[Epidemiological Characteristics of Lung Cancer Incidence 
in the Tumor Registration Area of Gansu Province from 2010 to 2019].

BACKGROUND: Lung cancer is the malignant tumor with the highest incidence rate and the heaviest disease burden in China. In recent years, lung cancer has shown a high incidence trend, seriously affecting the health of the population. In this paper, we analyze the characteristics of lung cancer incidence in 2019 and the trend of incidence rate from 2010-2019 in the tumor registration area of Gansu province, in order to provide a reference basis for the development of lung cancer prevention and control strategies in Gansu province. METHODS: By analyzing the cases of lung cancer incidence in the tumor registration area of Gansu province in 2019, we calculated the incidence rate, medium incidence rate, world incidence rate and other related indexes; we used Joinpoint to calculate the annual percentage change (APC) for trend analysis. RESULTS: In 2019, a total of 3757 new cases of lung cancer were reported in Gansu province, accounting for 14.96% of all new malignant tumors. The incidence rate, medium incidence rate and world incidence rate and world rate of lung cancer were 40.52/105, 25.78/105, 25.86/105; and the cumulative rate of 0-74 years old, and the truncation rate of 35-64 years old were 3.23%, 40.03/105, respectively. The incidence of lung cancer rises with age, and is high in the age group of 40 years and above, and the incidence peaks in the male and female populations in the group of 75 years and above, and the group of 80 years and above, respectively. The crude incidence rate of lung cancer in the tumor registration area of Gansu province from 2010-2019 showed an overall increasing trend, and the rate of increase was relatively fast, with an APC 5.39% (P<0.05); Separately, according to gender, urban and rural areas, the incidence of lung cancer in all populations showed an increasing trend, and the APC of male, female, urban and rural populations were 4.98%, 6.39%, 6.26%, and 4.64%, respectively (all P<0.05). According to the trend analysis of lung cancer incidence rate by age group, only lung cancer incidence in the age group of 65 years and above increased at an annual average rate of 4.15% (P<0.05). CONCLUSIONS: The incidence rate of lung cancer in the tumor registration area of Gansu province from 2010 to 2019 shows a rising trend year by year, and there are differences in the incidence of lung cancer in people of different genders, regions and age groups, so comprehensive prevention and control work should be carried out for the key populations of lung cancer incidence.

Effective Combination of Targeted Therapies with Sonodynamic Treatment for Use in Exploring Differences in Therapeutic Efficacy across Organelle Targets.

Acoustic kinetic therapy systems that target specific organelles can improve the precision of a sonosensitizer, which is a perfect combination of targeted therapy and sonodynamic therapy (SDT) and plays an important role in current acoustic kinetic therapy. In this study, we loaded PpIX, a sonosensitizer, on targeted-functional carbon dots (CDs) via an amide reaction and then generated the mitochondria-targeted system (Mit-CDs-PpIX) and nucleus-targeted system (Nuc-CDs-PpIX), respectively, to deliver the sonosensitizer. Both systems exhibited minimal cytotoxicity in the absence of ultrasound stimulation. The efficacy of the targeted SDT systems was investigated using methylthiazol tetrazolium (MTT) assays, live/dead staining, flow cytometry, etc. Compared with the free PpIX and mitochondria-targeted system, the nucleus-targeted system is more potent in killing effect under ultrasound stimulation and induces apoptosis with higher intensity. To achieve the equal killing effect, the effective concentration of Nuc-CDs-PpIX is just one third of that of Mit-CDs-PpIX.

Systemic Immune-Inflammation Index is a Prognostic Predictor for Patients With Acute Ischemic Stroke Treated With Intravenous Thrombolysis.

OBJECTIVE: To investigate whether baseline systemic immune-inflammation index (SII) is associated with 3-month poor prognosis and early neurological outcomes in patients with acute ischemic stroke treated with intravenous thrombolysis. PATIENTS AND METHODS: A total of 221 consecutive patients were enrolled in the retrospective study. The primary endpoints were poor functional outcomes or death at 3 months. Secondary endpoints were early neurological deterioration (END) or symptomatic intracerebral hemorrhage within 24 hours. Receiver operating characteristic curve analyses was performed to assess the overall discriminative ability of SII in predicting the 4 endpoints. We also performed the Spearman correlation test to evaluate the relationship between SII and stroke severity. Univariable and multivariable logistic regression analyses were performed to evaluate the associations between SII and endpoints. RESULTS: The cutoff values of SII were 504.99×10 9 /L for predicting a 3-month poor prognosis (sensitivity, 70.9% and specificity, 69.6%), 524.47×10 9 /L for predicting 3-month death (sensitivity, 78.9% and specificity, 59.9%) and 504.99×10 9 /L for predicting END (sensitivity, 70.7% and specificity, 62.6%), respectively. A positive association between SII and the National Institutes of Health Stroke Scale was observed ( rs = 0.306, P < 0.001). Multivariable analyses indicated that SII was independently associated with 3-month poor prognosis [odds ratio (OR) = 5.384; 95% CI: 2.844-10.193; P < 0.001], 3-month death (OR = 2.592, 95% CI: 1.046-6.421, P = 0.040) and END (OR = 3.202, 95% CI: 1.796-5.707, P < 0.001). CONCLUSION: Increased baseline SII was associated with END and 3-month poor outcomes, and may act as a potential prognostic predictor for acute ischemic stroke patients treated with intravenous thrombolysis.

Factors related to dietary quality among older stroke high-risk population in Tianjin community, China: a multicenter study.

BACKGROUND: Stroke is a common and frequently-occurring disease in older people. It has the characteristics of high morbidity, high mortality, high recurrence rate and high disability rate. Most stroke risk studies are based on pathophysiology, however psychosocial factors such as diet quality are often understudied. The aim of this study was to assess stroke risk in urban community residents in Tianjin and investigate the factors that affect the dietary quality of older stroke high-risk populations. METHODS: Using a cross-sectional, multicenter study, recruit people aged 60 to 80 in Tianjin. Dietary intake data were obtained through a validated food frequency questionnaire, which were used to calculate Alternate Healthy Eating Index-2010 (AHEI-2010) and to analyze its association with sociodemographic characteristics, stroke risk factors and health marker variables. RESULTS: A total of 1068 participants from 4 community health service centers in Tianjin were recruited, including 300 low-risk individuals and 768 high-risk individuals. Compared with the low-risk group (62.75 ± 3.59), the AHEI-2010 mean score of the high-risk group (56.83 ± 6.54) was significantly lower. The top three most common risk factors among participants were dyslipidemia (80.3%), hypertension (60.6%), and physical inactivity (58.2%). Multiple logistic regression showed that diet quality was independently and significantly associated with stroke risk (OR = 0.765; 95%CI: 0.690-0.848, p < 0.001). CONCLUSION: The diet quality of high-risk stroke population in Tianjin is far from ideal. At the same time, public health knowledge needs to be disseminated and educated, especially among those at high risk of cerebrovascular disease, with a focus on improving psychosocial factors such as diet quality.

Efficient C2H2-selective separation in a microporous Zn(II)-based metal-organic framework via the dual-ligand strategy.

Implementing the dual-ligand strategy, a microporous Zn-based MOF 1 with nitro and amino groups was effectively produced. The activated interconnected pores of 1 exhibited high C2H2 uptake capacity and preferential adsorption behaviour for C2H2 over CO2, as identified by the experiments and simulations. This work provides a new approach for designing and synthesizing the MOFs with desired structures and properties by optimizing their pore environment via the dual-ligand strategy.

Seasonal Variation in Neurological Severity and Clinical Outcomes in Ischemic Stroke Patients　- A 9-Year Study of 5,238 Patients.

BACKGROUND: Because the effects of extreme weather conditions on stroke severity and outcomes are unclear, we evaluated seasonal variations in stroke severity and clinical outcomes.Methods and Results: Between 2012 and 2020 we enrolled 5,238 patients with acute ischemic stroke, who were divided into 4 seasons according to stroke onset: spring, summer, autumn and winter. We analyzed the effect of season on the severity and outcomes of all subjects. Multivariable analysis showed that the winter group had 1.234-fold increased risk of moderate-to-severe neurological deficits than the summer group (95% confidence interval (CI): 1.034-1.472, P=0.020). Compared with the summer group, the winter and the spring groups experienced 1.243- and 1.251-fold the risk of suffering from worse outcomes among all patients at 6-month follow-up (95% CI 1.008-1.534, P=0.042, 95% CI 1.013-1.544, P=0.037). The 1-year follow-up revealed similar results. Further comparison of each season in the 2012-2015 and 2016-2020 periods found that the proportion of poor outcomes in the latter autumn group was lower than that in the former time period, with significant differences in both 6-month and 1-year follow-up. CONCLUSIONS: The onset season was related to the severity and clinical outcomes of ischemic stroke. Patients with winter onset had more severe neurological deficits and worse outcomes than those with summer onset.

Short-term outcomes in patients with lung cancer-associated acute ischemic stroke.

BACKGROUND: To investigate the independent risk factors of poor short-term outcomes in patients with lung cancer-associated acute ischemic stroke (LCAIS) and use them to develop an index of prognosis LCAIS (pLCAIS) which could help clinicians identify patients at high risk for poor short-term outcomes. METHODS: We retrospectively enrolled patients with lung cancer-associated acute ischemic stroke and employed the 90D modified Rankin cale (mRS) to divide them into two groups: good outcomes (score 0-2) and poor outcomes (score 3-6). Propensity score matching (PSM) was used to remove confounding factors, and multivariable logistic regression analysis was used to analyze the independent risk factors of pLCAIS. The receiver operating characteristic (ROC) and area under the ROC curve (AUC) developed a multiple model combining the independent risk factors of pLCAIS. RESULTS: A total of 172 patients were included: 67 (38.9%) with good outcomes and 105 (61.1%) with poor outcomes. After using PSM, there were 33 cases in each group. The results showed that patients with poor short-term outcomes were significantly higher in D-dimer (OR = 1.001, 95% CI: 1.000-1.002, p = 0.048), CRP (OR = 1.078, 95% CI: 1.008-1.153, p = 0.028), and neutrophil count (OR = 14.673, 95% CI: 1.802-19.500, p = 0.012). The ROC curve, used to assess the diagnostic ability of binary classifiers, showed that the product of these three independent risk factors showed high sensitivity and specificity. CONCLUSION: In this study, we have identified three independent risk factors associated with poor short-term outcomes in pLCAIS: higher NC, CRP, and D-dimer levels. These findings may be helpful for clinicians in identifying poor short-term outcomes patients.

Improved performance of the pyrimidine-modified porous In-MOF and an in situ prepared composite Ag@In-MOF material.

A stable porous In-MOF 1 was prepared for the first time via an asymmetric N,O-containing (2-pyrimidin-5-yl)terephthalic acid (H2L). It was found that the 1,4-benzenedicarboxylate anions (bdc2-) were formed in the synthesis process of 1. Thus, another new isomorphic In-MOF 2 was formed by employing the H2bdc ligand in the synthesis process of 1. More importantly, when adding AgNO3 in the synthesis process of 1 and 2, only composite Ag@1 was obtained via the in situ reduction of Ag(I) to Ag NPs without additional reducing agent. MOF 1 and Ag@1 had great sorption capacity; in particular, 1 had remarkable dynamic selectivity for C2H2/CH4 and CO2/CH4, and they were also efficient catalysts for fixing CO2 and epoxides. It is hoped that this work may supply an effective strategy to build stable MOFs and composite Ag@MOF materials with excellent multifunctional applications.

Polydopamine coated Au-Pt nanorods: Enhanced photothermal properties and efficient reactive oxygen scavengers.

As an emerging cancer treatment strategy, photothermal therapy (PTT) is precise, controllable, minimally invasive, low cost and less toxic side effects, thus photothermal transduction agents have been extensively investigated in recent years. Noble metal nanomaterials with unique localized surface plasmon resonance (LSPR) effects are particularly suitable as photothermal transduction agent, but the currently developed precious noble metal nano photothermal transduction agents face serious problems such as complex synthesis process, poor photothermal performance and high biotoxicity. Moreover, the large amount of reactive oxygen species (ROS) produced during PTT treatment could cause irreversible damage to the healthy tissues surrounding the tumor. In this work, we deposited platinum (Pt) on the tips of gold nanorods (AuNRs) to form dumbbell-shaped Au-Pt bimetallic nanorods (AuPtNRs), and functionalized AuPtNRs with biocompatible polydopamine (PDA) to obtain AuPt@PDA. With 808 nm laser irradiation, the prepared AuPt@PDA exhibited excellent photothermal stability, and its photothermal conversion efficiency (PCE) reached 81.78%, which was significantly higher than that of AuNRs (52.32%) and AuPtNRs (78.76%). With low cytotoxicity, AuPt@PDA decreased cell viability from 91.12% to 39.36% after PTT on cancer cells in vitro, while significantly reducing intracellular ROS levels generated by heat stress. Therefore, the excellent photothermal properties, high cancer cell killing and ROS scavenging activity of AuPt@PDA in PTT could be an ideal candidate for improving therapeutic efficacy while reducing the risk of toxic side effects due to heat stress-induced ROS formation.

The effects of heatwaves and cold spells on patients admitted with acute ischemic stroke.

BACKGROUND: This study aimed to explore the effects of heatwaves and cold spells on blood pressure, thrombus formation, and systemic inflammation at admission in patients with ischemic stroke. METHODS: Data of patients with ischemic stroke who were admitted to the Second Hospital of Tianjin Medical University between May 2014 and March 2019 were reviewed, along with meteorological data from the same time period. A total of 806 clinically confirmed patients with ischemic stroke (34-97 years old) were included in the final analysis. Heatwaves and cold spells were defined as ≥2 consecutive days with average temperature >95th percentile (May-August) and <5th percentile (November-March), respectively. Coagulation parameters, inflammation indices, blood pressure, and neurological impairment were evaluated within 24 hours of admission. General linear and logistic regression models were created to investigate the relationships of heatwaves and cold spells with the examination results of patients with ischemic stroke at admission. RESULTS: After adjustment for potential environmental confounders, heatwaves were positively associated with high systolic blood pressure (SBP) (ß=8.693, P=0.019), diastolic blood pressure (DBP) (ß=3.665, P=0.040), reduced thrombin time (TT) (ß=-0.642, P=0.027), and activated partial thromboplastin time (APTT) (ß=-1.572, P=0.027) in ischemic stroke patients at admission. Cold spells were positively associated with high SBP (ß=5.277, P=0.028), DBP (ß=4.672, P=0.012), fibrinogen (ß=0.315, P=0.011), globulin (ß=1.523, P=0.011), and reduced TT (ß=-0.784, P<0.001) and APTT (ß=-1.062, P=0.024). Cold spells were also associated with a higher risk of respiratory infection [odds ratio (OR) =2.677, P=0.001]. CONCLUSIONS: Exposure to heatwaves or cold spells was associated with blood pressure and coagulation at admission in patients with ischemic stroke. Cold spells also resulted in higher levels of inflammation. These findings suggest that changes in coagulation, blood pressure, and inflammation may be the potential biological mechanisms underlying the cerebrovascular effects of exposure to extreme temperatures.

Recent progresses in luminescent metal-organic frameworks (LMOFs) as sensors for the detection of anions and cations in aqueous solution.

The discharge of excessive metal ions and anions into water bodies leads to the serious pollution of water and environment, which in turn has a certain impact on industry, agriculture, and human life. Because of the unique advantages of luminescent metal-organic frameworks (LMOFs), they have been successfully explored as various fluorescent probes to quickly and effectively detect these pollutants. This perspective not only introduces the design strategy and classification of LMOFs, especially the construction methods of water-stable LMOFs, but also reports the latest progresses in some LMOFs between 2016 and 2020 as well as expounds the mechanisms of LMOFs for detecting anions and cations. Moreover, the luminescence properties of LMOFs are related to the selection of metal ions, the structure of organic ligands, the pore size, and the interaction of guest molecules. Finally, the further development of LMOFs is summarized and prospected in this field.

Short-term effects of outdoor air pollution on acute ischaemic stroke occurrence: a case-crossover study in Tianjin, China.

OBJECTIVE: Ambient air pollution is associated with ischaemic stroke incidence. However, most of the previous studies used stroke-related hospital admission rather than stroke onset itself. This study aimed to evaluate the relationship between ambient air pollutant exposures and acute ischaemic stroke based on the timing of symptom onset. METHODS: A time-stratified, case-crossover analysis was performed among 520 patients who had ischaemic stroke admitted to the Second Hospital of Tianjin Medical University (Tianjin, China) between 1 April 2018 and 31 March 2019 (365 days). Daily air pollutant concentrations of particulate matter with aerodynamic diameter 2.5 µm, particulate matter with aerodynamic diameter 10 µm (PM10), sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone were obtained from fixed-site monitoring stations. We used conditional logistic regression to estimate OR and 95% CI corresponding to an increase in IQR of each air pollutant after adjusting for the effects of temperature and relative humidity. RESULTS: Overall, a higher risk of ischaemic stroke was found between April and September. During this period PM10 was associated with an increased risk of ischaemic stroke (1-day lag: OR=1.49, 95% CI 1.09 to 2.02; 3-day mean: OR=1.58, 95% CI 1.09 to 2.29) among patients between 34 and 70 years old. Positive associations were also observed between PM10 (1-day lag: OR=1.51, 95% CI 1.10 to 2.07; 3-day mean: OR=1.57, 95% CI 1.08 to 2.29), ozone (1-day lag: OR=1.83, 95% CI 1.16 to 2.87; 3-day mean: OR=1.90, 95% CI 1.06 to 3.42) and ischaemic stroke occurrence among those with hyperlipidaemia. CONCLUSION: Our results suggest that air pollution is associated with a higher risk of ischaemic stroke in younger people or people with hyperlipidemia. These findings still need to be further investigated.

Potential Impacts of Meteorological Variables on Acute Ischemic Stroke Onset.

PURPOSE: The effects of meteorological parameters on stroke occurrence remain debated. The aim of the study was to assess the association between meteorological parameters and ischemic stroke onset in cold seasons in Tianjin. PATIENTS AND METHODS: Patients with acute ischemic stroke (946) were identified by standard sampling from one stroke unit in the Second Hospital of Tianjin Medical University, Tianjin, China, from 10/1/2014 to 4/30/2019. Generalized linear Poisson regression models were used to explore the effect of meteorological parameters (air temperature, barometric pressure, and relative humidity) on daily ischemic stroke onset after adjusting for air pollutants, day of week, and public holiday. RESULTS: The results showed that ischemic stroke onset was positively associated with the diurnal variation of temperature (ß coefficient: 0.020, 95% CI [0.001, 0.038] p<0.05). Significant positive correlation between ischemic stroke onset and barometric pressure (mean, minimum) was found (ß coefficient: 0.010, 95% CI [0.001,0.019] p<0.05; 0.010, 95% CI [0.001,0.019] p<0.05). The subgroup analysis considering age and gender difference showed that the older and the female were more vulnerable to weather conditions. CONCLUSION: Our study demonstrated that there was a measurable effect of weather parameters on daily ischemic stroke onset in colder seasons, suggesting that meteorological variables may, at least in part, play as risk factors for ischemic stroke onset, especially for the aging and female population.

Diagnosis of electrically active defects in CH3NH3PbI3 perovskite solar cells via admittance spectroscopy measurements.

The defect properties of CH3NH3PbI3 solar cells with efficiencies ranging from 7.70% to 12.51% were investigated using admittance spectroscopy measurements. Trap levels of the same kind with activation energies varied in the range of 0.16-0.23 eV above the valence band were found for different samples and identified as an interface-type defect. Moreover, the defect parameters, including the capture cross section of the holes, capture lifetime of the holes, and defect density, were extracted, and their relationships with the cell efficiencies were investigated. The results indicated that, compared with other parameters, defect density is a critical factor for CH3NH3PbI3 solar cell performance.

Giant reduction of the random lasing threshold in CH3NH3PbBr3 perovskite thin films by using a patterned sapphire substrate.

Hybrid organic-inorganic metal halide perovskites are currently arousing enthusiasm and stimulating huge activity across several fields of optoelectronics due to their outstanding properties. In this study, we present the incoherent random lasing (RL) emissions from CH3NH3PbBr3 perovskite thin films on both planar fluorine-doped tin oxide (FTO) substrates and patterned sapphire substrates (PSSs). A detailed examination of the spectral evolution indicates that inelastic exciton-exciton scattering called P-emission is the most plausible mechanism accounting for the lasing emissions. The RL threshold of the perovskite films on PSSs is found to be effectively reduced by more than one order of magnitude from 2.55 to 0.15 µJ per pulse compared to that on FTO substrates. The giant threshold reduction is ascribed to the enhanced random scattering of light and the photon recycling induced by the multireflection processes at the perovskite/PSS interface, which increases the likelihood that the inoperative random rays will re-enter the possible optical loops formed among the perovskite particles, resulting in considerable optical resonance enhancement. The simulation results reveal that the light extraction efficiency on the top facet of the perovskites is significantly increased by approximately 155% by utilizing the PSS instead of the FTO substrate. Moreover, the first direct experimental observation of the multireflection phenomenon of light, as well as the dynamic processes of photon propagation in the composite PSS structure, is presented by Kerr-gate-based time-resolved photoluminescence. Our results provide an effective strategy to achieve high-performance perovskite random lasers and novel light-emitting devices for speckle-free full-field imaging and solid-state lighting applications, by introducing ingeniously designed periodic nano-/microscale optical structures.

Effects of substrate temperature on material and photovoltaic properties of magnetron-sputtered Sb2Se3 thin films.

We studied the material and photovoltaic properties of Sb2Se3 thin films fabricated by a magnetron-sputtering method at different substrate temperatures. The films had good crystallinity at substrate temperatures over 300°C. The band-gap energies between 1.1 and 1.5 eV of the films, which were obtained by transmittance measurements, initially decreased and then increased slowly with increasing temperature. Solar cells based on the films with structures of ITO/CdS/Sb2Se3/Au were fabricated, and the substrate temperature had significant effects on the device performance. Low crystal quality at low temperature resulted in a low short-circuit current (Jsc), while high temperature caused Se deficiency due to evaporation, which decreased the open-circuit voltage (Voc). The best solar cell performance achieved an efficiency of 0.84% with a Voc of 0.27 V and Jsc of 9.47 mA/cm2 when the substrate temperature was 325°C.

Antibody-Drug Conjugates Derived from Cytotoxic seco-CBI-Dimer Payloads Are Highly Efficacious in Xenograft Models and Form Protein Adducts In Vivo.

This work discloses the first examples of antibody-drug conjugates (ADCs) that are constructed from linker-drugs bearing dimeric seco-CBI payloads (duocarmycin analogs). Several homogeneous, CD22-targeting THIOMAB antibody-drug conjugates (TDCs) containing the dimeric seco-CBI entities are shown to be highly efficacious in the WSU-DLCL2 and BJAB mouse xenograft models. Surprisingly, the seco-CBI-containing conjugates are also observed to undergo significant biotransformation in vivo in mice, rats, and monkeys and thereby form 1:1 adducts with the Alpha-1-Microglobulin (A1M) plasma protein from these species. Variation of both the payload mAb attachment site and length of the linker-drug is shown to alter the rates of adduct formation. Subsequent experiments demonstrated that adduct formation attenuates the in vitro antiproliferation activity of the affected seco-CBI-dimer TDCs, but does not significantly impact the in vivo efficacy of the conjugates. In vitro assays employing phosphatase-treated whole blood suggest that A1M adduct formation is likely to occur if the seco-CBI-dimer TDCs are administered to humans. Importantly, protein adduct formation leads to the underestimation of total antibody (Tab) concentrations using an ELISA assay but does not affect Tab values determined via an orthogonal LC-MS/MS method. Several recommendations regarding bioanalysis of future in vivo studies involving related seco-CBI-containing ADCs are provided based on these collective findings.

Effect of Cu/Ga ratio on deep-level defects in CuGaSe2 thin films studied by photocapacitance measurements with two-wavelength excitation.

The effect of the Cu/Ga ratio on properties of deep-level defects in CuGaSe2 thin films were studied, using photocapacitance methods with two-wavelength excitation. The transient photocapacitance method, using a monochromatic probe light, determined two kinds of defects located at 0.8 eV and 1.5 eV above the valence band, respectively, the positions of which kept almost constant regardless of Cu/Ga ratio. In addition to the probe light, laser light with a wavelength of 1550 nm corresponding to 0.8 eV was then used to study the saturation effect of the deep-level defect at 0.8 eV above the valence band. The results suggest that the defect level at 0.8 eV acts as a recombination center at room temperature, and it becomes more effective in CuGaSe2 films with a lower Cu/Ga ratio.

SERS Assay for Copper(II) Ions Based on Dual Hot-Spot Model Coupling with MarR Protein: New Cu2+-Specific Biorecognition Element.

We have developed a rapid and ultrasensitive surface-enhanced Raman scattering (SERS) assay for Cu2+ detection using the multiple antibiotic resistance regulator (MarR) as specific bridging molecules in a SERS hot-spot model. In the assay, Cu2+ induces formation of MarR tetramers, which provide Au nanoparticle (NP)-AuNP bridges, resulting in the formation of SERS hot spots. 4-Mercaptobenzoic acid (4-MBA) was used as a Raman reporter. The addition of Cu2+ increased the Raman intensity of 4-MBA. Use of a dual hot-spot signal-amplification strategy based on AuNP-AgNP heterodimers combined through antigen-antibody reactions increased the sensitivity of the sensing platform by 50-fold. The proposed method gave a linear response for Cu2+ detection in the range of 0.5-1000 nM, with a detection limit of 0.18 nM, which is 5 orders of magnitude lower than the U.S. Environmental Protection Agency limit for Cu2+ in drinking water (20 µM). In addition, all analyses can be completed in less than 15 min. The high sensitivity, high specificity, and rapid detection capacity of the SERS assay therefore provide a combined advantage over current assays.

Investigation of deep-level defects in CuGaSe2 thin-film solar cells using photocapacitance methods.

Properties of deep-level defects in CuGaSe2 thin-film solar cells were investigated using photocapacitance methods. By measuring the transient photocapacitance spectra, a deep-level defect centered at around 0.8 eV above the valence band and a defect band located around 1.54 eV above the valence band were determined. A configuration coordinate model was used to explain the thermal quenching effect of the two defects. By measuring the steady-state photocapacitance, a fast increase, followed by a slow increase, was observed in the photocapacitance transient when the sample was illuminated by light with a photon energy of 0.8 eV at low temperature. Upon re-exposure by sub-bandgap light, an extra slow decrease in photocapacitance transient was observed. These observations were interpreted using a configuration coordinate model assuming two states for the 0.8 eV defect: a stable state D and a metastable state D* with a large lattice relaxation. The variation of the photocapacitance transients was attributed to the different optical transition processes of carriers between the two states of the 0.8 eV defect and the valence and conduction bands.