Central Face Research Articles

Green synthesis of silver nanoparticles using mature-pseudostem extracts of Alpinia nigra and their bioactivities

Abstract Green synthesis of silver nanoparticles (AgNPs) employing agricultural wastes as plant extracts to improve environmental benignity and also economic value added is the highlight of this research. The mature pseudostem of Alpinia nigra is an unbeneficial raw material discarded from several food ingredients and medicinal formulas. Therefore, this research focused on condition optimization for AgNP synthesis with ecofriendly techniques using A. nigra mature-pseudostem extracts and evaluation of their antioxidant, antibacterial activities, and toxicity with brine shrimp lethality assay (BSLA). The optimal reaction conditions were achieved by using 5 mM silver nitrate (AgNO3) solution with a volume ratio of 2:8 for the extract to AgNO3 at pH 12 under room temperature. The morphology and crystalline phase of the generated AgNPs were characterized using UV–visible spectrophotometry, field emission-scanning electron microscope (FE-SEM), energy dispersive X-ray, X-ray diffraction, and Fourier transform-infrared (FTIR) techniques. The FE-SEM analysis exposed spherical shapes with an average diameter of approximately 49 nm. The XRD analysis indicated their face center cubic structure, and the FTIR spectra confirmed that phytochemicals from A. nigra extract promoted the synthesis of AgNPs. In particular, the biosynthesized AgNPs presented potential antibacterial activity against both Staphylococcus aureus and Escherichia coli and effective antioxidant capacity using the DPPH radical scavenging assay. Additionally, non-toxic desired AgNPs were confirmed with BSLA.

Reinforcement concrete beams with external steel elements

The reinforcement of structural elements is widely practiced worldwide. It can be applied due to deterioration of the concrete, either due to age, change of use, extensions, or updating of the design code. However, it is sometimes used with inappropriate materials or without technical supervision or structural design. The main purpose of this paper is to investigate the method of strengthening based on the external addition of steel elements and to determine its influence on the flexural load-carrying capacity of reinforced concrete (RC) beams. For the same area of external steel, two types of beams are defined: the first one with cold-formed angle sections at the bottom corners, and the second one with a steel plate in the center of the tension face of the beam. The behavior of a total of 12 beams under monotonic and cyclic loading is experimentally studied. The connection was made with post-installed expanding bolts, without adhesives. The configuration that presents adequate results in terms of strength, flexibility, and energy, this obtained with the addition of a steel elements. On the other hand, the use of angled sections, contrary to expectations, reduces the load-carrying capacity and ductility of the section.

Corrosion behavior and mechanism of FeCoNi high-entropy alloy compared with X100 pipeline steel in a simulated alkaline soil environment

In this work, the corrosion behavior of FeCoNi HEA and X100 pipeline steel in a simulated Golmud soil environment was systematically studied utilizing electrochemical tests, surface analysis techniques and immersion measurement. The results indicate that FeCoNi HEA possesses superior anti-corrosion property than X100 steel by comparing the charge transfer resistance (Rct), passive current density (ip) and corrosion morphology. The microstructure and surface film are the principal factors causing the difference in corrosion resistance of the two alloys. More intact, uniform and dense passive film enhances the anti-corrosion performance of the HEA, while the nonprotective, loose and defective corrosion product film covering the surface of X100 steel is not conducive to inhibiting the corrosion of the steel substrate. The appearance of inclusions within the HEA can generate the micro-galvanic corrosion effect with the matrix, which promotes the substrate as an anode to induce pitting. Furthermore, multiple phases of X100 steel exhibits higher electrochemical activity compared to the HEA with a single Face Center Cubic (FCC) phase, which accelerates the corrosion of the steel. Moreover, the matrix of the HEA primarily experiences selected dissolution of Ni element.

Experimental study on the immersion liquid cooling performance of high-power data center servers

Highly dense and integrated data centers face key challenges of realizing efficient cooling and improved energy efficiency. To overcome these challenges, this study experimentally investigated the flow and heat transfer characteristics of single-phase immersion liquid cooling (SPILC) systems. The influence of two opposite coolant flow directions on the SPILC performance was examined. Furthermore, a correlation mechanism between coolant thermal properties and SPILC performance was established, along with a control chart for regulating the working conditions of SPILC systems. The results indicate that compared to a pro-gravity flow, an anti-gravity flow scheme reduces the chip case temperature and thermal resistance by 33.8% and 55.6%, respectively, while decreasing the power usage effectiveness (PUE) by 1.4%. Using coolant with the lowest viscosity reduces the chip case temperature and thermal resistance by 9.3% and 10.5%, respectively, while decreasing the PUE by 0.4%. Moreover, the cooling water temperature has a greater impact on the performance of SPILC systems than the volume flow rate of coolants. Additionally, this paper provides control charts for the cooling water temperature and coolant flow rate to improve the PUE while ensuring the safe operation of SPILC systems, with the highest chip temperature and total electricity consumption as indicators.

Rock fracturing mechanism and arrangement of fracturing holes using hydro-mechanical splitters

For more-efficient tunneling in hard rock, reported here are simulations and experiments to analyze the rock fracturing mechanism and determine the optimal arrangement of fracturing holes when using hydro-mechanical splitters in tunnel excavation. First, a numerical model of rock fracturing is established using the cohesive-zone model, enabling analysis of the relationship between fracturing force and crack surface development during rock fracturing; this analysis involves examining the mechanisms for crack propagation and stress evolution, thereby comprehensively assessing the mechanism for rock fracturing using a hydro-mechanical splitter. Next, the stress evolution and crack propagation with multiple fracturing holes arranged in either a line or a circle are analyzed; how the fracturing force varies with different numbers of fracturing holes is obtained, and a method of using free-face unloading for circular expansion with a central free face is proposed. Finally, the tunnel contour control of rock fracturing using hydro-mechanical splitters is studied experimentally and ideal peripheral and bottom contours are obtained, thereby providing a way to use rock fracturing technology based on hydro-mechanical splitters for tunneling in hard rock.

Effect of Minimum Quantity of Lubricant on Carbide Tools and Surface Integrity in the Machining of Titanium Aluminides

Titanium aluminides are being explored as potential materials for the aeronautical sector. However, their application is limited by the high costs of processing and their difficulties in machining. This research evaluates the effectiveness of the minimum quantity lubrication technique (MQL) on the turning process of Ti48Al2Cr2Nb aluminide in terms of tool wear, tool life, cutting forces, surface integrity, and temperature. It was found that MQL conditions can improve the process efficiency, reducing the thermally induced wear mechanisms and enlarging the tool life compared to dry machining. Furthermore, it allows the cutting speed to be incremented, leading to lower processing times. However, MQL seems to not be effective in the reduction of the strain-hardening effect near the machined surface and, although the number of microcracks is reduced, defect-free surfaces cannot be obtained. Moreover, similar microstructural alterations as for dry cutting were detected. The best cutting conditions in terms of surface quality were assessed using the central composite face (CCF) design and surface response methodology. Optimization of the surface roughness under industrially viable cutting conditions was achieved with an average surface roughness value, Ra, of 0.29 µm (feed rate of 0.05 mm/rev, a cutting speed of 54.6 m/min and a depth of cut of 0.125 mm).

Utilization of herbivore defensive latex from the weed Calotropis procera L in the green synthesis of silver nanoparticles and its potential application in the control of dengue vector Aedes aegypti

Milky latex produced by few and not all the plants are the treasure chest of various bioactive compounds with defensive potential against herbivores, insects and pathogens. Mankind have utilized latices in the preparation of novel plant-based therapies for centuries. Therefore, an attempt has been made to synthesis silver nanoparticles (AgNPs) using AgNO3 as a precursor and latex from C. procera as a reducing agent. The surface plasmon absorption peak at 430 nm confirmed AgNPs formation. The sharp peak with narrow width illustrated the homogenous nature. The face centre cubic structure of AgNPs was confirmed by the XRD pattern. FT-IR analysis deduced that the bio-molecules in the latex of C. procera are responsible for the reduction of AgNO3 to AgNPs. Biosynthesised L-AgNPs possessed well pronounced antibacterial activity against P. aeruginosa and K. pneumoniae. Anti-inflammatory activity of the nanoparticle determined by membrane stabilization and proteinase inhibitory assay was found to be in dose-dependent. LC50 value of L-AgNPs was found to be 63.09 µg/mL against IV instar larvae of A. aegypti. Distinct morphological changes were observed in the mosquito larva on exposure to various concentrations of L-AgNPs.

Investigation of structural, electrical and thermoelectric properties of cobalt-zinc ferrites/graphene nanocomposite

The present work was related to synthesis of graphene (0, 1.25 and 2.5 %) incorporation in cobalt-zinc ferrites by using sol–gel auto combustions method. The face center cubic (FCC) crystal structure and crystallite size varies from 16 to 18 nm was examined by XRD analysis. While as the irregular, non-uniform and flake like surface morphology of cobalt zinc/graphene nanocomposite (Co-Zn-G NCs) were observed via SEM images. In addition, the phase identification and presence of different functional groups such as M−O (metal oxide), OH, C-C, C = O and C = C were investigated by Raman spectroscopy and FTIR analyses. Further, I-V two probe method was used to observed the resistivity decrease (7.5x 108 to 2.5x 106 ohm-cm) and conductivity increased (1.2x10-9 to 3.8x10-7S/cm) of Co-Zn-G NCs. After that the thermoelectric behavior of Co-Zn-G NCs indicated that due to increase the temperature then seebeck coefficient decrease as vice versa. The overall result shows that the 2.5 % graphene incorporation in Co-Zn ferrites expressed the excellent electrical and thermoelectric properties. In future the Co-Zn-G nanocomposite used for the development of temperature sensor, reduce eddy current loss and spintronic devices.

Disambiguating vision with sound

An important task for the visual system is to identify and segregate objects from background. Figure-ground illusions, such as Edgar Rubin's bistable 'vase-faces illusion'1, make the point clearly: we see either a central vase or lateral faces, alternating spontaneously, but never both images simultaneously. The border is perceptually assigned to either faces or vase, which become figure, the other shapeless background2. The stochastic alternation between figure and ground probably reflects mutual inhibitory processes that ensure a single perceptual outcome3. Which shape dominates perception depends on many factors, such as size, symmetry, convexity, enclosure, and so on, as well as attention and intention4. Here we show that the assignment of the visual border can be strongly influenced by auditory input, far more than is possible by voluntary intention. VIDEO ABSTRACT.

Competition between emotional faces in visuospatial working memory.

Visuospatial working memory (VSWM) helps track the identity and location of people during social interactions. Previous work showed better VSWM when all faces at encoding displayed a happy compared to an angry expression, reflecting a prosocial preference for monitoring who was where. However, social environments are not typically uniform, and certain expressions may more strongly compete for and bias face monitoring according to valence and/or arousal properties. Here, we used heterogeneous encoding displays in which two faces shared one emotion and two shared another, and asked participants to relocate a central neutral probe face after a blank delay. When considering the emotion of the probed face independently of the co-occurring emotion at encoding, an overall happy benefit was replicated. However, accuracy was modulated by the nonprobed emotion, with a relocation benefit for angry over sad, happy over fearful, and sad over happy faces. These effects did not depend on encoding fixation time, stimulus arousal, perceptual similarity, or response bias. Thus, emotional competition for faces in VSWM is complex and appears to rely on more than simple arousal- or valence-biased mechanisms. We propose a "social value (SV)" account to better explain when and why certain emotions may be prioritized in VSWM. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Attentional processing of preserved face and scrambled face distractors in preschool children with autism spectrum condition

ABSTRACT The current study investigated attentional processing of preserved neutral face and scrambled neutral face distractors at both involuntary and voluntary orienting levels in children with and without autism spectrum condition (ASC). The findings suggest similar influences of face configuration on reflexive orienting in both groups but reveal group differences in voluntary disengagement from face-related distractors. The ASC group exhibited difficulties in disengaging from the central neutral faces, and the TD group showed longer latencies for scrambled faces. These group differences suggest inefficiency in adopting a global face processing strategy at the voluntary attentional level in ASC. We discuss how the observed effects might impact upon the development of social communication skills in ASC.

How to Quickly and Affordably Reduce Corneal Neovascularization

Abstract
 Introduction : Fine needle diathermy (FND) is one of the treatment modalities for corneal neovascularization (CoNV). Occlusion of the CoNV will reduce vascular leakage, thus preserving visual acuity. This case report presents FND as a treatment for CoNV due to ocular rosacea.
 Case Illustration : A 25-year-old volleyball athlete came to Cicendo Eye Hospital after experiencing blurry vision for a week, followed by flushing on the face. A general examination revealed telangiectasia and pustules on the central face (Figure 1). Visual acuity was 0.2 RE. A slit-lamp examination revealed hyperemiain the lid margins, oedema, and superficial-stromal neovascularization on the cornea (Figure 2). The patient was diagnosed with blepharo-kerato-conjunctivitis on RE due to ocular rosacea. The patient then underwent FND (Figure 3). The procedure was performed by using a 10.0-gauge needle inserted in the corneal stroma along the CoNV. The vessels were occluded by conducting monophasic diathermy at a power of 1 mA (Figure 4). On the 5th day, corneal oedema and neovascularization were reduced, and visual acuity improved to 0.4 ph 0.5 (Figure 5).
 Discussion : Corneal neovascularization may affect corneal transparency and thus reduce visual acuity. FND is relatively affordable and widely available. Compared to another modality, FND has not been widely performed to treat CoNV. A literature search using PubMed or Google Scholar found few case reports or reviews regarding successful cases of FND.
 Conclusion : Fine needle diathermy is a safe and effective treatment for CoNV due to ocular rosacea. Further studies should be conducted to evaluate the safety and long-term efficacy of FND.

Evaluation of Delayed Contact Hypersensitivity in Patients with Rosacea

Introduction: Rosacea is a common chronic inflammatory dermatosis characterized by erythema, telangiectasia, papules, and pustules on the central face. The frequency of contact sensitization complicating rosacea and its therapy is unknown, with only few studies published in the literature. In the present study, we aimed to evaluate contact sensitivity in patients with rosacea. Methods: A total of 50 rosacea patients and 50 age- and sex-matched healthy controls were enrolled. Both groups were patch tested with the European Baseline Series. Results: A positive reaction to at least one allergen of the European Baseline Series was observed in 15 (30%) of rosacea patients and 10 (20%) of the healthy controls. Although the rate of positive reaction in the rosacea group was higher than in the controls, no statistically significant difference was documented. In addition, the total number of positive reactions to allergens in the rosacea group was higher than the control group, namely, 26 versus 17. Conclusion: Contact hypersensitivity may coexist with rosacea. Its identification holds significant clinical relevance, influencing the long-term management and justifying the application of patch testing in rosacea patients.

Wave absorbing properties of Ni Nanoparticle/CNT composite film fabricated by AAO/CNTs electrode

An effective wave absorbing Nano-Ni/carbon nanotubes (CNTs) composite film was developed by electrodeposition using an anodic aluminum oxide (AAO)/CNTs electrode. Scanning electron microscopy images confirmed the uniform dispersion of Ni nano-particles within the CNTs, and the particle diameter increasing from 20 nm to 100 nm as the deposition time increased. XRD test results revealed that the crystal phase of the Ni nano-particles remained unchanged during different deposition time, exhibiting a Face Center Cubic (fcc) structure. The microwave electromagnetic properties of the film were evaluated using a vector network analyzer, and the return loss curve demonstrated that the Ni nano-particles/CNTs composite exhibited exceptional wave absorption capabilities. The composite film showed an effective absorption width of 13 GHz (4–17 GHz) and achieved a minimum reflection loss (RL) of −17 dB at 14 GHz.

Nonthermal Plasma Synthesis of Metallic Ti Nanocrystals

Nanoscale metallic titanium (Ti) offers unique energetic and biocompatible characteristics for the aerospace and biomedical industries. A rapid and sustainable method to form purified Ti nanocrystals is still in demand due to their high oxygen affinity. Herein, we report the production of highly purified Ti nanoparticles with a nonequilibrium face center cubic (FCC) structure from titanium tetrachloride (TiCl4) via a capacitively coupled plasma (CCP) route. Furthermore, we demonstrate a secondary H2 treatment plasma as an effective strategy to improve the air stability of a thin layer of nanoparticles by further removal of chlorine from the particle surface. Hexagonal and cubic-shaped Ti nanocrystals of high purity were maintained in the air after the secondary H2 plasma treatment. The FCC phase potentially originates from small-sized grains in the initial stage of nucleation inside the plasma environment, which is revealed by a size evolution study with variations of plasma power input.

The Heart of the World.

Cardiovascular diseases (CVDs) are the leading cause of mortality globally. Of the 20.5 million CVD-related deaths in 2021, approximately 80% occurred in low- and middle-income countries. Using data from the Global Burden of Disease Study, NCD Risk Factor Collaboration, NCD Countdown initiative, WHO Global Health Observatory, and WHO Global Health Expenditure database, we present the burden of CVDs, associated risk factors, their association with national health expenditures, and an index of critical policy implementation. The Central Europe, Eastern Europe, and Central Asia region face the highest levels of CVD mortality globally. Although CVD mortality levels are generally lower in women than men, this is not true in almost 30% of countries in the North Africa and Middle East and Sub-Saharan regions. Raised blood pressure remains the leading global CVD risk factor, contributing to 10.8 million deaths in 2019. The regions with the highest proportion of countries achieving the maximum score for the WHF Policy Index were South Asia, Central Europe, Eastern Europe, and Central Asia, and the High-Income regions. The Sub-Saharan Africa region had the highest proportion of countries scoring two or less. Policymakers must assess their country's risk factor profile to craft effective strategies for CVD prevention and management. Fundamental strategies such as the implementation of National Tobacco Control Programmes, ensuring the availability of CVD medications, and establishing specialised units within health ministries to tackle non-communicable diseases should be embraced in all countries. Adequate healthcare system funding is equally vital, ensuring reasonable access to care for all communities.

Two-year audit of compliance in the preparation and administration of medications by nursing staff in a mother-and-child university hospital center

ObjectiveAudits are essential for reviewing and improving the medication-use process. Identifying areas for improvement can limit the risk of errors when preparing and administering drugs. Pediatric centers face specific challenges in ensuring the safety of the medication-use process. The objective of this study was to observe and compare compliance with criteria for the preparation and administration of medications by nurses in a mother-and-child university hospital center over two consecutive years. MethodsThis observational cross-sectional study was conducted in a Canadian mother-and-child university hospital center. Audits were conducted over a 1-month period in 16 and 18 nursing care sectors in 2021 and 2022, respectively. The standardized audit evaluated compliance with prespecified criteria related to the preparation and administration of medication by nursing staff (77 criteria for 2021 and 82 criteria for 2022). The auditors comprised nurses and a pharmacist trained by the research team. Compliance was compared between years and assessed through a chi-square test. ResultsThe audit consisted of 522 observations in 2021 and 448 observations in 2022. Overall compliance was 76% in 2021 and 66% in 2022. The compliance rate by criterion ranged from 16% to 100%. In 2021 and 2022, 51 (84%) and 52 (87%) of the criteria, respectively, had compliance rates of more than 75%, and 12 (20%) and eight (13%), respectively, had 100% compliance. There were statistically significant decreases in compliance for nine of the 39 criteria for preparation of medications, notably prior hand hygiene (91%% vs. 84%, p = 0.002), and for six of the 17 criteria for administration of medications, including mentioning possible adverse effects to the patient (41% vs- 30%, p = 0.008). ConclusionIn this study, compliance was over 75% for most of the criteria. However, for a few criteria, we observed a decrease in compliance from 2021 to 2022. Various hypotheses are proposed to explain these decreases, such as the COVID-19 pandemic.

Advances in the Pathogenesis and Treatment of Rosacea: A Phenotype-Based Therapeutic Approach

Rosacea is a common chronic inflammatory skin disorder that mainly affects the central face. It is primarily characterized by recurrent episodes of flushing, persistent erythema, inflammatory papules, telangiectasias, phymatous changes, and ocular symptoms. Its pathogenesis is complex and still not completely understood. It encompasses innate and adaptive immune system dysregulation, neurovascular dysfunction, and genetic and environmental factors. To date, four subtypes of rosacea have been identified, based on the predominant clinical features: erythemato-teleangiectatic, papulopustular, pyhomatous, and ocular rosacea. New insights into this condition have led to several pharmacological treatments, including topical medications, spanning from the conventional azelaic acid, metronidazole, benzoyl peroxide, clindamycin, and erythromycin to new ones including not only brimonidine, oxymetazoline, ivermectine, and minocycline but also systemic drugs such as oral antibiotics, isotretinoin, non-selective β-blockers or α2-adrenergic agonists, and laser- or light-based therapies, together with new therapeutic approaches. The aim of this study was to review the current literature on the pathophysiology of rosacea and to provide an overview of therapeutic approaches that specifically address each clinical subtype.

Full-variable Cartesian grid method for incompressible and multiphase flows

We propose an efficient incompressible fluid solver based on a Cartesian grid and multi-moment concept. In the proposed method, velocity variables are located at cell centers, face centers and nodes in 2D, and cell centers, face centers, edge centers and nodes in 3D but the pressure variables are located only at the cell centers. The Cartesian grid is called full-variable Cartesian grid (FVCG) and the proposed method is called FVCG method. By using the FVCG method, we could improve velocity calculations (error reduction and numerical oscillation suppression) without significant increase in computational time. For instance, in a 3D multiphase flow simulation, although the FVCG method uses twice velocity resolution compared to existing methods, the increase in computational time was only 2%-9%. The FVCG method was validated through various benchmark problems, and comparisons with experiments of coalescence and separations of two liquid droplets (three different cases) and droplet splashing on a superhydrophobic substrate. These numerical results have shown that the FVCG method can efficiently simulate incompressible flows and free surface flows which involve highly complex surface topology changes with coarse grids. These numerical results have also shown that the FVCG method is robust.

The role of the Kepong Guidance Center in shaping the character of students and fostering a noble Islamic generation

Noble character is very important for students, and this research will see how each student's character develops. Kepong Guidance Center is a place of study for undocumented Indonesian students living in Malaysia. This consultancy studio supports the teaching of Indonesian students in Malaysia. This article is structured as follows: 1) Religious education is very important to develop students' morally upright character. However, because everyone's temperament varied greatly, it was common for students to get along badly, 2) The aim of this study is to investigate the role of the Kepong Guidance Center in shaping the character of students. 3) This study used qualitative approach and the method of the data collection was using observations and interviews. 4) engage in activities that help children develop their character and adopt noble attitudes, such as placing them in groups to plan lessons and encourage sharing. 5) Based on the findings above, it can be concluded that the teachers at Kepong Guidance Center play a crucial role in shaping the character of students and fostering a noble Islamic generation. The study showed that the students' character improved swiftly and that they found it easy to understand and practice what had been taught and guided. However, many students still require additional instruction to further develop their admirable character traits, and many pupils at the Kepong Guidance Center face challenges in their homes.