Muhammad Asad

Caffeic Acid Phenethyl Ester and Therapeutic Potentials

Caffeic acid phenethyl ester (CAPE) is a bioactive compound of propolis extract. The literature search elaborates that CAPE possesses antimicrobial, antioxidant, anti-inflammatory, and cytotoxic properties. The principal objective of this review article is to sum up and critically assess the existing data about therapeutic effects of CAPE in different disorders. The findings elaborate that CAPE is a versatile therapeutically active polyphenol and an effective adjuvant of chemotherapy for enhancing therapeutic efficacy and diminishing chemotherapy-induced toxicities.

Anti-Aging Potential of Phytoextract Loaded-Pharmaceutical Creams for Human Skin Cell Longetivity.

The exposure to ultraviolet radiations (UVR) is the key source of skin sunburn; it may produce harmful entities, reactive oxygen species (ROS), leading to aging. The skin can be treated and protected from the injurious effects of ROS by using various pharmaceutical formulations, such as cream. Cream can be loaded with antioxidants to quench ROS leading to photo-protective effects. Moreover, modern medicines depend on ethnobotanicals for protection or treatment of human diseases. This review article summarizes various in vivo antioxidant studies on herbal creams loaded with phyto-extracts. These formulations may serve as cosmeceuticals to protect skin against injurious effects of UVR. The botanicals studied for dermatologic use in cream form include Acacia nilotica, Benincasa hispida, Calendula officinalis, Camellia sinensis, Camellia sinensis, Nelumbo nucifera, Capparis decidua, Castanea sativa, Coffea arabica, Crocus sativus, Emblica officinalis Gaertn, Foeniculum vulgare, Hippophae rhamnoides, Lithospermum erythrorhizon, Malus domestica, Matricaria chamomilla L., Moringa oleifera, Morus alba, Ocimum basilicum, Oryza sativa, Polygonum minus, Punica granatum, Silybum marianum, Tagetes erecta Linn., Terminalia chebula, Trigonella foenum-graecum, and Vitis vinifera. The observed anti-aging effects of cream formulations could be an outcome of a coordinating action of multiple constituents. Of numerous botanicals, the phenolic acids and flavonoids appear effective against UVR-induced damage; however the evidence-based studies for their anti-aging effects are still needed.

Finite-element-based hybrid dynamic cutting model for aluminium alloy milling

Abstract The present contribution deals with milling tool vibration effects on chip morphology, cutting force, and cut surface topology. The study concerns an orthogonal down-cut peripheral milling case for aeronautic aluminium alloy A2024-T351. A finite-element-based hybrid dynamic cutting model (HDC model) is proposed to predict the chip morphology under dynamic cutting conditions. The latter is conceived with commercial software ABAQUS®/EXPLICIT and combines the stiffness of a high-speed milling spindle system (tool, toolholder, and rotor) with the chip formation process. A qualitative parametric study with various stiffness and damping coefficient values for a high-speed milling spindle system has been performed. The results concerning chip morphology and cutting force are compared with experimental data, while the surface profiles are compared with those obtained by considering a perfectly rigid spindle system. As expected, a less rigid undamped milling system generates higher-amplitude tool vibrations during milling. In this situation, the temperature rises at the tool—workpiece interface, enhancing material softening. This softening promotes chip segmentation and increases waviness of the machined surface profile. The numerical results show that higher values of cutting speed and uncut chip thickness are associated with higher vibration amplitudes.

Three-dimensional finite element modeling of rough to finish down-cut milling of an aluminum alloy

This contribution deals with a computational investigation highlighting the effects of cutting speed and depth of cut on chip morphology and surface finish for down-cut milling case. The global aim concerns the comprehension of multiphysical phenomena accompanying chip formation in rough, semifinish, and finish cutting operations, exploiting a three-dimensional finite element model. Numerical work has been performed in two phases. In the first phase, a three-dimensional model for rough cut operation has been validated with the experimental results, including chip morphology and cutting force evolution for an aerospace grade aluminum alloy A2024-T351. In the second phase, the model has been extended to semifinish and finish three-dimensional cutting operations. The numerical findings show that as depth of cut decreases (toward finish cutting), spatial displacement of workpiece nodes along the depth of cut increases. This represents an increase/extension in the percentage of volume undergoing shear deformation, resulting in higher dissipation of inelastic energy, hence contributing to size effect in finish cutting operation. The results also depict that material strain rate hardening enhances the material strength at higher cutting speeds. These material strengthening phenomena help to generate a smooth continuous chip morphology and better surface texture in high-speed finishing operations. The study highlights the significance of three-dimensional numerical modeling to better understand the chip formation process in semifinish and finish machining operations, regardless of the immense effort in computational time.

A parametric sensitivity study on preforming simulations of woven composites using a hypoelastic computational model

Preforming simulation for structural composite processing can significantly assist in the development of forming tools, prediction of manufacturing issues, optimization of process parameters and structural design analysis. The present study is aimed at investigating the influence of some important parameters in composite forming using a hypoelastic computational model developed for simulating the deformation behaviour of fibrous materials. The process parameters considered within this numerical work investigate the effects of binder force, coefficient of friction and forming speed. The study is conducted using two most commonly used double-curvature geometries for analysis of woven composites: double dome and hemisphere. It has been shown with this comprehensive study that the forming simulations are greatly affected by the choice of process parameters, and models based on finite element approach, such as the proposed hypoelastic model, can only predict its effects.

Turning modeling and simulation of an aerospace grade aluminum alloy using two-dimensional and three-dimensional finite element method

This article presents the development of two-dimensional and three-dimensional finite element–based turning models, for better prediction of chip morphology and machined surface topology. Capabilities of a commercial finite element code Abaqus®/Explicit have been exploited to perform coupled temperature–displacement simulations of an aerospace grade aluminum alloy A2024-T351 machining. The findings show that two-dimensional cutting models predict chip morphologies and machined surface textures on a plane section (with unit thickness) passing through the center of workpiece width, and not at the edges. The contribution highlights the importance of three-dimensional machining models for a close corroboration of experimental and numerical results. Three-dimensional cutting simulations show that a small percentage of material volume flows toward workpiece edges (out of plane deformation), augmenting the contact pressures at the edges of tool rake face–workpiece interface. This enhances the burr formation process. Computational results concerning chip morphologies and cutting forces were found in good correlation with experimental ones. In the final part of the article, numerical simulation results with a modified version of a particular turning tool have been discussed. It has been found that the proposed geometry of the tool is helpful in reducing burr formation as well as cutting force amplitude during initial contact of cutting tool with the workpiece material.

Prevalence of Extended Spectrum β-Lactamase and Antimicrobial Susceptibility Pattern of Clinical Isolates of Pseudomonas from Patients of Khyber Pakhtunkhwa, Pakistan.

Majority of gram negative pathogenic bacteria are responsible for extended spectrum β-lactamases (ESBLs) production, which show resistance to some newer generation of antibiotics. The study was aimed at evaluating the prevalence of ESBL and antibiotic susceptibility pattern of Pseudomonas isolates collected during 2010 to 2014 from tertiary care hospitals of Peshawar, Pakistan. Out of 3450 samples, 334 Pseudomonas spp. isolates comprised of 232 indoor and 102 outdoor patients were obtained from different specimens and their susceptibility pattern was determined against 20 antibiotics. Antimicrobial susceptibility testing was carried out using the Kirby-Bauer agar diffusion method and ESBL production was detected by Synergy Disc Diffusion technique. The mean age group of the patients was 29.9 + 9.15 years. Meronem showed best activity (91.02%) from class carbapenem, β-lactam and β-lactamase inhibitors exhibited 69.16% activity, and doxycycline had a diminished activity (10.18%) to Pseudomonas spp. Outdoor isolates were more resistant than the indoor and during the course of the study the sensitivity rate of antibiotics was gradually reducing. ESBL production was observed in 44.32% while the remaining was non-ESBL. The moderate active antibiotics were amikacin (50.7%), SCF (51.4%), TZP (52.7%), and MXF (54.1%) among ESBL producing isolates. Lack of antibiotic policy, irrational uses (3GCs particularly), and the emergence of antibiotic resistant organisms in hospitals may be causes of high antibiotic resistance.

Naja naja karachiensis Envenomation: Biochemical Parameters for Cardiac, Liver, and Renal Damage along with Their Neutralization by Medicinal Plants

Naja naja karachiensis envenomation was found to hit more drastically heart, liver, and kidneys. 400 μg/kg of venom-raised moderate serum levels of ALT (72 ± 4.70 U/L, 0.1 > P > 0.05), AST (157 ± 24.24 U/L, 0.1 > P > 0.05), urea (42 ± 3.08 mg/dL, 0.05 > P > 0.02), creatinine (1.74 ± 0.03 mg/dL, 0.01 > P > 0.001), CK-MB (21 ± 1.5 U/L, 0.05 > P > 0.02), and LDH (2064 ± 15.98 U/L, P < 0.001) were injected in experimental rabbits. However, lethality was enhanced with 800 μg/kg of venom in terms of significant release of ALT (86 ± 5.0 U/L, 0.05 > P > 0.02), AST (251 ± 18.2 U/L, 0.01 > P > 0.001), urea (57.6 ± 3.84 mg/dL, 0.02 > P > 0.01), creatinine (2.1 ± 0.10 mg/dL, 0.02 > P > 0.01), CK-MB (77 ± 11.22 U/L, 0.05 > P > 0.02), and LDH (2562 ± 25.14 U/L, P ≪ 0.001). Among twenty-eight tested medicinal plant extracts, only Stenolobium stans (L.) Seem was found the best antivenom (P > 0.5) compared to the efficacy of standard antidote (ALT = 52.5 ± 3.51 U/L, AST = 69.5 ± 18.55 U/L, urea = 31.5 ± 0.50 mg/dL, creatinine = 1.08 ± 0.02 mg/dL, CK-MB = 09 ± 0.85 U/L, and LDH = 763 ± 6.01 U/L). Other plant extracts were proved less beneficial and partly neutralized the toxicities posed by cobra venom. However, it is essential in future to isolate and characterize bioactive compound(s) from Stenolobium stans (L.) Seem extract to overcome the complications of snake bite.

Anti-Cancerous Potential of Polyphenol-Loaded Polymeric Nanotherapeutics

Recent evidence has extensively demonstrated the anticancer potential of nutraceuticals, including plant polyphenols. Polymeric nanocarrier systems have played an important role in improving the physicochemical and pharmacological properties of polyphenols, thus ameliorating their therapeutic effectiveness. This article summarizes the benefits and shortcomings of various polymeric systems developed for the delivery of polyphenols in cancer therapy and reveals some ideas for future work.

A Multiscale Cutting Model Based on the Theory of Gradient Plasticity

The present paper highlights the importance of size effect consideration during the modelling of material removal by cutting tool, especially when passing from maco-to-micro scales. For that, the presented study concerns an orthogonal case of down-cut milling where the chip thickness is evolving. Consequently, to capture the scale effect when passing from macro to micro dimensions, the theory of gradient plasticity were adopted.