99 research outputs found

    Battery-Operated Atomic Force Microscope

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    The design of a battery-operated atomic force microscope (AFM) using a piezoresistive cantilever is described. The AFM is designed so that all power to drive the scanning tube and detection electronics comes from a self-contained battery. The prototype AFM uses a 6 V, Ni–Cd, camcorder battery, however, any battery that supplies between 6 and 12 V may be used. Scanner control and data acquisition are implemented using commercially available software running on an external computer. The prototype AFM achieves a scan area of 53 by 53 μm, consumes 1.8 W of power, and can scan continuously for about 7 h on a single battery charge

    Gestational age and birth weight and the risk of childhood type 1 diabetes : a population-based cohort and sibling design study

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    Objectives: We investigated the effects of gestational age, birthweight, small for gestational age (SGA) and large for gestational age (LGA) on childhood type 1 diabetes. Methods: We conducted a population-based cohort study of all singleton live births in Sweden between 1973-2009 and a sibling-control study. Perinatal data were extracted from the Swedish Medical Birth Register. Children with type 1 diabetes diagnosis were identified from the Swedish National Patient Register. Log-linear Poisson regression and conditional logistic regression were used for data analysis. Results: The study cohort consisted of 3,624,675 singleton live births (42,411,054 person-years). There were 13,944 type 1 diabetes cases during the study period. The sibling-control study consisted of 11,403 children with type 1 diabetes and 17,920 siblings. Gestational age between 33-36 weeks (RR=1.18; [95%CIs: 1.09, 1.28) and 37-38 weeks (RR=1.12; [95%CIs: 1.07, 1.17]) was associated with type 1 diabetes in the cohort study and remained significant in the sibling-control study. SGA (RR=0.83; [95%CIs: 0.75, 0.93]) and LGA (RR=1.14; [95%CIs: 1.04, 1.24]) were associated with type 1 diabetes in the cohort study. The SGA association remained unchanged in the sibling study while the LGA association disappeared. Very low birthweight was associated with a reduced risk of type 1 diabetes. Conclusions: The findings suggest a small association between gestational age and type 1 diabetes that is not likely due to familial confounding factors. Gestational age and type 1 diabetes may be related to insulin resistance due to early life growth restriction or altered gut microbiota in preterm babies.Science Foundation Ireland, Grant Number 12/RC/2272Stockholm County Council (ALF)Manuscrip

    A comparative assessment of the information technology services sector in India and China

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    The purpose of this paper is to assess the nature of competition in the information technology (IT) services sector between India and China. Using primary and secondary data sources, we compare and contrast the strengths and weaknesses of the IT services sector in the two countries along the main dimensions of Porter&rsquo;s competitive advantage model. The principal findings indicate that the IT services sectors in the two countries are distinctively different, have developed along different paths and are highly complementary to each other. China has a well established hardware sector and its IT services sector focuses mostly on servicing its domestic market. India&rsquo;s IT services sector is predominantly export orientated with focus on the US and Western European markets. Contrary to popular beliefs, given the complementary characteristics of the IT services sectors in India and China, it is unlikely for the two countries to compete against each other in the near future and greater strategic co-operation between IT service providers in the two countries is a more likely outcome.<br /

    Assessing the congruence of thermal niche estimations derived from distribution and physiological data. A test using diving beetles.

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    A basic aim of ecology is to understand the determinants of organismal distribution, the niche concept and species distribution models providing key frameworks to approach the problem. As temperature is one of the most important factors affecting species distribution, the estimation of thermal limits is crucially important for inferring range constraints. It is expectable that thermal physiology data derived from laboratory experiments and species' occurrences may express different aspects of the species' niche. However, there is no study systematically testing this prediction in a given taxonomic group while controlling by potential phylogenetic inertia. We estimate the thermal niches of twelve Palaearctic diving beetles species using physiological data derived from experimental analyses in order to examine the extent to which these coincided with those estimated from distribution models based on observed occurrences. We found that thermal niche estimates derived from both approaches lack general congruence, and these results were similar before and after controlling by phylogeny. The congruence between potential distributions obtained from the two different procedures was also explored, and we found again that the percentage of agreement were not very high (~60%). We confirm that both thermal niche estimates derived from geographical and physiological data are likely to misrepresent the true range of climatic variation that these diving beetles are able to tolerate, and so these procedures could be considered as incomplete but complementary estimations of an inaccessible reality

    Australia's Dengue Risk Driven by Human Adaptation to Climate Change

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    Current and projected rainfall reduction in southeast Australia has seen the installation of large numbers of government-subsidised and ad hoc domestic water storage containers that could create the possibility of the mosquito Ae. aegypti expanding out of Queensland into southern Australian's urban regions. By assessing the past and current distribution of Ae. aegypti in Australia, we construct distributional models for this dengue vector for our current climate and projected climates for 2030 and 2050. The resulting mosquito distribution maps are compared to published theoretical temperature limits for Ae. aegypti and some differences are identified. Nonetheless, synthesising our mosquito distribution maps with dengue transmission climate limits derived from historical dengue epidemics in Australia suggests that the current proliferation of domestic water storage tanks could easily result in another range expansion of Ae. aegypti along with the associated dengue risk were the virus to be introduced

    Genomic aberrations in borderline ovarian tumors

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    <p>Abstract</p> <p>Background</p> <p>According to the scientific literature, less than 30 borderline ovarian tumors have been karyotyped and less than 100 analyzed for genomic imbalances by CGH.</p> <p>Methods</p> <p>We report a series of borderline ovarian tumors (n = 23) analyzed by G-banding and karyotyping as well as high resolution CGH; in addition, the tumors were analyzed for microsatellite stability status and by FISH for possible 6q deletion.</p> <p>Results</p> <p>All informative tumors were microsatellite stable and none had a deletion in 6q27. All cases with an abnormal karyotype had simple chromosomal aberrations with +7 and +12 as the most common. In three tumors with single structural rearrangements, a common breakpoint in 3q13 was detected. The major copy number changes detected in the borderline tumors were gains from chromosome arms 2q, 6q, 8q, 9p, and 13q and losses from 1p, 12q, 14q, 15q, 16p, 17p, 17q, 19p, 19q, and 22q. The series included five pairs of bilateral tumors and, in two of these pairs, informative data were obtained as to their clonal relationship. In both pairs, similarities were found between the tumors from the right and left side, strongly indicating that bilaterality had occurred via a metastatic process. The bilateral tumors as a group showed more aberrations than did the unilateral ones, consistent with the view that bilaterality is a sign of more advanced disease.</p> <p>Conclusion</p> <p>Because some of the imbalances found in borderline ovarian tumors seem to be similar to imbalances already known from the more extensively studied overt ovarian carcinomas, we speculate that the subset of borderline tumors with detectable imbalances or karyotypic aberrations may contain a smaller subset of tumors with a tendency to develop a more malignant phenotype. The group of borderline tumors with no imbalances would, in this line of thinking, have less or no propensity for clonal evolution and development to full-blown carcinomas.</p
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