Positive Ratio Research Articles

Thin Zinc Electrodes Stabilized with Organobromine‐Partnered H2O−Zn−MeOH Cluster Ions for Practical Zinc‐Metal Pouch Cells

AbstractThe utilization of thin zinc (Zn) anodes with a high depth of discharge is an effective strategy to increase the energy density of aqueous Zn metal batteries (ZMBs), but challenged by the poor reversibility of Zn electrode due to the serious Zn‐consuming side reactions at the Zn||electrolyte interface. Here, we introduce 2‐bromomethyl‐1,3‐dioxolane (BDOL) and methanol (MeOH) as electrolyte additive into aqueous ZnSO4 electrolyte. In the as‐formulated electrolyte, BDOL with a strong electron‐withdrawing group (−CH2Br) tends to pair with the H2O−Zn−MeOH complex, leading to the formation of organobromine‐partnered H2O−Zn−MeOH cluster ions. During the Zn electrodeposition process, the formed ZnO‐dominated by‐products induce the polymerization of BDOL monomers, which are previously adsorbed on the electrode. As a result, a uniform dual‐layer SEI with ZnO‐dominated outer layer and polyether‐dominated inner layer is built on the surface of Zn electrode. With such an in situ formed dual‐layer SEI, the Zn||Mg0.9Mn3O7 ⋅ 2.7H2O pouch cell using a 10‐um Zn anode (corresponding to a low negative to positive areal capacity ratio of 3.56) successfully operated for 300 cycles with a high capacity retention of 86 %, promising a high practical energy density of >120 Wh/kg (based on the total mass of Zn and Mg0.9Mn3O7 ⋅ 2.7H2O).

The Impact of Radioactive Iodine on Disease-Specific Survival in Low-to-Intermediate Risk N1b Papillary Thyroid Carcinoma.

The association of radioactive iodine (RAI) with disease-specific survival (DSS) is controversial in N1b papillary thyroid carcinoma (PTC). We aimed to evaluate whether RAI is associated with DSS in low-to-intermediate-risk N1b PTC. The Surveillance, Epidemiology, and End Results database was queried for pT1-3, N1b, M0/Mx classic PTC treated with total thyroidectomy. Multivariable Cox regression was performed to identify predictors of DSS. Subanalyses were conducted for age, intermediate-risk versus otherwise low-risk features, and positive lymph node ratio (LNR) > 0.17. Radioactive iodine recipients were younger (43.0 vs. 44.0 years, p = 0.036) with increased capsular or local invasion (49.2% vs. 41.9%, p < 0.001) and median LNR (0.37 vs. 0.33, p = 0.001). Worse DSS was associated with age (adjusted-HR = 1.09, p < 0.001), tumor size (adjusted-HR = 1.02, p < 0.001), and local invasion (adjusted-HR = 1.86, p = 0.003). Radioactive iodine was associated with improved DSS in the whole cohort (adjusted-HR = 0.61, p = 0.014), in patients ≥ 55 years (adjusted-HR = 0.48, p = 0.001) and in patients ≥55 years with LNR > 0.17 (adjusted-HR = 0.45, p = 0.001) but not LNR ≤ 0.17. Radioactive iodine was not associated with a DSS benefit in patients < 55 years even when stratified by LNR 0.17. Radioactive iodine administered to patients with at least one intermediate-risk feature (> 5 pathologic LNs or any local invasion) was associated with improved DSS (adjusted-HR = 0.60, p = 0.019) but not those with otherwise low-risk features (adjusted-HR = 0.71, p = 0.502). Radioactive iodine is associated with improved DSS in N1b PTC patients with intermediate-risk features, age ≥ 55 years, and LNR > 0.17 in older patients, but not in patients with otherwise low-risk features. These factors could help guide RAI utilization in N1b PTC.

Impact of contralateral occult neck metastasis in HPV-associated tonsil cancer: Is elective contralateral neck dissection required?

Background: Contralateral elective neck dissection in human papillomavirus (HPV)- associated tonsil cancer is a matter of debate.Objectives: The aim of this study was to analyze rates of contralateral lymph node (LN) metastasis and their prognostic effects on HPV-associated tonsil cancer. We also assessed the necessity of elective contralateral neck dissection.Methods: To investigate the pathologic incidence of and risk factors for contralateral nodal disease in HPV-associated tonsil cancer treated with upfront primary surgery and bilateral neck dissection, the records of 68 patients were reviewed.Results: Six (8.8%) patients displayed pathologic contralateral nodal disease; four of the patients had LN metastasis confirmed in contralateral level II, one patient had LN metastasis in level III, and one patient had multi-level metastasis in contralateral levels II and III. Contralateral LN metastasis showed a significant association with greater depth of invasion (DOI) in primary tumor (p=0.032), count of positive LN (p=0.008), and positive LN ratio of the ipsilateral neck (p=0.01). Patients with contralateral LN metastasis showed a significantly worse five-year overall survival but no significant difference in disease-free survival.Conclusion: HPV-associated tonsil cancer has exceedingly low rates of occult contralateral LN metastasis. However, in cases of ipsilateral multiple node metastases and higher DOI, it may be worth considering elective contralateral neck dissection based on the risk of occult metastasis.

Artificial intelligence-guided screening of under-recognized cardiomyopathies adapted for point-of-care echocardiography

Abstract Background Point-of-care ultrasonography (POCUS) enables access to cardiac imaging directly at the bedside but is limited by brief acquisition, variation in acquisition quality, and lack of advanced protocols. Purpose To develop and validate deep learning models for detecting underdiagnosed cardiomyopathies on cardiac POCUS, leveraging a novel acquisition quality-adapted modeling strategy. Methods To develop the models, we identified transthoracic echocardiograms (TTEs) of patients across five hospitals in a large U.S. health system with transthyretin amyloid cardiomyopathy (ATTR-CM, confirmed by Tc99m-pyrophosphate imaging), hypertrophic cardiomyopathy (HCM, confirmed by cardiac magnetic resonance), and random controls from the same period enriched for the presence of severe AS. In a sample of 290,245 TTE videos, we used novel augmentation approaches and a customized loss function to weigh image and view quality to train a multi-label, view agnostic video-based convolutional neural network (CNN) to discriminate the presence of ATTR-CM, HCM, and/or AS+ and AS- controls. Models were tested across 3,758 real-world POCUS videos from 1,879 studies in 1,330 independent emergency department (ED) patients from 2011 through 2023 (A). Results Our multi-label, view-agnostic classifier demonstrated state-of-the-art performance in discriminating ATTR-CM (AUROC 0.98 [95%CI: 0.96-0.99]) and HCM (AUROC 0.95 [95% CI: 0.94-0.96]) on standard TTE studies. Automated metrics of anatomical view correctness confirmed significantly lower quality in POCUS vs TTE videos (median view classifier confidence of 0.63 [IQR: 0.44-0.88] vs 0.93 [IQR: 0.69-1.00], p&amp;lt;0.001). When deployed to POCUS videos, our algorithm effectively discriminated ATTR-CM and HCM with AUROC of up to 0.94 (parasternal long-axis (PLAX)), and 0.85 (apical 4 chamber (A4C)) (B), corresponding to positive diagnostic odds ratios of 46.7, and 25.5, respectively. In total, 18/35 (51.4%) of ATTR-CM and 32/57 (41.1%) of HCM patients in the POCUS cohort had a positive AI screen in the year before their eventual confirmatory imaging (C). Conclusions We define and validate an AI framework that enables scalable, opportunistic screening of under-diagnosed cardiomyopathies using POCUS.

Numerical study on structural design and mechanical analysis of anti-migration tracheal stent with non-uniform Poisson's ratio

Stent migration is one of the common complications after tracheal stent implantation. The causes of stent migration include size mismatch between the stent and the trachea, physiological movement of the trachea, and so on. In order to solve the above problems, this study designed a non-uniform Poisson ratio tracheal stent by combining the size and structure of the trachea and the physiological movement of the trachea to improve the migration of the stent, meanwhile ensuring the support of the stent. In this study, the stent corresponding to cartilage was constructed with negative Poisson's ratio, and the stent corresponding to the circular connective tissue and muscular membrane was constructed with positive Poisson's ratio. And four kinds of non-uniform Poisson's ratio tracheal stents with different link lengths and negative Poisson's ratio were designed. Then, this paper numerically simulated the expansion and rebound process of the stent after implantation to observe the support of the stent, and further simulated the stretch movement of the trachea to calculate the diameter changes of the stent corresponding to different negative Poisson's ratio structures. The axial migration of the stent was recorded by applying different respiratory pressure to the wall of the tracheal wall to evaluate whether the stent has anti-migration effect. The research results show that the non-uniform Poisson ratio stent with connecting rod length of 3 mm has the largest diameter expansion in the negative Poisson ratio section when the trachea was stretched. Compared with the positive Poisson's ratio structure, the axial migration during vigorous breathing was reduced from 0.024 mm to 0.012 mm. The negative Poisson's ratio structure of the non-uniform Poisson's ratio stent designed in this study did not fail in the tracheal expansion effect. Compared with the traditional stent, the non-uniform Poisson's ratio tracheal stent has an anti-migration effect under the normal movement of the trachea while ensuring the support force of the stent.

Quercetin ameliorates senescence and promotes osteogenesis of BMSCs by suppressing the repetitive element‑triggered RNA sensing pathway.

Cell senescence impedes the self‑renewal and osteogenic capacity of bone marrow mesenchymal stem cells (BMSCs), thus limiting their application in tissue regeneration. The present study aimed to elucidate the role and mechanism of repetitive element (RE) activation in BMSC senescence and osteogenesis, as well as the intervention effect of quercetin. In an H2O2‑induced BMSC senescence model, quercetin treatment alleviated senescence as shown by a decrease in senescence‑associated β‑galactosidase (SA‑β‑gal)‑positive cell ratio, increased colony formation ability and decreased mRNA expression of p21 and senescence‑associated secretory phenotype genes. DNA damage response marker γ‑H2AX increased in senescent BMSCs, while expression of epigenetic markers methylation histone H3 Lys9, heterochromatin protein 1α and heterochromatin‑related nuclear membrane protein lamina‑associated polypeptide 2 decreased. Quercetin rescued these alterations, indicating its ability to ameliorate senescence by stabilizing heterochromatin structure where REs are primarily suppressed. Transcriptional activation of REs accompanied by accumulation of cytoplasmic double‑stranded (ds)RNA, as well as triggering of the RNA sensor retinoic acid‑inducible gene I (RIG‑I) receptor pathway in H2O2‑induced senescent BMSCs were shown. Similarly, quercetin treatment inhibited these responses. Additionally, RIG‑I knockdown led to a decreased number of SA‑β‑gal‑positive cells, confirming its functional impact on senescence. Induction of senescence or administration of dsRNA analogue significantly hindered the osteogenic capacity of BMSCs, while quercetin treatment or RIG‑I knockdown reversed the decline in osteogenic function. The findings of the current study demonstrated that quercetin inhibited the activation of REs and the RIG‑I RNA sensing pathway via epigenetic regulation, thereby alleviating the senescence of BMSCs and promoting osteogenesis.

Tuning solvation behavior within electric double layer via halogenated MXene for reliable lithium metal batteries

Solid electrolyte interphase (SEI)/electrolyte interface is critical in determining the lithium (Li) plating/stripping behavior. The solvation structure of Li-ion is well understood in the bulk electrolyte. Still, the mechanism of how SEI components affect the Li-ion solvation structure and desolvation energy barrier at the SEI/electrolyte interface is still unclear. Herein, Ti3C2 Maxine with single halogenated terminations (−Cl, −Br, −I) are synthesized and used as a model system, because their surface terminations induce a double halide-rich SEI formation (LiF and LiCl/LiBr/LiI). We examine the influence of the interaction strength between different Li halides and Li-ion on coordination number of Li ions and distribution of Li ions within the inner Helmholtz plane (IHP). A solvation sheath with a low solvent coordination number forms near the IHP of the LiBr interphase, improving the kinetics of Li deposition. Accordingly, half-cells utilising Li-carbon fiber/Ti3C2Br2 electrodes exhibit a long lifespan of 12,000 h (1 mA cm−2, 1 mAh cm−2). A pouch cell comprising Li-carbon fiber/Ti3C2Br2 anode and LiFePO4 cathode displays a capacity retention rate of 97 % after 300 cycles even at a low negative to positive electrode capacity ratio of 2.26. Our research provides crucial principles for the design of SEI components in Li metal batteries.

Investigation of optical fiber line with a positive transmission ratio of analog microwave signal

The influence of optical radiation power on the one-decibel compression point, harmonic distortion and dynamic range due to interference in a fiber-optic transmission line of an ultra-high frequency (microwave) signal has been studied. The line had a positive microwave signal transmission coefficient, and there were no amplification elements between the input and output. The amplification effect was achieved through the use of increased power of the carrier optical radiation and a photodetector with a high photocurrent. It has been shown that an increase in optical radiation power leads to a decrease in one-dB compression power and an increase in harmonic distortion, but an increase in optical radiation power does not lead to a change in the dynamic range of interference. It was found that the dynamic range free from interference was about 85…87 dB.

Thin Zinc Electrodes Stabilized with Organobromine-Partnered H2O-Zn-MeOH Cluster Ions for Practical Zinc-Metal Pouch Cells.

The utilization of thin zinc (Zn) anodes with a high depth of discharge is an effective strategy to increase the energy density of aqueous Zn metal batteries (ZMBs), but challenged by the poor reversibility of Zn electrode due to the serious Zn-consuming side reactions at the Zn||electrolyte interface. Here, we introduce 2-bromomethyl-1,3-dioxolane (BDOL) and methanol (MeOH) as electrolyte additive into aqueous ZnSO4 electrolyte. In the as-formulated electrolyte, BDOL with a strong electron-withdrawing group (-CH2Br) tends to pair with the H2O-Zn-MeOH complex, leading to the formation of organobromine-partnered H2O-Zn-MeOH cluster ions. During the Zn electrodeposition process, the formed ZnO-dominated by-products induce the polymerization of BDOL monomers, which are previously adsorbed on the electrode. As a result, a uniform dual-layer SEI with ZnO-dominated outer layer and polyether-dominated inner layer is built on the surface of Zn electrode. With such an in-situ formed dual-layer SEI, the Zn||Mg0.9Mn3O7·2.7H2O pouch cell using a 10-um Zn anode (corresponding to a low negative to positive areal capacity ratio of 3.56) successfully operated for 300 cycles with a high capacity retention of 86%, promising a high practical energy density of > 120 Wh/kg (based on the total mass of Zn and Mg0.9Mn3O7·2.7H2O).

Surface matching design of carbon fiber composite honeycomb

Applying carbon fiber composite honeycomb in curved sandwich shells faces challenges due to the saddle-shaped bending surface in hexagon configurations and potential damage during the shape-forming process. This study analyzes the bending deformation of honeycombs by developing large deformation theoretical model for their bending surfaces. The study introduces two novel honeycomb configurations—Boomerang-shaped with a positive Poisson's ratio and Jellyfish-shaped with a negative Poisson's ratio—achieved through curved-wall design and fabrication using a modified carbon fiber composite tape winding molding process. Experimental tests, including bending deformation and shape-forming tests, measure the three-dimensional bending surfaces and mechanical responses of carbon fiber composite honeycombs. Additionally, a developed finite element model analyzes the damage states of various carbon fiber composite honeycombs during shape-forming processes. The results reveal the bending deformation of carbon fiber composite honeycombs and present damage state cloud maps to facilitate the optimal matching of objective sandwich shells with minimal scathe.

Non-additive expression genes play a critical role in leaf vein ratio heterosis in Nicotiana tabacum L.

Heterosis, recognized for improving crop performance, especially in the first filial (F1) generation, remains an area of significant study in the tobacco industry. The low utilization of leaf veins in tobacco contributes to economic inefficiency and resource waste. Despite the positive impacts of heterosis on crop genetics, investigations into leaf-vein ratio heterosis in tobacco have been lacking. Understanding the mechanisms underlying negative heterosis in leaf vein ratio at the molecular level is crucial for advancing low vein ratio leaf breeding research. This study involved 12 hybrid combinations and their parental lines to explore heterosis associated with leaf vein ratios. The hybrids displayed diverse patterns of positive or negative leaf vein ratio heterosis across different developmental stages. Notably, the F1 hybrid (G70 × Qinggeng) consistently exhibited substantial negative heterosis, reaching a maximum of -19.79% 80 days after transplanting. A comparative transcriptome analysis revealed that a significant proportion of differentially expressed genes (DEGs), approximately 39.04% and 23.73%, exhibited dominant and over-dominant expression patterns, respectively. These findings highlight the critical role of non-additive gene expression, particularly the dominance pattern, in governing leaf vein ratio heterosis. The non-additive genes, largely associated with various GO terms such as response to abiotic stimuli, galactose metabolic process, plant-type cell wall organization, auxin-activated signaling pathway, hydrolase activity, and UDP-glycosyltransferase activity, were identified. Furthermore, KEGG enrichment analysis unveiled their involvement in phenylpropanoid biosynthesis, galactose metabolism, plant hormone signal transduction, glutathione metabolism, MAPK signaling pathway, starch, and sucrose metabolism. Among the non-additive genes, we identified some genes related to leaf development, leaf size, leaf senescence, and cell wall extensibility that showed significantly lower expression in F1 than in its parents. These results indicate that the non-additive expression of genes plays a key role in the heterosis of the leaf vein ratio in tobacco. This study marks the first exploration into the molecular mechanisms governing leaf vein ratio heterosis at the transcriptome level. These findings significantly contribute to understanding leaf vein ratios in tobacco breeding strategies.

Concordance between a New Rapid Point-Of-Care Assay and Standard ELISA in the Detection of Cysticercosis Antigens in Urine.

Neurocysticercosis is a parasitic disease of major public health importance. Definitive diagnosis requires neuroimaging, which is typically unavailable in rural impoverished regions of endemicity. Screening immunoassays can support diagnosis in this setting by identifying individuals most likely to have severe forms of disease for referral to imaging. Urine sampling is convenient, painless, and generally well accepted. We developed a rapid point-of-care (POC) assay to detect urinary antigens and assessed concordance with a standard antigen ELISA (Ag-ELISA), both using monoclonal antibodies TsW8/TsW5. From 28,145 stored community samples with Ag-ELISA results, we selected 843 for comparison, 281 each from nonreactive (ratio <1), reactive-below-cutoff (ratio 1:3), and positive (ratio ≥3) samples. Overall agreement was 73.6%, with strong agreement observed in the nonreactive (280/281, 99.6%) and positive (255/281, 90.8%) groups. This affordable noninvasive POC test can be applied to identify individuals in the community most at risk of developing severe disease.

Positive Lymph Node Ratio as a new prognostic score in Geriatric patients with operated gastric cancer

ObjectiveThe pivotal prognostic determinant for recurrence and survival in surgically treated gastric cancer (GC) patients remains the lymph node status. Despite the adoption of D2 lymph node dissection as the standard approach in recent years, its association with increased morbidity in elderly patients raises concerns. This study aims to explore the prognostic significance of the Positive Lymph Node Ratio (PLNR) score in the context of recurrence and survival among elderly patients with surgically treated GC. Material and methodA retrospective review of files about surgically treated patients with GC was conducted. The prognostic impact of the PLNR score on overall survival (OS) was assessed through Receiver Operating Characteristic (ROC) analysis. ResultsThe cut-off value for the PLNR, determined through ROC analysis, was identified as 0.138. This value serves as a crucial threshold, as it distinguishes patients with a higher risk of poor outcomes. Patients with a PLNR score of 0.138 or below exhibited a median OS of 111 months, whereas those with a PLNR score above 0.138 had a significantly lower median OS of 22 months (p = 0.004). ConclusionOur findings revealed that the PLNR emerged as an independent predictor of survival and recurrence in patients undergoing GC resection.However, it's important to note that while valuable, the PLNR system has limitations. It does not encompass the T stage, a key factor in cancer staging. Therefore, it cannot be a direct substitute for the comprehensive information TNM staging provides. It should be used as a supplementary tool in predicting prognosis, particularly in elderly patients unsuitable for standard lymph node dissection.

Dynamic DeFi-G7 stock markets interactions and their potential role in diversifying and hedging strategies

AbstractThis study examines the link between stocks and decentralized finance (DeFi) in terms of returns and volatility. Major G7 exchange-traded funds (ETFs) and various highly traded DeFi assets are considered to ensure the robustness of the empirical experiment. Specifically, this study applies the vector autoregression generalized autoregressive conditional heteroskedasticity (VAR-GARCH) model to examine the information transmission of these two markets on a two-way basis and the dynamic conditional correlation (DCC)-GARCH model to assess the bivariate correlation structure between each DeFi and ETF pair. The volatility spillover analysis proves a contagion effect occurred between different geographic markets, and even between markets of different natures and typologies, during the most turbulent moments of the COVID-19 crisis and the war in the Ukraine. Our results also reveal a weak positive correlation between most DeFi and ETF pairs and positive hedge ratios that approach unity during turbulent times. In addition, DeFi assets, except for the Bazaar (BZR) Protocol, can offer diversification gains when included in financial investment portfolios. These results are particularly relevant for portfolio managers and policy-makers when designing investment strategies, especially during periods of financial crisis.

Correlation of Lymph Node Characteristics and Extranodal Extension in Oral Cavity Squamous Cell Carcinoma.

Identify correlations between lymph node characteristics and extranodal extension (ENE). Retrospective chart review. Tertiary care center. Patients who underwent neck dissection for oral cavity squamous cell carcinoma from 2004 to 2018 were included, with a starting sample of 496. The primary outcome was ENE in at least 1 lymph node. Additional variables included number of dissected nodes, positive nodes by level, positive lymph node ratio (LNR), and diameter of metastatic deposit and ENE focus. Univariate and multivariate binary logistic regression analyses were performed to determine correlations between included variables and ENE. Of the 496 patients, 233 had nodal metastasis (47.0%). 13,814 nodes were removed, with 714 (5.2%) containing metastasis. Of the positive nodes, 28.0% had ENE, 47.2% did not have ENE, and 24.8% were unknown. The mean ENE diameter was 5.1 mm (SD, 9.9). On univariate logistic regression analysis, ipsilateral neck LNR per 0.1 unit increase (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.02-1.32, P = .02), metastatic deposit size per 1 mm increase (OR 1.06, CI 1.04-1.08, P < .0001), and clinical T- (P = .02) and N-class (P = .0003) significantly correlated with ENE. On multivariate logistic regression analysis, size of metastatic deposit (OR 1.06, CI 1.03-1.08, P < .0001) remained significantly correlated with ENE. Controlling for confounding variables, size of metastatic deposit was an independent predictor of ENE, suggesting that as the metastatic deposit size increases, the odds of extension through the capsule also increases. This may be due to capsule thinning as the deposit grows or could represent the invasive nature of aggressive disease.

Enhancing Lymph Node Yield in Gastric Cancer Resection: Impact of Back Table Dissection on Number of Lymph Node Examined.

During gastric cancer resection, back table dissection (BTD) involves examination and separation of lymph node (LN) packets from the surgical specimen based on LN stations, which are sent to pathology as separately labeled specimens. With potential impact on clinical outcomes, we aimed to explore how BTD affects number of LNs examined. A retrospective review of a gastric cancer database was performed, including all cases of gastrectomy with D2 lymphadenectomy from January 2009 to March 2022. Back table dissection and conventional groups were compared using Mann-Whitney U and Fisher's exact tests. Multiple linear regression modeling was used to identify potential predictors of number of LN examined. A total of 174 patients were identified: 39 (22%) BTD and 135 (78%) conventional. More patients in the BTD group underwent neoadjuvant chemotherapy (62% vs 29%, P < .05). Compared to the conventional group, the BTD group had a greater number of LNs examined (42 [26-59] vs 21[15-33], median [IQR], P < .001), lower LN positivity ratio (.01 vs .07, P = .013), and greater number of LNs in patients with BMI >35 (32.5[27.5-39] vs 22[13-27], P = .041). A multiple linear regression model controlling for age, BMI, preoperative N stage, neoadjuvant chemotherapy, surgeon experience, and operative approach identified BTD as a significant positive predictor of number of LN examined (β = 19.7, P = .001). Back table dissection resulted in improved LN yield during gastric cancer resection. As a simple technical addition, BTD helps enhance pathology examination and improve surgeon awareness, which may ultimately translate to improve oncologic outcomes.

Evaluation of the use of additional capabilities of immunochemiluminescent analysis for determining the duration of infection with human immunodeficiency virus

Early assessment of HIV incidence is an important public health tool for understanding the state of the epidemic in a particular area, identifying high-risk groups, and assessing the effectiveness of HIV prevention interventions.Objective. To assess the possibility of using the positivity rate (S/CO) in the HIV Ag/Ab immunoassay on the Alinity i analytical platform to determine the duration of infection during HIV screening.Materials and methods. The study included 316 HIV-infected patients with different infection durations. Immunochemical analysis was performed on an Alinity i automatic analyzer (Abbott Laboratories, USA) using the Alinity i HIV Ag/Ab Reagent Kit (Abbott Laboratories, Germany) in accordance with the manufacturer’s instructions.Results. Statistical analysis of 316 blood samples from HIV-infected patients at different stages of infection demonstrated the reactivity of the Alinity i HIV Ag/Ab test result and a dynamic increase in the positivity ratio during the first six months after the onset of the disease. Based on the data obtained, a threshold value (≤294 conventional units) was obtained for the positivity ratio, which allowed for a clear distinction between HIV-positive patients with a recent (&lt;6 months) period of infection. At the same time, the sensitivity and specificity indicators for detecting recent infection in the CMIA analysis were 79,0% and 63,2%, respectively.Conclusion. The additional usage of the positivity ratio in the Alinity i HIV Ag/Ab CMIA analysis meets the acceptability criteria for assessing the duration of HIV infection and can be a useful tool for analyzing the stage of the epidemic in a particular territory.

Using ROC Analysis to Refine Cut Scores Following a Standard Setting Process

In educational assessment, cut scores are often defined through standard setting by a group of subject matter experts. This study aims to investigate the impact of several factors on classification accuracy using the receiver operating characteristic (ROC) analysis to provide statistical and theoretical evidence when the cut score needs to be refined. Factors examined in the study include the sample distribution relative to the cut score, prevalence of the positive event, and cost ratio. Forty item responses were simulated for examinees of four sample distributions. In addition, the prevalence and cost ratio between false negatives and false positives were manipulated to examine their impacts on classification accuracy. The optimal cut score is identified using the Youden Index J. The results showed that the optimal cut score identified by the evaluation criterion tended to pull the cut score closer to the mode of the proficiency distribution. In addition, depending on the prevalence of the positive event and cost ratio, the optimal cut score shifts accordingly. With the item parameters used to simulate the data and the simulated sample distributions, it was found that when passing the exam is a low-prevalence event in the population, increasing the cut score operationally improves the classification; when passing the exam is a high-prevalence event, then cut score should be reduced to achieve optimality. As the cost ratio increases, the optimal cut score suggested by the evaluation criterion decreases. In three out of the four sample distributions examined in this study, increasing the cut score enhanced the classification, irrespective of the cost ratio when the prevalence in the population is 50%. This study provides statistical evidence when the cut score needs to be refined for policy reasons.

Antioxidant and Pro-Oxidant Properties of Selected Clinically Applied Antibiotics: Therapeutic Insights.

The balance between antioxidants and pro-oxidants plays a significant role in the context of oxidative stress, influenced by both physiological and non-physiological factors. In this study, 18 prescribed antibiotics (including doxycycline hydrochloride, tigecycline, rifampicin, tebipenem, cefuroxime, cefixime, potassium clavulanate, colistin, ampicillin, amoxicillin, amikacin, nalidixic acid, azithromycin, pipemidic acid trihydrate, pivmecillinam, aztreonam, fosfomycin sodium, and ciprofloxacin) were subjected to simultaneous determination of antioxidant and pro-oxidant potential to assess if pro-oxidant activity is a dominant co-mechanism of antibacterial activity or if any antibiotic exhibits a balanced effect. This study presents a recently developed approach for the simultaneous assessment of antioxidant and pro-oxidant potential on a single microplate in situ, applied to prescribed antibiotics. Ten antibiotics from eighteen showed lower antioxidant or pro-oxidant potential, while five exhibited only mild potential with DPPH50 values over 0.5 mM. The pro-oxidant antioxidant balance index (PABI) was also calculated to determine whether antioxidant or pro-oxidant activity was dominant for each antibiotic. Surprisingly, three antibiotics-doxycycline hydrochloride, tigecycline, and rifampicin-showed significant measures of both antioxidant and pro-oxidant activities. Especially notable was tebipenem, a broad-spectrum, orally administered carbapenem, showed a positive PABI index ratio, indicating a dominant antioxidant over pro-oxidant effect. These findings could be significant for both therapy, where the antibacterial effect is enhanced by radical scavenging activity, and biotechnology, where substantial pro-oxidant activity might limit microbial viability in cultures and consequently affect yield.

Exploring leadership effectiveness and its impact on employee well-being through emotional mediation

PurposeThis study relied on the affective events theory to test the mediating role of the ratio of emotions in the relationship between employees' perceived leadership effectiveness and their well-being at work.Design/methodology/approachA quantitative methodology was used, based on a deductive approach of a transversal nature. Data were collected from a convenience sample consisting of 255 working adults.FindingsStructural equation modeling results demonstrated that perceived leadership effectiveness positively influenced well-being and the ratio of emotions, showing that when employees perceived their leader as effective, they tended to experience more positive emotions and less negative ones (as indicated by a positive ratio). Furthermore, the results supported the hypothesis that perceived leadership effectiveness influenced well-being through increases in the ratio of emotions.Research limitations/implicationsThe nature of the sample makes it impossible to generalize the results. Also, the fact that the questionnaires were self-reported may have biased the results because only the employees' perception of the variables under study was known.Practical implicationsThis study highlights the fact that perceived leadership effectiveness can be seen as an affective event that triggers positive and negative emotional responses at work, which, in turn, will have an impact on employee well-being.Originality/valueAn effective leadership style has been shown to be pivotal in reducing the prevalence of negative emotions within a team. When leaders foster a welcoming work environment where team members enjoy their roles, it often results in heightened positive emotions and overall well-being.