Dynamic Recruitment of the Feedforward and Recurrent Mechanism for Black-White Asymmetry in the Primary Visual Cortex.

Black and white information is asymmetrically distributed in natural scenes, evokes asymmetric neuronal responses, and causes asymmetric perceptions. Recognizing the universality and essentiality of black-white asymmetry in visual information processing, the neural substrates for black-white asymmetry remain unclear. To disentangle the role of the feedforward and recurrent mechanisms in the generation of cortical black-white asymmetry, we recorded the V1 laminar responses and LGN responses of anesthetized cats of both sexes. In a cortical column, we found that black-white asymmetry starts at the input layer and becomes more pronounced in the output layer. We also found distinct dynamics of black-white asymmetry between the output layer and the input layer. Specifically, black responses dominate in all layers after stimulus onset. After stimulus offset, black and white responses are balanced in the input layer, but black responses still dominate in the output layer. Compared with that in the input layer, the rebound response in the output layer is significantly suppressed. The relative suppression strength evoked by white stimuli is notably stronger and depends on the location within the ON-OFF cortical map. A model with delayed and polarity-selective cortical suppression explains black-white asymmetry in the output layer, within which prominent recurrent connections are identified by Granger causality analysis. In addition to black-white asymmetry in response strength, the interlaminar differences in spatial receptive field varied dynamically. Our findings suggest that the feedforward and recurrent mechanisms are dynamically recruited for the generation of black-white asymmetry in V1.SIGNIFICANCE STATEMENT Black-white asymmetry is universal and essential in visual information processing, yet the neural substrates for cortical black-white asymmetry remain unknown. Leveraging V1 laminar recordings, we provided the first laminar pattern of black-white asymmetry in cat V1 and found distinct dynamics of black-white asymmetry between the output layer and the input layer. Comparing black-white asymmetry across three visual hierarchies, the LGN, V1 input layer, and V1 output layer, we demonstrated that the feedforward and recurrent mechanisms are dynamically recruited for the generation of cortical black-white asymmetry. Our findings not only enhance our understanding of laminar processing within a cortical column but also elucidate how feedforward connections and recurrent connections interact to shape neuronal response properties.

Multiple gamma rhythms carry distinct spatial frequency information in primary visual cortex.

Gamma rhythms in many brain regions, including the primary visual cortex (V1), are thought to play a role in information processing. Here, we report a surprising finding of 3 narrowband gamma rhythms in V1 that processed distinct spatial frequency (SF) signals and had different neural origins. The low gamma (LG; 25 to 40 Hz) rhythm was generated at the V1 superficial layer and preferred a higher SF compared with spike activity, whereas both the medium gamma (MG; 40 to 65 Hz), generated at the cortical level, and the high gamma HG; (65 to 85 Hz), originated precortically, preferred lower SF information. Furthermore, compared with the rates of spike activity, the powers of the 3 gammas had better performance in discriminating the edge and surface of simple objects. These findings suggest that gamma rhythms reflect the neural dynamics of neural circuitries that process different SF information in the visual system, which may be crucial for multiplexing SF information and synchronizing different features of an object.

Doping strategies for inorganic lead-free halide perovskite solar cells: progress and challenges.

In recent years, remarkable advancements have been achieved in the field of halide perovskite solar cells (PSCs). However, the commercialization of PSCs has been impeded by challenges such as Pb leakage and the instability of hybrid organic-inorganic perovskites (HOIPs). Hence, the future lies in the development of environmentally friendly inorganic lead-free halide perovskites (LFHPs) based on elements like Sn, Ge, Bi, Sb, and Cu, which show great promise for photovoltaic applications. However, LFHP photovoltaic cells still face challenges such as low efficiency, poor film quality, and stability in comparison to HOIPs. These limitations significantly hinder their further development. To address these issues, element doping strategies, including cationic and anionic doping, as well as the use of additives, are frequently employed. These strategies aim to improve film quality, passivate defects, reduce the band gap, and enhance device performance and stability. In this paper, we aim to provide a comprehensive review of the recent research progress in doping strategies for LFHPs.

Aqueous production of secondary organic aerosol from fossil-fuel emissions in winter Beijing haze.

Secondary organic aerosol (SOA) produced by atmospheric oxidation of primary emitted precursors is a major contributor to fine particulate matter (PM2.5) air pollution worldwide. Observations during winter haze pollution episodes in urban China show that most of this SOA originates from fossil-fuel combustion but the chemical mechanisms involved are unclear. Here we report field observations in a Beijing winter haze event that reveal fast aqueous-phase conversion of fossil-fuel primary organic aerosol (POA) to SOA at high relative humidity. Analyses of aerosol mass spectra and elemental ratios indicate that ring-breaking oxidation of POA aromatic species, leading to functionalization as carbonyls and carboxylic acids, may serve as the dominant mechanism for this SOA formation. A POA origin for SOA could explain why SOA has been decreasing over the 2013-2018 period in response to POA emission controls even as emissions of volatile organic compounds (VOCs) have remained flat.

A simple strategy to obtain graphitic carbon nitride modified TiO2layer for efficient perovskite solar cells.

The power conversion efficiency (PCE) of perovskite solar cells (PSCs) can be improved through the concurrent strategies of enhancing charge transfer and passivating defects. Graphite carbon nitride (g-C3N4) has been demonstrated as a promising modifier for optimizing energy level alignment and reducing defect density in PSCs. However, its preparation process can be complicated. A simple one-step calcination approach was used in this study to prepare g-C3N4-modified TiO2via the incorporation of urea into the TiO2precursor. This modification simultaneously tunes the energy level alignment and passivates interface defects. The comprehensive research confirms that the addition of moderate amounts of g-C3N4to TiO2results in an ideal alignment of energy levels with perovskite, thereby enhancing the ability to separate and transfer charges. Additionally, the g-C3N4-modified perovskite films exhibit an increase in grain size and crystallinity, which reduces intrinsic defects density and extends charge recombination time. Therefore, the g-C3N4-modified PSC achieves a champion PCE of 20.00%, higher than that of the control PSC (17.15%). Our study provides a systematic comprehension of the interfacial engineering strategy and offers new insights into the development of high-performance PSCs.

Acute effects of ambient nitrogen dioxide exposure on serum biomarkers of nervous system damage in healthy older adults.

Ambient nitrogen dioxide (NO2)-induced adverse health effects have been studied, but documented evidence on neural systems is limited. This study aimed to determine the acute effect of NO2 exposure on nervous system damage biomarker levels in healthy older adults. Five rounds of follow-up among 34 healthy retired people were scheduled from December 2018 to April 2019 in Xinxiang, China. The real-time NO2 concentrations were measured using a fixed site monitor. Serum samples were acquired during each round to measure nervous system damage biomarker levels: brain-derived neurotrophic factor (BDNF), neurofilament light chain (NfL), neuron-specific enolase (NSE), protein gene product 9.5 (PGP9.5), and S100 calcium-binding protein B (S100B). A linear mixed-effect model was incorporated to analyze the association between short-term NO2 exposure and serum concentrations of the above-mentioned biomarkers. Stratification analysis based on sex, educational attainment, glutathione S-transferase theta 1 gene (GSTT1) polymorphism, and physical activity intensity was conducted to explore their potential modification effect. The NO2 concentration ranged from 34.7 to 59.0 µg/m3 during the study period. Acute exposure to ambient NO2 was significantly associated with elevated serum levels of NfL, PGP9.5, and BDNF. In response to a 10 µg/m3 increase in NO2 concentration, NfL and PGP9.5 levels increased by 76 % (95 % confidence interval [CI]: 12-140 %) and 54 % (95 % CI: 1-107 %) on the lag0 day, respectively, while BDNF levels increased by 49 % (95 % CI: 2-96 %) at lag4 day. The estimated effect of NO2 on NSE levels in GSTT1-sufficient participants was significantly higher than that in GSTT1-null participants. Intriguingly, the estimation of NO2 on PGP9.5 levels in females was significantly higher than that in males. Most two-pollutant models showed robust results, except for O3, which might have had confounding effects on NO2-induced BDNF stimulation. In summary, acute exposure to NO2 was associated with increased levels of serum nervous system damage biomarker levels including NFL, PGP9.5, and BDNF. The present study provided insights into NO2 exposure-induced adverse neural effects.

Organophosphate pesticide exposure and biomarkers of liver injury/liver function.

BACKGROUND AND AIMS: There is little epidemiological evidence linking the exposure of organophosphate pesticides (OPs) to liver function or liver injury in the general population. We used data from the National Health and Nutrition Examination Survey 1999-2012 to investigate the relationship of urinary OPs with biomarkers of liver function/liver injury. METHODS: The exposures were the concentrations of urinary OP metabolites (dimethyl phosphate [DMP], dimethyl thiophosphate [DMTP], diethyl phosphate [DEP] and diethyl thiophosphate [DETP]). The health outcomes were biomarkers of liver function/liver injury. The multivariable linear regression model, restricted cubic splines (RCSs) analysis and weighted quantile sum (WQS) regression were used to evaluate the relationship between individual or overall exposure of OPs and outcomes. RESULTS: Regressions of RCSs suggested linear and positive associations of OP metabolites with aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio (DMP and DEP) and fibrosis-4 (FIB-4) index (DMP, DEP and DMTP) (all p-non-linear values >.05). However, L-shaped relationships were found between OP metabolites (DMTP and DETP) and blood albumin and total protein (TP) concentrations (both p and non-linear values <.05). The positive associations of urinary DMP, DEP and DMTP with AST/ALT ratio, and with FIB-4 score were more pronounced among non-smokers than smokers, among alcohol drinkers than non-drinkers and among those with a body mass index (BMI) of ≥25 than participants with a BMI of <25. However, most of the interaction p values were more than .05, indicating no significant interactions between covariates and OPs on outcomes mainly including AST/ALT, FIB-4, ALB and TP levels. Finally, the WQS indices were positively associated with AST/ALT ratio (p = .014) and FIB-4 score (p = .002). CONCLUSIONS: Our study added novel evidence that exposures to OPs might be adversely associated with the biomarkers of liver function/liver injury. These findings indicated the potential toxic effect of OP exposures on the human liver.

NHC-Catalyzed Transformation Reactions of Imines: Electrophilic versus Nucleophilic Attack.

It is generally accepted that N-heterocyclic carbene (NHC)-catalyzed imine transformations are initiated by a nucleophilic attack (NA) by NHC. However, due to significant nucleophilicity of the iminyl nitrogen atom in imines, the electrophilic attack (EA) by electrophiles onto imine would also be a possible mechanism of these kinds of reactions. Therefore, we use the quantum mechanical approach to disclose that both the NA and EA modes could be switchable for a wide range of NHC-catalyzed transformations of imines.

Copper-Based Nanocatalysts with SiO2 and Carbon Dual-Layer Coatings and Metallic Ni/CuNi Decoration toward Highly Efficient Nitroaromatics Reduction.

Nanocomposites with novel architectures and multifunctional properties have attracted extensive attention among related researchers. Herein, we develop a magnetically responsive Ni/CuNi nanoparticle (NP) decoration of Cu-based composites that could serve as recoverable nanocatalysts for nitroaromatics reduction. The nanocatalysts consist of an inner copper core and abundant tiny satellite Ni/CuNi NPs, which are tightly combined as a stable whole part by a silica interlayer and a carbon outer layer. In addition to the high catalytic activity, the outer Ni/CuNi NPs exhibit a strong magnetic response toward the external magnetic field, thereby offering a convenient way to separate the composites from the reaction solution. Moreover, characterization results reveal that high annealing temperature (above 700 °C) favors the construction of yolk-shell nanostructures and the formation of outer bimetallic CuNi NPs. As a result, owing to the excellent catalytic performance of the Cu inner cores, the high coverage of outer Ni or CuNi NPs, and the unique sandwich-like structure, the resultant Cu@SiO2@C-Ni composites show the use of such magnetically responsive recoverable nanocatalysts for the 4-nitrophenol reduction. Hence, this research could provide new guidelines for designing and synthesizing novel and efficient copper-based composites for other fields, such as carbon dioxide reduction, energy storage, and batteries.

Associations of Short-Term Exposure to Fine Particulate Matter with Neural Damage Biomarkers: A Panel Study of Healthy Retired Adults.

Exposure to fine particulate matter (PM2.5) is associated with various adverse health effects, such as respiratory and cardiovascular diseases. This study aimed to evaluate the association of PM2.5 with neural damage biomarkers. A total of 34 healthy retirees were recruited from Xinxiang Medical University from December 2018 to April 2019. Concentrations of PM2.5 constituents including 24 metals and nonmetallic elements and 6 ions, and 5 biomarkers of neural damage including brain-derived neurotrophic factor (BDNF), neurofilament light chain (NfL), neuron-specific enolase (NSE), protein gene product 9.5 (PGP9.5), and S100 calcium-binding protein B (S100B) in serum were measured. A linear mixed-effect model was employed to estimate the association of PM2.5 and its constituents with neural damage biomarkers. Modification effects of glutathione S-transferase theta 1 gene (GSTT1) polymorphism, sex, education, and physical activity on PM2.5 exposure with neural damage were explored. PM2.5 and its key constituents were significantly associated with neural damage biomarkers. A 10 µg/m3 increase in PM2.5 concentration was associated with 2.09% (95% CI, 39.3-76.5%), 100% (95% CI, 1.73-198%), and 122% (95% CI, 20.7-222%) increments in BDNF, NfL, and PGP9.5, respectively. Several constituents such as Cu, Zn, Ni, Mn, Sn, V, Rb, Pb, Al, Be, Cs, Co, Th, U, Cl-, and F- were significantly associated with NfL. The estimated association of PM2.5 with NSE in GSTT1-sufficient volunteers was significantly higher than that in GSTT1-null volunteers. Therefore, short-term PM2.5 exposure was associated with neural damage, and GSTT1 expression levels modified the PM2.5-induced adverse neural effects.

Laminar Subnetworks of Response Suppression in Macaque Primary Visual Cortex.

Cortical inhibition plays an important role in information processing in the brain. However, the mechanisms by which inhibition and excitation are coordinated to generate functions in the six layers of the cortex remain unclear. Here, we measured laminar-specific responses to stimulus orientations in primary visual cortex (V1) of awake monkeys (male, Macaca mulatta). We distinguished inhibitory effects (suppression) from excitation, by taking advantage of the separability of excitation and inhibition in the orientation and time domains. We found two distinct types of suppression governing different layers. Fast suppression (FS) was strongest in input layers (4C and 6), and slow suppression (SS) was 3 times stronger in output layers (2/3 and 5). Interestingly, the two types of suppression were correlated with different functional properties measured with drifting gratings. FS was primarily correlated with orientation selectivity in input layers (r = -0.65, p < 10-9), whereas SS was primarily correlated with surround suppression in output layers (r = 0.61, p < 10-4). The earliest SS in layer 1 indicates the origin of cortical feedback for SS, in contrast to the feedforward/recurrent origin of FS. Our results reveal two V1 laminar subnetworks with different response suppression that may provide a general framework for laminar processing in other sensory cortices.SIGNIFICANCE STATEMENT This study sought to understand inhibitory effects (suppression) and their relationships with functional properties in the six different layers of the cortex. We found that the diversity of neural responses across layers in primary visual cortex (V1) could be fully explained by one excitatory and two suppressive components (fast and slow suppression). The distinct laminar distributions, origins, and functional roles of the two types of suppression provided a simplified representation of the differences between two V1 subnetworks (input network and output network). These results not only help to elucidate computational principles in macaque V1, but also provide a framework for general computation of cortical laminae in other sensory cortices.

Nuclear factor Y participates in alcoholic liver disease by activating SREBP1 expression in mice.

Chronic and excessive alcohol consumption leads to alcoholic liver disease (ALD). However, the molecular mechanisms in the regulation of ALD have not been fully deciphered. Liver lipid accumulation is an important research direction in ALD. In this study, the physiological role of nuclear factor Y (NF-Y) in ALD and the related mechanisms were investigated using murine hepatocytes and an ethanol-induced liver injury mouse model. In this study, ethanol promoted hepatic NF-Y expression in a mouse model and Hepa1-6 mouse hepatocytes. Lentivirus-mediated NF-Y overexpression in Hepa1-6 cells markedly increased sterol regulatory element binding protein 1 (SREBP1) and fatty acid synthase (FASN) expression compared with empty vector control cells. Conversely, CRISPR/Cas9-mediated knockdown of NF-Y subunit A (NF-YA) attenuated FASN and SREBP1 expression. Mechanistically, luciferase reporter gene assays and chromatin immunoprecipitation (ChIP) analysis indicated that NF-Y activates the transcription of SREBP1 by directly binding to the CCAAT regulatory sequence motif in the promoter. Overall, our results reveal a previously unrecognized physiological function of NF-Y in ALD by activating sterol regulatory element-binding protein 1 (SREBP1). Modulation of hepatic NF-Y expression may therefore offer an attractive therapeutic approach to manage ALD.

Novel Prognostic Models Predicting the Cancer-Specific Survival in Patients with Cutaneous Melanoma Based on Metastatic Lymph Node Status.

BACKGROUND: In cutaneous melanoma (CM), the present methods of lymph node (LN) staging have not sufficiently utilized the prognostic information of metastatic LNs. In this study, we aimed to construct prognostic nomograms based on the number of positive LNs (PLNs) and other clinicopathologic characteristics of CM patients. METHODS: Two prognostic models were constructed in the none/single PLN (PLNnone/single) and multiple PLN (PLNmultiple) cohorts, respectively. Independent prognostic predictors associated with cancer-specific survival (CSS) in the above two cohorts were integrated to construct two nomograms for predicting the probability of 2-, 4-, and 6-year CSS in the PLNnone/single and PLNmultiple cohorts. The nomograms were evaluated by the area under the receiver operating characteristic curves (AUC), the calibration plots, and the decision curve analyses (DCAs). RESULTS: A total of 31,065 CM cases were included in this study. Factors included in the prognostic nomogram for patients in the PLNnone/single cohort were age, sex, race, marital status, insurance, primary tumor site, T stage, and number of PLNs, while factors included in the nomogram for cases in the PLNmultiple cohort included age, sex, marital status, insurance, primary tumor site, T stage, and number of PLNs. The AUC values for 2-, 4-, and 6-year CSS in the validation group of the PLNnone/single cohort were 0.833, 0.811, and 0.818, respectively, while in the validation group of the PLNmultiple cohort, the AUC values for 2-, 4,- and 6-year CSS were 0.720, 0.723, and 0.745, respectively. Compared with the American Joint Committee on Cancer 7th edition staging system, our two nomograms showed better predictive values. Additionally, the calibration plots and DCA curves for 2-, 4-, and 6-year CSS prediction demonstrated good coordination and net benefit in both the PLNnone/single and PLNmultiple cohorts. CONCLUSION: Our nomograms, based on the number of PLNs and other clinicopathologic characteristics, showed good predictive ability for predicting the survival of CM patients.

A Novel Nomogram and Risk Classification System Predicting the Cancer-Specific Mortality of Patients with Initially Diagnosed Metastatic Cutaneous Melanoma.

BACKGROUND: Cutaneous melanoma and distant organ metastasis has varying outcomes. Considering all prognostic indicators in a prediction model might assist in selecting cases who could benefit from a personalized therapy strategy. OBJECTIVE: This study aimed to develop and validate a prognostic model for patients with metastatic melanoma. METHODS: A total of 1535 cases diagnosed with metastatic cutaneous melanoma (stage IV) were identified from the Surveillance, Epidemiology, and End Results database. Patients were randomly divided into the training (n = 1023) and validation (n = 512) cohorts. A prognostic nomogram was established based predominantly on results from the competing-risk regression model for predicting cancer-specific death (CSD). The area under the time-dependent receiver operating characteristic curve (AUC), calibration curves, and decision curve analyses (DCAs) were used to evaluate the nomogram. RESULTS: No significant differences were observed in the clinical characteristics between the training and validation cohorts. In the training cohort, patient-, tumor-, and treatment-related predictors of CSD for metastatic melanoma included age, sex, race, marital status, insurance, American Joint Committee on Cancer T and N stage, number of metastatic organs, surgical treatment, and chemotherapy. All these factors were used for nomogram construction. The time-dependent AUC values of the training and validation cohorts suggested a favorable performance and discrimination of the nomogram. The 6-, 12-, and 18-month AUC values were 0.706, 0.700, and 0.706 in the training cohort, and 0.702, 0.670, and 0.656 in the validation cohort, respectively. The calibration curves for the probability of death at 6, 12, and 18 months showed acceptable agreement between the values predicted by the nomogram and the observed outcomes in both cohorts. DCA curves showed good positive net benefits in the prognostic model among most of the threshold probabilities at different time points (death at 6, 12, and 18 months). Based on the total nomogram scores of each case, all patients were divided into the low-risk (n = 511), intermediate-risk (n = 512), and high-risk (n = 512) groups, and the risk classification could identify cases with a high risk of death in both cohorts. CONCLUSIONS: A predictive nomogram and a corresponding risk classification system for CSD in patients with metastatic melanoma were developed in this study, which may assist in patient counseling and in guiding clinical decision making for cases with metastatic melanoma.

Pre-Expanded Latissimus Dorsi Myocutaneous Flap for Total Scalp Defect Reconstruction.

Scalp defects can be caused by various factors, and reconstruction options for scalp defects include skin grafts, local flaps, tissue expanders, and free flaps. However, currently, it is widely accepted that the use of free flaps is the most feasible method for extensive scalp defect reconstruction. While multiple flaps have been used to reconstruct scalp defects, the reconstruction of total scalp defects still remains challenging. Pre-expansion of free flaps offers several advantages, including increasing flap size and thinning of the tissue for better contour, and is particularly important in scalp reconstruction. This report describes the successful management of total scalp defect reconstruction that involved the entire frontal, parietal, occipital, and temporal regions using a pre-expanded latissimus dorsi myocutaneous flap in a 40-year-old female patient. Over 2 years of follow-up, the transplanted flap survived well and the patient eventually achieved excellent cosmetic appearance, with satisfactory durable coverage. She was able to wear a hairpiece and hat without any wound breakdown. Our report indicates that microsurgery using pre-expanded latissimus dorsi myocutaneous flap transfer is a reliable and safe choice for total scalp reconstruction, allowing reconstruction with a single-flap, an excellent aesthetic effect, and abrasive resistance.

Serology Enhances Molecular Diagnosis of Respiratory Virus Infections Other than Influenza in Children and Adults Hospitalized with Community-Acquired Pneumonia.

Both molecular and serological assays have been used previously to determine the etiology of community-acquired pneumonia (CAP). However, the extent to which these methods are correlated and the added diagnostic value of serology for respiratory viruses other than influenza virus have not been fully evaluated. Using data from patients enrolled in the Centers for Disease Control and Prevention (CDC) Etiology of Pneumonia in the Community (EPIC) study, we compared real-time reverse transcription-PCR (RT-PCR) and serology for the diagnosis of respiratory syncytial virus (RSV), human metapneumovirus (HMPV), parainfluenza virus 1 to 3 (PIV1, PIV2, and PIV3), and adenovirus (AdV) infections. Of 5,126 patients enrolled, RT-PCR and serology test results were available for 2,023, including 1,087 children below the age of 18 years and 936 adults. For RSV, 287 (14.2%) patients were positive by RT-PCR and 234 (11.6%) were positive by serology; for HMPV, 172 (8.5%) tested positive by RT-PCR and 147 (7.3%) by serology; for the PIVs, 94 (4.6%) tested positive by RT-PCR and 92 (4.6%) by serology; and for AdV, 111 (5.5%) tested positive by RT-PCR and 62 (3.1%) by serology. RT-PCR provided the highest number of positive detections overall, but serology increased diagnostic yield for RSV (by 11.8%), HMPV (by 25.0%), AdV (by 32.4%), and PIV (by 48.9%). The method concordance estimated by Cohen's kappa coefficient (κ) ranged from good (for RSV; κ = 0.73) to fair (for AdV; κ = 0.27). Heterotypic seroresponses observed between PIVs and persistent low-level AdV shedding may account for the higher method discordance observed with each of these viruses. Serology can be a helpful adjunct to RT-PCR for research-based assessment of the etiologic contribution of respiratory viruses other than influenza virus to CAP.

Serologic cross-reactions between nucleocapsid proteins of human respiratory syncytial virus and human metapneumovirus.

Human respiratory syncytial virus (hRSV) and human metapneumovirus (hMPV) share virologic and epidemiologic features and cause clinically similar respiratory illness predominantly in young children. In a previous study of acute febrile respiratory illness in Bangladesh, we tested paired serum specimens from 852 children presenting fever and cough for diagnostic increases in titers of antibody to hRSV and hMPV by enzyme immunoassay (EIA). Unexpectedly, of 93 serum pairs that showed a ≥ 4-fold increase in titers of antibody to hRSV, 24 (25.8%) showed a concurrent increase in titers of antibody to hMPV; of 91 pairs showing an increase to hMPV, 13 (14.3%) showed a concurrent increase to hRSV. We speculated that common antigens shared by these viruses explain this finding. Since the nucleocapsid (N) proteins of these viruses show the greatest sequence homology, we tested hyperimmune antisera prepared for each virus against baculovirus-expressed recombinant N (recN) proteins for potential cross-reactivity. The antisera were reciprocally reactive with both proteins. To localize common antigenic regions, we first expressed the carboxy domain of the hMPV N protein that was the most highly conserved region within the hRSV N protein. Although reciprocally reactive with antisera by Western blotting, this truncated protein did not react with hMPV IgG-positive human sera by EIA. Using 5 synthetic peptides that spanned the amino-terminal portion of the hMPV N protein, we identified a single peptide that was cross-reactive with human sera positive for either virus. Antiserum prepared for this peptide was reactive with recN proteins of both viruses, indicating that a common immunoreactive site exists in this region.

A highly selective two-photon fluorescent probe for detection of cadmium(II) based on intramolecular electron transfer and its imaging in living cells.

A new quinoline-based probe was designed that shows one-photon ratiometric and two-photon off-on changes upon detecting Cd(2+) . It exhibits fluorescence emission at 407 nm originating from quinoline groups in Tris-HCl (25 mM, pH 7.40), H2 O/EtOH (8:2, v/v). Coordination with Cd(2+) causes quenching of the emission at 407 nm and simultaneously yields a remarkable redshift of the emission maximum to 500 nm with an isoemissive point at 439 nm owing to an intramolecular charge-transfer mechanism. Thus, dual-emission ratiometric measurement with a large redshift (Δλ=93 nm) and significant changes in the ratio (F500 /F439 ) of the emission intensity (R/R0 up to 27) is established. Moreover, the sensor H2 L displays excellent selectivity response, high sensitive fluorescence enhancement, and strong binding ability to Cd(2+). Coordination properties of H2 L towards Cd(2+) were fully investigated by absorption/fluorescence spectroscopy, which indicated the formation of a 2:1 H2 L/Cd(2+) complex. All complexes were characterized by X-ray crystallography, and TD-DFT calculations were performed to understand the origin of optical selectivity shown by H2 L. Two-photon fluorescence microscopy experiments have demonstrated that H2 L could be used in live cells for the detection of Cd(2+).

Effect of irradiation defects on the corrosion behaviors of steels exposed to lead bismuth eutectic in ADS: a first-principles study.

In accelerator driven systems (ADSs), steels will suffer not only from the irradiation damage produced by protons or neutrons, but also from the dissolution corrosion induced by the liquid lead-bismuth eutectic (LBE). In this work we investigate the interactions between LBE atoms (Pb, Bi) and the irradiation induced defects X (X is helium, vacancy or divacancy) in α-Fe based on first-principles calculations. It is found that LBE atoms repulse each other without irradiation defects, while they aggregate easily with the defects to form X-Pbn and X-Bin complexes. This indicates that the irradiation defects could promote the aggregation of LBE atoms in iron, especially Bi atoms. The total binding energies of the X-Pbn and X-Bin complexes increase with the number of Pb and Bi atoms, respectively. The origin of the total binding energies of the complexes is further discussed via the electronic structures and the distortion of the crystalline lattice. Finally, the concentration evolutions of the Vac-(Bi)n complexes and unbound vacancies with temperature are predicted by the mass action analysis. This work provides important information for the synergistic effect of irradiation and LBE corrosion on the steels in the ADSs, which can be used as basic parameters for further study.

Hydrofluoric Acid Controlled TiO2 Phase Transformation from Rutile to Anatase at Room Temperature and Their Photocatalytic Performance.

In this study, we first present rutile TiO2 superstructures could be successfully transformed into anatase TiO2 nanoparticles at room temperature by adjusting the amount of hydrofluoric acid (HF) used in aqueous solution. Photocatalytic experiments demonstrated that the as prepared anatase TiO2 exhibited better photocatalytic performance than that of rutile TiO2. We further studied the photocatalytic degradation of RhB on different TiO2 via active species trapping experiments and confirmed that the presence of surface F- on TiO2 was beneficial for the formation of *OH, which was thought to be mainly responsible for the enhancement of photocatalytic performance.