Kinetically-controlled thin-film growth of layered β\beta- and γ−\gamma-Nax_{x}CoO2_{2} cobaltate

We report growth characteristics of epitaxial $\beta$-Na$_{0.6}$CoO$_{2}$ and $\gamma$-Na$_{0.7}$CoO$_{2}$ thin films on (001) sapphire substrates grown by pulsed-laser deposition. Reduction of deposition rate could change structure of Na$_{x}$CoO$_{2}$ thin film from $\beta$-phase with island growth mode to $\gamma$-phase with layer-by-layer growth mode. The $\gamma$-Na$_{0.7}$CoO$_{2}$ thin film exhibits spiral surface growth with multiterraced islands and highly crystallized texture compared to that of the $\beta$-Na$_{0.6}$CoO$_{2}$ thin film. This heterogeneous epitaxial film growth can give opportunity of strain effect of physical properties and growth dynamics of Na$_{x}$CoO$_{2}$ as well as subtle nature of structural change.Comment: accepted for publication in Applied Physics Letter

Lemnaceae and Orontiaceae Are Phylogenetically and Morphologically Distinct from Araceae

Duckweeds comprise a distinctive clade of pleustophytic monocots that traditionally has been classified as the family Lemnaceae. However, molecular evidence has called into question their phylogenetic independence, with some authors asserting instead that duckweeds should be reclassified as subfamily Lemnoideae of an expanded family Araceae. Although a close phylogenetic relationship of duckweeds with traditional Araceae has been supported by multiple studies, the taxonomic disposition of duckweeds must be evaluated more critically to promote nomenclatural stability and utility. Subsuming duckweeds as a morphologically incongruent lineage of Araceae effectively eliminates the family category of Lemnaceae that has been widely used for many years. Instead, we suggest that Araceae subfamily Orontioideae should be restored to family status as Orontiaceae, which thereby would enable the recognition of three morphologically and phylogenetically distinct lineages: Araceae, Lemnaceae, and Orontiaceae

Anomalous field-dependent specific heat in charge-ordered Pr1−x_{1-x}Cax_xMnO3_3 and La0.5_{0.5}Ca0.5_{0.5}MnO3_3

We report low temperature specific heat measurements of Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ ($0.3\leq x \leq 0.5$) and La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ with and without applied magnetic field. An excess specific heat, $C^{\prime}(T)$, of non-magnetic origin associated with charge ordering is found for all the samples. A magnetic field sufficient to induce the transition from the charge-ordered state to the ferromagnetic metallic state does not completely remove the $C^{\prime}$ contribution. This suggests that the charge ordering is not completely destroyed by a "melting" magnetic field. In addition, the specific heat of the Pr$_{1-x}$Ca$_{x}$MnO$_{3}$ compounds exhibit a large contribution linear in temperature ($\gamma T$) originating from magnetic and charge disorder.Comment: submitted to PRL 5 pages, 3 figures include

All-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers

We present an all-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers integrated into a microfluidic chip. The chip is entirely made from polymers, enabling the use of the devices as low-cost disposables. The microgoblet cavities feature quality factors exceeding 105 and are fabricated from poly(methyl methacrylate) (PMMA) using spin-coating, mask-based optical lithography, wet chemical etching, and thermal reflow. In contrast to silica-based microtoroid resonators, this approach replaces technically demanding vacuum-based dry etching and serial laser-based reflow techniques by solution-based processing and parallel thermal reflow. This enables scaling to large-area substrates, and hence significantly reduces device costs. Moreover, the resonators can be fabricated on arbitrary substrate materials, e.g., on transparent and flexible polymer foils. Doping the microgoblets with the organic dye pyrromethene 597 transforms the passive resonators into lasers. Devices have lasing thresholds below 0.6 nJ per pulse and can be efficiently pumped via free-space optics using a compact and low-cost green laser diode. We demonstrate that arrays of microgoblet lasers can be readily integrated into a state-of-the-art microfluidic chip replicated via injection moulding. In a proof-of-principle experiment, we show the viability of the lab-on-a-chip via refractometric sensing, demonstrating a bulk refractive index sensitivity (BRIS) of 10.56 nm per refractive index unit. © The Royal Society of Chemistry 2015

Structural and doping effects in the half-metallic double perovskite A2A_2CrWO6_6

he structural, transport, magnetic and optical properties of the double perovskite $A_2$CrWO$_6$ with $A=\text{Sr, Ba, Ca}$ have been studied. By varying the alkaline earth ion on the $A$ site, the influence of steric effects on the Curie temperature $T_C$ and the saturation magnetization has been determined. A maximum $T_C=458$ K was found for Sr$_2$CrWO$_6$ having an almost undistorted perovskite structure with a tolerance factor $f\simeq 1$. For Ca$_2$CrWO$_6$ and Ba$_2$CrWO$_6$ structural changes result in a strong reduction of $T_C$. Our study strongly suggests that for the double perovskites in general an optimum $T_C$ is achieved only for $f \simeq 1$, that is, for an undistorted perovskite structure. Electron doping in Sr$_2$CrWO$_6$ by a partial substitution of Sr$^{2+}$ by La$^{3+}$ was found to reduce both $T_C$ and the saturation magnetization $M_s$. The reduction of $M_s$ could be attributed both to band structure effects and the Cr/W antisites induced by doping. Band structure calculations for Sr$_2$CrWO$_6$ predict an energy gap in the spin-up band, but a finite density of states for the spin-down band. The predictions of the band structure calculation are consistent with our optical measurements. Our experimental results support the presence of a kinetic energy driven mechanism in $A_2$CrWO$_6$, where ferromagnetism is stabilized by a hybridization of states of the nonmagnetic W-site positioned in between the high spin Cr-sites.Comment: 14 pages, 10 figure

Genetic structure of the protist Physarum albescens (Amoebozoa) revealed by multiple markers and genotyping by sequencing

Myxomycetes are terrestrial protists with many presumably cosmopolitan species dispersing via airborne spores. A truly cosmopolitan species would suffer from outbreeding depression hampering local adaptation, while locally adapted species with limited distribution would be at a higher risk of extinction in changing environments. Here, we investigate intraspecific genetic diversity and phylogeography of Physarum albescens over the entire Northern Hemisphere. We sequenced 324 field collections of fruit bodies for 1-3 genetic markers (SSU, EF1A, COI) and analysed 98 specimens with genotyping by sequencing. The structure of the three-gene phylogeny, SNP-based phylogeny, phylogenetic networks, and the observed recombination pattern of three independently inherited gene markers can be best explained by the presence of at least 18 reproductively isolated groups, which can be seen as cryptic species. In all intensively sampled regions and in many localities, members of several phylogroups coexisted. Some phylogroups were found to be abundant in only one region and completely absent in other well-studied regions, and thus may represent regional endemics. Our results demonstrate that the widely distributed myxomycete species Ph. albescens represents a complex of at least 18 cryptic species, and some of these seem to have a limited geographical distribution. In addition, the presence of groups of presumably clonal specimens suggests that sexual and asexual reproduction coexist in natural populations of myxomycetes

Definitions and Standardization of a New Grading Scheme for Eyelid Contour Abnormalities after Trichiasis Surgery

Approximately 8 million individuals worldwide suffer from trichiasis, a condition characterized by in-turned lashes that rub against the eye. Trichiasis is caused by repeated or prolonged ocular infection with Chlamydia trachomatis. Surgery is available to correct in-turned lashes. In most programmatic and research settings, the primary determinant of surgical success is whether or not lashes are touching the globe post-operatively. However, other surgical outcomes such as the contour of the eyelid are also important. Yet, no standard method for evaluating and reporting this outcome has been defined. In this study, we developed and tested a grading system for evaluating the severity of eyelid contour abnormalities after surgery using photographs of eyelids six weeks post-operatively. We found good agreement across photograph graders and also between field and photograph grades. This system should be useful in helping to standardize reporting of this outcome

Multilevel analysis of systolic blood pressure and ACE gene I/D polymorphism in 438 Swedish families – a public health perspective

BACKGROUND: Individuals belonging to the same family share a number of genetic as well as environmental circumstances that may condition a common SBP level. Among the genetic factors, the angiotensin converting enzyme (ACE) gene I/D polymorphism appears as a possible candidate as it might influence both SBP and the pharmacological effect of ACE inhibitors. We aimed to combine genetic epidemiology with public health ideas concerning life-course and multilevel epidemiology in order to understand the role of familial factors regarding individual SBP. METHODS: We applied multilevel regression analysis on 1926 individuals nested within 438 families from South Sweden. Modelling familial SBP variance as a function of age and use of ACE inhibitors we calculates a variance partition coefficient and the proportional change in familial SBP variance attributable to differences in ACE gene I/D polymorphism RESULTS: Our results suggest the existence of genetic or environmental circumstances that produce a considerable familial clustering of SBP, especially among individuals using ACE-inhibitors. However, ACE gene I/D polymorphism seems to play a minor role in this context. In addition, familial factors – genetic, environmental or their interaction – shape SBP among non-users of ACE inhibitors but their effect is expressed later in the life-course. CONCLUSION: Strategies directed to prevent hypertension should be launched in younger rather than in older ages and both prevention of hypertension and its treatment with ACE inhibitors should be focused on families rather than on individuals

The outcome of trachomatous trichiasis surgery in Ethiopia: risk factors for recurrence.

BACKGROUND: Over 1.2 million people are blind from trachomatous trichiasis (TT). Lid rotation surgery is the mainstay of treatment, but recurrence rates can be high. We investigated the outcomes (recurrence rates and other complications) of posterior lamellar tarsal rotation (PLTR) surgery, one of the two most widely practised TT procedures in endemic settings. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a two-year follow-up study of 1300 participants who had PLTR surgery, conducted by one of five TT nurse surgeons. None had previously undergone TT surgery. All participants received a detailed trachoma eye examination at baseline and 6, 12, 18 and 24 months post-operatively. The study investigated the recurrence rates, other complications and factors associated with recurrence. Recurrence occurred in 207/635 (32.6%) and 108/641 (16.9%) of participants with pre-operative major (>5 trichiatic lashes) and minor (5 lashes (major recurrence). Recurrence was greatest in the first six months after surgery: 172 cases (55%) occurring in this period. Recurrence was associated with major TT pre-operatively (OR 2.39, 95% CI 1.83-3.11), pre-operative entropic lashes compared to misdirected/metaplastic lashes (OR 1.99, 95% CI 1.23-3.20), age over 40 years (OR 1.59, 95% CI 1.14-2.20) and specific surgeons (surgeon recurrence risk range: 18%-53%). Granuloma occurred in 69 (5.7%) and notching in 156 (13.0%). CONCLUSIONS/SIGNIFICANCE: Risk of recurrence is high despite high volume, highly trained surgeons. However, the vast majority are minor recurrences, which may not have significant corneal or visual consequences. Inter-surgeon variation in recurrence is concerning; surgical technique, training and immediate post-operative lid position require further investigation

Transferrin changes in haemodialysed patients

Transferrin (Tf) is a glycoprotein responsible for iron transport in the human body. Physiologically in reaction with Concanavalin A, Tf occurs in four distinct variants Tf1, Tf2, Tf3 (apo-Tf) and Tf4. It was reported recently that Tf is changing, particularly during acute phase response, taking place among others in end-stage renal disease. In this study, we wanted to find the answer to three main questions: firstly, how Tf is changing in patients treated with maintenance haemodialysis (mHD), secondly, whether there are any Tf changes in the course of mHD treatment, and thirdly, what factors can affect Tf microheterogeneity in these patients. Studies were performed on 80 haemodialysed patients and 21 healthy volunteers. The Tf concentration was determined by the rocket immunoelectrophoresis, and its microheterogeneity was assessed by the ConA crossed immunoaffinity electrophoresis. During the annual observation of the distribution of the Tf variants, we have found both changes of the percentage contents of all Tf variants in the whole Tf concentration and a significant decrease in Tf2, Tf3 and Tf4 serum concentrations. Moreover, we found that decrease in the renal function, duration of mHD, and inflammation may contribute to these above-mentioned changes, which are probably the factors that should be taken into account when explaining the mechanisms of persistence of anaemia in haemodialysed patients