Compact and fast-response optical switch based on complex refractive index engineering.

The optical switch is a crucial device in integrated photonic circuits. Among the various types of optical switches available, the on-off Mach-Zehnder interferometer is one of the most widely used structures. However, compared with other structures, such as a microring, the large footprint of a Mach-Zehnder interferometer significantly restricts the integration density. In this paper, we propose a compact Mach-Zehnder interferometer based on complex refractive index engineering. By manipulating the complex index of the material in the structure, the lateral size of the device can be compressed down to only 3.25 µm. Moreover, the reducing of the space between heaters and waveguides leads to a fast response of only 1.9 µs. Our work offers a new, to the best of our knowledge, approach of a compact integrated optical switch, and opens a new avenue for application of absorbing materials.

Complex-valued matrix-vector multiplication system for a large-scale optical FFT.

Recent advancements in optical convolutional neural networks (CNNs) and radar signal processing systems have brought an increasing need for the adoption of optical fast Fourier transform (OFFT). Presently, the fast Fourier transform (FFT) is executed using electronic means within prevailing architectures. However, this electronic approach faces limitations in terms of both speed and power consumption. Concurrently, existing OFFT systems struggle to balance the demands of large-scale processing and high precision simultaneously. In response, we introduce a novel, to the best of our knowledge, solution: a complex-valued matrix-vector system harnessed through wavelength selective switches (WSSs) for the realization of a 24-input optical FFT, achieving a high-accuracy level of 5.4 bits. This study capitalizes on the abundant wavelength resources available to present a feasible solution for an optical FFT system with a large N.

Comparison of permeabilities of eight different types of cytotoxic drugs to five gloves with different materials by LC-MS/MS methods to reduce occupational exposure of medical personnel.

PURPOSE: Occupational exposure is a long-standing public health concern, which has drawn more and more attention in recent years to the problem of how to carry out occupational protection effectively. Gloves are regarded as the most critical protective equipment for cytotoxic medications. However, there is still little research conducted on the protective performance of gloves made of different materials and the optimal glove combination for cytotoxic agents. METHODS: In this research, a specific instrument intended for glove permeation experiment was designed, with various methods of liquid chromatography-tandem mass spectrometry (LC-MS/MS) developed and validated. By using the specific instrument and LC-MS/MS methods, a study was conducted on the permeation ability of eight selected cytotoxic drugs (fluorouracil, epirubicin (EPI), docetaxel (DCT), methotrexate (MTX), cyclophosphamide (CTX), etoposide (ETP), vincristine sulfate (VCR), and cisplatin derivatives Pt-(DDTC)3) into five kinds of gloves (rubber (RB), nitrile (NT), chlorinated polyethylene (CPE), low-density polyethylene, and polyvinylchloride (PVC) resin) given different contact times. Then, the experimental data were analyzed through a generalized estimation equation and Pearson correlation analysis. RESULTS: The results show that within a short period of time (less than five minutes), ETP, CTX, fluorouracil, DCT, and cisplatin passed through five types of gloves but the level of MTX, VCR, and EPI permeation was minimal, despite the duration of contact between the three drugs and the gloves reaching as long as three hours. Furthermore, the permeation of DCT and ETP was found to be positively correlated with time. CONCLUSIONS: Chlorinated polyethylene and PVC resin perform well in protecting against most cytotoxic drugs and are recommendable for clinical practice. Due to the poor protective ability, RB gloves are not recommended for this purpose. Based on the performance of various gloves in offering protection, the protection grade of two gloves can be deduced. Chlorinated polyethylene + PVC resin, CPE + NT glove combination shows good protective performance against most target drugs and can be recommended for clinical practice.

Comparative Analysis of Volatile Compounds from Four Radish Microgreen Cultivars Based on Ultrasonic Cell Disruption and HS-SPME/GC-MS.

The ultrasonic cell disruption method was used to efficiently extract isothiocyanates and other volatile compounds from radish microgreens. A total of 51 volatiles were identified and quantified by headspace solid-phase micro-extraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS) in four radish microgreen cultivars, mainly including alcohols, aldehydes, isothiocyanates, sulfides, ketones, esters, terpenes, and hydrocarbons. The correlation between cultivars and volatile compounds was determined by chemometrics analysis, including principal component analysis (PCA) and hierarchical clustering heat maps. The aroma profiles were distinguished based on the odor activity value (OAV), odor contribution rate (OCR), and radar fingerprint chart (RFC) of volatile compounds. This study not only revealed the different flavor characteristics in four cultivars but also established a theoretical basis for the genetic improvement of radish microgreen flavors.

Charge Transfer in Patterned Bilayer Film of Ag/ZnS Composite by Magnetron Control Sputtering.

Ordered heterojunction nanocap arrays composed of the bilayer film Ag/ZnS were prepared onto ordered two-dimensional polystyrene bead arrays by magnetron control sputtering, and the surface morphologies were tuned by changing the ZnS thickness. When the ZnS thickness varied from 10 to 30 nm with a Ag thickness of 5 nm, the roughness of the bilayer film Ag/ZnS increased obviously. The UV-VIS spectra showed the shifted LSPR peaks with ZnS thickness, which was attributed to the changes of the electron density as confirmed by Hall effect analysis. SERS observations confirmed the charge transfer process for the varied electromagnetic couplings when the ZnS thickness changed.

Suppression and revival of single-cavity lasing induced by polarization-dependent loss.

For most photonics devices and systems, loss is desperately averted, since it will increase the power consumption and degrade the performance. However, in some non-Hermitian systems, loss can induce a modal gain when the parity-time symmetry is broken, which offers a new way to manipulate the lasing of active cavities. Here we experimentally observe the counterintuitive phenomenon in a single laser cavity assisted by the polarization-dependent loss. A parity-time symmetric system is constituted by the two orthogonally polarized photonic loops in a single laser cavity, which can guarantee the consistency of two coupling loops. The measured output power of the cavity depends on the cross-polarization loss, which reveals virtually opposite relationships before and after the critical point. It provides a novel, to the best of our knowledge, understanding of polarization loss and shows great potential for lasing manipulation in a single cavity with polarization control.

NPD1 inhibits excessive autophagy by targeting RNF146 and wnt/ß-catenin pathway in cerebral ischemia-reperfusion injury.

Objective: Cerebral ischemia-reperfusion (I/R) injury is a common pathological feature in ischemic stroke. Autophagy plays a key role in I/R-induced neuronal death. Neuroprotectin D1 (NPD1) is a docosahexaenoic acid derivative with neuroprotective and anti-inflammatory properties. The purpose of this study was to investigate the mediatory role of NPD1 on I/R-induced injury and to elucidate the underlying mechanisms involved in this process.Methods: An I/R injury model was established in PC12 cells induced by oxygen and glucose deprivation/reoxygenation (OGD/R). NPD1 at increasing doses (5, 10, 20, 50, 100 nM) were added to cells one hour before OGD/R. To investigate the effect of ring finger protein 146 (RFP146) deficiency in I/R injury, PC12 cells were transiently transfected with small interfering RNF146 before further experiment.Results: Compared to the controls, OGD/R-challenged cells exhibited significantly decreased cell viability, induced oxidative stress, and excessive autophagic cell death following OGD/R. Pretreatment with NPD1 protected cells against ischemic injury as evidenced by enhanced cell survival, decreased oxidative stress markers, and a lower level of autophagy compared to drug-free group. OGD/R also increased the level of RFP146 and inhibited the expression of ß-catenin in PC12 cells. NPD1 treatment promoted the production of RNF146 and ß-catenin in cells following OGD/R experiment. Moreover, RNF146 deficiency significantly inhibited ß-catenin expression and reversed the protective effects of NPD1 in OGD/R-induced cells.Conclusion: NPD1 alleviated excessive autophagy via regulating RNF146 and Wnt/ß-catenin signaling, suggesting the potential therapeutic use of NPD1 for the protection against cerebral I/R injury.

Interaction between Translocation-associated membrane protein 1 and σC protein of novel duck reovirus controls virus infectivity.

Novel duck reovirus (NDRV), the prototype strain of the species Avian orthoreovirus (ARV), is associated with high mortality in Pekin ducklings. σC is an outer capsid protein encoded by the S1 genome segment of NDRV which mediates attachment to host cells. Our previous studies using immunoprecipitation and mass spectrometry found that σC coprecipitated with some host proteins including Translocation-associated membrane protein 1 (TRAM1). However, the interaction between σC and TRAM1 has not been further confirmed experimentally. In this study, we utilized coimmunoprecipitation assays, glutathione S-transferase pull-down, and confocal microscopy to confirm the interaction between σC and TRAM1. In addition, knockdown of TRAM1 using siRNA and overexpression of TRAM1 gene were conducted to explore its effect on virus replication. The result showed that TRAM1 silencing benefits while overexpression inhibits viral replication. This study confirms the important role TRAM1 during NDRV infection which can help develop new approaches for NDRV disease prevention and control.

Three-dimensional turbo-spin-echo amide proton transfer-weighted mri for cervical cancer: A preliminary study.

BACKGROUND: Amide proton transfer-weighted (APTw) imaging has shown great potential in the diagnosis of cancer, but has yet not been well studied in cervical cancer. PURPOSE: To evaluate the image quality and clinical feasibility of APTw MRI for cervical cancer. STUDY TYPE: Prospective. POPULATION: In all, 75 patients with cervical lesions and 49 healthy volunteers. FIELD STRENGTH/SEQUENCE: 3.0 T, 3D turbo spin echo (TSE) APTw sequence. ASSESSMENT: Three radiologists, blinded to the clinical data, independently evaluated APTw image quality with a 5-point Likert scale on 64 patients with pathologically confirmed cervical cancer. APT values, calculated based on asymmetry of acquired Z-spectrum with respect to water frequency, using 3D turbo spin echo volume acquisition with B0 correction, were independently measured by two radiologists, twice for each observer, on 52 cervical cancer lesions and 49 normal cervical stroma with a mean region of interest area of 638.6 mm2 and 557.5 mm2 , respectively. STATISTICAL TESTS: Interobserver agreement was evaluated by Kendall's W test. Intra- and interobserver interclass correlation coefficients (ICC) were computed. Student's t-test was used to compare the differences of APT values between cervical cancer and normal cervix; receiver operating characteristic analysis was performed. RESULTS: Most cases revealed good APTw image quality with excellent agreement (Kendall's W = 0.850, P < 0.001). APT values of cervical cancer and normal cervical stroma were 2.745 ± 0.065 and 1.853 ± 0.059, respectively, with a significant difference (P < 0.0001). Intraobserver ICCs were 0.963 and 0.960 for two readers. Interobserver ICC was 0.993. Area under the curve (AUC) for differentiating cervical cancer from normal cervical stroma was 0.927. The feasible threshold value for AUC was determined as 2.221 with sensitivity of 84.62% and specificity of 83.66%. DATA CONCLUSION: 3D TSE APTw MRI is feasible in cervical cancer. Cervical cancer showed significantly higher APT values than normal cervix. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1318-1325.

Comparative evaluation of five protocols for protein extraction from stony corals (Scleractinia) for proteomics.

Corals especially the reef-building species are very important to marine ecosystems. Proteomics has been used for researches on coral diseases, bleaching and responses to the environment change. A robust and versatile protein extraction protocol is required for coral proteomics. However, a comparative evaluation of different protein extraction protocols is still not available for proteomic analysis of stony corals. In the present study, five protocols were compared for protein extraction from stony corals. The five protocols were TRIzol, phenol-based extraction (PBE), trichloroacetic acid (TCA)-acetone, glass bead-assisted extraction (GBAE) and a commercially available kit. PBE, TRIzol and the commercial kit were more robust for extracting proteins from stony corals. The protein extraction efficiency and repeatability, two dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS) were employed to evaluate the protocols. The results indicated that PBE protocol had the better protein extraction efficiency than the others. Protein extraction coverage varied among the procedures. Each protocol favored for certain proteins. Therefore, it is very important for coral proteomic analysis to select a suitable protein protocol upon the experimental design. In general, PBE protocol can be the first choice for extracting proteins from stony corals.

Mode measurement of few-mode fibers by mode-frequency mapping.

Since few-mode fibers (FMFs) have great potential as the new transmission media for optical communications, the ability to distinguish different fiber modes is essential. Most of the traditional schemes do not yield phase information, or are limited by beam size and mechanical requirements. Here, a method is presented to analyze the mode distribution of FMFs. The fiber modes are mapped to different frequencies by using dynamic spatial phase masks. The complex amplitudes at these frequencies indicate the amplitudes and phases of the fiber modes. The method can extract not only the amplitude distribution, but also the phase distribution of the fiber modes, and no other assisted light is needed.

An integrated metabolomic and proteomic study of toxic effects of Benzo[a]pyrene on gills of the pearl oyster Pinctada martensii.

Benzo[a]pyrene (BaP) is one of the most important polycyclic aromatic hydrocarbons (PAHs), which are widely present in the marine environment. Because of its teratogenic, mutagenic, and carcinogenic effects on various organisms, the toxicity of BaP is of great concern. In this study, we focused on the toxic effects of BaP (1 µg/L and 10 µg/L) on gills of the pearl oyster Pinctada martensii using combined metabolomic and proteomic approaches. At the metabolome level, the high concentration of BaP mainly caused abnormal energy metabolism, osmotic regulation and immune response marked by significantly altered metabolites in gills. At the proteome level, both concentrations of BaP mainly induced signal transduction, transcription regulation, cell growth, stress response, and energy metabolism. Overall, the research demonstrated that the combination of proteomic and metabolomic approaches could provide a significant way to elucidate toxic effects of BaP on P. martensii.

Occurrence and distribution of Polycyclic aromatic hydrocarbons (PAHs) in seawater, sediments and corals from Hainan Island, China.

The levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated in corals, ambient seawater and sediments of Hainan Island, China, using gas chromatography - mass spectrometry (GC-MS). The total PAHs (∑PAHs) concentrations ranged from 273.79 to 407.82ng/L in seawater. Besides, the concentrations of ∑PAHs in corals 333.88-727.03ng/g dw) were markedly (P < 0.05) higher than ambient sediments 67.29-196.99ng/g dw), demonstrating the bioaccumulation ability of PAHs by corals. The highest concentration of ∑PAHs was detected at site S2 in Pavona decussate, which also bore the highest ∑PAHs levels in both seawater and sediments. The massive corals were more enriched with PAHs than the branching corals. Although 2 and 3-ring PAHs were predominant and accounted for 69.27-80.46% of the ∑PAHs in corals and ambient environment, the levels of high molecular weight (HMW) PAHs (4-6 ring) in corals also demonstrated their potential dangers for corals and organisms around coral reefs. Biota-sediment accumulation factor (BSAF) refers to an index of the pollutant absorbed by aquatic organisms from the surrounding sediments. The poor correlation between log BSAF and log Kow (hydrophobicity) indicated that PAHs in corals maybe not bioaccumulate from the ambient sediments but through pathways like absorbing from seawater, symbiosis, and feeding. Based on our data, long-term ecological monitoring in typical coral reef ecosystems combined with ecotoxicological tests of PAHs on corals is necessary to determine the impacts of PAHs on coral reefs.

Ambipolar Barristors for Reconfigurable Logic Circuits.

Vertical heterostructures based on graphene have emerged as a unique architecture for novel electronic devices with unusual characteristics. Here we report a new design of vertical ambipolar barristors based on metal-graphene-silicon-graphene sandwich structure, using the bottom graphene as a gate-tunable "active contact", the top graphene as an adaptable Ohmic contact, and the low doping thin silicon layer as the switchable channel. Importantly, with finite density of states and weak screening effect of graphene, we demonstrate, for the first time, that both the carrier concentration and majority carrier type in the sandwiched silicon can be readily modulated by gate potential penetrating through graphene. It can thus enable a new type of ambipolar barristors with an ON-OFF ratio exceeding 103. Significantly, these ambipolar barristors can be flexibly configured into either p-type or n-type transistors and used to create integrated circuits with reconfigurable logic functions. This unconventional device structure and ambipolar reconfigurable characteristics can open up exciting opportunities in future electronics based on graphene or two-dimensional van der Waals heterostructures.

Tomographic polarization analyzer by polarization-mode-frequency mapping.

A tomographic polarization analyzer is presented by polarization-mode-frequency mapping. Two orthogonal circularly polarized components of the unknown polarization state of light are converted to two orbital angular momentum (OAM) modes by a q-plate, and then the OAM modes are mapped to two frequencies by using time-varying spatial modulation. The polarization state of light can be retrieved by tomographic reconstruction of the temporal intensity signal collected by a photodetector. The time-varying spatial modulation can be achieved by either a programmable spatial device or a spinning object. Our method can directly measure the Jones matrix of light with high accuracy due to the high-volume time sampling.

Effects of pyrene exposure on immune response and oxidative stress in the pearl oyster, Pinctada martensii.

Pyrene is a polycyclic aromatic hydrocarbon (PAH) commonly observed in aquatic ecosystems, which originates primarily from the incomplete combustion of fossil fuels and the use of petroleum compounds. Pyrene can cause the immune disturbance and oxidative stress, result in immunotoxicity, DNA damage, reduce reproduction significantly, and induce behavioral changes. Marine bivalves are commonly used as bioindicators for marine pollution, and hemolymph is a metabolite transfer medium for PAH pollutant. However, the vital immune indicator responses of pearl oyster Pinctada martensii hemolymph exposed to pyrene is still unclear. Thus, the immunotoxic responses of pyrene on the hemolymph of the Pinctada martensii were investigated in this study. After exposure to pyrene for 7 days, the total number of hemocytes (THC), cell membrane stability (CMS), phagocytic activity (PA) and total glutathione (GSHT) all decreased significantly. Pyrene also caused a significant increase in lipid peroxidation (LPO). Median effective concentrations (EC50) of pyrene on THC (4.5 µg L-1) and LPO (5.2 µg L-1) were lower than those for CMS (13.8 µg L-1), PA (12.1 µg L-1) and GSHT (7.2 µg L-1), which indicates that THC and LPO were more sensitive. Additionally, a clear dose-effect relationship indicated that pyrene stimulated a marked immune response, as well as oxidative stress in P. martensii, which demonstrates the subtle effects of pyrene exposure on marine invertebrates and the potential associated risk.

Seasonal modeling of hand, foot, and mouth disease as a function of meteorological variations in Chongqing, China.

Hand, foot, and mouth disease (HFMD) is an enterovirus-induced infectious disease, mainly affecting children under 5 years old. Outbreaks of HFMD in recent years indicate the disease interacts with both the weather and season. This study aimed to investigate the seasonal association between HFMD and weather variation in Chongqing, China. Generalized additive models and distributed lag non-linear models based on a maximum lag of 14 days, with negative binomial distribution assumed to account for overdispersion, were constructed to model the association between reporting HFMD cases from 2009 to 2014 and daily mean temperature, relative humidity, total rainfall and sun duration, adjusting for trend, season, and day of the week. The year-round temperature and relative humidity, rainfall in summer, and sun duration in winter were all significantly associated with HFMD. An inverted-U relationship was found between mean temperature and HFMD above 19 °C in summer, with a maximum morbidity at 27 °C, while the risk increased linearly with the temperature in winter. A hockey-stick association was found for relative humidity in summer with increasing risks over 60%. Heavy rainfall, relative to no rain, was found to be associated with reduced HFMD risk in summer and 2 h of sunshine could decrease the risk by 21% in winter. The present study showed meteorological variables were differentially associated with HFMD incidence in two seasons. Short-term weather variation surveillance and forecasting could be employed as an early indicator for potential HFMD outbreaks.

Theoretical analysis and experimental verification on optical rotational Doppler effect.

We present a theoretical model to sufficiently investigate the optical rotational Doppler effect based on modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the difference of mode index between input and output orbital angular momentum (OAM) light, and linear to the rotating speed of spinning object as well. An experiment is carried out to verify the theoretical model. We explicitly suggest that the spatial spiral phase distribution of spinning object determines the frequency content. The theoretical model makes us better understand the physical processes of rotational Doppler effect, and thus has many related application fields, such as detection of rotating bodies, imaging of surface and measurement of OAM light.

Large area growth and electrical properties of p-type WSe2 atomic layers.

Transition metal dichacogenides represent a unique class of two-dimensional layered materials that can be exfoliated into single or few atomic layers. Tungsten diselenide (WSe(2)) is one typical example with p-type semiconductor characteristics. Bulk WSe(2) has an indirect band gap (∼ 1.2 eV), which transits into a direct band gap (∼ 1.65 eV) in monolayers. Monolayer WSe(2), therefore, is of considerable interest as a new electronic material for functional electronics and optoelectronics. However, the controllable synthesis of large-area WSe(2) atomic layers remains a challenge. The studies on WSe(2) are largely limited by relatively small lateral size of exfoliated flakes and poor yield, which has significantly restricted the large-scale applications of the WSe(2) atomic layers. Here, we report a systematic study of chemical vapor deposition approach for large area growth of atomically thin WSe(2) film with the lateral dimensions up to ∼ 1 cm(2). Microphotoluminescence mapping indicates distinct layer dependent efficiency. The monolayer area exhibits much stronger light emission than bilayer or multilayers, consistent with the expected transition to direct band gap in the monolayer limit. The transmission electron microscopy studies demonstrate excellent crystalline quality of the atomically thin WSe(2). Electrical transport studies further show that the p-type WSe(2) field-effect transistors exhibit excellent electronic characteristics with effective hole carrier mobility up to 100 cm(2) V(-1) s(-1) for monolayer and up to 350 cm(2) V(-1) s(-1) for few-layer materials at room temperature, comparable or well above that of previously reported mobility values for the synthetic WSe(2) and comparable to the best exfoliated materials.

Metabolite profiles of Populus in response to pathogen stress.

Populus canker is a widespread disease that seriously affects the growth and productivity of trees, and may even cause tree death. To assess the metabolic changes in Populus in response to pathogen stress, Populus stems infected or not with Dothiorella gregaria were analyzed by GC-MS. A total of 4, 051 features were detected and 44 metabolites were identified to be changed significantly in Populus upon infection. The identified responsive metabolites include saccharides, alcohols, organic acids, and amino acids and some secondary metabolites and most of the metabolites were detected at increased levels. Responsive metabolites were investigated about their metabolism pathway and the corresponding metabolic networks were further constructed. To our knowledge, this is the first study to identify the metabolite profiles of Populus in response to pathogen stress. The results extend our understanding of the mechanisms involved in the defense of Populus against pathogens and provide a basis for further research on plant defenses.