Dynamic stereo microscopy for studying particle sedimentation

We demonstrate a new method for measuring the sedimentation of a single colloidal bead by using a combination of optical tweezers and a stereo microscope based on a spatial light modulator. We use optical tweezers to raise a micron-sized silica bead to a fixed height and then release it to observe its 3D motion while it sediments under gravity. This experimental procedure provides two independent measurements of bead diameter and a measure of Faxén’s correction, where the motion changes due to presence of the boundary

X-ray speed reading: enabling fast, low noise readout for next-generation CCDs

Current, state-of-the-art CCDs are close to being able to deliver all key performance figures for future strategic X-ray missions except for the required frame rates. Our Stanford group is seeking to close this technology gap through a multi-pronged approach of microelectronics, signal processing and novel detector devices, developed in collaboration with the Massachusetts Institute of Technology (MIT) and MIT Lincoln Laboratory (MIT-LL). Here we report results from our (integrated) readout electronics development, digital signal processing and novel SiSeRO (Single electron Sensitive Read Out) device characterization.Comment: To appear in SPIE Proceeding of Astronomical Telescopes + Instrumentation, 202

Timing and cost of scaling up surgical services in low-income and middle-income countries from 2012 to 2030 : a modelling study

Background: Given the large burden of surgical conditions and the crosscutting nature of surgery, scale-up of basic surgical services is crucial to health-system strengthening. The Lancet Commission on Global Surgery proposed that, to meet populations' needs, countries should achieve 5000 major operations per 100 000 population per year. We modelled the possible scale-up of surgical services in 88 low-income and middle-income countries with a population greater than 1 million from 2012 to 2030 at various rates and quantified the associated costs. Methods: Major surgery includes any intervention within an operating room involving tissue manipulation and anaesthesia. We used estimates for the number of major operations achieved per country annually and the number of operating rooms per region, and data from Mongolia and Mexico for trends in the number of operations. Unit costs included a cost per operation, proxied by caesarean section cost estimates; hospital construction data were used to estimate cost per operating room construction. We determined the year by which each country would achieve the Commission's target. We modelled three scenarios for the scale-up rate: actual rates (5·1% per year) and two "aspirational" rates, the rates achieved by Mongolia (8·9% annual) and Mexico (22·5% annual). We subsequently estimated the associated costs. Findings: About half of the 88 countries would achieve the target by 2030 at actual rates of improvements, with up to two-thirds if the rate were increased to Mongolian rates. We estimate the total costs of achieving scale-up at US$300-420 billion (95% UI 190-600 billion) over 2012-30, which represents 4-8% of total annual health expenditures among low-income and lower middle-income countries and 1% among upper middle-income countries. Interpretation: Scale-up of surgical services will not reach the target of 5000 operations per 100 000 by 2030 in about half of low-income and middle-income countries without increased funding, which countries and the international community must seek to achieve expansion of quality surgical services

Strategic responses to global challenges: The case of European banking, 1973–2000

In applying a strategy, structure, ownership and performance (SSOP) framework to three major clearing banks (ABN AMRO, UBS, Barclays), this article debates whether the conclusions generated by Whittington and Mayer about European manufacturing industry can be applied to the financial services sector. While European integration plays a key role in determining strategy, it is clear that global factors were far more important in determining management actions, leading to significant differences in structural adaptation. The article also debates whether this has led to improved performance, given the problems experienced with both geographical dispersion and diversification, bringing into question the quality of decision-making over the long term

Global access to surgical care: a modelling study

Background More than 2 billion people are unable to receive surgical care based on operating theatre density alone. The vision of the Lancet Commission on Global Surgery is universal access to safe, aff ordable surgical and anaesthesia care when needed. We aimed to estimate the number of individuals worldwide without access to surgical services as defi ned by the Commission’s vision. Methods We modelled access to surgical services in 196 countries with respect to four dimensions: timeliness, surgical capacity, safety, and aff ordability. We built a chance tree for each country to model the probability of surgical access with respect to each dimension, and from this we constructed a statistical model to estimate the proportion of the population in each country that does not have access to surgical services. We accounted for uncertainty with oneway sensitivity analyses, multiple imputation for missing data, and probabilistic sensitivity analysis. Findings At least 4·8 billion people (95% posterior credible interval 4·6–5·0 [67%, 64–70]) of the world’s population do not have access to surgery. The proportion of the population without access varied widely when stratifi ed by epidemiological region: greater than 95% of the population in south Asia and central, eastern, and western sub- Saharan Africa do not have access to care, whereas less than 5% of the population in Australasia, high-income North America, and western Europe lack access. Interpretation Most of the world’s population does not have access to surgical care, and access is inequitably distributed. The near absence of access in many low-income and middle-income countries represents a crisis, and as the global health community continues to support the advancement of universal health coverage, increasing access to surgical services will play a central role in ensuring health care for all

Single electron Sensitive Readout (SiSeRO) X-ray detectors: Technological progress and characterization

Single electron Sensitive Read Out (SiSeRO) is a novel on-chip charge detector output stage for charge-coupled device (CCD) image sensors. Developed at MIT Lincoln Laboratory, this technology uses a p-MOSFET transistor with a depleted internal gate beneath the transistor channel. The transistor source-drain current is modulated by the transfer of charge into the internal gate. At Stanford, we have developed a readout module based on the drain current of the on-chip transistor to characterize the device. Characterization was performed for a number of prototype sensors with different device architectures, e.g. location of the internal gate, MOSFET polysilicon gate structure, and location of the trough in the internal gate with respect to the source and drain of the MOSFET (the trough is introduced to confine the charge in the internal gate). Using a buried-channel SiSeRO, we have achieved a charge/current conversion gain of >700 pA per electron, an equivalent noise charge (ENC) of around 6 electrons root mean square (RMS), and a full width half maximum (FWHM) of approximately 140 eV at 5.9 keV at a readout speed of 625 Kpixel/s. In this paper, we discuss the SiSeRO working principle, the readout module developed at Stanford, and the characterization test results of the SiSeRO prototypes. We also discuss the potential to implement Repetitive Non-Destructive Readout (RNDR) with these devices and the preliminary results which can in principle yield sub-electron ENC performance. Additional measurements and detailed device simulations will be essential to mature the SiSeRO technology. However, this new device class presents an exciting technology for next generation astronomical X-ray telescopes requiring fast, low-noise, radiation hard megapixel imagers with moderate spectroscopic resolution.Comment: To appear in SPIE Proceedings of Astronomical Telescopes + Instrumentation, 202

Recruitment in the sea: bacterial genes required for inducing larval settlement in a polychaete worm

Metamorphically competent larvae of the marine tubeworm Hydroides elegans can be induced to metamorphose by biofilms of the bacterium Pseudoalteromonas luteoviolacea strain HI1. Mutational analysis was used to identify four genes that are necessary for metamorphic induction and encode functions that may be related to cell adhesion and bacterial secretion systems. No major differences in biofilm characteristics, such as biofilm cell density, thickness, biomass and EPS biomass, were seen between biofilms composed of P. luteoviolacea (HI1) and mutants lacking one of the four genes. The analysis indicates that factors other than those relating to physical characteristics of biofilms are critical to the inductive capacity of P. luteoviolacea (HI1), and that essential inductive molecular components are missing in the non-inductive deletion-mutant strains

Size and distribution of the global volume of surgery in 2012

Abstract Objective: To estimate global surgical volume in 2012 and compare it with estimates from 2004. Methods: For the 194 Member States of the World Health Organization, we searched PubMed for studies and contacted key informants for reports on surgical volumes between 2005 and 2012. We obtained data on population and total health expenditure per capita for 2012 and categorized Member States as very-low, low, middle and high expenditure. Data on caesarean delivery were obtained from validated statistical reports. For Member States without recorded surgical data, we estimated volumes by multiple imputation using data on total health expenditure. We estimated caesarean deliveries as a proportion of all surgery. Findings: We identified 66 Member States reporting surgical data. We estimated that 312.9 million operations (95% confidence interval, CI: 266.2–359.5) took place in 2012, an increase from the 2004 estimate of 226.4 million operations. Only 6.3% (95% CI: 1.7–22.9) and 23.1% (95% CI: 14.8–36.7) of operations took place in very-low- and low-expenditure Member States representing 36.8% (2573 million people) and 34.2% (2393 million people) of the global population of 7001 million people, respectively. Caesarean deliveries comprised 29.6% (5.8/19.6 million operations; 95% CI: 9.7–91.7) of the total surgical volume in very-low-expenditure Member States, but only 2.7% (5.1/187.0 million operations; 95% CI: 2.2–3.4) in high-expenditure Member States. Conclusion: Surgical volume is large and growing, with caesarean delivery comprising nearly a third of operations in most resource-poor settings. Nonetheless, there remains disparity in the provision of surgical services globally

Hormonal signaling in cnidarians : do we understand the pathways well enough to know whether they are being disrupted?

Author Posting. © The Author, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ecotoxicology 16 (2007): 5-13, doi:10.1007/s10646-006-0121-1.Cnidarians occupy a key evolutionary position as basal metazoans and are ecologically important as predators, prey and structure-builders. Bioregulatory molecules (e.g., amines, peptides and steroids) have been identified in cnidarians, but cnidarian signaling pathways remain poorly characterized. Cnidarians, especially hydras, are regularly used in toxicity testing, but few studies have used cnidarians in explicit testing for signal disruption. Sublethal endpoints developed in cnidarians include budding, regeneration, gametogenesis, mucus production and larval metamorphosis. Cnidarian genomic databases, microarrays and other molecular tools are increasingly facilitating mechanistic investigation of signaling pathways and signal disruption. Elucidation of cnidarian signaling processes in a comparative context can provide insight into the evolution and diversification of metazoan bioregulation. Characterizing signaling and signal disruption in cnidarians may also provide unique opportunities for evaluating risk to valuable marine resources, such as coral reefs

Establishment of a Statewide Network for Carbapenem-Resistant Enterobacteriaceae Prevention in a Low-Incidence Region

OBJECTIVE: To establish a statewide network to detect, control, and prevent the spread of carbapenem-resistant Enterobacteriaceae (CRE) in a region with a low incidence of CRE infection. DESIGN: Implementation of the Drug Resistant Organism Prevention and Coordinated Regional Epidemiology (DROP-CRE) Network. SETTING AND PARTICIPANTS: Oregon infection prevention and microbiology laboratory personnel, including 48 microbiology laboratories, 62 acute care facilities, and 140 long-term care facilities. METHODS: The DROP-CRE working group, comprising representatives from academic institutions and public health, convened an interdisciplinary advisory committee to assist with planning and implementation of CRE epidemiology and control efforts. The working group established a statewide CRE definition and surveillance plan; increased the state laboratory capacity to perform the modified Hodge test and polymerase chain reaction for carbapenemases in real time; and administered surveys that assessed the needs and capabilities of Oregon infection prevention and laboratory personnel. Results of these inquiries informed CRE education and the response plan. RESULTS: Of 60 CRE reported from November 2010 through April 2013, only 3 were identified as carbapenemase producers; the cases were not linked, and no secondary transmission was found. Microbiology laboratories, acute care facilities, and long-term care facilities reported lacking carbapenemase testing capability, reliable interfacility communication, and CRE awareness, respectively. Survey findings informed the creation of the Oregon CRE Toolkit, a state-specific CRE guide booklet. CONCLUSIONS: A regional epidemiology surveillance and response network has been implemented in Oregon in advance of widespread CRE transmission. Prospective surveillance will determine whether this collaborative approach will be successful at forestalling the emergence of this important healthcare-associated pathogen.This is the publisher’s final pdf. The published article is copyrighted by the University of Chicago Press on behalf of the Society for Healthcare Epidemiology of America and can be found at: http://www.press.uchicago.edu/ucp/journals/journal/iche.html