Effects of submersion on VO2: comparing maximum aerobic exertion on land and underwater.

Introduction: Submersion results in blood redistribution into the pulmonary circulation, causing changes in pulmonary compliance and increased cardiac preload. Few studies have compared incremental exercise to exhaustion (VO2 max testing) in a dry environment with exercise underwater. We hypothesized that the physiological effects of submersion would result in lower heart rate (HR), minute ventilation (VE), and peak oxygen uptake (VO2 peak) compared with dry conditions. Methods: Fourteen male and four female volunteers completed two VO2 peak testing sessions with approximately two hours between trials: first in the dry laboratory on a cycle ergometer and second while fully submersed in a prone position with zero static lung load. HR was monitored via ECG, and inspiratory and expiratory gas compositions were recorded using a metabolic cart. The tests were terminated once the subject reached exhaustion. Results: Absolute VO2 peak was lower in the submersed VO2 max trial (37.1 ± 7.0 mL•kg-1•min-1) compared with dry exercise (45.8 ± 8.9 mL•kg-1•min-1) p < 0.001. HR and VE were also lower in the submersed trial. Conclusions: VO2 peak while submersed is reduced relative to dry VO2 peak, which may be partly due to a decrease in heart rate and a reduction in VE.

A fluidic demultiplexer for controlling large arrays of soft actuators.

The field of soft robotics endeavors to create robots that are mostly, if not entirely, soft. While there have been significant advances in both soft actuators and soft sensors, there has been relatively little work done in the development of soft control systems. This work proposes a soft microfluidic demultiplexer as a potential control system for soft robotics. Demultiplexers enable the control of many outputs with just a few inputs, increasing a soft robot's complexity while minimizing its reliance on external valves and other off-board components. The demultiplexer in this work improves upon earlier microfluidic demultiplexers with its nearly two-fold reduction of inputs, a design feature that simplifies control and increases efficiency. Additionally, the demultiplexer in this work is designed to accommodate the high pressures and flow rates that soft robotics demands. The demultiplexer is characterized from the level of individual valves to full system parameters, and its functionality is demonstrated by controlling an array of individually addressable soft actuators.

Idling in Mao's Shadow: Heroin Addiction and the Contested Therapeutic Value of Socialist Traditions of Laboring.

The Chinese government has come under attack by international critics for forcing drug users to labor in the name of treatment. While joining these activists in criticizing conditions in compulsory labor centers, former detainees who congregated at a drop-in center in southern Yunnan also defended the therapeutic potential of socialist legacies of laboring. Shuttling between laboring in state compulsory centers and idling in a market economy, long-term heroin users saw their difficulties in recovering from addiction as inextricably linked to their inability to find suitable work opportunities. Certain drop-in center attendees maintained that earlier Communist laboring projects had helped wayward citizens, including drug addicts, "merge into" society as productive workers. This group evoked the stable long-term jobs and benefits once provided by local state-owned enterprises and the radical revolutionary power of "remolding through labor" they imagined to have existed in the first years of the People's Republic as powerful alternatives to their recent crisis of idling. The nuanced ways that drop-in center regulars revisited the potential healing power of earlier traditions of socialist laboring as remedies to their contemporary struggles complicates long-standing debates about coercion in treatment and the responsibility of the postsocialist state towards marginalized workers.

Endogenously imprinted genes in Drosophila melanogaster.

Genomic imprinting is an epigenetic state that results from differential processing of chromosomes during gametogenesis and which can cause differential expression of genes depending on the sex of the parent transmitting that gene. In Drosophila, many examples of imprinted marker genes have been documented and imprinting of these genes involves highly conserved epigenetic regulators. However, no endogenously imprinted genes have yet been identified. Here we present a phenotypic and transcriptional analysis of parthenogenetic (gynogenetic) and genotypically identical but sexually produced adult female Drosophila. We find that while parthenogenetic females have a superficially normal phenotype and are viable and fertile, their lifespan is extended relative to their sexually-produced counterparts. Microarray/transcriptional analysis of parthenogenetic versus sexually-produced females reveals 76 genes with consistently altered patterns of expression, 36 upregulated and 40 downregulated, some with known effects on aging. Analysis of individuals with uniparental inheritance of only portions of their genome suggest that many of these genes may be indirectly imprinted, responding to either other imprinted genes or redistribution of chromatin components that are differentially allocated to sex and autosomal heterochromatin in a sex-dependent manner during gametogenesis. As gene expression dependent on the parental origin of the genome meets the definition of genomic imprinting, our study provides evidence that endogenous genes are imprinted in Drosophila.

Comparing the Nidek MP-1 and Humphrey field analyzer in normal subjects.

PURPOSE: To compare visual fields on the Nidek MP-1 to those obtained on the Humphrey field analyzer (HFA) in healthy volunteers and assess the effects of differences in stimulus parameters and testing strategies that may influence the interpretation of results in patients. A secondary aim was to establish MP-1 normative data to calculate the total deviation analyses and global indices analogous to those used by the HFA. METHODS: Fifty healthy volunteers (age 43.5 ± 13.9 years, range, 18 to 68 years) underwent repeat MP-1 and HFA visual field testing, using the 10-2 pattern. MP-1 data were converted to HFA equivalent dB units. Between instrument comparisons of HFA and MP-1 sensitivities, regression of sensitivity with age and examination duration were assessed. Test-retest variability was examined between visits. RESULTS: MP-1 (mean = 32.82 dB, SD = 1.92 dB) and HFA sensitivities (mean = 32.84 dB, SD = 1.83 dB) were not significantly different (p = 0.759). SD values for the HFA (range, 1.11 to 3.30 dB) were similar to the MP-1 (range, 0.14 to 2.75 dB). However, asymmetry comparisons between instruments showed significantly decreased superior rather than inferior retinal values for the MP-1. There was a small but significant difference (p = 0.004) in mean test duration between the MP-1 (mean = 6:11 min, SD = 1:49 min) and the HFA (mean = 5:14 min, SD = 0:42 min). There was also a difference in the decline of mean sensitivity with age, a decline of 0.1 and 0.4 dB per decade was noted in MP-1 and HFA sensitivity, respectively. Test-retest variability was similar between instruments. A small but non-significant increase in mean sensitivity at the second visit for both the MP-1 (p = 0.060) and HFA (p = 0.570) was found. CONCLUSIONS: Both instruments showed similar variability and test-retest variability when results were compared using equivalent units. However, there are important differences in sensitivity values, stimulus parameters, and testing strategies that have to be taken into account when comparisons are made.

The Drosophila homolog of the mammalian imprint regulator, CTCF, maintains the maternal genomic imprint in Drosophila melanogaster.

BACKGROUND: CTCF is a versatile zinc finger DNA-binding protein that functions as a highly conserved epigenetic transcriptional regulator. CTCF is known to act as a chromosomal insulator, bind promoter regions, and facilitate long-range chromatin interactions. In mammals, CTCF is active in the regulatory regions of some genes that exhibit genomic imprinting, acting as insulator on only one parental allele to facilitate parent-specific expression. In Drosophila, CTCF acts as a chromatin insulator and is thought to be actively involved in the global organization of the genome. RESULTS: To determine whether CTCF regulates imprinting in Drosophila, we generated CTCF mutant alleles and assayed gene expression from the imprinted Dp(1;f)LJ9 mini-X chromosome in the presence of reduced CTCF expression. We observed disruption of the maternal imprint when CTCF levels were reduced, but no effect was observed on the paternal imprint. The effect was restricted to maintenance of the imprint and was specific for the Dp(1;f)LJ9 mini-X chromosome. CONCLUSIONS: CTCF in Drosophila functions in maintaining parent-specific expression from an imprinted domain as it does in mammals. We propose that Drosophila CTCF maintains an insulator boundary on the maternal X chromosome, shielding genes from the imprint-induced silencing that occurs on the paternally inherited X chromosome. See commentary: http://www.biomedcentral.com/1741-7007/8/104.

Increasing the Dimensionality of Soft Microstructures through Injection-Induced Self-Folding.

Devices fabricated using soft materials have been a major research focus of late, capturing the attention of scientists and laypersons alike in a wide range of fields, from microfluidics to robotics. The functionality of such devices relies on their structural and material properties; thus, the fabrication method is of utmost importance. Here, multilayer soft lithography, precision laser micromachining, and folding to establish a new paradigm are combined for creating 3D soft microstructures and devices. Phase-changing materials are exploited to transform actuators into structural elements, allowing 2D laminates to evolve into a third spatial dimension. To illustrate the capabilities of this new fabrication paradigm, the first "microfluidic origami for reconfigurable pneumatic/hydraulic" device is designed and manufactured: a 12-layer soft robotic peacock spider with embedded microfluidic circuitry and actuatable features.

SOFT ROBOTICS. A 3D-printed, functionally graded soft robot powered by combustion.

Roboticists have begun to design biologically inspired robots with soft or partially soft bodies, which have the potential to be more robust and adaptable, and safer for human interaction, than traditional rigid robots. However, key challenges in the design and manufacture of soft robots include the complex fabrication processes and the interfacing of soft and rigid components. We used multimaterial three-dimensional (3D) printing to manufacture a combustion-powered robot whose body transitions from a rigid core to a soft exterior. This stiffness gradient, spanning three orders of magnitude in modulus, enables reliable interfacing between rigid driving components (controller, battery, etc.) and the primarily soft body, and also enhances performance. Powered by the combustion of butane and oxygen, this robot is able to perform untethered jumping.

What's in the 'treatment gap'? Ethnographic perspectives on addiction and global mental health from China, Russia, and the United States.

Recent years have seen the emergence of a 'global mental health' agenda, focused on providing evidence-based interventions for mental illnesses in low- and middle-income countries. Anthropologists and cultural psychiatrists have engaged in vigorous debates about the appropriateness of this agenda. In this article, we reflect on these debates, drawing on ethnographic fieldwork on the management of substance use disorders in China, Russia, and the United States. We argue that the logic of 'treatment gaps,' which guides much research and intervention under the rubric of global mental health, partially obscures the complex assemblages of institutions, therapeutics, knowledges, and actors framing and managing addiction (as well as other mental health issues) in any particular setting.

A harm reduction paradox: comparing China's policies on needle and syringe exchange and methadone maintenance.

BACKGROUND: China has launched methadone maintenance treatment (MMT) and needle and syringe exchange programmes (NSEP) as part of the country's HIV prevention strategy amongst injection drug users. MMT is expanding, with backing from multiple government ministries, however, NSEP have received less political support and funding. METHODS: Semi-structured, serial interviews were conducted with key informants, knowledgeable about China's harm reduction policies. Concurrent content analysis allowed for revision of the interview guide throughout the data collection process. This was combined with a systematic analysis of official government policy documents on NSEP and MMT, including white papers, legal documents, and policy statements. FINDINGS: Early consensus between public security and public health sectors regarding methadone's dual use in HIV prevention as well as method of drug control created broad institutional support for MMT programmes amongst policy makers. In contrast, NSEP were seen as satisfying only the HIV prevention goals of the public health sector, and were perceived as condoning illicit drug use. Furthermore, NSEP's roots in China, as an experimental collaboration with international groups, created suspicion regarding its role in China's drug control policy. NSEP and MMT's distinct paths to policy development are reflected in the complex and occasionally contradictory nature of China's harm reduction strategy. CONCLUSIONS: These discrepancies highlight the need for a more politically sustainable and comprehensive integration of harm reduction projects. Recommendations include improved evaluation methods for NESP, NSEP-MMT cross-referral system, and stronger NSEP advocacy within the non-profit and public health sectors.

Daphnia as an emerging epigenetic model organism.

Daphnia offer a variety of benefits for the study of epigenetics. Daphnia's parthenogenetic life cycle allows the study of epigenetic effects in the absence of confounding genetic differences. Sex determination and sexual reproduction are epigenetically determined as are several other well-studied alternate phenotypes that arise in response to environmental stressors. Additionally, there is a large body of ecological literature available, recently complemented by the genome sequence of one species and transgenic technology. DNA methylation has been shown to be altered in response to toxicants and heavy metals, although investigation of other epigenetic mechanisms is only beginning. More thorough studies on DNA methylation as well as investigation of histone modifications and RNAi in sex determination and predator-induced defenses using this ecologically and evolutionarily important organism will contribute to our understanding of epigenetics.

Attitudes and knowledge about naloxone and overdose prevention among detained drug users in Ningbo, China.

BACKGROUND: To date there has been limited research on both the prevalence of overdose and drug user knowledge about overdose prevention and response methods in China. In addition, there has been no effort to integrate naloxone information and distribution into pre-release services for drug users detained in isolated compulsory detoxification facilities in China. METHODS: The authors conducted a survey of 279 heroin users in isolated compulsory detoxification centers in Ningbo, China in an attempt to evaluate the possibility of conducting prelease peer naloxone programs in Ningbo isolated compulsory detoxification centers. Respondents' demographic background, history of heroin overdoses, and attitudes/knowledge about overdose prevention and response were collected. RESULTS: While drug users in Ningbo's compulsory detoxification centers have limited understandings of how to effectively respond to overdoses, they expressed concern about the possibility of overdose, interest in participating in overdose prevention and response programs, and a willingness to help their peers. In general, there was no significant difference in history and attitudes/knowledge of overdose between male and female participants. CONCLUSION: Based on the findings of this research, our survey provides preliminary evidence that detained drug users have considerable interest in overdose prevention and response information and willingness to help peers. However, drug users in Ningbo isolated compulsory detoxification centers currently have limited understandings of effective ways of helping to prevent overdose deaths.

A qualitative evaluation of a peer-implemented overdose response pilot project in Gejiu, China.

BACKGROUND: A harm reduction NGO in southern Yunnan operating an emergency overdose response hotline service successfully reversed 76 overdoses through the administration of naloxone in one of the first interventions of its kind in China. METHOD: To explore local understandings of risk factors related to overdose, assess ongoing barriers to overdose response, and solicit client input on how to further reduce opiate overdose mortality in Gejiu, the authors conducted qualitative interviews with 30 clients, including 15 individuals who received naloxone injections to reverse an overdose and 15 individuals who called the hotline in response to the overdose of a peer. RESULTS: Participants pointed to a number of local structural shifts in heroin use including the ageing of the opiate using population and drug mixing practises that contribute to the city's overdose toll. Concerns over medical professionals' willingness to treat drug users, protection of confidentiality, and financial costs associated with treatment frequently cause drug users to avoid contact with the city's emergency service providers. Participants suggest directly distributing naloxone to clients as one strategy to further reduce overdose mortality. CONCLUSION: The authors explore possible strategies, including targeted trainings and new partnerships with local hospitals, to further reduce opiate overdose mortality in this resource-poor setting.