688 research outputs found

    From neural-based object recognition toward microelectronic eyes

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    Engineering neural network systems are best known for their abilities to adapt to the changing characteristics of the surrounding environment by adjusting system parameter values during the learning process. Rapid advances in analog current-mode design techniques have made possible the implementation of major neural network functions in custom VLSI chips. An electrically programmable analog synapse cell with large dynamic range can be realized in a compact silicon area. New designs of the synapse cells, neurons, and analog processor are presented. A synapse cell based on Gilbert multiplier structure can perform the linear multiplication for back-propagation networks. A double differential-pair synapse cell can perform the Gaussian function for radial-basis network. The synapse cells can be biased in the strong inversion region for high-speed operation or biased in the subthreshold region for low-power operation. The voltage gain of the sigmoid-function neurons is externally adjustable which greatly facilitates the search of optimal solutions in certain networks. Various building blocks can be intelligently connected to form useful industrial applications. Efficient data communication is a key system-level design issue for large-scale networks. We also present analog neural processors based on perceptron architecture and Hopfield network for communication applications. Biologically inspired neural networks have played an important role towards the creation of powerful intelligent machines. Accuracy, limitations, and prospects of analog current-mode design of the biologically inspired vision processing chips and cellular neural network chips are key design issues

    Reliability of Community Health Worker Collected Data for Planning and Policy in a Peri-Urban Area of Kisumu, Kenya

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    A general introduction of this article is as follows: Reliable and timely health information is an essential foundation of public health action and health systems strengthening, both nationally and internationally (Aqil et al. in Health Policy Plan 24(3): 217–228, 2009; Bradshaw et al. in initial burden of disease estimates for South Africa, 2000. South African Medical Research Council, Cape Town, 2003). The need for sound information is especially urgent in the case of emergent diseases and other acute health threats, where rapid awareness, investigation and response can save lives and prevent broader national outbreaks and even global pandemics (Aqil et al. in Health Policy Plan 24(3): 217–228, 2009). The government of Kenya, through the ministry of public health and sanitation has rolled out the community health strategy as a way of improving health care at the household level. This involves community health workers collecting health status data at the household level, which is then used for dialogue at all the levels to inform decisions and actions towards improvement in health status. A lot of health interventions have involved the community health workers in reaching out to the community, hence successfully implementing these health interventions. Large scale involvement of community health workers in government initiatives and most especially to collect health data for use in the health systems has been minimal due to the assumption that the data may not be useful to the government, because its quality is uncertain. It was therefore necessary that the validity and reliability of the data collected by community health workers be determined, and whether this kind of data can be used for planning and policy formulation for the communities from which it is collected. This would go a long way to settle speculation on whether the data collected by these workers is valid and reliable for use in determining the health status, its causes and distribution, of a community. Our general objective of this article is to investigate the validity and reliability of Community Based Information, and we deal with research question “What is the reliability of data collected at the Community level by Community health workers?”. The methods which we use to find an reliable answer to this question is “Ten percent of all households visited by CHWs for data collection were recollected by a technically trained team. Test/retest method was applied to the data to establish reliability. The Kappa score, sensitivity, specificity and positive predictive values were also used to measure reliability”. Finally our findings are as follows: Latrine availability and Antenatal care presented good correspondence between the two sets of data. This was also true for exclusive breast feeding indicator. Measles immunization coverage showed less consistency than the rest of the child health indicators. At last we conclude and recommend that CHWs can accurately and reliably collect household data which can be used for health decisions and actions especially in resource poor settings where other approaches to population based data are too expensive

    Acute adrenal crisis after orthopedic surgery for pathologic fracture

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    BACKGROUND: Adrenal crisis after surgical procedure is a rare but potentially catastrophic life-threatening event. Its manifestations, such as hypotension, tachycardia, hypoxia, and fever mimic the other more common postoperative complications. Clinical outcome is dependent upon early recognition of the condition and proper management with exogenous steroid administration. CASE PRESENTATION: We report a 75-year-old man who presented with shock immediately after surgery for a femoral fracture from lung cancer metastasis. Anemia and severe hyponatremia were detected. Despite adequate fluid resuscitation, nonspecific symptoms including hypotension, tachycardia, hypoxia, fever and confusion occurred. Emergent CT revealed enlarged bilateral adrenal glands. Under the diagnosis of adrenal crisis due to metastatic infiltration of adrenal glands, the patient was treated with appropriate steroid replacement resulting in rapid improvement and recovery. CONCLUSION: We describe a case of adrenal crisis caused by the lack of adrenal reserve based on metastatic involvement and surgical stress, the first published case of adrenal crisis after surgery for a pathologic fracture from lung cancer metastasis. Surgeons treating pathologic fractures should be aware of this complication and familiar with its appropriate therapy because of increasing opportunity to care patients with metastatic bone tumors due to recent advances in cancer treatment

    Analysis of Scientific Papers Included in the

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    Background The purpose of our study was to analyze scientific papers published by SouthKorean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE),and to evaluate the publication and research activities of Korean plastic surgeon.Methods We conducted a survey of SCIE papers in the field of plastic surgery published bySouth Korean authors between 2001 and 2010 using Web of Science software. We furtheranalyzed these results according to the number of publications per year, journals, institution,and type of papers. We also compared the total number of citations to published scientificpapers. We analyzed the rank of South Korea among other countries in representative journals.Results Overall, 667 papers were published by South Korean authors between 2001 and 2010.The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139).Subsequently, the ten most productive Korean medical colleges were identified. All publishedpapers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Koreaamong other countries in terms of the number of published papers remained in the top 10during the recent 10 years.Conclusions Publication output of Korean plastic surgeon over the last 10 years showed aremarkable growth in terms of quantity and quality. Currently, Korea is among the top sixcountries in representative plastic surgery journals. Korean plastic surgeons have playeda central role in this progress, and it is anticipated that they will continue to do so in thefuture

    Analysis of Scientific Papers Included in the Sciences Citation Index Expanded Written by South Korean Plastic Surgeons: 2001-2010

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    BackgroundThe purpose of our study was to analyze scientific papers published by South Korean plastic surgeons in journals included in the Science Citation Index Expanded (SCIE), and to evaluate the publication and research activities of Korean plastic surgeon.MethodsWe conducted a survey of SCIE papers in the field of plastic surgery published by South Korean authors between 2001 and 2010 using Web of Science software. We further analyzed these results according to the number of publications per year, journals, institution, and type of papers. We also compared the total number of citations to published scientific papers. We analyzed the rank of South Korea among other countries in representative journals.ResultsOverall, 667 papers were published by South Korean authors between 2001 and 2010. The number of publications increased dramatically from 2003 (n=31) to 2010 (n=139). Subsequently, the ten most productive Korean medical colleges were identified. All published papers received 2,311 citations and the citation to paper ratio was 3.49. The rank of Korea among other countries in terms of the number of published papers remained in the top 10 during the recent 10 years.ConclusionsPublication output of Korean plastic surgeon over the last 10 years showed a remarkable growth in terms of quantity and quality. Currently, Korea is among the top six countries in representative plastic surgery journals. Korean plastic surgeons have played a central role in this progress, and it is anticipated that they will continue to do so in the future

    Simulations of events for the LUX-ZEPLIN (LZ) dark matter experiment

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    The LUX-ZEPLIN dark matter search aims to achieve a sensitivity to the WIMP-nucleon spin-independent cross-section down to (1–2)×10−12 pb at a WIMP mass of 40 GeV/c2. This paper describes the simulations framework that, along with radioactivity measurements, was used to support this projection, and also to provide mock data for validating reconstruction and analysis software. Of particular note are the event generators, which allow us to model the background radiation, and the detector response physics used in the production of raw signals, which can be converted into digitized waveforms similar to data from the operational detector. Inclusion of the detector response allows us to process simulated data using the same analysis routines as developed to process the experimental data

    Direct immobilization of DNA probes on non-modified plastics by UV irradiation and integration in microfluidic devices for rapid bioassay

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    DNA microarrays have become one of the most powerful tools in the field of genomics and medical diagnosis. Recently, there has been increased interest in combining microfluidics with microarrays since this approach offers advantages in terms of portability, reduced analysis time, low consumption of reagents, and increased system integration. Polymers are widely used for microfluidic systems, but fabrication of microarrays on such materials often requires complicated chemical surface modifications, which hinders the integration of microarrays into microfluidic systems. In this paper, we demonstrate that simple UV irradiation can be used to directly immobilize poly(T)poly(C)-tagged DNA oligonucleotide probes on many different types of plastics without any surface modification. On average, five- and fourfold improvement in immobilization and hybridization efficiency have been achieved compared to surface-modified slides with aminated DNA probes. Moreover, the TC tag only costs 30% of the commonly used amino group modifications. Using this microarray fabrication technique, a portable cyclic olefin copolymer biochip containing eight individually addressable microfluidic channels was developed and used for rapid and parallel identification of Avian Influenza Virus by DNA hybridization. The one-step, cost-effective DNA-linking method on non-modified polymers significantly simplifies microarray fabrication procedures and permits great flexibility to plastic material selection, thus making it convenient to integrate microarrays into plastic microfluidic systems

    OmpR controls Yersinia enterocolitica motility by positive regulation of flhDC expression

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    Flagella and invasin play important roles during the early stages of infection by the enteric pathogen Yersinia enterocolitica. Our previous study demonstrated that OmpR negatively regulates invasin gene expression at the transcriptional level. The present study focused on the role of OmpR in the regulation of flagella expression. Motility assays and microscopic observations revealed that an ompR mutant strain exhibits a non-motile phenotype due to the lack of flagella. An analysis of flhDC::lacZYA chromosomal fusions demonstrated a decrease in flhDC expression in ompR mutant cells, suggesting a role for OmpR in the positive control of flagellar master operon flhDC, which is in contrast to the negative role it plays in Escherichia coli. Moreover, high temperature or osmolarity and low pH decreased flhDC expression and OmpR was not required for the response to these factors. Evidence from an examination of the DNA binding properties of OmpR in vitro indicated that the mechanism by which OmpR regulates flhDC is direct. Electrophoretic mobility shift assays confirmed that OmpR binds specifically to the flhDC promoter region and suggested the presence of more than one OmpR-binding site. In addition, phosphorylation of OmpR by acetyl-P appeared to stimulate the binding abilities of OmpR. Together with the results of our previous studies revealing the negative role of OmpR in the regulation of invasin expression, these findings support a model in which invasion and motility might be reciprocally regulated by OmpR

    Mesenchymal Stem Cells Induce T-Cell Tolerance and Protect the Preterm Brain after Global Hypoxia-Ischemia

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    Hypoxic-ischemic encephalopathy (HIE) in preterm infants is a severe disease for which no curative treatment is available. Cerebral inflammation and invasion of activated peripheral immune cells have been shown to play a pivotal role in the etiology of white matter injury, which is the clinical hallmark of HIE in preterm infants. The objective of this study was to assess the neuroprotective and anti-inflammatory effects of intravenously delivered mesenchymal stem cells (MSC) in an ovine model of HIE. In this translational animal model, global hypoxia-ischemia (HI) was induced in instrumented preterm sheep by transient umbilical cord occlusion, which closely mimics the clinical insult. Intravenous administration of 2 x 106MSC/kg reduced microglial proliferation, diminished loss of oligodendrocytes and reduced demyelination, as determined by histology and Diffusion Tensor Imaging (DTI), in the preterm brain after global HI. These anti-inflammatory and neuroprotective effects of MSC were paralleled by reduced electrographic seizure activity in the ischemic preterm brain. Furthermore, we showed that MSC induced persistent peripheral T-cell tolerance in vivo and reduced invasion of T-cells into the preterm brain following global HI. These findings show in a preclinical animal model that intravenously administered MSC reduced cerebral inflammation, protected against white matter injury and established functional improvement in the preterm brain following global HI. Moreover, we provide evidence that induction of T-cell tolerance by MSC might play an important role in the neuroprotective effects of MSC in HIE. This is the first study to describe a marked neuroprotective effect of MSC in a translational animal model of HIE
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