by testing in the NKp fitness landscape model and in the fully enumerated GDB-9 chemical universe containing 3 × 10(5) molecules.

New attitudes key to progress in Malawi, Cameroon | IDRC ...

International Development Research Centre (IDRC) Digital Library (Canada)

2011-11-08

Nov 8, 2011 ... New attitudes key to progress in Malawi, Cameroon ... in Malawi — good laws protecting women's rights — but they are not working. Why? ... Colonial rule — first by the Germans and later the French and British — brought in a ...

Chemical protection against ionizing radiation

International Nuclear Information System (INIS)

Livesey, J.C.; Reed, D.J.

1987-01-01

Over 40 years have passed since the research of the Manhattan Project suggested the possibility of chemical protection against ionizing radiation. During that time, much has been learned about the nature of radiation-induced injury and the factors governing the expression of that injury. Thousands of compounds have been tested for radioprotective efficacy, and numerous theories have been proposed to account for these actions. The literature on chemical radioprotection is large. In this article, the authors consider several of the mechanisms by which chemicals may protect against radiation injury. They have chosen to accent this view of radioprotector research as opposed to that research geared toward developing specific molecules as protective agents because they feel that such an approach is more beneficial in stimulating research of general applicability. This paper describes the matrix of biological factors upon which an exogenous radioprotector is superimposed, and examines evidence for and against various mechanisms by which these agents may protect biological systems against ionizing radiation. It concludes with a brief outlook for research in chemical radioprotection

Questions concerning radiation protection in the field of radiometry

International Nuclear Information System (INIS)

Gruen, W.; Quednau, F.; Wels, Ch.

1987-01-01

Based on legal regulations, guidelines, and standards valid in the German Democratic Republic 105 questions concerning radiation protection are answered covering subjects indicated by the following key words and headings: radiometric gages, radiation protection measures, working within protected areas, legal provisions, responsible staff member, radiation protection officer, operating personnel, radiation protection instructions, safe keeping of radiation sources, leak testing, unusual occurrence, transport of radioactive materials, and ceasing of operation

Multiply excited molecules produced by photon and electron interactions

International Nuclear Information System (INIS)

Odagiri, T.; Kouchi, N.

2006-01-01

The photon and electron interactions with molecules resulting in the formation of multiply excited molecules and the subsequent decay are subjects of great interest because the independent electron model and Born-Oppenheimer approximation are much less reliable for the multiply excited states of molecules than for the ground and lower excited electronic states. We have three methods to observe and investigate multiply excited molecules: 1) Measurements of the cross sections for the emission of fluorescence emitted by neutral fragments in the photoexcitation of molecules as a function of incident photon energy [1-3], 2) Measurements of the electron energy-loss spectra tagged with the fluorescence photons emitted by neutral fragments [4], 3) Measurements of the cross sections for generating a pair of photons in absorption of a single photon by a molecule as a function of incident photon energy [5-7]. Multiply excited states degenerate with ionization continua, which make a large contribution in the cross section curve involving ionization processes. The key point of our methods is hence that we measure cross sections free from ionization. The feature of multiply excited states is noticeable in such a cross section curve. Recently we have measured: i) the cross sections for the emission of the Lyman- fluorescence in the photoexcitation of CH 4 as a function of incident photon energy in the range 18-51 eV, ii) the electron energy-loss spectrum of CH 4 tagged with the Lyman-photons at 80 eV incident electron energy and 10 electron scattering angle in the range of the energy loss 20-45 eV, in order to understand the formation and decay of the doubly excited methane in photon and electron interactions. [8] The results are summarized in this paper and the simultaneous excitation of two electrons by electron interaction is compared with that by photon interaction in terms of the oscillator strength. (authors)

Biopolymers for sample collection, protection, and preservation.

Science.gov (United States)

Sorokulova, Iryna; Olsen, Eric; Vodyanoy, Vitaly

2015-07-01

One of the principal challenges in the collection of biological samples from air, water, and soil matrices is that the target agents are not stable enough to be transferred from the collection point to the laboratory of choice without experiencing significant degradation and loss of viability. At present, there is no method to transport biological samples over considerable distances safely, efficiently, and cost-effectively without the use of ice or refrigeration. Current techniques of protection and preservation of biological materials have serious drawbacks. Many known techniques of preservation cause structural damages, so that biological materials lose their structural integrity and viability. We review applications of a novel bacterial preservation process, which is nontoxic and water soluble and allows for the storage of samples without refrigeration. The method is capable of protecting the biological sample from the effects of environment for extended periods of time and then allows for the easy release of these collected biological materials from the protective medium without structural or DNA damage. Strategies for sample collection, preservation, and shipment of bacterial, viral samples are described. The water-soluble polymer is used to immobilize the biological material by replacing the water molecules within the sample with molecules of the biopolymer. The cured polymer results in a solid protective film that is stable to many organic solvents, but quickly removed by the application of the water-based solution. The process of immobilization does not require the use of any additives, accelerators, or plastifiers and does not involve high temperature or radiation to promote polymerization.

Laboratory studies of ion-molecule reactions and interstellar chemistry

International Nuclear Information System (INIS)

Koyano, Inosuke

1989-01-01

Several types of laboratory studies have been performed on ion-molecule reactions relevant to the formation of the interstellar molecules. Special emphasis is placed on the formation, structure, and reactivity of the C 3 H 3 + ions, which are believed to play a key role in interstellar chemistry. When these ions are produced by the reaction of C 3 H 4+ with C 3 H 4 in a beam-gas arrangement, their times-of-flight (TOF) show abnormally broad distributions regardless of the sources of the reactant C 3 H 4 + ion (photoionization of allene, propyne, the cyclopropene) and the nature of the neutral reactant, while all other product ions from the same reaction show sharp TOF distributions. On the other hand, all C 3 H 3 + ions produced by unimolecular decomposition of energetic C 3 H 4 + ions show sharp TOF distribution. The peculiarity of the C 3 H 3 + ions manifested in these and other experiments is discussed in conjunction with interstellar chemistry

Secure quantum key distribution using squeezed states

International Nuclear Information System (INIS)

Gottesman, Daniel; Preskill, John

2001-01-01

We prove the security of a quantum key distribution scheme based on transmission of squeezed quantum states of a harmonic oscillator. Our proof employs quantum error-correcting codes that encode a finite-dimensional quantum system in the infinite-dimensional Hilbert space of an oscillator, and protect against errors that shift the canonical variables p and q. If the noise in the quantum channel is weak, squeezing signal states by 2.51 dB (a squeeze factor e r =1.34) is sufficient in principle to ensure the security of a protocol that is suitably enhanced by classical error correction and privacy amplification. Secure key distribution can be achieved over distances comparable to the attenuation length of the quantum channel

Resilience from coastal protection.

Science.gov (United States)

Ewing, Lesley C

2015-10-28

Coastal areas are important residential, commercial and industrial areas; but coastal hazards can pose significant threats to these areas. Shoreline/coastal protection elements, both built structures such as breakwaters, seawalls and revetments, as well as natural features such as beaches, reefs and wetlands, are regular features of a coastal community and are important for community safety and development. These protection structures provide a range of resilience to coastal communities. During and after disasters, they help to minimize damages and support recovery; during non-disaster times, the values from shoreline elements shift from the narrow focus on protection. Most coastal communities have limited land and resources and few can dedicate scarce resources solely for protection. Values from shore protection can and should expand to include environmental, economic and social/cultural values. This paper discusses the key aspects of shoreline protection that influence effective community resilience and protection from disasters. This paper also presents ways that the economic, environmental and social/cultural values of shore protection can be evaluated and quantified. It presents the Coastal Community Hazard Protection Resilience (CCHPR) Index for evaluating the resilience capacity to coastal communities from various protection schemes and demonstrates the use of this Index for an urban beach in San Francisco, CA, USA. © 2015 The Author(s).

The summarize of the technique about proactive network security protection

International Nuclear Information System (INIS)

Liu Baoxu; Li Xueying; Cao Aijuan; Yu Chuansong; Xu Rongsheng

2003-01-01

The proactive protection measures and the traditional passive security protection tools are complementarities each other. It also can supply the conventional network security protection system and enhance its capability of the security protection. Based upon sorts of existing network security technologies, this article analyses and summarizes the technologies, functions and the development directions of some key proactive network security protection tools. (authors)

Machine Learning Reveals a Non-Canonical Mode of Peptide Binding to MHC class II Molecules

DEFF Research Database (Denmark)

Andreatta, Massimo; Jurtz, Vanessa Isabell; Kaever, Thomas

2017-01-01

binding motif with a non-canonical binding core of length different from nine. This previously undescribed mode of peptide binding to MHCII molecules gives a more complete picture of peptide presentation by MHCII and allows us to model more accurately this event. This article is protected by copyright...

Biological Nanopores: Confined Spaces for Electrochemical Single-Molecule Analysis.

Science.gov (United States)

Cao, Chan; Long, Yi-Tao

2018-02-20

, we develop an integrated current measurement system and an accurate data processing method for nanopore sensing. The unique geometric structure of a biological nanopore offers a distinct advantage as a nanosensor for single-molecule sensing. The construction of the pore entrance is responsible for capturing the target molecule, while the lumen region determines the translocation process of the single molecule. Since the capture of the target molecule is predominantly diffusion-limited, it is expected that the capture ability of the nanopore toward the target analyte could be effectively enhanced by site-directed mutations of key amino acids with desirable groups. Additionally, changing the side chains inside the wall of the biological nanopore could optimize the geometry of the pore and realize an optimal interaction between the single-molecule interface and the analyte. These improvements would allow for high spatial and current resolution of nanopore sensors, which would ensure the possibility of dynamic study of single biomolecules, including their metastable conformations, charge distributions, and interactions. In the future, data analysis with powerful algorithms will make it possible to automatically and statistically extract detailed information while an analyte translocates through the pore. We conclude that these improvements could have tremendous potential applications for nanopore sensing in the near future.

A Forward Authentication Key Management Scheme for Heterogeneous Sensor Networks

Directory of Open Access Journals (Sweden)

Huang Jen-Yan

2011-01-01

Full Text Available Key encryption technology is a basic technique for protecting the secrecy of transmitted data among sensor nodes in wireless sensor networks. However, sensor nodes are inherently limited by insufficient hardware resources such as memory capacity and battery lifetime. As a result, few current key management schemes are appropriate for wireless sensor networks. This paper proposes a new key management method that uses dynamic key management schemes for heterogeneous sensor networks. The proposed scheme loads a hash function into the base station, cluster heads, and sensor nodes. The cluster heads and sensor nodes then generate their own keychains to provide forward authentication in case of key changes, security breaches, key changes due to security breaches. The cluster heads and sensor nodes establish pairwise keys to ensure transmission secrecy. The proposed scheme decreases the number of keys required for sensor nodes and cluster heads and is robust to the following attacks: guessing attacks, replay attacks, man-in-the-middle attacks, node capture attacks, and denial-of-service attacks.

Identification of glucocorticoid-induced leucine zipper as a key regulator of tumor cell proliferation in epithelial ovarian cancer

Directory of Open Access Journals (Sweden)

Fernandez Hervé

2009-10-01

Full Text Available Abstract Background Little is known about the molecules that contribute to tumor progression of epithelial ovarian cancer (EOC, currently a leading cause of mortality from gynecological malignancies. Glucocorticoid-Induced Leucine Zipper (GILZ, an intracellular protein widely expressed in immune tissues, has been reported in epithelial tissues and controls some of key signaling pathways involved in tumorigenesis. However, there has been no report on GILZ in EOC up to now. The objectives of the current study were to examine the expression of GILZ in EOC and its effect on tumor cell proliferation. Results GILZ expression was measured by immunohistochemical staining in tissue sections from 3 normal ovaries, 7 benign EOC and 50 invasive EOC. GILZ was not detected on the surface epithelium of normal ovaries and benign tumors. In contrast, it was expressed in the cytoplasm of tumor cells in 80% EOC specimens. GILZ immunostaining scores correlated positively to the proliferation marker Ki-67 (Spearman test in univariate analysis, P P Conclusion The present study is the first to identify GILZ as a molecule produced by ovarian cancer cells that promotes cell cycle progression and proliferation. Our findings clearly indicate that GILZ activates AKT, a crucial signaling molecule in tumorigenesis. GILZ thus appears as a potential key molecule in EOC.

Key-Insulated Undetachable Digital Signature Scheme and Solution for Secure Mobile Agents in Electronic Commerce

Directory of Open Access Journals (Sweden)

Yang Shi

2016-01-01

Full Text Available Considering the security of both the customers’ hosts and the eShops’ servers, we introduce the idea of a key-insulated undetachable digital signature, enabling mobile agents to generate undetachable digital signatures on remote hosts with the key-insulated property of the original signer’s signing key. From the theoretical perspective, we provide the formal definition and security notion of a key-insulated undetachable digital signature. From the practical perspective, we propose a concrete scheme to secure mobile agents in electronic commerce. The scheme is mainly focused on protecting the signing key from leakage and preventing the misuse of the signature algorithm on malicious servers. Agents do not carry the signing key when they generate digital signatures on behalf of the original signer, so the key is protected on remote servers. Furthermore, if a hacker gains the signing key of the original signer, the hacker is still unable to forge a signature for any time period other than the key being accessed. In addition, the encrypted function is combined with the original signer’s requirement to prevent the misuse of signing algorithm. The scheme is constructed on gap Diffie–Hellman groups with provable security, and the performance testing indicates that the scheme is efficient.

Resilience in homeless youth: the key role of self-esteem.

Science.gov (United States)

Kidd, Sean; Shahar, Golan

2008-04-01

This study examined the protective role of self-esteem, social involvement, and secure attachment among homeless youths. These protective factors were examined as they ameliorate risks among 208 homeless youths surveyed in New York City and Toronto. Both mental and physical health indicators were employed in this study, including loneliness, feeling trapped, suicidal ideation, subjective health status, and substance use. Self-esteem emerged as a key protective factor, predicting levels of loneliness, feeling trapped, and suicide ideation, and buffering against the deleterious effect of fearful attachment on loneliness. Findings highlight the role of the self-concept in risk and resilience among homeless youth. Copyright 2008 APA, all rights reserved.

Dynamics of Activated Molecules

Energy Technology Data Exchange (ETDEWEB)

Mullin, Amy S. [Univ. of Maryland, College Park, MD (United States)

2016-11-16

Experimental studies have been performed to investigate the collisional energy transfer processes of gas-phase molecules that contain large amounts of internal energy. Such molecules are prototypes for molecules under high temperature conditions relevant in combustion and information about their energy transfer mechanisms is needed for a detailed understanding and modeling of the chemistry. We use high resolution transient IR absorption spectroscopy to measure the full, nascent product distributions for collisions of small bath molecules that relax highly vibrationally excited pyrazine molecules with E=38000 cm-1 of vibrational energy. To perform these studies, we developed new instrumentation based on modern IR light sources to expand our experimental capabilities to investigate new molecules as collision partners. This final report describes our research in four areas: the characterization of a new transient absorption spectrometer and the results of state-resolved collision studies of pyrazine(E) with HCl, methane and ammonia. Through this research we have gained fundamental new insights into the microscopic details of relatively large complex molecules at high energy as they undergo quenching collisions and redistribute their energy.

Hepatic JAK2 protects against atherosclerosis through circulating IGF-1.

Science.gov (United States)

Sivasubramaniyam, Tharini; Schroer, Stephanie A; Li, Angela; Luk, Cynthia T; Shi, Sally Yu; Besla, Rickvinder; Dodington, David W; Metherel, Adam H; Kitson, Alex P; Brunt, Jara J; Lopes, Joshua; Wagner, Kay-Uwe; Bazinet, Richard P; Bendeck, Michelle P; Robbins, Clinton S; Woo, Minna

2017-07-20

Atherosclerosis is considered both a metabolic and inflammatory disease; however, the specific tissue and signaling molecules that instigate and propagate this disease remain unclear. The liver is a central site of inflammation and lipid metabolism that is critical for atherosclerosis, and JAK2 is a key mediator of inflammation and, more recently, of hepatic lipid metabolism. However, precise effects of hepatic Jak2 on atherosclerosis remain unknown. We show here that hepatic Jak2 deficiency in atherosclerosis-prone mouse models exhibited accelerated atherosclerosis with increased plaque macrophages and decreased plaque smooth muscle cell content. JAK2's essential role in growth hormone signalling in liver that resulted in reduced IGF-1 with hepatic Jak2 deficiency played a causal role in exacerbating atherosclerosis. As such, restoring IGF-1 either pharmacologically or genetically attenuated atherosclerotic burden. Together, our data show hepatic Jak2 to play a protective role in atherogenesis through actions mediated by circulating IGF-1 and, to our knowledge, provide a novel liver-centric mechanism in atheroprotection.

Heterobifunctional crosslinkers for tethering single ligand molecules to scanning probes

International Nuclear Information System (INIS)

Riener, Christian K.; Kienberger, Ferry; Hahn, Christoph D.; Buchinger, Gerhard M.; Egwim, Innocent O.C.; Haselgruebler, Thomas; Ebner, Andreas; Romanin, Christoph; Klampfl, Christian; Lackner, Bernd; Prinz, Heino; Blaas, Dieter; Hinterdorfer, Peter; Gruber, Hermann J.

2003-01-01

Single molecule recognition force microscopy (SMRFM) is a versatile atomic force microscopy (AFM) method to probe specific interactions of cognitive molecules on the single molecule level. It allows insights to be gained into interaction potentials and kinetic barriers and is capable of mapping interaction sites with nm positional accuracy. These applications require a ligand to be attached to the AFM tip, preferably by a distensible poly(ethylene glycol) (PEG) chain between the measuring tip and the ligand molecule. The PEG chain greatly facilitates specific binding of the ligand to immobile receptor sites on the sample surface. The present study contributes to tip-PEG-ligand tethering in three ways: (i) a convenient synthetic route was found to prepare NH 2 -PEG-COOH which is the key intermediate for long heterobifunctional crosslinkers; (ii) a variety of heterobifunctional PEG derivatives for tip-PEG-ligand linking were prepared from NH 2 -PEG-COOH; (iii) in particular, a new PEG crosslinker with one thiol-reactive end and one terminal nitrilotriacetic acid (NTA) group was synthesized and successfully used to tether His 6 -tagged protein molecules to AFM tips via noncovalent NTA-Ni 2+ -His 6 bridges. The new crosslinker was applied to link a recombinant His 6 -tagged fragment of the very-low density lipoprotein receptor to the AFM tip whereupon specific docking to the capsid of human rhinovirus particles was observed by force microscopy. In a parallel study, the specific interaction of the small GTPase Ran with the nuclear import receptor importin β1 was studied in detail by SMRFM, using the new crosslinker to link His 6 -tagged Ran to the measuring tip [Nat. Struct. Biol. (2003), 10, 553-557

Guarding America: Security Guards and U.S. Critical Infrastructure Protection

National Research Council Canada - National Science Library

Parfomak, Paul W

2004-01-01

The Bush Administration's 2003 National Strategy for the Physical Protection of Critical Infrastructures and Key Assets indicates that security guards are an important source of protection for critical facilities...

Institutional Data Management in Higher Education. ECAR Key Findings

Science.gov (United States)

Yanosky, Ronald

2009-01-01

This document presents the key findings from the 2009 ECAR (EDUCAUSE Center for Applied Research) study of institutional data management, which examines the policies and practices by which higher education institutions effectively collect, protect, and use digital information assets to meet academic and business needs. Importantly, it also…

System level ESD protection

CERN Document Server

Vashchenko, Vladislav

2014-01-01

This book addresses key aspects of analog integrated circuits and systems design related to system level electrostatic discharge (ESD) protection.  It is an invaluable reference for anyone developing systems-on-chip (SoC) and systems-on-package (SoP), integrated with system-level ESD protection. The book focuses on both the design of semiconductor integrated circuit (IC) components with embedded, on-chip system level protection and IC-system co-design. The readers will be enabled to bring the system level ESD protection solutions to the level of integrated circuits, thereby reducing or completely eliminating the need for additional, discrete components on the printed circuit board (PCB) and meeting system-level ESD requirements. The authors take a systematic approach, based on IC-system ESD protection co-design. A detailed description of the available IC-level ESD testing methods is provided, together with a discussion of the correlation between IC-level and system-level ESD testing methods. The IC-level ESD...

Electron-molecule collisions

International Nuclear Information System (INIS)

Shimamura, I.; Takayanagi, K.

1984-01-01

The study of collision processes plays an important research role in modern physics. Many significant discoveries have been made by means of collision experiments. Based on theoretical, experimental, and computational studies, this volume presents an overview detailing the basic processes of electron-molecule collisions. The editors have collected papers-written by a group of international experts-that consider a diverse range of phenomena occurring in electronmolecule collisions. The volume discusses first the basic formulation for scattering problems and then gives an outline of the physics of electron-molecule collisions. The main topics covered are rotational transitions, vibrational transitions, dissociation of molecules in slow collisions, the electron-molecule collision as a spectroscopic tool for studying molecular electronic structures, and experimental and computational techniques for determining the cross sections. These well-referenced chapters are self-contained and can be read independently or consecutively. Authoritative and up-to-date, Electron-Molecule Collisions is a useful addition to the libraries of students and researchers in the fields of atomic, molecular, and chemical physics, and physical chemistry

Considerable improvement in the stability of solution processed small molecule OLED by annealing

Energy Technology Data Exchange (ETDEWEB)

Mao Guilin [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Wu Zhaoxin, E-mail: zhaoxinwu@mail.xjtu.edu.cn [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); He Qiang [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Department of UAV, Wuhan Ordnance Noncommissioned Officers Academy, Wuhan, 430075 (China); Jiao Bo; Xu Guojin; Hou Xun [Key Laboratory of Photonics Technology for Information, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an, 710049 (China); Chen Zhijian; Gong Qihuang [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing, 100871 (China)

2011-06-15

We investigated the annealing effect on solution processed small organic molecule organic films, which were annealed with various conditions. It was found that the densities of the spin-coated (SC) films increased and the surface roughness decreased as the annealing temperature rose. We fabricated corresponding organic light emitting diodes (OLEDs) by spin coating on the same annealing conditions. The solution processed OLEDs show the considerable efficiency and stability, which were prior or equivalent to the vacuum-deposited (VD) counterparts. Our research shows that annealing process plays a key role in prolonging the lifetime of solution processed small molecule OLEDs, and the mechanism for the improvement of the device performance upon annealing was also discussed.

Fast pulses and slow atoms: making microKelvin molecules using femtosecond lasers

Science.gov (United States)

Walmsley, Ian

2008-05-01

We discuss a general approach to the formation of ultracold ground state molecules by synthesis from pairs of cold atoms using shaped ultrashort optical pulses. This method combines an effective and widely applicable control technology to the problem of preparing molecules is the ground state of all their degrees of freedom. The broad bandwidth of femtosecond pulses provides and number of options for removing energy from a pair of colliding atoms, and binding them with little or no vibrational energy. We shall give examples of possible strategies, and report on experiments demonstrating photoassocation using coherent control, and measuring wavepacket dynamics by femtosecond pump probe molecular ionization. Prospects for stabilizing the molecules by protecting them from further collisions, and for increasing the range of internuclear separations that can be associated will be pointed out. This work is funded by the UK EPSRC, and has contributions from J. Petrovic, A. Wyatt, A. Dicks, D. McCabe, D. England, M. Friedman, H. Martay, T. Koehler, C. Foot and collaborations with F. Masnou-Seeuws and J. Mur-Petit.

Passive fire protection role and evolutions

Energy Technology Data Exchange (ETDEWEB)

Cerosky, Tristan [NUVIA (France); Perdrix, Johan [NUVIA Protection (France)

2015-12-15

Major incidents associated with nuclear power plants often invoke a re-examination of key safety barriers. Fire hazard, in particular, is a key concern for safe operation of nuclear power plants given its propensity to damage safety systems which could ultimately lead to radioactive release into the atmosphere. In the recent past, events such as the Fukushima disaster have led to an industry-wide push to improve nuclear safety arrangements. As part of these measures, upgrading of fire safety systems has received significant attention. In addition to the inherent intricacies associated with such a complex undertaking, factors such as frequent changes in the national and European fire regulations also require due attention while formulating a fire protection strategy. This paper will highlight some salient aspects underpinning an effective fire protection strategy. This will involve: A) A comprehensive introduction to the different aspects of fire safety (namely prevention, containment and mitigation) supported by a review of the development of the RCC-I from 1993 to 1997 editions and the ETC-F (AFCEN codes used by EDF in France). B) Development of the fire risk analysis methodology and the different functions of passive fire protection within this method involving confinement and protection of safety-related equipment. C) A review of the benefits of an effective passive fire protection strategy, alongside other arrangements (such as active fire protection) to a nuclear operator in term of safety and cost savings. It is expected that the paper will provide nuclear operators useful guidelines for strengthening existing fire protection systems.

Nano-fabrication of molecular electronic junctions by targeted modification of metal-molecule bonds

Science.gov (United States)

Jafri, S. Hassan M.; Löfås, Henrik; Blom, Tobias; Wallner, Andreas; Grigoriev, Anton; Ahuja, Rajeev; Ottosson, Henrik; Leifer, Klaus

2015-09-01

Reproducibility, stability and the coupling between electrical and molecular properties are central challenges in the field of molecular electronics. The field not only needs devices that fulfill these criteria but they also need to be up-scalable to application size. In this work, few-molecule based electronics devices with reproducible electrical characteristics are demonstrated. Our previously reported 5 nm gold nanoparticles (AuNP) coated with ω-triphenylmethyl (trityl) protected 1,8-octanedithiol molecules are trapped in between sub-20 nm gap spacing gold nanoelectrodes forming AuNP-molecule network. When the trityl groups are removed, reproducible devices and stable Au-thiol junctions are established on both ends of the alkane segment. The resistance of more than 50 devices is reduced by orders of magnitude as well as a reduction of the spread in the resistance histogram is observed. By density functional theory calculations the orders of magnitude decrease in resistance can be explained and supported by TEM observations thus indicating that the resistance changes and strongly improved resistance spread are related to the establishment of reproducible and stable metal-molecule bonds. The same experimental sequence is carried out using 1,6-hexanedithiol functionalized AuNPs. The average resistances as a function of molecular length, demonstrated herein, are comparable to the one found in single molecule devices.

Raman scattering mediated by neighboring molecules

Science.gov (United States)

Williams, Mathew D.; Bradshaw, David S.; Andrews, David L.

2016-05-01

Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process.

Raman scattering mediated by neighboring molecules

Energy Technology Data Exchange (ETDEWEB)

Williams, Mathew D.; Bradshaw, David S.; Andrews, David L., E-mail: david.andrews@physics.org [School of Chemistry, University of East Anglia, Norwich NR4 7TJ (United Kingdom)

2016-05-07

Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process.

Exotic helium molecules; Molecules exotiques d'helium

Energy Technology Data Exchange (ETDEWEB)

Portier, M

2007-12-15

We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

Synchronization in Quantum Key Distribution Systems

Directory of Open Access Journals (Sweden)

Anton Pljonkin

2017-10-01

Full Text Available In the description of quantum key distribution systems, much attention is paid to the operation of quantum cryptography protocols. The main problem is the insufficient study of the synchronization process of quantum key distribution systems. This paper contains a general description of quantum cryptography principles. A two-line fiber-optic quantum key distribution system with phase coding of photon states in transceiver and coding station synchronization mode was examined. A quantum key distribution system was built on the basis of the scheme with automatic compensation of polarization mode distortions. Single-photon avalanche diodes were used as optical radiation detecting devices. It was estimated how the parameters used in quantum key distribution systems of optical detectors affect the detection of the time frame with attenuated optical pulse in synchronization mode with respect to its probabilistic and time-domain characteristics. A design method was given for the process that detects the time frame that includes an optical pulse during synchronization. This paper describes the main quantum communication channel attack methods by removing a portion of optical emission. This paper describes the developed synchronization algorithm that takes into account the time required to restore the photodetector’s operation state after the photon has been registered during synchronization. The computer simulation results of the developed synchronization algorithm were analyzed. The efficiency of the developed algorithm with respect to synchronization process protection from unauthorized gathering of optical emission is demonstrated herein.

A new two-round dynamic authenticated contributory group key ...

Indian Academy of Sciences (India)

1Department of Computer Science, S V K P and Dr K S R Arts and Science College, ... curve key of a given length provides the same level of security as a 1,024-bit ...... Kwon T, Cheon J H, Kim Y and Lee J 2006 Privacy protection in PKIs: A ...

Identification of small molecule inhibitors of Pseudomonas aeruginosa exoenzyme S using a yeast phenotypic screen.

Directory of Open Access Journals (Sweden)

Anthony Arnoldo

2008-02-01

Full Text Available Pseudomonas aeruginosa is an opportunistic human pathogen that is a key factor in the mortality of cystic fibrosis patients, and infection represents an increased threat for human health worldwide. Because resistance of Pseudomonas aeruginosa to antibiotics is increasing, new inhibitors of pharmacologically validated targets of this bacterium are needed. Here we demonstrate that a cell-based yeast phenotypic assay, combined with a large-scale inhibitor screen, identified small molecule inhibitors that can suppress the toxicity caused by heterologous expression of selected Pseudomonas aeruginosa ORFs. We identified the first small molecule inhibitor of Exoenzyme S (ExoS, a toxin involved in Type III secretion. We show that this inhibitor, exosin, modulates ExoS ADP-ribosyltransferase activity in vitro, suggesting the inhibition is direct. Moreover, exosin and two of its analogues display a significant protective effect against Pseudomonas infection in vivo. Furthermore, because the assay was performed in yeast, we were able to demonstrate that several yeast homologues of the known human ExoS targets are likely ADP-ribosylated by the toxin. For example, using an in vitro enzymatic assay, we demonstrate that yeast Ras2p is directly modified by ExoS. Lastly, by surveying a collection of yeast deletion mutants, we identified Bmh1p, a yeast homologue of the human FAS, as an ExoS cofactor, revealing that portions of the bacterial toxin mode of action are conserved from yeast to human. Taken together, our integrated cell-based, chemical-genetic approach demonstrates that such screens can augment traditional drug screening approaches and facilitate the discovery of new compounds against a broad range of human pathogens.

Spins of adsorbed molecules investigated by the detection of Kondo resonance

Science.gov (United States)

Komeda, Tadahiro

2014-12-01

Surface magnetism has been one of the platforms to explore the magnetism in low dimensions. It is also a key component for the development of quantum information processes, which utilizes the spin degree of freedom. The Kondo resonance is a phenomenon that is caused by an interaction between an isolated spin and conduction electrons. First observed in the 1930s as an anomalous increase in the low-temperature resistance of metals embedded with magnetic atoms, the Kondo physics mainly studied the effects of bulk magnetic impurities in the resistivity. In the last 15 years it has undergone a revival by a scanning tunneling microscope (STM) which enables the measurement of the Kondo resonance at surfaces using an atomic scale point contact. The detection of the Kondo resonance can be a powerful tool to explore surface magnetism. In this article, I review recent studies of the surface spin of adsorbed molecules by the detection of the Kondo resonance. Researches on metal phthalocyanine (MPc) and porphyrin molecules will be examined. In addition, the Kondo resonance for double-decker lanthanoide Pc molecules will be discussed. Some of the double-decker Pc molecules show single-molecule magnet (SMM) behavior, which attracts attention as a material for electronic devices. For both classes, the ligand plays a crucial role in determining the parameters of the Kondo resonance, such as the Kondo temperature and the change of the shape from peak to Fano-dip. In addition, the spin in delocalized molecular orbital forms the Kondo resonance, which shows significant differences from the Kondo resonance formed by the metal spins. Since molecular orbital can be tuned in a flexible manner by the design of the molecule, the Kondo resonance formed by delocalized molecular orbital might expand the knowledge of this field.

40 CFR 370.3 - Which section contains the definitions of the key words used in this part?

Science.gov (United States)

2010-07-01

... of the key words used in this part? 370.3 Section 370.3 Protection of Environment ENVIRONMENTAL... definitions of the key words used in this part? The definitions of key words used in this part are in § 370.66. It is important to read the definitions for key words because the definition explains the word's...

[Research on the emission spectrum of NO molecule's γ-band system by corona discharge].

Science.gov (United States)

Zhai, Xiao-dong; Ding, Yan-jun; Peng, Zhi-min; Luo, Rui

2012-05-01

The optical emission spectrum of the gamma-band system of NO molecule, A2 sigma+ --> X2 pi(r), has been analyzed and calculated based on the energy structure of NO molecule' doublet states. By employing the theory of diatomic molecular Spectra, some key parameters of equations for the radiative transition intensity were evaluated theoretically, including the potentials of the doublet states of NO molecule's upper and lower energy levels, the electronic transition moments calculated by using r-centroid approximation method, and the Einstein coefficient of different vibrational and rotational levels. The simulated spectrum of the gamma-band system was calculated as a function of different vibrational and rotational temperature. Compared to the theoretical spectroscopy, the measured results were achieved from corona discharge experiments of NO and N2. The vibrational and rotational temperatures were determined approximately by fitting the measured spectral intensities with the calculated ones.

Impact of Anchoring Groups on Ballistic Transport: Single Molecule vs Monolayer Junctions

Science.gov (United States)

2015-01-01

Tuning the transport properties of molecular junctions by chemically modifying the molecular structure is one of the key challenges for advancing the field of molecular electronics. In the present contribution, we investigate current–voltage characteristics of differently linked metal–molecule–metal systems that comprise either a single molecule or a molecular assembly. This is achieved by employing density functional theory in conjunction with a Green’s function approach. We show that the conductance of a molecular system with a specific anchoring group is fundamentally different depending on whether a single molecule or a continuous monolayer forms the junction. This is a consequence of collective electrostatic effects that arise from dipolar elements contained in the monolayer and from interfacial charge rearrangements. As a consequence of these collective effects, the “ideal” choice for an anchoring group is clearly different for monolayer and single molecule devices. A particularly striking effect is observed for pyridine-docked systems. These are subject to Fermi-level pinning at high molecular packing densities, causing an abrupt increase of the junction current already at small voltages. PMID:26401191

[Omentin: Role in insulin resistance, inflammation and cardiovascular protection].

Science.gov (United States)

Hernández-Díaz, Adrián; Arana-Martínez, Julio C; Carbó, Roxana; Espinosa-Cervantes, Román; Sánchez-Muñoz, Fausto

2016-01-01

The omentin is an adipokine, which role is due to the capacity of regulate metabolic (insulin sensitivity) and anti-inflammatory activities, thus conferring vascular protection during obesity and diabetes mellitus type 2. By this, it is important to know the mechanisms by which omentin confers cardiovascular protection, with the purpose of establish omentin a possible therapeutic target or molecule on this scenario. Copyright © 2015 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

Isotope separation using vibrationally excited molecules

International Nuclear Information System (INIS)

Woodroffe, J.A.; Keck, J.C.

1979-01-01

Vibrational excitation of molecules having components of a selected isotope type is used to produce a conversion from vibrational to translational excitation of the molecules by collision with the molecules of a heavy carrier gas. The resulting difference in translaton between the molecules of the selected isotope type and all other molecules of the same compound permits their separate collection. When applied to uranium enrichment, a subsonic cryogenic flow of molecules of uranium hexafluoride in combination with an argon carrier gas is directed through a cooled chamber that is illuminated by laser radiaton tuned to vibrationally excite the uranium hexafluoride molecules of a specific uranium isotope. The excited molecules collide with carrier gas molecules, causing a conversion of the excitation energy into a translation of the excited molecule, which results in a higher thermal energy or diffusivity than that of the other uranium hexafluoride molecules. The flowing molecules including the excited molecules directly enter a set of cryogenically cooled channels. The higher thermal velocity of the excited molecules increases the probability of their striking a collector surface. The molecules which strike this surface immediately condense. After a predetermined thickness of molecules is collected on the surface, the flow of uranium hexafluoride is interrupted and the chamber heated to the point of vaporization of the collected hexafluoride, permitting its removal. (LL)

Ethical problems in radiation protection

Energy Technology Data Exchange (ETDEWEB)

Shrader-Frechette, K.; Persson, Lars

2001-05-01

In this report the authors survey existing international radiation-protection recommendations and standards of the ICRP, the IAEA, and the ILO. After outlining previous work on the ethics of radiation protection, professional ethics, and the ethics of human radiation experiments, the authors review ethical thinking on seven key issues related to radiation protection and ethics. They formulate each of these seven issues in terms of alternative ethical stances: (1) equity versus efficiency, (2) health versus economics, (3) individual rights versus societal benefits, (4) due process versus necessary sacrifice, (5) uniform versus double standards, (6) stake holder consent versus management decisions, and (7) environmental stewardship versus anthropocentric standards.

Ethical problems in radiation protection

International Nuclear Information System (INIS)

Shrader-Frechette, K.; Persson, Lars

2001-05-01

In this report the authors survey existing international radiation-protection recommendations and standards of the ICRP, the IAEA, and the ILO. After outlining previous work on the ethics of radiation protection, professional ethics, and the ethics of human radiation experiments, the authors review ethical thinking on seven key issues related to radiation protection and ethics. They formulate each of these seven issues in terms of alternative ethical stances: (1) equity versus efficiency, (2) health versus economics, (3) individual rights versus societal benefits, (4) due process versus necessary sacrifice, (5) uniform versus double standards, (6) stake holder consent versus management decisions, and (7) environmental stewardship versus anthropocentric standards

A fingerprint key binding algorithm based on vector quantization and error correction

Science.gov (United States)

Li, Liang; Wang, Qian; Lv, Ke; He, Ning

2012-04-01

In recent years, researches on seamless combination cryptosystem with biometric technologies, e.g. fingerprint recognition, are conducted by many researchers. In this paper, we propose a binding algorithm of fingerprint template and cryptographic key to protect and access the key by fingerprint verification. In order to avoid the intrinsic fuzziness of variant fingerprints, vector quantization and error correction technique are introduced to transform fingerprint template and then bind with key, after a process of fingerprint registration and extracting global ridge pattern of fingerprint. The key itself is secure because only hash value is stored and it is released only when fingerprint verification succeeds. Experimental results demonstrate the effectiveness of our ideas.

Single-Molecule Spectroscopy

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 2. Single-Molecule Spectroscopy: Every Molecule is Different! Kankan Bhattacharyya. General Article Volume 20 Issue 2 February 2015 pp 151-164. Fulltext. Click here to view fulltext PDF. Permanent link:

Single molecule transcription factor dynamics in the syncytial Drosophila embryo

Science.gov (United States)

Darzacq, Xavier

During early development in the Drosophila embryo, cell fates are determined over the course of just 2 hours with exquisite spatio-temoral precision. One of the key regulators of this process is the transcription factor Bicoid which forms a concentration gradient across the long axis of the embryo. Although Bicoids' primary role is activation at the anterior, where concentrations are highest, it is also known to play a role in the posterior where there are only 100s of molecules per nucleus. Understanding how Bicoid can find its target at such low concentrations has remained intractable, largely due to the inability to perform single molecule imaging in the context of the developing embryo. Here we use lattice light sheet microscopy to overcome the technical barriers of sample thickness and auto-fluorescence to characterize the single molecule dynamics of Bicoid. We find that off-rates do not vary across the embryo and that instead the on-rates are modulated through the formation of clusters that enrich local concentration. This data is contrary to the current concentration dependent model of Bicoid function since local concentration within the nucleus is now a regulated parameter and suggests a previously unknown mechanism for regulation at extremely low concentrations.

Antioxidant capacity contributes to protection of ketone bodies against oxidative damage induced during hypoglycemic conditions.

Science.gov (United States)

Haces, María L; Hernández-Fonseca, Karla; Medina-Campos, Omar N; Montiel, Teresa; Pedraza-Chaverri, José; Massieu, Lourdes

2008-05-01

Ketone bodies play a key role in mammalian energy metabolism during the suckling period. Normally ketone bodies' blood concentration during adulthood is very low, although it can rise during starvation, an exogenous infusion or a ketogenic diet. Whenever ketone bodies' levels increase, their oxidation in the brain rises. For this reason they have been used as protective molecules against refractory epilepsy and in experimental models of ischemia and excitotoxicity. The mechanisms underlying the protective effect of these compounds are not completely understood. Here, we studied a possible antioxidant capacity of ketone bodies and whether it contributes to the protection against oxidative damage induced during hypoglycemia. We report for the first time the scavenging capacity of the ketone bodies, acetoacetate (AcAc) and both the physiological and non-physiological isomers of beta-hydroxybutyrate (D- and L-BHB, respectively), for diverse reactive oxygen species (ROS). Hydroxyl radicals (.OH) were effectively scavenged by D- and L-BHB. In addition, the three ketone bodies were able to reduce cell death and ROS production induced by the glycolysis inhibitor, iodoacetate (IOA), while only D-BHB and AcAc prevented neuronal ATP decline. Finally, in an in vivo model of insulin-induced hypoglycemia, the administration of D- or L-BHB, but not of AcAc, was able to prevent the hypoglycemia-induced increase in lipid peroxidation in the rat hippocampus. Our data suggest that the antioxidant capacity contributes to protection of ketone bodies against oxidative damage in in vitro and in vivo models associated with free radical production and energy impairment.

Monofunctional stealth nanoparticle for unbiased single molecule tracking inside living cells.

Science.gov (United States)

Lisse, Domenik; Richter, Christian P; Drees, Christoph; Birkholz, Oliver; You, Changjiang; Rampazzo, Enrico; Piehler, Jacob

2014-01-01

On the basis of a protein cage scaffold, we have systematically explored intracellular application of nanoparticles for single molecule studies and discovered that recognition by the autophagy machinery plays a key role for rapid metabolism in the cytosol. Intracellular stealth nanoparticles were achieved by heavy surface PEGylation. By combination with a generic approach for nanoparticle monofunctionalization, efficient labeling of intracellular proteins with high fidelity was accomplished, allowing unbiased long-term tracking of proteins in the outer mitochondrial membrane.

Geoheritage protection of Serbia: Present situation and perspectives

Directory of Open Access Journals (Sweden)

Jojić-Glavonjić Tamara

2010-01-01

Full Text Available Neglected for decades in relation to the biodiversity and cultural heritage protection, the geoheritage protection has become a new concept, having more and more supporters in the world. The middle of the 1990s marked the beginning of the systematic geoheritage protection in Serbia. The basic components of that process are represented in the paper with the aim of evaluating the situation and noticing the key problems.

Child Protection Decision Making: A Factorial Analysis Using Case Vignettes

Science.gov (United States)

Stokes, Jacqueline; Schmidt, Glen

2012-01-01

This study explored decision making by child protection social workers in the province of British Columbia, Canada. A factorial survey method was used in which case vignettes were constructed by randomly assigning a number of key characteristics associated with decision making in child protection. Child protection social workers (n = 118) assessed…

Melatonin: A Mitochondrial Targeting Molecule Involving Mitochondrial Protection and Dynamics

Science.gov (United States)

Tan, Dun-Xian; Manchester, Lucien C.; Qin, Lilan; Reiter, Russel J.

2016-01-01

Melatonin has been speculated to be mainly synthesized by mitochondria. This speculation is supported by the recent discovery that aralkylamine N-acetyltransferase/serotonin N-acetyltransferase (AANAT/SNAT) is localized in mitochondria of oocytes and the isolated mitochondria generate melatonin. We have also speculated that melatonin is a mitochondria-targeted antioxidant. It accumulates in mitochondria with high concentration against a concentration gradient. This is probably achieved by an active transportation via mitochondrial melatonin transporter(s). Melatonin protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting the mitochondrial permeability transition pore (MPTP), and activating uncoupling proteins (UCPs). Thus, melatonin maintains the optimal mitochondrial membrane potential and preserves mitochondrial functions. In addition, mitochondrial biogenesis and dynamics is also regulated by melatonin. In most cases, melatonin reduces mitochondrial fission and elevates their fusion. Mitochondrial dynamics exhibit an oscillatory pattern which matches the melatonin circadian secretory rhythm in pinealeocytes and probably in other cells. Recently, melatonin has been found to promote mitophagy and improve homeostasis of mitochondria. PMID:27999288

High expression of carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 6 and 8 in primary myelofibrosis

DEFF Research Database (Denmark)

Riley, Caroline Hasselbalch; Skov, Vibe; Larsen, Thomas Stauffer

2011-01-01

for the egress of CD34+ cells from the bone marrow. Carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 6 has been implicated in cell adhesion, cellular invasiveness, angiogenesis, and inflammation, which are all key processes in the pathophysiology of PMF. Accordingly, CEACAMs may play an important...

Ion-Molecule Reaction Dynamics.

Science.gov (United States)

Meyer, Jennifer; Wester, Roland

2017-05-05

We review the recent advances in the investigation of the dynamics of ion-molecule reactions. During the past decade, the combination of single-collision experiments in crossed ion and neutral beams with the velocity map ion imaging detection technique has enabled a wealth of studies on ion-molecule reactions. These methods, in combination with chemical dynamics simulations, have uncovered new and unexpected reaction mechanisms, such as the roundabout mechanism and the subtle influence of the leaving group in anion-molecule nucleophilic substitution reactions. For this important class of reactions, as well as for many fundamental cation-molecule reactions, the information obtained with crossed-beam imaging is discussed. The first steps toward understanding micro-solvation of ion-molecule reaction dynamics are presented. We conclude with the presentation of several interesting directions for future research.

The influence of increased cross-linker chain length in thermosensitive microspheres on potential sun-protection activity

OpenAIRE

Musiał, Witold; Kokol, Vanja; Vončina, Bojana

2012-01-01

The sun protection should involve substances with protecting activity against both UVB and UVA radiation. In this research the evaluation of thermosensitive microspheres as potential molecules for sunscreen formulations was approached, using modified Boots star rating system. The microspheres, thermosensitive N-isopropylacrylamide derivatives, have potential protecting activity against UV radiation. The MX and DX microspheres, with ethylene glycol dimethacrylate and diethylene glycol dimethac...

Manipulating the dipole layer of polar organic molecules on metal surfaces via different charge-transfer channels

Science.gov (United States)

Lin, Meng-Kai; Nakayama, Yasuo; Zhuang, Ying-Jie; Wang, Chin-Yung; Pi, Tun-Wen; Ishii, Hisao; Tang, S.-J.

The key properties of organic films such as energy level alignment (ELA), work functions, and injection barriers are closely linked to this dipole layer. Using angle resolved photoemission spectroscopy (ARPES), we systemically investigate the coverage-dependent work functions and spectra line shapes of occupied molecular orbital states of a polar molecule, chloroaluminium phthalocyanine (ClAlPc), grown on Ag(111) to show that the orientations of the first ClAlPc layer can be manipulated via the molecule deposition rate and post annealing, causing ELA at organic-metal interface to differ for about 0.3 eV between Cl-up and Cl-down configuration. Moreover, by comparing the experimental results with the calculations based on both gas-phase model and realistic model of ClAlPc on Ag(111) , we evidence that the different orientations of ClAlPc dipole layers lead to different charge-transfer channels between ClAlPc and Ag, a key factor that controls the ELA at organic-metal interface.

Electron Accumulative Molecules.

Science.gov (United States)

Buades, Ana B; Sanchez Arderiu, Víctor; Olid-Britos, David; Viñas, Clara; Sillanpää, Reijo; Haukka, Matti; Fontrodona, Xavier; Paradinas, Markos; Ocal, Carmen; Teixidor, Francesc

2018-02-28

With the goal to produce molecules with high electron accepting capacity and low reorganization energy upon gaining one or more electrons, a synthesis procedure leading to the formation of a B-N(aromatic) bond in a cluster has been developed. The research was focused on the development of a molecular structure able to accept and release a specific number of electrons without decomposing or change in its structural arrangement. The synthetic procedure consists of a parallel decomposition reaction to generate a reactive electrophile and a synthesis reaction to generate the B-N(aromatic) bond. This procedure has paved the way to produce the metallacarboranylviologen [M(C 2 B 9 H 11 )(C 2 B 9 H 10 )-NC 5 H 4 -C 5 H 4 N-M'(C 2 B 9 H 11 )(C 2 B 9 H 10 )] (M = M' = Co, Fe and M = Co and M' = Fe) and semi(metallacarboranyl)viologen [3,3'-M(8-(NC 5 H 4 -C 5 H 4 N-1,2-C 2 B 9 H 10 )(1',2'-C 2 B 9 H 11 )] (M = Co, Fe) electron cumulative molecules. These molecules are able to accept up to five electrons and to donate one in single electron steps at accessible potentials and in a reversible way. By targeted synthesis and corresponding electrochemical tests each electron transfer (ET) step has been assigned to specific fragments of the molecules. The molecules have been carefully characterized, and the electronic communication between both metal centers (when this situation applies) has been definitely observed through the coplanarity of both pyridine fragments. The structural characteristics of these molecules imply a low reorganization energy that is a necessary requirement for low energy ET processes. This makes them electronically comparable to fullerenes, but on their side, they have a wide range of possible solvents. The ET from one molecule to another has been clearly demonstrated as well as their self-organizing capacity. We consider that these molecules, thanks to their easy synthesis, ET, self-organizing capacity, wide range of solubility, and easy processability, can

Single molecule conductance

NARCIS (Netherlands)

Willems, R.

2008-01-01

This thesis represents an excursion into the world of molecular electronics, i.e. the field of research trying to use individual (organic) molecules as electronic components; in this work various experimental methods have been explored to connect individual molecules to metallic contacts and

Modulation of dendritic cell and T cell cross-talk during aging: The potential role of checkpoint inhibitory molecules.

Science.gov (United States)

Gardner, Joanne K; Mamotte, Cyril D S; Jackaman, Connie; Nelson, Delia J

2017-09-01

Dendritic cells (DCs) undergo continuous changes throughout life, and there is evidence that elderly DCs have a reduced capacity to stimulate T cells, which may contribute to impaired anti-tumour immune responses in elderly people with cancer. Changes in checkpoint inhibitory molecules/pathways during aging may be one mechanism that impairs the ability of elderly DCs to activate T cells. However, little is currently known regarding the combined effects of aging and cancer on DC and T cell inhibitory molecules/pathways. In this review, we discuss our current understanding of the influence of aging and cancer on key DC and T cell inhibitory molecules/pathways, the potential underlying cellular and molecular mechanisms contributing to their modulation, and the possibility of therapeutically targeting inhibitory molecules in elderly cancer patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Under Lock and Key: Preventing Campus Theft of Electronic Equipment.

Science.gov (United States)

Harrison, J. Phil

1996-01-01

A discussion of computer theft prevention on college campuses looks at a variety of elements in electronic equipment security, including the extent of the problem, physical antitheft products, computerized access, control of key access, alarm systems, competent security personnel, lighting, use of layers of protection, and increasing…

76 FR 48807 - Public Key Infrastructure (PKI) Certificate Action Form

Science.gov (United States)

2011-08-09

... Infrastructure (PKI) technology to support electronic commerce between the USPTO and its customers. PKI is a set... security for its electronic commerce systems, the USPTO uses PKI technology to protect the integrity and... DEPARTMENT OF COMMERCE United States Patent and Trademark Office Public Key Infrastructure (PKI...

Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation

Science.gov (United States)

Wang, C.-W.; Stark, W.

2005-01-01

This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.

The Molecule Cloud - compact visualization of large collections of molecules

Directory of Open Access Journals (Sweden)

Ertl Peter

2012-07-01

Full Text Available Abstract Background Analysis and visualization of large collections of molecules is one of the most frequent challenges cheminformatics experts in pharmaceutical industry are facing. Various sophisticated methods are available to perform this task, including clustering, dimensionality reduction or scaffold frequency analysis. In any case, however, viewing and analyzing large tables with molecular structures is necessary. We present a new visualization technique, providing basic information about the composition of molecular data sets at a single glance. Summary A method is presented here allowing visual representation of the most common structural features of chemical databases in a form of a cloud diagram. The frequency of molecules containing particular substructure is indicated by the size of respective structural image. The method is useful to quickly perceive the most prominent structural features present in the data set. This approach was inspired by popular word cloud diagrams that are used to visualize textual information in a compact form. Therefore we call this approach “Molecule Cloud”. The method also supports visualization of additional information, for example biological activity of molecules containing this scaffold or the protein target class typical for particular scaffolds, by color coding. Detailed description of the algorithm is provided, allowing easy implementation of the method by any cheminformatics toolkit. The layout algorithm is available as open source Java code. Conclusions Visualization of large molecular data sets using the Molecule Cloud approach allows scientists to get information about the composition of molecular databases and their most frequent structural features easily. The method may be used in the areas where analysis of large molecular collections is needed, for example processing of high throughput screening results, virtual screening or compound purchasing. Several example visualizations of large

Managing for ecological integrity in protected wildlands: Key management challenges and research priorities in British Columbia

Science.gov (United States)

Pamela A. Wright

2007-01-01

Protected areas have long served two masters: providing recreation, tourism and economic opportunities while conserving resources. As wild lands have become more scarce, there has been increasing realization that recreational use of protected areas is not benign. Consequently, there has been growing discussion and debate about how to reconcile human use with...

A comprehensive study of extended tetrathiafulvalene cruciform molecules for molecular electronics: synthesis and electrical transport measurements.

Science.gov (United States)

Parker, Christian R; Leary, Edmund; Frisenda, Riccardo; Wei, Zhongming; Jennum, Karsten S; Glibstrup, Emil; Abrahamsen, Peter Bæch; Santella, Marco; Christensen, Mikkel A; Della Pia, Eduardo Antonio; Li, Tao; Gonzalez, Maria Teresa; Jiang, Xingbin; Morsing, Thorbjørn J; Rubio-Bollinger, Gabino; Laursen, Bo W; Nørgaard, Kasper; van der Zant, Herre; Agrait, Nicolas; Nielsen, Mogens Brøndsted

2014-11-26

Cruciform-like molecules with two orthogonally placed π-conjugated systems have in recent years attracted significant interest for their potential use as molecular wires in molecular electronics. Here we present synthetic protocols for a large selection of cruciform molecules based on oligo(phenyleneethynylene) (OPE) and tetrathiafulvalene (TTF) scaffolds, end-capped with acetyl-protected thiolates as electrode anchoring groups. The molecules were subjected to a comprehensive study of their conducting properties as well as their photophysical and electrochemical properties in solution. The complex nature of the molecules and their possible binding in different configurations in junctions called for different techniques of conductance measurements: (1) conducting-probe atomic force microscopy (CP-AFM) measurements on self-assembled monolayers (SAMs), (2) mechanically controlled break-junction (MCBJ) measurements, and (3) scanning tunneling microscopy break-junction (STM-BJ) measurements. The CP-AFM measurements showed structure-property relationships from SAMs of series of OPE3 and OPE5 cruciform molecules; the conductance of the SAM increased with the number of dithiafulvene (DTF) units (0, 1, 2) along the wire, and it increased when substituting two arylethynyl end groups of the OPE3 backbone with two DTF units. The MCBJ and STM-BJ studies on single molecules both showed that DTFs decreased the junction formation probability, but, in contrast, no significant influence on the single-molecule conductance was observed. We suggest that the origins of the difference between SAM and single-molecule measurements lie in the nature of the molecule-electrode interface as well as in effects arising from molecular packing in the SAMs. This comprehensive study shows that for complex molecules care should be taken when directly comparing single-molecule measurements and measurements of SAMs and solid-state devices thereof.

Radiation protection experience in Yugoslavia from the Vinca accident to nowadays

International Nuclear Information System (INIS)

Ninkovic, M.M

2000-01-01

This Paper is the expression of the author opinion about development of radiation protection in Yugoslavia from its beginning forty years ago, which might affect its status in the foreseeable future at the first decades of the 21st century. It focuses on key events in this field starting from the Vinca Accident, which happened in the October 1958, to nowadays. Shortly reviewed some of key events are: Vinca Accident; Foundation of the Radiation Protection Laboratory in the Vinca Institute; International Vinca Dosimetry Experiment; First National Symposium and foundation of the Yugoslav Radiation Protection Association; International Intercomparison Experiment on Nuclear Accident Dosimetry and, International Summer Schools and Symposium on Radiation Protection organized in Yugoslavia. Finally, some specific experimental data obtained during and after Chernobyl Accident up to nowadays in radiation protection action in Yugoslavia are presented also. (author)

Analysing PKCS#11 Key Management APIs with Unbounded Fresh Data

Science.gov (United States)

Fröschle, Sibylle; Steel, Graham

We extend Delaune, Kremer and Steel’s framework for analysis of PKCS#11-based APIs from bounded to unbounded fresh data. We achieve this by: formally defining the notion of an attribute policy; showing that a well-designed API should have a certain class of policy we call complete; showing that APIs with complete policies may be safely abstracted to APIs where the attributes are fixed; and proving that these static APIs can be analysed in a small bounded model such that security properties will hold for the unbounded case. We automate analysis in our framework using the SAT-based security protocol model checker SATMC. We show that a symmetric key management subset of the Eracom PKCS#11 API, used in their ProtectServer product, preserves the secrecy of sensitive keys for unbounded numbers of fresh keys and handles, i.e. pointers to keys. We also show that this API is not robust: if an encryption key is lost to the intruder, SATMC finds an attack whereby all the keys may be compromised.

Underlying Motives, Moral Agendas and Unlikely Partnerships: The Formulation of the U.S. Trafficking in Victims Protection Act Through the Data and Voices of Key Policy Players

Directory of Open Access Journals (Sweden)

Nicole Footen Bromfield

2012-08-01

Full Text Available In response to the overwhelming amount of attention to human trafficking, the debates surrounding its definition, and its focus on the sex industry, the purpose of this study was to understand the motivations behind the formation of the Trafficking in Victims Protection Act (TVPA. Using the Advocacy Coalition Framework (ACF as a model, data was collected and analyzed in order to examine the coalition identities of key players and their positions. Through the presentation of in-depth interview data with key policy players involved in the making of the TVPA, this article illustrates how and why the TVPA was formulated, the implications of its development, and the necessity for critical analysis of its effects. The use of alternative frameworks of labor and migration for understanding trafficking is proposed. Further consideration is given to legislative changes to eliminate anti-prostitution ideology and to support anti-oppressive approaches to addressing forced or deceptive working conditions.

Challenges for single molecule electronic devices with nanographene and organic molecules. Do single molecules offer potential as elements of electronic devices in the next generation?

Science.gov (United States)

Enoki, Toshiaki; Kiguchi, Manabu

2018-03-01

Interest in utilizing organic molecules to fabricate electronic materials has existed ever since organic (molecular) semiconductors were first discovered in the 1950s. Since then, scientists have devoted serious effort to the creation of various molecule-based electronic systems, such as molecular metals and molecular superconductors. Single-molecule electronics and the associated basic science have emerged over the past two decades and provided hope for the development of highly integrated molecule-based electronic devices in the future (after the Si-based technology era has ended). Here, nanographenes (nano-sized graphene) with atomically precise structures are among the most promising molecules that can be utilized for electronic/spintronic devices. To manipulate single small molecules for an electronic device, a single molecular junction has been developed. It is a powerful tool that allows even small molecules to be utilized. External electric, magnetic, chemical, and mechanical perturbations can change the physical and chemical properties of molecules in a way that is different from bulk materials. Therefore, the various functionalities of molecules, along with changes induced by external perturbations, allows us to create electronic devices that we cannot create using current top-down Si-based technology. Future challenges that involve the incorporation of condensed matter physics, quantum chemistry calculations, organic synthetic chemistry, and electronic device engineering are expected to open a new era in single-molecule device electronic technology.

Mini-chamber, an advanced protection concept for NIF

International Nuclear Information System (INIS)

Peterson, P.F.; Scott, J.M.

1996-01-01

Inertial confinement fusion (ICF) target debris and ablated near-target materials pose the primary threat to the National Ignition Facility (NIF) final optics debris shields, as well as a major challenge in future inertial fusion energy (IFE) power plants. This work discusses a NIF 'mini-chamber,' designed to mitigate the debris threat. Although the NIF base-line design protects against debris using a frost-protected target positioner and refractory first-wall coatings, the mini-chamber provides important flexibility in three areas: debris-shield protection from beyond-design basis shots (i.e. heavy hohlraums, special diagnostics, shields); fielding of large experiments with significant surface ablation; and studying key ablation and gas-dynamics issues for liquid-wall IFE power plants. Key mini-chamber modeling results are presented, followed by discussion of equipment requirements for fielding a NIF mini-chamber. 7 refs., 3 figs

Understanding the cognitive basis for human-wildlife relationships as a key to successful protected-area management

DEFF Research Database (Denmark)

Teel, Tara L.; Manfredo, Michael J.; Jensen, Frank Søndergaard

2010-01-01

Wildlife is a critical component of protected areas worldwide. It can serve not only as a primary attraction or an enjoyable part of the visitor experience but also as source of conflict. Managing wildlife in this context requires a broadbased approach that can account for the myriad factors...... this micro-macro approach and explore its implications for protected-area management. First, data from nineteen-state study conducted in 2004 via mail survey in the united States show how two contrasting orientations - dominations and mutualism - produce different attitudes and behaviors toward wildlife...... to wildlife issues. Together, these studies highlight the importance of multilevel models for exploring the social aspects of wildlife and protected-area management....

Social Isolation, Psychological Health, and Protective Factors in Adolescence

Science.gov (United States)

Hall-Lande, Jennifer A.; Eisenberg, Marla E.; Christenson, Sandra L.; Neumark-Sztainer, Dianne

2007-01-01

This study investigates the relationships among social isolation, psychological health, and protective factors in adolescents. Feelings of social isolation may influence psychological health in adolescents, but protective factors such as family connectedness, school connectedness, and academic achievement may also play a key role. The sample…

Electron-molecule collisions

CERN Document Server

Takayanagi, Kazuo

1984-01-01

Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

Preparation of translationally cold neutral molecules.

Science.gov (United States)

Di Domenicantonio, Giulia; Bertsche, Benjamin; Osterwalder, Andreas

2011-01-01

Efforts at EPFL to obtain translationally cold neutral molecules are described. Active deceleration of polar molecules is performed by confining the molecules in moving three-dimensional electrostatic traps, and by appropriately choosing the velocity of those traps. Alternatively, cold molecules can be obtained by velocity filtering. Here, the velocity of the molecules is not changed, but instead the cold molecules are extracted from a thermal sample by using the competition between the electrostatic force and the centrifugal force inside a bent electrostatic guide for polar molecules.

Trade secrets protection mode of nuclear power plant

International Nuclear Information System (INIS)

Zeng Bin

2015-01-01

The paper analyzes the legal environment in which nuclear power enterprises are stayed, and mainly discusses the business secret protection modes of China's nuclear power enterprises. It is expected to provide a revelation and help for these enterprises to protect their business secrets. Firstly, the paper briefly expounds the legal basis of business secret protection and China's legalization status in this regard. Then it mainly puts forward the business secret management framework and postulations for nuclear power enterprises, and key points in application and protection of nuclear power business secret. (author)

Resonant electron capture by aspartame and aspartic acid molecules.

Science.gov (United States)

Muftakhov, M V; Shchukin, P V

2016-12-30

The processes for dissociative electron capture are the key mechanisms for decomposition of biomolecules, proteins in particular, under interaction with low-energy electrons. Molecules of aspartic acid and aspartame, i.e. modified dipeptides, were studied herein to define the impact of the side functional groups on peptide chain decomposition in resonant electron-molecular reactions. The processes of formation and decomposition of negative ions of both aspartame and aspartic acid were studied by mass spectrometry of negative ions under resonant electron capture. The obtained mass spectra were interpreted under thermochemical analysis by quantum chemical calculations. Main channels of negative molecular ions fragmentation were found and characteristic fragment ions were identified. The СООН fragment of the side chain in aspartic acid is shown to play a key role like the carboxyl group in amino acids and aliphatic oligopeptides. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Single-Molecule Electronics with Cross- Conjugated Molecules: Quantum Interference, IETS and Non-Equilibrium "Temperatures"

DEFF Research Database (Denmark)

Jørgensen, Jacob Lykkebo

Abstract The idea of using single-molecules as components in electronic devices is fas- cinating. For this idea to come into fruition, a number of technical and theo- retical challenges must be overcome. In this PhD thesis, the electron-phonon interaction is studied for a special class of molecules......, which is characterised by destructive quantum interference. The molecules are cross-conjugated, which means that the two parts of the molecules are conjugated to a third part, but not to each other. This gives rise to an anti-resonance in the trans- mission. In the low bias and low temperature regime......-conjugated molecules. We nd that the vibrational modes that would be expected to dominate, following the propensity, rules are very weak. Instead, other modes are found to be the dominant ones. We study this phenomenon for a number of cross-conjugated molecules, and link these ndings to the anti...

Single Molecule Electronics and Devices

Science.gov (United States)

Tsutsui, Makusu; Taniguchi, Masateru

2012-01-01

The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led to significant progress in understanding electron transport in molecular systems at the single-molecule level and the concomitant emergence of new device concepts. Here, we review recent developments in this field. We summarize the methods currently used to form metal-molecule-metal structures and some single-molecule techniques essential for characterizing molecular junctions such as inelastic electron tunnelling spectroscopy. We then highlight several important achievements, including demonstration of single-molecule diodes, transistors, and switches that make use of electrical, photo, and mechanical stimulation to control the electron transport. We also discuss intriguing issues to be addressed further in the future such as heat and thermoelectric transport in an individual molecule. PMID:22969345

Role of chrysin on expression of insulin signaling molecules

Directory of Open Access Journals (Sweden)

Kottireddy Satyanarayana

2015-01-01

Full Text Available Background: Currently available drugs are unsuccessful for the treatment of tye-2 diabetes due to their adverseside-effects. Hence, a search for novel drugs, especially ofplant origin, continues. Chrysin (5,7-dihydroxyflavone is a flavonoid, natural component of traditional medicinal herbs, present in honey, propolis and many plant extracts that hasbeen used in traditional medicine around the world to treat numerous ailments. Objective: The present study was aimed to identify the protective role of chrysin on the expression of insulin-signaling molecules in the skeletal muscle of high fat and sucrose-induced type-2 diabetic adult male rats. Materials and Methods: The oral effective dose of chrysin (100 mg/kg body weight was given once a day until the end of the study (30 days post-induction of diabetes to high fat diet-induced diabetic rats.At the end of the experimental period, fasting blood glucose, oral glucose tolerance, serum lipid profile, lipid peroxidation (LPO and free radical generation, as well as the levels of insulin signaling molecules and tissue glycogen in the gastrocnemius muscle were assessed. Results: Diabetic rats showed impaired glucose tolerance and impairment in insulin signaling molecules (IR, IRS-1, p-IRS-1Tyr 632 , p- Akt Thr308 , glucose transporter subtype 4 [GLUT4] proteins and glycogen concentration. Serum insulin, lipid profile, LPO and free radical generation were found to be increased in diabetic control rats.The treatment with chrysin normalized the altered levels of blood glucose, serum insulin, lipid profile, LPO and insulin signaling molecules as well as GLUT4 proteins. Conclusion: Our present findings indicate that chrysin improves glycemic control through activation of insulin signal transduction in the gastrocnemius muscle of high fat and sucrose-induced type-2 diabetic male rats.

Protective relaying theory and applications

CERN Document Server

Elmore, Walter A

2003-01-01

Targeting the latest microprocessor technologies for more sophisticated applications in the field of power system short circuit detection, this revised and updated source imparts fundamental concepts and breakthrough science for the isolation of faulty equipment and minimization of damage in power system apparatus. The Second Edition clearly describes key procedures, devices, and elements crucial to the protection and control of power system function and stability. It includes chapters and expertise from the most knowledgeable experts in the field of protective relaying, and describes micropro

Improved methods for predicting peptide binding affinity to MHC class II molecules

DEFF Research Database (Denmark)

Jensen, Kamilla Kjærgaard; Andreatta, Massimo; Marcatili, Paolo

2018-01-01

Major histocompatibility complex class II (MHC-II) molecules are expressed on the surface of professional antigen presenting cells where they display peptides to T helper cells, which orchestrate the onset and outcome of many host immune responses. Understanding which peptides will be presented b...... are publicly available at www.cbs.dtu.dk/services/NetMHCII-2.3 and www.cbs.dtu.dk/services/NetMHCIIpan-3.2. This article is protected by copyright. All rights reserved....

A density-dependent switch drives stochastic clustering and polarization of signaling molecules.

Directory of Open Access Journals (Sweden)

Alexandra Jilkine

2011-11-01

Full Text Available Positive feedback plays a key role in the ability of signaling molecules to form highly localized clusters in the membrane or cytosol of cells. Such clustering can occur in the absence of localizing mechanisms such as pre-existing spatial cues, diffusional barriers, or molecular cross-linking. What prevents positive feedback from amplifying inevitable biological noise when an un-clustered "off" state is desired? And, what limits the spread of clusters when an "on" state is desired? Here, we show that a minimal positive feedback circuit provides the general principle for both suppressing and amplifying noise: below a critical density of signaling molecules, clustering switches off; above this threshold, highly localized clusters are recurrently generated. Clustering occurs only in the stochastic regime, suggesting that finite sizes of molecular populations cannot be ignored in signal transduction networks. The emergence of a dominant cluster for finite numbers of molecules is partly a phenomenon of random sampling, analogous to the fixation or loss of neutral mutations in finite populations. We refer to our model as the "neutral drift polarity model." Regulating the density of signaling molecules provides a simple mechanism for a positive feedback circuit to robustly switch between clustered and un-clustered states. The intrinsic ability of positive feedback both to create and suppress clustering is a general mechanism that could operate within diverse biological networks to create dynamic spatial organization.

Involvement of HLA class I molecules in the immune escape of urologic tumors.

Science.gov (United States)

Carretero, R; Gil-Julio, H; Vázquez-Alonso, F; Garrido, F; Castiñeiras, J; Cózar, J M

2014-04-01

To analyze the influence of different alterations in human leukocyte antigen class I molecules (HLA I) in renal cell carcinoma, as well as in bladder and prostate cancer. We also study the correlation between HLA I expression and the progression of the disease and the response after immunotherapy protocols. It has been shown, experimentally, that the immune system can recognize and kill neoplastic cells. By analyzing the expression of HLA I molecules on the surface of cancer cells, we were able to study the tumor escape mechanisms against the immune system. Alteration or irreversible damage in HLA I molecules is used by the neoplastic cells to escape the immune system. The function of these molecules is to recognize endogenous peptides and present them to T cells of the immune system. There is a clear relationship between HLA I reversible alterations and success of therapy. Irreversible lesions also imply a lack of response to treatment. The immune system activation can reverse HLA I molecules expression in tumors with reversible lesions, whereas tumors with irreversible ones do not respond to such activation. Determine the type of altered HLA I molecules in tumors is of paramount importance when choosing the type of treatment to keep looking for therapeutic success. Those tumors with reversible lesions can be treated with traditional immunotherapy; however, tumour with irreversible alterations should follow alternative protocols, such as the use of viral vectors carrying the HLA genes to achieve damaged re-expression of the protein. From studies in urologic tumors, we can conclude that the HLA I molecules play a key role in these tumors escape to the immune system. Copyright © 2013 AEU. Published by Elsevier Espana. All rights reserved.

EDITORIAL: Focus on Cold and Ultracold Molecules FOCUS ON COLD AND ULTRACOLD MOLECULES

Science.gov (United States)

Carr, Lincoln D.; Ye, Jun

2009-05-01

Cold and ultracold molecules are the next wave of ultracold physics, giving rise to an exciting array of scientific opportunities, including many body physics for novel quantum phase transitions, new states of matter, and quantum information processing. Precision tests of fundamental physical laws benefit from the existence of molecular internal structure with exquisite control. The study of novel collision and reaction dynamics will open a new chapter of quantum chemistry. Cold molecules bring together researchers from a variety of fields, including atomic, molecular, and optical physics, chemistry and chemical physics, quantum information science and quantum simulations, condensed matter physics, nuclear physics, and astrophysics, a truly remarkable synergy of scientific explorations. For the past decade there have been steady advances in direct cooling techniques, from buffer-gas cooling to cold molecular beams to electro- and magneto-molecular decelerators. These techniques have allowed a large variety of molecules to be cooled for pioneering studies. Recent amazing advances in experimental techniques combining the ultracold and the ultraprecise have furthermore brought molecules to the point of quantum degeneracy. These latter indirect cooling techniques magnetically associate atoms from a Bose-Einstein condensate and/or a quantum degenerate Fermi gas, transferring at 90% efficiency highly excited Fano-Feshbach molecules, which are on the order of 10 000 Bohr radii in size, to absolute ground state molecules just a few Bohr across. It was this latter advance, together with significant breakthroughs in internal state manipulations, which inspired us to coordinate this focus issue now, and is the reason why we say the next wave of ultracold physics has now arrived. Whether directly or indirectly cooled, heteronuclear polar molecules offer distinct new features in comparison to cold atoms, while sharing all of their advantages (purity, high coherence

Reverse engineering of an affinity-switchable molecular interaction characterized by atomic force microscopy single-molecule force spectroscopy.

Science.gov (United States)

Anselmetti, Dario; Bartels, Frank Wilco; Becker, Anke; Decker, Björn; Eckel, Rainer; McIntosh, Matthew; Mattay, Jochen; Plattner, Patrik; Ros, Robert; Schäfer, Christian; Sewald, Norbert

2008-02-19

Tunable and switchable interaction between molecules is a key for regulation and control of cellular processes. The translation of the underlying physicochemical principles to synthetic and switchable functional entities and molecules that can mimic the corresponding molecular functions is called reverse molecular engineering. We quantitatively investigated autoinducer-regulated DNA-protein interaction in bacterial gene regulation processes with single atomic force microscopy (AFM) molecule force spectroscopy in vitro, and developed an artificial bistable molecular host-guest system that can be controlled and regulated by external signals (UV light exposure and thermal energy). The intermolecular binding functionality (affinity) and its reproducible and reversible switching has been proven by AFM force spectroscopy at the single-molecule level. This affinity-tunable optomechanical switch will allow novel applications with respect to molecular manipulation, nanoscale rewritable molecular memories, and/or artificial ion channels, which will serve for the controlled transport and release of ions and neutral compounds in the future.

40 CFR 355.3 - Which section contains the definitions of the key words used in this part?

Science.gov (United States)

2010-07-01

... of the key words used in this part? 355.3 Section 355.3 Protection of Environment ENVIRONMENTAL... words used in this part? The definitions of key words used in this part are in § 355.61. It is important to read the definitions for these key words because the definition explains the word's specific...

Single-Molecule Photocurrent at a Metal-Molecule-Semiconductor Junction.

Science.gov (United States)

Vezzoli, Andrea; Brooke, Richard J; Higgins, Simon J; Schwarzacher, Walther; Nichols, Richard J

2017-11-08

We demonstrate here a new concept for a metal-molecule-semiconductor nanodevice employing Au and GaAs contacts that acts as a photodiode. Current-voltage traces for such junctions are recorded using a STM, and the "blinking" or "I(t)" method is used to record electrical behavior at the single-molecule level in the dark and under illumination, with both low and highly doped GaAs samples and with two different types of molecular bridge: nonconjugated pentanedithiol and the more conjugated 1,4-phenylene(dimethanethiol). Junctions with highly doped GaAs show poor rectification in the dark and a low photocurrent, while junctions with low doped GaAs show particularly high rectification ratios in the dark (>10 3 for a 1.5 V bias potential) and a high photocurrent in reverse bias. In low doped GaAs, the greater thickness of the depletion layer not only reduces the reverse bias leakage current, but also increases the volume that contributes to the photocurrent, an effect amplified by the point contact geometry of the junction. Furthermore, since photogenerated holes tunnel to the metal electrode assisted by the HOMO of the molecular bridge, the choice of the latter has a strong influence on both the steady state and transient metal-molecule-semiconductor photodiode response. The control of junction current via photogenerated charge carriers adds new functionality to single-molecule nanodevices.

Complex Molecules in the Laboratory - a Comparison of Chriped Pulse and Emission Spectroscopy

Science.gov (United States)

Hermanns, Marius; Wehres, Nadine; Maßen, Jakob; Schlemmer, Stephan

2017-06-01

Detecting molecules of astrophysical interest in the interstellar medium strongly relies on precise spectroscopic data from the laboratory. In recent years, the advancement of the chirped-pulse technique has added many more options available to choose from. The Cologne emission spectrometer is an additional path to molecular spectroscopy. It allows to record instantaneously broad band spectra with calibrated intensities. Here we present a comparison of both methods: The Cologne chirped-pulse spectrometer as well as the Cologne emission spectrometer both cover the frequency range of 75-110 GHz, consistent with the ALMA Band 3 receivers. High sensitive heterodyne receivers with very low noise temperature amplifiers are used with a typical bandwidth of 2.5 GHz in a single sideband. Additionally the chirped-pulse spectrometer contains a high power amplifier of 200 mW for the excitation of molecules. Room temperature spectra of methyl cyanide and comparison of key features, such as measurement time, sensitivity, limitations and commonalities are shown in respect to identification of complex molecules of astrophysical importance. In addition, future developments for both setups will be discussed.

Adhesion molecules

CERN Document Server

Preedy, Victor R

2016-01-01

This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

Environmentally friendly hybrid coatings for corrosion protection: silane based pre-treatments and nanostructured waterborne coatings

OpenAIRE

Fedel, Michele

2009-01-01

This thesis considers a nanotechnology approach based on the production of metals pre-treatments and organic coatings (a complete protection system at all) designed from the nanoscale. The final aim is to develop protection systems with improved corrosion protection properties and a low environmental impact. In particular, multifunctional silane hybrid molecules were used to design sol-gel pre-treatments for metals and to modify the inner structure of UV curable waterborne organic coatings...

Chemically resistant, biocompatible and microstructured surface protection

International Nuclear Information System (INIS)

Hoffmann, W.; Pham, M.T.; Hueller, J.

1984-01-01

Subject of the invention are chemicallly resistant, biocompatible, and microstructured surface protective coatings of electronic elements and sensors including chemical sensors. Such coatings consist of a radiation-modified organic substance made of a microlithographic material. Modification can be achieved by irradiation with ions, atoms or molecules having an energy between 1 KeV and 1 MeV and a flux between 10 13 and 10 18 particles per cm 2

Stability of matter-antimatter molecules

International Nuclear Information System (INIS)

Wong, Cheuk-Yin; Lee, Teck-Ghee

2011-01-01

Highlights: → We examine stability of matter-antimatter molecules with four constituents. → The binding of matter-antimatter molecules is a common phenomenon. → Molecules have bound states if ratio of constituent masses greater than ∼4. → We evaluate molecular binding energies and annihilation lifetimes. - Abstract: We examine the stability of matter-antimatter molecules by reducing the four-body problem into a simpler two-body problem with residual interactions. We find that matter-antimatter molecules with constituents (m 1 + ,m 2 - ,m-bar 2 + ,m-bar 1 - ) possess bound states if their constituent mass ratio m 1 /m 2 is greater than about 4. This stability condition suggests that the binding of matter-antimatter molecules is a rather common phenomenon. We evaluate the binding energies and eigenstates of matter-antimatter molecules (μ + e - )-(e + μ - ),(π + e - )-(e + π - ),(K + e - )-(e + K - ),(pe - )-(e + p-bar),(pμ - )-(μ + p-bar), and (K + μ - ) - (μ + K - ), which satisfy the stability condition. We estimate the molecular annihilation lifetimes in their s states.

Transport mirages in single-molecule devices

Science.gov (United States)

Gaudenzi, R.; Misiorny, M.; Burzurí, E.; Wegewijs, M. R.; van der Zant, H. S. J.

2017-03-01

Molecular systems can exhibit a complex, chemically tailorable inner structure which allows for targeting of specific mechanical, electronic, and optical properties. At the single-molecule level, two major complementary ways to explore these properties are molecular quantum-dot structures and scanning probes. This article outlines comprehensive principles of electron-transport spectroscopy relevant to both these approaches and presents a new, high-resolution experiment on a high-spin single-molecule junction exemplifying these principles. Such spectroscopy plays a key role in further advancing our understanding of molecular and atomic systems, in particular, the relaxation of their spin. In this joint experimental and theoretical analysis, particular focus is put on the crossover between the resonant regime [single-electron tunneling] and the off-resonant regime [inelastic electron (co)tunneling spectroscopy (IETS)]. We show that the interplay of these two processes leads to unexpected mirages of resonances not captured by either of the two pictures alone. Although this turns out to be important in a large fraction of the possible regimes of level positions and bias voltages, it has been given little attention in molecular transport studies. Combined with nonequilibrium IETS—four-electron pump-probe excitations—these mirages provide crucial information on the relaxation of spin excitations. Our encompassing physical picture is supported by a master-equation approach that goes beyond weak coupling. The present work encourages the development of a broader connection between the fields of molecular quantum-dot and scanning probe spectroscopy.

Methods of Generating Key Sequences Based on Parameters of Handwritten Passwords and Signatures

Directory of Open Access Journals (Sweden)

Pavel Lozhnikov

2016-10-01

Full Text Available The modern encryption methods are reliable if strong keys (passwords are used, but the human factor issue cannot be solved by cryptographic methods. The best variant is binding all authenticators (passwords, encryption keys, and others to the identities. When a user is authenticated by biometrical characteristics, the problem of protecting a biometrical template stored on a remote server becomes a concern. The paper proposes several methods of generating keys (passwords by means of the fuzzy extractors method based on signature parameters without storing templates in an open way.

A protection system for picosecond accelerator

International Nuclear Information System (INIS)

Cao Hongping; Chinese Academy of Sciences, Beijing; Chen Huanguang; Xu Ruinian; Tang Junlong; Li Deming

2006-01-01

A personnel and machine protection system for the picosecond accelerator has been built. The key of the system is to send on/off of three triggering signals which are those of electron gun, 2856 MHz and 476 MHz, respectively, to ensure the safety of users and the accelerator. This paper describes the emergencies interlocked by ADAM5511 and timing trigger processor, and some secondary functions which improve the efficiency of the protection system completed in upper layer software. (authors)

Modelling of energetic molecule-surface interactions

International Nuclear Information System (INIS)

Kerford, M.

2000-09-01

This thesis contains the results of molecular dynamics simulations of molecule-surface interactions, looking particularly at fullerene molecules and carbon surfaces. Energetic impacts of fullerene molecules on graphite create defect craters. The relationship between the parameters of the impacting molecule and the parameters of the crater axe examined and found to be a function of the energy and velocity of the impacting molecule. Less energetic fullerene molecules can be scattered from a graphite surface and the partitioning of energy after a scattering event is investigated. It is found that a large fraction of the kinetic energy retained after impact is translational energy, with a small fraction of rotational energy and a number of vibrational modes. At impact energies where the surface is not broken and at normal incidence, surface waves axe seen to occur. These waves axe used to develop a method of desorbing molecules from a graphite surface without damage to either the surface or the molecules being desorbed. A number of fullerene molecules are investigated and ways to increase the desorption yield are examined. It is found that this is a successful technique for desorbing large numbers of intact molecules from graphite. This technique could be used for desorbing intact molecules into a gas phase for mass spectrometric analysis. (author)

Psmir: a database of potential associations between small molecules and miRNAs.

Science.gov (United States)

Meng, Fanlin; Wang, Jing; Dai, Enyu; Yang, Feng; Chen, Xiaowen; Wang, Shuyuan; Yu, Xuexin; Liu, Dianming; Jiang, Wei

2016-01-13

miRNAs are key post-transcriptional regulators of many essential biological processes, and their dysregulation has been validated in almost all human cancers. Restoring aberrantly expressed miRNAs might be a novel therapeutics. Recently, many studies have demonstrated that small molecular compounds can affect miRNA expression. Thus, prediction of associations between small molecules and miRNAs is important for investigation of miRNA-targeted drugs. Here, we analyzed 39 miRNA-perturbed gene expression profiles, and then calculated the similarity of transcription responses between miRNA perturbation and drug treatment to predict drug-miRNA associations. At the significance level of 0.05, we obtained 6501 candidate associations between 1295 small molecules and 25 miRNAs, which included 624 FDA approved drugs. Finally, we constructed the Psmir database to store all potential associations and the related materials. In a word, Psmir served as a valuable resource for dissecting the biological significance in small molecules' effects on miRNA expression, which will facilitate developing novel potential therapeutic targets or treatments for human cancers. Psmir is supported by all major browsers, and is freely available at http://www.bio-bigdata.com/Psmir/.

Integrated Computational Solution for Predicting Skin Sensitization Potential of Molecules.

Directory of Open Access Journals (Sweden)

Konda Leela Sarath Kumar

Full Text Available Skin sensitization forms a major toxicological endpoint for dermatology and cosmetic products. Recent ban on animal testing for cosmetics demands for alternative methods. We developed an integrated computational solution (SkinSense that offers a robust solution and addresses the limitations of existing computational tools i.e. high false positive rate and/or limited coverage.The key components of our solution include: QSAR models selected from a combinatorial set, similarity information and literature-derived sub-structure patterns of known skin protein reactive groups. Its prediction performance on a challenge set of molecules showed accuracy = 75.32%, CCR = 74.36%, sensitivity = 70.00% and specificity = 78.72%, which is better than several existing tools including VEGA (accuracy = 45.00% and CCR = 54.17% with 'High' reliability scoring, DEREK (accuracy = 72.73% and CCR = 71.44% and TOPKAT (accuracy = 60.00% and CCR = 61.67%. Although, TIMES-SS showed higher predictive power (accuracy = 90.00% and CCR = 92.86%, the coverage was very low (only 10 out of 77 molecules were predicted reliably.Owing to improved prediction performance and coverage, our solution can serve as a useful expert system towards Integrated Approaches to Testing and Assessment for skin sensitization. It would be invaluable to cosmetic/ dermatology industry for pre-screening their molecules, and reducing time, cost and animal testing.

The role of adhesive molecules in endometrial cancer: part II

Directory of Open Access Journals (Sweden)

Andrzej Malinowski

2010-12-01

Full Text Available The carcinogenesis is a result of both functional and structural disorders in the tissue. It initiates as a mutationin a gene encoding protein that is essential for cellular function. The subsequent cascade of eventsleads to accumulation of mutations and loss of cellular function. The cell loses its tissue-specific morphology,disconnects from other cells and extracellular matrix and migrates – the invasion begins. It is now clear thatadhesive molecules are a key player in this cascade. These proteins of the cell membrane surface are responsiblefor attachment of the cells to each other and to the extracellular matrix. These interactions are crucial forboth structural and functional tissue organization. Lack of this homeostasis destroys the tissue architectureand impairs its function and results in invasion. Abnormal expression of adhesive molecules was reported in allexamined cancers, including endometrial cancer.Endometrial cancer is the most common gynaecological cancer in developed countries. Although in many casesdiagnosed and treated in early stages, and thus with good results, some patients cannot be cured. Completeknowledge of the pathogenesis of the disease will be helpful in identifying the patients with negative prognosticfactors, increased risk of recurrence and, perhaps, to find other therapeutic options. In the paper we are trying tosum up the up-to-date knowledge of the role of adhesive molecules in pathogenesis of endometrial cancer.

Fabrication and characterization of graphene/molecule/graphene vertical junctions with aryl alkane monolayers

Science.gov (United States)

Jeong, Inho; Song, Hyunwook

2017-11-01

In this study, we fabricated and characterized graphene/molecule/graphene (GMG) vertical junctions with aryl alkane monolayers. The constituent molecules were chemically self-assembled via electrophilic diazonium reactions into a monolayer on the graphene bottom electrode, while the other end physically contacted the graphene top electrode. A full understanding of the transport properties of molecular junctions is a key step in the realization of molecular-scale electronic devices and requires detailed microscopic characterization of the junction's active region. Using a multiprobe approach combining a variety of transport techniques, we elucidated the transport mechanisms and electronic structure of the GMG junctions, including temperature- and length-variable transport measurements, and transition voltage spectroscopy. These results provide criteria to establish a valid molecular junction and to determine the most probable transport characteristics of the GMG junctions.

Cerium fluoride nanoparticles protect cells against oxidative stress

International Nuclear Information System (INIS)

Shcherbakov, Alexander B.; Zholobak, Nadezhda M.; Baranchikov, Alexander E.; Ryabova, Anastasia V.; Ivanov, Vladimir K.

2015-01-01

A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF 3 :Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF 3 nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF 3 and CeF 3 :Tb stable aqueous sols synthesis is proposed. • Naked CeF 3 nanoparticles are shown to be non-toxic and to protect cells from the action of H 2 O 2 . • CeF 3 and CeF 3 :Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus

Cerium fluoride nanoparticles protect cells against oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Shcherbakov, Alexander B.; Zholobak, Nadezhda M. [Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv D0368 (Ukraine); Baranchikov, Alexander E. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ryabova, Anastasia V. [Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow 115409 (Russian Federation); Ivanov, Vladimir K., E-mail: van@igic.ras.ru [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Tomsk State University, Tomsk 634050 (Russian Federation)

2015-05-01

A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF{sub 3}:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF{sub 3} nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF{sub 3} and CeF{sub 3}:Tb stable aqueous sols synthesis is proposed. • Naked CeF{sub 3} nanoparticles are shown to be non-toxic and to protect cells from the action of H{sub 2}O{sub 2}. • CeF{sub 3} and CeF{sub 3}:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus.

Single-molecule dynamics in nanofabricated traps

Science.gov (United States)

Cohen, Adam

2009-03-01

The Anti-Brownian Electrokinetic trap (ABEL trap) provides a means to immobilize a single fluorescent molecule in solution, without surface attachment chemistry. The ABEL trap works by tracking the Brownian motion of a single molecule, and applying feedback electric fields to induce an electrokinetic motion that approximately cancels the Brownian motion. We present a new design for the ABEL trap that allows smaller molecules to be trapped and more information to be extracted from the dynamics of a single molecule than was previously possible. In particular, we present strategies for extracting dynamically fluctuating mobilities and diffusion coefficients, as a means to probe dynamic changes in molecular charge and shape. If one trapped molecule is good, many trapped molecules are better. An array of single molecules in solution, each immobilized without surface attachment chemistry, provides an ideal test-bed for single-molecule analyses of intramolecular dynamics and intermolecular interactions. We present a technology for creating such an array, using a fused silica plate with nanofabricated dimples and a removable cover for sealing single molecules within the dimples. With this device one can watch the shape fluctuations of single molecules of DNA or study cooperative interactions in weakly associating protein complexes.

Single molecules and nanotechnology

CERN Document Server

Vogel, Horst

2007-01-01

This book focuses on recent advances in the rapidly evolving field of single molecule research. These advances are of importance for the investigation of biopolymers and cellular biochemical reactions, and are essential to the development of quantitative biology. Written by leading experts in the field, the articles cover a broad range of topics, including: quantum photonics of organic dyes and inorganic nanoparticles their use in detecting properties of single molecules the monitoring of single molecule (enzymatic) reactions single protein (un)folding in nanometer-sized confined volumes the dynamics of molecular interactions in biological cells The book is written for advanced students and scientists who wish to survey the concepts, techniques and results of single molecule research and assess them for their own scientific activities.

Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL.

Science.gov (United States)

Yang, Yong; Wang, Yan-Fu; Yang, Xiao-Fang; Wang, Zhao-Hui; Lian, Yi-Tian; Yang, Ying; Li, Xiao-Wei; Gao, Xiang; Chen, Jian; Shu, Yan-Wen; Cheng, Long-Xian; Liao, Yu-Hua; Liu, Kun

2013-01-01

Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions.

A study on interaction of DNA molecules and carbon nanotubes for an effective ejection of the molecules

International Nuclear Information System (INIS)

Wu, N.; Wang, Q.

2012-01-01

The ejection of DNA molecules from carbon nanotubes is reported from interaction energy perspectives by molecular dynamics simulations. The critical ejection energy, which is to be applied to a DNA molecule for a successful ejection from a carbon nanotube, is investigated based on a study on the friction and binding energy between the DNA molecule and the tube. An effective ejection is realized by subjecting a kinetic energy on the DNA molecule that is larger than the solved critical ejection energy. In addition, the relationship between ejection energies and sizes of DNA molecules and carbon nanotubes is investigated. -- Highlights: ► Report the ejection of DNA molecules from CNTs from interaction energy perspectives. ► Develop a methodology for the critical energy of an effective ejection of a DNA molecule from a CNT. ► Present the relationship between critical ejection energies and sizes of DNA molecules and CNTs. ► Provide a general guidance on the ejection of encapsulated molecules from CNTs.

Organizing and addressing magnetic molecules.

Science.gov (United States)

Gatteschi, Dante; Cornia, Andrea; Mannini, Matteo; Sessoli, Roberta

2009-04-20

Magnetic molecules ranging from simple organic radicals to single-molecule magnets (SMMs) are intensively investigated for their potential applications in molecule-based information storage and processing. The goal of this Article is to review recent achievements in the organization of magnetic molecules on surfaces and in their individual probing and manipulation. We stress that the inherent fragility and redox sensitivity of most SMM complexes, combined with the noninnocent role played by the substrate, ask for a careful evaluation of the structural and electronic properties of deposited molecules going beyond routine methods for surface analysis. Detailed magnetic information can be directly obtained using X-ray magnetic circular dichroism or newly emerging scanning probe techniques with magnetic detection capabilities.

Quantification and Sequencing of Crossover Recombinant Molecules from Arabidopsis Pollen DNA.

Science.gov (United States)

Choi, Kyuha; Yelina, Nataliya E; Serra, Heïdi; Henderson, Ian R

2017-01-01

During meiosis, homologous chromosomes undergo recombination, which can result in formation of reciprocal crossover molecules. Crossover frequency is highly variable across the genome, typically occurring in narrow hotspots, which has a significant effect on patterns of genetic diversity. Here we describe methods to measure crossover frequency in plants at the hotspot scale (bp-kb), using allele-specific PCR amplification from genomic DNA extracted from the pollen of F 1 heterozygous plants. We describe (1) titration methods that allow amplification, quantification and sequencing of single crossover molecules, (2) quantitative PCR methods to more rapidly measure crossover frequency, and (3) application of high-throughput sequencing for study of crossover distributions within hotspots. We provide detailed descriptions of key steps including pollen DNA extraction, prior identification of hotspot locations, allele-specific oligonucleotide design, and sequence analysis approaches. Together, these methods allow the rate and recombination topology of plant hotspots to be robustly measured and compared between varied genetic backgrounds and environmental conditions.

Small-Molecule Inhibitors Targeting DNA Repair and DNA Repair Deficiency in Research and Cancer Therapy.

Science.gov (United States)

Hengel, Sarah R; Spies, M Ashley; Spies, Maria

2017-09-21

To maintain stable genomes and to avoid cancer and aging, cells need to repair a multitude of deleterious DNA lesions, which arise constantly in every cell. Processes that support genome integrity in normal cells, however, allow cancer cells to develop resistance to radiation and DNA-damaging chemotherapeutics. Chemical inhibition of the key DNA repair proteins and pharmacologically induced synthetic lethality have become instrumental in both dissecting the complex DNA repair networks and as promising anticancer agents. The difficulty in capitalizing on synthetically lethal interactions in cancer cells is that many potential targets do not possess well-defined small-molecule binding determinates. In this review, we discuss several successful campaigns to identify and leverage small-molecule inhibitors of the DNA repair proteins, from PARP1, a paradigm case for clinically successful small-molecule inhibitors, to coveted new targets, such as RAD51 recombinase, RAD52 DNA repair protein, MRE11 nuclease, and WRN DNA helicase. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecule-by-Molecule Writing Using a Focused Electron Beam

DEFF Research Database (Denmark)

Van Dorp, Willem F.; Zhang, Xiaoyan; Feringa, Ben L.

2012-01-01

atoms also be written with an electron beam? We verify this with focused electron-beam-induced deposition (FEBID), a direct-write technique that has the current record for the smallest feature written by (electron) optical lithography. We show that the deposition of an organometallic precursor...... on graphene can be followed molecule-by-molecule with FEBID. The results show that mechanisms that are inherent to the process inhibit a further increase in control over the process. Hence, our results present the resolution limit of (electron) optical lithography techniques. The writing of isolated...

Reconstruction method for data protection in telemedicine systems

Science.gov (United States)

Buldakova, T. I.; Suyatinov, S. I.

2015-03-01

In the report the approach to protection of transmitted data by creation of pair symmetric keys for the sensor and the receiver is offered. Since biosignals are unique for each person, their corresponding processing allows to receive necessary information for creation of cryptographic keys. Processing is based on reconstruction of the mathematical model generating time series that are diagnostically equivalent to initial biosignals. Information about the model is transmitted to the receiver, where the restoration of physiological time series is performed using the reconstructed model. Thus, information about structure and parameters of biosystem model received in the reconstruction process can be used not only for its diagnostics, but also for protection of transmitted data in telemedicine complexes.

Observation of pendular butterfly Rydberg molecules

Science.gov (United States)

Niederprüm, Thomas; Thomas, Oliver; Eichert, Tanita; Lippe, Carsten; Pérez-Ríos, Jesús; Greene, Chris H.; Ott, Herwig

2016-01-01

Engineering molecules with a tunable bond length and defined quantum states lies at the heart of quantum chemistry. The unconventional binding mechanism of Rydberg molecules makes them a promising candidate to implement such tunable molecules. A very peculiar type of Rydberg molecules are the so-called butterfly molecules, which are bound by a shape resonance in the electron–perturber scattering. Here we report the observation of these exotic molecules and employ their exceptional properties to engineer their bond length, vibrational state, angular momentum and orientation in a small electric field. Combining the variable bond length with their giant dipole moment of several hundred Debye, we observe counter-intuitive molecules which locate the average electron position beyond the internuclear distance. PMID:27703143

Passing Current through Touching Molecules

DEFF Research Database (Denmark)

Schull, G.; Frederiksen, Thomas; Brandbyge, Mads

2009-01-01

The charge flow from a single C-60 molecule to another one has been probed. The conformation and electronic states of both molecules on the contacting electrodes have been characterized using a cryogenic scanning tunneling microscope. While the contact conductance of a single molecule between two...

Elucidating the Key Role of a Lewis Base Solvent in the Formation of Perovskite Films Fabricated from the Lewis Adduct Approach.

Science.gov (United States)

Cao, Xiaobing; Zhi, Lili; Li, Yahui; Fang, Fei; Cui, Xian; Yao, Youwei; Ci, Lijie; Ding, Kongxian; Wei, Jinquan

2017-09-27

High-quality perovskite films can be fabricated from Lewis acid-base adducts through molecule exchange. Substantial work is needed to fully understand the formation mechanism of the perovskite films, which helps to further improve their quality. Here, we study the formation of CH 3 NH 3 PbI 3 perovskite films by introducing some dimethylacetamide into the PbI 2 /N,N-dimethylformamide solution. We reveal that there are three key processes during the formation of perovskite films through the Lewis acid-base adduct approach: molecule intercalation of solvent into the PbI 2 lattice, molecule exchange between the solvent and CH 3 NH 3 I, and dissolution-recrystallization of the perovskite grains during annealing. The Lewis base solvents play multiple functions in the above processes. The properties of the solvent, including Lewis basicity and boiling point, play key roles in forming smooth perovskite films with large grains. We also provide some rules for choosing Lewis base additives to prepare high-quality perovskite films through the Lewis adduct approach.

Protection of aliphatic alcohols by thiols

International Nuclear Information System (INIS)

Nanobashivili, E.M.; Chirakadze, G.G.; Panchvidze, M.V.; Gvilava, S.E.; Khidesheli, G.I.

1973-01-01

Study was made of methyl, ethyl, propyl, butyl and penthyl alcohols. The aqueous solutions of the alcohols were X-irradiated. Results are presented of the action of high-energy particles on the solutions of ethyl, propyl and butyl alcohols in the presence and absence of the minor amounts of ethanthiol. Protective effect of the -SH group was established. Addition of 1.10 -6 mol/1 of ethanthiol to butyl alcohol protects it completely against radiation conversions up to a dose of 8.10 19 eV/ml. Consideration is given to the effect of thioalcohol additives on the formation of some products of alcohol radiation oxidation. Introduction of mercaptans to the system or that of the -SH group to the organic compound molecule enhances its radiation resistance [ru

Coenzyme protection of lactic dehydrogenase against inactivation by gamma-rays

International Nuclear Information System (INIS)

Saito, M.

1978-01-01

A comparison has been made of the radiation sensitivities of the ternary complexes, oxamate-LDH-NADH and pyruvate-LDH-NAD with those of free LDH molecules and the intermediate binary complexes LDH-NAD and LDH-NADH. The enzyme solutions were 60 Co γirradiated and the rate of pyruvate reduction then measured. At doses of more than 10 krad the coenzymes afforded considerable protection to LDH against inactivation, and the dose-effect curves deviated from the curve for the unprotected enzyme, implying very specific protection. Coenzyme protection for a 30 krad dose at various concentrations of NAD and NADH reached a saturation level at about 4.0 x 10 -4 M for both NAD and NADH; protection by pyruvate alone was slight in comparison. Pyruvate and NAD (or oxamate and NADH) together at 1.0 x 10 -3 M protected the enzyme in a cooperative way. The results suggest that the major events of protection occur on the substrate and coenzyme binding sites, and support the view that coenzyme binding protects the enzyme by altering its conformation. (U.K.)

A Lightweight Authentication and Key Management Scheme for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Danyang Qin

2016-01-01

Full Text Available Security problem is one of the most popular research fields in wireless sensor networks for both the application requirement and the resource-constrained essence. An effective and lightweight Authentication and Key Management Scheme (AKMS is proposed in this paper to solve the problem of malicious nodes occurring in the process of networking and to offer a high level of security with low cost. For the condition that the mobile sensor nodes need to be authenticated, the keys in AKMS will be dynamically generated and adopted for security protection. Even when the keys are being compromised or captured, the attackers can neither use the previous keys nor misuse the authenticated nodes to cheat. Simulation results show that the proposed scheme provides more efficient security with less energy consumption for wireless sensor networks especially with mobile sensors.

Physical implementation of protected qubits

International Nuclear Information System (INIS)

Douçot, B; Ioffe, L B

2012-01-01

We review the general notion of topological protection of quantum states in spin models and its relation with the ideas of quantum error correction. We show that topological protection can be viewed as a Hamiltonian realization of error correction: for a quantum code for which the minimal number of errors that remain undetected is N, the corresponding Hamiltonian model of the effects of the environment noise appears only in the Nth order of the perturbation theory. We discuss the simplest model Hamiltonians that realize topological protection and their implementation in superconducting arrays. We focus on two dual realizations: in one the protected state is stored in the parity of the Cooper pair number, in the other, in the parity of the flux number. In both cases the superconducting arrays allow a number of fault-tolerant operations that should make the universal quantum computation possible. (key issues reviews)

Efficient Key Management System for Large-scale Smart RFID Applications

Directory of Open Access Journals (Sweden)

Mohammad Fal Sadikin

2015-08-01

Full Text Available Due to low-cost and its practical solution, the integration of RFID tag to the sensor node called smart RFID has become prominent solution in various fields including industrial applications. Nevertheless, the constrained nature of smart RFID system introduces tremendous security and privacy problem. One of them is the problem in key management system. Indeed, it is not feasible to recall all RFID tags in order to update their security properties (e.g. update their private keys. On the other hand, using common key management solution like standard TLS/SSL is too heavy-weight that can drain and overload the limited resources. Furthermore, most of existing solutions are highly susceptible to various threats reaching from privacy threats, physical attacks to various technics of Man-in-the-Middle attacks. This paper introduces novel key management system, tailored to the limited resources of smart RFID system. It proposes light-weight mutual authentication and identity protection to mitigate the existing threats.

Insulator-protected mechanically controlled break junctions for measuring single-molecule conductance in aqueous environments

Science.gov (United States)

Muthusubramanian, N.; Galan, E.; Maity, C.; Eelkema, R.; Grozema, F. C.; van der Zant, H. S. J.

2016-07-01

We present a method to fabricate insulated gold mechanically controlled break junctions (MCBJ) by coating the metal with a thin layer of aluminum oxide using plasma enhanced atomic layer deposition. The Al2O3 thickness deposited on the MCBJ devices was varied from 2 to 15 nm to test the suppression of leakage currents in deionized water and phosphate buffered saline. Junctions coated with a 15 nm thick oxide layer yielded atomically sharp electrodes and negligible conductance counts in the range of 1 to 10-4 G0 (1 G0 = 77 μS), where single-molecule conductances are commonly observed. The insulated devices were used to measure the conductance of an amphiphilic oligophenylene ethynylene derivative in deionized water.

Enzyme Molecules in Solitary Confinement

Directory of Open Access Journals (Sweden)

Raphaela B. Liebherr

2014-09-01

Full Text Available Large arrays of homogeneous microwells each defining a femtoliter volume are a versatile platform for monitoring the substrate turnover of many individual enzyme molecules in parallel. The high degree of parallelization enables the analysis of a statistically representative enzyme population. Enclosing individual enzyme molecules in microwells does not require any surface immobilization step and enables the kinetic investigation of enzymes free in solution. This review describes various microwell array formats and explores their applications for the detection and investigation of single enzyme molecules. The development of new fabrication techniques and sensitive detection methods drives the field of single molecule enzymology. Here, we introduce recent progress in single enzyme molecule analysis in microwell arrays and discuss the challenges and opportunities.

Phase Structure of Strong-Field Tunneling Wave Packets from Molecules.

Science.gov (United States)

Liu, Ming-Ming; Li, Min; Wu, Chengyin; Gong, Qihuang; Staudte, André; Liu, Yunquan

2016-04-22

We study the phase structure of the tunneling wave packets from strong-field ionization of molecules and present a molecular quantum-trajectory Monte Carlo model to describe the laser-driven dynamics of photoelectron momentum distributions of molecules. Using our model, we reproduce and explain the alignment-dependent molecular frame photoelectron spectra of strong-field tunneling ionization of N_{2} reported by M. Meckel et al. [Nat. Phys. 10, 594 (2014)]. In addition to modeling the low-energy photoelectron angular distributions quantitatively, we extract the phase structure of strong-field molecular tunneling wave packets, shedding light on its physical origin. The initial phase of the tunneling wave packets at the tunnel exit depends on both the initial transverse momentum distribution and the molecular internuclear distance. We further show that the ionizing molecular orbital has a critical effect on the initial phase of the tunneling wave packets. The phase structure of the photoelectron wave packet is a key ingredient for modeling strong-field molecular photoelectron holography, high-harmonic generation, and molecular orbital imaging.

A Mott-like State of Molecules

International Nuclear Information System (INIS)

Duerr, S.; Volz, T.; Syassen, N.; Bauer, D. M.; Hansis, E.; Rempe, G.

2006-01-01

We prepare a quantum state where each site of an optical lattice is occupied by exactly one molecule. This is the same quantum state as in a Mott insulator of molecules in the limit of negligible tunneling. Unlike previous Mott insulators, our system consists of molecules which can collide inelastically. In the absence of the optical lattice these collisions would lead to fast loss of the molecules from the sample. To prepare the state, we start from a Mott insulator of atomic 87Rb with a central region, where each lattice site is occupied by exactly two atoms. We then associate molecules using a Feshbach resonance. Remaining atoms can be removed using blast light. Our method does not rely on the molecule-molecule interaction properties and is therefore applicable to many systems

Dissociation in small molecules

International Nuclear Information System (INIS)

Dehmer, P.M.

1982-01-01

The study of molecular dissociation processes is one of the most interesting areas of modern spectroscopy owing to the challenges presented bt even the simplest of diatomic molecules. This paper reviews the commonly used descriptions of molecular dissociation processes for diatomic molecules, the selection rules for predissociation, and a few of the principles to be remembered when one is forced to speculate about dissociation mechanisms in a new molecule. Some of these points will be illustrated by the example of dissociative ionization in O 2

Community Involvement in Marine Protected Areas.

Science.gov (United States)

Kaza, Stephanie

1988-01-01

Lists several key concepts in developing successful interpretive programs for marine protected areas with community involvement. Identifies educational tools that help foster community involvement in conservation and management. Cites three model programs. Sets standards and goals for international success including leadership, education,…

Legislation on violence against women: overview of key components.

Science.gov (United States)

Ortiz-Barreda, Gaby; Vives-Cases, Carmen

2013-01-01

This study aimed to determine if legislation on violence against women (VAW) worldwide contains key components recommended by the Pan American Health Organization (PAHO) and the United Nations (UN) to help strengthen VAW prevention and provide better integrated victim protection, support, and care. A systematic search for VAW legislation using international legal databases and other electronic sources plus data from previous research identified 124 countries/territories with some type of VAW legislation. Full legal texts were found for legislation from 104 countries/territories. Those available in English, Portuguese, and Spanish were downloaded and compiled and the selection criteria applied (use of any of the common terms related to VAW, including intimate partner violence (IPV), and reference to at least two of six sectors (education, health, judicial system, mass media, police, and social services) with regard to VAW interventions (protection, support, and care). A final sample from 80 countries/territories was selected and analyzed for the presence of key components recommended by PAHO and the UN (reference to the term "violence against women" in the title; definitions of different types of VAW; identification of women as beneficiaries; and promotion of (reference to) the participation of multiple sectors in VAW interventions). Few countries/territories specifically identified women as the beneficiaries of their VAW legislation, including those that labeled their legislation "domestic violence" law ( n = 51), of which only two explicitly mentioned women as complainants/survivors. Only 28 countries/territories defined the main forms of VAW (economic, physical, psychological, and sexual) in their VAW legislation. Most highlighted the role of the judicial system, followed by that of social services and the police. Only 28 mentioned the health sector. Despite considerable efforts worldwide to strengthen VAW legislation, most VAW laws do not incorporate the key

The work of ICRP on the ethical foundations of the system of radiological protection

International Nuclear Information System (INIS)

Cho, Kun-Woo

2017-01-01

The International Commission on Radiological Protection (ICRP) has established Task Group 94 (TG 94) to develop a publication on the ethical foundations of the system of radiological protection aiming to consolidate the basis of ICRP's recommendations, to improve the understanding of the system and to provide a basis for communication on radiation risk and its perception. Through the review of the publications of the Commission and the conduct of a series of workshops, TG 94 has identified the key components of the ethical theories and principles relevant to the system of radiological protection. The purpose of eliciting the ethical values underpinning the system of radiological protection is not only to clarify the rationale of the recommendations made by the Commission, but also to assist in discussions related to its practical implementation. The report nearing completion by TG 94 will present the key steps concerning the scientific, ethical and practical evolutions of the system of radiological protection since the first ICRP publication in 1928, describe the core ethical values underpinning the present system and address the key procedural aspects for its implementation. (authors)

Molecular Regulation of Adipogenesis and Potential Anti-Adipogenic Bioactive Molecules

Directory of Open Access Journals (Sweden)

Dorothy Moseti

2016-01-01

Full Text Available Adipogenesis is the process by which precursor stem cells differentiate into lipid laden adipocytes. Adipogenesis is regulated by a complex and highly orchestrated gene expression program. In mammalian cells, the peroxisome proliferator-activated receptor γ (PPARγ, and the CCAAT/enhancer binding proteins (C/EBPs such as C/EBPα, β and δ are considered the key early regulators of adipogenesis, while fatty acid binding protein 4 (FABP4, adiponectin, and fatty acid synthase (FAS are responsible for the formation of mature adipocytes. Excess accumulation of lipids in the adipose tissue leads to obesity, which is associated with cardiovascular diseases, type II diabetes and other pathologies. Thus, investigating adipose tissue development and the underlying molecular mechanisms is vital to develop therapeutic agents capable of curbing the increasing incidence of obesity and related pathologies. In this review, we address the process of adipogenic differentiation, key transcription factors and proteins involved, adipogenic regulators and potential anti-adipogenic bioactive molecules.

Protective Skins for Composite Airliners

Science.gov (United States)

Johnson, Vicki S.; Boone, Richard L.; Jones, Shannon; Pendse, Vandana; Hayward, Greg

2014-01-01

Traditional composite aircraft structures are designed for load bearing and then overdesigned for impact damage and hot humid environments. Seeking revolutionary improvement in the performance and weight of composite structures, Cessna Aircraft Company, with sponsorship from the NASA Fundamental Aeronautics Program/Subsonic Fixed Wing Project, has developed and tested a protective skin concept which would allow the primary composite structure to carry only load and would meet the impact, hot and humid, and other requirements through protective skins. A key requirement for the protective skins is to make any impact damage requiring repair visible. Testing from the first generation of skins helped identify the most promising materials which were used in a second generation of test articles. This report summarizes lessons learned from the first generation of protective skins, the design and construction of the second-generation test articles, test results from the second generation for impact, electromagnetic effects, aesthetics and smoothing, thermal, and acoustic (for the first time), and an assessment of the feasibility of the protective skin concept.

Celastrol Protects against Antimycin A-Induced Insulin Resistance in Human Skeletal Muscle Cells

Directory of Open Access Journals (Sweden)

Mohamad Hafizi Abu Bakar

2015-05-01

Full Text Available Mitochondrial dysfunction and inflammation are widely accepted as key hallmarks of obesity-induced skeletal muscle insulin resistance. The aim of the present study was to evaluate the functional roles of an anti-inflammatory compound, celastrol, in mitochondrial dysfunction and insulin resistance induced by antimycin A (AMA in human skeletal muscle cells. We found that celastrol treatment improved insulin-stimulated glucose uptake activity of AMA-treated cells, apparently via PI3K/Akt pathways, with significant enhancement of mitochondrial activities. Furthermore, celastrol prevented increased levels of cellular oxidative damage where the production of several pro-inflammatory cytokines in cultures cells was greatly reduced. Celastrol significantly increased protein phosphorylation of insulin signaling cascades with amplified expression of AMPK protein and attenuated NF-κB and PKC θ activation in human skeletal muscle treated with AMA. The improvement of insulin signaling pathways by celastrol was also accompanied by augmented GLUT4 protein expression. Taken together, these results suggest that celastrol may be advocated for use as a potential therapeutic molecule to protect against mitochondrial dysfunction-induced insulin resistance in human skeletal muscle cells.

Phi ({Phi}) and psi ({Psi}) angles involved in malarial peptide bonds determine sterile protective immunity

Energy Technology Data Exchange (ETDEWEB)

Patarroyo, Manuel E., E-mail: mepatarr@gmail.com [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Universidad Nacional de Colombia, Bogota (Colombia); Moreno-Vranich, Armando; Bermudez, Adriana [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia)

2012-12-07

Highlights: Black-Right-Pointing-Pointer Phi ({Phi}) and psi ({Psi}) angles determine sterile protective immunity. Black-Right-Pointing-Pointer Modified peptide's tendency to assume a regular conformation related to a PPII{sub L}. Black-Right-Pointing-Pointer Structural modifications in mHABPs induce Ab and protective immunity. Black-Right-Pointing-Pointer mHABP backbone atom's interaction with HLA-DR{beta}1{sup Asterisk-Operator} is stabilised by H-bonds. -- Abstract: Modified HABP (mHABP) regions interacting with HLA-DR{beta}1{sup Asterisk-Operator} molecules have a more restricted conformation and/or sequence than other mHABPs which do not fit perfectly into their peptide binding regions (PBR) and do not induce an acceptable immune response due to the critical role of their {Phi} and {Psi} torsion angles. These angle's critical role was determined in such highly immunogenic, protection-inducing response against experimental malaria using the conformers (mHABPs) obtained by {sup 1}H-NMR and superimposed into HLA-DR{beta}1{sup Asterisk-Operator }-like Aotus monkey molecules; their phi ({Phi}) and psi ({Psi}) angles were measured and the H-bond formation between these molecules was evaluated. The aforementioned mHABP propensity to assume a regular conformation similar to a left-handed polyproline type II helix (PPII{sub L}) led to suggesting that favouring these conformations according to their amino acid sequence would lead to high antibody titre production and sterile protective immunity induction against malaria, thereby adding new principles or rules for vaccine development, malaria being one of them.

Neutral molecules in tokamak edge plasma - role of vibrationally excited hydrogen molecules

International Nuclear Information System (INIS)

Cadez, I.; Cercek, M.; Pelicon, P.; Razpet, A.

2003-01-01

The role of neutral molecules in edge plasma is discussed with special emphasis on the vibrationally excited hydrogen. Neutral molecules are formed mostly by surface processes on the walls and then released to the edge plasma where they take part in volumetric reactions with other particles. Typically these molecules are formed in excited states and data are needed for their reactions on the wall and in the volume. Processes in edge plasma determine particle and energy flux what is especially critical issue in tokamak divertor region. Various cross sections and reaction rates are needed for modelling edge plasma and its interaction with walls. (author)

Single Molecule Analysis Research Tool (SMART: an integrated approach for analyzing single molecule data.

Directory of Open Access Journals (Sweden)

Max Greenfeld

Full Text Available Single molecule studies have expanded rapidly over the past decade and have the ability to provide an unprecedented level of understanding of biological systems. A common challenge upon introduction of novel, data-rich approaches is the management, processing, and analysis of the complex data sets that are generated. We provide a standardized approach for analyzing these data in the freely available software package SMART: Single Molecule Analysis Research Tool. SMART provides a format for organizing and easily accessing single molecule data, a general hidden Markov modeling algorithm for fitting an array of possible models specified by the user, a standardized data structure and graphical user interfaces to streamline the analysis and visualization of data. This approach guides experimental design, facilitating acquisition of the maximal information from single molecule experiments. SMART also provides a standardized format to allow dissemination of single molecule data and transparency in the analysis of reported data.

Relative contributions of decay accelerating factor (DAF), membrane cofactor protein (MCP) and CD59 in the protection of melanocytes from homologous complement

NARCIS (Netherlands)

Venneker, G. T.; Vodegel, R. M.; Okada, N.; Westerhof, W.; Bos, J. D.; Asghar, S. S.

1998-01-01

Complement regulatory molecules, membrane cofactor protein (MCP), decay accelerating factor (DAF) and CD59, protect body cells from autologous complement. They have wide tissue distribution but nothing is known about the expression of these molecules on human melanocytes. Since melanocytes are lysed

Promoting radiation protection in France and Europe. The key role of IRSN, French Technical Safety Organisation

Energy Technology Data Exchange (ETDEWEB)

Repussard, Jacques [IRSN - Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses (France). Direction des Affaires Internationales - Delegation aux Relations Internationales

2012-07-01

IRSN, the Institute for Radiological Protection and Nuclear Safety was set up in France under Article 5 of French Act No. 2001-398 of May 9, 2001 as the French 'Technical Safety Organization' (TSO) expert in nuclear and radiological risks. It contributes to the implementation of public policies concerning nuclear safety and security and protection of human health and environment against ionizing radiation. IRSN interacts with all the parties concerned by these policies (public authorities, operators and stakeholders) while keeping its independence of judgment. (orig.)

Increased Expression of Intercellular Adhesion Molecule-1, Vascular Cellular Adhesion Molecule-1 and Leukocyte Common Antigen in Diabetic Rat Retina

Institute of Scientific and Technical Information of China (English)

Ningyan Bai; Shibo Tang; Jing Ma; Yan Luo; Shaofeng Lin

2003-01-01

Purpose: To understand the expression and distribution of intercellular adhesion molecule- 1(ICAM- 1),vascular cellular adhesion molecule- 1 (VCAM- 1)and CD45 (Leukocyte Common Antigen) in the control nondiabetic and various courses of diabetic rats retina. To explore the role of adhesion molecules (Ams) and the adhesion of leukocytes to vascular endothelial cells via Ams in diabetic retinopathy(DR).Methods: Sixty healthy adult male Wistar rats were randomly divided into diabetic groups(induced by Streptozotocin, STZ) and normal control groups. Rats in these two groups were further randomly divided into 3, 7, 14, 30, 90 and 180 days-group,including 5 rats respectively. The immunohistochemical studies of ICAM-1, VCAM-1 and CD45 were carried out in the retinal digest preparations or retinal paraffin sections, and the results were analyzed qualitatively, semi-quantitatively.Results: No positive reaction of VCAM-1 was found, and weak reactions of ICAM-1,CD45 were found in nondiabetic rats retina. The difference of 6 control groups had no statistical significance(P ＞ 0.05). The increased ICAM-1 and CD45 staining pattern were detectable 3 days after diabetes induction, and a few VCAM-1 positive cells were observed in the retinal blood capillaries. The difference of diabetes and control is significant( P ＜ 0.05).Following the course, the expressions of ICAM-1, VCAM-1 and CD45 were increasingly enhanced, reaching a peak at the 14th day.Conclusion: Increased expression of ICAM-1, VCAM-1 and leukocytes adhering and stacking in retinal capillaries are the very early events in DR. Coherence of expression and distribution of the three further accounts for it is the key point for the onset of DR that Ams mediates leukocytes adhesion and endothelial cell injury.

Antihypertrophic Effects of Small Molecules that Maintain Mitochondrial ATP Levels Under Hypoxia

Directory of Open Access Journals (Sweden)

Hiroaki Nagai

2017-10-01

Full Text Available Since impaired mitochondrial ATP production in cardiomyocytes is thought to lead to heart failure, a drug that protects mitochondria and improves ATP production under disease conditions would be an attractive treatment option. In this study, we identified small-molecule drugs, including the anti-parasitic agent, ivermectin, that maintain mitochondrial ATP levels under hypoxia in cardiomyocytes. Mechanistically, transcriptomic analysis and gene silencing experiments revealed that ivermectin increased mitochondrial ATP production by inducing Cox6a2, a subunit of the mitochondrial respiratory chain. Furthermore, ivermectin inhibited the hypertrophic response of human induced pluripotent stem cell-derived cardiomyocytes. Pharmacological inhibition of importin β, one of the targets of ivermectin, exhibited protection against mitochondrial ATP decline and cardiomyocyte hypertrophy. These findings indicate that maintaining mitochondrial ATP under hypoxia may prevent hypertrophy and improve cardiac function, providing therapeutic options for mitochondrial dysfunction.

Radiation Protection at Light Water Reactors

CERN Document Server

Prince, Robert

2012-01-01

This book is aimed at Health Physicists wishing to gain a better understanding of the principles and practices associated with a light water reactor (LWR) radiation protection program. The role of key program elements is presented in sufficient detail to assist practicing radiation protection professionals in improving and strengthening their current program. Details related to daily operation and discipline areas vital to maintaining an effective LWR radiation protection program are presented. Programmatic areas and functions important in preventing, responding to, and minimizing radiological incidents and the importance of performing effective incident evaluations and investigations are described. Elements that are integral in ensuring continuous program improvements are emphasized throughout the text.

Insulator-protected mechanically controlled break junctions for measuring single-molecule conductance in aqueous environments

Energy Technology Data Exchange (ETDEWEB)

Muthusubramanian, N.; Zant, H. S. J. van der [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Galan, E.; Maity, C.; Eelkema, R.; Grozema, F. C. [Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft (Netherlands)

2016-07-04

We present a method to fabricate insulated gold mechanically controlled break junctions (MCBJ) by coating the metal with a thin layer of aluminum oxide using plasma enhanced atomic layer deposition. The Al{sub 2}O{sub 3} thickness deposited on the MCBJ devices was varied from 2 to 15 nm to test the suppression of leakage currents in deionized water and phosphate buffered saline. Junctions coated with a 15 nm thick oxide layer yielded atomically sharp electrodes and negligible conductance counts in the range of 1 to 10{sup −4} G{sub 0} (1 G{sub 0} = 77 μS), where single-molecule conductances are commonly observed. The insulated devices were used to measure the conductance of an amphiphilic oligophenylene ethynylene derivative in deionized water.

The Quest for Nanoscale Magnets: The example of [Mn12] Single Molecule Magnets.

Science.gov (United States)

Rogez, Guillaume; Donnio, Bertrand; Terazzi, Emmanuel; Gallani, Jean-Louis; Kappler, Jean-Paul; Bucher, Jean-Pierre; Drillon, Marc

2009-11-20

Recent advances on the organization and characterization of [Mn12] single molecule magnets (SMMs) on a surface or in 3D are reviewed. By using nonconventional techniques such as X-ray magnetic circular dichroism (XMCD) and scanning tunneling microscopy (STM), it is shown that [Mn12]-based SMMs deposited on a surface lose their SMM behavior, even though the molecules seem to be structurally undamaged. A new approach is reported to get high-density information-storage devices, based on the 3D assembling of SMMs in a liquid crystalline phase. The 3D nanostructure exhibits the anisotropic character of the SMMs, thus opening the way to address micrometric volumes by two photon absorption using the pump-probe technique. We present recent developments such as µ-SQUID, magneto-optical Kerr effect (MOKE), or magneto-optical circular dichroism (MOCD), which enable the characterization of SMM nanostructures with exceptional sensitivity. Further, the spin-polarized version of the STM under ultrahigh vacuum is shown to be the key tool for addressing not only single molecule magnets, but also magnetic nano-objects. Copyright © 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Exotic helium molecules

International Nuclear Information System (INIS)

Portier, M.

2007-12-01

We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range 4 He 2 (2 3 S 1 -2 3 P 0 ) molecule, or a 4 He 2 (2 3 S 1 -2 3 S 1 ) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 ± 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range 4 He 2 (2 3 S 1 -2 3 S 1 ) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime τ = (1.4 ± 0.3) μs is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

Phi (Φ) and psi (Ψ) angles involved in malarial peptide bonds determine sterile protective immunity.

Science.gov (United States)

Patarroyo, Manuel E; Moreno-Vranich, Armando; Bermúdez, Adriana

2012-12-07

Modified HABP (mHABP) regions interacting with HLA-DRβ1(∗) molecules have a more restricted conformation and/or sequence than other mHABPs which do not fit perfectly into their peptide binding regions (PBR) and do not induce an acceptable immune response due to the critical role of their Φ and Ψ torsion angles. These angle's critical role was determined in such highly immunogenic, protection-inducing response against experimental malaria using the conformers (mHABPs) obtained by (1)H-NMR and superimposed into HLA-DRβ1(∗)-like Aotus monkey molecules; their phi (Φ) and psi (Ψ) angles were measured and the H-bond formation between these molecules was evaluated. The aforementioned mHABP propensity to assume a regular conformation similar to a left-handed polyproline type II helix (PPII(L)) led to suggesting that favouring these conformations according to their amino acid sequence would lead to high antibody titre production and sterile protective immunity induction against malaria, thereby adding new principles or rules for vaccine development, malaria being one of them. Copyright © 2012 Elsevier Inc. All rights reserved.

Cold guided beams of polar molecules

International Nuclear Information System (INIS)

Motsch, Michael

2010-01-01

This thesis reports on experiments characterizing cold guided beams of polar molecules which are produced by electrostatic velocity filtering. This filtering method exploits the interaction between the polar molecules and the electric field provided by an electrostatic quadrupole guide to extract efficiently the slow molecules from a thermal reservoir. For molecules with large and linear Stark shifts such as deuterated ammonia (ND 3 ) or formaldehyde (H 2 CO), fluxes of guided molecules of 10 10 -10 11 molecules/s are produced. The velocities of the molecules in these beams are in the range of 10-200 m/s and correspond to typical translational temperatures of a few Kelvin. The maximum velocity of the guided molecules depends on the Stark shift, the molecular mass, the geometry of the guide, and the applied electrode voltage. Although the source is operated in the near-effusive regime, the number density of the slowest molecules is sensitive to collisions. A theoretical model, taking into account this velocity-dependent collisional loss of molecules in the vicinity of the nozzle, reproduces the density of the guided molecules over a wide pressure range. A careful adjustment of pressure allows an increase in the total number of molecules, whilst yet minimizing losses due to collisions of the sought-for slow molecules. This is an important issue for future applications. Electrostatic velocity filtering is suited for different molecular species. This is demonstrated by producing cold guided beams of the water isotopologs H 2 O, D 2 O, and HDO. Although these are chemically similar, they show linear and quadratic Stark shifts, respectively, when exposed to external electric fields. As a result, the flux of HDO is larger by one order of magnitude, and the flux of the individual isotopologs shows a characteristic dependence on the guiding electric field. The internal-state distribution of guided molecules is studied with a newly developed diagnostic method: depletion

Evaluation of the South African surrogate leg for landmine protection injury measurements

CSIR Research Space (South Africa)

Pandelani, T

2010-01-01

Full Text Available For troop mobility and safety during peacekeeping operations, protection against landmines is key. Vehicle landmine protection validation testing is an integral part of military equipment procurement process and serves as an important technical...

Friends and foes of tuberculosis: modulation of protective immunity.

Science.gov (United States)

Brighenti, Susanna; Joosten, Simone A

2018-05-27

Protective immunity in tuberculosis (TB) is subject of debate in the TB research community, as this is key to fully understand TB pathogenesis and to develop new promising tools for TB diagnosis and prognosis as well as a more efficient TB vaccine. IFN-γ producing CD4 + T cells are key in TB control, but may not be sufficient to provide protection. Additional subsets have been identified that contribute to protection such as multifunctional and cytolytic T cell subsets, including classical and non-classical T cells as well as novel innate immune cell subsets resulting from trained immunity. However, to define protective immune responses against TB, the complexity of balancing TB immunity also has to be considered. In this review, insights in effector cell immunity and how this is modulated by regulatory cells, associated comorbidities and the host microbiome is discussed. We systematically map how different suppressive immune cell subsets may affect effector cell responses at the local site of infection. We also dissect how common co-morbidities such as HIV, helminthes and diabetes may bias protective TB immunity towards pathogenic and regulatory responses. Finally, also the composition and diversity of the microbiome in the lung and gut could affect host TB immunity. Understanding these various aspects of the immunological balance in the human host is fundamental to prevent TB infection and disease. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Mass amplifying probe for sensitive fluorescence anisotropy detection of small molecules in complex biological samples.

Science.gov (United States)

Cui, Liang; Zou, Yuan; Lin, Ninghang; Zhu, Zhi; Jenkins, Gareth; Yang, Chaoyong James

2012-07-03

Fluorescence anisotropy (FA) is a reliable and excellent choice for fluorescence sensing. One of the key factors influencing the FA value for any molecule is the molar mass of the molecule being measured. As a result, the FA method with functional nucleic acid aptamers has been limited to macromolecules such as proteins and is generally not applicable for the analysis of small molecules because their molecular masses are relatively too small to produce observable FA value changes. We report here a molecular mass amplifying strategy to construct anisotropy aptamer probes for small molecules. The probe is designed in such a way that only when a target molecule binds to the probe does it activate its binding ability to an anisotropy amplifier (a high molecular mass molecule such as protein), thus significantly increasing the molecular mass and FA value of the probe/target complex. Specifically, a mass amplifying probe (MAP) consists of a targeting aptamer domain against a target molecule and molecular mass amplifying aptamer domain for the amplifier protein. The probe is initially rendered inactive by a small blocking strand partially complementary to both target aptamer and amplifier protein aptamer so that the mass amplifying aptamer domain would not bind to the amplifier protein unless the probe has been activated by the target. In this way, we prepared two probes that constitute a target (ATP and cocaine respectively) aptamer, a thrombin (as the mass amplifier) aptamer, and a fluorophore. Both probes worked well against their corresponding small molecule targets, and the detection limits for ATP and cocaine were 0.5 μM and 0.8 μM, respectively. More importantly, because FA is less affected by environmental interferences, ATP in cell media and cocaine in urine were directly detected without any tedious sample pretreatment. Our results established that our molecular mass amplifying strategy can be used to design aptamer probes for rapid, sensitive, and selective

STAT3, a Key Parameter of Cytokine-driven Tissue Protection During Sterile Inflammation – the Case of Experimental Acetaminophen (Paracetamol-induced Liver Damage

Directory of Open Access Journals (Sweden)

Heiko eMühl

2016-05-01

Full Text Available Acetaminophen (APAP, N-acetyl-p-aminophenol, or paracetamol overdosing is a prevalent cause of acute liver injury. While clinical disease is initiated by overt parenchymal hepatocyte necrosis in response to the analgetic, course of intoxication is substantially influenced by associated activation of innate immunity. This process is supposed to be set in motion by release of danger associated molecular patterns (DAMPs from dying hepatocytes and is accompanied by an inflammatory cytokine response. Murine models of APAP-induced liver injury emphasize the complex role that DAMPs and cytokines play in promoting either hepatic pathogenesis or resolution and recovery from intoxication. Whereas the function of key inflammatory cytokines is controversially discussed, a subclass of specific cytokines capable of efficiently activating the hepatocyte signal transducer and activator of transcription (STAT-3 pathway stands out as being consistently protective in murine models of APAP intoxication. Those include foremost interleukin (IL-6, IL-11, IL-13, and IL-22. Above all, activation of STAT3 under the influence of these cytokines has the capability to drive hepatocyte compensatory proliferation, a key principle of the regenerating liver. Herein, the role of these specific cytokines during experimental APAP-induced liver injury is highlighted and discussed in a broader perspective. In hard-to-treat or at-risk patients standard therapy may fail and APAP intoxication can proceed towards a fatal condition. Focused administration of recombinant STAT3-activating cytokines may evolve as novel therapeutic approach under those ill-fated conditions.

Molecule of the Month

Indian Academy of Sciences (India)

Atoms in a molecule generally prefer, particularly among the neighbouring ones, certain optimmn geometrical relationships. These are manifested in specific ranges of bond lengths, bond angles, torsion angles etc. As it always happens, chemists are interested in making molecules where these 'standard relationships' are ...

Identification of the key bitter compounds in our daily diet is a prerequisite for the understanding of the hTAS2R gene polymorphisms affecting food choice.

Science.gov (United States)

Hofmann, Thomas

2009-07-01

In order to decode genetic variations affecting food choice and to determine whether to accept or to reject certain food products, it is a necessary prerequisite to deorphanize the hTAS2R/ligand pairs using the key bitter compounds in foods as stimuli rather than doing this either by using artificial molcules, to which the normal consumer had never been exposed, or by using food-born molecules which do not at all contribute to the overall bitterness. Therefore, the chemical structure of the most active bitter molecules in foods needs to be unequivocally determined in order to be sure that hTAS2R polymorphisms are related to the key molecules which really contribute to the overall bitterness perception of food products. As most studies focused primarily on quantitatively predominating compounds, rather than selecting the target compounds to be identified with regard to taste-activity, it seems that yet unknown components play a key role in evoking the bitter taste of food products. Driven by the need to discover the key players inducing the food taste, the research area "sensomics" made tremendous efforts in recent years to map the sensometabolome and to identify the most intense taste-active metabolites in fresh and processed foods. The present article summarizes recent studies on the identification of orphan key bitter stimuli in fresh, fermented, and thermally processed foods using carrots, cheese, and roasted coffee as examples.

Expression and Function of the Homeostatic Molecule Del-1 in Endothelial Cells and the Periodontal Tissue

Directory of Open Access Journals (Sweden)

Jieun Shin

2013-01-01

Full Text Available Developmental endothelial locus-1 (Del-1 is an endothelial cell-secreted protein that limits the recruitment of neutrophils by antagonizing the interaction between the LFA-1 integrin on neutrophils and the intercellular adhesion molecule (ICAM-1 on endothelial cells. Mice with genetic or age-associated Del-1 deficiency exhibit increased neutrophil infiltration in the periodontium resulting in inflammatory bone loss. Here we investigated additional novel mechanisms whereby Del-1 could interfere with neutrophil recruitment and inflammation. Treatment of human endothelial cells with Del-1 did not affect the expression of endothelial molecules involved in the leukocyte adhesion cascade (ICAM-1, VCAM-1, and E-selectin. Moreover, genetic or age-associated Del-1 deficiency did not significantly alter the expression of these adhesion molecules in the murine periodontium, further ruling out altered adhesion molecule expression as a mechanism whereby Del-1 regulates leukocyte recruitment. Strikingly, Del-1 inhibited ICAM-1-dependent chemokine release (CXCL2, CCL3 by neutrophils. Therefore, Del-1 could potentially suppress the amplification of inflammatory cell recruitment mediated through chemokine release by infiltrating neutrophils. Interestingly, Del-1 was itself regulated by inflammatory stimuli, which generally exerted opposite effects on adhesion molecule expression. The reciprocal regulation between Del-1 and inflammation may contribute to optimally balance the protective and the potentially harmful effects of inflammatory cell recruitment.

Dissociation and decay of ultracold sodium molecules

International Nuclear Information System (INIS)

Mukaiyama, T.; Abo-Shaeer, J.R.; Xu, K.; Chin, J.K.; Ketterle, W.

2004-01-01

The dissociation of ultracold molecules was studied by ramping an external magnetic field through a Feshbach resonance. The observed dissociation energies directly yielded the strength of the atom-molecule coupling. They showed nonlinear dependence on the ramp speed. This was explained by a Wigner threshold law which predicts that the decay rate of the molecules above threshold increases with the density of states. In addition, inelastic molecule-molecule and molecule-atom collisions were characterized

Protection of Facilities and Risk Assessment Application

OpenAIRE

Nađ, Ivan; Mihaljević, Branko; Mihalinčić, Martina

2014-01-01

The state of security on a specific area imposes the necessity for constant analysis of the existing system of protection of key state facilities, especially facilities of special significance for the defence. The facilities of special significance for the defence are an important part of the daily life, and enable smooth functioning of the economy and all other state activities. The protection of facilities of special significance for the defence is considered to be a system of obligatory me...

Single-Molecule Interfacial Electron Transfer

Energy Technology Data Exchange (ETDEWEB)

Lu, H. Peter [Bowling Green State Univ., Bowling Green, OH (United States). Dept. of Chemistry and Center for Photochemical Sciences

2017-11-28

This project is focused on the use of single-molecule high spatial and temporal resolved techniques to study molecular dynamics in condensed phase and at interfaces, especially, the complex reaction dynamics associated with electron and energy transfer rate processes. The complexity and inhomogeneity of the interfacial ET dynamics often present a major challenge for a molecular level comprehension of the intrinsically complex systems, which calls for both higher spatial and temporal resolutions at ultimate single-molecule and single-particle sensitivities. Combined single-molecule spectroscopy and electrochemical atomic force microscopy approaches are unique for heterogeneous and complex interfacial electron transfer systems because the static and dynamic inhomogeneities can be identified and characterized by studying one molecule at a specific nanoscale surface site at a time. The goal of our project is to integrate and apply these spectroscopic imaging and topographic scanning techniques to measure the energy flow and electron flow between molecules and substrate surfaces as a function of surface site geometry and molecular structure. We have been primarily focusing on studying interfacial electron transfer under ambient condition and electrolyte solution involving both single crystal and colloidal TiO₂ and related substrates. The resulting molecular level understanding of the fundamental interfacial electron transfer processes will be important for developing efficient light harvesting systems and broadly applicable to problems in fundamental chemistry and physics. We have made significant advancement on deciphering the underlying mechanism of the complex and inhomogeneous interfacial electron transfer dynamics in dyesensitized TiO₂ nanoparticle systems that strongly involves with and regulated by molecule-surface interactions. We have studied interfacial electron transfer on TiO₂ nanoparticle surfaces by using ultrafast single-molecule

Enrichment of megabase-sized DNA molecules for single-molecule optical mapping and next-generation sequencing

DEFF Research Database (Denmark)

Łopacińska-Jørgensen, Joanna M; Pedersen, Jonas Nyvold; Bak, Mads

2017-01-01

Next-generation sequencing (NGS) has caused a revolution, yet left a gap: long-range genetic information from native, non-amplified DNA fragments is unavailable. It might be obtained by optical mapping of megabase-sized DNA molecules. Frequently only a specific genomic region is of interest, so......-megabase- to megabase-sized DNA molecules were recovered from the gel and analysed by denaturation-renaturation optical mapping. Size-selected molecules from the same gel were sequenced by NGS. The optically mapped molecules and the NGS reads showed enrichment from regions defined by NotI restriction sites. We...... demonstrate that the unannotated genome can be characterized in a locus-specific manner via molecules partially overlapping with the annotated genome. The method is a promising tool for investigation of structural variants in enriched human genomic regions for both research and diagnostic purposes. Our...

Key-value store with internal key-value storage interface

Science.gov (United States)

Bent, John M.; Faibish, Sorin; Ting, Dennis P. J.; Tzelnic, Percy; Gupta, Uday; Grider, Gary; Bonnie, David J.

2018-01-16

A key-value store is provided having one or more key-value storage interfaces. A key-value store on at least one compute node comprises a memory for storing a plurality of key-value pairs; and an abstract storage interface comprising a software interface module that communicates with at least one persistent storage device providing a key-value interface for persistent storage of one or more of the plurality of key-value pairs, wherein the software interface module provides the one or more key-value pairs to the at least one persistent storage device in a key-value format. The abstract storage interface optionally processes one or more batch operations on the plurality of key-value pairs. A distributed embodiment for a partitioned key-value store is also provided.

Counteracting chemical chaperone effects on the single-molecule α-synuclein structural landscape.

Science.gov (United States)

Ferreon, Allan Chris M; Moosa, Mahdi Muhammad; Gambin, Yann; Deniz, Ashok A

2012-10-30

Protein structure and function depend on a close interplay between intrinsic folding energy landscapes and the chemistry of the protein environment. Osmolytes are small-molecule compounds that can act as chemical chaperones by altering the environment in a cellular context. Despite their importance, detailed studies on the role of these chemical chaperones in modulating structure and dimensions of intrinsically disordered proteins have been limited. Here, we used single-molecule Förster resonance energy transfer to test the counteraction hypothesis of counterbalancing effects between the protecting osmolyte trimethylamine-N-oxide (TMAO) and denaturing osmolyte urea for the case of α-synuclein, a Parkinson's disease-linked protein whose monomer exhibits significant disorder. The single-molecule experiments, which avoid complications from protein aggregation, do not exhibit clear solvent-induced cooperative protein transitions for these osmolytes, unlike results from previous studies on globular proteins. Our data demonstrate the ability of TMAO and urea to shift α-synuclein structures towards either more compact or expanded average dimensions. Strikingly, the experiments directly reveal that a 21 [urea][TMAO] ratio has a net neutral effect on the protein's dimensions, a result that holds regardless of the absolute osmolyte concentrations. Our findings shed light on a surprisingly simple aspect of the interplay between urea and TMAO on α-synuclein in the context of intrinsically disordered proteins, with potential implications for the biological roles of such chemical chaperones. The results also highlight the strengths of single-molecule experiments in directly probing the chemical physics of protein structure and disorder in more chemically complex environments.

Counteracting chemical chaperone effects on the single-molecule α-synuclein structural landscape

Science.gov (United States)

Ferreon, Allan Chris M.; Moosa, Mahdi Muhammad; Deniz, Ashok A.

2012-01-01

Protein structure and function depend on a close interplay between intrinsic folding energy landscapes and the chemistry of the protein environment. Osmolytes are small-molecule compounds that can act as chemical chaperones by altering the environment in a cellular context. Despite their importance, detailed studies on the role of these chemical chaperones in modulating structure and dimensions of intrinsically disordered proteins have been limited. Here, we used single-molecule Förster resonance energy transfer to test the counteraction hypothesis of counterbalancing effects between the protecting osmolyte trimethylamine-N-oxide (TMAO) and denaturing osmolyte urea for the case of α-synuclein, a Parkinson’s disease-linked protein whose monomer exhibits significant disorder. The single-molecule experiments, which avoid complications from protein aggregation, do not exhibit clear solvent-induced cooperative protein transitions for these osmolytes, unlike results from previous studies on globular proteins. Our data demonstrate the ability of TMAO and urea to shift α-synuclein structures towards either more compact or expanded average dimensions. Strikingly, the experiments directly reveal that a 2∶1 [urea]∶[TMAO] ratio has a net neutral effect on the protein’s dimensions, a result that holds regardless of the absolute osmolyte concentrations. Our findings shed light on a surprisingly simple aspect of the interplay between urea and TMAO on α-synuclein in the context of intrinsically disordered proteins, with potential implications for the biological roles of such chemical chaperones. The results also highlight the strengths of single-molecule experiments in directly probing the chemical physics of protein structure and disorder in more chemically complex environments. PMID:22826265

Preface: Special Topic on Single-Molecule Biophysics.

Science.gov (United States)

Makarov, Dmitrii E; Schuler, Benjamin

2018-03-28

Single-molecule measurements are now almost routinely used to study biological systems and processes. The scope of this special topic emphasizes the physics side of single-molecule observations, with the goal of highlighting new developments in physical techniques as well as conceptual insights that single-molecule measurements bring to biophysics. This issue also comprises recent advances in theoretical physical models of single-molecule phenomena, interpretation of single-molecule signals, and fundamental areas of statistical mechanics that are related to single-molecule observations. A particular goal is to illustrate the increasing synergy between theory, simulation, and experiment in single-molecule biophysics.

The role of the ion-molecule and molecule-molecule interactions in the formation of the two-ion average force interaction potential

CERN Document Server

Ajrian, E A; Sidorenko, S N

2002-01-01

The effect of the ion-molecule and intermolecular interactions on the formation of inter-ion average force potentials is investigated within the framework of a classical ion-dipole model of electrolyte solutions. These potentials are shown to possess the Coulomb asymptotics at large distances while in the region of mean distances they reveal creation and disintegration of solvent-shared ion pairs. The calculation results provide a qualitatively authentic physical picture which is experimentally observed in strong electrolytes solutions. In particular, an increased interaction between an ion and a molecule enhances formation of ion pairs in which the ions are separated by one solvent molecule

Labelled molecules, modern research implements

International Nuclear Information System (INIS)

Pichat, L.; Langourieux, Y.

1974-01-01

Details of the synthesis of carbon 14- and tritium-labelled molecules are examined. Although the methods used are those of classical organic chemistry the preparation of carbon 14-labelled molecules differs in some respects, most noticeably in the use of 14 CO 2 which requires very special handling techniques. For the tritium labelling of organic molecules the methods are somewhat different, very often involving exchange reactions. The following are described in turn: the so-called Wilzbach exchange method; exchange by catalysis in solution; catalytic hydrogenation with tritium; reductions with borotritides. Some applications of labelled molecules in organic chemistry, biochemistry and pharmacology are listed [fr

Special Issue: “Molecules against Alzheimer”

Directory of Open Access Journals (Sweden)

Michael Decker

2016-12-01

Full Text Available This Special Issue, entitled “Molecules against Alzheimer”, gathers a number of original articles, short communications, and review articles on recent research efforts toward the development of novel drug candidates, diagnostic agents and therapeutic approaches for Alzheimer’s disease (AD, the most prevalent neurodegenerative disorder and a leading cause of death worldwide. This Special Issue contains many interesting examples describing the design, synthesis, and pharmacological profiling of novel compounds that hit one or several key biological targets, such as cholinesterases, β-amyloid formation or aggregation, monoamine oxidase B, oxidative stress, biometal dyshomeostasis, mitochondrial dysfunction, serotonin and/or melatonin systems, the Wnt/β-catenin pathway, sigma receptors, nicotinamide phosphoribosyltransferase, or nuclear erythroid 2-related factor. The development of novel AD diagnostic agents based on tau protein imaging and the use of lithium or intranasal insulin for the prevention or the symptomatic treatment of AD is also covered in some articles of the Special Issue.

Hybrid molecule/superconductor assemblies

International Nuclear Information System (INIS)

McDevitt, J.T.; Haupt, S.G.; Riley, D.R.; Zhao, J.; Zhou, J.P., Jones, C.

1993-01-01

The fabrication of electronic devices from molecular materials has attracted much attention recently. Schottky diodes, molecular transistors, metal-insulator-semiconductor diodes, MIS field effect transistors and light emitting diodes have all been prepared utilizing such substances. The active elements in these devices have been constructed by depositing the molecular phase onto the surface of a metal, semiconductor or insulating substrate. With the recent discovery of high temperature superconductivity, new opportunities now exist for the study of molecule/superconductor interactions as well as for the construction of novel hybrid molecule/superconductor devices. In this paper, methods for preparing the initial two composite molecule/semiconductor devices will be reported. Consequently, light sensors based on dye-coated superconductor junctions as well as molecular switches fashioned from conductive polymer coated superconductor junctions as well as molecular switches fashioned from conductive polymer coated superconductor microbridges will be discussed. Moreover, molecule/superconductor energy and electron transfer phenomena will be illustrated also for the first time

Uniform Protection for Multi-exposed Targets

DEFF Research Database (Denmark)

Vigo, Roberto; Nielson, Flemming; Nielson, Hanne Riis

2014-01-01

the Quality Calculus that computes the combinations of data required to reach a program point and relates them to a notion of cost. In this way, we can compare the security deployed on different paths that expose the same resource. The analysis is formalised in terms of flow logic, and is implemented......Ensuring that information is protected proportionately to its value is a major challenge in the development of robust distributed systems, where code complexity and technological constraints might allow reaching a key functionality along various paths. We propose a protection analysis over...

Key policy choices in groundwater quality management

International Nuclear Information System (INIS)

Batie, S.S.; Diebel, P.L.

1990-01-01

The fundamental policy choice of who has the right to do what to whom is a pivotal issue of governance. Over the last few decades, the answer to that question has become more restrictive to those who own and use natural resources as inputs into production processes. Increasingly, the beneficiaries of new policy initiatives are those who desire higher protection of groundwater quality. With respect to groundwater management, policy design increasingly reflects such diverse interests as agriculturists, industrialists, homeowners, local government officials and state officials. Policy design is becoming complex, in part because of this diversity and in part because scientific uncertainty hampers informed policy design. No umbrella federal legislation exists for managing groundwater resources. EPA's role has been mainly an advisory one on groundwater issues. The difficulties and responsibilities of protecting groundwater thus remain with the states. For the near future, it is the states that will address key policy choices with respect to groundwater quality management issues

Liver lipid molecules induce PEPCK-C gene transcription and attenuate insulin action

International Nuclear Information System (INIS)

Chen Guoxun

2007-01-01

Cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) plays key roles in gluconeogenesis, glyceroneogenesis, and cataplerosis. Experiments were designed to examine the effects of endogenous lipid molecules from rat livers on the expression of PEPCK-C gene in primary rat hepatocytes. The lipid extracts prepared from livers of Zucker fatty, lean, and Wistar rats induced the expression levels of PEPCK-C transcripts. Insulin-mediated reduction of PEPCK-C gene expression was attenuated by the same treatment. The lipid extracts induced the relative luciferase activity of reporter gene constructs that contain a 2.2-kb 5' promoter fragment of PEPCK-C gene, but not the construct that contains only the 3' untranslated region (UTR) of its mRNA. The estimated half life of PEPCK-C transcripts in the presence of the lipid extract is the same as that in the absence of it. My results demonstrate for the first time that endogenous lipid molecules induce PEPCK-C gene transcription and attenuate insulin action in liver

Single-molecule conductivity of non-redox and redox molecules at pure and gold-mined Au(111)-electrode surfaces

DEFF Research Database (Denmark)

Zhang, Jingdong; Chi, Qijin; Ulstrup, Jens

The structure, two-dimensional organization, and function of molecules immobilized on solid surfaces can be addressed in a degree of detail that has reached the level of the single-molecule. In this context redox molecules are “smart” molecules adding sophisticated electronic function. Redox meta...

Using Future Value Analysis to Select an Optimal Portfolio of Force Protection Initiatives

National Research Council Canada - National Science Library

Eskridge, Robert

2003-01-01

With the recent increase in terrorist activity, force protection has become a key issue for the Department of Defense, Leading the research for new ideas and concepts in force protection for the US...

KEY FACTORS IN MARKETING FOCUSED SERVICES BUSINESSES

Directory of Open Access Journals (Sweden)

Doris Yohanna Martínez Castrillón

2016-07-01

Full Text Available This article aims to identify the key success factors in the marketing area and describe them as managerial allies for companies that wish to position themselves in the market under a good sustainable performance , for it has been consulted theoretical references of Marketing as a management partner with collection and integration of data. Methodologically, it is located within the type of descriptive research field, with a design of transactional non-experimental, with an intentional non-probabilistic stratified sample of four reporting units. The findings established fifteen (15 points of influence called "key success factors (FCE in the area of marketing, and managerial allies of service companies in the security, surveillance and protection sector in industrial, commercial and residential sectors. Finally, it is intended that the actions of marketing service companies should focus to the welfare of both the organization, such as users, both in the environment, and economic, social and technological, characterized by ethics, sustainable development and transparency to respond appropriately.

Federal Republic of Nigeria Diagnostic Review of Financial Consumer Protection : Key Findings and Recommendations

OpenAIRE

World Bank Group

2017-01-01

While only 44 percent of adults in Nigeria have an account at a formal financial institution, and only 2.5 percent have a mobile account, there are rapid innovations in both traditional and digital financial services that promote financial inclusion but also add complexity and risks for inexperienced consumers. Strengthening financial consumer protection (FCP) in Nigeria is therefore criti...

The origin of small and large molecule behavior in the vibrational relaxation of highly excited molecules

International Nuclear Information System (INIS)

Gordon, R.J.

1990-01-01

An explanation is proposed for the qualitatively different types of behavior that have been reported for the vibrational relaxation of highly excited diatomic and polyatomic molecules. It is argued that all of the diatomic molecules that have been studied in bulk relax adiabatically at room temperature. In contrast, large polyatomic molecules have low frequency modes which act at ''doorway'' modes for the rest of the molecules, producing an impulsive relaxation mechanism. The theoretical work of Nesbitt and Hynes showed that impulsive collisions result in an exponential decay of the average vibrational energy of a Morse oscillator, whereas adiabatic collisions produce nonexponential power law behavior. We propose that this result explains a large body of data for the vibrational relaxation of small and large molecules

A study of how precursor key concepts for organic chemistry success are understood by general chemistry students

Science.gov (United States)

Meyer, Patrick Gerard

This study examines college student understanding of key concepts that will support future organic chemistry success as determined by university instructors. During four one-hour individual interviews the sixteen subjects attempted to solve general chemistry problems. A think-aloud protocol was used along with a whiteboard where the students could draw and illustrate their ideas. The protocols for the interviews were adapted from the Covalent Structure and Bonding two-tiered multiple choice diagnostic instrument (Peterson, Treagust, & Garnett, 1989) and augmented by the Geometry and Polarity of Molecules single-tiered multiple choice instrument (Furio & Calatayud, 1996). The interviews were videotaped, transcribed, and coded for analysis to determine the subjects' understanding of the key ideas. The subjects displayed many misconceptions that were summarized into nine assertions about student conceptualization of chemistry. (1) Many students misunderstand the location and nature of intermolecular forces. (2) Some think electronegativity differences among atoms in a molecule are sufficient to make the molecule polar, regardless of spatial arrangement. (3) Most know that higher phase change temperatures imply stronger intermolecular attractions, but many do not understand the difference between covalent molecular and covalent network substances. (4) Many have difficulty deciding whether a molecule is polar or non-polar, often confusing bilateral symmetry with spatial symmetry in all three dimensions. (5) Many cannot reliably draw correct Lewis structures due to carelessness and overuse of flawed algorithms. (6) Many are confused by how electrons can both repel one other and facilitate bonding between atoms via orbitals---this seems oxymoronic to them. (7) Many cannot explain why the atoms of certain elements do not follow the octet rule and some believe the octet rule alone can determine the shape of a molecule. (8) Most do know that electronegativity and polarity

Anticollusion Attack Noninteractive Security Hierarchical Key Agreement Scheme in WHMS

Directory of Open Access Journals (Sweden)

Kefei Mao

2016-01-01

Full Text Available Wireless Health Monitoring Systems (WHMS have potential to change the way of health care and bring numbers of benefits to patients, physicians, hospitals, and society. However, there are crucial barriers not only to transmit the biometric information but also to protect the privacy and security of the patients’ information. The key agreement between two entities is an essential cryptography operation to clear the barriers. In particular, the noninteractive hierarchical key agreement scheme becomes an attractive direction in WHMS because each sensor node or gateway has limited resources and power. Recently, a noninteractive hierarchical key agreement scheme has been proposed by Kim for WHMS. However, we show that Kim’s cryptographic scheme is vulnerable to the collusion attack if the physicians can be corrupted. Obviously, it is a more practical security condition. Therefore, we proposed an improved key agreement scheme against the attack. Security proof, security analysis, and experimental results demonstrate that our proposed scheme gains enhanced security and more efficiency than Kim’s previous scheme while inheriting its qualities of one-round communication and security properties.

Identifying Regional Key Eco-Space to Maintain Ecological Security Using GIS

Directory of Open Access Journals (Sweden)

Hualin Xie

2014-02-01

Full Text Available Ecological security and environmental sustainability are the foundations of sustainable development. With the acceleration of urbanization, increasing human activities have promoted greater impacts on the eco-spaces that maintain ecological security. Regional key eco-space has become the primary need to maintain environmental sustainability and can offer society with continued ecosystem services. In this paper, considering the security of water resources, biodiversity conservation, disaster avoidance and protection and natural recreation, an integrated index of eco-space importance was established and a method for identifying key eco-space was created using GIS, with Lanzhou City, China as a case study. The results show that the area of core eco-space in the Lanzhou City is approximately 50,908.7 hm2, accounting for 40% of the region’s total area. These areas mainly consist of geological hazard protection zones and the core zones of regional river systems, wetlands, nature reserves, forest parks and scenic spots. The results of this study provide some guidance for the management of ecological security, ecological restoration and environmental sustainability.

Atomistic theory of excitonic fine structure in InAs/InP nanowire quantum dot molecules

Science.gov (United States)

Świderski, M.; Zieliński, M.

2017-03-01

Nanowire quantum dots have peculiar electronic and optical properties. In this work we use atomistic tight binding to study excitonic spectra of artificial molecules formed by a double nanowire quantum dot. We demonstrate a key role of atomistic symmetry and nanowire substrate orientation rather than cylindrical shape symmetry of a nanowire and a molecule. In particular for [001 ] nanowire orientation we observe a nonvanishing bright exciton splitting for a quasimolecule formed by two cylindrical quantum dots of different heights. This effect is due to interdot coupling that effectively reduces the overall symmetry, whereas single uncoupled [001 ] quantum dots have zero fine structure splitting. We found that the same double quantum dot system grown on [111 ] nanowire reveals no excitonic fine structure for all considered quantum dot distances and individual quantum dot heights. Further we demonstrate a pronounced, by several orders of magnitude, increase of the dark exciton optical activity in a quantum dot molecule as compared to a single quantum dot. For [111 ] systems we also show spontaneous localization of single particle states in one of nominally identical quantum dots forming a molecule, which is mediated by strain and origins from the lack of the vertical inversion symmetry in [111 ] nanostructures of overall C3 v symmetry. Finally, we study lowering of symmetry due to alloy randomness that triggers nonzero excitonic fine structure and the dark exciton optical activity in realistic nanowire quantum dot molecules of intermixed composition.

Privacy rules for DNA databanks. Protecting coded 'future diaries'.

Science.gov (United States)

Annas, G J

1993-11-17

In privacy terms, genetic information is like medical information. But the information contained in the DNA molecule itself is more sensitive because it contains an individual's probabilistic "future diary," is written in a code that has only partially been broken, and contains information about an individual's parents, siblings, and children. Current rules for protecting the privacy of medical information cannot protect either genetic information or identifiable DNA samples stored in DNA databanks. A review of the legal and public policy rationales for protecting genetic privacy suggests that specific enforceable privacy rules for DNA databanks are needed. Four preliminary rules are proposed to govern the creation of DNA databanks, the collection of DNA samples for storage, limits on the use of information derived from the samples, and continuing obligations to those whose DNA samples are in the databanks.

Specific Kv1.3 blockade modulates key cholesterol-metabolism-associated molecules in human macrophages exposed to ox-LDL[S

Science.gov (United States)

Yang, Yong; Wang, Yan-Fu; Yang, Xiao-Fang; Wang, Zhao-Hui; Lian, Yi-Tian; Yang, Ying; Li, Xiao-Wei; Gao, Xiang; Chen, Jian; Shu, Yan-Wen; Cheng, Long-Xian; Liao, Yu-Hua; Liu, Kun

2013-01-01

Cholesterol-metabolism-associated molecules, including scavenger receptor class A (SR-A), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), CD36, ACAT1, ABCA1, ABCG1, and scavenger receptor class B type I, can modulate cholesterol metabolism in the transformation from macrophages to foam cells. Voltage-gated potassium channel Kv1.3 has increasingly been demonstrated to play an important role in the modulation of macrophage function. Here, we investigate the role of Kv1.3 in modulating cholesterol-metabolism-associated molecules in human acute monocytic leukemia cell-derived macrophages (THP-1 macrophages) and human monocyte-derived macrophages exposed to oxidized LDL (ox-LDL). Human Kv1.3 and Kv1.5 channels (hKv1.3 and hKv1.5) are expressed in macrophages and form a heteromultimeric channel. The hKv1.3-E314 antibody that we had generated as a specific hKv1.3 blocker inhibited outward delayed rectifier potassium currents, whereas the hKv1.5-E313 antibody that we had generated as a specific hKv1.5 blocker failed. Accordingly, the hKv1.3-E314 antibody reduced percentage of cholesterol ester and enhanced apoA-I-mediated cholesterol efflux in THP-1 macrophages and human monocyte-derived macrophages exposed to ox-LDL. The hKv1.3-E314 antibody downregulated SR-A, LOX-1, and ACAT1 expression and upregulated ABCA1 expression in THP-1 macrophages and human monocyte-derived macrophages. Our results reveal that specific Kv1.3 blockade represents a novel strategy modulating cholesterol metabolism in macrophages, which benefits the treatment of atherosclerotic lesions. PMID:23099443

Twistacene contained molecule for optical nonlinearity: Excited-state based negative refraction and optical limiting

Science.gov (United States)

Wu, Xingzhi; Xiao, Jinchong; Sun, Ru; Jia, Jidong; Yang, Junyi; Ao, Guanghong; Shi, Guang; Wang, Yuxiao; Zhang, Xueru; Song, Yinglin

2018-06-01

Spindle-type molecules containing twisted acenes (PyBTA-1 &PyBTA-2) are designed, synthesized characterized. Picosecond Z-scan experiments under 532 nm show reverse saturable absorption and negative nonlinear refraction, indicating large third-order optical nonlinearity in PyBTA-1. The mechanism of the optical nonlinearity is investigated and the results show that the nonlinear absorption and refraction in PyBTA-1 originates from a charge transfer (CT) state. Furthermore, relatively long lifetime and absorptive cross section of the CT state are measured. Based on the excited state absorption in PyBTA-1, strong optical limiting with ∼0.3 J/cm2 thresholds are obtained when excited by picoseconds and nanoseconds pulses. The findings on nonlinear optics suggest PyBTA-1 a promising material of all optical modulation and laser protection, which enrich the potential applications of these spindle-type molecules. Comparing to the previously reported spindle-type molecules with analogous structures, the introduction of ICT in PyBTA-1 &PyBTA-2 dramatically decreases the two-photon absorption while enhances the nonlinear refraction. The results could be used to selectively tailor the optical nonlinearity in such kind of compounds.

Critical Infrastructure Protection- Los Alamos National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Bofman, Ryan K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-02-24

Los Alamos National Laboratory (LANL) has been a key facet of Critical National Infrastructure since the nuclear bombing of Hiroshima exposed the nature of the Laboratory’s work in 1945. Common knowledge of the nature of sensitive information contained here presents a necessity to protect this critical infrastructure as a matter of national security. This protection occurs in multiple forms beginning with physical security, followed by cybersecurity, safeguarding of classified information, and concluded by the missions of the National Nuclear Security Administration.

Integrating large-scale data and RNA technology to protect crops from fungal pathogens

Directory of Open Access Journals (Sweden)

Ian Joseph Girard

2016-05-01

Full Text Available With a rapidly growing human population it is expected that plant science researchers and the agricultural community will need to increase food productivity using less arable land. This challenge is complicated by fungal pathogens and diseases, many of which can severely impact crop yield. Current measures to control fungal pathogens are either ineffective or have adverse effects on the agricultural enterprise. Thus, developing new strategies through research innovation to protect plants from pathogenic fungi is necessary to overcome these hurdles. RNA sequencing technologies are increasing our understanding of the underlying genes and gene regulatory networks mediating disease outcomes. The application of invigorating next generation sequencing strategies to study plant-pathogen interactions has and will provide unprecedented insight into the complex patterns of gene activity responsible for crop protection. However, questions remain about how biological processes in both the pathogen and the host are specified in space directly at the site of infection and over the infection period. The integration of cutting edge molecular and computational tools will provide plant scientists with the arsenal required to identify genes and molecules that play a role in plant protection. Large scale RNA sequence data can then be used to protect plants by targeting genes essential for pathogen viability in the production of stably transformed lines expressing RNA interference molecules, or through foliar applications of double stranded RNA.

Ultraviolet/visible and Fourier transform infrared spectroscopic investigations of organic–inorganic hybrid layers for UV protection

Energy Technology Data Exchange (ETDEWEB)

Präfke, Christiane, E-mail: christiane.praefke@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena (Germany); Schulz, Ulrike, E-mail: ulrike.schulz@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Kaiser, Norbert, E-mail: norbert.kaiser@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Tünnermann, Andreas, E-mail: andreas.tuennermann@iof.fraunhofer.de [Fraunhofer Institute of Applied Optics and Precision Engineering, Optical Coatings Department, Albert-Einstein-Straße 7, 07745 Jena (Germany); Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena (Germany)

2013-04-01

A study of vacuum-deposited organic–inorganic hybrid coatings for ultraviolet (UV) protection of polycarbonate is presented. For this purpose, UV-absorbing organic molecules were embedded in a silica matrix by thermal co-evaporation. Typical UV absorbers, namely a benzotriazole, a hydroxyphenyltriazine, and a cyanoacrylate, were used as organic materials. The hybrid layers were investigated by means of ultraviolet/visible (UV/VIS) and Fourier transform infrared spectroscopy (FTIR) concerning their UV/VIS absorption properties and the influence of the silica network on the organic molecules. The porosity and silica–organic interactions are discussed with reference to the infrared spectra. UV irradiation experiments were carried out to demonstrate the UV protection ability of the hybrid layers. Hybrid layers containing the hydroxyphenyltriazine compound showed the best results. - Highlights: ► Vacuum deposited organic–inorganic UV protective coatings for polycarbonate ► Thermal co-evaporation of organic UV absorbing compounds with silica ► Matrix materials and the absorber concentration influence the absorption behavior. ► The coatings on PC show improved UV stability under artificial irradiation. ► The hydroxyphenyltriazine–silica layer shows best UV protection results.

Freshness-Preserving Non-Interactive Hierarchical Key Agreement Protocol over WHMS

Directory of Open Access Journals (Sweden)

Hyunsung Kim

2014-12-01

Full Text Available The digitization of patient health information (PHI for wireless health monitoring systems (WHMSs has brought many benefits and challenges for both patients and physicians. However, security, privacy and robustness have remained important challenges for WHMSs. Since the patient’s PHI is sensitive and the communication channel, i.e., the Internet, is insecure, it is important to protect them against unauthorized entities, i.e., attackers. Otherwise, failure to do so will not only lead to the compromise of a patient’s privacy, but will also put his/her life at risk. This paper proposes a freshness-preserving non-interactive hierarchical key agreement protocol (FNKAP for WHMSs. The FNKAP is based on the concept of the non-interactive identity-based key agreement for communication efficiency. It achieves patient anonymity between a patient and physician, session key secrecy and resistance against various security attacks, especially including replay attacks.

Freshness-Preserving Non-Interactive Hierarchical Key Agreement Protocol over WHMS

Science.gov (United States)

Kim, Hyunsung

2014-01-01

The digitization of patient health information (PHI) for wireless health monitoring systems (WHMSs) has brought many benefits and challenges for both patients and physicians. However, security, privacy and robustness have remained important challenges for WHMSs. Since the patient's PHI is sensitive and the communication channel, i.e., the Internet, is insecure, it is important to protect them against unauthorized entities, i.e., attackers. Otherwise, failure to do so will not only lead to the compromise of a patient's privacy, but will also put his/her life at risk. This paper proposes a freshness-preserving non-interactive hierarchical key agreement protocol (FNKAP) for WHMSs. The FNKAP is based on the concept of the non-interactive identity-based key agreement for communication efficiency. It achieves patient anonymity between a patient and physician, session key secrecy and resistance against various security attacks, especially including replay attacks. PMID:25513824

Molecule of the Month

Indian Academy of Sciences (India)

Cyclo bu tadiene (1) has been one of the most popular molecules for experimentalists and theoreticians. This molecule is unstable as . it is antiaromatic ( 4,n electrons in a cyclic array). Even though some highly substituted cyclobutadienes, for example, compound 2 and the Fe(CO)3 complex of cyclobutadiene (3) are ...

Single-molecule techniques in biophysics: a review of the progress in methods and applications

Science.gov (United States)

Miller, Helen; Zhou, Zhaokun; Shepherd, Jack; Wollman, Adam J. M.; Leake, Mark C.

2018-02-01

Single-molecule biophysics has transformed our understanding of biology, but also of the physics of life. More exotic than simple soft matter, biomatter lives far from thermal equilibrium, covering multiple lengths from the nanoscale of single molecules to up to several orders of magnitude higher in cells, tissues and organisms. Biomolecules are often characterized by underlying instability: multiple metastable free energy states exist, separated by levels of just a few multiples of the thermal energy scale k B T, where k B is the Boltzmann constant and T absolute temperature, implying complex inter-conversion kinetics in the relatively hot, wet environment of active biological matter. A key benefit of single-molecule biophysics techniques is their ability to probe heterogeneity of free energy states across a molecular population, too challenging in general for conventional ensemble average approaches. Parallel developments in experimental and computational techniques have catalysed the birth of multiplexed, correlative techniques to tackle previously intractable biological questions. Experimentally, progress has been driven by improvements in sensitivity and speed of detectors, and the stability and efficiency of light sources, probes and microfluidics. We discuss the motivation and requirements for these recent experiments, including the underpinning mathematics. These methods are broadly divided into tools which detect molecules and those which manipulate them. For the former we discuss the progress of super-resolution microscopy, transformative for addressing many longstanding questions in the life sciences, and for the latter we include progress in ‘force spectroscopy’ techniques that mechanically perturb molecules. We also consider in silico progress of single-molecule computational physics, and how simulation and experimentation may be drawn together to give a more complete understanding. Increasingly, combinatorial techniques are now used, including

Regulation of metabolic networks by small molecule metabolites

Directory of Open Access Journals (Sweden)

Kanehisa Minoru

2007-03-01

Full Text Available Abstract Background The ability to regulate metabolism is a fundamental process in living systems. We present an analysis of one of the mechanisms by which metabolic regulation occurs: enzyme inhibition and activation by small molecules. We look at the network properties of this regulatory system and the relationship between the chemical properties of regulatory molecules. Results We find that many features of the regulatory network, such as the degree and clustering coefficient, closely match those of the underlying metabolic network. While these global features are conserved across several organisms, we do find local differences between regulation in E. coli and H. sapiens which reflect their different lifestyles. Chemical structure appears to play an important role in determining a compounds suitability for use in regulation. Chemical structure also often determines how groups of similar compounds can regulate sets of enzymes. These groups of compounds and the enzymes they regulate form modules that mirror the modules and pathways of the underlying metabolic network. We also show how knowledge of chemical structure and regulation could be used to predict regulatory interactions for drugs. Conclusion The metabolic regulatory network shares many of the global properties of the metabolic network, but often varies at the level of individual compounds. Chemical structure is a key determinant in deciding how a compound is used in regulation and for defining modules within the regulatory system.

Spectroscopy and Chemistry of Cold Molecules

Science.gov (United States)

Momose, Takamasa

2012-06-01

Molecules at low temperatures are expected to behave quite differently from those at high temperatures because pronounced quantum effects emerge from thermal averages. Even at 10 K, a significant enhancement of reaction cross section is expected due to tunneling and resonance effects. Chemistry at this temperature is very important in order to understand chemical reactions in interstellar molecular clouds. At temperatures lower than 1 K, collisions and intermolecular interactions become qualitatively different from those at high temperatures because of the large thermal de Broglie wavelength of molecules. Collisions at these temperatures must be treated as the interference of molecular matter waves, but not as hard sphere collisions. A Bose-Einstein condensate is a significant state of matter as a result of coherent matter wave interaction. Especially, dense para-H_2 molecules are predicted to become a condensate even around 1 K. A convenient method to investigate molecules around 1 K is to dope molecules in cold matrices. Among various matrices, quantum hosts such as solid para-H_2 and superfluid He nano-droplets have been proven to be an excellent host for high-resolution spectroscopy. Rovibrational motion of molecules in these quantum hosts is well quantized on account of the weak interactions and the softness of quantum environment. The linewidths of infrared spectra of molecules in the quantum hosts are extremely narrow compared with those in other matrices. The sharp linewidths allow us to resolve fine spectral structures originated in subtle interactions between guest and host molecules. In this talk, I will describe how the splitting and lineshape of high-resolution spectra of molecules in quantum hosts give us new information on the static and dynamical interactions of molecules in quantum medium. The topics include dynamical response of superfluid environment upon rotational excitation, and possible superfluid phase of para-H_2 clusters. I will also

Histopathological and in vivo evidence of regucalcin as a protective molecule in mammary gland carcinogenesis

Energy Technology Data Exchange (ETDEWEB)

Marques, Ricardo; Vaz, Cátia V.; Maia, Cláudio J. [CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Gomes, Madalena [IPATIMUP, Institute of Molecular Pathology and Immunology, University of Porto, Porto (Portugal); Gama, Adelina [Department of Veterinary Sciences, Animal and Veterinary Science Research Center (CECAV), University of Trás-os-Montes and Alto Douro (UTAD) (Portugal); Alves, Gilberto; Santos, Cecília R. [CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal); Schmitt, Fernando [IPATIMUP, Institute of Molecular Pathology and Immunology, University of Porto, Porto (Portugal); Medical Faculty, University of Porto, Porto (Portugal); Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto (Canada); Department of Pathology, University Health Network, Toronto (Canada); Socorro, Sílvia, E-mail: ssocorro@fcsaude.ubi.pt [CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã (Portugal)

2015-01-15

Regucalcin (RGN) is a calcium-binding protein, which has been shown to be underexpressed in cancer cases. This study aimed to determine the association of RGN expression with clinicopathological parameters of human breast cancer. In addition, the role of RGN in malignancy of mammary gland using transgenic rats overexpressing the protein (Tg-RGN) was investigated. Wild-type (Wt) and Tg-RGN rats were treated with 7,12-dimethylbenz[α]anthracene (DMBA). Carcinogen-induced tumors were histologically classified and the Ki67 proliferation index was estimated. Immunohistochemistry analysis showed that RGN immunoreactivity was negatively correlated with the histological grade of breast infiltrating ductal carcinoma suggesting that progression of breast cancer is associated with loss of RGN. Tg-RGN rats displayed lower incidence of carcinogen-induced mammary gland tumors, as well as lower incidence of invasive forms. Moreover, higher proliferation was observed in non-invasive tumors of Wt animals comparatively with Tg-RGN. Overexpression of RGN was associated with diminished expression of cell-cycle inhibitors and increased expression of apoptosis inducers. Augmented activity of apoptosis effector caspase-3 was found in the mammary gland of Tg-RGN. RGN overexpression protected from carcinogen-induced mammary gland tumor development and was linked with reduced proliferation and increased apoptosis. These findings indicated the protective role of RGN in the carcinogenesis of mammary gland. - Highlights: • RGN immunoreactivity was negatively correlated with breast cancer differentiation. • Transgenic overexpression of RGN diminished incidence of carcinogen-induced tumors. • Transgenic overexpression of RGN restricted proliferation and fostered apoptosis. • RGN has a protective role in the carcinogenesis of mammary gland.

The CO-releasing molecule CORM-3 protects against articular degradation in the K/BxN serum transfer arthritis model.

NARCIS (Netherlands)

Maicas, N.; Ferrandiz, M.L.; Devesa, I.; Motterlini, R.; Koenders, M.I.; Berg, W.B. van den; Alcaraz, M.J.

2010-01-01

Carbon monoxide-releasing molecules can counteract inflammatory responses. The aim of this study was to investigate whether tricarbonylchloro(glycinate)ruthenium (II) (CORM-3) is able to control the effector phase of experimental arthritis. Arthritis was induced in C57Black-6 mice by an

Isotope separation using vibrationally excited molecules

International Nuclear Information System (INIS)

Woodroffe, J.A.; Keck, J.C.

1977-01-01

A system for isotope separation or enrichment wherein molecules of a selected isotope type in a flow of molecules of plural isotope types are vibrationally excited and collided with a background gas to provide enhanced diffusivity for the molecules of the selected isotope type permitting their separate collection. The system typically is for the enrichment of uranium using a uranium hexafluoride gas in combination with a noble gas such as argon. The uranium hexafluoride molecules having a specific isotope of uranium are vibrationally excited by laser radiation. The vibrational energy is converted to a translation energy upon collision with a particle of the background gas and the added translation energy enhances the diffusivity of the selected hexafluoride molecules facilitating its condensation on collection surfaces provided for that purpose. This process is periodically interrupted and the cryogenic flow halted to permit evaporation of the collected molecules to provide a distinct, enriched flow

Is an ecosystem services-based approach developed for setting specific protection goals for plant protection products applicable to other chemicals?

Science.gov (United States)

Maltby, Lorraine; Jackson, Mathew; Whale, Graham; Brown, A Ross; Hamer, Mick; Solga, Andreas; Kabouw, Patrick; Woods, Richard; Marshall, Stuart

2017-02-15

Clearly defined protection goals specifying what to protect, where and when, are required for designing scientifically sound risk assessments and effective risk management of chemicals. Environmental protection goals specified in EU legislation are defined in general terms, resulting in uncertainty in how to achieve them. In 2010, the European Food Safety Authority (EFSA) published a framework to identify more specific protection goals based on ecosystem services potentially affected by plant protection products. But how applicable is this framework to chemicals with different emission scenarios and receptor ecosystems? Four case studies used to address this question were: (i) oil refinery waste water exposure in estuarine environments; (ii) oil dispersant exposure in aquatic environments; (iii) down the drain chemicals exposure in a wide range of ecosystems (terrestrial and aquatic); (iv) persistent organic pollutant exposure in remote (pristine) Arctic environments. A four-step process was followed to identify ecosystems and services potentially impacted by chemical emissions and to define specific protection goals. Case studies demonstrated that, in principle, the ecosystem services concept and the EFSA framework can be applied to derive specific protection goals for a broad range of chemical exposure scenarios. By identifying key habitats and ecosystem services of concern, the approach offers the potential for greater spatial and temporal resolution, together with increased environmental relevance, in chemical risk assessments. With modifications including improved clarity on terminology/definitions and further development/refinement of the key concepts, we believe the principles of the EFSA framework could provide a methodical approach to the identification and prioritization of ecosystems, ecosystem services and the service providing units that are most at risk from chemical exposure. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights

A single molecule assay to probe monovalent and multivalent bonds between hyaluronan and its key leukocyte receptor CD44 under force

Science.gov (United States)

Bano, Fouzia; Banerji, Suneale; Howarth, Mark; Jackson, David G.; Richter, Ralf P.

2016-09-01

Glycosaminoglycans (GAGs), a category of linear, anionic polysaccharides, are ubiquitous in the extracellular space, and important extrinsic regulators of cell function. Despite the recognized significance of mechanical stimuli in cellular communication, however, only few single molecule methods are currently available to study how monovalent and multivalent GAG·protein bonds respond to directed mechanical forces. Here, we have devised such a method, by combining purpose-designed surfaces that afford immobilization of GAGs and receptors at controlled nanoscale organizations with single molecule force spectroscopy (SMFS). We apply the method to study the interaction of the GAG polymer hyaluronan (HA) with CD44, its receptor in vascular endothelium. Individual bonds between HA and CD44 are remarkably resistant to rupture under force in comparison to their low binding affinity. Multiple bonds along a single HA chain rupture sequentially and independently under load. We also demonstrate how strong non-covalent bonds, which are versatile for controlled protein and GAG immobilization, can be effectively used as molecular anchors in SMFS. We thus establish a versatile method for analyzing the nanomechanics of GAG·protein interactions at the level of single GAG chains, which provides new molecular-level insight into the role of mechanical forces in the assembly and function of GAG-rich extracellular matrices.

Pathways for Small Molecule Delivery to the Central Nervous System Across the Blood-Brain Barrier

OpenAIRE

Mikitsh, John L; Chacko, Ann-Marie

2014-01-01

The treatment of central nervous system (CNS) disease has long been difficult due to the ineffectiveness of drug delivery across the blood-brain barrier (BBB). This review summarizes important concepts of the BBB in normal versus pathophysiology and how this physical, enzymatic, and efflux barrier provides necessary protection to the CNS during drug delivery, and consequently treatment challenging. Small molecules account for the vast majority of available CNS drugs primarily due to their abi...

Countering resistance to protected-area extension.

Science.gov (United States)

Lindenmayer, David; Thorn, Simon; Noss, Reed

2018-04-01

The establishment of protected areas is a critical strategy for conserving biodiversity. Key policy directives like the Aichi targets seek to expand protected areas to 17% of Earth's land surface, with calls by some conservation biologists for much more. However, in places such as the United States, Germany, and Australia, attempts to increase protected areas are meeting strong resistance from communities, industry groups, and governments. We examined case studies of such resistance in Victoria, Australia, Bavaria, Germany, and Florida, United States. We considered 4 ways to tackle this problem. First, broaden the case for protected areas beyond nature conservation to include economic, human health, and other benefits, and translate these into a persuasive business case for protected areas. Second, better communicate the conservation values of protected areas. This should include highlighting how many species, communities, and ecosystems have been conserved by protected areas and the counterfactual (i.e., what would have been lost without protected area establishment). Third, consider zoning of activities to ensure the maintenance of effective management. Finally, remind citizens to think about conservation when they vote, including holding politicians accountable for their environmental promises. Without tackling resistance to expanding the protected estate, it will be impossible to reach conservation targets, and this will undermine attempts to stem the global extinction crisis. © 2017 Society for Conservation Biology.

Ecosystem services in European protected areas: Ambiguity in the views of scientists and managers?

NARCIS (Netherlands)

Hummel, C.; Provenzale, A.; Van der Meer, J.; Wijnhoven, S.; Nolte, A.; Poursanidis, D.; Janss, G.; Jurek, M.; Andresen, M.; Poulin, B.; Kobler, J.; Beierkuhnlein, C.; Honrado, J.; Razinkovas, A.; Stritih, A.; Bargmann, T.; Ziemba, A.; Bonet-García, F.; Adamescu, M.C.; Janssen, G.; Hummel, H.

2017-01-01

Protected Areas are a key component of nature conservation. They can play an important role in counterbalancing the impacts of ecosystem degradation. For an optimal protection of a Protected Area it is essential to account for the variables underlying the major Ecosystem Services an area delivers,

Trapping molecules in two and three dimensions

International Nuclear Information System (INIS)

Pinkse, PW.H.; Junglen, T.; Rieger, T.; Rangwala, S.A.; Windpassinger, P.; Rempe, G.

2005-01-01

Full text: Cold molecules offer a new testing ground for quantum-physical effects in nature. For example, producing slow beams of large molecules could push experiments studying the boundary between quantum interference and classical particles up towards ever heavier particles. Moreover, cold molecules, in particular YbF, seem an attractive way to narrow down the constraints on the value of the electron dipole moment and finally, quantum information processing using chains of cold polar molecules or vibrational states in molecules have been proposed. All these proposals rely on advanced production and trapping techniques, most of which are still under development. Therefore, novel production and trapping techniques for cold molecules could offer new possibilities not found in previous methods. Electric traps hold promise for deep trap potentials for neutral molecules. Recently we have demonstrated two-dimensional trapping of polar molecules in a four-wire guide using electrostatic and electrodynamic trapping techniques. Filled from a thermal effusive source, such a guide will deliver a beam of slow molecules, which is an ideal source for interferometry experiments with large molecules, for instance. Here we report about the extension of this work to three-dimensional trapping. Polar molecules with a positive Stark shift can be trapped in the minimum of an electrostatic field. We have successfully tested a large volume electrostatic trap for ND3 molecules. A special feature of this trap is that it can be loaded continuously from an electrostatic guide, at a temperature of a few hundred mK. (author)

Protecting Our Priorities: 2010 Annual Report

Science.gov (United States)

Western Interstate Commission for Higher Education, 2010

2010-01-01

What does "protecting our priorities" mean in an era when economic realities require that institutions of higher education trim their budgets while also providing critical education and training to more and more students--those "human resources" whose skills will be the key to any economic turnaround? This is a question WICHE…

What's My Lane? Identifying the State Government Role in Critical Infrastructure Protection

OpenAIRE

Donnelly, Timothy S.

2012-01-01

Approved for public release; distribution is unlimited What constitutes an effective Critical Infrastructure and Key Resources (CIKR) protection program for Massachusetts This study evaluates existing literature regarding CIKR to extrapolate an infrastructure protection role for Massachusetts. By reviewing historical events and government strategies regarding infrastructure protection, Chapters I and II will provide scope and context for issues surrounding critical infrastructure. Chapter ...

Theoretical Investigations Regarding Single Molecules

DEFF Research Database (Denmark)

Pedersen, Kim Georg Lind

Neoclassical Valence Bond Theory, Quantum Transport, Quantum Interference, Kondo Effect, and Electron Pumping. Trap a single organic molecule between two electrodes and apply a bias voltage across this "molecular junction". When electrons pass through the molecule, the different electron paths can...... interfere destructively or constructively. Destructive interference effects in electron transport could potentially improve thermo-electrics, organic logic circuits and energy harvesting. We have investigated destructive interference in off-resonant transport through organic molecules, and have found a set...

A peptide derived from a trans-homophilic binding site in neural cell adhesion molecule induces neurite outgrowth and neuronal survival

DEFF Research Database (Denmark)

Køhler, Lene B; Soroka, Vladislav; Korshunova, Irina

2010-01-01

The neural cell adhesion molecule (NCAM) plays a key role in neural development, regeneration, and synaptic plasticity. The crystal structure of a fragment of NCAM comprising the three N-terminal immunoglobulin (Ig)-like modules indicates that the first and second Ig modules bind to each other, t...

Key Distribution and Changing Key Cryptosystem Based on Phase Retrieval Algorithm and RSA Public-Key Algorithm

Directory of Open Access Journals (Sweden)

Tieyu Zhao

2015-01-01

Full Text Available The optical image encryption has attracted more and more researchers’ attention, and the various encryption schemes have been proposed. In existing optical cryptosystem, the phase functions or images are usually used as the encryption keys, and it is difficult that the traditional public-key algorithm (such as RSA, ECC, etc. is used to complete large numerical key transfer. In this paper, we propose a key distribution scheme based on the phase retrieval algorithm and the RSA public-key algorithm, which solves the problem for the key distribution in optical image encryption system. Furthermore, we also propose a novel image encryption system based on the key distribution principle. In the system, the different keys can be used in every encryption process, which greatly improves the security of the system.

Fourier domain asymmetric cryptosystem for privacy protected multimodal biometric security

Science.gov (United States)

Choudhury, Debesh

2016-04-01

We propose a Fourier domain asymmetric cryptosystem for multimodal biometric security. One modality of biometrics (such as face) is used as the plaintext, which is encrypted by another modality of biometrics (such as fingerprint). A private key is synthesized from the encrypted biometric signature by complex spatial Fourier processing. The encrypted biometric signature is further encrypted by other biometric modalities, and the corresponding private keys are synthesized. The resulting biometric signature is privacy protected since the encryption keys are provided by the human, and hence those are private keys. Moreover, the decryption keys are synthesized using those private encryption keys. The encrypted signatures are decrypted using the synthesized private keys and inverse complex spatial Fourier processing. Computer simulations demonstrate the feasibility of the technique proposed.

Radiation protection programme for uranium mining

International Nuclear Information System (INIS)

Mbeye, M.J.

2014-04-01

The Radiation Protection Programme (RPP) was developed to ensure that measures are in place for the occupational protection and safety in uranium mining facility. This work has established a number of protective measures that should be taken by the individual miners, licensee and all staff. It is not known whether Kayerekera Uranium mine has the technical and administrative capability for an effective radiation protection programme. The key in the mining facility is the control of dust through various means to prevent the escape of radon gas. Personal hygiene and local operating rules have been discovered to be very important for the protection and safety of the workers. The following components have also been discovered to be vital in ensuring safety culture in the mining facility: classification of working areas, monitoring of individuals and workplace, assignment of responsibilities, emergency preparedness, education and training and health surveillance. The regulatory body (Environmental Affairs Department of Malawi) should examine the major areas outlined in the RPP for Kayerekera uranium mine to find out the effectiveness of the RPP that is in place. (au)

Electron-molecule interactions and their applications

CERN Document Server

Christophorou, L G

1984-01-01

Electron-Molecule Interactions and Their Applications, Volume 2 provides a balanced and comprehensive account of electron-molecule interactions in dilute and dense gases and liquid media. This book consists of six chapters. Chapter 1 deals with electron transfer reactions, while Chapter 2 discusses electron-molecular positive-ion recombination. The electron motion in high-pressure gases and electron-molecule interactions from single- to multiple-collision conditions is deliberated in Chapter 3. In Chapter 4, knowledge on electron-molecule interactions in gases is linked to that on similar proc

Common Criteria for Information Technology Security Evaluation: Department of Defense Public Key Infrastructure and Key Management Infrastructure Token Protection Profile (Medium Robustness)

Science.gov (United States)

2002-03-22

may be derived from detailed inspection of the IC itself or from illicit appropriation of design information. Counterfeit smart cards can be mass...Infrastructure (PKI) as the Internet to securely and privately exchange data and money through the use of a public and a private cryptographic key pair...interference devices (SQDIS), electrical testing, and electron beam testing. • Other attacks, such as UV or X-rays or high temperatures, could cause erasure

Recent perspectives on optimisation of radiological protection

International Nuclear Information System (INIS)

Robb, J.D.; Croft, J.R.

1992-01-01

The ALARA principle as a requirement in radiological protection has evolved from its theoretical roots. Based on several years work, this paper provides a backdrop to practical approaches to ALARA for the 1990s. The key step, developing ALARA thinking so that it becomes an integral part of radiological protection programmes, is discussed using examples from the UK and France, as is the role of tools to help standardise judgements for decision-making. In its latest recommendations, ICRP have suggested that the optimisation of protection should be constrained by restrictions on the doses to individuals. This paper also considers the function of such restrictions for occupational, public and medical exposure, and in the design process. (author)

Domain-based small molecule binding site annotation

Directory of Open Access Journals (Sweden)

Dumontier Michel

2006-03-01

Full Text Available Abstract Background Accurate small molecule binding site information for a protein can facilitate studies in drug docking, drug discovery and function prediction, but small molecule binding site protein sequence annotation is sparse. The Small Molecule Interaction Database (SMID, a database of protein domain-small molecule interactions, was created using structural data from the Protein Data Bank (PDB. More importantly it provides a means to predict small molecule binding sites on proteins with a known or unknown structure and unlike prior approaches, removes large numbers of false positive hits arising from transitive alignment errors, non-biologically significant small molecules and crystallographic conditions that overpredict ion binding sites. Description Using a set of co-crystallized protein-small molecule structures as a starting point, SMID interactions were generated by identifying protein domains that bind to small molecules, using NCBI's Reverse Position Specific BLAST (RPS-BLAST algorithm. SMID records are available for viewing at http://smid.blueprint.org. The SMID-BLAST tool provides accurate transitive annotation of small-molecule binding sites for proteins not found in the PDB. Given a protein sequence, SMID-BLAST identifies domains using RPS-BLAST and then lists potential small molecule ligands based on SMID records, as well as their aligned binding sites. A heuristic ligand score is calculated based on E-value, ligand residue identity and domain entropy to assign a level of confidence to hits found. SMID-BLAST predictions were validated against a set of 793 experimental small molecule interactions from the PDB, of which 472 (60% of predicted interactions identically matched the experimental small molecule and of these, 344 had greater than 80% of the binding site residues correctly identified. Further, we estimate that 45% of predictions which were not observed in the PDB validation set may be true positives. Conclusion By

Females Are Protected From Iron-Overload Cardiomyopathy Independent of Iron Metabolism: Key Role of Oxidative Stress.

Science.gov (United States)

Das, Subhash K; Patel, Vaibhav B; Basu, Ratnadeep; Wang, Wang; DesAulniers, Jessica; Kassiri, Zamaneh; Oudit, Gavin Y

2017-01-23

Sex-related differences in cardiac function and iron metabolism exist in humans and experimental animals. Male patients and preclinical animal models are more susceptible to cardiomyopathies and heart failure. However, whether similar differences are seen in iron-overload cardiomyopathy is poorly understood. Male and female wild-type and hemojuvelin-null mice were injected and fed with a high-iron diet, respectively, to develop secondary iron overload and genetic hemochromatosis. Female mice were completely protected from iron-overload cardiomyopathy, whereas iron overload resulted in marked diastolic dysfunction in male iron-overloaded mice based on echocardiographic and invasive pressure-volume analyses. Female mice demonstrated a marked suppression of iron-mediated oxidative stress and a lack of myocardial fibrosis despite an equivalent degree of myocardial iron deposition. Ovariectomized female mice with iron overload exhibited essential pathophysiological features of iron-overload cardiomyopathy showing distinct diastolic and systolic dysfunction, severe myocardial fibrosis, increased myocardial oxidative stress, and increased expression of cardiac disease markers. Ovariectomy prevented iron-induced upregulation of ferritin, decreased myocardial SERCA2a levels, and increased NCX1 levels. 17β-Estradiol therapy rescued the iron-overload cardiomyopathy in male wild-type mice. The responses in wild-type and hemojuvelin-null female mice were remarkably similar, highlighting a conserved mechanism of sex-dependent protection from iron-overload-mediated cardiac injury. Male and female mice respond differently to iron-overload-mediated effects on heart structure and function, and females are markedly protected from iron-overload cardiomyopathy. Ovariectomy in female mice exacerbated iron-induced myocardial injury and precipitated severe cardiac dysfunction during iron-overload conditions, whereas 17β-estradiol therapy was protective in male iron-overloaded mice. �

Ground-Water Protection and Monitoring Program

Energy Technology Data Exchange (ETDEWEB)

Dresel, P.E.

1995-06-01

This section of the 1994 Hanford Site Environmental Report summarizes the ground-water protection and monitoring program strategy for the Hanford Site in 1994. Two of the key elements of this strategy are to (1) protect the unconfined aquifer from further contamination, and (2) conduct a monitoring program to provide early warning when contamination of ground water does occur. The monitoring program at Hanford is designed to document the distribution and movement of existing ground-water contamination and provides a historical baseline for evaluating current and future risk from exposure to the contamination and for deciding on remedial action options.

Ground-Water Protection and Monitoring Program

International Nuclear Information System (INIS)

Dresel, P.E.

1995-01-01

This section of the 1994 Hanford Site Environmental Report summarizes the ground-water protection and monitoring program strategy for the Hanford Site in 1994. Two of the key elements of this strategy are to (1) protect the unconfined aquifer from further contamination, and (2) conduct a monitoring program to provide early warning when contamination of ground water does occur. The monitoring program at Hanford is designed to document the distribution and movement of existing ground-water contamination and provides a historical baseline for evaluating current and future risk from exposure to the contamination and for deciding on remedial action options

Interstellar Molecules

Science.gov (United States)

Solomon, Philip M.

1973-01-01

Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

Practical private database queries based on a quantum-key-distribution protocol

International Nuclear Information System (INIS)

Jakobi, Markus; Simon, Christoph; Gisin, Nicolas; Bancal, Jean-Daniel; Branciard, Cyril; Walenta, Nino; Zbinden, Hugo

2011-01-01

Private queries allow a user, Alice, to learn an element of a database held by a provider, Bob, without revealing which element she is interested in, while limiting her information about the other elements. We propose to implement private queries based on a quantum-key-distribution protocol, with changes only in the classical postprocessing of the key. This approach makes our scheme both easy to implement and loss tolerant. While unconditionally secure private queries are known to be impossible, we argue that an interesting degree of security can be achieved by relying on fundamental physical principles instead of unverifiable security assumptions in order to protect both the user and the database. We think that the scope exists for such practical private queries to become another remarkable application of quantum information in the footsteps of quantum key distribution.

Liv. 52 protection against radiation induced lesions in mammalian liver

International Nuclear Information System (INIS)

Saini, M.R.; Saini, N.

1985-01-01

Effect of Liv. 52 on mammalian liver was studied after whole-body exposure to 5.5 Gy of 60 Co gamma radiation. It was found that the drug protected the organ against radiation-induced changes. The protective effect was manifested in the form of early recovery as indicated by the absence of pathological changes like cytoplasmic degranulation, loss of nulei from many cells and abnormal architecture at 10 days and restoration of normal structure by 4 weeks. Liv. 52 may neutralize the peroxides formed from water molecules after irradiation which are toxic and cause the damage to the organ. Thus it seems that the drug may act as detoxicating agent. (author)

Degradation and protection of DNAzymes on human skin.

Science.gov (United States)

Marquardt, Kay; Eicher, Anna-Carola; Dobler, Dorota; Höfer, Frank; Schmidts, Thomas; Schäfer, Jens; Renz, Harald; Runkel, Frank

2016-10-01

DNAzymes are catalytic nucleic acid based molecules that have become a new class of active pharmaceutical ingredients (API). Until now, five DNAzymes have entered clinical trials. Two of them were tested for topical application, whereby dermally applied DNAzymes had been prone to enzymatic degradation. To protect the DNAzymes the enzymatic activity of human skin has to be examined. Therefore, the enzymatic activity of human skin was qualitatively and quantitatively analyzed. Activity similar to that of DNase II could be identified and the specific activity was determined to be 0.59Units/mg. These results were used to develop an in vitro degradation assay to screen different kinds of protective systems on human skin. The chosen protective systems consisted of biodegradable chitosans or polyethylenimine, which forms polyplexes when combined with DNAzymes. The polyplexes were characterized in terms of particle size, zeta potential, stability and degree of complexation. The screening revealed that the protective efficiency of the polyplexes depended on the polycation and the charge ratio (ξ). At a critical ξ ratio between 1.0 and 4.1 and at a maximal zeta potential, sufficient protection of the DNAzyme was achieved. The results of this study will be helpful for the development of a protective dermal drug delivery systems using polyplexes. Copyright © 2016 Elsevier B.V. All rights reserved.

A Privacy Protection User Authentication and Key Agreement Scheme Tailored for the Internet of Things Environment: PriAuth

Directory of Open Access Journals (Sweden)

Yuwen Chen

2017-01-01

Full Text Available In a wearable sensor-based deployment, sensors are placed over the patient to monitor their body health parameters. Continuous physiological information monitored by wearable sensors helps doctors have a better diagnostic and a suitable treatment. When doctors want to access the patient’s sensor data remotely via network, the patient will authenticate the identity of the doctor first, and then they will negotiate a key for further communication. Many lightweight schemes have been proposed to enable a mutual authentication and key establishment between the two parties with the help of a gateway node, but most of these schemes cannot enable identity confidentiality. Besides, the shared key is also known by the gateway, which means the patient’s sensor data could be leaked to the gateway. In PriAuth, identities are encrypted to guarantee confidentiality. Additionally, Elliptic Curve Diffie–Hellman (ECDH key exchange protocol has been adopted to ensure the secrecy of the key, avoiding the gateway access to it. Besides, only hash and XOR computations are adopted because of the computability and power constraints of the wearable sensors. The proposed scheme has been validated by BAN logic and AVISPA, and the results show the scheme has been proven as secure.

Theory of the reaction dynamics of small molecules on metal surfaces

Energy Technology Data Exchange (ETDEWEB)

Jackson, Bret [Univ. of Massachusetts, Amherst, MA (United States)

2016-09-09

The objective of this project has been to develop realistic theoretical models for gas-surface interactions, with a focus on processes important in heterogeneous catalysis. The dissociative chemisorption of a molecule on a metal is a key step in many catalyzed reactions, and is often the rate-limiting step. We have explored the dissociative chemisorption of H₂, H₂O and CH₄ on a variety of metal surfaces. Most recently, our extensive studies of methane dissociation on Ni and Pt surfaces have fully elucidated its dependence on translational energy, vibrational state and surface temperature, providing the first accurate comparisons with experimental data. We have explored Eley-Rideal and hot atom reactions of H atoms with H- and C-covered metal surfaces. H atom interactions with graphite have also been explored, including both sticking and Eley-Rideal recombination processes. Again, our methods made it possible to explain several experiments studying these reactions. The sticking of atoms on metal surfaces has also been studied. To help elucidate the experiments that study these processes, we examine how the reaction dynamics depend upon the nature of the molecule-metal interaction, as well as experimental variables such as substrate temperature, beam energy, angle of impact, and the internal states of the molecules. Electronic structure methods based on Density Functional Theory are used to compute each molecule-metal potential energy surface. Both time-dependent quantum scattering techniques and quasi-classical methods are used to examine the reaction or scattering dynamics. Much of our effort has been directed towards developing improved quantum methods that can accurately describe reactions, as well as include the effects of substrate temperature (lattice vibration).

Activation of TRPM7 channels by small molecules under physiological conditions.

Science.gov (United States)

Hofmann, T; Schäfer, S; Linseisen, M; Sytik, L; Gudermann, T; Chubanov, V

2014-12-01

Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) is a cation channel covalently linked to a protein kinase domain. TRPM7 is ubiquitously expressed and regulates key cellular processes such as Mg(2+) homeostasis, motility, and proliferation. TRPM7 is involved in anoxic neuronal death, cardiac fibrosis, and tumor growth. The goal of this work was to identify small molecule activators of the TRPM7 channel and investigate their mechanism of action. We used an aequorin bioluminescence-based assay to screen for activators of the TRPM7 channel. Valid candidates were further characterized using patch clamp electrophysiology. We identified 20 drug-like compounds with various structural backbones that can activate the TRPM7 channel. Among them, the δ opioid antagonist naltriben was studied in greater detail. Naltriben's action was selective among the TRP channels tested. Naltriben activates TRPM7 currents without prior depletion of intracellular Mg(2+) even under conditions of low PIP2. Moreover, naltriben interfered with the effect of the TRPM7 inhibitor NS8593. Finally, our experiments with TRPM7 variants carrying mutations in the pore, TRP, and kinase domains indicate that the site of TRPM7 activation by this small-molecule ligand is most likely located in or near the TRP domain. In conclusion, we identified the first organic small-molecule activators of TRPM7 channels, thus providing new experimental tools to study TRPM7 function in native cellular environments.

USING RF TECHNOLOGY FOR PROTECTED ASSET TRACKING

International Nuclear Information System (INIS)

Younkin, James R.; Pickett, Chris A.; Richardson, Dave; Stinson, Brad J.

2008-01-01

The Oak Ridge National Laboratory (ORNL) is working on systems that use a new radio frequency (RF) technology called Rubee to manage and inventory many types of protected assets, including weapons housed in Department of Energy (DOE) armories, tooling, and nuclear material containers. Rubee is being considered for an IEEE Standard, and is used on several projects at ORNL because of its high performance when used in, on, and around metal-an environment that is typical of that found in an armory vault and that of many other protected assets locations within nuclear facilities. The primary objective using Rubee is to supply sustainable technology that provides timely information on the status and location of protected assets. This paper focuses on the results from a deployment of this technology at a DOE armory and discusses the applicability of Rubee for use with other protected assets within nuclear facilities. Key Words: Rubee, low radio frequency, protected assets

Efficient biometric authenticated key agreements based on extended chaotic maps for telecare medicine information systems.

Science.gov (United States)

Lou, Der-Chyuan; Lee, Tian-Fu; Lin, Tsung-Hung

2015-05-01

Authenticated key agreements for telecare medicine information systems provide patients, doctors, nurses and health visitors with accessing medical information systems and getting remote services efficiently and conveniently through an open network. In order to have higher security, many authenticated key agreement schemes appended biometric keys to realize identification except for using passwords and smartcards. Due to too many transmissions and computational costs, these authenticated key agreement schemes are inefficient in communication and computation. This investigation develops two secure and efficient authenticated key agreement schemes for telecare medicine information systems by using biometric key and extended chaotic maps. One scheme is synchronization-based, while the other nonce-based. Compared to related approaches, the proposed schemes not only retain the same security properties with previous schemes, but also provide users with privacy protection and have fewer transmissions and lower computational cost.

Phosphate Activation via Reduced Oxidation State Phosphorus (P. Mild Routes to Condensed-P Energy Currency Molecules

Directory of Open Access Journals (Sweden)

Claire R. Cousins

2013-07-01

Full Text Available The emergence of mechanisms for phosphorylating organic and inorganic molecules is a key step en route to the earliest living systems. At the heart of all contemporary biochemical systems reside reactive phosphorus (P molecules (such as adenosine triphosphate, ATP as energy currency molecules to drive endergonic metabolic processes and it has been proposed that a predecessor of such molecules could have been pyrophosphate [P2O74−; PPi(V]. Arguably the most geologically plausible route to PPi(V is dehydration of orthophosphate, Pi(V, normally a highly endergonic process in the absence of mechanisms for activating Pi(V. One possible solution to this problem recognizes the presence of reactive-P containing mineral phases, such as schreibersite [(Fe,Ni3P] within meteorites whose abundance on the early Earth would likely have been significant during a putative Hadean-Archean heavy bombardment. Here, we propose that the reduced oxidation state P-oxyacid, H-phosphite [HPO32−; Pi(III] could have activated Pi(V towards condensation via the intermediacy of the condensed oxyacid pyrophosphite [H2P2O52−; PPi(III]. We provide geologically plausible provenance for PPi(III along with evidence of its ability to activate Pi(V towards PPi(V formation under mild conditions (80 °C in water.

Electrochemically-gated single-molecule electrical devices

International Nuclear Information System (INIS)

Guo, Shaoyin; Artés, Juan Manuel; Díez-Pérez, Ismael

2013-01-01

In the last decade, single-molecule electrical contacts have emerged as a new experimental platform that allows exploring charge transport phenomena in individual molecular blocks. This novel tool has evolved into an essential element within the Molecular Electronics field to understand charge transport processes in hybrid (bio)molecule/electrode interfaces at the nanoscale, and prospect the implementation of active molecular components into functional nanoscale optoelectronic devices. Within this area, three-terminal single-molecule devices have been sought, provided that they are highly desired to achieve full functionality in logic electronic circuits. Despite the latest experimental developments offer consistent methods to bridge a molecule between two electrodes (source and drain in a transistor notation), placing a third electrode (gate) close to the single-molecule electrical contact is still technically challenging. In this vein, electrochemically-gated single-molecule devices have emerged as an experimentally affordable alternative to overcome these technical limitations. In this review, the operating principle of an electrochemically-gated single-molecule device is presented together with the latest experimental methodologies to built them and characterize their charge transport characteristics. Then, an up-to-date comprehensive overview of the most prominent examples will be given, emphasizing on the relationship between the molecular structure and the final device electrical behaviour

ZAP-70 and p72syk are signaling response elements through MHC class II molecules

DEFF Research Database (Denmark)

Kanner, S B; Grosmaire, L S; Blake, J

1995-01-01

Ligation of major histocompatibility complex (MHC) class II antigens expressed on antigen-activated human CD4+ T-lymphocytes induces early signal transduction events including the activation of tyrosine kinases, the tyrosine phosphorylation of phospholipase-C gamma 1 and the mobilization...... of intracellular calcium. Similar responses have been observed in B-cells following stimulation of MHC class II molecules, including the increased production of intracellular cAMP. In this report, we demonstrate that the ZAP-70 tyrosine kinase is a responsive signaling element following cross-linking of HLA...... by herbimycin A. MHC class II ligation on B-lymphocytes resulted in cell death, which was both qualitatively distinct from Fas-induced apoptosis and partially protected by herbimycin A pretreatment. Thus, ligation of MHC class II molecules expressed on human lymphocytes stimulates the ZAP-70/p72syk family...

Radiation protection problems in a laboratory for the labelling of molecules with carbon-11

International Nuclear Information System (INIS)

Vialettes, H.; Moreau, A.

1980-03-01

This paper shows that the qualities of carbon-11, especially its short half-life, which suit it so well for the labelling of radiopharmaceuticals prove to be a great handicap in the preparation of these substances. The operator has to make a fresh preparation for each examination and start with strong radioactivities (200 to 500 mCi) in order to obtain an adequate injected activity at the end of the process, the absorbed dose averaging 1.5 man-rem per manipulation at the fingertips. The development of an automatic preparation method involving as little manual interference as possible has halved the collective dose for twice the dose handled. The labelling of molecules used for diagnosis is now considered to take place under satisfactory radioprotection conditions. The fingertip irradiations are analysed in the light of CIPR recommendations, while regretting that in publication 26 this problem of partial external irradiation of the skin is not dealt with as clearly and precisely as before [fr

Single molecule approaches for quantifying transcription and degradation rates in intact mammalian tissues.

Science.gov (United States)

Bahar Halpern, Keren; Itzkovitz, Shalev

2016-04-01

A key challenge in mammalian biology is to understand how rates of transcription and mRNA degradation jointly shape cellular gene expression. Powerful techniques have been developed for measuring these rates either genome-wide or at the single-molecule level, however these techniques are not applicable to assessment of cells within their native tissue microenvironment. Here we describe a technique based on single molecule Fluorescence in-situ Hybridization (smFISH) to measure transcription and degradation rates in intact mammalian tissues. The technique is based on dual-color libraries targeting the introns and exons of the genes of interest, enabling visualization and quantification of both nascent and mature mRNA. We present a software, TransQuant, that facilitates quantifying these rates from smFISH images. Our approach enables assessment of both transcription and degradation rates of any gene of interest while controlling for the inherent heterogeneity of intact tissues. Copyright © 2015 Elsevier Inc. All rights reserved.

Developing conservation governance strategies: holistic management of protected areas in Nepal

OpenAIRE

Budhathoki, Prabhu

2012-01-01

The Buffer Zone (BZ) concept has been introduced in Nepal as a key component of the national biodiversity conservation strategy to mitigate the impacts of protected areas on local communities, and thereby reduce adverse impacts of local people on protected areas. Unlike traditional Buffer Zone programmes which are mostly limited to creating a protective layer and/or distributing economic benefits to local people, the Buffer Zone management approach in Nepal integrates livelihoods and conserva...

Passage Key Inlet, Florida; CMS Modeling and Borrow Site Impact Analysis

Science.gov (United States)

2016-06-01

Impact Analysis by Kelly R. Legault and Sirisha Rayaprolu PURPOSE: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the...driven sediment transport at Passage Key Inlet. This analysis resulted in issuing a new Florida Department of Environmental Protection (FDEP) permit to...Funding for this study was provided by the USACE Regional Sediment Management (RSM) Program, a Navigation Research, Development, and Technology Portfolio

Characterizing and engineering tunable spin functionality inside indium arsenide/gallium arsenide quantum dot molecules

Science.gov (United States)

Liu, Weiwen

The continual downsizing of the basic functional units used in the electronics industry has motivated the study of the quantum computation and related topics. To overcome the limitations of classical physics and engineering, some unique quantum mechanical features, especially entanglement and superpositions have begun to be considered as important properties for future bits. Including these quantum mechanical features is attractive because the ability to utilize quantum mechanics can dramatically enhance computational power. Among the various ways of constructing the basic building blocks for quantum computation, we are particularly interested in using spins inside epitaxially grown InAs/GaAs quantum dot molecules as quantum bits (qubits). The ability to design and engineer nanostructures with tailored quantum properties is critical to engineering quantum computers and other novel electro-optical devices and is one of the key challenges for scaling up new ideas for device application. In this thesis, we will focus on how the structure and composition of quantum dot molecules can be used to control spin properties and charge interactions. Tunable spin and charge properties can enable new, more scalable, methods of initializing and manipulating quantum information. In this thesis, we demonstrate one method to enable electric-field tunability of Zeeman splitting for a single electron spin inside a quantum dot molecules by using heterostructure engineering techniques to modify the barrier that separates quantum dots. We describe how these structural changes to the quantum dot molecules also change charge interactions and propose ways to use this effect to enable accurate measurement of coulomb interactions and possibly charge occupancy inside these complicated quantum dot molecules.

Seaweed Polysaccharides and Derived Oligosaccharides Stimulate Defense Responses and Protection Against Pathogens in Plants

Directory of Open Access Journals (Sweden)

Alejandra Moenne

2011-11-01

Full Text Available Plants interact with the environment by sensing “non-self” molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been shown that cell wall and storage polysaccharides from green, brown and red seaweeds (marine macroalgae corresponding to ulvans, alginates, fucans, laminarin and carrageenans can trigger defense responses in plants enhancing protection against pathogens. In addition, oligosaccharides obtained by depolymerization of seaweed polysaccharides also induce protection against viral, fungal and bacterial infections in plants. In particular, most seaweed polysaccharides and derived oligosaccharides trigger an initial oxidative burst at local level and the activation of salicylic (SA, jasmonic acid (JA and/or ethylene signaling pathways at systemic level. The activation of these signaling pathways leads to an increased expression of genes encoding: (i Pathogenesis-Related (PR proteins with antifungal and antibacterial activities; (ii defense enzymes such as pheylalanine ammonia lyase (PAL and lipoxygenase (LOX which determine accumulation of phenylpropanoid compounds (PPCs and oxylipins with antiviral, antifugal and antibacterial activities and iii enzymes involved in synthesis of terpenes, terpenoids and/or alkaloids having antimicrobial activities. Thus, seaweed polysaccharides and their derived oligosaccharides induced the accumulation of proteins and compounds with antimicrobial activities that determine, at least in part, the enhanced protection against pathogens in plants.

Engineering and control of cold molecules. Making manipulating and exploiting ultra-cold polar molecules

International Nuclear Information System (INIS)

Bigelow, N.P.; Haimberger, C.; Kleinert, J.; Tscherneck, M.; Holmes, M.E.

2005-01-01

In the last 12 months several groups have demonstrated the use of photo association to create cold heteronuclear (polar) molecules. We report on the formation of translationally cold NaCs molecules starting from a laser-cooled atomic vapor of Na and Cs atoms. Colliding atoms are transferred into bound molecular states in a two-step photoactivated process. We find a translational temperature of T ≅ 260 mK. To increase the density and number of trapped atoms, dark-spot techniques are used on the MOT and a Zeeman slowed sodium beam is used to load the sodium atoms into the trap. Spectroscopy of these molecules is underway using time-of-flight ion detection and trap-loss. Initial REMPI measurements indicate that both singlet and triplet states are being populated by the spontaneous-decay driven process. We measure a rate constant for molecule formation of K NaCs = 7.43 · 10 15 cm 3 s -1 . (author)

Formation of ultracold NaRb Feshbach molecules

International Nuclear Information System (INIS)

Wang, Fudong; He, Xiaodong; Li, Xiaoke; Zhu, Bing; Chen, Jun; Wang, Dajun

2015-01-01

We report the creation of ultracold bosonic 23 Na 87 Rb Feshbach molecules via magneto-association. By ramping the magnetic field across an interspecies Feshbach resonance (FR), at least 4000 molecules can be produced out of the near degenerate ultracold mixture. Fast loss due to inelastic atom–molecule collisions is observed, which limits the pure molecule number, after residual atoms removal, to 1700. The pure molecule sample can live for 21.8(8) ms in the optical trap, long enough for future molecular spectroscopy studies toward coherently transferring to the singlet ro-vibrational ground state, where these molecules are stable against chemical reaction and have a permanent electric dipole moment of 3.3 Debye. We have also measured the Feshbach molecule’s binding energy near the FR by the oscillating magnetic field method and found these molecules have a large closed-channel fraction. (paper)

Quantum transport through organic molecules

International Nuclear Information System (INIS)

Maiti, Santanu K.

2007-01-01

We investigate the electronic transport for the model of benzene-1, 4-dithiolate (BDT) molecule and some other geometric models of benzene molecule attached with two semi-infinite metallic electrodes by the use of Green's function technique. An analytic approach for the electronic transport through the molecular bridges is presented, based on the tight-binding model. Transport of electrons in such molecular bridges is strongly affected by the geometry of the molecules and their coupling strength with the electrodes. Conductance (g) shows resonance peaks associated with the molecular energy eigenstates. In the weak molecule-to-electrodes coupling limit current (I) passing through the molecules shows staircase-like behavior with sharp steps, while, it varies quite continuously in the limit of strong molecular coupling with the applied bias voltage (V). In presence of the transverse magnetic field conductance gives oscillatory behavior with flux φ, threaded by the molecular ring, showing φ 0 ( = ch/e) flux-quantum periodicity. Though conductance changes with the application of transverse magnetic field, but the current-voltage characteristics remain same in presence of this magnetic field for these molecular bridge systems

In Planta Single-Molecule Pull-Down Reveals Tetrameric Stoichiometry of HD-ZIPIII:LITTLE ZIPPER Complexes.

Science.gov (United States)

Husbands, Aman Y; Aggarwal, Vasudha; Ha, Taekjip; Timmermans, Marja C P

2016-08-01

Deciphering complex biological processes markedly benefits from approaches that directly assess the underlying biomolecular interactions. Most commonly used approaches to monitor protein-protein interactions typically provide nonquantitative readouts that lack statistical power and do not yield information on the heterogeneity or stoichiometry of protein complexes. Single-molecule pull-down (SiMPull) uses single-molecule fluorescence detection to mitigate these disadvantages and can quantitatively interrogate interactions between proteins and other compounds, such as nucleic acids, small molecule ligands, and lipids. Here, we establish SiMPull in plants using the HOMEODOMAIN LEUCINE ZIPPER III (HD-ZIPIII) and LITTLE ZIPPER (ZPR) interaction as proof-of-principle. Colocalization analysis of fluorophore-tagged HD-ZIPIII and ZPR proteins provides strong statistical evidence of complex formation. In addition, we use SiMPull to directly quantify YFP and mCherry maturation probabilities, showing these differ substantially from values obtained in mammalian systems. Leveraging these probabilities, in conjunction with fluorophore photobleaching assays on over 2000 individual complexes, we determined HD-ZIPIII:ZPR stoichiometry. Intriguingly, these complexes appear as heterotetramers, comprising two HD-ZIPIII and two ZPR molecules, rather than heterodimers as described in the current model. This surprising result raises new questions about the regulation of these key developmental factors and is illustrative of the unique contribution SiMPull is poised to make to in planta protein interaction studies. © 2016 American Society of Plant Biologists. All rights reserved.

Spectrally resolved single-molecule electrometry

Science.gov (United States)

Ruggeri, F.; Krishnan, M.

2018-03-01

Escape-time electrometry is a recently developed experimental technique that offers the ability to measure the effective electrical charge of a single biomolecule in solution with sub-elementary charge precision. The approach relies on measuring the average escape-time of a single charged macromolecule or molecular species transiently confined in an electrostatic fluidic trap. Comparing the experiments with the predictions of a mean-field model of molecular electrostatics, we have found that the measured effective charge even reports on molecular conformation, e.g., folded or disordered state, and non-uniform charge distribution in disordered proteins or polyelectrolytes. Here we demonstrate the ability to use the spectral dimension to distinguish minute differences in electrical charge between individual molecules or molecular species in a single simultaneous measurement, under identical experimental conditions. Using one spectral channel for referenced measurement, this kind of photophysical distinguishability essentially eliminates the need for accurate knowledge of key experimental parameters, otherwise obtained through intensive characterization of the experimental setup. As examples, we demonstrate the ability to detect small differences (˜5%) in the length of double-stranded DNA fragments as well as single amino acid exchange in an intrinsically disordered protein, prothymosin α.

Fluorescent Biosensors Based on Single-Molecule Counting.

Science.gov (United States)

Ma, Fei; Li, Ying; Tang, Bo; Zhang, Chun-Yang

2016-09-20

Biosensors for highly sensitive, selective, and rapid quantification of specific biomolecules make great contributions to biomedical research, especially molecular diagnostics. However, conventional methods for biomolecular assays often suffer from insufficient sensitivity and poor specificity. In some case (e.g., early disease diagnostics), the concentration of target biomolecules is too low to be detected by these routine approaches, and cumbersome procedures are needed to improve the detection sensitivity. Therefore, there is an urgent need for rapid and ultrasensitive analytical tools. In this respect, single-molecule fluorescence approaches may well satisfy the requirement and hold promising potential for the development of ultrasensitive biosensors. Encouragingly, owing to the advances in single-molecule microscopy and spectroscopy over past decades, the detection of single fluorescent molecule comes true, greatly boosting the development of highly sensitive biosensors. By in vitro/in vivo labeling of target biomolecules with proper fluorescent tags, the quantification of certain biomolecule at the single-molecule level is achieved. In comparison with conventional ensemble measurements, single-molecule detection-based analytical methods possess the advantages of ultrahigh sensitivity, good selectivity, rapid analysis time, and low sample consumption. Consequently, single-molecule detection may be potentially employed as an ideal analytical approach to quantify low-abundant biomolecules with rapidity and simplicity. In this Account, we will summarize our efforts for developing a series of ultrasensitive biosensors based on single-molecule counting. Single-molecule counting is a member of single-molecule detection technologies and may be used as a very simple and ultrasensitive method to quantify target molecules by simply counting the individual fluorescent bursts. In the fluorescent sensors, the signals of target biomolecules may be translated to the

Selectivity of primary events in the radiation chemistry of organic solids and polymers as revealed by model studies of ionized molecules

International Nuclear Information System (INIS)

Feldman, V.

2006-01-01

Selectivity of the primary chemical events induced by ionizing radiation in molecular systems is the key issue of basic radiation chemistry, which is crucially important for controlling the radiation sensitivity of various-type organic and polymeric materials and designing new effective approaches to the radiation modification. In the past decade we have demonstrated that many features of selective localization of the radiation-induced effects in molecular solids can be understood on the basis of model studies of the primary ionized molecules in rigid low-temperature matrices. This talk will outline the key results of these studies and possible implications for radiation chemistry of vatious systems. In particular, the following aspects will be considered: (1) Spectroscopic characteristics of ustable ionized molecules in low-temperature matrices and their correlations with the site-selective reactivity. (2) Experimental modeling of the effect of excess energy on the properties of primary ionized molecules in condensed phases. (3) Intramolecular long-range effects with particular impact on the properties of ionized bifunctional molecules of X-(CH 2 ) n -X and X-(CH 2 ) n -Y types. (4) Modeling of intermolecular long-range positive hole transfer between molecular traps with close ionization energy and manifestations of 'fine tuning' effects resulting from conformation variations and intermolecular interactions. Several illustrative examples of correlation between the properties of primary ionized molecules and selectivity of the radiation-chemical transformations in organic solids and macromolecules will be presented. Finally, the problem of prediction of the radiation-chemical behaviour of complex organic systems on the basis of limited spectroscopic information and quantum-chemical data obtained for model systems will be addressed. This work was supported by the Russian Foundation for Basic Research (Project No. 06-03-33104) and the Russian Academy of Sciences

Simple Web-based interactive key development software (WEBiKEY) and an example key for Kuruna (Poaceae: Bambusoideae).

Science.gov (United States)

Attigala, Lakshmi; De Silva, Nuwan I; Clark, Lynn G

2016-04-01

Programs that are user-friendly and freely available for developing Web-based interactive keys are scarce and most of the well-structured applications are relatively expensive. WEBiKEY was developed to enable researchers to easily develop their own Web-based interactive keys with fewer resources. A Web-based multiaccess identification tool (WEBiKEY) was developed that uses freely available Microsoft ASP.NET technologies and an SQL Server database for Windows-based hosting environments. WEBiKEY was tested for its usability with a sample data set, the temperate woody bamboo genus Kuruna (Poaceae). WEBiKEY is freely available to the public and can be used to develop Web-based interactive keys for any group of species. The interactive key we developed for Kuruna using WEBiKEY enables users to visually inspect characteristics of Kuruna and identify an unknown specimen as one of seven possible species in the genus.

Energy storage and redistribution in molecules

International Nuclear Information System (INIS)

Hinze, J.

1983-01-01

This book presents information on the following topics: chemistry and spectroscopy of molecules at high levels of excitation; energy and phase randomization in large molecules as probed by laser spectroscopy; intramolecular processes in isolated polyatomic molecules; pulse-probe measurements in low-temperature, low-pressure SF 6 ; the photodissociation dynamics of H 2 S and CF 3 NO; photofragment spectroscopy of the NO 2 dissociation; preparation, laser spectroscopy and predissociation of alkali dimers in supersonic nozzle beams; excited states of small molecules - collisional quenching and photodissociation; quantum-state-resolved scattering of lithium hydride; and molecular negative ions

Molecule-oriented programming in Java

NARCIS (Netherlands)

Bergstra, J.A.

2002-01-01

Molecule-oriented programming is introduced as a programming style carrying some perspective for Java. A sequence of examples is provided. Supporting the development of the molecule-oriented programming style several matters are introduced and developed: profile classes allowing the representation

Novel Multi-Party Quantum Key Agreement Protocol with G-Like States and Bell States

Science.gov (United States)

Min, Shi-Qi; Chen, Hua-Ying; Gong, Li-Hua

2018-06-01

A significant aspect of quantum cryptography is quantum key agreement (QKA), which ensures the security of key agreement protocols by quantum information theory. The fairness of an absolute security multi-party quantum key agreement (MQKA) protocol demands that all participants can affect the protocol result equally so as to establish a shared key and that nobody can determine the shared key by himself/herself. We found that it is difficult for the existing multi-party quantum key agreement protocol to withstand the collusion attacks. Put differently, it is possible for several cooperated and untruthful participants to determine the final key without being detected. To address this issue, based on the entanglement swapping between G-like state and Bell states, a new multi-party quantum key agreement protocol is put forward. The proposed protocol makes full use of EPR pairs as quantum resources, and adopts Bell measurement and unitary operation to share a secret key. Besides, the proposed protocol is fair, secure and efficient without involving a third party quantum center. It demonstrates that the protocol is capable of protecting users' privacy and meeting the requirement of fairness. Moreover, it is feasible to carry out the protocol with existing technologies.

Novel Multi-Party Quantum Key Agreement Protocol with G-Like States and Bell States

Science.gov (United States)

Min, Shi-Qi; Chen, Hua-Ying; Gong, Li-Hua

2018-03-01

A significant aspect of quantum cryptography is quantum key agreement (QKA), which ensures the security of key agreement protocols by quantum information theory. The fairness of an absolute security multi-party quantum key agreement (MQKA) protocol demands that all participants can affect the protocol result equally so as to establish a shared key and that nobody can determine the shared key by himself/herself. We found that it is difficult for the existing multi-party quantum key agreement protocol to withstand the collusion attacks. Put differently, it is possible for several cooperated and untruthful participants to determine the final key without being detected. To address this issue, based on the entanglement swapping between G-like state and Bell states, a new multi-party quantum key agreement protocol is put forward. The proposed protocol makes full use of EPR pairs as quantum resources, and adopts Bell measurement and unitary operation to share a secret key. Besides, the proposed protocol is fair, secure and efficient without involving a third party quantum center. It demonstrates that the protocol is capable of protecting users' privacy and meeting the requirement of fairness. Moreover, it is feasible to carry out the protocol with existing technologies.

MOLECULES IN η CARINAE

International Nuclear Information System (INIS)

Loinard, Laurent; Menten, Karl M.; Güsten, Rolf; Zapata, Luis A.; Rodríguez, Luis F.

2012-01-01

We report the detection toward η Carinae of six new molecules, CO, CN, HCO + , HCN, HNC, and N 2 H + , and of two of their less abundant isotopic counterparts, 13 CO and H 13 CN. The line profiles are moderately broad (∼100 km s –1 ), indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO + do not appear to be underabundant in η Carinae. On the other hand, molecules containing nitrogen or the 13 C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of η Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

Single-molecule dataset (SMD): a generalized storage format for raw and processed single-molecule data.

Science.gov (United States)

Greenfeld, Max; van de Meent, Jan-Willem; Pavlichin, Dmitri S; Mabuchi, Hideo; Wiggins, Chris H; Gonzalez, Ruben L; Herschlag, Daniel

2015-01-16

Single-molecule techniques have emerged as incisive approaches for addressing a wide range of questions arising in contemporary biological research [Trends Biochem Sci 38:30-37, 2013; Nat Rev Genet 14:9-22, 2013; Curr Opin Struct Biol 2014, 28C:112-121; Annu Rev Biophys 43:19-39, 2014]. The analysis and interpretation of raw single-molecule data benefits greatly from the ongoing development of sophisticated statistical analysis tools that enable accurate inference at the low signal-to-noise ratios frequently associated with these measurements. While a number of groups have released analysis toolkits as open source software [J Phys Chem B 114:5386-5403, 2010; Biophys J 79:1915-1927, 2000; Biophys J 91:1941-1951, 2006; Biophys J 79:1928-1944, 2000; Biophys J 86:4015-4029, 2004; Biophys J 97:3196-3205, 2009; PLoS One 7:e30024, 2012; BMC Bioinformatics 288 11(8):S2, 2010; Biophys J 106:1327-1337, 2014; Proc Int Conf Mach Learn 28:361-369, 2013], it remains difficult to compare analysis for experiments performed in different labs due to a lack of standardization. Here we propose a standardized single-molecule dataset (SMD) file format. SMD is designed to accommodate a wide variety of computer programming languages, single-molecule techniques, and analysis strategies. To facilitate adoption of this format we have made two existing data analysis packages that are used for single-molecule analysis compatible with this format. Adoption of a common, standard data file format for sharing raw single-molecule data and analysis outcomes is a critical step for the emerging and powerful single-molecule field, which will benefit both sophisticated users and non-specialists by allowing standardized, transparent, and reproducible analysis practices.

Key aspects to perform a project on energy management

International Nuclear Information System (INIS)

Bachini, R.

1993-01-01

A general overview on elements and organisms playing a key role to launch a new industrial project is given, taking as base case an energy management project. Likewise the problematic of training personnel involved in the project is analyzed. Energy management becomes crucial in industries where energy costs represent a big portion of the whole production cost. Main aspects to be analyzed are: - Adequate production procedures to be competitive - Environment protection regarding waste management - Maximization of safety at production installations. (Author)

Long distance free-space quantum key distribution

International Nuclear Information System (INIS)

Schmitt-Manderbach, T.

2007-01-01

The aim of the presented experiment was to investigate the feasibility of satellite-based global quantum key distribution. In this context, a free-space quantum key distribution experiment over a real distance of 144 km was performed. The transmitter and the receiver were situated in 2500 m altitude on the Canary Islands of La Palma and Tenerife, respectively. The small and compact transmitter unit generated attenuated laser pulses, that were sent to the receiver via a 15-cm optical telescope. The receiver unit for polarisation analysis and detection of the sent pulses was integrated into an existing mirror telescope designed for classical optical satellite communications. To ensure the required stability and efficiency of the optical link in the presence of atmospheric turbulence, the two telescopes were equipped with a bi-directional automatic tracking system. Still, due to stray light and high optical attenuation, secure key exchange would not be possible using attenuated pulses in connection with the standard BB84 protocol. The photon number statistics of attenuated pulses follows a Poissonian distribution. Hence, by removing a photon from all pulses containing two or more photons, an eavesdropper could measure its polarisation without disturbing the polarisation state of the remaining pulse. In this way, he can gain information about the key without introducing detectable errors. To protect against such attacks, the presented experiment employed the recently developed method of using additional ''decoy'' states, i.e., the the intensity of the pulses created by the transmitter were varied in a random manner. By analysing the detection probabilities of the different pulses individually, a photon-number-splitting attack can be detected. Thanks to the decoy-state analysis, the secrecy of the resulting quantum key could be ensured despite the Poissonian nature of the emitted pulses. For a channel attenuation as high as 35 dB, a secret key rate of up to 250 bit

Long distance free-space quantum key distribution

Energy Technology Data Exchange (ETDEWEB)

Schmitt-Manderbach, T.

2007-10-16

The aim of the presented experiment was to investigate the feasibility of satellite-based global quantum key distribution. In this context, a free-space quantum key distribution experiment over a real distance of 144 km was performed. The transmitter and the receiver were situated in 2500 m altitude on the Canary Islands of La Palma and Tenerife, respectively. The small and compact transmitter unit generated attenuated laser pulses, that were sent to the receiver via a 15-cm optical telescope. The receiver unit for polarisation analysis and detection of the sent pulses was integrated into an existing mirror telescope designed for classical optical satellite communications. To ensure the required stability and efficiency of the optical link in the presence of atmospheric turbulence, the two telescopes were equipped with a bi-directional automatic tracking system. Still, due to stray light and high optical attenuation, secure key exchange would not be possible using attenuated pulses in connection with the standard BB84 protocol. The photon number statistics of attenuated pulses follows a Poissonian distribution. Hence, by removing a photon from all pulses containing two or more photons, an eavesdropper could measure its polarisation without disturbing the polarisation state of the remaining pulse. In this way, he can gain information about the key without introducing detectable errors. To protect against such attacks, the presented experiment employed the recently developed method of using additional 'decoy' states, i.e., the the intensity of the pulses created by the transmitter were varied in a random manner. By analysing the detection probabilities of the different pulses individually, a photon-number-splitting attack can be detected. Thanks to the decoy-state analysis, the secrecy of the resulting quantum key could be ensured despite the Poissonian nature of the emitted pulses. For a channel attenuation as high as 35 dB, a secret key rate of up to 250

Non-Coding RNAs: Multi-Tasking Molecules in the Cell

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Anita Quintal Gomes

2013-07-01

Full Text Available In the last years it has become increasingly clear that the mammalian transcriptome is highly complex and includes a large number of small non-coding RNAs (sncRNAs and long noncoding RNAs (lncRNAs. Here we review the biogenesis pathways of the three classes of sncRNAs, namely short interfering RNAs (siRNAs, microRNAs (miRNAs and PIWI-interacting RNAs (piRNAs. These ncRNAs have been extensively studied and are involved in pathways leading to specific gene silencing and the protection of genomes against virus and transposons, for example. Also, lncRNAs have emerged as pivotal molecules for the transcriptional and post-transcriptional regulation of gene expression which is supported by their tissue-specific expression patterns, subcellular distribution, and developmental regulation. Therefore, we also focus our attention on their role in differentiation and development. SncRNAs and lncRNAs play critical roles in defining DNA methylation patterns, as well as chromatin remodeling thus having a substantial effect in epigenetics. The identification of some overlaps in their biogenesis pathways and functional roles raises the hypothesis that these molecules play concerted functions in vivo, creating complex regulatory networks where cooperation with regulatory proteins is necessary. We also highlighted the implications of biogenesis and gene expression deregulation of sncRNAs and lncRNAs in human diseases like cancer.

Triple symmetric key cryptosystem for data security

Science.gov (United States)

Fuzail, C. Md; Norman, Jasmine; Mangayarkarasi, R.

2017-11-01

As the technology is getting spreads in the macro seconds of speed and in which the trend changing era from human to robotics the security issue is also getting increased. By means of using machine attacks it is very easy to break the cryptosystems in very less amount of time. Cryptosystem is a process which provides the security in all sorts of processes, communications and transactions to be done securely with the help of electronical mechanisms. Data is one such thing with the expanded implication and possible scraps over the collection of data to secure predominance and achievement, Information Security is the process where the information is protected from invalid and unverified accessibilities and data from mishandling. So the idea of Information Security has risen. Symmetric key which is also known as private key.Whereas the private key is mostly used to attain the confidentiality of data. It is a dynamic topic which can be implemented over different applications like android, wireless censor networks, etc. In this paper, a new mathematical manipulation algorithm along with Tea cryptosystem has been implemented and it can be used for the purpose of cryptography. The algorithm which we proposed is straightforward and more powerful and it will authenticate in harder way and also it will be very difficult to break by someone without knowing in depth about its internal mechanisms.

Double-valence-fluctuating molecules and superconductivity

International Nuclear Information System (INIS)

Hirsch, J.E.; Scalapino, D.J.

1985-01-01

We discuss the possibility of ''double-valence-fluctuating'' molecules, having two ground-state configurations differing by two electrons. We propose a possible realization of such a molecule, and experimental ways to look for it. We argue that a weakly coupled array of such molecules should give rise to a strong-coupling Shafroth-Blatt-Butler superconductor, with a high transition temperature

Study of the electronic properties of organic molecules within a metal-molecule-metal junction

International Nuclear Information System (INIS)

Lambert, Mathieu

2003-01-01

This ph-D thesis is about electronic transport through organic molecules inserted in a metal molecule-metal junction. We describe first a simple process to prepare sub-3 nm gaps by controllable breakage (under an electrical stress) of gold wires lithographed on a SiO 2 Si substrate at low temperature (4.2 K). We show that the involved mechanism is thermally assisted electromigration. We observe that current-voltage (I-V) characteristics of resulting electrodes are stable up to ∼5 V. which gives access to the well-known Fowler-Nordheim regime in the I-V, allowing an accurate characterisation of the gap size. The average gap is found lo be between 1.5 nm in width and 2.5 eV in height. Molecules and nanoparticles have then been inserted in the junction in the case of nanoparticles for example. The resulting IV clearly shows the suppression of electrical current at low bias known as Coulomb blockade. Characteristic of single-electron tunnelling through nanometer-sized structures, finally we fabricated a single-electron tunneling device based on Au nanoparticles connected to the electrodes via terthiophene (T3) molecule. We use the silicon substrate, separated from the planar structure by a silicon oxide of 200 nm, as an electrostatic gate and observed clear current modulation with possible signature of the transport properties of the terthiophene molecules. (author) [fr

Beneficial effects of bacteria-plant communication based on quorum sensing molecules of the N-acyl homoserine lactone group.

Science.gov (United States)

Schikora, Adam; Schenk, Sebastian T; Hartmann, Anton

2016-04-01

Bacterial quorum sensing (QS) mechanisms play a crucial role in the proper performance and ecological fitness of bacterial populations. Many key physiological processes are regulated in a QS-dependent manner by auto-inducers, like the N-acyl homoserine lactones (AHLs) in numerous Gram-negative bacteria. In addition, also the interaction between bacteria and eukaryotic hosts can be regulated by AHLs. Those mechanisms gained much attention, because of the positive effects of different AHL molecules on plants. This positive impact ranges from growth promotion to induced resistance and is quite contrasting to the rather negative effects observed in the interactions between bacterial AHL molecules and animals. Only very recently, we began to understand the molecular mechanisms underpinning plant responses to AHL molecules. In this review, we gathered the latest information in this research field. The first part gives an overview of the bacterial aspects of quorum sensing. Later we focus on the impact of AHLs on plant growth and AHL-priming, as one of the most understood phenomena in respect to the inter-kingdom interactions based on AHL-quorum sensing molecules. Finally, we discuss the potential benefits of the understanding of bacteria-plant interaction for the future agricultural applications.

Charting a Security Landscape in the Clouds: Data Protection and Collaboration in Cloud Storage

Science.gov (United States)

2016-07-01

strength of specific cryptographic primitives used such as Advanced Encryption Standard ( AES ); protection of keys and key materials beyond the protocol...Advanced Encryption Standard ( AES ) with a 256-bit key instead of a 128-bit key for example, is not a particularly insightful observation. Rather, this... AES Advanced Encryption Standard TLS/SSL Transport Layer Security/Security Socket Layer 35 REFERENCES [1] International Data Corporation

Spin tunneling in magnetic molecules

Science.gov (United States)

Kececioglu, Ersin

In this thesis, we will focus on spin tunneling in a family of systems called magnetic molecules such as Fe8 and Mn12. This is comparatively new, in relation to other tunneling problems. Many issues are not completely solved and/or understood yet. The magnetic molecule Fe 8 has been observed to have a rich pattern of degeneracies in its magnetic spectrum. We focus on these degeneracies from several points of view. We start with the simplest anisotropy Hamiltonian to describe the Fe 8 molecule and extend our discussion to include higher order anisotropy terms. We give analytical expressions as much as we can, for the degeneracies in the semi-classical limit in both cases. We reintroduce jump instantons to the instanton formalism. Finally, we discuss the effect of the environment on the molecule. Our results, for all different models and techniques, agree well with both experimental and numerical results.

Analysis of experimental positron-molecule binding energies

International Nuclear Information System (INIS)

Danielson, J R; Surko, C M; Young, J A

2010-01-01

Experiments show that positron annihilation on molecules frequently occurs via capture into vibrational Feshbach resonances. In these cases, the downshifts in the annihilation spectra from the vibrational mode spectra provide measures of the positron-molecule binding energies. An analysis of these binding energy data is presented in terms of the molecular dipole polarizability, the permanent dipole moment, and the number of π bonds in aromatic molecules. The results of this analysis are in reasonably good agreement with other information about positron-molecule bound states. Predictions for other targets and promising candidate molecules for further investigation are discussed.

Manet key management via Mobile Ficlke Key protocol (MFK ...

African Journals Online (AJOL)

Manet key management via Mobile Ficlke Key protocol (MFK) ... Journal of Fundamental and Applied Sciences. Journal Home · ABOUT THIS JOURNAL ... No Abstract. Keywords: MANET; key management scheme; simulation environment ...

Molecules cooled below the Doppler limit

Science.gov (United States)

Truppe, S.; Williams, H. J.; Hambach, M.; Caldwell, L.; Fitch, N. J.; Hinds, E. A.; Sauer, B. E.; Tarbutt, M. R.

2017-12-01

Magneto-optical trapping and sub-Doppler cooling have been essential to most experiments with quantum degenerate gases, optical lattices, atomic fountains and many other applications. A broad set of new applications await ultracold molecules, and the extension of laser cooling to molecules has begun. A magneto-optical trap (MOT) has been demonstrated for a single molecular species, SrF, but the sub-Doppler temperatures required for many applications have not yet been reached. Here we demonstrate a MOT of a second species, CaF, and we show how to cool these molecules to 50 μK, well below the Doppler limit, using a three-dimensional optical molasses. These ultracold molecules could be loaded into optical tweezers to trap arbitrary arrays for quantum simulation, launched into a molecular fountain for testing fundamental physics, and used to study collisions and chemistry between atoms and molecules at ultracold temperatures.

Cold atmospheric plasma (CAP changes gene expression of key molecules of the wound healing machinery and improves wound healing in vitro and in vivo.

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Stephanie Arndt

Full Text Available Cold atmospheric plasma (CAP has the potential to interact with tissue or cells leading to fast, painless and efficient disinfection and furthermore has positive effects on wound healing and tissue regeneration. For clinical implementation it is necessary to examine how CAP improves wound healing and which molecular changes occur after the CAP treatment. In the present study we used the second generation MicroPlaSter ß® in analogy to the current clinical standard (2 min treatment time in order to determine molecular changes induced by CAP using in vitro cell culture studies with human fibroblasts and an in vivo mouse skin wound healing model. Our in vitro analysis revealed that the CAP treatment induces the expression of important key genes crucial for the wound healing response like IL-6, IL-8, MCP-1, TGF-ß1, TGF-ß2, and promotes the production of collagen type I and alpha-SMA. Scratch wound healing assays showed improved cell migration, whereas cell proliferation analyzed by XTT method, and the apoptotic machinery analyzed by protein array technology, was not altered by CAP in dermal fibroblasts. An in vivo wound healing model confirmed that the CAP treatment affects above mentioned genes involved in wound healing, tissue injury and repair. Additionally, we observed that the CAP treatment improves wound healing in mice, no relevant side effects were detected. We suggest that improved wound healing might be due to the activation of a specified panel of cytokines and growth factors by CAP. In summary, our in vitro human and in vivo animal data suggest that the 2 min treatment with the MicroPlaSter ß® is an effective technique for activating wound healing relevant molecules in dermal fibroblasts leading to improved wound healing, whereas the mechanisms which contribute to these observed effects have to be further investigated.

OMG: Open Molecule Generator.

Science.gov (United States)

Peironcely, Julio E; Rojas-Chertó, Miguel; Fichera, Davide; Reijmers, Theo; Coulier, Leon; Faulon, Jean-Loup; Hankemeier, Thomas

2012-09-17

Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG), which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck.

OMG: Open Molecule Generator

Directory of Open Access Journals (Sweden)

Peironcely Julio E

2012-09-01

Full Text Available Abstract Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG, which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck.

Key processes at the stand to landscape scale

International Nuclear Information System (INIS)

Perry, D.A.

1991-01-01

The smooth transition from one mature community type to another during climate change depends on the rate of climate change, the speed of migration, and the stability of extant communities as they become increasingly maladapted to local climates. The expected increase in natural disturbances will probably be the most important factor influencing forests over the next century, and has the potential to convert many forests to early successional, perhaps weedy vegetation. Protecting key structures and processes at both the stand and landscape scale will be critically important to easing the transition from one mature forest type to another and preventing site capture by weeds. Two general steps are necessary at the landscape scale: maintain migration corridors, and promote landscape patterns that dampen, rather than magnify, the spread of disturbances. At the stand level, it will be important to protect photosynthetic capacity and soil fertility. Steps to accomplish these goals include: protection of habitats required by natural enemies of forest pests; maintenance or restoration of natural biological diversity; maintenance or restoration of individual tree vigor through practices such as aggressive thinning; and moving from clearcutting to shelterwoods and/or group selections, thereby keeping some cover of mature green trees on sites at all times. 28 refs

Microencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery.

Science.gov (United States)

Li, Xiang; Anton, Nicolas; Ta, Thi Minh Chau; Zhao, Minjie; Messaddeq, Nadia; Vandamme, Thierry F

2011-01-01

Nanoemulsions consist of very stable nanodroplets of oil dispersed in an aqueous phase, typically below 300 nm in size. They can be used to obtain a very fine, homogeneous dispersion of lipophilic compounds in water, thus facilitating their handling and use in nanomedicine. However, the drawback is that they are suspended in an aqueous media. This study proposes a novel technique for drying lipid nanoemulsion suspensions to create so-called Trojan particles, ie, polymer microparticles (around 2 μm) which very homogeneously "entrap" the nano-oil droplets (around 150 nm) in their core. Microencapsulation of the nanoemulsions was performed using a spray-drying process and resulted in a dried powder of microparticles. By using a low-energy nanoemulsification method and relatively gentle spray-drying, the process was well suited to sensitive molecules. The model lipophilic molecule tested was vitamin E acetate, encapsulated at around 20% in dried powder. We showed that the presence of nanoemulsions in solution before spray-drying had a significant impact on microparticle size, distribution, and morphology. However, the process itself did not destroy the oil nanodroplets, which could easily be redispersed when the powder was put back in contact with water. High-performance liquid chromatography follow-up of the integrity of the vitamin E acetate showed that the molecules were intact throughout the process, as well as when conserved in their dried form. This study proposes a novel technique using a spray-drying process to microencapsulate nanoemulsions. The multiscale object formed, so-called Trojan microparticles, were shown to successfully encapsulate, protect, and release the lipid nanodroplets.

Physics of Complex Polymeric Molecules

Science.gov (United States)

Kelly, Joshua Walter

The statistical physics of complex polymers with branches and circuits is the topic of this dissertation. An important motivation are large, single-stranded (ss) RNA molecules. Such molecules form complex ``secondary" and ``tertiary" structures that can be represented as branched polymers with circuits. Such structures are in part directly determined by the nucleotide sequence and in part subject to thermal fluctuations. The polymer physics literature on molecules in this class has mostly focused on randomly branched polymers without circuits while there has been minimal research on polymers with specific structures and on polymers that contain circuits. The dissertation is composed of three parts: Part I studies branched polymers with thermally fluctuating structure confined to a potential well as a simple model for the encapsidation of viral RNA. Excluded volume interactions were ignored. In Part II, I apply Flory theory to the study of the encapsidation of viral ss RNA molecules with specific branched structures, but without circuits, in the presence of excluded volume interaction. In Part III, I expand on Part II and consider complex polymers with specific structure including both branching and circuits. I introduce a method based on the mathematics of Laplacian matrices that allows me to calculate density profiles for such molecules, which was not possible within Flory theory.

CHILDREN'S HEALTH PROTECTION IN INTERSECTORAL CONNECTION

Directory of Open Access Journals (Sweden)

Yu.E. Lapin

2008-01-01

Full Text Available Recently discovered phenomenon of compensatory mechanism of absence of legislative durable national policy in health protection of children is described in this article. This mechanism was developed as a result of evolution of intersect oral connection for the sake of children's health protection. «National family policy», «national policy for the sake of children», «national policy in the field of circulation of narcotic, psychotropic substances and in the field of counteraction to its illegal use», «national policy of Russian federation in the field of education», «national policy in the field of labor relations» perform functions of such compensatory mechanism. Fact of regulation of social relations in the sphere of children's health protection with means of different active directions of national policy is evidence of legal assignment of a number of problems in children's health protection as real subject of policy. The negative feature of this problem is incomplete and fragmentary regulation of relationships in the field of children's health protection. This is the reason, which maintains a status of children's health protection service as passive dirigible object but not an active regulative factor.Key words: children, health, national policy.

Protection Mode of Key Customer Cable and Typical Application%大客户光缆保护方式探讨及典型应用

Institute of Scientific and Technical Information of China (English)

李光

2016-01-01

Due to the interference of outside factors, the optical cable of key customers is often damaged or the communication is interfered, which not only affect the customer's business activities, but also challenges the cable communication service quality of communication company. In this paper, based on this problem, several common metropolitan area network optical cable transmission physical double routing protection methods are discussed. Finally the 1/2 branching device, 1í2 optical switch and CWDM mutual protection transmission is selected, and its feasibility is verified through typical applications.%因外力因素的干扰，大客户光缆线在运行中常常遭到破坏或通信受到干扰，不仅对客户的业务活动造成影响，而且对于通信公司光缆通信服务质量也是一种挑战。本文基于这一问题，通过对目前几种主流的城域网光缆传输物理双路由保护方式进行分析探讨，最终选定1/2分路器、1×2光开关和CWDM组成的互保传输方式，继而通过典型应用验证其可行性。

Study of radionuclides speciation with biological molecules of interest by spectrometric techniques

International Nuclear Information System (INIS)

Lourenco, V.

2007-07-01

Mechanisms of complexation and accumulation of the radionuclides at the cellular and molecular level are complex and poorly known because the studies on these subjects are scarce. Within the framework of this thesis, we studied the interactions of europium (analogue of trivalent actinides) and uranium (VI) (actinide) with biological molecules of interest: phyto-chelatins. Their role is to protect cells against intrusions from nonessential heavy metals (thus toxic). These proteins are likely to be implied in the mechanisms of sequestration of radionuclides in living organisms. However, their structure is complex, this is why, in order to better understand their reactivity, we extended our studies to lower entities which constitute them (amino acids and glutathione). We determined solution speciation (stoichiometry, structure) as well as the complexing constants associated with the formation of these species. These studies were undertaken by Time Resolved Laser induced Fluorescence (TRLIF), Electro-Spray Mass Spectrometry (ES-MS), Nuclear Magnetic Resonance (NMR), Fourier Transform Infra-Rouge spectroscopy (FTIR) and Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS). The determination of the complexation constants enabled us to conclude that the complexing capacity of these molecules with respect to radionuclides was moderate (log 10 K 1 < 3, pH 3 or 6), the formed species are mononuclear with only one ligand molecule (1:1). The interaction is performed via oxygenated (hard) groups. The direct complexation of europium with phyto-chelatins at acidic pH was studied jointly by TRLIF and ES-MS. The complexing capacity of these molecules is much higher than that of GSH from which they result. In addition to studies undertaken on synthetic solutions reproducing the 'biological' conditions (pH close to neutrality, ionic strength 0.1 mol/L, etc), tests of cellular contamination were realized. The quantification of integrated europium showed that those are able to

Single Molecule Spectroscopy of Electron Transfer

International Nuclear Information System (INIS)

Holman, Michael; Zang, Ling; Liu, Ruchuan; Adams, David M.

2009-01-01

The objectives of this research are threefold: (1) to develop methods for the study electron transfer processes at the single molecule level, (2) to develop a series of modifiable and structurally well defined molecular and nanoparticle systems suitable for detailed single molecule/particle and bulk spectroscopic investigation, (3) to relate experiment to theory in order to elucidate the dependence of electron transfer processes on molecular and electronic structure, coupling and reorganization energies. We have begun the systematic development of single molecule spectroscopy (SMS) of electron transfer and summaries of recent studies are shown. There is a tremendous need for experiments designed to probe the discrete electronic and molecular dynamic fluctuations of single molecules near electrodes and at nanoparticle surfaces. Single molecule spectroscopy (SMS) has emerged as a powerful method to measure properties of individual molecules which would normally be obscured in ensemble-averaged measurement. Fluctuations in the fluorescence time trajectories contain detailed molecular level statistical and dynamical information of the system. The full distribution of a molecular property is revealed in the stochastic fluctuations, giving information about the range of possible behaviors that lead to the ensemble average. In the case of electron transfer, this level of understanding is particularly important to the field of molecular and nanoscale electronics: from a device-design standpoint, understanding and controlling this picture of the overall range of possible behaviors will likely prove to be as important as designing ia the ideal behavior of any given molecule.

Alternative types of molecule-decorated atomic chains in Au–CO–Au single-molecule junctions

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Zoltán Balogh

2015-06-01

Full Text Available We investigate the formation and evolution of Au–CO single-molecule break junctions. The conductance histogram exhibits two distinct molecular configurations, which are further investigated by a combined statistical analysis. According to conditional histogram and correlation analysis these molecular configurations show strong anticorrelations with each other and with pure Au monoatomic junctions and atomic chains. We identify molecular precursor configurations with somewhat higher conductance, which are formed prior to single-molecule junctions. According to detailed length analysis two distinct types of molecule-affected chain-formation processes are observed, and we compare these results to former theoretical calculations considering bridge- and atop-type molecular configurations where the latter has reduced conductance due to destructive Fano interference.

ICRP Publication 138: Ethical Foundations of the System of Radiological Protection.

Science.gov (United States)

Cho, K-W; Cantone, M-C; Kurihara-Saio, C; Le Guen, B; Martinez, N; Oughton, D; Schneider, T; Toohey, R; ZöLzer, F

2018-02-01

Despite a longstanding recognition that radiological protection is not only a matter of science, but also ethics, ICRP publications have rarely addressed the ethical foundations of the system of radiological protection explicitly. The purpose of this publication is to describe how the Commission has relied on ethical values, either intentionally or indirectly, in developing the system of radiological protection with the objective of presenting a coherent view of how ethics is part of this system. In so doing, it helps to clarify the inherent value judgements made in achieving the aim of the radiological protection system as underlined by the Commission in Publication 103. Although primarily addressed to the radiological protection community, this publication is also intended to address authorities, operators, workers, medical professionals, patients, the public, and its representatives (e.g. NGOs) acting in the interest of the protection of people and the environment. This publication provides the key steps concerning the scientific, ethical, and practical evolutions of the system of radiological protection since the first ICRP publication in 1928. It then describes the four core ethical values underpinning the present system: beneficence/ non-maleficence, prudence, justice, and dignity. It also discusses how these core ethical values relate to the principles of radiological protection, namely justification, optimisation, and limitation. The publication finally addresses key procedural values that are required for the practical implementation of the system, focusing on accountability, transparency, and inclusiveness. The Commission sees this publication as a founding document to be elaborated further in different situations and circumstances.