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The optical, plasmonic, and imaging performance of an infra-red polarized system exceeds that of a conventional infra-red detector due to its high resolution and precision.

An InGaAsP (1.04 eV)/InGaAs (0.54 eV) dual-junction solar cell, monolithically grown in an inverted configuration on an InP substrate, has been demonstrated.

Ca2+influx into the trans-Golgi Network (TGN) promotes secretory cargo sorting by the Ca2+-ATPase SPCA1 and the luminal Ca2+binding protein Cab45. Cab45 oligomerizes upon a local Ca2+influx, and Cab45 oligomers sequester and separate soluble secretory cargo from the bulk flow of proteins in the TGN. However, how this Ca2+flux into the lumen of the TGN is achieved remains elusive, as the cytosol has a very low steady-state Ca2+concentration. The TGN forms membrane contact sites (MCS) with the Endoplasmic Reticulum (ER), whereby the close apposition of the two organelles allows the protein-mediated exchange of molecular species such as lipids. Here we show that the TGN export of Cab45 clients requires the integrity of ER-TGN MCS and IP3R-dependent Ca2+fluxes in the MCS, suggesting Ca2+transfer between these organelles. Using an MCS-targeted Ca2+FRET sensor module, we measure the Ca2+flow in these sites in real-time. These data show for the first time that ER-TGN MCS facilitates Ca2+transfer required for SPCA1-dependent cargo sorting and export from the TGN, thus solving a fundamental question in cell biology.SummaryThe current study demonstrates that the trafficking of COMP and LyzC relies on Ca2+flux between the endoplasmic reticulum (ER) and trans-Golgi Network (TGN). This process requires the activity of IP3 receptors, present in ER membranes, and depends on the integrity of the membrane contact site between these two organelles.

With one-third of all newly synthesized proteins entering the secretory pathway, correct protein sorting is essential for cellular homeostasis. In the last three decades, researchers have developed numerous biochemical, genetic, and cell biological approaches to study protein export and sorting from the trans-Golgi network (TGN). However, accurately quantifying protein transport from one compartment to the next in the secretory pathway has been challenging. The Retention Using Selective Hooks (RUSH) system is a method that allows monitoring trafficking of a protein of interest in real time, similar to a pulse-chase experiment but without the need of radiolabeling. Accurate calculations, however, are necessary and currently lacking. Here, we combine the RUSH system with live cell imaging to quantify and calculate half lives. We exemplify our approach using a soluble secreted protein (LyzC). This system will benefit membrane trafficking researchers by adding numbers to protein export and comparing the export kinetics of different cargoes and variating conditions.

We present the design and fabrication results for wavelength tuning of InAs/GaSb type-II superlattice spectral response based on square coaxial aperture array at mid-wave infrared. This structure is designed as a wavelength adjustable filter with different parameters in the 2 – 6 μm. Its spectrum does not depend on the angle of the incident light and has a Gaussian shape. There was a slight difference in the designed parameters due to imperfection fabrication, but the trend of the spectrum according to the difference was confirmed and analyzed by simulation. The spectral responsivity of the device was measured, and wavelength tuning was observed.

The structural and optical properties of InAsxP1-x metamorphic buffers grown by metal–organic chemical vapor deposition on InP (100) substrates have been investigated. High-resolution X-ray reciprocal space mapping around the (115) InP lattice point reveals that the strain relaxations of the InAsxP1-x with x = 0.5, 0.55, and 0.7 are 98%, 92%, and 96%, while the lateral correlation lengths are 17, 62, and 28 nm, respectively. The optical bandgap energy of the InAsP derived from photoreflectance (PR) measurements decreases from 0.819 to 0.621 eV at 300 K when increasing As composition from x = 0.5 to 0.7. The bowing parameter for the optical bandgap of the InAsP is increased with increasing As composition, which is attributable to the increased spontaneous CuPt-type ordering in InAsP. It is found from the excitation power-dependent PR measurement that the InAsxP1-x layers have different degrees of the bandgap redshift due to the reduced thermal conductivity caused by crystal imperfections generated during the strain relaxation process.

We grew and characterized Zn- and Si-doped In0.48Ga0.52P grown on (0 0 1) GaAs substrates misoriented by θS = 0°, 2°, 6°, and 10° toward (1 1 1)A using metal-organic chemical vapor deposition. The dopant incorporation efficiency is improved with higher θS because of a larger surface free energy. The lattice constant of InGaP is increased with higher doping concentration, whereas it is decreased with higher θS as a result of reduced CuPt-type ordering in InGaP. This reduced ordering with θS from 0° to 10° is supported by a bandgap increase of ~60 meV. The open-circuit voltage of InGaP solar cell with θS = 10° is more than 100 meV higher than that with θS = 2° due to the increased bandgap and the decrease of the ordering-related defects. Besides, a larger CuPt-type ordering results in a greater reduction of the thermal activation energy of InGaP solar cell.

Drosophila suzukii is a serious agricultural pest. The evolved morphology of the female D. suzukii assists in penetrating the surface of fresh fruit and spawns eggs with its unique ovipositor. Conversely, Drosophila melanogaster, a taxonomically close species with D. suzukii, largely inhabits decaying and fermenting fruits and is consistently exposed to extensive environmental chemicals, such as 2-phenylethanol, ethanol, and acetic acid, produced by microorganisms. Considering the distinct habitats of the two flies, D. suzukii is thought to be more susceptible to environmental chemicals than D. melanogaster. We investigated the significantly higher survival rate of D. melanogaster following exposure to 2-phenylethanol, ethanol, and acetic acid. A comparison of the expression of antimicrobial peptides (AMPs) between the two flies treated with chemicals established that AMPs were generally more abundantly induced in D. melanogaster than in D. suzukii, particularly in the gut and fat body. Among the AMPs, the induction of genes (Diptericin A, Diptericin B, and Metchnikowin), which are regulated by the immune deficiency (IMD) pathway, was significantly higher than that of Drosomycin, which belongs to the Toll pathway in chemical-treated D. melanogaster. A transgenic RNAi fly (D. melanogaster) with silenced expression of AMPs and Relish, a transcription factor of the IMD pathway, exhibited significantly reduced survival rates than the control fly. Our results suggest that AMPs regulated by the IMD pathway play an important role in the chemical tolerance of D. melanogaster, and these flies are adapted to their habitats by physiological response.

Sphingomyelin is a dominant sphingolipid in mammalian cells. Its production in the trans-Golgi traps cholesterol synthesized in the ER to promote formation of a sphingomyelin/sterol gradient along the secretory pathway. This gradient marks a fundamental transition in physical membrane properties that help specify organelle identify and function. We previously identified mutations in sphingomyelin synthase SMS2 that cause osteoporosis and skeletal dysplasia. Here we show that SMS2 variants linked to the most severe bone phenotypes retain full enzymatic activity but fail to leave the ER owing to a defective autonomous ER export signal. Cells harboring pathogenic SMS2 variants accumulate sphingomyelin in the ER and display a disrupted transbilayer sphingomyelin asymmetry. These aberrant sphingomyelin distributions also occur in patient-derived fibroblasts and are accompanied by imbalances in cholesterol organization, glycerophospholipid profiles and lipid order in the secretory pathway. We postulate that pathogenic SMS2 variants undermine the capacity of osteogenic cells to uphold nonrandom lipid distributions that are critical for their bone forming activity.

The incident light intensity (Iex) effects on a GaAs single junction solar cell (SC) was investigated using bright electroreflectance spectroscopy (BER) and current-voltage (J-V) measurements at room temperature. The p-n junction electric field (Fpn) of the SC was evaluated by analyzing the Franz Keyldesh oscillation (FKO) in the BER spectra. The Iex effect on Fpn was investigated at various incident light intensities from 0.03 to 25 suns. The Fpn decreased gradually with increasing Iex due to the photovoltaic effect. For the forward bias voltage, some part of the electrons and holes drifted to the p and n sides, respectively, and produced the induced electric field in the same direction of the Fpn. Therefore, the Fpn increased up to 2.5 suns. At more than 2.5 suns, most of the electrons and holes moved to the n and p sides and decreased the Fpn due to the photovoltaic effect. In addition, the Fpn was examined under light illumination as a function of different DC bias voltages (−0.2–0.4 V). The Fpn decreased with increasing bias voltage due to the decrease in potential barrier. The Fpn increased with increasing bias voltage due to the decrease in the photogenerated carrier-induced electric field for high Iex.

Monolithic InGaAs/InAsPSb MQW LEDs have been demonstrated. The eSWIR light sources are fully strain-relaxed on the InAs x P1- x metamorphic virtual substrate. The novel InAsPSb barrier can successfully enhance the confinement of the electrons in QWs.

Lysosomes are vital organelles vulnerable to injuries from diverse materials. Failure to repair or sequester damaged lysosomes poses a threat to cell viability. Here we report that cells exploit a sphingomyelin-based lysosomal repair pathway that operates independently of ESCRT to reverse potentially lethal membrane damage. Various conditions perturbing organelle integrity trigger a rapid calcium-activated scrambling and cytosolic exposure of sphingomyelin. Subsequent metabolic conversion of sphingomyelin by neutral sphingomyelinases on the cytosolic surface of injured lysosomes promotes their repair, also when ESCRT function is compromised. Conversely, blocking turnover of cytosolic sphingomyelin renders cells more sensitive to lysosome-damaging drugs. Our data indicate that calcium-activated scramblases, sphingomyelin, and neutral sphingomyelinases are core components of a previously unrecognized membrane restoration pathway by which cells preserve the functional integrity of lysosomes.

Recently, pesticides have been suggested to be one of the factors responsible for the large-scale decline in honey bee populations, including colony collapse disorder. The identification of the genes that respond to pesticide exposure based on their expression is essential for understanding the xenobiotic detoxification metabolism in honey bees. For the accurate determination of target gene expression by quantitative real-time PCR, the expression stability of reference genes should be validated in honey bees exposed to various pesticides. Therefore, in this study, to select the optimal reference genes, we analyzed the amplification efficiencies of five candidate reference genes (RPS5, RPS18, GAPDH, ARF1, and RAD1a) and their expression stability values using four programs (geNorm, NormFinder, BestKeeper, and RefFinder) across samples of five body parts (head, thorax, gut, fat body, and carcass) from honey bees exposed to seven pesticides (acetamiprid, imidacloprid, flupyradifurone, fenitrothion, carbaryl, amitraz, and bifenthrin). Among these five candidate genes, a combination of RAD1a and RPS18 was suggested for target gene normalization. Subsequently, expression levels of six genes (AChE1, CYP9Q1, CYP9Q2, CYP9Q3, CAT, and SOD1) were normalized with a combination of RAD1a and RPS18 in the different body parts from honey bees exposed to pesticides. Among the six genes in the five body parts, the expression of SOD1 in the head, fat body, and carcass was significantly induced by six pesticides. In addition, among seven pesticides, flupyradifurone statistically induced expression levels of five genes in the fat body.

Lysosomes are vital organelles vulnerable to injuries from diverse materials. Failure to repair or sequester damaged lysosomes poses a threat to cell viability. Here we report that cells exploit a sphingomyelin-based lysosomal repair pathway that operates independently of ESCRT to reverse potentially lethal membrane damage. Various conditions perturbing organelle integrity trigger a rapid calcium-activated scrambling and cytosolic exposure of sphingomyelin. Subsequent metabolic conversion of sphingomyelin by neutral sphingomyelinases on the cytosolic surface of injured lysosomes promotes their repair, also when ESCRT function is compromised. Conversely, blocking turnover of cytosolic sphingomyelin renders cells more sensitive to lysosome-damaging drugs. Our data indicate that calcium-activated scramblases, sphingomyelin, and neutral sphingomyelinases are core components of a previously unrecognized membrane restoration pathway by which cells preserve the functional integrity of lysosomes.

The algorithmic spectrometry as an alternative to traditional approaches has the potential to become the next generation of infrared (IR) spectral sensing technology, which is free of physical optical filters, and only a very small number of data are required from the IR detector. A key requirement is that the detector spectral responses must be engineered to create an optimal basis that efficiently synthesizes spectral information. Light manipulation through metal perforated with a two-dimensional square array of subwavelength holes provides remarkable opportunities to harness the detector response in a way that is incorporated into the detector. Instead of previous experimental efforts mainly focusing on the change over the resonance wavelength by tuning the geometrical parameters of the plasmonic layer, we experimentally and numerically demonstrate the capability for the control over the shape of bias-tunable response spectra using a fixed plasmonic structure as well as the detector sensitivity improvement, which is enabled by the anisotropic dielectric constants of the quantum dots-in-a-well (DWELL) absorber and the presence of electric field along the growth direction. Our work will pave the way for the development of an intelligent IR detector, which is capable of direct viewing of spectral information without utilizing any intervening the spectral filters.

Infrared (IR) polarimetric imaging has attracted attention as a promising technology in many fields. Generally, superpixels consisting of linear polarizer elements at different angles plus IR imaging array are used to obtain the polarized target signature by using the detected polarization-sensitive intensities. However, the spatial arrangement of superpixels across the imaging array may lead to an incorrect polarimetric signature of a target, due to the range of angles from which the incident radiation can be collected by the detector. In this article, we demonstrate the effect of the incident angle on the polarization performance of an alternative structure where a dielectric layer is inserted between the nanoimprinted subwavelength grating layers. The well-designed spacer creates the Fabry–Perot cavity resonance, and thereby, the intensity of transverse-magnetic I-polarized light transmitted through two metal grating layers is increased as compared with a single-layer metal grating, whereas transverse-electric (TE)-transmitted light intensity is decreased. TM-transmittance and polarization extinction ratio (PER) of normally incident light of wavelength 4.5 μm are obtained with 0.49 and 132, respectively, as the performance of the stacked subwavelength gratings. The relative change of the PERs for nanoimprint-lithographically fabricated double-layer grating samples that are less than 6% at an angle of incidence up to 25°, as compared to the normal incidence. Our work can pave the way for practical and efficient polarization-sensitive elements, which are useful for many IR polarimetric imaging applications.

Background The most relevant time of PM10 exposure to affect airway hyperresponsiveness (AHR) and new development of asthma in school-aged children is unclear. The aims of this study were to investigate the most critical time of PM10 exposure to affect AHR and new diagnosis of asthma from AHR in school-aged children. Methods Elementary schoolchildren (n = 3570) have been enrolled in a nationwide prospective 4-year follow-up survey in Korea from 2005 to 2006. Individual annual PM10 exposure was estimated by using an ordinary kriging method from the prenatal period to 7 years of age. AHR at 7 years was defined by a methacholine PC20 ≤8 mg/mL. Results PM10 exposure during pregnancy and at 1 year of age showed significant effects on AHR (aOR: 1.694, 95% CI: 1.298-2.209; and aOR: 1.750, 95% CI: 1.343-2.282, respectively). PM10 exposure during pregnancy was associated with the risk of a new diagnosis of asthma (aOR: 2.056, 95% CI: 1.240-3.409), with the highest risk in children with AHR at age 7 (aOR: 6.080, 95% CI: 2.150-17.195). PM10 exposure in the second trimester was associated with the highest risk of a new diagnosis of asthma in children with AHR at age 7 (aOR: 4.136, 95% CI: 1.657-10.326). Conclusions Prenatal PM10 exposure in the second trimester is associated with an increased risk of a new diagnosis of asthma in school-aged children with AHR at 7 years. This study suggests that PM10 exposure during a specific trimester in utero may affect the onset of childhood asthma via AHR.