DXA predictions of human femoral mechanical properties depend on the load configuration

The aim of this study was to evaluate the ability of dual energy X-rays absorptiometry (DXA) areal bone mineral density (aBMD) measured in different regions of the proximal part of the human femur for predicting the mechanical properties of matched proximal femora tested in two different loading configurations. 36 pairs of fresh frozen femora were DXA scanned and tested until failure in two loading configurations: a fall on the side or a one-legged standing. The ability of the DXA output from four different regions of the proximal femur in predicting the femoral mechanical properties was measured and compared for the two loading scenarios. The femoral neck DXA BMD was best correlated to the femoral ultimate force for both configurations and predicted significantly better femoral failure load (R2=0.80 vs. R2=0.66, P<0.05) when simulating a side than when simulating a standing configuration. Conversely, the work to failure was predicted similarly for both loading configurations (R2=0.54 vs. R2=0.53, P>0.05). Therefore, neck BMD should be considered as one of the key factors for discriminating femoral fracture risk in vivo. Moreover, the better predictive ability of neck BMD for femoral strength if tested in a fall compared to a one-legged stance configuration suggests that DXA's clinical relevance may not be as high for spontaneous femoral fractures than for fractures associated to a fall.

Mapping material distribution in a heterogeneous sand tank by image analysis

Water flow and solute transport through soils are strongly influenced by the spatial arrangement of soil materials with different hydraulic and chemical properties. Knowing the specific or statistical arrangement of these materials is considered as a key toward improved predictions of solute transport. Our aim was to obtain two-dimensional material maps from photographs of exposed profiles. We developed a segmentation and classification procedure and applied it to the images of a very heterogeneous sand tank, which was used for a series of flow and transport experiments. The segmentation was based on thresholds of soil color, estimated from local median gray values, and of soil texture, estimated from local coefficients of variation of gray values. Important steps were the correction of inhomogeneous illumination and reflection, and the incorporation of prior knowledge in filters used to extract the image features and to smooth the results morphologically. We could check and confirm the success of our mapping by comparing the estimated with the designed sand distribution in the tank. The resulting material map was used later as input to model flow and transport through the sand tank. Similar segmentation procedures may be applied to any high-density raster data, including photographs or spectral scans of field profiles.

Social Meets Molecular: Combining Phylogenetic and Latent Class Analyses to Understand HIV-1 Transmission in Switzerland

Switzerland has a complex human immunodeficiency virus (HIV) epidemic involving several populations. We examined transmission of HIV type 1 (HIV-1) in a national cohort study. Latent class analysis was used to identify socioeconomic and behavioral groups among 6,027 patients enrolled in the Swiss HIV Cohort Study between 2000 and 2011. Phylogenetic analysis of sequence data, available for 4,013 patients, was used to identify transmission clusters. Concordance between sociobehavioral groups and transmission clusters was assessed in correlation and multiple correspondence analyses. A total of 2,696 patients were infected with subtype B, 203 with subtype C, 196 with subtype A, and 733 with recombinant subtypes (mainly CRF02_AG and CRF01_AE). Latent class analysis identified 8 patient groups. Most transmission clusters of subtype B were shared between groups of gay men (groups 1-3) or between the heterosexual groups "heterosexual people of lower socioeconomic position" (group 4) and "injection drug users" (group 8). Clusters linking homosexual and heterosexual groups were associated with "older heterosexual and gay people on welfare" (group 5). "Migrant women in heterosexual partnerships" (group 6) and "heterosexual migrants on welfare" (group 7) shared non-B clusters with groups 4 and 5. Combining approaches from social and molecular epidemiology can provide insights into HIV-1 transmission and inform the design of prevention strategies.

Feather-pecking response of laying hens to feather and cellulose-based rations fed during rearing.

Recent studies in laying hens have shown that feather peckers eat more feathers than nonpeckers. We hypothesized that food pellets containing feathers would decrease the birds' appetite for feathers and thereby also decrease feather pecking. To separate the effect of feathers from that of insoluble fiber per se, additional control groups were fed pellets containing similar amounts of cellulose. Sixty (experiment 1) and 180 (experiment 2) 1-d-old Lohmann-Selected Leghorn birds were divided into 12 groups of 5 (experiment 1) and 15 (experiment 2) birds, respectively, and kept on slatted floors. During the rearing period, 4 groups each had ad libitum access to either a commercial pelleted diet, a pelleted diet containing 5% (experiment 1) or 10% (experiment 2) of chopped feathers, respectively, or a pelleted diet containing 5% (experiment 1) or 10% (experiment 2) of cellulose, respectively. In the consecutive laying period, all groups received a commercial pelleted diet. In experiment 1, feather pecking was recorded weekly from wk 5 to wk 16. In the laying period, observations were made in wk 18, 20, 22, 23, 24, 25, 26, 27, 28, and 30. In experiment 2, feather pecking was recorded weekly from wk 5 to 11, in wk 16 to wk 18, and in wk 20 and 21. At the end of the rearing period, plumage condition per individual hen was scored. Scores from 1 (denuded) to 4 (intact) were given for each of 6 body parts. The addition of 10% of feathers to the diet reduced the number of severe feather-pecking bouts (P < 0.0129) and improved plumage condition of the back area (P < 0.001) significantly compared with control diets. The relationship between feather pecking/eating and the gastrointestinal consequences thereof, which alter feather pecking-behavior, are unclear. Understanding this relationship might be crucial for understanding the causation of feather pecking in laying hens.

Genomic heterogeneity of small ruminant lentiviruses detected by PCR

In order to detect a large spectrum of small ruminant lentiviruses, primers for PCR were chosen in conserved parts of the LTR and GAG genes of Icelandic Visna virus 1514 and of the POL gene of caprine arthritis-encephalitis virus. This set of primers was tested in six different caprine arthritis-encephalitis virus (CAEV)- and Maedi-Visna virus isolates of Dutch, American and Swiss origin. The LTR primers allowed the detection of the corresponding fragments of all isolates. The GAG primers allowed amplification of the corresponding fragments of all but the Swiss Maedi-Visna virus strain OLV. Using the POL primers, one Maedi-Visna- and two caprine arthritis-encephalitis virus strains were detected after one round of amplification. Sequencing of the GAG and POL amplification products and comparison to Icelandic Visna virus and CAEV strain CO revealed total heterogeneity of 38% for the GAG- and 28% for the POL fragment. The virus strains studied fall into two groups which are more closely related to one another than to Icelandic Visna virus.

Defence on demand: mechanisms behind optimal defence patterns

Background The optimal defence hypothesis (ODH) predicts that tissues that contribute most to a plant's fitness and have the highest probability of being attacked will be the parts best defended against biotic threats, including herbivores. In general, young sink tissues and reproductive structures show stronger induced defence responses after attack from pathogens and herbivores and contain higher basal levels of specialized defensive metabolites than other plant parts. However, the underlying physiological mechanisms responsible for these developmentally regulated defence patterns remain unknown. Scope This review summarizes current knowledge about optimal defence patterns in above- and below-ground plant tissues, including information on basal and induced defence metabolite accumulation, defensive structures and their regulation by jasmonic acid (JA). Physiological regulations underlying developmental differences of tissues with contrasting defence patterns are highlighted, with a special focus on the role of classical plant growth hormones, including auxins, cytokinins, gibberellins and brassinosteroids, and their interactions with the JA pathway. By synthesizing recent findings about the dual roles of these growth hormones in plant development and defence responses, this review aims to provide a framework for new discoveries on the molecular basis of patterns predicted by the ODH. Conclusions Almost four decades after its formulation, we are just beginning to understand the underlying molecular mechanisms responsible for the patterns of defence allocation predicted by the ODH. A requirement for future advances will be to understand how developmental and defence processes are integrated.

Sediments of Lake Vens (SW European Alps, France) record large-magnitude earthquake events

We studied sediment cores from Lake Vens (2,327 m asl), in the Tinée Valley of the SW Alps, to test the paleoseismic archive potential of the lake sediments in this particularly earthquake-sensitive area. The historical earthquake catalogue shows that moderate to strong earthquakes, with intensities of IX–X, have impacted the Southern Alps during the last millennium. Sedimentological (X-ray images, grain size distribution) and geochemical (major elements and organic matter) analyses show that Lake Vens sediments consist of a terrigenous, silty material (minerals and organic matter) sourced from the watershed and diatom frustules. A combination of X-ray images, grain-size distribution, major elements and magnetic properties shows the presence of six homogenite-type deposits interbedded in the sedimentary background. These sedimentological features are ascribed to sediment reworking and grain sorting caused by earthquake-generated seiches. The presence of microfaults that cross-cut the sediment supports the hypothesis of seismic deposits in this system. A preliminary sediment chronology is provided by 210Pb measurement and AMS 14C ages. According to the chronology, the most recent homogenite events are attributable to damaging historic earthquakes in AD 1887 (Ligure) and 1564 (Roquebillière). Hence, the Lake Vens sediment recorded large-magnitude earthquakes in the region and permits a preliminary estimate of recurrence time for such events of ~400 years.

A novel regulatory macrophage induced by a helminth molecule instructs IL-10 in CD4+ T cells and protects against mucosal inflammation

Immunomodulation is a common feature of chronic helminth infections and mainly attributed to the secretion of bioactive molecules, which target and modify host immune cells. In this study, we show that the helminth immunomodulator AvCystatin, a cysteine protease inhibitor, induces a novel regulatory macrophage (Mreg; AvCystatin-Mreg), which is sufficient to mitigate major parameters of allergic airway inflammation and colitis in mice. A single adoptive transfer of AvCystatin-Mreg before allergen challenge suppressed allergen-specific IgE levels, the influx of eosinophils into the airways, local and systemic Th2 cytokine levels, and mucus production in lung bronchioles of mice, whereas increasing local and systemic IL-10 production by CD4(+) T cells. Moreover, a single administration of AvCystatin-Mreg during experimentally induced colitis strikingly reduced intestinal pathology. Phenotyping of AvCystatin-Mreg revealed increased expression of a distinct group of genes including LIGHT, sphingosine kinase 1, CCL1, arginase-1, and costimulatory molecules, CD16/32, ICAM-1, as well as PD-L1 and PD-L2. In cocultures with dendritic cells and CD4(+) T cells, AvCystatin-Mreg strongly induced the production of IL-10 in a cell-contact-independent manner. Collectively, our data identify a specific suppressive macrophage population induced by a single parasite immunomodulator, which protects against mucosal inflammation.

ABCB5 Identifies Immunoregulatory Dermal Cells

Cell-based strategies represent a new frontier in the treatment of immune-mediated disorders. However, the paucity of markers for isolation of molecularly defined immunomodulatory cell populations poses a barrier to this field. Here, we show that ATP-binding cassette member B5 (ABCB5) identifies dermal immunoregulatory cells (DIRCs) capable of exerting therapeutic immunoregulatory functions through engagement of programmed cell death 1 (PD-1). Purified Abcb5(+) DIRCs suppressed T cell proliferation, evaded immune rejection, homed to recipient immune tissues, and induced Tregs in vivo. In fully major-histocompatibility-complex-mismatched cardiac allotransplantation models, allogeneic DIRCs significantly prolonged allograft survival. Blockade of DIRC-expressed PD-1 reversed the inhibitory effects of DIRCs on T cell activation, inhibited DIRC-dependent Treg induction, and attenuated DIRC-induced prolongation of cardiac allograft survival, indicating that DIRC immunoregulatory function is mediated, at least in part, through PD-1. Our results identify ABCB5(+) DIRCs as a distinct immunoregulatory cell population and suggest promising roles of this expandable cell subset in cellular immunotherapy.

Impact of different magnification levels on visual caries detection with ICDAS

OBJECTIVES The aim of this in vitro study was to examine the effect of different levels of magnification on the accuracy and reliability of visual caries detection using ICDAS criteria. METHODS Occlusal surfaces of 100 extracted molars were assessed by 14 examiners (3rd and the 4th year dental students and dentists) using no magnification aids, a 2.5× Galilean loupe, a 4.5× Keplerian loupe, or a surgical microscope with 10× magnification. The assessments were repeated on a different day. Sensitivity, specificity, AUC and reliabilities were calculated according to the gold standard of histology. RESULTS We found that with increasing magnification, the number of surfaces rated as "sound" (ICDAS code 0) decreased, while the number of surfaces with a localized enamel breakdown (ICDAS code 3) increased. While the sensitivities increased, the values of the specificities decreased to an unacceptably low level irrespective of the clinical experience of the examiners. CONCLUSIONS ICDAS seems to be optimized for natural vision up to 2.0× magnification and not for high magnifications. The use of powerful magnification in visual caries detection involves the risk of unnecessary and premature invasive treatment. CLINICAL SIGNIFICANCE This paper discusses when it does and does not make sense to use magnification devices for visual caries detection using ICDAS criteria. Strong magnifications should be refrained from for this purpose.

Trends in mean and extreme precipitation in the Mount Kenya region from observations and reanalyses

Land and water management in semi-arid regions requires detailed information on precipitation distribution, including extremes, and changes therein. Such information is often lacking. This paper describes statistics of mean and extreme precipitation in a unique data set from the Mount Kenya region, encompassing around 50 stations with at least 30 years of data. We describe the data set, including quality control procedures and statistical break detection. Trends in mean precipitation and extreme indices calculated from these data for individual rainy seasons are compared with corresponding trends in reanalysis products. From 1979 to 2011, mean precipitation decreased at 75% of the stations during the ‘long rains’ (March to May) and increased at 70% of the stations during the ‘short rains’ (October to December). Corresponding trends are found in the number of heavy precipitation days, and maximum of consecutive 5-day precipitation. Conversely, an increase in consecutive dry days within both main rainy seasons is found. However, trends are only statistically significant in very few cases. Reanalysis data sets agree with observations with respect to interannual variability, while correlations are considerably lower for monthly deviations (ratios) from the mean annual cycle. While some products well reproduce the rainfall climatology and some the spatial trend pattern, no product reproduces both.