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In this study, a complete model for a miniature excitation-powered piezoelectric generator (PG), analysis modes of operation and control of a full-bridge joule thief (FBRJT) circuit to identify the optimal points were investigated. The proposed model revealed the PG's power dependency on mechanical excitation, acceleration, and frequency and defined the load behaviour for power optimisation. The proposed circuit, namely FBRJT, was integrated with the conventional full-bridge rectifier (FBR) in Stage 1 for AC-DC conversion and with the joule thief circuit in Stage 2 for DC-DC conversion. This integration acted as a boost converter without utilising the duty cycles and additional switching components. The electrical nature of the input of FBRJT with a simple structure, sensor-less control and auxiliary circuits showed a consistent agreement with the investigated testing scenarios using both ideal and impedance power sources. Additionally, the performance of the proposed circuit was also verified against the published results of power electronics circuits. The developed versatile circuit and control system can be utilised for many applications, such as mobile battery charging and energy harvesting. [ABSTRACT FROM AUTHOR]

The present paper deals with the investigations of a Kenmotsu manifold satisfying certain curvature conditions endowed with - η -Ricci solitons. First we find some necessary conditions for such a manifold to be φ -Einstein. Then, we study the notion of - η -Ricci soliton on this manifold and prove some significant results related to this notion. Finally, we construct a nontrivial example of three-dimensional Kenmotsu manifolds to verify some of our results. [ABSTRACT FROM AUTHOR]

In this paper, we characterize three-dimensional Riemannian manifolds M 3 admitting Ricci–Yamabe solitons (RYSs). It is proved that if an M 3 endowed with a semi-symmetric metric ζ -connection admits an RYS, then the scalar curvature of M 3 satisfies the Poisson equation Δ r = 8 (2 α − 3 β − ϱ) β , where α , β ∈ ℝ and β ≠ 0. We also discuss the existence of gradient RYS in Riemannian setting. Finally, we construct a nontrivial example of three-dimensional Riemannian 3-manifolds admitting RYS to prove some of our results. [ABSTRACT FROM AUTHOR]

In the present paper, we characterize m-dimensional ζ -conformally flat L P -Kenmotsu manifolds (briefly, (L P K) m ) equipped with the Ricci–Yamabe solitons (RYS) and gradient Ricci–Yamabe solitons (GRYS). It is proven that the scalar curvature r of an (L P K) m admitting an RYS satisfies the Poisson equation Δ r = 4 (m − 1) δ { β (m − 1) + ρ } + 2 (m − 3) r − 4 m (m − 1) (m − 2) , where ρ , δ (≠ 0) ∈ R . In this sequel, the condition for which the scalar curvature of an (L P K) m admitting an RYS holds the Laplace equation is established. We also give an affirmative answer for the existence of a GRYS on an (L P K) m . Finally, a non-trivial example of an L P -Kenmotsu manifold (L P K) of dimension four is constructed to verify some of our results. [ABSTRACT FROM AUTHOR]

In the era of globalization, information and communication technology (ICT) plays a crucial role in economic development and environmental sustainability. ICT enables economies to interact with each other around the globe, and the current fast ICT mode makes globalization a reality in today's technological world. However, its abrupt rise in installation and operation may increase energy demand and environmental degradation. Thus, this study embarks upon the role of ICT and financial development in shaping a low-carbon environment for sixty Belt and Road Initiative (BRI) economies using balanced panel data spanning 1990–2018. This study adopts the Driscoll–Kraay standard error long-run estimation technique and the Dumitrescu–Hurlin panel causality approach. The results reveal that ICT, financial development, and globalization are negatively related to CO2 emissions; however, economic growth and electricity consumption stimulate CO2 emissions, threatening environmental sustainability. Interestingly, a U-shaped relationship is observed between economic growth and CO2 emissions for BRI economies. Moreover, the causality results reveal bidirectional causal relationships between ICT, financial development and globalization with CO2 emissions. The findings urge the adoption of advanced ICT in the industrial sector for efficient energy use and socioeconomic development. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has significantly influenced antimicrobial use in hospitals, raising concerns regarding increased antimicrobial resistance (AMR) through their overuse. The objective of this study was to assess patterns of antimicrobial prescribing during the current COVID-19 pandemic among hospitals in Pakistan, including the prevalence of COVID-19. A point prevalence survey (PPS) was performed among 11 different hospitals from November 2020 to January 2021. The study included all hospitalized patients receiving an antibiotic on the day of the PPS. The Global-PPS web-based application was used for data entry and analysis. Out of 1024 hospitalized patients, 662 (64.64%) received antimicrobials. The top three most common indications for antimicrobial use were pneumonia (13.3%), central nervous system infections (10.4%) and gastrointestinal indications (10.4%). Ceftriaxone (26.6%), metronidazole (9.7%) and vancomycin (7.9%) were the top three most commonly prescribed antimicrobials among surveyed patients, with the majority of antibiotics administered empirically (97.9%). Most antimicrobials for surgical prophylaxis were given for more than one day, which is a concern. Overall, a high percentage of antimicrobial use, including broad-spectrums, was seen among the different hospitals in Pakistan during the current COVID-19 pandemic. Multifaceted interventions are needed to enhance rational antimicrobial prescribing including limiting their prescribing post-operatively for surgical prophylaxis. [ABSTRACT FROM AUTHOR]

Data centers (DC) play a very important role in higher educational institutions (HEIs) all over the world, particularly in Pakistan for the provision of expedited and reliable services, especially during the Covid-19 pandemic. Due to that educational and financial businesses have been shifted online, which increasing the mandate of virtual data center framework with the support of Learning Management Systems (LMS), and Enterprise Resource Planning (ERP) for HEIs. The main reasons preventing this adoption are the cost, complexity, and security. This paper proposed a cost-effective approach for traditional DC. This method-imposed VMware ESXI Hypervisor, which utilizes a single server machine to host multiple servers, vSwitches for network isolation and two DMZs (De-Militarized Zones) are set up along with Mikrotik router firewall policies implemented for the security of DC. The outcome of this study indicates that all the servers worked in the production environment, and the firewall coupled with DMZ implemented in the network prevented DDOS attacks, resulting in the continuity of DC services and security. [ABSTRACT FROM AUTHOR]

Level of toxic heavy metal concentration like lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), copper (Cu), zinc (Zn), and nickel (Ni) in thirty-six soft and hard organs and their impact on lipid profile of Hypophthalmichthys molitrix and Catla catla fish species inhibiting in Tanda Dam reservoir were investigated. The heavy metal concentrations in water, sediment, and fish of the different regions in the reservoir were determined with atomic absorption spectrophotometer. Lipid profile was carried out by AOAC official methods. The results showed that Pb was dominant among all the heavy metals in six organs, and its maximum concentration of Pb (22.5 mg kg-1 and 32.9 mg kg-1) was observed in scales in Hypophthalmichthys molitrix and tail of Catla catla, respectively. The maximum concentrations of Cd were observed in the head, scales, fins, and gills of Catla catla. The bioaccumulation of heavy metals was significantly different at (p ≤ 0.01) within the organs and between the fish species. The lipid concentration was minimum in those organs where the concentrations of heavy metals were maximum. It is clear from the findings that heavy metal accumulation reduces the lipid content of fish. It is inevitable to monitor the Tanda Dam reservoir to safeguard human health. [ABSTRACT FROM AUTHOR]

The paper deals with the study of Z-symmetric manifolds (Z S) n admitting certain cases of Schouten tensor (specifically: Ricci-recurrent, cyclic parallel, Codazzi type and covariantly constant), and investigate some geometric and physical properties of the manifold. Moreover, we also study (Z S) 4 spacetimes admitting Codazzi type Schouten tensor. Finally, we construct an example of (Z S) 4 to verify our result. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is of paramount concern globally. Community pharmacists (CPs) play a vital role in supporting judicious antimicrobial use in the community as they are the key healthcare providers at a public level. This study aimed to assess the knowledge, attitude, and perception of CPs towards antimicrobial stewardship at the community level in Saudi Arabia. A self-administered questionnaire was distributed to all community pharmacies in four major cities of Saudi Arabia. A simple random sampling approach was used to select pharmacies in each chain. A total of 520 CPs responded to the survey with a response rate of 98.6 %. Most of the pharmacists (n = 479, 92.1 %) accepted that antimicrobial stewardship programs are essential tools to limit injudicious usage of antimicrobials at the community level. Interestingly, very few (n = 105, 21 %) agreed to recommend antibiotics for common illnesses, including upper respiratory tract infections, cold, and flu without a valid prescription. Further, we found a significant role of Saudi health authorities, e.g., Saudi food & drug authorities and the Ministry of Health, in restricting antimicrobials sale in community pharmacies without a valid prescription. Our study findings revealed that CPs had good knowledge about antimicrobial stewardship in Saudi Arabia. The CPs play an active role in the optimization of antimicrobial therapy and infections caused by different microbes. Strict policies by the Saudi health care authority regarding the restricted dispensing of antimicrobials are welcomed by the CPs and thus may contribute toward lowering of antimicrobial resistance burden on the patients and Saudi health care authorities. [ABSTRACT FROM AUTHOR]

Dengue fever is a common viral disease presenting with a flu-like illness and bleeding manifestations. Although abdominal pain is a common presenting symptom of Dengue fever, gastrointestinal perforations are extremely rare. To date, only ten cases of gastrointestinal perforation have been reported in association with Dengue fever. We report a case of ileal perforation in a young patient who was diagnosed with Dengue fever. The disease was diagnosed with an x-ray abdomen and was treated with surgical exploration. The perforation was brought out as an ileostomy. Although rare, perforation peritonitis is highly fatal if left untreated. This must be considered early in the differentials of a Dengueinfected patient with signs of peritonitis. More studies are required to see into the patho-physiology of this association. [ABSTRACT FROM AUTHOR]

• Development of electrostatic retention model in mixed-mode liquid chromatography. • The model accurately predicted the retention of charged solutes at different pH. • Characterizing the phase system by acquiring single component adsorption isotherm. • Development of implicit electrostatic competitive adsorption isotherm model. • The model accurately predicted the competitive elution profiles for two components. This study investigated the influence of p H on the retention of solutes using a mixed-mode column with carboxyl (-COOH) groups acting as weak cation exchanger bonded to the terminal of C18 ligands (C18-WCX column) and a traditional reversed-phase C18 column. First, a model based on electrostatic theory was derived and successfully used to predict the retention of charged solutes (charged, and ionizable) as a function of mobile phase p H on a C18-WCX column. While the Horváth model predicts the p H-dependent retention of ionizable solutes in reversed-phase liquid chromatography (RPLC) solely based on solute ionization, the developed model incorporates the concept of surface potential generated on the surface of the stationary phase and its variation with p H. To comprehensively understand the adsorption process, adsorption isotherms for these solutes were individually acquired on the C18-WCX and reversed-phase C18 columns. The adsorption isotherms followed the Langmuir model for the uncharged solute and the electrostatically modified Langmuir model for charged solutes. The elution profiles for the single components were calculated from these isotherms using the equilibrium dispersion column model and were found to be in close agreement with the experimental elution profiles. To enable modelling of two-component cases involving charged solute(s), a competitive adsorption isotherm model based on electrostatic theory was derived. This model was later successfully used to calculate the elution profiles of two components for scenarios involving (a) a C18 Column: two charged solutes, (b) a C18 Column: one charged and one uncharged solute, and (c) a C18-WCX Column: two charged solutes. The strong alignment between the experimental and calculated elution profiles in all three scenarios validated the developed competitive adsorption model. [ABSTRACT FROM AUTHOR]