Manufacture of Multilayered Artificial Cell Membranes through Sequential Bilayer Deposition on Emulsion Templates

Efforts to manufacture artificial cells that replicate the architectures, processes and behaviours of biological cells are rapidly increasing. Perhaps the most commonly reconstructed cellular structure is the membrane, through the use of unilamellar vesicles as models. However, many cellular membranes, including bacterial double membranes, nuclear envelopes, and organelle membranes, are multilamellar. Due to a lack of technologies available for their controlled construction, multilayered membranes are not part of the repertoire of cell-mimetic motifs used in bottom-up synthetic biology. To address this, we developed emulsion-based technologies that allow cell-sized multilayered vesicles to be produced layer-by-layer, with compositional control over each layer, thus enabling studies that would otherwise remain inaccessible. We discovered that bending rigidities scale with the number of layers and demonstrate inter-bilayer registration between coexisting liquid–liquid domains. These technologies will contribute to the exploitation of multilayered membrane structures, paving the way for incorporating protein complexes that span multiple bilayers.     

Association of serum alkaline phosphatase and bone mineral density in maintenance hemodialysis patients

Recent studies indicate that serum alkaline phosphatase (AlkPhos), a surrogate of high turnover bone disease, is associated with coronary artery calcification and death risk in maintenance hemodialysis (MHD) patients. The association between AlkPhos and bone mineral density (BMD) is not well studied. We studied the association between AlkPhos and dual‐energy X‐ray absorptiometry‐assessed BMD in a group of MHD patients in Southern California. In 154 MHD patients, aged 55.3 ± 13.6 years, including 42% women, 38% Hispanics, 42% African Americans, and 55% diabetics, the mean serum AlkPhos was 121 ± 63 U/L (median: 101, Q_25–75: 81–141); 36% had AlkPhos≥120 U/L and 50% had a total T‐score≤?1. Whereas the total BMD did not correlate with age (r=0.01, P=0.99) or body mass index (r=0.10, P=0.22), it correlated negatively with AlkPhos (r=?0.25, P=0.002), including after multivariate adjustment (r=?0.24, P=0.003). The proportion of patients with a high coronary artery calcification score>400 was incrementally higher across worsening BMD tertiles (P trend=0.04). The BMD was significantly worse in MHD patients with serum AlkPhos≥120 U/L compared with <120 U/L (1.01 ± 0.016 vs. 1.08 ± 0.013 g/cm², respectively, P<0.001). The multivariate adjusted odds ratio of AlkPhos≥120 U/L for having a total T‐score相似文献   

The conductivity modulation of silicon samples under dark and gamma irradiation conditions

Dark conductivity of silicon wafers has been measured as a function of doping levels, sample’s geometry, and under gamma irradiation conditions.It has been shown that measurements of samples conductivity under different operating conditions can be used as an efficient method for material quality evaluation. In addition, gamma irradiation gives future information on Si-wafer quality, where it can effectively influence the material properties.The induced change in conductivity is discussed following the mathematical difference of conductivity modulation mode. Using this model conductivity measurements could be considered as a good and simple technique for determining the silicon quality and for further development in silicon processing.     

Solar energy education - a viable pathway for sustainable development

The growing consumption of limited reserves of fossil fuels and their impact to the environment have raised global interest in harnessing solar energy. Proper knowledge of solar energy is lacking in many levels of society. Recently, the Energy Research Institute (ERI) of King Abdulaziz City for Science and Technology (KACST) have conducted a survey on the availability of solar energy education program around the world. It has been observed that a considerable amount of work has been done for developing solar energy technologies but relatively little attention has been paid on the role of solar energy education. This paper gives an overview of the current status of solar education program available around the globe and it also highlights the importance of the energy information network for solar education program.     

Revisiting the association between altitude and mortality in dialysis patients

It was recently reported that residential altitude is inversely associated with all‐cause mortality among incident dialysis patients; however, no adjustment was made for key case‐mix and laboratory variables. We re‐examined this question in a contemporary patient database with comprehensive clinical and laboratory data. In a contemporary 8‐year cohort of 144,892 maintenance dialysis patients from a large dialysis organization, we examined the relationship between residential altitude and all‐cause mortality. Using data from the US Geological Survey, the average residential altitudes per approximately 43,000 US zip codes were compiled and linked to the residential zip codes of each patient. Mortality risks for these patients were estimated by Cox proportional hazard ratios. The study population's mean ± standard deviation age was 61 ± 15 years. Forty‐five percent of patients were women, and 57% of patients had diabetes. In fully adjusted analysis, those residing in the highest altitude strata (≥6000 ft) had a lower all‐cause mortality risk in fully adjusted analyses: death hazard ratio: 0.92 (95% confidence interval, 0.86–0.99), as compared with patients in the reference group (<250 ft). Residential altitude is inversely associated in all‐cause mortality risk in maintenance dialysis patients notwithstanding the unknown and unmeasured confounders.     

Crystallographic Parameters and Band Gap of CdSxSe1-x Mixed Crystals

Crystals of CdSxSe1-x alloys have been grown from the vapour phase. Some of the physical properties, such as lattice parameters, crystal structure and x-rays data of CdSxSe1-x alloys were determined using x-ray diffractometry. X-ray diffractometry has shown that CdS-CdSe mixed crystals had the wurtzite structure for all compositions between CdS and CdSe. The lattice parameters （both a and c） were found to show a linear dependence with composition. The dependence of the lattice parameters of a and c on composition can be expressed as： a（x） = 4.165 ＋ 0.16x; c（x） = 6.713 ＋ 0.27x. The variation of band gap with composition was determined for these samples from optical absorption measurements, which showed that the band gap varied smoothly and monotonically, but not linearly over the composition range typical results were found between 2.42-1.74 eV at room temperature.     

Comparing the Fried frailty phenotype versus the Veterans Affairs frailty index among dialysis dependent patients

Introduction

Frailty in dialysis patients is a modifiable disease state which can increase mortality if left untreated but remains underdiagnosed as frailty evaluations can be arduous or time consuming. We evaluate the agreement between a clinical frailty construct (Fried frailty phenotype, FFP) against and an electronic health record-based Veterans Affairs Frailty Index (VAFI) and their association with mortality.

Methods

A r etrospective cohort analysis of 764 participants from the ACTIVE/ADIPOSE study was performed. Frailty as measured by VAFI and FFP was obtained and Kappa statistic estimating concordance between the two scores were calculated. Differences in mortality risk were analyzed according to presence or absence of frailty.

Findings

When assessing agreement between the VAFI and FFP, the kappa statistic was 0.09 (95% confidence interval [CI] 0.02–0.16) suggesting a low level of agreement. Frailty was independently associated with higher mortality risk (hazards ratio [HR] 1.40–1.42 in fully adjusted models depending upon frailty construct). Discordantly frail patients by construct had a higher risk of mortality though this was not statistically significant after adjustment. However, concordantly frail patients had much higher mortality risk compared to concordantly nonfrail (adjusted HR 2.08, 95% CI 1.44–3.01).

Discussion

Poor agreement between constructs is likely reflective of the multifactorial definition of frailty. While further longitudinal studies are needed to determine if the VAFI would be beneficial in the reassessment of frailty, it may be beneficial as a cue for further frailty testing (e.g., with FFP) with the combination of multiple frail constructs providing improved prognostic information.