Ag Nanoparticles@Au Nanograting Array as a 3D Flexible and Effective Surface-Enhanced Raman Scattering Substrate.

Surface-enhanced Raman scattering (SERS) is a powerful analytical technique for chemical identification, but it remains a great challenge to realize the large-scale and well-controlled fabrication of sensitive and repeatable SERS substrates. Here, we report a facile strategy to fabricate centimeter-sized periodic Au nanograting (Au-NG) decorated with well-arranged Ag nanoparticles (Ag-NPs) (denoted as Ag-NPs@Au-NG) as a three-dimensional (3D) flexible hybrid SERS substrate with high sensitivity and good reproducibility. The Au-NG patterns with periodic ridges and grooves are fabricated through nanoimprint lithography by employing a low-cost digital versatile disc (DVD) as a master mold, and the Ag-NPs are assembled by a well-controlled interface self-assembly method without any coupling agents. Multiple coupling electromagnetic field effects are created at the nanogaps between the Ag-NPs and Au-NG patterns, leading to high-density and uniform hot spots throughout the substrate. As a result, the Ag-NPs@Au-NG arrays demonstrate an ultrahigh SERS sensitivity as low as 10-13 M for rhodamine 6G with a high average enhancement factor (EF) of 1.85 × 108 and good signal reproducibility. For practical applications, toxic organic pollutants including crystal violet, thiram, and melamine have been successfully detected with high sensitivity at a low detection limit, showing a good perspective in the rapid detection of toxic organic pollutants.

Phase-Tunable Molybdenum Boride Ceramics as an Emerging Sensitive and Reliable SERS Platform in Harsh Environments.

Traditional surface-enhanced Raman scattering (SERS) sensors rely heavily on the use of plasmonic noble metals, which have limitations due to their high cost and lack of physical and chemical stability. Hence, it is imperative to explore new materials as SERS platforms that can withstand high temperatures and harsh conditions. In this study, the SERS effect of molybdenum boride ceramic powders is presented with an enhancement factor of 5 orders, which is comparable to conventional noble metal substrates. The molybdenum boride powders synthesized through liquid-phase precursor and carbothermal reduction have ß-MoB, MoB2 , and Mo2 B5 phases. Among these phases, ß-MoB demonstrates the most significant SERS activity, with a detection limit for rhodamine 6G (R6G) molecules of 10-9  m. The impressive SERS enhancement can be attributed to strong molecule interactions and prominent charge interactions between R6G and the various phases of molybdenum boride, as supported by theoretical calculations. Additionally, Raman measurements show that the SERS activity remains intact after exposure to high temperature, strong acids, and alkalis. This research introduces a novel molybdenum boride all-ceramic SERS platform capable of functioning in harsh conditions, thereby showing the promising of boride ultrahigh-temperature ceramics for detection applications in extreme environments.

Spontaneous Redox-Reaction-Driven Growth of Ag Nanoparticles on Co(OH)2 Nanoflower Arrays for Surface-Enhanced Raman Scattering.

A simple and reliable method is developed to fabricate Ag-nanoparticle-decorated Co(OH)2 nanoflowers grafted on polyacrylonitrile (PAN) nanopillar arrays as uniform and sensitive surface-enhanced Raman scattering (SERS) substrates. First, Co(OH)2-nanosheet-assembled nanoflowers are achieved on the highly uniform PAN nanopillar arrays via electrochemical deposition. Then, Ag nanoparticles (Ag-NPs) are decorated onto the Au-nanoparticle-precoated Co(OH)2 nanoflowers based on a spontaneous redox reaction (SRR) between the silver ions and Co(OH)2 nanosheets at room temperature. Ag-NPs can be successfully in situ synthesized on the Co(OH)2 nanoflowers, and Au nanoparticles precoated on the surface of the Co(OH)2 nanosheets can ensure that the Co(OH)2 nanoflower structure does not collapse. Because of the highly uniform PAN nanopillar arrays and the high-density sub-10 nm gaps between the neighboring Ag-NPs on the surface of the Co(OH)2 nanoflowers, the hierarchical three-dimensional Ag@Co(OH)x grown on PAN nanopillar arrays can produce a reproducible and sensitive SERS effect. To verify the SERS performance of the substrate, 4-aminothiophenol (4-ATP) is used as the probe molecule, and the Ag@Co(OH)x grown on PAN nanopillar arrays is employed as the SERS substrate. As a result, 4-ATP concentrations as low as 10-10 M can still be identified, exhibiting high SERS activity. Additionally, the relative standard deviation value of the main characteristic peak of 10-5 M 4-ATP is 9.43%, indicating good uniformity of the SERS signal of the substrate. The SRR between silver ions and Co(OH)2 can provide a simple route to prepare heterostructures as SERS substrates, which has great potential for application in the field of analysis.

Plasmonic hot electrons for sensing, photodetection, and solar energy applications: A perspective.

In plasmonic metals, surface plasmon resonance decays and generates hot electrons and hot holes through non-radiative Landau damping. These hot carriers are highly energetic, which can be modulated by the plasmonic material, size, shape, and surrounding dielectric medium. A plasmonic metal nanostructure, which can absorb incident light in an extended spectral range and transfer the absorbed light energy to adjacent molecules or semiconductors, functions as a "plasmonic photosensitizer." This article deals with the generation, emission, transfer, and energetics of plasmonic hot carriers. It also describes the mechanisms of hot electron transfer from the plasmonic metal to the surface adsorbates or to the adjacent semiconductors. In addition, this article highlights the applications of plasmonic hot electrons in photodetectors, photocatalysts, photoelectrochemical cells, photovoltaics, biosensors, and chemical sensors. It discusses the applications and the design principles of plasmonic materials and devices.

Medication adherence to antiretroviral therapy among newly treated people living with HIV.

BACKGROUND: Free antiretroviral therapy has been implemented in China since 2004, but adherence to antiretroviral therapy among people living with HIV is suboptimal. The effectiveness of antiretroviral therapy is subject to medication adherence, which decreases with prolonged treatment times. The aim of this study was to investigate medication adherence and related factors among people living with HIV with newly initiated antiretroviral therapy. METHODS: This observational study was conducted in consecutive samples of people living with HIV who had newly initiated antiretroviral therapy. Participants were recruited between March 1, 2013, and August 31, 2014, from the local Center for Disease Control and Prevention and Infectious Disease hospital in a capital city in central China. A standard set of questionnaires was adopted, including the Community Programs for Clinical Research on AIDS Antiretroviral Medications and Self-Report Questionnaire (CPCRA), the Patient Health Questionnaire-9 (PHQ-9) and the 7-item Generalized Anxiety Disorder Scale (GAD-7). T-test, Chi square test and multivariate logistic regression analysis with backward stepwise were performed to explore factors that might influence medication adherence. RESULTS: Of the 207 participants, 85.5% of the participants (177/207) were categorized with good adherence, and 14.5% (30/207) with poor adherence. The multivariate logistic regression analyses showed that participants with positive depression (OR = 5.95, 95% CI: 2.34-15.11) and without disclosure of their HIV status to others (OR = 2.62, 95% CI: 1.06-6.50) were more susceptible to poor adherence. CONCLUSIONS: One-sixth of the participants reported suboptimal medication adherence within the first 6 months. Factors associated with poor adherence included non-disclosure of their HIV status, had positive depression. Tailored interventions, such as effective psychological coping strategies, should be implemented for people living with HIV with newly initiated antiretroviral therapy to improve their medication adherence.

Development and effectiveness of a mobile phone application conducting health behavioral intervention among men who have sex with men, a randomized controlled trial: study protocol.

BACKGROUND: Behavioral intervention is a key approach to HIV prevention among men who have sex with men (MSM). Widespread use of mobile phones provide us with novel opportunities to decrease HIV infection and transmission of MSM. The objective of the study was to design and develop a mobile phone application (app) aims to conduct behavioral intervention to MSM and to evaluate the efficacy of the app-based intervention compared to usual care, to analyze cost-effectiveness and mechanism of the intervention. METHODS: This study involves 2 phases, phase 1 use qualitative method and phase 2 is a randomized controlled trial lasting for 18 months, they will be conducted in Chagnsha, Hunan Province, China. Phase 1 is to design and develop the app, procedures including retrieval of domestic apps related to prevention and treatment about HIV and sexually transmitted diseases (HIV/STDs), personal interviews with MSM about preferences and functional needs of the HIV prevention app, multidisciplinary experts focused group discussions of the app, software engineers' development and users test of the app will be performed. In phase 2, we will recruit 800 MSM by cooperating with the local center of disease control and prevention and nongovernmental organizations, and divide them into intervention and control group evenly. Intervention group participants will receive app-based HIV prevention. Control group participants will be provided with usual care including HIV/STDs knowledge brochure and free voluntary counseling services. Data will be collected at baseline, 6, 12 and 18 months since subject's participation. Effectiveness of the intervention includes HIV/STDs infection rates, adherence to regularly HIV testing, sexual risk behavior, consistent condom use and relative risk of HIV infection. Cost-effectiveness will be analyzed by decision-analytic modeling, and mechanism analysis of this app-based intervention will be performed by path analysis. DISCUSSION: This will be the first study of its kind in China to develop an app and implement app-based HIV prevention intervention among MSM. It is of great potential to determine whether app-based intervention is a cost-effective way to decrease HIV infection among MSM and explore intervention mechanism with an accurate method. TRIAL REGISTRATION: Chinese Clinical Trial Register ( ChiCTR-IOR-15006724 ). Registered 10 July 2015.

A flexible transparent Ag-NC@PE film as a cut-and-paste SERS substrate for rapid in situ detection of organic pollutants.

This report presents a simple and inexpensive fabrication approach to a flexible transparent composite film as a "cut-and-paste" surface-enhanced Raman scattering (SERS) substrate for in situ detection of organic pollutants. First, a self-assembled monolayer of Ag-nanocubes (Ag-NCs) is obtained at the air/water interface. Then, the Ag-NC monolayer is retrieved onto a flexible transparent polyethylene (PE) film to achieve an Ag-NC@PE composite film as a flexible SERS substrate. As the Ag-NCs in the monolayer are closely and uniformly packed on the PE film, the Ag-NC@PE composite film shows high SERS-activity with good signal homogeneity and reproducibility. Furthermore, the flexible transparent Ag-NC@PE composite film is "cut into" small pieces and directly "pasted" onto contaminated fruits for in situ SERS detection, as a result 10 nM thiram, 1 µM 4-polychlorinated biphenyl and 10 nM methyl parathion contaminants on oranges are detected, respectively. Therefore the Ag-NC@PE composite film is an inexpensive and effective SERS substrate for rapid in situ detection of organic pollutants in aqueous solutions, on fruits and other solid objects.

An ordered array of hierarchical spheres for surface-enhanced Raman scattering detection of traces of pesticide.

An ordered array of hierarchically-structured core-nanosphere@space-layer@shell-nanoparticles has been fabricated for surface-enhanced Raman scattering (SERS) detection. To fabricate this hierarchically-structured chip, a long-range ordered array of Au/Ag-nanospheres is first patterned in the nano-bowls on the planar surface of ordered nanoporous anodic titanium oxide template. A ultra-thin alumina middle space-layer is then conformally coated on the Au/Ag-nanospheres, and Ag-nanoparticles are finally deposited on the surface of the alumina space-layer to form an ordered array of Au/Ag-nanosphere@Al2O3-layer@Ag-nanoparticles. Finite-difference time-domain simulation shows that SERS hot spots are created between the neighboring Ag-nanoparticles. The ordered array of hierarchical nanostructures is used as the SERS-substrate for a trial detection of methyl parathion (a pesticide) in water and a limit of detection of 1 nM is reached, indicating its promising potential in rapid monitoring of organic pollutants in aquatic environment.

Interleukin-27 as a Novel Biomarker for Early Cardiopulmonary Failure in Enterovirus 71-Infected Children with Central Nervous System Involvement.

Enterovirus 71 (EV71) is a major pathogen for severe hand, foot, and mouth disease (HFMD), which leads to severe neurological complications and has high morbidity and mortality. Reliable biomarker for the prediction of deterioration in EV71-infected children with central nervous system (CNS) involvement may reduce the cardiopulmonary failure and mortality. Here, we found that serum IL-27 levels were significantly higher in stage III EV71-infected HFMD patients with early cardiopulmonary failure and strong correlation with CRP levels. IL27p28 polymorphisms (rs153109, rs17855750, and rs181206) did not influence IL-27 production, and these three SNPs were not associated with EV71 infection risk and clinical stage. IL-27 can be used as an prediction indicator for early cardiopulmonary failure in EV71-infected children with CNS involvement.

Ag-nanoparticle-decorated Ge nanocap arrays protruding from porous anodic aluminum oxide as sensitive and reproducible surface-enhanced Raman scattering substrates.

We report on the fabrication of Ag nanoparticle (Ag NP) decorated germanium (Ge) nanocap (Ag-NPs@Ge-nanocap) arrays protruding from highly ordered porous anodic aluminum oxide (AAO) template as highly sensitive and uniform surface-enhanced Raman scattering (SERS) substrates. The hybrid SERS substrates are fabricated via a combinatorial process of AAO template-assisted growth of Ge nanotubes with each tube having a hemispherical nanocap on the AAO pore bottom, wet chemical etching of the remaining aluminum and the AAO barrier layer to expose the Ge nanocaps, and sputtering Ag NPs on the Ge nanocap arrays. Because sufficient SERS "hot spots" are created from the electromagnetic coupling among the Ag NPs on the Ge nanocap and the highly ordered Ge nanocap arrays also have semiconducting chemical supporting enhancement, the hybrid SERS substrates have high SERS sensitivity and good signal reproducibility. Using the hybrid SERS substrates, Rhodamine 6G with a concentration down to 10(-11) M is identified, and one congener of highly toxic polychlorinated biphenyls with a concentration as low as 10(-6) M is also recognized, showing great potential for SERS-based rapid detection of organic pollutants in the environment.

[Emotional problems and related factors in patients with HIV/AIDS].

OBJECTIVE: To investigate the prevalence and related factors of emotional problems of newly identified patients with HIV/AIDS in Changsha, Hunan Province, and to provide scientific evidence for the mental health intervention in this special population. METHODS: A total of 370 patients with HIV/AIDS who were newly identified by the Center for Disease Prevention and Control in Changsha City from March 1, 2013 to February 28, 2014 were investigated. Self-designed questionnaire, Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder Scale (GAD-7), HIV/AIDS Stress Scale and Social Support Rating Scale (SSRS) were performed to assess the prevalence of depression, the anxiety symptoms, the HIV related stress and the status of social support. RESULTS: The prevalence of depression and anxiety were 40.3% (PHQ-9 ≥ 10 points) and 30.5% (GAD-7 ≥ 10 points), respectively. Severe depressive symptoms (PHQ-9≥20 points) and severe anxiety (GAD-7 ≥ 15 points) accounted for 8.1% and 14.3%, respectively. Hierarchical regression analysis showed that the status of employment (b=-3.407, P<0.001; b=-2.799, P=0.001), the sexual orientation (b=1.903, P=0.008; b=1.314, P=0.034), the resident status (b=-1.995, P=0.012; b=-2.167, P=0.002), the emergence of HIV-related symptoms(b=4.578, P<0.001; b=3.652, P<0.001) and the HIV related stress (b=0.081, P<0.001; b=0.090, P<0.001) were the predictors for both depressive and anxious emotional problems whereas the social support (b=-0.046, P=0.044) was the predictor for depressive emotional problems. Both anxiety (ΔR2=54.7%, P<0.001) and depression (ΔR2=55.8%, P<0.001) were strong predictors for patients with HIV/AIDS. CONCLUSION: Depression and anxiety are prevalent among the newly identified patients with HIV/ AIDS. Psychosocial support and basic mental health services should be integrated into the current HIV/AIDS care system.

Biomass-derived lightweight SiC aerogels for superior thermal insulation.

Silicon carbide (SiC) aerogels, which possess unique porous structure and high ablation resistance, show great potential as thermal insulation materials, but their wide application is limited by expensive and cumbersome synthetic procedures. Therefore, it is pivotal to develop a facile, versatile, and cost-effective method for producing SiC aerogels. Herein, we have successfully prepared ultra-light SiC nanowire aerogels (SNWAs) boasting remarkably low thermal conductivity, using biomass-derived carbon templates (BCTs) through a direct carbothermal reduction method. The BCTs obtained by simply carbonizing freeze-dried eggplants can serve not only as the carbon sources but also as the templates for the in situ growth of SiC nanowires. The resultant three-dimensional (3D) SNWAs possess various porous structures, incorporating the original micro-sized pores inherited from the eggplant and nano-sized pores constructed from interconnected SiC nanowires. These multi-scale pore structures bestow SNWAs with lower gas-phase heat conduction characteristics. Besides, the numerous stacking faults and heterojunctions present in the SiC nanowires play a key role in obstructing the solid-phase heat transfer and reinforcing the SiC skeleton. As a result, the SNWAs show an exceptionally low thermal conductivity, measuring 0.0149 W m-1 K-1 at room temperature, and maintain this low value (0.0256 W m-1 K-1) even at 500 °C. Remarkably, even after being exposed to air at 1200 °C for 2 h, the SNWAs maintain a low thermal conductivity of 0.0226 W m-1 K-1. Such low-cost and effective preparation of biomass-derived SiC aerogels is anticipated to pave a new avenue for the development of advanced thermal insulators.

Self-Confined Dewetting Mechanism in Wafer-Scale Patterning of Gold Nanoparticle Arrays with Strong Surface Lattice Resonance for Plasmonic Sensing.

A self-confined solid-state dewetting mechanism is reported that can fundamentally reduce the use of sophisticated nanofabrication techniques, enabling efficient wafer-scale patterning of non-closely packed (ncp) gold nanoparticle arrays. When combined with a soft lithography process, this approach can address the reproducibility challenges associated with colloidal crystal self-assembly, allowing for the batch fabrication of ncp gold arrays with consistent ordering and even optical properties. The resulting dewetted ncp gold nanoparticle arrays exhibit strong surface lattice resonance properties when excited in inhomogeneous environments under normal white-light incidence. With these SLR properties, the sensitive plasmonic sensing of molecular interactions is achieved using a simple transmission setup. This study will advance the development of miniaturized and portable devices.

Kirkendall effect induced ultrafine VOOH nanoparticles and their transformation into VO2(M) for energy-efficient smart windows.

Vanadium dioxide (VO2) has received widespread attention for application in energy-efficient smart windows because of its distinct thermochromic property in the near-infrared region during the reversible metal-insulator phase transition. In this study, lepidocrocite VOOH ultrafine nanoparticles (NPs) with a diameter less than 30 nm were prepared by a mild and efficient hydrothermal method, and the Kirkendall effect played a vital role in the growth of the VOOH NPs. It was found that VOOH could be transformed into VO2via a subsequent annealing treatment during which the size and morphology of VOOH are well preserved even though the annealing temperature is up to 500 °C. The ultrafine VO2 NPs are crucial for achieving excellent nanothermochromic performance with a luminous transmittance (Tlum) up to 56.45% and solar modulation ability (ΔTsol) up to 14.95%. The environmental durability is well improved by coating VO2 NPs with an SiO2 shell as confirmed via progressive oxidation and acid corrosion experiments. Meanwhile, the Tlum of the VO2@SiO2 film is further increased from 56.45% to 62.29% while the ΔTsol remained unchanged. This integrated thermochromic performance presents great potential for the development of VO2-based smart windows.

Flexible 3D Substrate of Ag Nanoparticle-Loaded Carbon Aerogels with Outstanding Surface-Enhanced Raman Scattering Performance.

Surface-enhanced Raman scattering (SERS), an ultra-sensitive and non-destructive analytic technique, has attracted wide attention from the scientific community. Despite its rapid development, limited hotspots on the SERS substrates have restricted their potential in practical applications. Herein, we developed a facile method to fabricate a flexible three-dimensional (3D) SERS substrate composed of silver nanoparticles (Ag NPs)-loaded carbon aerogels (CAs). Such a flexible Ag NPs/CAs substrate exhibited numerous hotspots, which can facilely be adjusted not only by tuning the density of Ag NPs but also by controlling the bending degree of the flexible substrate. In addition, the influence of hotspots on the local electric field enhancement was investigated by theoretical calculations. Moreover, the 3D network structure of the CAs with a large specific surface area and strong adsorption ability can improve the capture of target molecules. Consequently, the optimal Ag NPs/CAs substrate has a low detection limit of 10-12 M for rhodamine 6G molecules as well as good repeatability. Furthermore, based on the good performance of SERS detection of the Ag NPs/CAs substrate, it can also be practically used for the detection of thiram molecules on the surface of cherry tomatoes. Such a flexible 3D Ag NPs/CAs substrate has great potential for practical environmental monitoring applications.

In-Situ Monitoring the SERS Spectra of para-Aminothiophenol Adsorbed on Plasmon-Tunable Au@Ag Core-Shell Nanostars.

Plasmon-induced photocatalysis on noble metal surfaces has attracted broad attention due to its application in sunlight energy conversion, while the selectivity of plasmonic platforms remains unclear. Herein, we present the controlled plasmon-mediated oxidation of para-aminothiophenol (p-ATP) by employing Au@Ag core-shell nanostars with tunable tip plasmons in visible-near-infrared range as reactors. In-situ Raman measurements indicate that Au@Ag core-shell nanostars essentially promote the conversion of p-ATP to 4,4'-dimercaptoazobenzene (DMAB) due to hot carriers excited by localized surface plasmon resonance. Au@Ag nanostars with plasmon modes under resonant light excitation suggested higher catalytic efficiency, as evidenced by the larger intensity ratios between 1440 cm-1 (N=N stretching of DMAB) and 1080 cm-1 shifts (C-S stretching of p-ATP). Importantly, the time-dependent surface-enhanced Raman scattering spectra showed that the conversion efficiency of p-ATP was mainly dictated by the resonance condition between the tip plasmon mode of Au@Ag core-shell nanostars and the excitation light, as well as the choice of excitation wavelength. These results show that plasmon bands of metal nanostructures play an important role in the efficiency of plasmon-driven photocatalysis.

SERS spectral evolution of azo-reactions mediated by plasmonic Au@Ag core-shell nanorods.

The mechanism and application of localized surface plasmon resonance induced photocatalytic reactions remain an issue of interest. In this work, we used Au@Ag core-shell nanorods as a platform for plasmon-driven photocatalysis, which was in situ investigated by surface-enhanced Raman scattering (SERS) spectroscopy. The para-aminothiophenol (PATP) and para-nitrothiophenol (PNTP) adsorbed on the nanorods were irradiated with different excitation wavelengths (633 nm, 785 nm) and transformed into 4,4'-dimercaptoazobenzene (DMAB) as evidenced by the emerging Raman peaks at 1142 cm-1, 1390 cm-1, 1440 cm-1, and 1477 cm-1, corresponding to hot carrier dominated oxidation of PATP and reduction of PNTP. Preliminary azo-reaction kinetics and in situ SERS measurements were conducted by comparing the relative intensity ratio of SERS peaks at 1440 cm-1 (DMAB stretching of N[double bond, length as m-dash]N) and 1080 cm-1 (C-S stretching of PATP and PNTP). These results indicate that the catalytic efficiency was dominated by the excitation wavelength as well as the resonance condition between the plasmon band of the nanorods and the excitation line. As a proof of concept, the Au@Ag core-shell nanorods were used to catalyze 4-nitrophenol molecules, and 4-hydroxyazobenzene molecules as the product were confirmed by in situ SERS spectra as well theoretical predictions, showing potential in plasmon driven catalysis and degradation of organic molecules.

Surface Roughening of Pt-Polystyrene Spherical Janus Micromotors for Enhanced Motion Speed.

Spherical Janus micromotors (SJMs) have attracted much attention, and their high-speed motion is highly desired due to their various potential applications. However, the conventional template-deposition method often leads to an active Pt coating with a smooth surface, which is unbeneficial to speed enhancement in terms of catalytic reaction. Here, a facile surface roughening method is presented to fabricate the Pt-polystyrene (PS) SJMs with rough Pt surface (or Ptr-PS SJMs) by plasma-etching the PS colloidal monolayer and then depositing Pt. The Ptr-PS SJMs can exhibit directional motion pushed by the Pt in the various H2O2 solutions, and they show much higher motion speeds than the Pt-PS SJMs with smooth Pt surfaces at the same H2O2 concentration. The Pt-pushed motion is related to the locally asymmetric catalytic reaction of the Pt coating on PS. The speed is also associated with the surface roughness of the Pt coating. The Pt film with a rough surface causes enhanced motion speed due to the improvement of reaction catalytic activity. This work presents a new route to enhancing the motor motion speed, which is of significance in designing micromotors with high-speed motion.

Ag-Nanoparticles@Bacterial Nanocellulose as a 3D Flexible and Robust Surface-Enhanced Raman Scattering Substrate.

We present a well-designed, low-cost, and simple synthetic approach to realizing the hybrid composites of Ag nanoparticle-decorated bacterial nanocellulose (denoted as Ag-NPs@BNC) as a three-dimensional (3D) flexible surface-enhanced Raman scattering (SERS) substrate with ultrahigh SERS sensitivity, excellent signal reproducibility, and stability. The homogeneous Ag-NPs with high density were in situ grown on the networked BNC fibers by the controlled silver mirror reaction and volume shrinkage treatment, which created uniformly distributed SERS "hot spots" in the 3D networked hybrid substrate. Attributed to these unique 3D hot spots, the as-presented Ag-NPs@BNC substrates exhibited ultrahigh sensitivity and good spectral reproducibility. Moreover, the hydrophilic BNC exhibits good permeability and adsorption performances, which could capture the target molecules in the highly active hot spot areas to further improve the SERS sensitivity. As a result, not only dye molecules (rhodamine 6G) but also toxic organic pollutants such as 2-naphthalenethiol and thiram have been detected using the hybrid substrates as SERS substrates, with sensitivities of 1.6 × 10-8 and 3.8 × 10-9 M, respectively. The good linear response of the intensity and the logarithmic concentration revealed promising applications in the rapid and quantitative detection of toxic organic pollutants. Besides, this self-supported Ag-NPs@BNC substrate demonstrated good stability and flexibility for varied detection conditions. Therefore, the 3D networked, flexible, ultrasensitive, and stable Ag-NPs@BNC substrate shows potential as a versatile SERS substrate in the rapid identification of various organic molecules.

HIV-Related Stress Experienced by Newly Diagnosed People Living with HIV in China: A 1-Year Longitudinal Study.

This study explored the HIV-related stressors that people living with HIV (PLWH) commonly experience and express as stressful at the time of diagnosis and 1 year later. The factors associated with stress levels and whether social support would moderate the negative effects of stress on psychological health (depressive and anxiety symptoms) were also investigated. Newly diagnosed PLWH were consecutively recruited in this study. Participants rated their stress with the HIV/AIDS Stress Scale at baseline and 1 year later. Social support, depression, and anxiety were also self-reported at both time points. There were significant decreases in stress levels 1 year after diagnosis. Stressors regarding confidentiality, disclosure, emotional distress, fear of infecting others, and excessive attention to physical functions were the most problematic at baseline and 1-year follow-up. A younger age, married status, not living alone, less income, presence of HIV symptoms, and lack of social support were associated with higher levels of stress. No stress-buffering effect of social support on depressive and anxiety symptoms was found in this study. Interventions to reduce stress among PLWH should take into consideration the following priority stressors: confidentiality, discrimination/stigma, serostatus disclosure, distressing emotions, fear of infecting others, and excessive attention to physical functions. More attention should be paid to PLWH with younger age, not living alone, less income, presence of HIV symptoms, and lack of social support.