Supersequences of masks for oligo-chips

On a very small surface, a chip, several thousands of oligonucleotides, can be synthesized using a mask technology. Given a set of oligos, the problems tackled here are: What is the minimum number of masks necessary to synthesize one copy of each oligo? How long will be the series of masks if each oligo is synthesized twice, such that the two copies are realized with two completely different series of masks? We establish that, for 20,000 oligos of 20 bases a single copy can be synthesized with around 67 masks and for two copies with less than the double.     

宏基因组学技术在痤疮研究中的应用进展

高通量测序技术的发展提高了人们对微生物组的认识。宏基因组学技术因其全面和深入的分析功能被广泛应用于各种环境微生物组的研究中,尤其在阐明各种疾病与人体微生物组的关系中,宏基因组学技术具有重要作用。痤疮作为一种常见的皮肤疾病,严重影响人们皮肤美观度和心理健康。利用宏基因组学技术挖掘皮肤微生物与痤疮的关系,将有助于痤疮发病机理的研究和临床治疗方法的改进。通过介绍宏基因组学技术的发展背景、概述及其应用研究进展,探讨皮肤微生物与痤疮的关系,综述宏基因组学技术在痤疮研究中的应用现状,并总结目前宏基因组学技术在皮肤疾病研究中存在的问题,旨在为痤疮的宏基因组研究提供参考。     

Education for science and science for education: more than a play upon words

In the celebration of the Oswaldo Cruz Institute centenary, we wanted to stress our concern with the relationship between two of its missions: research and education. What are the educational bases required for science and technology activities on health sciences for the future years? How can scientists collaborate to promote the popularization of academic knowledge and to improve a basic education for citizenship in an ethic and humanistic view? In this article we pointed out to need of commitment, even in the biomedical post-graduation level, of a more integrated philosophy that would be centered on health education, assuming health as a dynamic biological and social equilibrium and emphasizing the need of scientific popularization of science in a cooperative construction way, instead of direct transfer of knowledge, preserving also macro views of health problems in the development of very specific studies. The contemporary explosion of knowledge, particularly biological knowledge, imposes a need of continuous education to face the growing illiteracy. In order to face this challenge, we think that the Oswaldo Cruz Institute honors his dialectic profile of tradition and transformation, always creating new perspectives to disseminate scientific culture in innovator forms.     

Percussive technology in human evolution: an introduction to a comparative approach in fossil and living primates

Percussive technology is part of the behavioural suite of several fossil and living primates. Stone Age ancestors used lithic artefacts in pounding activities, which could have been most important in the earliest stages of stone working. This has relevant evolutionary implications, as other primates such as chimpanzees and some monkeys use stone hammer-and-anvil combinations to crack hard-shelled foodstuffs. Parallels between primate percussive technologies and early archaeological sites need to be further explored in order to assess the emergence of technological behaviour in our evolutionary line, and firmly establish bridges between Primatology and Archaeology. What are the anatomical, cognitive and ecological constraints of percussive technology? How common are percussive activities in the Stone Age and among living primates? What is their functional significance? How similar are archaeological percussive tools and those made by non-human primates? This issue of Phil. Trans. addresses some of these questions by presenting case studies with a wide chronological, geographical and disciplinary coverage. The studies presented here cover studies of Brazilian capuchins, captive chimpanzees and chimpanzees in the wild, research on the use of percussive technology among modern humans and recent hunter–gatherers in Australia, the Near East and Europe, and archaeological examples of this behaviour from a million years ago to the Holocene. In summary, the breadth and depth of research compiled here should make this issue of Philosophical Transactions of the Royal Society B, a landmark step forward towards a better understanding of percussive technology, a unique behaviour shared by some modern and fossil primates.     

Development of a Fischer-Tropsch catalyst: From laboratory to commercial scale demonstration

This paper deals with the study, the development and the optimization of a proprietary Fischer-Tropsch process, performed by ENI in cooperation with Institut Fran?ais du Pétrole and Axens, for the transformation of natural gas into liquid fuels. The current carbon scenario and the future forecasts have brought on a renewed interest of the oil companies for this old technology: an overview of the oil and gas reserves underlines the necessity of gas valorisation, and the main GTL projects currently performed around the world are presented. Fischer-Tropsch synthesis details and the catalyst design strategy followed by ENI are also discussed, with specific attention on the problems that are usual met when moving from the laboratory to the industrial and commercial scale.

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Riassunto   Sviluppo di un catalizzatore Fischer-Tropsch: dalla scala di laboratorio all'impianto dimostrativo in dustriale. Eni, in collaborazione con l'Institut Fran?ais du Pétrole e Axens ha messo a punto un processo Fischer-Tropsch proprietario per la trasformazione di gas naturale in combustibile liquido. L'attuale situazione internazionale e le proiezioni future sull'abbondanza e la disponibilità del petrolio hanno portato ad un rinnovato interesse da parte delle maggiori compagnie petrolifere verso questa ?vecchia? tecnologia. La valutazione delle riserve di olio e di gas mette in evidenza, infatti, la necessità di una valorizzazione del gas naturale e nell'articolo vengono presentati i principali progetti GtL attualmente in fase di realizzazione nel mondo. Viene poi descritta la strategia adottata da Eni/IFP-Axens per lo sviluppo e l'ottimizzazione del catalizzatore e del processo, sottolineando in particolare i problemi che usualmente si incontrano passando dalla scala di laboratorio all'impianto dimostrativo industriale.

     

北京市双向转诊信息化模式研究

针对北京市双向转诊的3种典型模式，通过现场调研分析不同的双向转诊信息化实现模式在实施过程中的现状、经验和存在的问题，为双向转诊的实施提供技术支撑工作，为提高双向转诊信息化建设水平和质量提出相应的政策建议，从而提高医疗资源利用效率和水平。     

Fitting curves to data using nonlinear regression: a practical and nonmathematical review

Many types of data are best analyzed by fitting a curve using nonlinear regression, and computer programs that perform these calculations are readily available. Like every scientific technique, however, a nonlinear regression program can produce misleading results when used inappropriately. This article reviews the use of nonlinear regression in a practical and nonmathematical manner to answer the following questions: Why is nonlinear regression superior to linear regression of transformed data? How does nonlinear regression differ from polynomial regression and cubic spline? How do nonlinear regression programs work? What choices must an investigator make before performing nonlinear regression? What do the final results mean? How can two sets of data or two fits to one set of data be compared? What problems can cause the results to be wrong? This review is designed to demystify nonlinear regression so that both its power and its limitations will be appreciated.     

Cell wall proteins: a new insight through proteomics

Cell wall proteins are essential constituents of plant cell walls; they are involved in modifications of cell wall components, wall structure, signaling and interactions with plasma membrane proteins at the cell surface. The application of proteomic approaches to the cell wall compartment raises important questions: are there technical problems specific to cell wall proteomics? What kinds of proteins can be found in Arabidopsis walls? Are some of them unexpected? What sort of post-translational modifications have been characterized in cell wall proteins to date? The purpose of this review is to discuss the experimental results obtained to date using proteomics, as well as some of the new questions challenging future research.     

Promise and progress in environmental genomics: a status report on the applications of gene expression-based microarray studies in ecologically relevant fish species

The advent of any new technology is typically met with great excitement. So it was a few years ago, when the combination of advances in sequencing technology and the development of microarray technology made measurements of global gene expression in ecologically relevant species possible. Many of the review papers published around that time promised that these new technologies would revolutionize environmental biology as they had revolutionized medicine and related fields. A few years have passed since these technological advancements have been made, and the use of microarray studies in non‐model fish species has been adopted in many laboratories internationally. Has the relatively widespread adoption of this technology really revolutionized the fields of environmental biology, including ecotoxicology, aquaculture and ecology, as promised? Or have these studies merely become a novelty and a potential distraction for scientists addressing environmentally relevant questions? In this review, the promises made in early review papers, in particular about the advances that the use of microarrays would enable, are summarized; these claims are compared to the results of recent studies to determine whether the forecasted changes have materialized. Some applications, as discussed in the paper, have been realized and have led to advances in their field, others are still under development.     

Implementing biofuels on a global scale

Is the introduction of renewable biofuels a simple problem of technology development and diffusion or does it require an industrial revolution?     

On a stochastic version of a modified Nicholson-Baily model

‘Deterministic’ models in population dynamics often are really approximations to stochastic models, justified by an appeal to ‘the law of large numbers’. It is proposed to call such models ‘pseudodeterministic’. Four questions are discussed in this article: (1) What errors may be made by equating deterministically predicted values to expectations? (2) When, and in what sense, may numbers be assumed to be large? (3) How large are the variances, coefficients of variations, etc., as assigned to the variables in the stochastic versions of the models? (4) What role may pseudodeterministic models play in empirical research, where problems of statistical reliability arise? As an example, a modified Nicholson-Bailey model of the interaction between insect parasitoids and their hosts is discussed; the modification consists of assigning a random (density-independent) mortality to the parasitoid population. A stochastic version of this model is discussed. The expectation of the final host density is compared with the value computed from the deterministic model. The latter value is systematically lower than the former. The magnitude of the difference depends on parameter values. The variability to be expected with the stochastic model is characterized by the coefficient of variation of the final host density; its dependence on parameter values and initial conditions is discussed. It is concluded that it is worthwhile in practical applications to estimate parasitoid mortality, and that the coefficient of variation in real situations may be far from negligible.     

Next-generation sequencing applications for wheat crop improvement

? Bread wheat (Triticum aestivum; Poaceae) is a crop plant of great importance. It provides nearly 20% of the world's daily food supply measured by calorie intake, similar to that provided by rice. The yield of wheat has doubled over the last 40 years due to a combination of advanced agronomic practice and improved germplasm through selective breeding. More recently, yield growth has been less dramatic, and a significant improvement in wheat production will be required if demand from the growing human population is to be met. ? Next-generation sequencing (NGS) technologies are revolutionizing biology and can be applied to address critical issues in plant biology. Technologies can produce draft sequences of genomes with a significant reduction to the cost and timeframe of traditional technologies. In addition, NGS technologies can be used to assess gene structure and expression, and importantly, to identify heritable genome variation underlying important agronomic traits. ? This review provides an overview of the wheat genome and NGS technologies, details some of the problems in applying NGS technology to wheat, and describes how NGS technologies are starting to impact wheat crop improvement.     

A rotary pumping model for helicase function of MCM proteins at a distance from replication forks

We propose an integrated model for eukaryotic DNA replication to explain the following problems: (1) How is DNA spooled through fixed sites of replication? (2) What and where are the helicases that unwind replicating DNA? (3) Why are the best candidates for replicative helicases, namely mini-chromosome maintenance (MCM) proteins, not concentrated at the replication fork? (4) How do MCM proteins spread away from loading sites at origins of replication? We draw on recent discoveries to argue that the MCM hexameric ring is a rotary motor that pumps DNA along its helical axis by simple rotation, such that the movement resembles that of a threaded bolt through a nut, and we propose that MCM proteins act at a distance from the replication fork to unwind DNA. This model would place DNA replication in a growing list of processes, such as recombination and virus packaging, that are mediated by ring-shaped ATPases pumping DNA by helical rotation.     

Do Birds of a Feather Flock Together?

Cooperation requires that individuals are able to identify, and preferentially associate with, others who have compatible preferences and the shared background knowledge needed to solve interpersonal coordination problems. The present study investigates the nature of such similarity within social networks, asking: What do friends have in common? And what is the relationship between similarity and altruism? The results show that similarity declines with frequency of contact; similarity in general is a significant predictor of altruism and emotional closeness; and, specifically, sharing a sense of humor, hobbies and interests, moral beliefs, and being from the same area are the best predictors. These results shed light on the structure of relationships within networks and provide a possible checklist for predicting attitudes toward strangers, and in-group identification.     

Phytoremediation: green technology for the removal of mixed contaminants of a water supply reservoir

The Iraí Reservoir, a water supply in Brazil, is constantly impacted by anthropogenic activities such as waste inputs from agriculture, hospitals and urbanization, resulting toxic cyanobacterial blooms causing economic, social and environmental problems. This study assessed the concentration of some common contaminants of the Iraí Reservoir, namely paracetamol, diclofenac and microcystin-LR and tested whether a laboratory scale Green Liver System^® would serve as a suitable technology to remove these contaminants. Further, the study investigated whether the pollutants caused adverse effects to the macrophytes using catalase as a biomarker for oxidative stress and investigated whether biotransformation (glutathione S-transferase) was a main route for detoxification. Egeria densa, Ceratophyllum demersum and Myriophyllum aquaticum were exposed to a mixture of the three contaminants for 14?days in a concentration range similar to those detected in the reservoir. The plants removed 93% of diclofenac and 100% of MC-LR after 14?days. Paracetamol could not be detected. Catalase and glutathione S-transferase enzyme activities remained unaltered after the 14-day exposure, indicating that the mixture did not cause oxidative stress. The study showed that the aquatic macrophytes used are suitable tools to apply in a Green Liver System^® for the remediation of mixed pollutants.     

Copper Concentration in a Healthy Urban Adult Population of Southern Iran

Nutritional deficiencies are important and widespread problems in most developing countries. Preventing and correcting micronutrient deficiencies are important because of the multiple negative consequences of these deficiencies. This study was designed to determine the prevalence of copper deficiency in an adult population in Shiraz, southern Iran. We also determined the association between copper status and other factors such as age, sex, and body mass index (BMI). In this cross-sectional study, 416 adults residing in Shiraz were selected by two-stage sampling. Serum copper was measured by flame-atomic absorption spectrometry. The data were analyzed with SPSS software. Mean age in our sample was 39.33?±?15.06 years, and mean BMI was 26.17?±?4.81 kg/m(2). Mean serum copper concentration was 118.15?±?54.33 μg/dL in the whole sample, 109.74?±?56.22 μg/dL in men, and 122.15?±?53.04 μg/dL in women. The overall prevalence of copper deficiency was 24%. The prevalence of copper deficiency differed significantly between men and women but not between different age groups. Serum copper concentration correlated significantly with BMI (p?相似文献   

Using search engine technology for protein function prediction

Prediction of protein function is one of the most challenging problems in the post-genomic era. In this paper, we propose a novel algorithm Improved ProteinRank (IPR) for protein function prediction, which is based on the search engine technology and the preferential attachment criteria. In addition, an improved algorithm IPRW is developed from IPR to be used in the weighted protein?protein interaction (PPI) network. The proposed algorithms IPR and IPRW are applied to the PPI network of S.cerevisiae. The experimental results show that both IPR and IPRW outweigh the previous methods for the prediction of protein functions.     

The ethical landscape of gene drive research

Gene drive technology has immense potential. The ability to bypass the laws of Mendelian inheritance and almost ensure the transmission of specific genetic material to future generations creates boundless possibilities. But alongside these boundless possibilities are major social and ethical issues. This article aims to introduce gene drive technology, some of its potential applications, and some of the social and ethical issues that arise during research into the technology. For example, is investigation into gene drives hubristic? Would applications of gene drives count as technological fixes? Or does research into such a technology sit on a slippery slope or lock us in to its full‐scale use? Are there perverse effects of engaging in research, and, most importantly, who ought to be included in the decision‐making process regarding research and field trials? Understanding the basic ethical landscape of this technology will prove invaluable to the public, scientists, and policy‐makers as research moves forward.     

Weights for data related by a tree

How can one characterize a set of data collected from different biological species, or indeed any set of data related by an evolutionary tree? The structure imposed by the tree implies that the data are not independent, and for most applications this should be taken into account. We describe strategies for weighting the data that circumvent some of the problems of dependency.