Pakistan Institute of Engineering and Applied Sciences

Zerovalent copper nanoparticles (Cu0) of 12 nm size were synthesized using an inert gas condensation method in which bulk copper metal was evaporated into an inert environment of argon with subsequent cooling for nucleation and growth of nanoparticles. Crystalline structure, morphology and estimation of size of nanoparticles were carried out by X-ray diffraction and transmission electron microscopy. The antibacterial activity of these nanoparticles against the Gram-negative bacterium Escherichia coli was assessed in liquid as well as solid growth media. It was observed from scanning electron microscopic analysis that the interaction of copper nanoparticles with E. coli resulted in the formation of cavities/pits in the bacterial cell wall. The antibacterial property of copper nanoparticles was attributed mainly to adhesion with bacteria because of their opposite electrical charges, resulting in a reduction reaction at the bacterial cell wall. Nanoparticles with a larger surface-to-volume ratio provide more efficient means for antibacterial activity.

Generative adversarial network (GANs) is one of the most important research avenues in the field of artificial intelligence, and its outstanding data generation capacity has received wide attention. In this paper, we present the recent progress on GANs. First, the basic theory of GANs and the differences among different generative models in recent years were analyzed and summarized. Then, the derived models of GANs are classified and introduced one by one. Third, the training tricks and evaluation metrics were given. Fourth, the applications of GANs were introduced. Finally, the problem, we need to address, and future directions were discussed.

The rhizosphere is undoubtedly the most complex microhabitat, comprised of an integrated network of plant roots, soil, and a diverse consortium of bacteria, fungi, eukaryotes, and archaea. The rhizosphere conditions have a direct impact on crop growth and yield. Nutrient-rich rhizosphere environments stimulate plant growth and yield and vice versa. Extensive cultivation exhaust most of the soils which need to be nurtured before or during the next crop. Chemical fertilizers are the major source of crop nutrients but their uncontrolled and widespread usage has posed a serious threat to the sustainability of agriculture and stability of an ecosystem. These chemicals are accumulated in the soil, drained in water, and emitted to the air where they persist for decades causing a serious threat to the overall ecosystem. Plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere convert many plant-unavailable essential nutrients e.g., nitrogen, phosphorous, zinc, etc. into available forms. PGPR produces certain plant growth hormones (such as auxin, cytokinin, and gibberellin), cell lytic enzymes (chitinase, protease, hydrolases, etc.), secondary metabolites, and antibiotics, and stress alleviating compounds (e.g., 1-Aminocyclopropane-1- carboxylate deaminase), chelating agents (siderophores), and some signaling compounds (e.g., N-Acyl homoserine lactones) to interact with the beneficial or pathogenic counterparts in the rhizosphere. These multifarious activities of PGPR improve the soil structure, health, fertility, and functioning which directly or indirectly support plant growth under normal and stressed environments. Rhizosphere engineering with these PGPR has a wide-ranging application not only for crop fertilization but developing eco-friendly sustainable agriculture. Due to severe climate change effects on plants and rhizosphere biology, there is growing interest in stress-resilient PGPM and their subsequent application to induce stress (drought, salinity, and heat) tolerance mechanism in plants. This review describes the three components of rhizosphere engineering with an explicit focus on the broader perspective of PGPM that could facilitate rhizosphere engineering in selected hosts to serve as an efficient component for sustainable agriculture.

Since their discovery in 2011, 2D transition metal carbides, nitrides, and carbonitrides, known as MXenes, have attracted considerable global research interest owing to their outstanding electrical conductivity coupled with light weight, flexibility, transparency, surface chemistry tunability, and easy solution processability. Here, the promising abilities of 2D MXenes, from both experimental and theoretical perspectives, for designing conductive materials for a range of applications, including electromagnetic interference shielding, flexible optoelectronics, sensors, and thermal heaters, are presented.

Paper-based microfluidics is the branch of microfluidics involving devices made out of paper, or other porous membranes, that wick fluids by capillary action. Paper-based microfluidic devices have several advantages over conventional microfluidic devices including simpler fabrication, lower cost, easier disposal, and the ability to operate without pumps or other supporting equipment. The most common application of paper-based microfluidic devices is in the development of point-of-care (POC) diagnostic devices, which could eliminate the need for costly and time-consuming laboratory-based analytical procedures. This review provides an overview of current methods of fabricating paper-based microfluidic devices, examples of applications of these devices, a discussion of their current limitations, and an outlook on their future.

Salinity is a growing problem affecting soils and agriculture in many parts of the world. The presence of salt in plant cells disrupts many basic metabolic processes, contributing to severe negative effects on plant development and growth. This review focuses on the effects of salinity on chloroplasts, including the structures and function of these organelles. Chloroplasts house various important biochemical reactions, including photosynthesis, most of which are considered essential for plant survival. Salinity can affect these reactions in a number of ways, for example, by changing the chloroplast size, number, lamellar organization, lipid and starch accumulation, and interfering with cross-membrane transportation. Research has shown that maintenance of the normal chloroplast physiology is necessary for the survival of the entire plant. Many plant species have evolved different mechanisms to withstand the harmful effects of salt-induced toxicity on their chloroplasts and its machinery. The differences depend on the plant species and growth stage and can be quite different between salt-sensitive (glycophyte) and salt-tolerant (halophyte) plants. Salt stress tolerance is a complex trait, and many aspects of salt tolerance in plants are not entirely clear yet. In this review, we discuss the different mechanisms of salt stress tolerance in plants with a special focus on chloroplast structure and its functions, including the underlying differences between glycophytes and halophytes.

Metabolomic data are frequently acquired using chromatographically coupled mass spectrometry (MS) platforms. For such datasets, the first step in data analysis relies on feature detection, where a feature is defined by a mass and retention time. While a feature typically is derived from a single compound, a spectrum of mass signals is more a more-accurate representation of the mass spectrometric signal for a given metabolite. Here, we report a novel feature grouping method that operates in an unsupervised manner to group signals from MS data into spectra without relying on predictability of the in-source phenomenon. We additionally address a fundamental bottleneck in metabolomics, annotation of MS level signals, by incorporating indiscriminant MS/MS (idMS/MS) data implicitly: feature detection is performed on both MS and idMS/MS data, and feature-feature relationships are determined simultaneously from the MS and idMS/MS data. This approach facilitates identification of metabolites using in-source MS and/or idMS/MS spectra from a single experiment, reduces quantitative analytical variation compared to single-feature measures, and decreases false positive annotations of unpredictable phenomenon as novel compounds. This tool is released as a freely available R package, called RAMClustR, and is sufficiently versatile to group features from any chromatographic-spectrometric platform or feature-finding software.

Silver-doped titania nanoparticles (see image) in specific concentrations show a higher efficacy than pure silver nanoparticles towards the inhibition and annihilation of E. coli bacteria. The doped titania particles are synthesized via a sol–gel method. Antibacterial studies of the silver-doped titania particles in both a liquid-nutrient growth medium and on agar plates are shown; this approach may offer a simple low-cost method for fabricating antibacterial surfaces.

Due to their potential to accomplish complicated missions more effectively, UAV swarms have attracted a lot of attention lately. UAV swarm offers enhanced intelligence, improved coordination, increased flexibility, survivability, and reconfigurability. It is a multi-disciplinary system that necessitates a tight integration of several sub-systems, including optimal trajectory planning, localization, task coordination, etc. This review covers the important aspects of UAV swarms including swarm formation control, communication, swarm path planning, autonomy, coordination, and security. It additionally explores recent technical advancements in UAV swarm algorithms that have made the development of complex UAV swarm systems possible. This paper also provides insight into ethical aspects and the use cases of UAV swarms in various military, civilian, and entertainment applications. This paper is concluded by highlighting the potential future directions and challenges of UAV swarm technology and the need for more research and development to exploit their potential fully. Overall, this paper presents a comprehensive review of UAV swarm technology, addressing its potential for revolutionizing many fields and supporting advancements in the future.

It has been widely known that oxidative stress disrupts the balance between reactive oxygen species (ROS) and the antioxidant system in the body. During pregnancy, the physiological generation of ROS is involved in a variety of developmental processes ranging from oocyte maturation to luteolysis and embryo implantation. While abnormal overproduction of ROS disrupts these processes resulting in reproductive failure. In addition, excessive oxidative stress impairs maternal and placental functions and eventually results in fetal loss, IUGR, and gestational diabetes mellitus. Although some oxidative stress is inevitable during pregnancy, a balancing act between oxidant and antioxidant production is necessary at different stages of the pregnancy. The review aims to highlight the importance of maintaining oxidative and antioxidant balance throughout pregnancy. Furthermore, we highlight the role of oxidative stress in pregnancy-related diseases.

BACKGROUND: Increasing population and industrialization are continuously oppressing the existing energy resources and depleting the global fuel reservoirs. The elevated pollutions from the continuous consumption of non-renewable fossil fuels also seriously contaminating the surrounding environment. The use of alternate energy sources can be an environment-friendly solution to cope these challenges. Among the renewable energy sources biofuels (biomass-derived fuels) can serve as a better alternative to reduce the reliance on non-renewable fossil fuels. Bioethanol is one of the most widely consumed biofuels of today's world. OBJECTIVE: The main objective of this review is to highlight the significance of lignocellulosic biomass as a potential source for the production of biofuels like bioethanol, biodiesel or biogas. METHODS: We discuss the application of various methods for the bioconversion of lignocellulosic biomass to end products i.e. biofuels. The lignocellulosic biomass must be pretreated to disintegrate lignocellulosic complexes and to expose its chemical components for downstream processes. After pretreatment, the lignocellulosic biomass is then subjected to saccharification either via acidic or enzymatic hydrolysis. Thereafter, the monomeric sugars resulted from hydrolysis step are further processed into biofuel i.e. bioethanol, biodiesel or butanol etc. through the fermentation process. The fermented impure product is then purified through the distillation process to obtain pure biofuel. CONCLUSION: Renewable energy sources represent the potential fuel alternatives to overcome the global energy crises in a sustainable and eco-friendly manner. In future, biofuels may replenish the conventional non-renewable energy resources due to their renewability and several other advantages. Lignocellulosic biomass offers the most economical biomass to generate biofuels. However, extensive research is required for the commercial production of an efficient integrated biotransformation process for the production of lignocellulose mediated biofuels.

Electrospinning is a versatile strategy for creating nanofiber materials with various structures, which has broad application for a myriad of areas ranging from tissue engineering, energy harvesting, filtration and has become one of the most important academic and technical activities in the field of material science in recent years. In addition to playing a significant role in the construction of two-dimensional (2D) nanomaterials, electrospinning holds great promise as a robust method for producing three-dimensional (3D) aerogels and scaffolds. This article reviews and summarizes the recent advanced methods for fabricating electrospun three-dimensional nanofiber aerogels and scaffolds, including gas foaming, direct electrospinning of 3D nanofibrous scaffold, short nanofibers assembling into 3D aerogels/scaffolds, 3D printing, electrospray, origami and cell sheet engineering, centrifugal electrospinning, and other methods. Besides, intriguing formation process, crosslinking pathway, properties, and applications of 3D aerogels and scaffolds are also introduced. Taken together, these aerogels and scaffolds with various excellent features present tremendous potential in various fields.

Time series derived from simpler systems are single scale based and thus can be quantified by using traditional measures of entropy. However, times series derived from physical and biological systems are complex and show structures on multiple spatio-temporal scales. Traditional approaches of entropy based complexity measures fail to account for multiple scales inherent in these time series. Recently multi-scale entropy (MSE) method was introduced, which provide a way to measure complexity over a range of scales. MSE method uses sample entropy, a refinement of approximate entropy to quantify the complexity of time series. Nonstationarity, outliers and artifacts affect the sample entropy values because they change time series standard deviation and therefore, the value of similarity criterion. In this paper, we have used permutation entropy for quantifying the complexity, which is useful in the presence of dynamical and observational noise. We called this modified procedure multiscale permutation entropy (MPE). We observed that MPE is robust in presence of artifacts and robustly separates pathological and healthy groups

This paper provides a comprehensive review of the recent progress made in energy harvesting systems for wearable technology. An energy-harvesting system would be a useful strategy to address the issue of powering wearable electronic devices. This review presents different wearable energy harvesting methods based on the human body's heat and mechanical energy. To achieve continuous operation and high performance, reduce the requirement for external sources of energy, and enhance the lifespan of wearable devices, the invention of a sustainable and compatible power supply is required. In the human body, heat and mechanical motions are the two reliable and readily available energy sources. This study highlights the most recent research and advancements in energy harvesting from the human's mechanical motion and heat source. This article provides a detailed overview of the different wearable energy harvesters, their fabrication, working, and output results, which include piezoelectric, electrostatic, triboelectric, electromagnetic, thermoelectric, solar and hybrid wearable energy harvesters. The second part defines wearable energy harvesting using smart systems and artificial intelligence technology. Then the comparison of these energy harvesters is analyzed. Hybrid wearable energy harvesters provide the maximum power densities because they use two combined energy conversions. The advantages, limitations, and future perspectives of wearable energy harvesting technology are also discussed. Lastly, the wearable energy harvesters' market, and general developing and manufacturing cost of each wearable device is also presented functioning as a point of reference to comprehend the cost factors that are taken into account during the development and manufacturing processes.

Abstract Tailoring personalized cancer nanomedicines demands detailed understanding of the tumor microenvironment. In recent years, smart upconversion nanoparticles with the ability to exploit the unique characteristics of the tumor microenvironment for precise targeting have been designed. To activate upconversion nanoparticles, various bio‐physicochemical characteristics of the tumor microenvironment, namely, acidic pH, redox reactants, and hypoxia, are exploited. Stimuli‐responsive upconversion nanoparticles also utilize the excessive presence of adenosine triphosphate (ATP), riboflavin, and Zn 2+ in tumors. An overview of the design of stimulus‐responsive upconversion nanoparticles that precisely target and respond to tumors via targeting the tumor microenvironment and intracellular signals is provided. Detailed understanding of the tumor microenvironment and the personalized design of upconversion nanoparticles will result in more effective clinical translation.

Lysozymes are hydrolytic enzymes characterized by their ability to cleave the β-(1,4)-glycosidic bonds in peptidoglycan, a major structural component of the bacterial cell wall. This hydrolysis action compromises the integrity of the cell wall, causing the lysis of bacteria. For more than 80 years, its role of antibacterial defense in animals has been renowned, and it is also used as a preservative in foods and pharmaceuticals. In order to improve the antimicrobial efficacy of lysozyme, extensive research has been intended for its modifications. This manuscript reviews the natural antibiotic compound lysozyme with reference to its catalytic and non-catalytic mode of antibacterial action, lysozyme types, susceptibility and resistance of bacteria, modification of lysozyme molecules, and its applications in the food industry.

Nanosensors with high sensitivity utilize electrical, optical, and acoustic properties to improve the detection limits of analytes. The unique and exceptional properties of nanomaterials (large surface area to volume ratio, composition, charge, reactive sites, physical structure and potential) are exploited for sensing purposes. High-sensitivity in analyte recognition is achieved by preprocessing of samples, signal amplification and by applying different transduction approaches. In this review, types of signals produced and amplified by nanosensors (based on transducers) are presented, to sense exceptionally small concentrations of analytes present in a sample. The use of such nanosensors, sensitivity and selectivity can offer different advantages in biomedical applications like earlier detection of disease, toxins or biological threats and create significant improvements in clinical as well as environmental and industrial outcomes. The emerging discipline of nanotechnology at the boundary of life sciences and chemistry offers a wide range of prospects within a number of fields like fabrication and characterization of nanomaterials, supramolecular chemistry, targeted drug supply and early detection of disease related biomarkers.

Polycrystalline LaFe0.9Ni0.1O3 is prepared by the solid state reactions route. X-ray diffraction is used to analyse the phase purity of the compound. Impedance spectra of LaFe0.9Ni0.1O3 over the frequency range of 1?Hz to 10?MHz are investigated at different temperatures from 100 to 373?K. Two relaxation processes with different relaxation times are observed at each temperature. An equivalent circuit model (R1Q1) (R2Q2) is applied to explore the physical parameters associated with grains and grain boundaries. Frequency and temperature dependence of the relaxation processes and extracted parameters are discussed in terms of hopping between Fe+4 and Fe+3 and trap state scattering at grain boundaries. A change in conduction mechanism from variable range hopping to adiabatic small polaron hopping at 296?K is evident from these results. Traps are active below 296?K in capturing the charge.

Abstract Terahertz (THz) shielding becomes increasingly important with the growing development of THz electronics and devices. Primarily materials based on carbon nanostructures or polymer–carbon nanocomposites have been explored for this application. Herein, significantly enhanced THz shielding efficiencies for 2D titanium carbide (Ti 3 C 2 MXene) thin films with nanoscale THz metamaterials are presented. Nanoscale slot antenna arrays with strong resonances at certain frequencies enhance THz electromagnetic waves up to three orders of magnitude in transmission, which in turn enormously increases the shielding performance in combination with MXene films. Drop‐casting of a colloidal solution of MXene (a few micrograms of dry material) can produce an ultrathin film (several tens of nanometers in thickness) on a slot antenna array. Consequently, THz waves strongly localized in the near‐field regime by the slot antenna undergo enhanced absorption through the film with a magnified effective refractive index. Finally, the combination of an ultrathin MXene film and a nano‐metamaterial shows excellent shielding performance in the THz range.

Abstract Background Increasing antibiotic resistance continues to focus on research into the discovery of novel antimicrobial agents. Due to its antimicrobial and wound healing-promoting activity, metal nanoparticles have attracted attention for dermatological applications. This study is designed to investigate the scope and bactericidal potential of zinc ferrite nanoparticles (ZnFe 2 O 4 NPs), and the mechanism of anti-bacterial action along with cytocompatibility, hemocompatibility, and wound healing properties. Results ZnFe 2 O 4 NPs were synthesized via a modified co-precipitation method. Structure, size, morphology, and elemental compositions of ZnFe 2 O 4 NPs were analyzed using X-ray diffraction pattern, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. In PrestoBlue and live/dead assays, ZnFe 2 O 4 NPs exhibited dose-dependent cytotoxic effects on human dermal fibroblasts. In addition, the hemocompatibility assay revealed that the NPs do not significantly rupture red blood cells up to a dose of 1000 µg/mL. Bacterial live/dead imaging and zone of inhibition analysis demonstrated that ZnFe 2 O 4 NPs showed dose-dependent bactericidal activities in various strains of Gram-negative and Gram-positive bacteria. Interestingly, NPs showed antimicrobial activity through multiple mechanisms, such as cell membrane damage, protein leakage, and reactive oxygen species generation, and were more effective against gram-positive bacteria. Furthermore, in vitro scratch assay revealed that ZnFe 2 O 4 NPs improved cell migration and proliferation of cells, with noticeable shrinkage of the artificial wound model. Conclusions This study indicated that ZnFe 2 O 4 NPs have the potential to be used as a future antimicrobial and wound healing drug.