258 research outputs found
The cuttlefish Sepia officinalis (Sepiidae, Cephalopoda) constructs cuttlebone from a liquid-crystal precursor
Cuttlebone, the sophisticated buoyancy device of cuttlefish, is made of extensive superposed chambers that have a complex internal arrangement of calcified pillars and organic membranes. It has not been clear how this structure is assembled. We find that the membranes result from a myriad of minor membranes initially filling the whole chamber, made of nanofibres evenly oriented within each membrane and slightly rotated with respect to those of adjacent membranes, producing a helical arrangement. We propose that the organism secretes a chitin-protein complex, which self-organizes layer-by-layer as a cholesteric liquid crystal, whereas the pillars are made by viscous fingering. The liquid crystallization mechanism permits us to homologize the elements of the cuttlebone with those of other coleoids and with the nacreous septa and the shells of nautiloids. These results challenge our view of this ultra-light natural material possessing desirable mechanical, structural and biological properties, suggesting that two self-organizing physical principles suffice to understand its formation.Spanish Ministerio de Ciencia e Innovacion [CGL2010-20748-CO2-01, CGL2013-48247-P, FIS2013-48444-C2-2-P]; Andalusian Consejeria de Innovacion Ciencia y Tecnologia [RNM6433]; (Sepiatech, PROMAR program) of the Portuguese Ministerio da Agricultura e do Mar, Portugal [31.03.05.FEP.002]; Junta de Andalucia [RNM363]; FP7 COST Action of the European Community. [TD0903]info:eu-repo/semantics/publishedVersio
A software pipeline for processing and identification of fungal ITS sequences
<p>Abstract</p> <p>Background</p> <p>Fungi from environmental samples are typically identified to species level through DNA sequencing of the nuclear ribosomal internal transcribed spacer (<it>ITS</it>) region for use in BLAST-based similarity searches in the International Nucleotide Sequence Databases. These searches are time-consuming and regularly require a significant amount of manual intervention and complementary analyses. We here present software – in the form of an identification pipeline for large sets of fungal <it>ITS </it>sequences – developed to automate the BLAST process and several additional analysis steps. The performance of the pipeline was evaluated on a dataset of 350 <it>ITS </it>sequences from fungi growing as epiphytes on building material.</p> <p>Results</p> <p>The pipeline was written in Perl and uses a local installation of NCBI-BLAST for the similarity searches of the query sequences. The variable subregion <it>ITS2 </it>of the <it>ITS </it>region is extracted from the sequences and used for additional searches of higher sensitivity. Multiple alignments of each query sequence and its closest matches are computed, and query sequences sharing at least 50% of their best matches are clustered to facilitate the evaluation of hypothetically conspecific groups. The pipeline proved to speed up the processing, as well as enhance the resolution, of the evaluation dataset considerably, and the fungi were found to belong chiefly to the <it>Ascomycota</it>, with <it>Penicillium </it>and <it>Aspergillus </it>as the two most common genera. The <it>ITS2 </it>was found to indicate a different taxonomic affiliation than did the complete <it>ITS </it>region for 10% of the query sequences, though this figure is likely to vary with the taxonomic scope of the query sequences.</p> <p>Conclusion</p> <p>The present software readily assigns large sets of fungal query sequences to their respective best matches in the international sequence databases and places them in a larger biological context. The output is highly structured to be easy to process, although it still needs to be inspected and possibly corrected for the impact of the incomplete and sometimes erroneously annotated fungal entries in these databases. The open source pipeline is available for UNIX-type platforms, and updated releases of the target database are made available biweekly. The pipeline is easily modified to operate on other molecular regions and organism groups.</p
Evaluation of host-derived volatiles for trapping Culicoides biting midges (Diptera: Ceratopogonidae)
Culicoides biting midges (Diptera: Ceratopognidae) cause pain and distress through blood feeding, and transmit viruses that threaten both animal and human health worldwide. There are few effective tools for monitoring and control of biting midges, with semiochemical-based strategies offering the advantage of targeting host-seeking populations. In previous studies, we identified the host preference of multiple Culicoides species, including Culicoides impunctatus, as well as cattle-derived compounds that modulate the behavioral responses of C. nubeculosus under laboratory conditions. Here, we test the efficacy of these compounds, when released at different rates, in attracting C. impunctatus under field conditions in Southern Sweden. Traps releasing 1-octen-3-ol, decanal, phenol, 4-methylphenol or 3-propylphenol, when combined with carbon dioxide (CO2), captured significantly higher numbers of C. impunctatus compared to control traps baited with CO2 alone, with low release rates (0.1 mg h−1, 1 mg h−1) being generally more attractive. In contrast, traps releasing octanal or (E)-2-nonenal at 1 mg h−1 and 10 mg h−1 collected significantly lower numbers of C. impunctatus than control traps baited with CO2 only. Nonanal and 2-ethylhexanol did not affect the attraction of C. impunctatus when compared to CO2 alone at any of the release rates tested. The potential use of these semiochemicals as attractants and repellents for biting midge control is discussed
Scintigraphic evaluation of oesophageal transit during radiotherapy to the mediastinum
Background: To quantitatively evaluate radiation-induced impaired oesophageal transit with oesophageal transit scintigraphy and to assess the relationships between acute oesophagitis symptoms and dysmotility.\ud
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Methods: Between January 1996 and November 1998, 11 patients affected by non-small-cell carcinoma of the lung not directly involving the oesophagus, requiring adjuvant external beam radiotherapy (RT) to the mediastinum were enrolled. Oesophageal transit scans with liquid and semisolid bolus were performed at three pre-defined times: before (T0) and during radiation at 10 Gy (T1) and 30 Gy (T2). Two parameters were obtained for evaluation: 1) mean transit time (MTT); and 2) ratio between peak activity and residual activity at 40 seconds (ER-40s). Acute radiation toxicity was scored according to the joint EORTC-RTOG criteria. Mean values with standard deviation were calculated for all parameters. Analysis of variance (ANOVA) tests and paired t-Tests for all values were performed.\ud
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Results: An increase in the ER-40s from T0 to T1 or T2 was seen in 9 of 11 patients (82%). The mean ER-40s value for all patients increased from 0.8306 (T0) to 0.8612 (T1) and 0.8658 (T2). These differences were statistically significant (p < 0.05) in two paired t-Tests at T0 versus T2 time: overall mean ER-40s and upright ER-40s (p = 0.041 and p = 0.032, respectively). Seven patients (63%) showed a slight increase in the mean MTT value during irradiation but no statistically significant differences in MTT parameters were found between T0, T1 and T2 (p > 0.05).\ud
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Conclusion: Using oesophageal scintigraphy we were able to detect early alterations of oesophageal transit during the third week of thoracic RT
Lack of effect of lowering LDL cholesterol on cancer: meta-analysis of individual data from 175,000 people in 27 randomised trials of statin therapy
<p>Background: Statin therapy reduces the risk of occlusive vascular events, but uncertainty remains about potential effects on cancer. We sought to provide a detailed assessment of any effects on cancer of lowering LDL cholesterol (LDL-C) with a statin using individual patient records from 175,000 patients in 27 large-scale statin trials.</p>
<p>Methods and Findings: Individual records of 134,537 participants in 22 randomised trials of statin versus control (median duration 4.8 years) and 39,612 participants in 5 trials of more intensive versus less intensive statin therapy (median duration 5.1 years) were obtained. Reducing LDL-C with a statin for about 5 years had no effect on newly diagnosed cancer or on death from such cancers in either the trials of statin versus control (cancer incidence: 3755 [1.4% per year [py]] versus 3738 [1.4% py], RR 1.00 [95% CI 0.96-1.05]; cancer mortality: 1365 [0.5% py] versus 1358 [0.5% py], RR 1.00 [95% CI 0.93–1.08]) or in the trials of more versus less statin (cancer incidence: 1466 [1.6% py] vs 1472 [1.6% py], RR 1.00 [95% CI 0.93–1.07]; cancer mortality: 447 [0.5% py] versus 481 [0.5% py], RR 0.93 [95% CI 0.82–1.06]). Moreover, there was no evidence of any effect of reducing LDL-C with statin therapy on cancer incidence or mortality at any of 23 individual categories of sites, with increasing years of treatment, for any individual statin, or in any given subgroup. In particular, among individuals with low baseline LDL-C (<2 mmol/L), there was no evidence that further LDL-C reduction (from about 1.7 to 1.3 mmol/L) increased cancer risk (381 [1.6% py] versus 408 [1.7% py]; RR 0.92 [99% CI 0.76–1.10]).</p>
<p>Conclusions: In 27 randomised trials, a median of five years of statin therapy had no effect on the incidence of, or mortality from, any type of cancer (or the aggregate of all cancer).</p>
Emergent versus delayed lithotripsy for obstructing ureteral stones: a cumulative analysis of comparative studies
Objective To analyze the current evidence on the use of ureteroscopy (URS) and extracorporeal shock wave lithotripsy (ESWL) for the management of obstructing ureteral stones in emergent setting.
Methods A systematic literature review was performed up to June 2016 using Pubmed and Ovid databases to identify pertinent studies. The PRISMA criteria were followed for article selection. Separate searches were done using a combinations of several search terms: "laser lithotripsy", "ureteroscopy", "extracorporeal shock wave lithotripsy", "ESWL", "rapid", "immediate", "early", "delayed", "late", "ureteral stones", "kidney stones", "renal stones". Only titles related to emergent/rapid/immediate/early (as viably defined in each study) versus delayed/late treatment of ureteral stones with either URS and/or ESWL were considered for screening. Demographics and operative outcomes were compared between emergent and delayed lithotripsy. RevMan review manager software was used to perform data analysis.
Results Four studies comparing emergent (n = 526) versus delayed (n = 987) URS and six studies comparing emergent (n = 356) versus delayed (n = 355) SWL were included in the analysis. Emergent URS did not show any significant difference in terms of stone-free rate (91.2 versus 90.9%; OR 1.04; CI 0.71, 1.52; p = 0.84), complication rate (8.7% for emergent versus 11.5% for delayed; OR 0.94; CI 0.65, 1.36; p = 0.74) and need for auxiliary procedures (OR 0.85; CI 0.42, 1.7; p = 0.85) when compared to delayed URS. Emergent ESWL was associated with a higher likelihood of stone free status (OR 2.2; CI 1.55, 3.17; p < 0.001) and a lower likelihood of need for auxiliary maneuvers (OR 0.49; CI 0.33, 0.72; p < 0.001) than the delayed procedure. No differences in complication rates were noticed between the emergent and delayed ESWL (p = 0.37).
Conclusions Emergent lithotripsy, either ureteroscopic or extracorporeal, can be offered as an effective and safe treatment for patients with symptomatic ureteral stone. If amenable to ESWL, based on stone and patient characteristics, an emergent approach should be strongly considered. Ureteroscopy in the emergent setting is mostly reserved for distally located stones. The implementation of these therapeutic approaches is likely to be dictated by their availability.info:eu-repo/semantics/publishedVersio
Ultrastructure of the Interlamellar Membranes of the Nacre of the Bivalve Pteria hirundo, Determined by Immunolabelling
The current model for the ultrastructure of the interlamellar membranes of molluscan nacre imply that they consist of a core of aligned chitin fibers surrounded on both sides by acidic proteins. This model was based on observations taken on previously demineralized shells, where the original structure had disappeared. Despite other earlier claims, no direct observations exist in which the different components can be unequivocally discriminated. We have applied different labeling protocols on non-demineralized nacreous shells of the bivalve Pteria. With this method, we have revealed the disposition and nature of the different fibers of the interlamellar membranes that can be observed on the surface of the nacreous shell of the bivalve Pteria hirundo by high resolution scanning electron microscopy (SEM). The minor chitin component consists of very thin fibers with a high aspect ratio and which are seemingly disoriented. Each fiber has a protein coat, which probably forms a complex with the chitin. The chitin-protein-complex fibers are embedded in an additional proteinaceous matrix. This is the first time in which the sizes, positions and distribution of the chitin fibers have been observed in situ.AJOM was financed by a PhD Grant of the FPI program from the Spanish Ministerio de Ciencia e Innovación; TCB's PhD Grant belonged to the FPU Program of the same Ministry. AJOM and AGC were supported by Projects CGL2010-20748-C02-01 and CGL2013-48247-P of the mentioned Ministry, and RNM6433 of the Consejería de Economía, Innovación y Ciencia of the Junta de Andalucía. The European COST Action TD0903 contributed via two Short Term Scientific Missions to AJOM in FM's lab in Dijon
The impact on sleep of a multidisciplinary cognitive behavioural pain management programme: a pilot study
Background: Reduced sleep quality is a common complaint among patients with chronic pain, with 50-80% of patients reporting sleep disturbance. Improvements in pain and quality of life measures have been achieved using a multidisciplinary cognitive behavioural therapy pain management programme (CBT-PMP) that aims to recondition attitudes to pain, and improve patients' self-management of their condition. Despite its high prevalence in patients with chronic pain, there is very limited objective evidence for the effect of this intervention on sleep quality. The primary research objective is to investigate the short-term effect of a multidisciplinary CBTPMP on subjective (measured by Pittsburg Sleep Quality Index) and objective sleep quality (measured by Actigraphy) in patients with chronic pain by comparison with a control group. The secondary objectives will investigate changes in function and mood, and then explore the relationship between objective and subjective sleep quality and physical and psychological outcome measures. Methods/Design: Patients who fulfil the inclusion criteria for attendance on the multidisciplinary CBT-PMP in the Adelaide and Meath Hospital, Tallaght, Dublin and are currently listed on the PMP waiting list will be invited to participate in this pilot study. Potential patients will be screened for sleep disturbance [determined by the Pittsburgh Sleep Quality Index (PSQI)]. Those patients with a sleep disturbance (PSQI >5) will be assigned to either the intervention group (immediate treatment), or control group (deferred treatment, i.e. the PMP they are listed for is more than six months away) based on where they appear on the waiting list. Baseline measures of sleep, function, and mood will be obtained using a combination of self-report questionnaires (the Hospital Anxiety and Depression Scale, the Short Form 36 health survey, the Pittsburgh Sleep Quality Index, the Tampa Scale for Kinesiophobia), and functional outcome measures. Sleep will be measured for seven days using actigraphy (Actiwatch 7). These measures will be repeated after the four week multidisciplinary cognitive behavioural therapy pain management programme, and at a two month follow-up. The waiting list control group will be assessed at baseline, and two months later. Analysis for the primary outcome will include between group differences of subjective and objective sleep parameters from baseline to follow-up using Independent T-tests or Mann-Whitney U tests. The secondary outcomes establishing relationships between the sleep variables and physical and psychological outcome measures will be established using multiple linear regression models. Discussion: This pilot study will evaluate the impact of a multidisciplinary CBT-PMP on both subjective and objective measures of sleep in patients with chronic pain and provide guidance for a larger clinical trial. Trial Registration: Current controlled trial ISRCTN: ISRCTN7491359
Grasping Objects with Environmentally Induced Position Uncertainty
Due to noisy motor commands and imprecise and ambiguous sensory information, there is often substantial uncertainty about the relative location between our body and objects in the environment. Little is known about how well people manage and compensate for this uncertainty in purposive movement tasks like grasping. Grasping objects requires reach trajectories to generate object-fingers contacts that permit stable lifting. For objects with position uncertainty, some trajectories are more efficient than others in terms of the probability of producing stable grasps. We hypothesize that people attempt to generate efficient grasp trajectories that produce stable grasps at first contact without requiring post-contact adjustments. We tested this hypothesis by comparing human uncertainty compensation in grasping objects against optimal predictions. Participants grasped and lifted a cylindrical object with position uncertainty, introduced by moving the cylinder with a robotic arm over a sequence of 5 positions sampled from a strongly oriented 2D Gaussian distribution. Preceding each reach, vision of the object was removed for the remainder of the trial and the cylinder was moved one additional time. In accord with optimal predictions, we found that people compensate by aligning the approach direction with covariance angle to maintain grasp efficiency. This compensation results in higher probability to achieve stable grasps at first contact than non-compensation strategies in grasping objects with directional position uncertainty, and the results provide the first demonstration that humans compensate for uncertainty in a complex purposive task
Genetic aspects of dental disorders
The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.This paper reviews past and present applications of quantitative and molecular genetics to dental disorders. Examples are given relating to craniofacial development (including malocclusion), oral supporting tissues (including periodontal diseases) and dental hard tissues (including defects of enamel and dentine as well as dental caries). Future developments and applications to clinical dentistry are discussed. Early investigations confirmed genetic bases to dental caries, periodontal diseases and malocclusion, but research findings have had little impact on clinical practice. The complex multifactorial aetiologies of these conditions, together with methodological problems, have limited progress until recently. Present studies are clarifying previously unrecognized genetic and phenotypic heterogeneities and attempting to unravel the complex interactions between genes and environment by applying new statistical modelling approaches to twin and family data. linkage studies using highly polymorphic DNA markers are providing a means of locating candidate genes, including quantitative trait loci (QTL). In future, as knowledge increases: it should be possible to implement preventive strategies for those genetically-predisposed individuals who are identified-predisposed individuals who are identified to be at risk.Grant C. Townsend, Michael J. Aldred and P. Mark Bartol
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