A screening approach reveals the influence of mineral coating morphology on human mesenchymal stem cell differentiation

“Biomimetic” inorganic coating on biomaterials has been an active area of research with the aim of providing bioactive surfaces that can regulate cell behavior. Previous studies have demonstrated that human mesenchymal stem cell (hMSC) behavior is differentially regulated by the physical and chemical properties of inorganic mineral coatings, indicating that modulation of mineral properties is potentially important in regulating hMSC behavior. However, the lack of an efficient experimental context, in which to study stem cell behavior on inorganic substrates, has made it difficult to systematically study the effects of specific mineral coating parameters on hMSC behavior. In this study, we developed an efficient experimental platform to screen for the effects of mineral coating morphology on hMSC expansion and differentiation. hMSC expansion on mineral coatings was regulated by the micro-scale morphology of these coatings, with greater expansion on small granule-like coatings when compared to plate-like or net-like coatings. In contrast, hMSC osteogenic differentiation was inversely correlated with cell expansion on mineral coatings indicating that mineral coating morphology was a key parameter that regulates hMSC differentiation. The effect of mineral coating morphology on hMSC behavior underlines the utility of this inorganic screening platform to identify optimal coatings for medical devices and bone tissue engineering applications.     

Negotiating optimum distinctiveness: cognitive tendencies toward primordialism among Mapuche youth

In recent years primordialism, as a model for understanding people's essentialist perceptions of ethnic similarity and difference, has returned to social scientific debates with a new degree of respectability and theoretical rigour. This article provides further evidence for why primordialism is prioritized by ethnic minorities as a cognitive mechanism for maintaining group distinctiveness, drawing on data gathered among indigenous youth in Chile. In the absence of traditional cultural tenets such as indigenous language and knowledge among the majority of the sample, criteria for membership are premised on perceived essentialisms of blood and surname. The result of categorizing others under primordial terms, however, is that it facilitates a space in which individual preferences of ethnic expression and distinctiveness can be negotiated. This brings the dichotomization of primordialism and constructionism under further scrutiny, suggesting that they may be compatible in the everyday practices of social life.     

Skin colour and race as analytic concepts

White working-class people have been portrayed in the media and political discourse as unable to keep pace with the demands associated with living in multicultural Britain. In this article, I shall challenge such representations of white working-class people's attitudes towards racialized ‘others’. To do this I explore the views of the members of a white working-class family to the changing racial composition of their once ethnically homogenous council estate (municipal housing). My ethnographic attention is directed to the connections, affective ties and emotional investments that the members of this family have with the estate and its community, and the ways in which BrAsians become configured in these narratives of belonging. I will show how analytical attention to the connections and attachments that white working-class people form with those whom they identify as ethnic and racial ‘others’ provides an account of white working-class identities that undermines popular representations of ‘them’.     

Numerical assessment of the performance of a scalp‐implantable antenna: Effects of head anatomy and dielectric parameters

We numerically assess the effects of head properties (anatomy and dielectric parameters) on the performance of a scalp‐implantable antenna for telemetry in the Medical Implant Communications Service band (402.0–405.0 MHz). Safety issues and performance (resonance, radiation) are analyzed for an experimentally validated implantable antenna (volume of 203.6 mm³), considering five head models (3‐ and 5‐layer spherical, 6‐, 10‐, and 13‐tissue anatomical) and seven scenarios (variations ± 20% in the reference permittivity and conductivity values). Simulations are carried out at 403.5 MHz using the finite‐difference time‐domain method. Anatomy of the head model around the implantation site is found to mainly affect antenna performance, whereas overall tissue anatomy and dielectric parameters are less significant. Compared to the reference dielectric parameter scenario within the 3‐layer spherical head, maximum variations of ?19.9%, +3.7%, ?55.1%, and ?39.2% are computed in the maximum allowable net input power imposed by the IEEE Std C95.1‐1999 and Std C95.1‐2005 safety guidelines, return loss, and maximum far‐field gain, respectively. Compliance with the recent IEEE Std C95.1‐2005 is found to be almost insensitive to head properties, in contrast with IEEE Std C95.1‐1999. Taking tissue property uncertainties into account is highlighted as crucial for implantable antenna design and performance assessment. Bioelectromagnetics 34:167–179, 2013. © 2012 Wiley Periodicals, Inc.     

Polymorphism in protein tyrosine phosphatase receptor delta is associated with the risk of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common urological malignancy. Our previous study has indicated that the protein tyrosine phosphatase receptor type delta (PTPRD) gene may play a role. To determine the effect of PTPRD genetic polymorphisms on ccRCC occurrence and progression, a total of 377 ccRCC cases and 754 matched controls were enrolled in the study. DNA sequencing and genotyping, and immunohistochemistry were conducted to test the associations of genotypes with ccRCC risk and PTPRD expression level in somatic tissues. The C allele of PTPRD rs2279776 was associated with a higher risk of ccRCC (per allele OR = 1.23, P = 0.03). Patients without distant metastasis at the time of surgery were followed for a median of 33.1 months. Overall survival was not different between different rs2279776 genotype groups (P = 0.30). The C allele was associated with a higher percentage of negative immunostaining in adjacent normal renal tissues (P = 0.02). PTPRD rs2279776 SNP may be a novel genetic risk factor of ccRCC.     

Who Is Too Old for Shift Work? Developing Better Criteria

Demographic and social trends in industrialized countries are expected to lead to increasing numbers of older shift workers, raising concerns about possible health and safety risks. For older night workers, the International Labour Organization has recommended options for transferring to day work or early retirement, but few States have adopted these measures. For commercial air transport pilots, the International Civil Aviation Organization has implemented a series of regulatory measures that could manage the risks associated with aging, including a mandatory retirement age, regular medical assessments for fitness to fly, and limits on the duration of duty and rest. Each of these approaches has strengths and weaknesses. The mandatory retirement age is effectively arbitrary, has been controversial, and was recently increased from 60 to 65 yrs for one member of a two‐person cockpit crew. Medical assessments offer a more individualized approach, but to improve safety, they must address aspects of health and physical or mental function that affect work performance and safety outcomes. The traditional focus has been on cardiovascular risk factors, although cardiac incapacitation is not a cause of accidents in a two‐person cockpit aircraft. On the other hand, while pilot fatigue is an acknowledged cause of accidents, there is currently no requirement to consider issues associated with fatigue or sleep problems in fitness‐to‐fly medical assessments. Older long‐haul pilots show greater sleep fragmentation than their younger colleagues and those in the general population. Sleep becomes more fragmented with increasing age, but the functional significance of this remains unclear. Among younger adults, experimental sleep fragmentation leads to increased sleepiness and degradation of performance and mood. Greater sleep loss is reported by older long‐haul pilots, as well as other older shift workers, compared to younger people working similar duty patterns. Experimental sleep restriction causes a degradation of performance and mood that is cumulative and dose‐dependent. In addition, a recent large‐scale flight simulation study indicates that the duration of sleep obtained by individual pilots is an independent predictor of crew performance in a two‐person cockpit. Based on these considerations, we propose that fatigue and sleep‐related issues should become a standard part of fitness‐for‐work medical assessments, particularly for older shift workers. A multi‐layered approach is proposed, with a routine structured sleep history leading to referral to specialist sleep services where appropriate. Criteria for specialist referral and medical retirement should be related to the workplace risk represented by an older worker. Additional research is needed to develop and validate sleep‐related criteria for assessing fitness for work. For example, a better understanding of the effects of sleep fragmentation on the waking function of older workers might lead to a fragmentation threshold for fitness for work. The potential negative effects of unemployment and early retirement also need to be taken into account when considering the options for managing the occupational health and safety needs of older shift workers.     

Actigraphy: A Means of Assessing Circadian Patterns in Human Activity

–Twenty-three diurnally active (0705–2333), healthy persons between 22 and 54 yrs of age and without history of sleep abnormality were monitored continuously for 120 consecutive hr (five days) by wrist actigraphy. Circadian rhythms of high amplitude were detected by cosinor analysis for each participant and for the groups of 10 males and 13 females with the average span of heightened activity timed between ～1330 and 1605. The circadian peak-trough difference in wrist movement was marked, equalling aproximately 75% of the 24-hr mean level. In 19 of 23 participants, the 24-hr mean of wrist activity varied between 140–180 movements/min, with four persons exhibiting lesser means of 110–140 movements/min. With respect to the daytime span of activity, the mean wrist movement of individual participants ranged from 155–265 movements/min, with the majority (20/23) varying between 185–245 movements/min. During nocturnal sleep the mean wrist activity level was quite low, varying between individuals from 5 to 25 movements/min for 21 of 23 persons. Wrist actigraphy proved to be well-accepted and was a most reliable means of monitoring aspects of body movement during activity and sleep in ambulatory persons adhering to usual life habits and pursuits.     

Porte sonde motorisé pour une télé-échographie abdominale en temps différé : étude de faisabilité

PurposeDesign a system of delayed telesonography between expert center and isolated site where there is no sonographer.Materials and methodsA motorized probe holder printing a movement of TILT (± 40°) to any 2D echograph probe available in an isolated site, allows a non-sonographer to capture the patients’ whole organ images. This volume of images is sent to the expert center via internet. The video sequence is decomposed into images in the JPEG format by the software VirtualDub. A post-processing software (ECHO-CNES) allows the expert to find the incidences necessary for the diagnosis. This system has been tested on 50 patients at the CHU Trousseau (Tours, France).ResultsOrgans investigated were liver, portal vein, gall-bladder, kidneys (right and left) and spleen. The acquisition time of the volumes of images was 4 min maximum and allowed to reconstruct images necessary for the diagnosis in 80% of the cases. Scanning duration lasted 4 s on average; processing duration of the volume of images lasted approximately 15 min.ConclusionThis system is in validation in real situation in Togo with the aim of its generalization for medical care according to the obtained results.     

综合设计性实验在医学微生物实验教学中的应用

在医学微生物实验教学中选择合适的时机、安排合理的实验内容来开展综合设计性实验有效的调动了学生的学习积极性、培养了学生的临床思维能力,为培养新型医学人才奠定了基础.     

High plant species richness indicates management-related disturbances rather than the conservation status of forests

There is a wealth of smaller-scale studies on the effects of forest management on plant diversity. However, studies comparing plant species diversity in forests with different management types and intensity, extending over different regions and forest stages, and including detailed information on site conditions are missing. We studied vascular plants on 1500 20 m × 20 m forest plots in three regions of Germany (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin). In all regions, our study plots comprised different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests, which resulted from clear cutting or shelterwood logging), various stand ages, site conditions, and levels of management-related disturbances. We analyzed how overall richness and richness of different plant functional groups (trees, shrubs, herbs, herbaceous species typically growing in forests and herbaceous light-demanding species) responded to the different management types. On average, plant species richness was 13% higher in age-class than in unmanaged forests, and did not differ between deciduous age-class and selection forests. In age-class forests of the Schwäbische Alb and Hainich-Dün, coniferous stands had higher species richness than deciduous stands. Among age-class forests, older stands with large quantities of standing biomass were slightly poorer in shrub and light-demanding herb species than younger stands. Among deciduous forests, the richness of herbaceous forest species was generally lower in unmanaged than in managed forests, and it was even 20% lower in unmanaged than in selection forests in Hainich-Dün. Overall, these findings show that disturbances by management generally increase plant species richness. This suggests that total plant species richness is not suited as an indicator for the conservation status of forests, but rather indicates disturbances.