bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyzing the Asymptotic Behavior of an Extended SEIR Model with Vaccination for COVID-19
Authors: Papageorgiou Vasileios E. , Vasiliadis Georgios , Tsaklidis George
Published: December 2023

Several research papers have attempted to describe the dynamics of COVID-19 based on systems of differential equations. These systems have taken into account quarantined or isolated cases, vaccinations, control measures, and demographic parameters, presenting propositions regarding theoretical results that often investigate the asymptotic behavior of the system. In this paper, we discuss issues that concern the theoretical results proposed in the paper “An Extended SEIR Model with Vaccination for Forecasting the COVID-19 Pandemic in Saudi Arabia Using an Ensemble Kalman Filter”. We propose detailed explanations regarding the resolution of these issues. Additionally, this paper focuses on extending the local stability analysis of the disease-free equilibrium, as presented in the aforementioned paper, while emphasizing the derivation of theorems that validate the global stability of both epidemic equilibria. Emphasis is placed on the basic reproduction number R0, which determines the asymptotic behavior of the system. This index represents the expected number of secondary infections that are generated from an already infected case in a population where almost all individuals are susceptible. The derived propositions can inform health authorities about the long-term behavior of the phenomenon, potentially leading to more precise and efficient public measures. Finally, it is worth noting that the examined paper still presents an interesting epidemiological scheme, and the utilization of the Kalman filtering approach remains one of the state-of-the-art methods for modeling epidemic phenomena.
LASFormer: Light Transformer for Action Segmentation with Receptive Field-Guided Distillation and Action Relation Encoding
Authors: Ma Zhichao , Li Kan
Published: December 2023

Transformer-based models for action segmentation have achieved high frame-wise accuracy against challenging benchmarks. However, they rely on multiple decoders and self-attention blocks for informative representations, whose huge computing and memory costs remain an obstacle to handling long video sequences and practical deployment. To address these issues, we design a light transformer model for the action segmentation task, named LASFormer, with a novel encoder–decoder structure based on three key designs. First, we propose a receptive field-guided distillation to realize mode reduction, which can overcome more generally the gap in semantic feature structure between the intermediate features by aggregated temporal dilation convolution (ATDC). Second, we propose a simplified implicit attention to replace self-attention to avoid its quadratic complexity. Third, we design an efficient action relation encoding module embedded after the decoder, where the temporal graph reasoning introduces an inductive bias that adjacent frames are more likely to belong to the same class of model global temporal relations, and the cross-model fusion structure integrates frame-level and segment-level temporal clues, which can avoid over-segmentation independent of multiple decoders, thus reducing further computational complexity. Extensive experiments have verified the effectiveness and efficiency of the framework. Against the challenging 50Salads, GTEA, and Breakfast benchmarks, LASFormer significantly outperforms the current state-of-the-art methods in accuracy, edit score, and F1 score.
Necessary and Sufficient Conditions for Solvability of an Inverse Problem for Higher-Order Differential Operators
Authors: Bondarenko Natalia P.
Published: December 2023

We consider an inverse spectral problem that consists in the recovery of the differential expression coefficients for higher-order operators with separate boundary conditions from the spectral data (eigenvalues and weight numbers). This paper is focused on the principal issue of inverse spectral theory, namely, on the necessary and sufficient conditions for the solvability of the inverse problem. In the framework of the method of the spectral mappings, we consider the linear main equation of the inverse problem and prove the unique solvability of this equation in the self-adjoint case. The main result is obtained for the first-order system of the general form, which can be applied to higher-order differential operators with regular and distribution coefficients. From the theorem on the main equation’s solvability, we deduce the necessary and sufficient conditions for the spectral data for a class of arbitrary order differential operators with distribution coefficients. As a corollary of our general results, we obtain the characterization of the spectral data for the fourth-order differential equation in terms of asymptotics and simple structural properties.
Novel Formulas for B-Splines, Bernstein Basis Functions, and Special Numbers: Approach to Derivative and Functional Equations of Generating Functions
Authors: Simsek Yilmaz
Published: December 2023

The purpose of this article is to give relations among the uniform B-splines, the Bernstein basis functions, and certain families of special numbers and polynomials with the aid of the generating functions method. We derive a relation between generating functions for the uniform B-splines and generating functions for the Bernstein basis functions. We derive some functional equations for these generating functions. Using the higher-order partial derivative equations of these generating functions, we derive both the generalized de Boor recursion relation and the higher-order derivative formula of uniform B-splines in terms of Bernstein basis functions. Using the functional equations of these generating functions, we derive the relations among the Bernstein basis functions, the uniform B-splines, the Apostol-Bernoulli numbers and polynomials, the Aposto–Euler numbers and polynomials, the Eulerian numbers and polynomials, and the Stirling numbers. Applying the p-adic integrals to these polynomials, we derive many novel formulas. Furthermore, by applying the Laplace transformation to these generating functions, we derive infinite series representations for the uniform B-splines and the Bernstein basis functions.
p-Terphenyl and Diphenyl Ether Derivatives from the Marine-Derived Fungus Aspergillus candidus HM5-4
Authors: Zeng Yanbo , Wang Shirong , Peng Hanyang , Zhao Weibo , Chang Wenjun , Wang Hao , Chen Huiqin , Dai Haofu
Published: December 2023

Two undescribed p-terphenyl derivatives, asperterphenylcins A–B (1–2), and two undescribed diphenyl ether derivatives, asperdiphenylcins A–B (3–4), together with three previously described p-terphenyl derivatives—4″-deoxyterprenin (5), terphenyllin (6), and 3″-hydroxyterphenyllin (7)—were obtained from the solid-rice culture of the marine-derived fungus Aspergillus candidus HM5-4, which was isolated from sponges from the South China Sea. Their structures were elucidated by HRESIMS data and NMR spectroscopic analysis. Compound 1 showed a strong inhibitory effect on Neoscytalidium dimidiatum, with an inhibition circle diameter of 31.67 ± 2.36 mm at a concentration of 10.0 µg/disc. Compounds 5 and 7 displayed cytotoxic activity against human chronic myeloid leukemia cells (K562), human liver cancer cells (BEL-7402), human gastric cancer cells (SGC-7901), human non-small cell lung cancer cells (A549) and human HeLa cervical cancer cells, with IC50 values ranging from 3.32 to 60.36 µM, respectively. Compounds 2, 6 and 7 showed potent inhibitory activity against α-glucosidase, with IC50 values of 1.26 ± 0.19, 2.16 ± 0.44 and 13.22 ± 0.55 µM, respectively.
Effect of COVID-19 on Kidney Graft Function One Year after Onset
Authors: Malinowska Agnieszka , Ruszkowski Jakub , Muchlado Marta , Ślizień Zuzanna , Heleniak Zbigniew , Parczewska Aleksandra , Kanclerz Katarzyna , Biedunkiewicz Bogdan , Tylicki Leszek , Król Ewa , Dębska-Ślizień Alicja
Published: December 2023

Background and Objectives: Kidney transplant recipients (KTRs) are at a higher risk of severe COVID-19 development. The course of the infection may vary. Long-term consequences for graft function are still being studied. We investigate whether the clinical course of SARS-CoV-2 infection among KTRs had a long-term effect on graft function. Patients and method: 128 KTRs with confirmed SARS-CoV-2 infection were included in the study. They were divided into two groups: mild (without the need for oxygen therapy; n = 91) and severe (with the need for oxygen therapy; n = 21). Baseline characteristics and medical data, especially creatinine level, estimated glomerular filtration rate (eGFR) CKD-EPI, and proteinuria, were analyzed. The main outcomes were the absolute and relative change in eGFR during the one-year follow-up after COVID-19. In the final models, sex, age, smoking, presence of diabetes mellitus (DM), and cardiovascular disease (CVD) were included. Results: KTRs with severe COVID-19 were older, more likely to smoke, and had DM and CVD more frequently. Our analysis reveals that COVID-19 severity was associated with a significantly more pronounced relative eGFR decline one year after recovery only in males [−13.94 (95% CI: −25.13 to −2.76, p = 0.015) percentage points]. One year after the disease onset, males with a severe course of the infection had a higher eGFR decline than those with a mild one. The COVID-19 severity did not affect eGFR loss in females. Conclusions: In KTRs suffering from COVID-19, deterioration of graft function was noticed. The eGFR decline was associated with disease severity and sex. It indicates a need for further research, observation, and preventive actions for KTRs, especially males.
Combined Carbon Dioxide Laser with Photodynamic Therapy for Nodular Basal Cell Carcinoma Monitored by Reflectance Confocal Microscopy
Authors: Alma Antonio , Pongetti Linda , Clementi Alessandro , Chester Johanna , Toccaceli Matteo , Ciardo Silvana , Zappia Elena , Manfredini Marco , Pellacani Giovanni , Greco Maurizio , Bennardo Luigi , Farnetani Francesca
Published: December 2023

Introduction: Basal cell carcinoma (BCC) represents around 80% of all malignant skin cancers worldwide, constituting a substantial burden on healthcare systems. Due to excellent clearance rates (around 95%), surgery is the current gold-standard treatment. However, surgery is not always possible or preferred by patients. Numerous non-surgical therapies, sometimes combined, have been associated with promising tumor free survival rates (80–90%) in non-melanoma skin cancers (NMSCs). Most research has enrolled superficial basal cell carcinomas (sBCCs), with limited recent studies also involving low-risk nodular BCCs (nBCCs). Given lower efficacy rates compared to surgery, close monitoring during the follow-up period is essential for patients treated with non-surgical therapies. Monitoring with dermoscopy is constrained by low sensitivity rates. Reflectance confocal microscopy (RCM) is more sensitive in monitoring non-surgically treated NMSCs. Case presentation: A 41-year-old woman with a single nBCC relapse following photodynamic therapy (PDT) located on the dorsum of the nose presented to our center. Given the aesthetically sensitive location of the lesion and the patient’s preference for a non-surgical approach, a combined treatment of CO2 laser and PDT was prescribed. A superpulsed CO2 laser (power: 0.5–3 W, frequency: 10 Hz, spot size 2 mm) with two PDT sessions (2 weeks apart) were conducted. At 6 weeks follow-up, monitoring performed with RCM revealed a reduction but not eradication of basaloid tumor islands. Another 2 sessions of PDT were recommended. At 3, 12 and 30 months of follow-up, the nasal dorsum area of the previous nBBC lesion was noted to be slightly hypopigmented (observed clinically), with a mild erythematous background (observed by dermoscopy). RCM evaluation confirmed the absence of RCM BCC criteria. The cosmetic outcome was very much improved. Conclusions: Combined CO2 laser and PDT for the treatment of a localized nBCC on the dorsum of the nose of a 41-year-old proved to offer tumor free survival at 30-month follow-up, as monitored with RCM. RCM is useful for the evaluation of non-surgical therapies as it has comparably higher sensitivity than dermoscopy and is especially useful in cases of suspected late recurrence. Further studies are needed to validate ongoing tumor free survival following this combined nonsurgical approach in the treatment of nBCC.
A Review of Temperature Effects on Membrane Filtration
Authors: Xu Bochao , Gao Wa , Liao Baoqiang , Bai Hao , Qiao Yuhang , Turek Walter
Published: December 2023

Membrane technology plays a vital role in drinking water and wastewater treatments. Among a number of factors affecting membrane performance, temperature is one of the dominant factors determining membrane performance. In this review, the impact of temperature on membrane structure, fouling, chemical cleaning, and membrane performance is reviewed and discussed with a particular focus on cold temperature effects. The findings from the literature suggest that cold temperatures have detrimental impacts on membrane structure, fouling, and chemical cleaning, and thus could negatively affect membrane filtration operations and performance, while warm and hot temperatures might expand membrane pores, increase membrane flux, improve membrane chemical cleaning efficiency, and interfere with biological processes in membrane bioreactors. The research gaps, challenges, and directions of temperature effects are identified and discussed indepth. Future studies focusing on the impact of temperature on membrane processes used in water and wastewater treatment and the development of methods that could reduce the adverse effect of temperature on membrane operations are needed.
Comparison of Anion-Exchange Membranes for Diffusion Dialysis of Mixtures of Acids and Their Iron Salts
Authors: Bendová Helena , Dušek Libor , Palarčík Jiří
Published: December 2023

This study presents the possibility of using diffusion dialysis for the separation of inorganic acids (hydrochloric, nitric, and hydrofluoric) and their ferric salts whose composition corresponds to that of real spent pickling solutions. At a steady state, the transport properties of three different anion-exchange membranes (Fumasep-FAD, Neosepta-AFN, and Neosepta-AHA) are compared using a continuous counter-current dialyzer. At a constant composition of the solutions (acid concentration 3 mol L−1 and iron concentration 30–40 g L−1), the effects of volumetric liquid flow rates on the transport rate of H+ and Fe3+ ions through the membrane are studied. The dialysis process is characterized by the recovery of acids and the rejection of salts. Furthermore, the values of the dialysis coefficients of acids, iron, and the acid/iron separation factors are calculated and compared. The volumetric flow rates of the inlet streams change in limits from 3 × 10−8 to 6 × 10−8 m3 s−1 (from 3 to 6 L h−1 m−2, relative to the membrane area). A comparison of the tested membranes shows slightly better results for acid recovery, iron rejection, and acid/iron separation factors for the Fumasep-FAD membrane than for the Neosepta-AFN membrane. However, the results obtained show that both of these anion-exchange membranes can be considered good separators for tested mixtures that simulate real spent pickling solutions, and there is a good precondition for using diffusion dialysis for processing these solutions in industrial practice. On the contrary, very low values of acid recovery and the overall dialysis coefficient of acid are found for the Neosepta-AHA membrane in the test range of the volumetric flow rate, and, thus, this membrane is insufficient for the adequate separation of these acids and iron salts.
Lipid Metabolism in Metabolic-Associated Steatotic Liver Disease (MASLD)
Authors: Syed-Abdul Majid Mufaqam
Published: December 2023

Metabolic-associated steatotic liver disease (MASLD) is a cluster of pathological conditions primarily developed due to the accumulation of ectopic fat in the hepatocytes. During the severe form of the disease, i.e., metabolic-associated steatohepatitis (MASH), accumulated lipids promote lipotoxicity, resulting in cellular inflammation, oxidative stress, and hepatocellular ballooning. If left untreated, the advanced form of the disease progresses to fibrosis of the tissue, resulting in irreversible hepatic cirrhosis or the development of hepatocellular carcinoma. Although numerous mechanisms have been identified as significant contributors to the development and advancement of MASLD, altered lipid metabolism continues to stand out as a major factor contributing to the disease. This paper briefly discusses the dysregulation in lipid metabolism during various stages of MASLD.
Combined Activity of Saponin B Isolated from Dodonaea viscosa Seeds with Pesticide Azadirachtin against the Pest Spodoptera litura
Authors: Yu Hang , Liu Boyu , Zhao Yuhan , Li Jinliang , Wu Guoxing , Ma Junhong , Gui Furong , Tao Feng , Hao Xiaojiang , Ding Xiao , Qin Xiaoping
Published: December 2023

Azadirachtin is regarded as one of the best botanical pesticides due to its broad spectrum of insecticides and low interference with natural enemies. To enhance the effect of azadirachtin and slow down the generation of resistance, the combined activity was studied. Here, we found that Dodonaea viscosa saponin B (DVSB) isolated from the seeds of Dodonaea viscosa has good combined activity with the azadirachtin. The mixture of DVSB and azadirachtin in a volume ratio of 1:4 had the strongest combined effect against Spodoptera litura, with a co-toxicity coefficient (CTC) of 212.87. DVSB exerted its combined activity by affecting the contact angle, surface tension, maximum retention and cell membrane permeability. When mixed with DVSB, the contact angle and surface tension decreased by 30.38% and 23.68%, and the maximum retention increased by 77.15%. DVSB was screened as an effective combined activity botanical compound of azadirachtin upon the control of S. litura and highlights the potential application of botanical compounds as pesticide adjuvants in the pest management.
A Real-Time Defect Detection Strategy for Additive Manufacturing Processes Based on Deep Learning and Machine Vision Technologies
Authors: Wang Wei , Wang Peiren , Zhang Hanzhong , Chen Xiaoyi , Wang Guoqi , Lu Yang , Chen Min , Liu Haiyun , Li Ji
Published: December 2023

Nowadays, additive manufacturing (AM) is advanced to deliver high-value end-use products rather than individual components. This evolution necessitates integrating multiple manufacturing processes to implement multi-material processing, much more complex structures, and the realization of end-user functionality. One significant product category that benefits from such advanced AM technologies is 3D microelectronics. However, the complexity of the entire manufacturing procedure and the various microstructures of 3D microelectronic products significantly intensified the risk of product failure due to fabrication defects. To respond to this challenge, this work presents a defect detection technology based on deep learning and machine vision for real-time monitoring of the AM fabrication process. We have proposed an enhanced YOLOv8 algorithm to train a defect detection model capable of identifying and evaluating defect images. To assess the feasibility of our approach, we took the extrusion 3D printing process as an application object and tailored a dataset comprising a total of 3550 images across four typical defect categories. Test results demonstrated that the improved YOLOv8 model achieved an impressive mean average precision (mAP50) of 91.7% at a frame rate of 71.9 frames per second.
Evaluation of Concrete Carbonation Based on a Fiber Bragg Grating Sensor
Authors: Li Jianzhi , Yang Haiqun , Wu Handong
Published: December 2023

The carbonation of concrete greatly affects its service life. In this paper, fiber Bragg grating (FBG) sensors were used to investigate the relationship between concrete carbonation and its mechanical properties. A T130 High Sensitivity Strain Cable Sensor with a good linearity was used to monitor the internal strain in concrete, to investigate the variation in the elastic modulus of concrete with carbonation time. A mathematical model of elastic modulus and carbonation time of concrete based on FBG was established. At the same time, the authors explored the relationship between the carbonation depth and compressive strength of concrete and the carbonation time using a phenolphthalein solution test and a compressive strength test, respectively. The experimental results indicate that the carbonation depth, compressive strength, and elastic modulus of concrete increase with carbonation time. In the early stage of carbonation, these three parameters increase rapidly, while they grow slowly in the later stage of carbonation. The varying trend of the elastic modulus of concrete is consistent with the compressive strength, which shows a binomial relationship. Therefore, the elastic modulus, measured using FBG sensors, is used as an indicator of the characterization of the carbonation resistance of concrete. This work provides a new approach for concrete carbonation detection and assessment.
Amine-Impregnated Dendritic Mesoporous Silica for the Adsorption of Formaldehyde
Authors: Lee Ji Myeong , Kang Misun , Kim June-Seo , Bae Jae Young
Published: December 2023

To adsorb and remove formaldehyde, which is a harmful volatile organic chemical (VOC) detected indoors, an alkylamine was introduced into the substrate as a formaldehyde adsorbent. In this study, Tetraethylenepentaamine (TEPA) was introduced into the mesoporous silica using the amine impregnation method. Since the impregnated alkylamine can block the pores of the silica substrate, the pore size and pore volume are very important factors for its use as a substrate for an adsorbent. Focusing on the substrate’s pore properties, Santa Barbara Amorphous-15 (SBA-15) was chosen as a conventional one-dimensional pore-structured mesoporous silica, and dendritic mesoporous silica (DMS) as a three-dimensional pore-structured mesoporous silica. To 1 g each of silica substrate DMS and SBA-15, 0, 0.5, 1.5, and 2.5 g of TEPA were introduced. A fixed concentration and amount of formaldehyde gas was flowed through the adsorbent and then the adsorbent was changed to the 2,4-Dinitrophenylhydrazine (2,4-DNPH) cartridge to adsorb the remaining formaldehyde. According to the methods recommended by the World Health Organization (WHO) and National Institute for Occupational Safety & Health (NIOSH), the formaldehyde captured by 2,4-DNPH was analyzed using high-performance liquid chromatography (HPLC). A comparison of DMS and SBA-15 in the amine impregnation method shows that not only surface area, but also large pore size and high pore volume, contribute to the formaldehyde adsorption ability.
Design and Implementation of a Power Semiconductor-Based Switching Mode Laser Diode Driver
Authors: Ma Chao-Tsung , Zhang Fang-Yu
Published: December 2023

Fiber lasers are commonly used in many industrial applications, such as cutting, welding, marking, and additive manufacturing. In a fiber laser system, the driver of a pumping source using a laser diode (LD) module and its dynamic control capability directly affect the performance of the fiber laser system. The commercial design of pumping source drivers for high-power fiber lasers is mainly based on a linear-type DC power supply, which has two major drawbacks, i.e., lower efficiency and bulk. In this regard, this paper proposes for the first time a new design approach with a programmable switching mode laser diode driver using a power semiconductor device (PSD)-based full-bridge phase-shifted (FB-PS) DC-DC converter for driving a 200 W optical power laser diode module. In this paper, the characteristics of a laser diode module and the system configuration of the proposed laser diode driver are first introduced. Then, a current control scheme using the concept of phase angle shifting to achieve a fast dynamic current tracking feature is explained. The proposed current control technique with a fully digital control scheme is then addressed. Next, dynamic mathematical models of the laser diode driver system and controllers are derived, and the quantitative design detail of the controller is presented. To confirm the correctness of the proposed control scheme, a simulation study on a typical control case is performed in PSIM 9.1 software environment. To verify the effectiveness of the proposed LD driver, a digital signal processor is then used as the control core to construct a hardware prototype implementation for performing experimental tests. Results obtained from simulation and hardware tests show highly satisfactory driving performances in the laser diode’s output current command tracking control.
A Two-Dimensional Computer-Aided Design Study of Unclamped Inductive Switching in an Improved 4H-SiC VDMOSFET
Authors: Nie Xinfeng , Wang Ying , Yu Chenghao , Fei Xinxing , Yang Jianqun , Li Xingji
Published: December 2023

Due to its high thermal conductivity, high critical breakdown electric field, and high power, the silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) has been generally used in industry. In industrial applications, a common reliability problem in SiC MOSFET is avalanche failure. For applications in an avalanche environment, an improved, vertical, double-diffused MOSFET (VDMOSFET) device has been proposed. In this article, an unclamped inductive switching (UIS) test circuit has been built using the Mixed-Mode simulator in the TCAD simulation software, and the simulation results for UIS are introduced for a proposed SiC-power VDMOSFET by using Sentaurus TCAD simulation software. The simulation results imply that the improved VDMOSFET has realized a better UIS performance compared with the conventional VDMOSFET with a buffer layer (B-VDMOSFET) in the same conditions. Meanwhile, at room temperature, the modified VDMOSFET has a smaller on-resistance (Ron,sp) than B-VDMOSFET. This study can provide a reference for SiC VDMOSFET in scenarios which have high avalanche reliability requirements.
Ultrathin Flexible Encapsulation Materials Based on Al2O3/Alucone Nanolaminates for Improved Electrical Stability of Silicon Nanomembrane-Based MOS Capacitors
Authors: Wang Zhuofan , Lu Hongliang , Zhang Yuming , Liu Chen , Zhang Haonan , Yu Yanhao
Published: December 2023

Ultrathin flexible encapsulation (UFE) using multilayered films has prospects for practical applications, such as implantable and wearable electronics. However, existing investigations of the effect of mechanical bending strains on electrical properties after the encapsulation procedure provide insufficient information for improving the electrical stability of ultrathin silicon nanomembrane (Si NM)-based metal oxide semiconductor capacitors (MOSCAPs). Here, we used atomic layer deposition and molecular layer deposition to generate 3.5 dyads of alternating 11 nm Al2O3 and 3.5 nm aluminum alkoxide (alucone) nanolaminates on flexible Si NM-based MOSCAPs. Moreover, we bent the MOSCAPs inwardly to radii of 85 and 110.5 mm and outwardly to radii of 77.5 and 38.5 mm. Subsequently, we tested the unbent and bent MOSCAPs to determine the effect of strain on various electrical parameters, namely the maximum capacitance, minimum capacitance, gate leakage current density, hysteresis voltage, effective oxide charge, oxide trapped charge, interface trap density, and frequency dispersion. The comparison of encapsulated and unencapsulated MOSCAPs on these critical parameters at bending strains indicated that Al2O3/alucone nanolaminates stabilized the electrical and interfacial characteristics of the Si NM-based MOSCAPs. These results highlight that ultrathin Al2O3/alucone nanolaminates are promising encapsulation materials for prolonging the operational lifetimes of flexible Si NM-based metal oxide semiconductor field-effect transistors.
Assess the Diagnostic Accuracy of GeneXpert to Detect Mycobacterium tuberculosis and Rifampicin-Resistant Tuberculosis among Presumptive Tuberculosis and Presumptive Drug Resistant Tuberculosis Patients
Authors: Ramachandra Venkateswari , Brammacharry Usharani , Muralidhar Aaina , Muthukumar Anbazhagi , Mani Revathi , Muthaiah Muthuraj , Soundappan Govindarajan , Frederick Asha
Published: December 2023

GeneXpert MTB/RIF is a rapid molecular diagnostic tool capable of simultaneously detecting Mycobacterium tuberculosis and rifampicin resistance. This study aimed to assess the diagnostic precision of GeneXpert MTB/RIF assay to detect pulmonary and extrapulmonary tuberculosis and evaluate the performance for detecting of rifampicin resistance. Of 37,695 samples, 7156 (18.98%) were tuberculosis-positive, and 509 (7.11%) were rifampicin-resistant. The sensitivity, specificity, positive predictive value, negative predictive value, disease prevalence, and accuracy of the GeneXpert MTB/RIF assay for pulmonary tuberculosis were 99.87% (95%CI: 99.75–99.94), 99.92% (95%CI: 99.88–99.95), 99.71% (95%CI: 99.54–99.82), 99.97% (95%CI: 99.93–99.98), 21.38% (95%CI: 20.92–21.86), and 99.91% (95%CI: 99.87–99.94), respectively. For extrapulmonary tuberculosis, the sensitivity, specificity, PPV, NPV, disease prevalence, and accuracy of GeneXpert MTB/RIF assay accounted for 99.45% (95%CI: 98.73–99.82), 99.84% (95%CI: 99.73–99.92), 98.70% (95%CI: 97.73–99.25), 99.93% (95%CI: 99.84–99.97), 10.64% (95%CI: 9.99–11.31), and 99.80% (95%CI: 99.68–99.88), respectively. Despite its high sensitivity for detecting tuberculosis and rifampicin resistance, GeneXpert MTB/RIF had contradictory results for 20.5% of cases among patients with smear-negative results and 54.9% of cases among patients with a high risk of multidrug-resistant tuberculosis. Of 46% fluoroquinolone-resistant cases, 16.56% (26/157) were multidrug-resistant tuberculosis isolates, and 4.02% (20/498) were isoniazid-resistant, a characteristic distribution leading to about 17.2% of fluoroquinolone-resistance events and relevant marker gyr-A mutations in MDR tuberculosis isolates. Further, our study indicated that increased fluoroquinolone resistance among rifampicin-resistant and isoniazid-resistant tuberculosis endangers the success of newly endorsed MDR-TB regimens.
Gastrointestinal and Hepatological Manifestations in Severe Acute Respiratory Syndrome Coronavirus 2 Infection: Results from the Major COVID Hospital in Serbia
Authors: Mijac Dragana , Vucelj Samir , Todorovic Kristina , Vojnovic Marko , Milicic Biljana , Lukic Snezana , Filipovic Branka , Marjanovic Haljilji Marija , Popovic Dusan , Adzic Vukicevic Tatjana
Published: December 2023

The coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), includes a clinical spectrum of diseases from mild to severe progressive pneumonia, which has affected and still affects the human population worldwide. Most commonly, it is presented by respiratory symptoms, but studies have shown that about 50% of patients with SARS-CoV-2 infection have at least one gastrointestinal symptom (GI), predominantly nausea, diarrhea, vomiting, or loss of appetite. In addition, abnormal liver functional tests are commonly present in the SARS-CoV-2 virus. The aim of our study was to examine the GI and hepatic manifestations of COVID-19 in patients hospitalized due to COVID-19 pneumonia in “COVID hospital Batajnica”, University Clinical Center of Serbia in Belgrade. The study included 498 consecutive patients, and the data was obtained from the patient’s electronic medical history. GI symptoms included nausea, vomiting, diarrhea, and anorexia. Collected laboratory values included baseline and peak values of blood count, inflammatory parameters, liver function tests, renal function tests, and cardiac enzyme tests. The results have shown that GI symptoms occurred in 26% of cases at diagnosis, which indicates the great susceptibility of the GI system to SARS-CoV-2. There was a high risk of liver injury in patients with COVID-19 pneumonia (>60%). The level of AST is more often increased compared to ALT, which is different from other virus-induced liver lesions and may be a useful indicator of SARS-CoV-2 infection. Further research should focus on the causes of liver damage in SARS-CoV-2 virus and the impact on treatment and outcome of COVID-19 disease.
Advances in Campylobacter: Molecular Epidemiology, Virulence Factors, Immune Responses and Drug Resistance
Authors: Zautner Andreas E.
Published: December 2023

Campylobacter infections, caused by Campylobacter jejuni and Campylobacter coli, are a major global concern, particularly as they are the leading cause of bacterial enteritis [...]
Viruses of Plankton: On the Edge of the Viral Frontier
Authors: Mojica Kristina D. A. , Brussaard Corina P. D.
Published: December 2023

The field of aquatic viral ecology has continued to evolve rapidly over the last three decades [...]
Nasopharyngeal Bacterial Prevalence and Microbial Diversity at First Treatment for Bovine Respiratory Disease (BRD) and Its Associations with Health and Mortality Outcomes in Feedyard Cattle
Authors: Neal Kyndall , Amachawadi Raghavendra G. , White Brad J. , Shippy Teresa D. , Theurer Miles E. , Larson Robert L. , Lubbers Brian V. , Kleinhenz Michael
Published: December 2023

Bovine respiratory disease (BRD) is an economically important disease in feedyards influencing both animal welfare and antimicrobial utilization. Major pathogens associated with BRD have been identified in previous research, but little information is available on the relationship between nasopharyngeal microbiota and health outcomes. The objective of this study was to identify potential associations between nasopharyngeal microbiota and antimicrobial resistance patterns of clinical cases that lived or died compared to non-diseased controls. Enrolled animals were subdivided based on clinical disease status and case outcome (subsequent mortality). Deep nasopharyngeal swabs were collected on enrolled animals and submitted for bacterial isolation, antimicrobial susceptibility determination, and metagenomics analysis. Enrolled cattle were represented in three groups: animals at first treatment for BRD that subsequently died (BRDM, n = 9), animals at first treatment for BRD that subsequently lived (BRDL, n = 15), and animals that were never treated for BRD during the feeding phase (CONT, n = 11). Antimicrobial resistance patterns for Pasteurella multocida illustrated cattle in each outcome category had isolates that were pan-susceptible or only showed resistance to oxytetracycline. The relative abundance of species and genera illustrated few differences among the three outcomes. Higher alpha diversity was identified in BRDL compared to CONT at the species level, and both BRDL and BRDM showed increased alpha diversity compared to CONT at the general level. Overall, this work illustrated nasopharyngeal microbiota showed relatively few differences among BRD cases that lived or died compared to animals without BRD.
Kenya’s Mineral Landscape: A Review of the Mining Status and Potential Recovery of Strategic and Critical Metals through Hydrometallurgical and Flotation Techniques
Authors: Kiprono Nelson R. , Smoliński Tomasz , Rogowski Marcin , Herdzik-Koniecko Irena , Sudlitz Marcin , Chmielewski Andrzej G.
Published: December 2023

Kenya is an East African country with the third-largest economy in sub-Saharan Africa. The demand for metals and minerals continues to increase due to urbanization, population rise, and new infrastructure growth in different countries. Kenya formally confirmed the discovery of oil and various minerals in April 2013, launching itself as a new player in Africa’s rapidly expanding extractive sector. This review paper highlights the mining status in Kenya and the role of hydrometallurgical and flotation processes in the recovery of deficit metals from ores and mine wastes. The nation’s 2030 Vision is anticipated to benefit greatly from the proceeds from the sale of oil, gas, and valuable metals. Because Kenya was originally mapped as an agricultural region, less mineral prospecting was done in earlier times. The country’s mining industry is now dominated by the manufacture of non-metallic goods, and it is largely neglected for minerals. One of the most serious problems for the mining industry in Kenya is the production of tailings that hold strategic metals. The material is already ground, which means the most energy-consuming process has been already applied, and chemical engineering processes like leaching are more feasible at this point. Hydrometallurgical and flotation recovery of valuable metals from wastes, high and low-grade ores, or tailings is essential. The resources will be preserved, which ensures sustainability in the growth of the mining industry.
Complex-Forming Properties of the Anti-Inflammatory Sialorphin Derivative Palmitic Acid-Lysine-Lysine-Glutamine-Histidine-Asparagine-Proline-Arginine with Cu(II) Ions in an Aqueous Solution
Authors: Pająk Marek , Kamysz Elżbieta , Sikora Karol , Fichna Jakub , Woźniczka Magdalena
Published: December 2023

The present work describes the complexation of the anti-inflammatory sialorphin derivative Pal-Lys-Lys-Gln-His-Asn-Pro-Arg (palmitic acid-lysine-lysine-glutamine-histidine-asparagine-proline-arginine) with Cu(II) ions in an aqueous solution, at a temperature of 25.0 ± 0.1 °C, over the whole pH range. The complexing properties were characterized by potentiometric and UV-Vis spectrophotometric methods. The potentiometric method was used to calculate the logarithms of the overall stability constants (log β) and the values of the stepwise dissociation constants (pKa) of the studied complexes. The percentage of each species formed in an aqueous solution was estimated from the species distribution curve as a function of pH. The absorbance (A) and molar absorption coefficient (ε) values for the Cu(II)-sialorphin derivative system were determined with UV-Vis spectroscopy. Our studies indicate that the sialorphin derivative forms stable complexes with Cu(II) ions, which may lead to future biological and therapeutic applications.
A Convenient Synthesis of Novel Isoxazolidine and Isoxazole Isoquinolinones Fused Hybrids
Authors: Ouzounthanasis Konstantinos A. , Rizos Stergios R. , Koumbis Alexandros E.
Published: December 2023

Isoxazolidine, isoxazole, and isoquinolinone rings are present in the structure of several natural products and/or pharmaceutically interesting compounds. In this work, facile and efficient pathways have been developed for the preparation of fused frameworks bearing those heterocycles. The successful approaches for both isoxazolidine/isoquinolinone and isoxazole/isoquinolinone hybrid syntheses relied initially on 1,3-dipolar cycloadditions of nitrones and nitrile oxides to indenone and 2-propargylbenzamide, respectively. The construction of the isoquinolinone lactam system followed by performing a selective Schmidt reaction for isoxazolidine derivatives (two steps overall), whereas the isoxazole lactams were reached via an Ullmann-type cyclisation (three steps overall). Key observations were made regarding the stereo- and regioselectivities of the reactions employed, and small libraries of the targeted hybrids were prepared, demonstrating the general applicability of these strategies.
Phase Separation of Br-Doped CsPbI3: A Combined Cluster Expansion, Monte Carlo, and DFT Study
Authors: Maleka Prettier , Dima Ratshilumela , Tshwane David , Ntwaeaborwa Odireleng , Maphanga Rapela
Published: December 2023

Cluster expansion, which is a method that describes the concentration-dependent thermodynamic properties of materials while maintaining density functional theory accuracy, was used to predict new (CsPbIxBr1−x) structures. The cluster-expansion method generated 42 new stable (CsPb)xIyBrz (where x = 1 to 3 and y and z = 1 to 8) structures and these were ranked as meta-stable structures based on their enthalpies of formation. Monte Carlo calculations showed that CsPbI0.5Br0.5 composition separates into different phases at 300 K, but changes to a homogeneous phase at 700 K, suggesting that a different phase of CsPbI3 may exist at higher temperatures. Among the 42 predicted structures, randomly selected structures around iodide-rich, 50:50, and bromine-rich sites were studied further by determining their electronic, optical, mechanical, and thermodynamic properties using first-principle density functional theory. The materials possess similar properties as cubic Br-doped CsPbI3 perovskites. The mechanical properties of these compounds revealed that they are ductile in nature and mechanically stable. This work suggests that the introduction of impurities into CsPbI3 perovskite materials, as well as compositional engineering, can alter the electronic and optical properties, making them potential candidates for solar cell applications.
Innovative Detection of Testosterone Esters in Camel Hair: Unravelling the Mysteries of Dromedary Endocrinology
Authors: Shah Iltaf , Hakeem Muhammad K. , Alraeesi Aysha , Barker James
Published: December 2023

Introduction: Doping and steroid use represent a serious threat to animal health and can even lead to their untimely and painful death. However, doping is an acute problem in today’s animal racing world, particularly in camel racing. Testosterone and its ten esters (benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate, laurate, enanthate, cypionate, and caproate) are of utmost importance, because when they are administered to animals it is difficult to measure them efficiently. The levels of testosterone and its esters in camels and other animals are typically determined using urine and blood tests. The aim of this study was to develop and validate a liquid chromatographic–mass spectrometric (LC-MS/MS) method to determine testosterone esters in camel hair, and to apply the validated method to determine testosterone esters in collected samples. To our knowledge, this is the first report of such research. Results and Discussion: The levels of testosterone and its ten derivatives, along with the cortisol-D4 internal standard, were optimised for LC–MS/MS analysis; however, only testosterone along with its seven esters (namely benzoate, valerate, isocaproate, hexahydrobenzoate, decanoate, undecanoate and laurate) could be validated in camel hair. Only five testosterone esters could be determined in camel hair samples; the concentrations were obtained as 10.5–14.9 pg/mg for valerate (in three camels), 12.5–151.6 pg/mg for hexahydrobenzoate (in six camels), 4.8–32.1 pg/mg for laurate (in five camels), 5.1 pg/mg decanoate (in one camel), and 8.35–169 pg/mg for testosterone (in all 24 camels). Interestingly, the three racing camels displayed high concentrations of testosterone (59.2–169 pg/mg, all three camels), laurate (4.8–14.5 pg/mg, two camels), hexahydrobenzoate (116 pg/mg, one camel), decanoate (5.1 pg/mg, one camel), and valerate (11.7 pg/mg, one camel). Methods: Camel hair samples were collected from 21 non-racing dromedary camels along with three racing camels in Al Ain, UAE; these were decontaminated, pulverised, sonicated, and extracted prior to analysis. An LC–MS/MS method was employed to determine the levels of testosterone esters in the hair samples. Conclusions: This novel camel-hair test procedure is accurate, sensitive, rapid, and robust. The findings reported in this study could be significant to evaluate racing camels for suspected doping offenses. Further controlled testosterone supplementation studies are required to evaluate individual esters’ effects on camel health and diseases and on performance enhancement levels. This new hair test could promote further studies in doping control, toxicology, and pharmacology, as well as having other clinical applications relating to camel health, injury, and disease.
Bioaccumulation Capacity of Onion (Allium cepa L.) Tested with Heavy Metals in Biofortification
Authors: Czarnek Katarzyna , Tatarczak-Michalewska Małgorzata , Szopa Agnieszka , Klimek-Szczykutowicz Marta , Jafernik Karolina , Majerek Dariusz , Blicharska Eliza
Published: December 2023

On a worldwide scale, A. cepa is among the most commonly consumed vegetables. In Europe, the leading onion producers are Russia, the Netherlands, Spain, Poland and Germany. In this study, the bioaccumulation of heavy metals (Cr, Cu, Zn, Ni, Fe, Mn, Co, Sr, Cd and Pb) by Allium cepa L. plants was followed under hydroponic conditions. The heavy metals were applied at six concentrations (0, 25, 50, 100, 200 and 400 mg L−1) over three weeks. The quantitative analysis of selected heavy metals in plant tissues (bulbs, roots and assimilation leaves) was performed using atomic absorption spectrometry with flame atomization (F-AAS). The accumulation of metal ions was strongly dependent on their concentrations in the solution and the analyzed parts of plants. The highest accumulation of metal ions was confirmed for the roots and ranged from 8.48 to 5912.34 µg g−1 DW (dry weight). All parts of A. cepa were characterized by the high accumulation of Mn2+. The lowest accumulation was confirmed for Co2+ in the roots, Pb2+ in the assimilation leaves and Cu2+ in the bulbs of onion. Moreover, the study showed that the highest concentrations of heavy metals decreased the growth of bulbs and even caused them to die off. In contrast, lower concentrations of some elements stimulated plant development.
Relating Paramagnetic Properties to Molecular Parameters of Humic Acids Isolated from Permafrost Peatlands in the European Arctic
Authors: Lodygin Evgeny , Vasilevich Roman , Abakumov Evgeny
Published: December 2023

Free radicals (FRs) are intermediate participants in the transformation process of soil organic matter, and free radical activity is a fundamental property of humic substances. The aim of this work was to conduct a comparative study of the paramagnetic properties of humic acids (HAs) isolated from Histosols by electron paramagnetic resonance (EPR) spectroscopy. The studied Histosols are found in permafrost peatlands in four natural geographic subzones of the European Arctic (from forest tundra to northern tundra). The results obtained showed that in anaerobic conditions on the peatlands in the tundra zone, the formation of semiquinone-type radicals occurs through the reduction of quinone fragments of HAs and leads to an increase in the concentration of paramagnetic centres within HAs. PCA analysis allowed us to reveal relationships between the properties of the initial raw peat samples, the molecular composition of the isolated HAs, and their paramagnetic parameters. It was found that FR localization occurs predominantly on aromatic fragments of lignin nature, which are confined to the low molecular weight fraction of HAs. The g-factor values of the EPR spectra of HAs indicate the presence of carbon- and oxygen-centred FRs in the HA structure, with a predominance of the latter.
Unpacking Phthalates from Obscurity in the Environment
Authors: Baneshi Marzieh , Tonney-Gagne Jamey , Halilu Fatima , Pilavangan Kavya , Sabu Abraham Ben , Prosser Ava , Kanchanadevi Marimuthu Nikaran , Kaliaperumal Rajendran , Britten Allen J. , Mkandawire Martin
Published: December 2023

Phthalates (PAEs) are a group of synthetic esters of phthalic acid compounds mostly used as plasticizers in plastic materials but are widely applied in most industries and products. As plasticizers in plastic materials, they are not chemically bound to the polymeric matrix and easily leach out. Logically, PAEs should be prevalent in the environment, but their prevalence, transport, fate, and effects have been largely unknown until recently. This has been attributed, inter alia, to a lack of standardized analytical procedures for identifying them in complex matrices. Nevertheless, current advancements in analytical techniques facilitate the understanding of PAEs in the environment. It is now known that they can potentially impact ecological and human health adversely, leading to their categorization as endocrine-disrupting chemicals, carcinogenic, and liver- and kidney-failure-causing agents, which has landed them among contaminants of emerging concern (CECs). Thus, this review article reports and discusses the developments and advancements in PAEs’ standard analytical methods, facilitating their emergence from obscurity. It further explores the opportunities, challenges, and limits of their advancements.