Association between alcohol consumption and sleep traits: observational and mendelian randomization studies in the UK biobank.

Previous studies have shown that excessive alcohol consumption is associated with poor sleep. However, the health risks of light-to-moderate alcohol consumption in relation to sleep traits (e.g., insomnia, snoring, sleep duration and chronotype) remain undefined, and their causality is still unclear in the general population. To identify the association between alcohol consumption and multiple sleep traits using an observational and Mendelian randomization (MR) design. Observational analyses and one-sample MR (linear and nonlinear) were performed using clinical and individual-level genetic data from the UK Biobank (UKB). Two-sample MR was assessed using summary data from genome-wide association studies from the UKB and other external consortia. Phenotype analyses were externally validated using data from the National Health and Nutrition Examination Survey (2017-2018). Data analysis was conducted from January 2022 to October 2022. The association between alcohol consumption and six self-reported sleep traits (short sleep duration, long sleep duration, chronotype, snoring, waking up in the morning, and insomnia) were analysed. This study included 383,357 UKB participants (mean [SD] age, 57.0 [8.0] years; 46% male) who consumed a mean (SD) of 9.0 (10.0) standard drinks (one standard drink equivalent to 14 g of alcohol) per week. In the observational analyses, alcohol consumption was significantly associated with all sleep traits. Light-moderate-heavy alcohol consumption was linearly linked to snoring and the evening chronotype but nonlinearly associated with insomnia, sleep duration, and napping. In linear MR analyses, a 1-SD (14 g) increase in genetically predicted alcohol consumption was associated with a 1.14-fold (95% CI, 1.07-1.22) higher risk of snoring (P < 0.001), a 1.28-fold (95% CI, 1.20-1.37) higher risk of evening chronotype (P < 0.001) and a 1.24-fold (95% CI, 1.13-1.36) higher risk of difficulty waking up in the morning (P < 0.001). Nonlinear MR analyses did not reveal significant results after Bonferroni adjustment. The results of the two-sample MR analyses were consistent with those of the one-sample MR analyses, but with a slightly attenuated overall estimate. Our findings suggest that even low levels of alcohol consumption may affect sleep health, particularly by increasing the risk of snoring and evening chronotypes. The negative effects of alcohol consumption on sleep should be made clear to the public in order to promote public health.

Factors associated with euphoria in a large subset of cases using propofol sedation during gastrointestinal endoscopy.

Background: The utilization of Propofol, a widely used intravenous sedative or anesthetic, is characterized by its quick onset, predictable control, and fleeting half-life during both general anesthesia and intensive care unit sedation. Recent evidence, however, has highlighted propofol's propensity to induce euphoria, particularly in patients undergoing painless procedures such as gastrointestinal or gastric endoscopy. Given its widespread use in patients undergoing such procedures, this study aims to investigate the clinical evidence and factors that may influence propofol-induced euphoria in these settings. Methods: The Addiction Research Center Inventory-Chinese Version (ARCI-CV) scale was administered to 360 patients undergoing gastric or gastrointestinal endoscopy using propofol as a sedative. Patient characteristics including past medical history, depression, anxiety, alcohol abuse, and sleep disturbance were recorded through history taking and assessment using various questionnaires prior to the examination. The euphoric and sedative statuses were assessed at 30 min and 1 week post-examination. Results: The experimental results of a survey of 360 patients who underwent gastric or gastrointestinal endoscopy using propofol showed that the mean Morphine-Benzedrine Group (MBG) score before the procedure and after 30 min of the procedure was 4.23 and 8.67, respectively. The mean Pentobarbital-Chlorpromazine-Alcohol Group (PCAG) score before the procedure and after 30 min of the procedure was 3.24 and 6.22, respectively. These results showed that both MBG and PCAG scores increased significantly after the procedure. Certain factors, such as dreaming, propofol dose, duration of anesthesia, and etomidate dose, were all correlated with MBG both at 30 min and 1 week after the examination. In addition, etomidate had an effect of decreasing MBG scores and increasing PCAG scores both at 30 min and 1 week after the examination. Conclusion: Taken together, propofol may elicit euphoria and potentially contribute to propofol addiction. There are several risk factors for the development of propofol addiction, including dreaming, propofol dose, duration of anesthesia, and etomidate dose. These findings suggest that propofol may have a euphoric effect and may have the potential for drug addiction and abuse.

Prevalence and risk factor for long COVID in children and adolescents: A meta-analysis and systematic review.

BACKGROUND: Millions of COVID-19 pediatric survivors are facing the risk of long COVID after recovery from acute COVID-19. The primary objective of this study was to systematically review the available literature and determine the pooled prevalence of, and risk factors for long COVID among the pediatric survivors. METHODS: Studies that assessed the prevalence of, or risk factors associated with long COVID among pediatric COVID-19 survivors were systematically searched in PubMed, Embase, and Cochrane Library up to December 11th, 2022. Random effects model was performed to estimate the pooled prevalence of long COVID among pediatric COVID-19 patients. Subgroup analyses and meta-regression on the estimated prevalence of long COVID were performed by stratification with follow-up duration, mean age, sex ratio, percentage of multisystem inflammatory syndrome, hospitalization rate at baseline, and percentage of severe illness. RESULTS: Based on 40 studies with 12,424 individuals, the pooled prevalence of any long COVID was 23.36 % ([95 % CI 15.27-32.53]). The generalized symptom (19.57 %, [95 % CI 9.85-31.52]) was reported most commonly, followed by respiratory (14.76 %, [95 % CI 7.22-24.27]), neurologic (13.51 %, [95 % CI 6.52-22.40]), and psychiatric (12.30 %, [95% CI 5.38-21.37]). Dyspnea (22.75 %, [95% CI 9.38-39.54]), fatigue (20.22 %, [95% CI 9.19-34.09]), and headache (15.88 %, [95 % CI 6.85-27.57]) were most widely reported specific symptoms. The prevalence of any symptom during 3-6, 6-12, and> 12 months were 26.41 % ([95 % CI 14.33-40.59]), 20.64 % ([95 % CI 17.06-24.46]), and 14.89 % ([95 % CI 6.09-26.51]), respectively. Individuals with aged over ten years, multisystem inflammatory syndrome, or had severe clinical symptoms exhibited higher prevalence of long COVID in multi-systems. Factors such as older age, female, poor physical or mental health, or had severe infection or more symptoms were more likely to have long COVID in pediatric survivors. CONCLUSIONS: Nearly one quarter of pediatric survivors suffered multisystem long COVID, even at 1 year after infection. Ongoing monitoring, comprehensive prevention and intervention is warranted for pediatric survivors, especially for individuals with high risk factors.

Efficacy and tolerability of pharmacological treatments for insomnia in adults: A systematic review and network meta-analysis.

Insomnia is one of the most common and burdensome disorders in adults. We compared and ranked insomnia medication on the basis of their efficacy and tolerability. We performed a systematic review and network meta-analysis of placebo-controlled or head-to-head randomized controlled trials for primary insomnia in adults comparing 20 drugs. We searched eight databases and seven trial registers from inception to March 1st, 2022. Primary outcomes included sleep latency (SL), awake time after sleep onset (WASO) and discontinuation for adverse events (AED), and secondary outcomes included total sleep time (TST), sleep efficiency (SE), sleep quality (SQ) and adverse events (ADE). Pooled standardized mean differences or odds ratios with 95% credible intervals were estimated using pairwise and network meta-analysis with random-effects. Differences among trial findings were explored in subgroup and sensitivity analyses. Confidence in evidence was assessed using GRADE. The PROSPERO registered number is CRD42020182144. We identified 22,538 records and included 69 studies (17,319 patients). Orexin receptor antagonists (ORAs) are more efficacious than benzodiazepine-like drugs (Z-drugs) and placebo for WASO and SE, and better than melatonin receptor agonists (MRAs) for SL, WASO and SE. ORAs ranked the best in SL (SUCRA value: 0.84), WASO (0.93), TST (0.86) and SE (0.96). Lemborexant and daridorexant (two ORAs) showed greater efficacy than placebo for SL, WASO, and TST, with good tolerability. Z-drugs were more efficacious than placebo for SL, WASO, TST and SE, but with higher risk to safety. Zaleplon and eszopiclone had better efficacy than placebo for TST and SQ respectively. MRAs may also be efficacious for sleep-onset insomnia with good safety. However, the long-term adverse effects of all medications are unclear. Insomnia medications differ in their efficacy and tolerability. ORAs have superior efficacy and tolerability. These findings should aid clinicians in matching risk/benefits of drugs available in their countries to insomnia symptoms.

The effect of a methadone-initiated memory reconsolidation updating procedure in opioid use disorder: A translational study.

BACKGROUND: Opioid use disorder (OUD) is a chronic relapsing psychiatric disorder. An unconditioned stimulus (US)-triggers a memory reconsolidation updating procedure (MRUP) that has been developed and demonstrated its effectiveness in decreasing relapse to cocaine and heroin in preclinical models. However, utilizations of abused drugs as the US to initiate MRUP can be problematic. We therefore designed a translational rat study and human study to evaluate the efficacy of a novel methadone-initiated MRUP. METHODS: In the rodent study, male rats underwent heroin self-administration training for 10 consecutive days, and were randomly assigned to receive saline or methadone at 10 min, 1 h or 6 h before extinction training after 28-day withdrawal. The primary outcome was operant heroin seeking after reinstatement. In the human experimental study, male OUD patients were randomly assigned to get MRUP at 10 min or 6 h after methadone or methadone alone. The primary outcomes included experimental cue-induced heroin craving change, sustained abstinence and retention in the study at post intervention and the 5 monthly follow-up assessments. The secondary outcomes were changes in physiological responses including experimental cue-induced blood pressure and heart rate. FINDINGS: Methadone exposure but not saline exposure at 10 min or 1 h before extinction decreased heroin-induced reinstatement of heroin seeking after 28-day of withdrawal in rats (F (8,80) = 8.26, p < 0.001). In the human study, when the MRUP was performed 10 min, but not 6 h after methadone dosing, the MRUP promoted sustained abstinence from heroin throughout 5 monthly follow-up assessments compared to giving methadone alone without MRUP (Hazard Ratio [95%CI] of 0.43 [0.22, 0.83], p = 0.01). The MRUP at 10 min, but not at 6 h after dosing also decreased experimental cue-induced heroin craving and blood pressure increases during the 6-month study duration (group × months × cue types, F (12, 63·3) = 2.41, p = 0.01). INTERPRETATION: The approach of MRUP within about 1 to 6 h after a methadone dose potently improved several key outcomes of OUD patients during methadone maintenance treatment, and could be a potentially novel treatment to prevent opioid relapse. FUNDING: National Natural Science Foundation of China (NO. U1802283, 81761128036, 82001400, 82001404 and 31671143) and Chinese National Programs for Brain Science and Brain-like Intelligence Technology (NO. 2021ZD0200800).

Workforce situation of the Chinese mental health care system: results from a cross-sectional study.

BACKGROUND: High-quality mental health services can improve outcomes for people with mental health problems and abate the burden of mental disorders. We sought to identify the challenges the country's mental health system currently faces and the human resource situation related to psychological services and to provide recommendations on how the mental health workforce situation could be addressed in China. METHODS: This study used a cross-sectional survey design. A web-based questionnaire approach and a convenience sampling method were adopted. It was carried out from September 2020 to January 2021 in China, and we finally included 3824 participants in the analysis. Descriptive statistical analysis of the characteristics of the study sample was performed. The risk factors for competence in psychological counseling/psychotherapy were assessed using multiple linear regression analysis. RESULTS: Workforce related to psychotherapy is scarce in China, especially in Western China and community mental health sectors. Psychiatrists (39.1%) and nurses (38.9%) were the main service providers of psychotherapy in psychiatric hospitals, and clinical psychologists (6.9%) and counsellors (5.0%) were seriously scarce in mental health care sectors. A total of 74.2% of respondents had no systematic psychological training, and 68.4 and 69.2% of them had no self-experience and professional supervision, respectively. Compared with clinical psychologists and counselors, psychiatrists and nurses had less training. Systematic psychological training (ß = - 0.88), self-experience (ß = - 0.59) and professional supervision (ß = - 1.26) significantly influenced psychotherapy capacity (P<0.001). CONCLUSIONS: Sustained effort will be required to provide a high-quality, equitably distributed psychotherapy workforce in China, despite challenges for community mental health sectors and western China being likely to continue for some time. Because mental illness is implicated in so many burgeoning social ills, addressing this shortfall could have wide-ranging benefits.

Mental health services for infectious disease outbreaks including COVID-19: a rapid systematic review.

The upsurge in the number of people affected by the COVID-19 is likely to lead to increased rates of emotional trauma and mental illnesses. This article systematically reviewed the available data on the benefits of interventions to reduce adverse mental health sequelae of infectious disease outbreaks, and to offer guidance for mental health service responses to infectious disease pandemic. PubMed, Web of Science, Embase, PsycINFO, WHO Global Research Database on infectious disease, and the preprint server medRxiv were searched. Of 4278 reports identified, 32 were included in this review. Most articles of psychological interventions were implemented to address the impact of COVID-19 pandemic, followed by Ebola, SARS, and MERS for multiple vulnerable populations. Increasing mental health literacy of the public is vital to prevent the mental health crisis under the COVID-19 pandemic. Group-based cognitive behavioral therapy, psychological first aid, community-based psychosocial arts program, and other culturally adapted interventions were reported as being effective against the mental health impacts of COVID-19, Ebola, and SARS. Culturally-adapted, cost-effective, and accessible strategies integrated into the public health emergency response and established medical systems at the local and national levels are likely to be an effective option to enhance mental health response capacity for the current and for future infectious disease outbreaks. Tele-mental healthcare services were key central components of stepped care for both infectious disease outbreak management and routine support; however, the usefulness and limitations of remote health delivery should also be recognized.

Association between ambient particulate matter and hospitalization for anxiety in China: A multicity case-crossover study.

AIMS: Evidence concerning the impact of ambient particulate matter (PM) on mental health is just emerging and inconsistent. Air pollution with high PM levels has been frequently reported in China, however, no Chinese study has determined the association between PM exposures and anxiety hospitalizations. We examined the potential association between PM concentrations and anxiety admissions in 26 Chinese cities from January 2014 to December 2015. METHODS: A time-stratified case-crossover design was employed in the study. Anxiety hospitalizations were identified according to ICD-10 from the electronic hospitalization summary reports system in China. Conditional logistic regression was applied to estimate the relation between PM levels and anxiety admissions, stratified by age and sex. RESULTS: Positive associations between PM2.5/PM10 and admitted anxiety cases were observed. PM2.5 had the largest effect estimate at lag 5 days, with a per 10 µg/m3 increase corresponding to a 0.63% (95% CI, 0.26-1.00) increase in anxiety admissions. PM10's largest effect estimate was observed at lag 3 days, increasing 0.37% (95% CI, 0.12-0.62) anxiety admissions per 10 µg/m3. Females were more sensitive to PM2.5/PM10 concentrations than males, however, the effect modification by age was not significant. A marginally significant distinction in anxiety hospitalizations was found in patients with and without CVDs when they were exposed to PM2.5. CONCLUSIONS: Our findings indicate that short-term exposure to increased concentrations of PM2.5/PM10 exacerbates risks of anxiety hospitalizations in 26 Chinese cities. We observed effect modification by sex, with significantly stronger associations in female patients. This study offers the promise that reducing PM air pollution could probably reduce the huge disease burden from anxiety disorders.

Online Survey on Accessing Psychological Knowledge and Interventions During the COVID-19 Pandemic - China, 2020.

What is already known on this topic? The public was at elevated risk of mental health illnesses during the coronavirus disease 2019 (COVID-19) pandemic, so accessibility to psychological knowledge and interventions is vital to promptly respond to mental health crises. What is added by this report? During the pandemic period, 40,724 (71.9%) participants reportedly had access to psychological knowledge, and 36,546 (64.5%) participants had accessed information on psychological interventions. Participants who were male, unmarried, living alone, divorced or widowed, or infected with COVID-19 were less likely to access psychological knowledge and intervention. What are the implications for public health practice? Governments should pay more attention to formulate policies, popularize psychological education, and provide mental health services online or in the community.

Ambient fine particulate matter is associated with increased emergency ambulance dispatches for psychiatric emergencies.

AIMS: As a top ambient pollutant in urban area, fine particulate matter (PM2.5) has been associated with the occurrence and deterioration of many medical conditions, while limited studies have observed the association with psychiatric conditions. This study aimed to investigate the association between short-term PM2.5 exposure and psychiatric emergency events, and further explored the variation by age, sex and seasonal patterns, which have been suggested to be associated with both psychiatric risk and pollutant toxicity. METHODS: We used time-series analysis to investigate the association between short-term exposure of PM2.5 and emergency ambulance dispatches for psychiatric emergencies (EPE) (n = 158634) in Beijing, one of the top polluted cities in China during the study period between 2008 and 2014. Stratified analyses were conducted to examine the effects of age, sex and seasonal pattern. RESULTS: Every 10 µg/m3 increase of the PM2.5 concentration was associated with a 0.12% increase of the same-day overall EPE (95% CI: 0.03-0.22%, p = 0.013) and a 0.12% increase of the suicide-related EPE at lag 2 (95%CI: 0.01-0.24%, p = 0.041). The associations remained when adjusted for sunlight duration. An age effect was observed where children (age <18) showed a higher risk of suicide-related EPE after PM2.5 exposure compared to adults (18 ≤ age≤64). We did not observe evidence of effect modification by sex and season based on the results of stratified analysis. CONCLUSIONS: We found a positive association between acute PM2.5 exposure and increased psychiatric emergency presentations indicated by emergency ambulance dispatches data. Children were more vulnerable and might develop psychiatric problems including those leading to suicide. Public awareness of the health risks of PM2.5 is important to strengthen current efforts to reduce emissions.

Behavioral interventions to eliminate fear responses.

Fear memory underlies anxiety-related disorders, including posttraumatic stress disorder (PTSD). PTSD is a fear-based disorder, characterized by difficulties in extinguishing the learned fear response and maintaining extinction. Currently, the first-line treatment for PTSD is exposure therapy, which forms an extinction memory to compete with the original fear memory. However, the extinguished fear often returns under numerous circumstances, suggesting that novel methods are needed to eliminate fear memory or facilitate extinction memory. This review discusses research that targeted extinction and reconsolidation to manipulate fear memory. Recent studies indicate that sleep is an active state that can regulate memory processes. We also discuss the influence of sleep on fear memory. For each manipulation, we briefly summarize the neural mechanisms that have been identified in human studies. Finally, we highlight potential limitations and future directions in the field to better translate existing interventions to clinical settings.

Enhanced temporal variability of amygdala-frontal functional connectivity in patients with schizophrenia.

Background: The "dysconnectivity hypothesis" was proposed 20 years ago. It characterized schizophrenia as a disorder with dysfunctional connectivity across a large range of distributed brain areas. Resting-state functional magnetic resonance imaging (rsfMRI) data have supported this theory. Previous studies revealed that the amygdala might be responsible for the emotion regulation-related symptoms of schizophrenia. However, conventional methods oversimplified brain activities by assuming that it remained static throughout the entire scan duration, which may explain why inconsistent results have been reported for the same brain region. Methods: An emerging technique is sliding time window analysis, which is used to describe functional connectivity based on the temporal variability of regions of interest (e.g., amygdala) in patients with schizophrenia. Conventional analysis of the static functional connectivity between the amygdala and whole brain was also conducted. Results: Static functional connectivity between the amygdala and orbitofrontal region was impaired in patients with schizophrenia. The variability of connectivity between the amygdala and medial prefrontal cortex was enhanced (i.e., greater dynamics) in patients with schizophrenia. A negative relationship was found between the variability of connectivity and information processing efficiency. A positive correlation was found between the variability of connectivity and symptom severity. Conclusion: The findings suggest that schizophrenia was related to abnormal patterns of fluctuating communication among brain areas that are involved in emotion regulations. Unveiling the temporal properties of functional connectivity could disentangle the inconsistent results of previous functional connectivity studies.

Cooccurrence and bidirectional prediction of sleep disturbances and depression in older adults: Meta-analysis and systematic review.

The present study pooled the prevalence of sleep disturbances and depression in community-dwelling older adults (mean age≥60years) and quantified the strength of evidence of the relationship between these two problems. From 23 cross-sectional studies and five sets of baseline data, a high pooled prevalence of sleep disturbances (30.5%), depressive symptoms (18.1%) and coexisting disorders (10.6%) were found. In the 23 cohort studies, self-reported sleep disturbances increased the risk of the onset of depression (relative risk [RR]=1.92). Persistent sleep disturbances increased the risk of the development (RR=3.90), recurrence (RR=7.70), and worsening (RR=1.46) of depression in older adults. Little support was found for a predictive role for objective sleep characteristics in the development of depression. Older adults with depression had a higher risk of developing (RR=1.72) and worsening (RR=1.73) symptoms of sleep disturbances. This review emphasizes the importance of timely interventions in incipient sleep disturbances and depression among older adults, preventing the development of more serious comorbidities.

Preparation of Fe2O3-Clorprenaline/Tetraphenylborate Nanospheres and Their Application as Ion Selective Electrode for Determination of Clorprenaline in Pork.

A novel modified ion selective electrode based on Fe2O3-clorprenaline/tetraphenylborate nanospheres (Fe2O3-CLPT NSs) as electroactive materials for the determination of clorprenaline hydrochloride (CLP) is described. The α-Fe2O3 nanoparticles (NPs) were prepared by hydrothermal synthesis, then self-assembled on CLP/tetraphenylborate (TPB) to form Fe2O3-CLPT NSs, which were used as a potentiometric electrode for analyte determination innovatively. The Fe2O3-CLPT NSs modified electrode exhibited a wider concentration range from 1.0 × 10(-7) to 1.0 × 10(-1) mol/L and a lower detection limit of 3.7 × 10(-8) mol/L compared with unmodified electrodes. The selectivity of the modified electrode was evaluated by fixed interference method. The good performance of the modified electrode such as wide pH range (2.4-6.7), fast response time (15 s), and adequate lifetime (14 weeks) indicate the utility of the modified electrode for evaluation of CLP content in various real samples. Finally, the modified electrode was successfully employed to detect CLP in pork samples with satisfactory results. These results demonstrated the Fe2O3-CLPT NSs modified electrode to be a functional and convenient method to the field of potentiometry determination of CLP in real samples.

Diurnal neurobiological alterations after exposure to clozapine in first-episode schizophrenia patients.

BACKGROUND: Irregular circadian rhythm and some of its most characteristic symptoms are frequently observed in patients with schizophrenia. However, changes in the expression of clock genes or neuropeptides that are related to the regulation of circadian rhythm may influence the susceptibility to recurrence after antipsychotic treatment in schizophrenia, but this possibility has not been investigated. METHODS: Blood samples were collected from 15 healthy male controls and 13 male schizophrenia patients at 4h intervals for 24h before and after treatment with clozapine for 8 weeks. The outcome measures included the relative expression of clock gene mRNA PERIOD1 (PER1), PERIOD2 (PER2), PERIOD3 (PER3) and the levels of plasma cortisol, orexin, and insulin. RESULTS: Compared with healthy controls, schizophrenia patients presented disruptions in diurnal rhythms of the expression of PER1, PER3, and NPAS2 and the release of orexin, accompanied by a delayed phase in the expression of PER2, decreases in PER3 and NPAS2 expression, and an increase in cortisol levels at baseline. Several of these disruptions (i.e., in PER1 and PER3 expression) persisted after 8 weeks of clozapine treatment, similar to the decreases in the 24-h expression of PER3 and NPAS2. Clozapine treatment for 8 weeks significantly decreased the 24-h levels of PER2 and increased the 24-h levels of insulin. CONCLUSION: These persistent neurobiological changes that occur after 8 weeks of clozapine treatment may contribute to the vulnerability to recurrence and efficacy of long-term maintenance treatment in schizophrenia.

Preparation of ractopamine-tetraphenylborate complexed nanoparticles used as sensors to rapidly determine ractopamine residues in pork.

In this work, we reported a simple, fast, and sensitive determination of ractopamine (RAC) residues in pork by using novel ractopamine-tetraphenylborate complexed nanoparticles (RT NPs) as sensors. The prepared RT NPs exhibited a fast response time of 10 s, a wide linear range from 0.1 to 1.0 × 10(-7) mol/L, and a very low detection limit of 7.4 × 10(-8) mol/L. The prepared sensor also presents a high selectivity for ractopamine under different pH conditions ranged from 2.85 to 7.18. These results reveal that the fabricated RT NPs can be used as efficient electrochemical sensors to determine ractopamine in animal productions.

Preparation TiO2 core-shell nanospheres and application as efficiency drug detection sensor.

In this paper, we report the facile preparation of monodisperse titanium dioxide-diltiazem/tetrachlorobismuth core-shell nanospheres (TiO2@DTMBi), in which, diltiazem (DTM)/tetrachlorobismuth (BiCl4) complexes were employed as electroactive materials. The morphology, size, formation, and structure of the obtained TiO2@DTMBi spheres were investigated by transmission electron microscopy, scanning electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and X-ray diffraction. The optimal condition of obtained monodisperse 40-nm TiO2@DTMBi spheres was researched. The results of using TiO2@DTMBi nanospheres as proposed drug sensor indicate a wide linear range (10(-7) to 10(-1) M) and a very low detection limit of 0.20 µg/mL.

One-pot synthesis of graphene-chitosan nanocomposite modified carbon paste electrode for selective determination of dopamine

Background A simple, rapid, low-cost and environmentally friendly method was developed to determine dopamine (DA) in the presence of ascorbic (AA) and uric acid (UA) based on a novel technique to prepare a graphene-chitosan (GR-CS) nanocomposite and modify it on the surface of carbon paste electrode (CPE). For our design, CS acts as a media to disperse and stabilize GR, and then GR plays a key role to selective and sensitive determination of DA. Results Under physiological conditions, the linear range for dopamine was determined from 1 × 10- 4 to 2 × 10- 7 mol/L with a good correlation coefficient of 0.9961 in the presence of 1000-fold interference of AA and UA. The detection limit was estimated to be 9.82 × 10- 8 mol/L (S/N = 3). In order to study the stability and reproducibility, GR/CS/CPE underwent successive measurements in 10 times and then tested once a d for 30 d. The result exhibited 98.25% and 91.62% activities compared with the original peak current after 10-time measurements and 30-d storage. Conclusion The GR/CS/CPE has wide linear concentration range, low detection limit, and good reproducibility and stability, which suggests that our investigations provide a promising alternative for clinic DA determination.