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In this study, we have developed a novel, hypersensitive, and ultraselective electrochemical sensor containing thermally annealed gold-silver alloy nanoporous matrices (TA-Au-Ag-ANpM) integrated with f-MWCNTs-CPE and poly(l-serine) nanocomposites for the simultaneous detection of sulfathiazole (SFT) and sulfamethoxazole (SFM) residues in honey, beef, and egg samples. TA-Au-Ag-ANpM/f-MWCNTs-CPE/poly(l-serine) was characterized using an extensive array of analytical (UV-Vis, FT-IR, XRD, SEM, and EDX), and electrochemical (EIS, CV and SWV) techniques. It exhibited outstanding performance over a wide linear range, from 4.0 pM to 490 μM for SFT and 4.0 pM to 520 μM for SFM, with picomolar detection and quantification limits (0.53 pM and 1.75 pM for SFT, 0.41 pM and 1.35 pM for SFM, respectively). The sensor demonstrated exceptional repeatability, reproducibility, and anti-interference capability, with percentage recovery of 95.6-102.4% in food samples and RSD below 5%. Therefore, the developed sensor is an ideal tool to address the current antibiotic residue crisis in food sources., Competing Interests: Declaration of competing interest We want to affirm that there are no recognized conflicts of interest associated with this publication, and this study has not received dedicated funding from any public, commercial, or non-profit sector funding entity. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Background: The widespread use and abuse of antibiotics has resulted in the pollution of water sources with antibiotic residues, posing a threat to human health, the environment, and the economy. Therefore, a highly sensitive and selective method is required for their detection in water samples. Herein, advanced ultrasensitive electrochemical sensor platform was developed by integrating gold-silver alloy nanocoral clusters (Au-Ag-ANCCs) with functionalized multi-walled carbon nanotube-carbon paste electrode (f-MWCNT-CPE) and choline chloride (ChCl) nanocomposites for simultaneously determining the residues of antimicrobial drugs, rifampicin (RAMP) and norfloxacin (NFX), in water samples., Results: The developed sensor (Au-Ag-ANCCs/f-MWCNTs-CPE/ChCl) was extensively characterized using several analytical (UV-Vis, FT-IR, XRD, SEM, and EDX) and electrochemical (EIS, CV, and SWV) techniques. It exhibited outstanding performance in a wide linear range, from 14 pM to 115 μM for RAMP, and from 0.9 nM to 200 μM for NFX, with a limit of detection (LOD, 3σ/m, S/N = 3, n = 5) and a limit of quantification (LOQ, 10σ/m, S/N = 3, n = 5) values of 2.7 pM and 8.85 pM for RAMP, and 0.14 nM and 0.47 nM for NFX, respectively. The sensor also exhibited exceptional reproducibility, stability, and resistance to interference., Significance: The developed sensor was effectively utilized to determine RAMP and NFX residues in hospital wastewater, river, and tap water samples, yielding recoveries within the range of 96.8-103 % and relative standard deviations below 5 %. Generally, the proposed sensor demonstrated remarkable performance in detecting the target analytes, making it an ideal tool and the first of its kind for addressing global antibiotic residue pollutants in water sources., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The widespread use and misuse of antibiotics in pharmaceuticals and animal farming has resulted in their accumulation in food sources and the environment, posing significant threats to human health, the environment, and the global economy. In this study, we have developed a hypersensitive, and ultra-selective electrochemical sensor, the first of its kind, by integrating a thermally annealed gold-silver alloy nanoporous matrix (TA-Au-Ag-ANpM) with reduced graphene oxide (r-GO) and poly(glycine) at the surface of a glassy carbon electrode (GCE). This sensor aims to detect life-threatening metronidazole (MTZ) residues in food samples. TA-Au-Ag-ANpM/r-GO/poly(glycine)/GCE was thoroughly characterized using a range of analytical techniques, including UV-Vis, FT-IR, XRD, SEM, and EDX. Furthermore, its electrochemical properties were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The sensor exhibited outstanding performance, with a broad linear range of 2.0 pM-410 μM. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.0312 pM and 0.104 pM, respectively. The TA-Au-Ag-ANpM/r-GO/poly(glycine)/GCE exhibited exceptional reproducibility, repeatability, stability, and resistance to interferences. Moreover, the sensor demonstrated outstanding performance in detecting MTZ residues in milk powder, pork, and chicken meat samples, achieving very good recoveries (96.9%-101.4%) with a relative standard deviation (RSD) below 5%. This performance highlights the potential for practical applications in food safety and quality monitoring. Therefore, the developed sensor contributes to the advancement of electrochemical sensing technology and its application in ensuring food safety and integrity by combating antibiotic residues., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Nurses turnover intention, representing the extent to which nurses express a desire to leave their current positions, is a critical global public health challenge. This issue significantly affects the healthcare workforce, contributing to disruptions in healthcare delivery and organizational stability. In Ethiopia, a country facing its own unique set of healthcare challenges, understanding and mitigating nursing turnover are of paramount importance. Hence, the objectives of this systematic review and meta-analysis were to determine the pooled proportion ofturnover intention among nurses and to identify factors associated to it in Ethiopia., Methods: A comprehensive search carried out for studies with full document and written in English language through an electronic web-based search strategy from databases including PubMed, CINAHL, Cochrane Library, Embase, Google Scholar and Ethiopian University Repository online. Checklist from the Joanna Briggs Institute (JBI) was used to assess the studies' quality. STATA version 17 software was used for statistical analyses. Meta-analysis was done using a random-effects method. Heterogeneity between the primary studies was assessed by Cochran Q and I-square tests. Subgroup and sensitivity analyses were carried out to clarify the source of heterogeneity., Result: This systematic review and meta-analysis incorporated 8 articles, involving 3033 nurses in the analysis. The pooled proportion of turnover intention among nurses in Ethiopia was 53.35% (95% CI (41.64, 65.05%)), with significant heterogeneity between studies (I 2  = 97.9, P = 0.001). Significant association of turnover intention among nurses was found with autonomous decision-making (OR: 0.28, CI: 0.14, 0.70) and promotion/development (OR: 0.67, C.I: 0.46, 0.89)., Conclusion and Recommendation: Our meta-analysis on turnover intention among Ethiopian nurses highlights a significant challenge, with a pooled proportion of 53.35%. Regional variations, such as the highest turnover in Addis Ababa and the lowest in Sidama, underscore the need for tailored interventions. The findings reveal a strong link between turnover intention and factors like autonomous decision-making and promotion/development. Recommendations for stakeholders and concerned bodies involve formulating targeted retention strategies, addressing regional variations, collaborating for nurse welfare advocacy, prioritizing career advancement, reviewing policies for nurse retention improvement., (© 2024. The Author(s).)

Anthracyclines are effective chemotherapeutic agents widely used to treat various cancers, but their use is limited by the risk of cardiotoxicity and heart failure. While strategies like dose reduction have been explored, there are no well-established therapies to mitigate this risk. Emerging evidence suggests sodium-glucose cotransporter 2 inhibitors (SGLT2i) may have cardioprotective effects, providing a rationale for investigating their potential utility in anthracycline-treated patients. We conducted a systematic review and meta-analysis to synthesize available evidence on the efficacy of SGLT2i in reducing heart failure incidence and mortality in patients undergoing anthracycline-based cancer therapy. Relevant studies were identified through comprehensive database searches and screened based on predefined criteria. Data extraction and quality assessment were performed independently by two reviewers. Four observational studies, encompassing 5,590 patients, were included. The pooled analysis showed a higher but non-significant risk of developing heart failure in the non-SGLT2i group compared to the SGLT2i group (RR = 0.67, 95% CI: 0.40-1.41). The risk of all-cause mortality was significantly lower in patients receiving SGLT2i (RR = 0.55, 95% CI: 0.39-0.77). This meta-analysis suggests SGLT2i are associated with a lower risk of mortality and heart failure incidence in anthracycline-treated patients, although larger studies are needed to confirm these findings. The mechanisms underlying these potential benefits require further elucidation. Despite limitations, this analysis highlights the promising role of SGLT2i as a cardioprotective strategy in this high-risk population., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Tabowei et al.)

Background: Depression during pregnancy is a significant health concern that can lead to a variety of short and long-term complications for mothers. Unfortunately, there is a lack of information available on the prevalence and predictors of prenatal depression in rural eastern Ethiopia. This study assessed prenatal depression and associated factors among pregnant women attending public health facilities in the Babile district, Eastern Ethiopia., Method: An institution-based cross-sectional study was conducted among 329 pregnant women attending Babile District Public Health Facilities from November 1 to December 30, 2021. Bivariable and multivariable logistic regression were used to identify factors associated with prenatal depression. The adjusted odds ratio (AOR) with a 95% confidence interval was used to report the association, and the significance was declared at a p-value < 0.05., Results: The prevalence of prenatal depression was 33.1% (95% CI = 28.0%, 38.2%). A lower income (AOR = 3.85, 95% CI = 2.08, 7.13), contraceptive use (AOR = 0.53, 95% CI = 0.28, 0.98), unintended pregnancy (AOR = 2.24, 95% CI = 1.27, 3.98), history of depression (AOR = 5.09, 95% CI = 2.77, 9.35), poor social support (AOR = 5.08, 95% CI = 2.15, 11.99), and dissatisfied marriage (AOR = 2.37, 95% CI = 1.30, 4.33) were the factors associated with increased prenatal depression among pregnant women., Conclusions: One in every three pregnant women in rural eastern Ethiopia had prenatal depression. Monthly income, contraceptive use, pregnancy intention, history of depression, social support, and marriage satisfaction status were the determinants of prenatal depression. Preventing unintended pregnancies by encouraging women to utilize modern contraceptive methods is essential for mitigating and controlling the risks and burdens of prenatal depression and its negative consequences., (© 2024. The Author(s).)

The aim of this meta-analysis was to determine the effect of pulmonary hypertension (PH) on survival in patients undergoing transcatheter aortic valve replacement (TAVR). The present study was conducted according to the guidelines of Preferred Reporting of Systematic Review and Meta-Analysis (PRISMA). We conducted a comprehensive search of electronic databases including PubMed/MEDLINE, Embase, Cochrane Library, and Web of Science from January 1, 2015, to March 10, 2024. Outcomes assessed in this meta-analysis included early and late all-cause mortality and cardiovascular mortality. Total 15 studies were integrated into the pooled analysis to assess the impact of PH on outcomes among patients undergoing TAVR, comprising a total sample size of 35,732 individuals. The pooled prevalence of PH stood at 52.57% (n=18,767). Predominantly, the studies were conducted in the United States (n=6), followed by Germany (n=3), with one study each from Japan, Italy, Switzerland, Brazil, Poland, and Australia. Pooled analysis showed that risk of short-term mortality was greater in patients with PH compared to patients without PH (risk ratio (RR): 1.46, 95% CI: 1.19 to 1.80). Risk of long-term mortality was greater in patients with PH (RR: 1.42, 95% CI: 1.29 to 1.55). Risk of cardiovascular mortality was also greater in patients with PH compared to patients without PH (RR: 1.66, 95% CI: 1.36 to 2.02). We advocate for further research to address gaps in understanding different types of PH and their impacts on mortality and cardiovascular outcomes., Competing Interests: Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Khalil et al.)

The objective of this network meta-analysis was to assess the efficacy and safety of apixaban, dabigatran, rivaroxaban, and edoxaban in patients diagnosed with atrial fibrillation and valvular heart disease. A comprehensive search was conducted across various electronic databases, including PubMed, Embase, and Web of Science, from inception to February 15, 2024. The search strategy utilized a combination of medical subject headings (MeSH) terms and relevant keywords related to valvular heart disease, atrial fibrillation, anticoagulant therapy, and study design, such as randomized controlled trials and observational studies. The outcomes evaluated in this analysis comprised the incidence of stroke or systemic embolism (SE), as well as the occurrences of major bleeding events. A total of 10 studies were incorporated into this meta-analysis, encompassing 40,662 participants. Of these, 12,385 received apixaban, 2,829 received dabigatran, 13,662 received rivaroxaban, 2,582 received edoxaban, and 9,202 received warfarin. The duration of follow-up in the included studies ranged from 3 to 54 months. Among the four direct oral anticoagulants (DOACs) studied, apixaban demonstrated a significant reduction in the risk of stroke or SE when compared to other DOACs and warfarin, highlighting its efficacy in patients with atrial fibrillation and valvular heart disease. Additionally, apixaban exhibited a lower risk of major bleeding events, further emphasizing its favorable safety profile compared to the other agents assessed. In conclusion, our findings suggest that apixaban may be more effective and safer than other DOACs and warfarin in this patient population. However, additional studies are warranted to compare the various DOACs in this cohort to identify the optimal treatment strategy for preventing adverse outcomes., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Huma et al.)

This study aimed to assess the concentrations of major and trace metals (Na, Ca, Fe, Zn, Ni, Mn, Cu, Cd, and Pb) in date palm fruit samples collected from diverse regions, including Afar (Ethiopia), Iraq, and Saudi Arabia, utilizing flame atomic absorption spectrometry (FAAS). The wet acid digestion method was employed for sample treatment, with optimization of the key parameters such as reagent volume ratio, oven temperature, and digestion time for analytical applications. Under the optimized parameters, average metal concentrations in date palm fruit samples ranged from 205-299, 134-320, 38.8-115, 25.1-42.2, 9.27-27.9, 7.11-16.3, and 0.002-1.15 mg/kg for Ca, Na, Fe, Ni, Zn, Mn, and Cu, respectively. Cd and Pb levels were below detection limits within the linear range. Generally, date palm samples exhibited higher Ca and Na contents and lower concentrations of Cu and Mn than other metals. Pearson correlation analysis revealed very strong positive correlations between Fe and Na, Na and Zn, Na and Mn, Ca and Zn, Fe and Ni, Fe and Mn, and Mn and Ni. Strong negative correlations were observed for Ni and Na, Fe and Cu, and Cu and Ni. Weak correlations were noted among Na and Cu, Ca and Fe, Ca and Ni, Ca and Mn, Ca and Cu, Fe and Zn, Ni and Zn, Zn and Mn, and Zn and Cu. A recovery study using the spiking method demonstrated acceptable percentage recoveries ranging from 91.6% to 97.8%. Health risk assessment, including chronic daily intake (CDI), hazard quotient (HQ), total exposure hazard index (HI), and carcinogenic risk (CR), indicated CDI, HQ, and HI values below 1.0, except for the HI value for Ni. This suggests that the metals pose no probable public health risk, with the absence of Cd and Pb in date palm samples affirming no carcinogenic threats associated with their consumption., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2024 Feven Tamirat et al.)

In this study, for the first time, the levels of thirteen micro- and macromineral nutrients in the leaves, seeds, and supportive soil of Moringa stenopetala ( M. stenopetala ) were simultaneously determined using microwave plasma atomic emission spectroscopy (MP-AES). The samples were collected during the arid season, in 2019 from the three main M. stenopetala growing areas in southern Ethiopia (Chano Mile Kebele, Nechisar Kebele, and Konso Special Woreda). A novel digestion method for leaf and seed samples was developed using an optimized acid mixture (2.5 : 0.75 : 0.5 of HNO 3 , HClO 4 , and H 2 O 2 ) at 240°C for 2 hrs and 30 min, resulting in clear and colorless solutions. The method makes the digestion process more efficient by minimizing the reagent volume, reducing digestion temperature and time, and simplifying the overall procedure. The efficiency of the optimized procedure was validated by spiking experiments, and the percentage recovery ranged between 94 and 110%. Under optimized experimental conditions, higher concentrations of essential minerals (K, Na, Ca, and Mg) were observed in the plant leaf and seed samples from the three areas. In addition, significant amounts of trace elements (Fe, Mn, Zn, and Cu) were also found. Importantly, no traces of the toxic elements (Cd and Pb) were detected in any of the analyzed samples, suggesting that the leaves and seeds of M. stenopetala are valuable sources of both micro- and macromineral nutrients and are safe from toxic metals. From a dietary perspective, the seed contains almost comparable concentrations of minerals as the leaves. As a result, the seeds of M. stenopetala can serve as an alternative source of minerals and play a role in overcoming the current global food crisis, particularly in the dry season. Analysis of variance at a 95% confidence level revealed significant differences in the levels of all mineral nutrients between the three sample means except K, Ca, Co, and Cu. Generally, the developed method includes an innovative digestion procedure that minimizes reagent consumption, operates at lower temperatures, and requires shorter digestion times, thereby optimizing resource utilization and maintaining analytical accuracy. Notably, the absence of toxic elements in the MP-AES procedure highlights the safety and reliability of M. stenopetala leaves and seeds as valuable, contamination-free sources of essential nutrients., Competing Interests: The authors declare that they have no conflicts of interest or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Ashenafi Shemnsa et al.)

In this study, a new carbon paste electrode modified with a laboratory-synthesized ligand, N 1 -hydroxy-N 1 ,N 2 -diphenylbenzamidine (HDPBA) and multi-walled carbon nanotubes (MWCNTs) (HDPBA‒MWCNTs/CPE) has been developed. The modified electrode was applied for preconcentration and voltammetric determination of zinc ions (Zn(II)) by square wave anodic stripping voltammetry (SWASV). The preconcentration of Zn(II) on the electrode surface was performed in 0.1 M Brinton Robinson (B-R) buffer solution (pH 6) at an applied potential of -1.30 V versus Ag/AgCl for 120 s, followed by stripping in the positive potential scan of the SWASV after a quit time of 10 s. Under optimized experimental conditions, the proposed electrode exhibited a wider linear dynamic response for Zn(II) in a concentration range of 0.02-10.00 μM with a detection limit of 2.48 nM. This is due to the excellent metal-chelation property of the ligand, and the good conductivity and large surface area of MWCNTs which significantly improved the sensing performance of the nanocomposite modified electrode. The selectivity of the electrode was studied by evaluating the interference effects of various foreign ions on the peak current of Zn(II). The method exhibited high reproducibility with a relative standard deviation (RSD) of 3.1%. The present method was applied for the determination of zinc ions in water samples. The recovery values in the tested samples were found to be 98.50-106.0%, indicating a good accuracy of the proposed electrode. Furthermore, the electrochemical behavior of HDPBA in acetonitrile and aqueous solutions has been studied., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

This paper presents the fabrication of a new modified carbon paste electrode (CPE) with N 1 -hydroxy- N -diphenylbenzamidine (HDPBA) and functionalized multi-walled carbon nanotubes (MWCNTs) (HDPBA-MWCNTs/CPE) for highly sensitive and selective determination of Cu(ii) using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated electrode was characterized using various spectroscopic techniques to study its morphological, structural, and electrochemical properties. The accumulation of Cu(ii) on the surface of HDPBA-MWCNTs/CPE was done in 0.1 M ammonium chloride (NH 1 , N 2 -diphenylbenzamidine (HDPBA) and functionalized multi-walled carbon nanotubes (MWCNTs) (HDPBA-MWCNTs/CPE) for highly sensitive and selective determination of Cu(ii) using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated electrode was characterized using various spectroscopic techniques to study its morphological, structural, and electrochemical properties. The accumulation of Cu(ii) on the surface of HDPBA-MWCNTs/CPE was done in 0.1 M ammonium chloride (NH 4 Cl, pH 5) solution at an applied potential of -0.70 V versus Ag/AgCl for 180 s, followed by electrochemical stripping in the positive scan of the voltammetry after a resting time of 10 s. The developed HDPBA-MWCNTs/CPE was found to be highly selective, sensitive and reproducible. At optimal conditions of the experiment, the proposed method exhibited a very low limit of detection (0.0048 nM Cu(ii)), a wide linear dynamic range (0.00007-1.5000 μM Cu(ii)), and good reproducibility with relative standard deviation (RSD) value of 3.7%. The effect of various foreign ions on the voltammetric response of Cu(ii) was investigated and the electrode was found to be highly selective to Cu(ii). The practical applicability of the proposed HDPBA-MWCNTs/CPE was studied by applying the electrode for the quantification of Cu(ii) contents in environmental water (wastewater and tap water), soft drink (Fanta and Sprite), and food supplement (commercially available multi-mineral/vitamin tablets) samples. The present method was validated with atomic absorption spectrometry (AAS). The results found from the two methods are in good agreement with a 95% confidence level., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The present study introduces a novel electrode for rapid, highly sensitive, and selective electrochemical sensor for cadmium(II) using 5% N 1 -hydroxy-N 1 ,N 2 -diphenylbenzamidine (HDPBA) modified carbon paste electrode (CPE) (HDPBA‒CPE). Surface characterizations and structural analysis of the proposed HDPBA‒CPE were performed using several analytical techniques. The voltammetric measurements of Cd(II) were conducted by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). Several experimental conditions such as composition and pH of buffer solutions, HDPBA composition, accumulation potential and time, and other voltammetric conditions were optimized. Cd(II) was preconcentrated on the modified electrode surface for 270 s using Britton Robinson (B-R) buffer (0.1 M, pH 4) at -1.0 V versus Ag/AgCl, followed by electrochemical oxidation of the accumulated Cd(II) in the positive scan of SWASV after a quiet time of 10 s. Under optimized parameters, the proposed method showed a linear range of 0.3-100 nM Cd(II) with a detection limit of 0.032 nM. The fabricated HDPBA-modified carbon paste electrode exhibited excellent sensitivity, selectivity, stability, and reproducibility (with RSD of 3.8%). The developed HDPBA‒CPE was used for the quantification of Cd(II) in tobacco and environmental water samples, and it was found to be applicable for the determination of different types of real samples., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2022 Endale Tesfaye et al.)

Background: The deficiency of vitamin B2 can lead to many health problems. Therefore, it is necessary to develop a sensitive, selective and fast method for the determination of vitamin B2 in food samples. In this work, a sensitive, selective and low-cost electrochemical sensor was developed using poly (glutamic acid) and Zinc oxide nanoparticles (ZnO NPs) for vitamin B2 in non-alcoholic beverage and milk samples., Methods: The modification of the electrode surface was carried out by electropolymerization of glutamic acid on ZnO NPs-carbon paste electrode (ZnO NPS-CPE). The prepared electrodes were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-Ray diffraction (XRD). CV and square wave voltammetry (SWV) were used to investigate the electrochemical behavior of vitamin B2 at the modified electrode. The effect of various parameters such as amount of ZnO NPs, polymerization cycle, concentration of the monomer, pH, scan rate and accumulation time were optimized to obtain maximum sensitivity at the modified electrode., Results: The developed sensor showed high electrocatalytic activity towards vitamin B2. Under the optimized conditions, the developed sensor showed a linear response in the range 0.005-10 µM with a low detection limit of (LOD) 0.0007 ± 0.00001 µM and high sensitivity of 21.53 µA/µM., Conclusions: A reproducible, repeatable, stable and selective sensor was successfully applied for the quantification of vitamin B2 in beverage and milk samples with acceptable recoveries in the range of 88-101%., (© 2022. The Author(s).)

Ethiopia introduced the measles second dose vaccine from the routine expanded immunization program in 2018. Shreds of evidence are scarce on the measles second dose vaccination coverage and its associated factors in Ethiopia. We aimed to assess the measles second dose vaccination coverage and associated factors in Ethiopia using the recent Ethiopian Mini Demographic and Health Survey (EMDHS) 2019 data. An in-depth secondary data analysis was conducted based on the Ethiopian mini demographic and health survey 2019 data; which was a cross-sectional survey targeted on key indicators of maternal and child health. A weighted sample of 965 children was included in the analysis. A multi-level mixed effect logistics regression model was fitted. Adjusted Odds Ratio (AOR) with 95 %CI was reported for statistically significant variables. The measles second dose coverage was 12.36 % (95 %CI = 10.89, 15.44). Not vaccinated for the third dose of pentavalent vaccine (Penta 3) (AOR = 0.60, 95 %CI: 0.37, 0.95), age of the child [13 to 23 months (AOR = 2.14, 95 %CI: 1.05, 4.36), 24 to 36 months (AOR = 2.58, 95 %CI: 1.32, 5.05)], household head educational status [no education (AOR = 0.51,95 %CI: 0.26, 0.99), primary (AOR = 0.44, 95 %CI: 0.23, 0.85)], and living in south nation, nationalities and peoples region (SNNPR) (AOR = 2.83,95 %CI: 1.12, 7.11) were significantly associated with measles second dose vaccination coverage. Measles second dose vaccination coverage was low in Ethiopia. Age of the child, being vaccinated for the Penta 3, educational status of the household head, and region of residence were significant determinants of measles second dose vaccination coverage., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Background: Patient preference has preceded the use of health care services, and it has been affected by different hospital attributes. Meanwhile, the number of patients receiving vital health intervention is particularly low in Ethiopia. Therefore, this study aimed to determine the effect of hospital attributes on patient preference for outpatients in the Wolaita area in September 2020., Methods: A discrete choice experimental study was applied to determine the effect of hospital attributes on patient preference with a sample size of 1077. The experimental survey was conducted among outpatient attendants selected through a systematic random sampling approach. Six key attributes (competence of healthcare providers; availability of medical equipment and supplies; cost of service; wait time; distance; and hospital reputation) deduced from various hospital attributes were used to elicit the patient preferences. The data was collected from participants through the Open Data Kit application. A random effect probit model with marginal willingness to pay measure and partially log-likelihood analysis was applied to extract important attributes. We used STATA version 15 software for analysis, and the fitness of the model was verified by the calculated p-value for the Wald chi-square with a cut-point value of 0.05., Result: One thousand forty-five patients who received outpatient care participated in the study. The random effect probit results have shown that all hospital attributes included in the study were significantly valued by patients while choosing the hospital (p-value < 0.001). Meanwhile, based on marginal willingness to pay and partial log-likelihood analysis, the competence of health care providers was identified as the most important attribute followed by the availability of medical equipment and supplies in hospitals., Conclusion and Recommendation: The results suggested that the quality of health care providers and availability of medical equipment and supply in hospitals would be primary interventional points for improving the patient preference of hospitals. Assessment, education, and training are recommended for enhancing the quality of health care providers. And stock balance checks, inspections, and accreditation are believed to be valuable for improving the availability of equipment and supply in hospitals., (© 2022. The Author(s).)

Introduction: Cholera remains a serious public health problem characterized by a large disease burden, frequent outbreaks, persistent endemicity, and high mortality, particularly in tropical and subtropical low-income countries including Ethiopia. The recent cholera outbreak in the Somali region began on 4 September to 1 November 2019. Cholera may spread rapidly through a population so that an early detection and reporting of the cases is mandatory. This study aimed to identify determinants of cholera infection among >5 years of age population in Somali region, Ethiopia., Methods: A community-based unmatched case-control study was conducted among 228 (76 cases and 152 controls, 1:2 ratio) systematically selected population. Data were collected using a structured questionnaire administered by an interviewer and a record review. Descriptive statistics and multivariable logistic regression analysis was used to identify the determinants of the risk factors of cholera infection with a 95% confidence interval and statistical significance was declared a tap-value < 0.05., Results: A total of 228 participants (33.3% cases and 66.7% controls) were enrolled in this study. The majority of the cases were in the range of 20-49 years of age (69.7%). The odds of acquiring cholera infection increased significantly by drinking unsafe pipe water (AOR 4.3, 95% CI 1.65-11.2), not having a household level toilet/latrine (AOR 3.25, 95% CI 1.57-6.76), hand washing only sometimes after the toilet (AOR 3.04, 95% CI 1.58-5.86) and not using water purification methods (AOR 2.3, 95% CI 1.13-4.54)., Conclusion: Major risk factors for cholera infection were related to drinking water and latrine hygiene. Improvement in awareness creation about cholera prevention and control methods, including water treatment, hygiene and sanitation were crucial in combating this cholera outbreak. Primary public health actions are ensuring clean drinking water, delivery of water purification tablets, soap and hand sanitizers and provision of health care and outbreak response. Long term goals in cholera affected areas include comprehensive water and sanitation strategies. Overall, the strategic role of a multi-sectoral approach in the design and implementation of public health interventions aimed at preventing and controlling cholera are essential to avert cholera outbreaks. Preparedness should be highlighted in cholera prone areas like Somali region especially after drought periods., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Challa, Getachew, Debella, Merid, Atnafe, Eyeberu, Birhanu and Regassa.)

Background: Diabetes mellitus (DM) is a complex metabolic disorder characterized by persistent hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Type 2 DM has a strong hereditary background. A study of the dermatoglyphic features can help in the early identification of people with a genetic predisposition to develop type 2 DM., Purpose of the Study: The study was aimed to compare the finger and palmar dermatoglyphics features in type 2 diabetic and non-diabetic patients and to evaluate the association with other variables., Patients and Materials: Institution-based cross-sectional study was conducted in one referral hospital and three primary hospitals located in Gedeo Zone. Three hundred ninety study participants (130 type 2 diabetics and 260 non-diabetics) from adult OPD and diabetic clinics were included in the study. The association among different dermatoglyphics variables was analyzed using the chi-square test. An independent t -test was conducted to analyze the mean difference and to test the significance of numerical variables. A statistically significant association was declared at P-value <0.05., Results: In the present study, a total of 3900 digits (1300 from type 2 diabetic and 2600 non-diabetic) were analyzed for distribution of digital dermatoglyphic patterns. Loop pattern is found to be the commonest in both study groups with a prevalence of 65.8% and 60.7% among type 2 diabetics and non-diabetics, respectively. Both the right-left axial tri-radius angle was significantly higher in type 2 diabetes mellitus patients compared to non-diabetic study participants. Total finger ridge counts and absolute finger ridge counts showed no significant difference in both groups., Conclusion: The study revealed Loop pattern was more frequent in type 2 DM compared to non-diabetic study participants. Whorl type was more common than arch type in non-diabetic patients compared to type 2 DM groups. The result also showed tri-radius angle is significantly wider in diabetic groups in both hands., Competing Interests: The authors report no conflicts of interest for this work., (© 2022 Tadesse et al.)

In this study, cobalt nanoparticles (CoNPs) were synthesized and cobalt nanoparticles modified glassy carbon electrode (CoNPs/GCE) was prepared by drop coating the nanoparticles on glassy carbon electrode. After preparing polypyrrole modified glassy carbon electrode (PPy/GCE) using electropolymerization of pyrrole in LiClO 4 solution, cobalt nanoparticles-polypyrrole composite modified glassy carbon electrode (CoNPs/PPy/GCE) was fabricated by drop coating the CoNPs on the PPy/GCE. Different characterization techniques such as scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, FTIR spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry were used to study the morphological structure and electrochemical behavior of the sensors. The results demonstrated that PPy chains interacted with CoNPs through donor-acceptor bonds. Among all the electrodes, CoNPs/PPy/GCE exhibited highest electroactive surface area and lowest electron transfer resistance towards phoxim. Under the optimal conditions, the sensor showed linear relationship between the reduction peak current and the concentration of phoxim in the range of 0.025 μM-12 μM with the detection limit as 4.5 nM. Besides, the composite electrode demonstrated excellent reproducibility, good stability and selectivity towards the possible interfering substances. All of these properties made CoNPs/PPy/GCE a suitable electrochemical sensor for the electrochemical determination of phoxim in water samples using square wave voltammetry., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 Published by Elsevier B.V.)

In this study, an electrochemical sensor based multiwalled carbon nanotubes (MWCNTs)-poly (4-amino-3-hydroxy naphthalene sulfonic acid) modified glassy carbon electrode (MWCNTs/poly (AHNSA)/GCE) was developed for the determination of uric acid (UA). The composite electrode was prepared first by electropolymerization of the monomer (AHNSA) on GCE using cyclic voltammetry within the potential range of -0.8 V to +2.0 V vs Ag/AgCl for 15 cycles followed by drop coating of MWCNTs solution on the surface of poly (AHNSA)/GCE. Under optimal conditions, MWCNTs/poly (AHNSA)/GCE showed a linear current response with UA concentrations in the range of 1 × 10 -6 to 1 × 10 -4 M with R 2 = 0.9972. The sensor exhibited low detection limit with a value of 0.024 μM. The sensors have been applied to successfully quantify UA in urine samples., Competing Interests: The authors declare no conflict of interest., (© 2021 The Author(s).)

We investigated the possibility of band structure engineering of pyroxene silicates with chemical formula A +1 B +3 Si 2 O 6 by proper cation substitution. Typically, band gaps of naturally formed pyroxene silicates such as NaAlSi 2 O 6 are quite high (≈5 eV). Therefore, it is important to find a way to reduce band gaps for these materials below 3 eV to make them usable for optoelectronic applications operating at visible light range of the spectrum. Using first-principles calculations, we found that appropriate substitutions of both A + and B 3+ cations can reduce the band gaps of these materials to as low as 1.31 eV. We also discuss how the band gap in this class of materials is affected by cation radii, electronegativity of constituent elements, spin-orbit coupling, and structural modifications. In particular, the replacement of Al 3+ in NaAlSi 2 O 6 by another trivalent cation Tl 3+ results in the largest band-gap reduction and emergence of intermediate bands. We also found that all considered materials are still thermodynamically stable. This work provides a design approach for new environmentally benign and abundant materials for use in photovoltaics and optoelectronic devices., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Multilayer coatings consisting of oppositely charged polyelectrolytes have proven to be extraordinarily effective oxygen barriers but require many processing steps to fabricate. In an effort to prepare high oxygen barrier thin films more quickly, a polyelectrolyte complex coacervate composed of polyethylenimine and polyacrylic acid is prepared. The coacervate fluid is applied as a thin film using a rod coating process. With humidity and thermal post-treatment, a 2 µm thin film reduces the oxygen transmission rate of 0.127 mm poly(ethylene terephthalate) by two orders of magnitude, rivalling conventional oxygen barrier technologies. These films are fabricated in ambient conditions using low-cost, water-based solutions, providing a tremendous opportunity for single-step deposition of polymeric high barrier thin films., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Poly(4-amino-3-hydroxynaphthalene sulfonic acid)-modified glassy carbon electrode (poly(AHNSA)/GCE) was prepared for simultaneous determination of caffeine and paracetamol using square-wave voltammetry. The method was used to study the effects of pH and scan rate on the voltammetric response of caffeine and paracetamol. Linear calibration curves in the range of 10-125μM were obtained for both caffeine and paracetamol in acetate buffer solution of pH 4.5 with a correlation coefficient of 0.9989 and 0.9986, respectively. The calculated detection limits (S/N=3) were 0.79μM for caffeine and 0.45μM for paracetamol. The effects of some interfering substances in the determination of caffeine and paracetamol were also studied and their interferences were found to be negligible which proved the selectivity of the modified electrode. The method was successfully applied for the quantitative determination of caffeine and paracetamol in Coca-Cola, Pepsi-Cola and tea samples., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Screen printed carbon electrode (SPCE) has been modified with single wall carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) composites for the determination of phenol and chlorophenols (phenol, 4-chlorophenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol). The effect of the modifiers on the electrode characteristics was evaluated and the responses were optimized for the voltammetric determination of phenol and chlorophenols. The parameters affecting the responses such as pH, scan rate, and stability were studied. The analytical performance of the SWCNT/PEDOT/SPCE using cyclic voltammetry was tested and found to be impressive. Under these conditions, the designed electrode showed a good performance for the voltammetric measurements of the phenolic compounds. The modified SPCE, when it is compared with other enzymatic and nonenzymatic sensors, showed a wider dynamic range for the detection of the phenolic compounds. The modified SPCE was used for the quantification of phenol in water samples. The results suggest that the method is quite useful for analyzing and monitoring phenols and chlorophenols.

An iron(III) doped zeolite modified glassy carbon electrode was constructed for the determination of pyridine-2-aldoxime methochloride. X-ray diffraction and chemical analysis were utilized to determine the optimum pH and chemical content for doping zeolite. Cyclic voltammetry was used to characterize the modified electrode and study the kinetics of the acid treated and untreated modified electrode. Acid treatment of the modified electrode showed a better electrochemical behavior compared to the untreated iron(III) doped zeolite modified electrode. Square wave anodic stripping voltammetry was employed to investigate the working pH and preconcentration time. The analytical performance of the modified electrode was evaluated, and a linear anodic stripping response for pyridine-2-aldoxime methochloride in the concentration range of 0.5-100.0 μM with a detection limit of 1.61 × 10(-7) M was obtained. Finally, the developed method was successfully applied for the determination of pyridine-2-aldoxime methochloride in a biological sample.

Antidepressant treatments, including those that increase serotonin (5-HT) neurotransmission, require several weeks or months until the onset of the therapeutic effect in depressed patients. The negative feedback on 5-HT transmission exhibited by the 5-HT(1A) and 5-HT(1B) autoreceptors has been postulated as a possible delaying factor. The aim of the present study was to assess the effect of the acute and subchronic treatment with pindolol, a 5-HT(1A/1B,) β₁ and β₂ adrenoceptor antagonist, on 5-HT synthesis, one of the key parameters of 5-HT neurotransmission. Male Sprague-Dawley (SPD) rats (180-220 g) were treated with pindolol or an adequate volume of saline, administered either acutely (15 mg/kg i.p.; SPD-AC-SAL, SPD-AC-TR) or subchronically (15 mg/kg day i.p. for 7 days; SPD-SUBCHR-SAL, SPD-SUBCHR-TR). Thirty minutes following the single i.p. injection (acute experiment) or at the 8th day following the commencement of the subchronic treatment (subchronic experiment), 5-HT synthesis was measured using α-[¹⁴C]methyl-L-tryptophan autoradiography. The analysis of variance (ANOVA), followed by the Benjamini-Hochberg correction for multiple comparisons, revealed: (1) a significant increase of 5-HT synthesis in the SPD-AC-TR rats, relative to the SPD-AC-SAL rats in all brain regions examined except the substantia nigra--pars reticularis, dorsal subiculum, inferior olive, raphe magnus and raphe obscurus and (2) a significant increase of 5-HT synthesis in the SPD-SUBCHR-TR rats, relative to the SPD-SUBCHR-SAL rats in all brain regions except the median raphe, hypothalamus and raphe pontine. On the basis of these results, we hypothesized that the antagonism of the 5-HT(1A/1B) receptors prevents the negative feedback mediated by these receptors on 5-HT synthesis, resulting in a persistent increase of 5-HT synthesis. The results accord with clinical reports on the utility of pindolol in the augmentation of antidepressant treatment., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

In this paper we present the results of empirical potential and density functional theory (DFT) studies of models of interfaces between amorphous silicon (a-Si) or hydrogenated amorphous Si (a-Si:H) and crystalline Si (c-Si) on three unreconstructed silicon surfaces, namely (100), (110) and (111). In preparing models of a-Si on c-Si, melting simulations are run with classical molecular dynamics (MD) at 3000 K for 10 ps to melt part of the crystalline surface and the structure is quenched to 300 K using a quench rate of 6 × 10(12) K s(-1) and finally relaxed with DFT. Incorporating the optimum hydrogen content in a-Si to passivate undercoordinated Si, followed by DFT relaxation, produces hydrogenated amorphous silicon on crystalline surfaces, a-Si:H/c-Si. The (100) surface is the least stable crystalline surface and forms the thickest amorphous Si region, while the most stable (110) surface forms the smallest amorphous region. Calculated radial distribution functions (RDF) in the amorphous and crystalline layers are consistent with a-Si and c-Si and indicate a structural interface region one layer thick. The electronic density of states shows an evolution from c-Si to a-Si (or a-Si:H), with a larger electronic interface layer, suggesting that the electronic properties are more strongly perturbed by interface formation compared to the atomic structure. The computed optical absorption spectra show strong effects arising from the formation of different a-Si and a-Si:H regions in different Si surfaces.

Glassy carbon electrode was modified by electropolymerization of 4-amino-3-hydroxynaphthalene sulfonic acid. Cyclic voltammetric study of quinine showed higher current response at the modified electrode compared to the bare and activated glassy carbon electrodes in pH 7.0 phosphate buffer solution. Under optimized conditions, a calibration curve was obtained by square wave voltammetry at the modified electrode. The linear relationship between the peak current and the concentration of quinine in the range of 1.0 × 10(-7) to 1.0 × 10(-5) M was I (pa) (in microamperes) = 6.26C (in micromolars) + 0.2997 (R (2) = 0.999). The detection limit calculated (S/N = 3) was 1.42 × 10(-8) M, which is much lower than similar reports. The method was successfully applied for the determination of quinine in spiked human urine, and pharmaceutical formulations and recovery values >90 % were obtained.

The effects of the administration of the serotonin (5-HT)(2A) antagonist, M100907, on 5-HT synthesis rates, were evaluated using the α-[(14)C]methyl-l-tryptophan (α-MTrp) autoradiographic method. In the treatment study, M100907 (10mg/kg) was injected intraperitoneally 30 min before the α-MTrp injection (30 μCi over 2 min). A single dose of M100907 caused a significant decrease in the synthesis in the anterior olfactory nucleus, accumbens nucleus, frontal cortex, sensory-motor cortex, cingulate cortex, medial caudate-putamen, dorsal thalamus, substantia nigra, inferior collicus, raphe magnus nucleus, superior olive, and raphe pallidus nucleus. These data suggest that the terminal 5-HT(2A) receptors are involved in the regulation of 5-HT synthesis in the entire brain. Further, 5-HT synthesis is likely regulated by the 5-HT(2A) antagonistic property of M100907 in the cortices, anterior olfactory nucleus, caudate putamen, and nucleus accumbens., (Copyright © 2011 Elsevier Inc. All rights reserved.)

A sensitive and selective method was developed for the determination of N-acetyl-p-aminophenol (APAP) and p-aminophenol (PAP) using poly(3,4-ethylenedioxythiophene) (PEDOT)-modified glassy carbon electrode (GCE). Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical reaction of APAP and PAP at the modified electrode. Both APAP and PAP showed quasireversible redox reactions with formal potentials of 367 mV and 101 mV (vs. Ag/AgCl), respectively, in phosphate buffer solution of pH 7.0. The significant peak potential difference (266 mV) between APAP and PAP enabled the simultaneous determination both species based on differential pulse voltammetry. The voltammetric responses gave linear ranges of 1.0×10(-6)-1.0×10(-4) mol L(-1) and 4.0×10(-6)-3.2×10(-4) mol L(-1), with detection limits of 4.0×10(-7) mol L(-1) and 1.2×10(-6) mol L(-1) for APAP and PAP, respectively. The method was successfully applied for the determination of APAP and PAP in pharmaceutical formulations and biological samples., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Few studies have systematically addressed evolutionary changes in olfactory neuron assemblies, either by genetic drift or as an adaptation to specific odor environments. We have studied the sense of olfaction in 2 congeneric scarab beetles, Pachnoda interrupta Olivier and Pachnoda marginata Drury (Coleoptera: Scarabaeidae: Cetoniinae), which are both opportunistic polyphages, feeding mainly on fruit and flowers. The 2 species occur in dissimilar habitats: P. interrupta is found in dry savannah, and P. marginata in tropical parts of equatorial Africa. To study how these species may have adapted their sense of olfaction to their odor environments, we utilized single-unit electrophysiology on olfactory sensilla with a wide selection of food-related compounds. Despite the differences in habitat, we found that the species shared most of the physiological types of olfactory receptor neurons (ORNs) encountered, although their proportions frequently varied between the species. The high degree of conservation in olfaction between the species implies that a similar sensory strategy is efficient for food search in both habitats. However, shifts in proportions of receptor neuron classes, and slight shifts in response profiles and/or presence of some ORN classes unique to either species, may reflect adaptation to a different set of hosts., (© The Author 2011. Published by Oxford University Press. All rights reserved.)

Adults of the sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), form aggregations during the mating period in July, but also in October. The beetles aggregate on food sources, e.g., Acacia spp. trees or sorghum with ripe seeds, to feed and mate. During the mating season, field trapping experiments with live beetles as bait demonstrated attraction of males to unmated females, but not to mated females or males, indicating the presence of a female-emitted sex pheromone. Unmated females combined with banana (food source) attracted significantly more males and females than did unmated females alone. Other combinations of beetles with banana were not more attractive than banana alone. Thus, aggregation behavior appears to be guided by a combination of pheromone and host volatiles. Females and males were extracted with hexane during the mating period, and the extracts were compared by using GC-MS. In a field trapping experiment, 19 compounds found only in females were tested, both singly and in a mixture. Traps baited with one of the female-associated compounds, phenylacetaldehyde, caught significantly more beetles than any other treatment. However, the sex ratio of beetles caught in these traps did not differ from that of control traps, and it is possible that other components may be involved in the sex pheromone signal. Furthermore, traps baited with a mixture of all 19 compounds attracted significantly fewer beetles than did phenylacetaldehyde alone.

The sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), is a key pest on sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Ethiopia. At present there is a lack of efficient control methods. Trapping shows promise for reduction of the pest population, but would benefit from the development of attractive lures. To find attractants that could be used for control of P. interrupta, either by mass trapping or by monitoring as part of integrated pest management, we screened headspace collections of sorghum and the highly attractive weed Abutilon figarianum Webb (Malvaceae) for antennal activity using gas chromatograph-coupled electroantennographic detection (GC-EAD). Compounds active in GC-EAD were identified by combined gas chromatography and mass spectrometry (GC-MS). Field trapping suggested that attraction is governed by a few influential compounds, rather than specific odor blends. Synthetic sorghum and abutilon odor blends were attractive, but neither blend outperformed the previously tested attractants eugenol and methyl salicylate, of which the latter also was part of the abutilon blend. The strong influence of single compounds led us to search for novel attractive compounds, and to investigate the role of individual olfactory receptor neurons (ORNs) in the perception of kairomones. We screened the response characteristics of ORNs to 82 putative kairomones in single sensillum recordings (SSR), and found a number of key ligand candidates for specific classes of ORNs. Out of these key ligand candidates, six previously untested compounds were selected for field trapping trials: anethole, benzaldehyde, racemic 2,3-butanediol, isoamyl alcohol, methyl benzoate and methyl octanoate. The compounds were selected on the basis that they activated different classes of ORNs, thus allowing us to test potential kairomones that activate large non-overlapping populations of the peripheral olfactory system, while avoiding redundant multiple activations of the same ORN type. Field trapping results revealed that racemic 2,3-butanediol is a powerful novel attractant for P. interrupta.

In this paper a simple and highly sensitive electroanalytical method for the determination of caffeine content using 1,4-benzoquinone modified carbon paste electrode is presented. The method is based on suppression of 1,4-benzoquinone peak current on addition of caffeine. Square-wave and cyclic voltammetric techniques were utilised for the investigation. The 1,4-benzoquinone modified electrode exhibited a well-defined peak with reproducible peak current values for repetitive measurements; and showed a decrease in peak current value with an increase in caffeine content. The result revealed two linear range regions between 0 mmol L(-1) and 0.5 mmol L(-1) and 0.5 mmol L(-1) and 8.0 mmol L(-1), with detection limits of 0.3 micromol L(-1) and 5.1 micromol L(-1), respectively. The method was then successfully applied to the determination of caffeine content in coffee samples. The effects of pH, electrode composition, step potential, pulse amplitude and square-wave frequency on the voltammetric responses were also investigated.

The effects of acute and repeat administration of the serotonin (5-HT)(1) agonists TFMPP [N -(3-trifluoromethyl)phenylpiperazine hydrochloride] and CGS12066B [7-trifluoromethyl-4- (4-methyl-1-piperazinyl)pyrrolo[1,2-a ]-quinoxaline dimaleate] were evaluated on 5-HT synthesis rates using the alpha-[(14) C]methyl-l-tryptophan (alpha-MTrp) autoradiographic method. In the acute treatment study, TFMPP (10 mg/kg) and CGS12066B (5 mg/kg) were injected intraperitoneally 30 min before an alpha-MTrp injection. In an acute study TFMPP reduced overall brain 5-HT synthesis, in the dorsal and median raphe, and in almost all of their projection areas, with the exception of the parietal, sensory-motor, and frontal cortices, the accumbens nucleus, and the caudate. Acute CGS12066B treatment did not have overall significant effect, but the rates did decrease in the cell body areas of 5-HT neurons. In a 7-day treatment with TFMPP (10 mg/kg/day) or CGS12066B (5 mg/kg/day), the 5-HT synthesis rates (24 h after last dose) decrease, with both compounds, in almost all of the nerve terminal structures. TFMPP reduced the synthesis in the dorsal and median raphe, while CGS12066B reduced it only in the dorsal raphe. This data suggests that after a 7-day treatment with TFMPP and CGS12066B, the rate of 5-HT synthesis in the dorsal raphe is restored and is reduced in many projection areas. The observed effects in the 7-day treatment could also be related to actions through the postsynaptic 5-HT(1B) sites and/or other 5-HT receptors since this compounds have limited selectivity.

The effects of acute and chronic administration of WAY100635 and WAY100135, serotonin (5-HT)1A antagonists, on 5-HT synthesis rates, calculated from the trapping of alpha-[14C]methyl-L-tryptophan (alpha-MTrp), were evaluated in the rat brain using autoradiography. In the acute treatment studies, WAY100635 (1 mg/kg) induced a significant increase in 5-HT synthesis in the median raphe nucleus and some nerve terminal structures (range between 18 and 53%), while WAY100135 (10 mg/kg) produced a significant decrease of synthesis, in the range between 16 and 33%, in the raphe magnus nucleus and several projection areas. The action of WAY100635 given acutely was likely a result of antagonist actions at the 5-HT1A somato-dendritic autoreceptors. WAY100135 probably acted acutely as a partial agonist. In the chronic treatment studies, WAY100635 (1 mg/kg/day) and WAY100135 (10 mg/kg/day) were administered for 7 days as s.c. injections once a day. Chronic treatment with both compounds significantly reduced the rate of 5-HT synthesis in the nerve terminal structures and produced a significant increase in the raphe nuclei. These treatments did not have any effect on the plasma free or total tryptophan.