1,247 research outputs found

    The relationship between sensory sensitivity and autistic traits in the general population.

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    Individuals with Autism Spectrum Disorders (ASDs) tend to have sensory processing difficulties (Baranek et al. in J Child Psychol Psychiatry 47:591–601, 2006). These difficulties include over- and under-responsiveness to sensory stimuli, and problems modulating sensory input (Ben-Sasson et al. in J Autism Dev Disorders 39:1–11, 2009). As those with ASD exist at the extreme end of a continuum of autistic traits that is also evident in the general population, we investigated the link between ASD and sensory sensitivity in the general population by administering two questionnaires online to 212 adult participants. Results showed a highly significant positive correlation (r = .775, p < .001) between number of autistic traits and the frequency of sensory processing problems. These data suggest a strong link between sensory processing and autistic traits in the general population, which in turn potentially implicates sensory processing problems in social interaction difficulties

    The Shortest Isoform of Dystrophin (Dp40) Interacts with a Group of Presynaptic Proteins to Form a Presumptive Novel Complex in the Mouse Brain

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    Duchenne muscular dystrophy (DMD) causes cognitive impairment in one third of the patients, although the underlying mechanisms remain to be elucidated. Recent studies showed that mutations in the distal part of the dystrophin gene correlate well with the cognitive impairment in DMD patients, which is attributed to Dp71. The study on the expression of the shortest isoform, Dp40, has not been possible due to the lack of an isoform specific antibody. Dp40 has the same promoter as that found in Dp71 and lacks the normal C-terminal end of Dp427. In the present study, we have raised polyclonal antibody against the N-terminal sequence common to short isoforms of dystrophin, including Dp40, and investigated the expression pattern of Dp40 in the mouse brain. Affinity chromatography with this antibody and the consecutive LC-MS/MS analysis on the interacting proteins revealed that Dp40 was abundantly expressed in synaptic vesicles and interacted with a group of presynaptic proteins, including syntaxin1A and SNAP25, which are involved in exocytosis of synaptic vesicles in neurons. We thus suggest that Dp40 may form a novel protein complex and play a crucial role in presynaptic function. Further studies on these aspects of Dp40 function might provide more insight into the molecular mechanisms of cognitive impairment found in patients with DMD

    Posterior lumbar interbody fusion using non resorbable poly-ether-ether-ketone versus resorbable poly-l-lactide-co-d,l-lactide fusion devices. Clinical outcome at a minimum of 2-year follow-up

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    Previous papers on resorbable poly-l-lactide-co-d,l-lactide (PLDLLA) cages in spinal fusion have failed to report adequately on patient-centred clinical outcome measures. Also comparison of PLDLLA cage with a traditionally applicable counterpart has not been previously reported. This is the first randomized prospective study that assesses clinical outcome of PLDLLA cage compared with a poly-ether-ether-ketone (PEEK) implant. Twenty-six patients were randomly assigned to undergo instrumented posterior lumbar interbody fusion (PLIF) whereby either a PEEK cage or a PLDLLA cage was implanted. Clinical outcome based on visual analogue scale scores for leg pain and back pain, as well as Oswestry Disability Index (ODI) and SF-36 questionnaires were documented and analysed. When compared with preoperative values, all clinical parameters have significantly improved in the PEEK group at 2 years after surgery with the exception of SF-36 general health, SF-36 mental health and SF-36 role emotional scores. No clinical parameter showed significant improvement at 2 years after surgery compared with preoperative values in the PLDLLA patient group. Only six patients (50%) in the PLDLLA group showed improvement in the VAS scores for leg and back pain as well as the ODI, as opposed to 10 patients (71%) in the PEEK group. One-third of the patients in the PLDLLA group actually reported worsening of their pain scores and ODI. Three cases of mild to moderate osteolysis were seen in the PLDLLA group. Following up on our preliminary report, these 2-year results confirm the superiority of the PEEK implant to the resorbable PLDLLA implant in aiding spinal fusion and alleviating symptoms following PLIF in patients with degenerative spondylolisthesis associated with either canal stenosis or foramen stenosis or both and emanating from a single lumbar segment

    Compared to conventional, ecological intensive management promotes beneficial proteolytic soil microbial communities for agro-ecosystem functioning under climate change-induced rain regimes

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    Projected climate change and rainfall variability will affect soil microbial communities, biogeochemical cycling and agriculture. Nitrogen (N) is the most limiting nutrient in agroecosystems and its cycling and availability is highly dependent on microbial driven processes. In agroecosystems, hydrolysis of organic nitrogen (N) is an important step in controlling soil N availability. We analyzed the effect of management (ecological intensive vs. conventional intensive) on N-cycling processes and involved microbial communities under climate change-induced rain regimes. Terrestrial model ecosystems originating from agroecosystems across Europe were subjected to four different rain regimes for 263 days. Using structural equation modelling we identified direct impacts of rain regimes on N-cycling processes, whereas N-related microbial communities were more resistant. In addition to rain regimes, management indirectly affected N-cycling processes via modifications of N-related microbial community composition. Ecological intensive management promoted a beneficial N-related microbial community composition involved in N-cycling processes under climate change-induced rain regimes. Exploratory analyses identified phosphorus-associated litter properties as possible drivers for the observed management effects on N-related microbial community composition. This work provides novel insights into mechanisms controlling agro-ecosystem functioning under climate change

    The what and where of adding channel noise to the Hodgkin-Huxley equations

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    One of the most celebrated successes in computational biology is the Hodgkin-Huxley framework for modeling electrically active cells. This framework, expressed through a set of differential equations, synthesizes the impact of ionic currents on a cell's voltage -- and the highly nonlinear impact of that voltage back on the currents themselves -- into the rapid push and pull of the action potential. Latter studies confirmed that these cellular dynamics are orchestrated by individual ion channels, whose conformational changes regulate the conductance of each ionic current. Thus, kinetic equations familiar from physical chemistry are the natural setting for describing conductances; for small-to-moderate numbers of channels, these will predict fluctuations in conductances and stochasticity in the resulting action potentials. At first glance, the kinetic equations provide a far more complex (and higher-dimensional) description than the original Hodgkin-Huxley equations. This has prompted more than a decade of efforts to capture channel fluctuations with noise terms added to the Hodgkin-Huxley equations. Many of these approaches, while intuitively appealing, produce quantitative errors when compared to kinetic equations; others, as only very recently demonstrated, are both accurate and relatively simple. We review what works, what doesn't, and why, seeking to build a bridge to well-established results for the deterministic Hodgkin-Huxley equations. As such, we hope that this review will speed emerging studies of how channel noise modulates electrophysiological dynamics and function. We supply user-friendly Matlab simulation code of these stochastic versions of the Hodgkin-Huxley equations on the ModelDB website (accession number 138950) and http://www.amath.washington.edu/~etsb/tutorials.html.Comment: 14 pages, 3 figures, review articl

    A high-performance matrix-matrix multiplication methodology for CPU and GPU architectures

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    Current compilers cannot generate code that can compete with hand-tuned code in efficiency, even for a simple kernel like matrix–matrix multiplication (MMM). A key step in program optimization is the estimation of optimal values for parameters such as tile sizes and number of levels of tiling. The scheduling parameter values selection is a very difficult and time-consuming task, since parameter values depend on each other; this is why they are found by using searching methods and empirical techniques. To overcome this problem, the scheduling sub-problems must be optimized together, as one problem and not separately. In this paper, an MMM methodology is presented where the optimum scheduling parameters are found by decreasing the search space theoretically, while the major scheduling sub-problems are addressed together as one problem and not separately according to the hardware architecture parameters and input size; for different hardware architecture parameters and/or input sizes, a different implementation is produced. This is achieved by fully exploiting the software characteristics (e.g., data reuse) and hardware architecture parameters (e.g., data caches sizes and associativities), giving high-quality solutions and a smaller search space. This methodology refers to a wide range of CPU and GPU architectures

    The Oogenic Germline Starvation Response in C. elegans

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    Many animals alter their reproductive strategies in response to environmental stress. Here we have investigated how L4 hermaphrodites of Caenorhabditis elegans respond to starvation. To induce starvation, we removed food at 2 h intervals from very early- to very late-stage L4 animals. The starved L4s molted into adulthood, initiated oogenesis, and began producing embryos; however, all three processes were severely delayed, and embryo viability was reduced. Most animals died via ‘bagging,’ because egg-laying was inhibited, and embryos hatched in utero, consuming their parent hermaphrodites from within. Some animals, however, avoided bagging and survived long term. Long-term survival did not rely on embryonic arrest but instead upon the failure of some animals to produce viable progeny during starvation. Regardless of the bagging fate, starved animals showed two major changes in germline morphology: All oogenic germlines were dramatically reduced in size, and these germlines formed only a single oocyte at a time, separated from the remainder of the germline by a tight constriction. Both changes in germline morphology were reversible: Upon re-feeding, the shrunken germlines regenerated, and multiple oocytes formed concurrently. The capacity for germline regeneration upon re-feeding was not limited to the small subset of animals that normally survive starvation: When bagging was prevented ectopically by par-2 RNAi, virtually all germlines still regenerated. In addition, germline shrinkage strongly correlated with oogenesis, suggesting that during starvation, germline shrinkage may provide material for oocyte production. Finally, germline shrinkage and regeneration did not depend upon crowding. Our study confirms previous findings that starvation uncouples germ cell proliferation from germline stem cell maintenance. Our study also suggests that when nutrients are limited, hermaphrodites scavenge material from their germlines to reproduce. We discuss our findings in light of the recently proposed state of dormancy, termed Adult Reproductive Diapause

    Time-dependent failure in load-bearing polymers: a potential hazard in structural applications of polylactides

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    With their excellent biocompatibility and relatively high mechanical strength, polylactides are attractive candidates for application in load-bearing, resorbable implants. Pre-clinical studies provided a proof of principle for polylactide cages as temporary constructs to facilitate spinal fusion, and several cages already made it to the market. However, also failures have been reported: clinical studies reported considerable amounts of subsidence with lumbar spinal fusion cages, and in an in vivo goat study, polylactide spinal cages failed after only three months of implantation, although mechanical testing had predicted sufficient strength for at least eight months. The failures appear to be related to the long-term performance of polylactides under static loading conditions, a phenomenon which is common to all glassy polymers and finds its origin in stress-activated molecular mobility leading to plastic flow. This paper reviews the mechanical properties and deformation kinetics of amorphous polylactides. Compression tests were performed with various strain rates, and static stress experiments were done to determine time-to failure. Pure PLLA appeared to have a higher yield strength than its co-polymers with d-lactide, but the kinetic behaviour of the polymers was the same: an excellent short-term strength at higher loading rates, but lifetime under static stress is rather poor. As spinal implants need to maintain mechanical integrity for a period of at least six months, this has serious implications for the clinical application of amorphous polylactides in load bearing situations. It is recommended that standards for mechanical testing of implants made of polymers be revised in order to consider this typical time-dependent behaviour

    Depression and Sexual Orientation During Young Adulthood: Diversity Among Sexual Minority Subgroups and the Role of Gender Nonconformity.

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    Sexual minority individuals are at an elevated risk for depression compared to their heterosexual counterparts, yet less is known about how depression status varies across sexual minority subgroups (i.e., mostly heterosexuals, bisexuals, and lesbians and gay men). Moreover, studies on the role of young adult gender nonconformity in the relation between sexual orientation and depression are scarce and have yielded mixed findings. The current study examined the disparities between sexual minorities and heterosexuals during young adulthood in concurrent depression near the beginning of young adulthood and prospective depression 6 years later, paying attention to the diversity within sexual minority subgroups and the role of gender nonconformity. Drawn from the National Longitudinal Study of Adolescent Health (N = 9421), we found that after accounting for demographics, sampling weight, and sampling design, self-identified mostly heterosexual and bisexual young adults, but not lesbians and gay men, reported significantly higher concurrent depression compared to heterosexuals; moreover, only mostly heterosexual young adults were more depressed than heterosexuals 6 years later. Furthermore, while young adult gender nonconforming behavior was associated with more concurrent depression regardless of sexual orientation, its negative impact on mental health decreased over time. Surprisingly, previous gender nonconformity predicted decreased prospective depression among lesbians and gay men whereas, among heterosexual individuals, increased gender nonconformity was not associated with prospective depression. Together, the results suggested the importance of investigating diversity and the influence of young adult gender nonconformity in future research on the mental health of sexual minorities.The authors acknowledge support for this research: the University of Arizona Norton School of Family and Consumer Sciences Fitch Nesbitt Endowment and a University of Arizona Graduate Access Fellowship to the second author. This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due Ronald R. Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health website (http://​www.​cpc.​unc.​edu/​addhealth). No direct support was received from grant P01-HD31921 for this analysis. The authors thank Noel Card and Susan Stryker for comments on the previous versions of this article and Richard Lippa and Katerina Sinclair for methodological and statistical consult. The authors also thank the anonymous reviewers and the Editor for their helpful comments.This is the accepted manuscript of a paper published in Archives of Sexual Behavior (Li G, Pollitt AM, Russell ST, Archives of Sexual Behavior 2015, doi:10.1007/s10508-015-0515-3). The final version is available at http://dx.doi.org/10.1007/s10508-015-0515-3
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