Specimen dimensions influence the measurement of material properties in tendon fascicles

Stress, strain and modulus are regularly used to characterize material properties of tissue samples. However, when comparing results from different studies it is evident the reported material properties, particularly failure strains, vary hugely. The aim of our study was to characterize how and why specimen length and cross-sectional area (CSA) appear to influence failure stress, strain and modulus in fascicles from two functionally different tendons. Fascicles were dissected from five rat tails and five bovine foot extensors, their diameters determined by a laser micrometer, and loaded to failure at a range of grip-to-grip lengths. Strain to failure significantly decreased with increasing in specimen length in both rat and bovine fascicles, while modulus increased. Specimen length did not influence failure stress in rat tail fascicles, although in bovine fascicles it was significantly lower in the longer 40 mm specimens compared to 5 and 10 mm specimens. The variations in failure strain and modulus with sample length could be predominantly explained by end-effects. However, it was also evident that strain fields along the sample length were highly variable and notably larger towards the ends of the sample than the mid-section even at distances in excess of 5 mm from the gripping points. Failure strain, stress and modulus correlated significantly with CSA at certain specimen lengths. Our findings have implications for the mechanical testing of tendon tissue: while it is not always possible to control for fascicle length and/or CSA, these parameters have to be taken into account when comparing samples of different dimensions

Asexual expansion of Toxoplasma gondii merozoites is distinct from tachyzoites and entails expression of non-overlapping gene families to attach, invade, and replicate within feline enterocytes

© 2015 Hehl et al.; licensee BioMed Central. Background: The apicomplexan parasite Toxoplasma gondii is cosmopolitan in nature, largely as a result of its highly flexible life cycle. Felids are its only definitive hosts and a wide range of mammals and birds serve as intermediate hosts. The latent bradyzoite stage is orally infectious in all warm-blooded vertebrates and establishes chronic, transmissible infections. When bradyzoites are ingested by felids, they transform into merozoites in enterocytes and expand asexually as part of their coccidian life cycle. In all other intermediate hosts, however, bradyzoites differentiate exclusively to tachyzoites, and disseminate extraintestinally to many cell types. Both merozoites and tachyzoites undergo rapid asexual population expansion, yet possess different effector fates with respect to the cells and tissues they develop in and the subsequent stages they differentiate into. Results: To determine whether merozoites utilize distinct suites of genes to attach, invade, and replicate within feline enterocytes, we performed comparative transcriptional profiling on purified tachyzoites and merozoites. We used high-throughput RNA-Seq to compare the merozoite and tachyzoite transcriptomes. 8323 genes were annotated with sequence reads across the two asexually replicating stages of the parasite life cycle. Metabolism was similar between the two replicating stages. However, significant stage-specific expression differences were measured, with 312 transcripts exclusive to merozoites versus 453 exclusive to tachyzoites. Genes coding for 177 predicted secreted proteins and 64 membrane- associated proteins were annotated as merozoite-specific. The vast majority of known dense-granule (GRA), microneme (MIC), and rhoptry (ROP) genes were not expressed in merozoites. In contrast, a large set of surface proteins (SRS) was expressed exclusively in merozoites. Conclusions: The distinct expression profiles of merozoites and tachyzoites reveal significant additional complexity within the T. gondii life cycle, demonstrating that merozoites are distinct asexual dividing stages which are uniquely adapted to their niche and biological purpose

Intramyocardial hemorrhage and microvascular obstruction after primary percutaneous coronary intervention

Reperfusion may cause intramyocardial hemorrhage (IMH) by extravasation of erythrocytes through severely damaged endothelial walls. The purpose of the study was to evaluate the clinical significance of IMH in relation to infarct size, microvascular obstruction (MVO) and function in patients after primary percutaneous intervention. Forty-five patients underwent cardiovascular MR imaging (CMR) 1 week and 4 months after primary stenting for a first acute myocardial infarction. T2-weighted spin-echo imaging (T2W) was used to assess infarct related edema and IMH, and delayed enhancement (DE) was used to assess infarct size and MVO. Cine CMR was used to assess left ventricular volumes and function at baseline and at 4 months follow-up. In 22 (49%) patients, IMH was detected as areas of attenuated signal in the core of the high signal intensity region on T2W images. Patients with IMH had larger infarcts, higher left ventricular volumes and lower ejection fraction. Contrast-to-noise ratio (CNR) between hyperintense periphery and the hypo-intense core of the T2W ischemic area correlated to peak CKMB, total infarct size and MVO size. Using univariable analysis, CNR predicted ejection fraction at baseline (β = −0.62, P = 0.003) and follow-up (β = −0.84, P < 0.001). However, after multivariable analysis, baseline ejection fraction and presence of MVO were the only parameters that predicted functional changes at follow-up. IMH was found in the majority of patients with MVO after reperfused myocardial infarction. It was closely related to markers of infarct size, MVO and function, but did not have prognostic significance beyond MVO

Genetic and phenotypic analysis of B-cell post-transplant lymphoproliferative disorders provides insights into disease biology

B‐cell post‐transplant lymphoproliferative disorders (PTLD) are classified as early lesions, polymorphic lymphomas (P‐PTLD) and monomorphic lymphomas (M‐PTLD). These morphologic categories are thought to reflect a biologic continuum, although supporting genetic data are lacking. To gain better insights into PTLD pathogenesis, we characterized the phenotypes, immunoglobulin (Ig) gene alterations and non‐Ig gene (BCL6, RhoH/TTF, c‐MYC, PAX5, CIITA, BCL7A, PIM1) mutations of 21 PTLD, including an IM‐like lesion, 8 P‐PTLD and 12 M‐PTLD. Gene expression profile analysis was also performed in 12 cases. All PTLD with clonal Ig rearrangements showed evidence of germinal centre (GC) transit based on the analysis of Ig and BCL6 gene mutations, and 74% had a non‐GC phenotype (BCL6 ± MUM1+). Although surface Ig abnormalities were seen in 6/19 (32%) PTLD, only three showed ‘crippling’ Ig mutations indicating other etiologies for loss of the B‐cell receptor. Aberrant somatic hypermutation (ASHM) was almost exclusively observed in M‐PTLD (8/12 vs. 1/8 P‐PTLD) and all three recurrent cases analysed showed additional mutations in genes targeted by ASHM. Gene expression analysis showed distinct clustering of PTLD compared to B‐cell non‐Hodgkin lymphomas (B‐NHL) without segregation of P‐PTLD from non‐GC M‐PTLD or EBV+ from EBV− PTLD. The gene expression pattern of PTLD appeared more related to that of memory and activated B‐cells. Together, our results suggest that PTLD represent a distinct type of B‐NHL deriving from an antigen experienced B‐cell, whose evolution is associated with accrual of genetic lesions

Parameter identification of the STICS crop model, using an accelerated formal MCMC approach

This study presents a Bayesian approach for the parameters’ identification of the STICS crop model based on the recently developed Differential Evolution Adaptive Metropolis (DREAM) algorithm. The posterior distributions of nine specific crop parameters of the STICS model were sampled with the aim to improve the growth simulations of a winter wheat (Triticum aestivum L.) culture. The results obtained with the DREAM algorithm were initially compared to those obtained with a Nelder-Mead Simplex algorithm embedded within the OptimiSTICS package. Then, three types of likelihood functions implemented within the DREAM algorithm were compared, namely the standard least square, the weighted least square, and a transformed likelihood function that makes explicit use of the coefficient of variation (CV). The results showed that the proposed CV likelihood function allowed taking into account both noise on measurements and heteroscedasticity which are regularly encountered in crop modellingPeer reviewe

'I couldn't even talk to the patient': barriers to communicating with cancer patients as perceived by nursing students

Communication is closely related to safe practice and patient outcomes. Given that most clinicians fall into routines when communicating with patients, it is important to address communication issues early. This study explores Taiwanese nursing students’ experiences of communication with patients with cancer and their families. Senior nursing students who had cared for cancer patients were recruited to participate in focus group interviews. These semi-structured interviews were recorded and transcribed for content analysis. Among the 45 participants, about 36% of them never received any communication training. Up to 76% of the participants stated that their communication with cancer patients was difficult and caused them emotional stress. Subsequent data analysis revealed four themes: dis-engagement, reluctance, regression, and transition. Students’ negative communication experiences were related to the patients’ terminally ill situation; the students’ lack of training, low self-efficacy and power status, poor emotional regulation, and cultural considerations. The findings of this study provide a deeper understanding of nursing students’ communication experiences in oncology settings within the cultural context. Early and appropriate communication training are necessary to help students regulate their emotions and establish effective communication skills. Further studies are needed to examine the relationship among students’ emotional labor, communication skills and outcomes

Detection of regulator genes and eQTLs in gene networks

Genetic differences between individuals associated to quantitative phenotypic traits, including disease states, are usually found in non-coding genomic regions. These genetic variants are often also associated to differences in expression levels of nearby genes (they are "expression quantitative trait loci" or eQTLs for short) and presumably play a gene regulatory role, affecting the status of molecular networks of interacting genes, proteins and metabolites. Computational systems biology approaches to reconstruct causal gene networks from large-scale omics data have therefore become essential to understand the structure of networks controlled by eQTLs together with other regulatory genes, and to generate detailed hypotheses about the molecular mechanisms that lead from genotype to phenotype. Here we review the main analytical methods and softwares to identify eQTLs and their associated genes, to reconstruct co-expression networks and modules, to reconstruct causal Bayesian gene and module networks, and to validate predicted networks in silico.Comment: minor revision with typos corrected; review article; 24 pages, 2 figure

XIPE: the X-ray Imaging Polarimetry Explorer

X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017 but not selected. XIPE is composed of two out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD) filled with a He-DME mixture at their focus and two additional GPDs filled with pressurized Ar-DME facing the sun. The Minimum Detectable Polarization is 14 % at 1 mCrab in 10E5 s (2-10 keV) and 0.6 % for an X10 class flare. The Half Energy Width, measured at PANTER X-ray test facility (MPE, Germany) with JET-X optics is 24 arcsec. XIPE takes advantage of a low-earth equatorial orbit with Malindi as down-link station and of a Mission Operation Center (MOC) at INPE (Brazil).Comment: 49 pages, 14 figures, 6 tables. Paper published in Experimental Astronomy http://link.springer.com/journal/1068

Speech and language therapy for aphasia following stroke

Background  Aphasia is an acquired language impairment following brain damage that affects some or all language modalities: expression and understanding of speech, reading, and writing. Approximately one third of people who have a stroke experience aphasia.  Objectives  To assess the effects of speech and language therapy (SLT) for aphasia following stroke.  Search methods  We searched the Cochrane Stroke Group Trials Register (last searched 9 September 2015), CENTRAL (2015, Issue 5) and other Cochrane Library Databases (CDSR, DARE, HTA, to 22 September 2015), MEDLINE (1946 to September 2015), EMBASE (1980 to September 2015), CINAHL (1982 to September 2015), AMED (1985 to September 2015), LLBA (1973 to September 2015), and SpeechBITE (2008 to September 2015). We also searched major trials registers for ongoing trials including ClinicalTrials.gov (to 21 September 2015), the Stroke Trials Registry (to 21 September 2015), Current Controlled Trials (to 22 September 2015), and WHO ICTRP (to 22 September 2015). In an effort to identify further published, unpublished, and ongoing trials we also handsearched theInternational Journal of Language and Communication Disorders(1969 to 2005) and reference lists of relevant articles, and we contacted academic institutions and other researchers. There were no language restrictions.  Selection criteria  Randomised controlled trials (RCTs) comparing SLT (a formal intervention that aims to improve language and communication abilities, activity and participation) versus no SLT; social support or stimulation (an intervention that provides social support and communication stimulation but does not include targeted therapeutic interventions); or another SLT intervention (differing in duration, intensity, frequency, intervention methodology or theoretical approach).  Data collection and analysis  We independently extracted the data and assessed the quality of included trials. We sought missing data from investigators.  Main results  We included 57 RCTs (74 randomised comparisons) involving 3002 participants in this review (some appearing in more than one comparison). Twenty-seven randomised comparisons (1620 participants) assessed SLT versus no SLT; SLT resulted in clinically and statistically significant benefits to patients' functional communication (standardised mean difference (SMD) 0.28, 95% confidence interval (CI) 0.06 to 0.49, P = 0.01), reading, writing, and expressive language, but (based on smaller numbers) benefits were not evident at follow-up. Nine randomised comparisons (447 participants) assessed SLT with social support and stimulation; meta-analyses found no evidence of a difference in functional communication, but more participants withdrew from social support interventions than SLT. Thirty-eight randomised comparisons (1242 participants) assessed two approaches to SLT. Functional communication was significantly better in people with aphasia that received therapy at a high intensity, high dose, or over a long duration compared to those that received therapy at a lower intensity, lower dose, or over a shorter period of time. The benefits of a high intensity or a high dose of SLT were confounded by a significantly higher dropout rate in these intervention groups. Generally, trials randomised small numbers of participants across a range of characteristics (age, time since stroke, and severity profiles), interventions, and outcomes.  Authors' conclusions  Our review provides evidence of the effectiveness of SLT for people with aphasia following stroke in terms of improved functional communication, reading, writing, and expressive language compared with no therapy. There is some indication that therapy at high intensity, high dose or over a longer period may be beneficial. HIgh-intensity and high dose interventions may not be acceptable to all