Towards classification and comprehensive analysis of AI-based COVID-19 diagnostic techniques: A survey.

The unpredictable pandemic came to light at the end of December 2019, known as the novel coronavirus, also termed COVID-19, identified by the World Health Organization (WHO). The virus first originated in Wuhan (China) and rapidly affected most of the world's population. This outbreak's impact is experienced worldwide because it causes high mortality risk, many cases, and economic falls. Around the globe, the total number of cases and deaths reported till November 12, 2022, were >600 million and 6.6 million, respectively. During the period of COVID-19, several diverse diagnostic techniques have been proposed. This work presents a systematic review of COVID-19 diagnostic techniques in response to such acts. Initially, these techniques are classified into different categories based on their working principle and detection modalities, i.e. chest X-ray imaging, cough sound or respiratory patterns, RT-PCR, antigen testing, and antibody testing. After that, a comparative analysis is performed to evaluate these techniques' efficacy which may help to determine an optimum solution for a particular scenario. The findings of the proposed work show that Artificial Intelligence plays a vital role in developing COVID-19 diagnostic techniques which support the healthcare system. The related work can be a footprint for all the researchers, available under a single umbrella. Additionally, all the techniques are long-lasting and can be used for future pandemics.

An improved technology for monitoring groundwater flow velocity and direction in fractured rock system based on colloidal particles motion.

The colloidal borescope, using colloidal particle motion, is used to monitor the flow velocities and directions of groundwater. It integrates advanced techniques such as microscopy, high-speed photography, and big data computing and enjoys high sensitivity at the micron level. However, In the same well, the groundwater flow velocity monitored by colloidal hole mirror is varies greatly from that obtained by conventional hydrogeological monitoring, such as pumping test. In order to solve this problem, the stability catcher and stratified packer are designed to control the interference of the vertical flow in drilling, and to monitor the flow velocity and direction of groundwater velocity at the target aquifer and target fracture. Five wells with different aquifers and different groundwater types were selected for monitoring in south-central China. The instantaneous velocity and direction are converted into east-west component and north-south component, the average velocity and direction is calculated according to the time of 10 min, and the particle trajectory diagram is established. Based on these results, it proposed a concept of cumulative flow velocity. Using curve-fitting equations, the limits of cumulative flow velocities as the monitoring time tends to infinity were then calculated as the actual flow velocities of the groundwater. The permeability coefficient of aquifer is calculated by using the fissure ratio of aquifer, hydraulic slope and flow velocity, and compared with the permeability coefficient obtained by pumping test. The results are as follows: (1) The variation coefficient of the instantaneous flow velocity measured at the same depth in the same well at different times is greater than that of the time average flow velocity and greater than that of the cumulative flow velocity. The variation coefficient of the actual velocity is the smallest, indicating that the risk of using the actual flow velocity is lower. (2) The variation coefficient of the flow rate monitored at different depths in the same well is mainly controlled by the properties of the aquifer. The more uniform water storage space in the aquifer, the smaller the variation coefficient. (3) The comparison between the permeability coefficient obtained by monitoring and the permeability coefficient obtained by pumping test shows that the flow of structural fissure water controlled by planar fissure is more surface flow, and the results are consistent. When the groundwater flow is controlled by pores and solution gaps, the flow channel is complicated, which is easy to produce turbulent flow, and the result consistency is poor. (4) According to different research accuracy requirements, different monitoring and calculation methods can be selected for different aquifers and groundwater types. Researches show that, the permeability coefficient calculated for the actual flow velocity in well DR01 is the same as that calculated for the pumping test. The aquifer characteristics reflected by the coefficient of variation of the actual flow velocity in the same aquifer are more realistic. The pumping test method obtains the comprehensive parameters of a certain aquifer, and this method can be used to monitor a certain fissure. In this paper, the new technology developed for monitoring, and the new algorithm established for data processing, can accurately obtain the flow velocity and direction of groundwater, using capsule hole mirror monitoring method. The key parameters of hydrogeology can be obtained by using one well, which can reduce the time and cost input and improve the work efficiency.

Dissolved organic matter (DOM) is independently stratified in thermally stratified water bodies.

Thermal stratification often occurs in deep-water bodies, including oceans, lakes, and reservoirs. Dissolved organic matter (DOM) plays a critical role in regulating the dynamics of aquatic food webs and water quality in aquatic ecosystems. In the past, thermal stratification boundaries have been sometimes used exclusively to analyze the vertical distribution of DOM in thermally stratified water bodies. However, the validity of this practice has been challenged. Currently, there is limited understanding of the formation mechanism and stratification of the vertical distribution of DOM in thermally stratified water bodies, which hinders the analysis of the interactions between DOM and vertical aquatic ecological factors. To address this gap, we conducted a comprehensive study to extensively collect the vertical distribution of DOM in thermally stratified water bodies and identify the primary factors influencing this distribution. We found that DOM was independently stratified in thermally stratified water bodies (including two cases in unstratified water bodies), and that the formation mechanisms and statuses of DOM stratification were different from those of thermal stratification. The boundaries and numbers of DOM stratification were generally inconsistent with those of thermal stratification. Therefore, it is more accurate to divide DOM into different layers according to its own vertical profile, and analyze DOM characteristics of each layer based on its own stratification instead of thermal stratification. This study sheds light on the relationship between DOM and thermal stratification and provides a novel approach for analyzing DOM vertical distribution characteristics and their impact on aquatic ecosystems. This finding also holds significant implications for the design and implementation of environmental management programs aimed at preserving the health and functionality of aquatic ecosystems.

Enhancement of Antibacterial Properties, Surface Morphology and In Vitro Bioactivity of Hydroxyapatite-Zinc Oxide Nanocomposite Coating by Electrophoretic Deposition Technique.

To develop medical-grade stainless-steel 316L implants that are biocompatible, non-toxic and antibacterial, such implants need to be coated with biomaterials to meet the current demanding properties of biomedical materials. Hydroxyapatite (HA) is commonly used as a bone implant coating due to its excellent biocompatible properties. Zinc oxide (ZnO) nanoparticles are added to HA to increase its antibacterial and cohesion properties. The specimens were made of a stainless-steel grade 316 substrate coated with HA-ZnO using the electrophoretic deposition technique (EPD), and were subsequently characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), stylus profilometry, electrochemical corrosion testing and Fourier transform infrared (FTIR) spectroscopy. Additionally, cross-hatch tests, cell viability assays, antibacterial assessment and in vitro activity tests in simulated body fluid (SBF) were performed. The results showed that the HA-ZnO coating was uniform and resistant to corrosion in an acceptable range. FTIR confirmed the presence of HA-ZnO compositions, and the in vitro response and adhesion were in accordance with standard requirements for biomedical materials. Cell viability confirmed the viability of cells in an acceptable range (>70%). In addition, the antibacterial activity of ZnO was confirmed on Staphylococcus aureus. Thus, the HA-ZnO samples are recommended for biomedical applications.

Exploring the potential of late permian aggregate resources for utilization in engineering structures through geotechnical, geochemical and petrographic analyses.

The China-Pakistan Economic Corridor (CPEC) is an ongoing mega-construction project in Pakistan that necessitates further exploration of new natural resources of aggregate to facilitate the extensive construction. Therefore, the Late Permian strata of Chhidru and Wargal Limestone for aggregates resources were envisaged to evaluate their optimal way of construction usage through detailed geotechnical, geochemical, and petrographic analyses. Geotechnical analysis was performed under BS and ASTM standards with the help of employing different laboratory tests. A simple regression analysis was employed to ascertain mutual correlations between physical parameters. Based on the petrographic analysis, the Wargal Limestone is classified into mudstones and wackestone, and Chhidru Formation is categorized into wackestone and floatstone microfacies, both containing primary constituents of calcite and bioclasts. The geochemical analysis revealed that the Wargal Limestone and Chhidru Formation encompass calcium oxide (CaO) as the dominant mineral content. These analyses also depicted that the Wargal Limestone aggregates bear no vulnerability to alkali-aggregate reactions (AAR), whereas the Chhidru Formation tends to be susceptible to AAR and deleterious. Moreover, the coefficient of determination and strength characteristics, for instance, unconfined compressive strength and point load test were found inversely associated with bioclast concentrations and directly linked to calcite contents. Based on the geotechnical, petrographic, and geochemical analyses, the Wargal Limestone proved to be a significant potential source for both small and large-scale construction projects, such as CPEC, but the Chhidru Formation aggregates should be used with extra caution due to high silica content.

Nesting Biology and Ecology of a Resin Bee, Megachile cephalotes (Megachilidae: Hymenoptera).

We report the nesting biology and ecology of Megachile cephalotes Smith, 1853 for the first time in Pakistan. Wooden and bamboo trap nests were deployed at three different locations in Bahawalpur district, Pakistan, from January 2020 to May 2021. A total of 242 nests of M. cephalotes were occupied in all three locations with the maximum abundance in the Cholistan Institute of Desert Studies. Megachile cephalotes remained active from March to September (the spring and summer seasons). In a nest, females made 7-8 brood cells each having a length of 1.2-2.3 cm. Plant resin was used to construct cells and mud or animal dung to plug the nest entrance. A vestibular cell was also made between the outermost brood cell and the nest entrance that ranged from 1.4 to 2.5 cm in length. No intercalary cells were observed in the nests. The males took 65.3 days to become adults, while the females took 74.78 days. The sex ratio was significantly biased toward females in all three locations. Grewia asiatica was the predominant pollen grain species found in the brood cells. Megachile cephalotes were observed collecting resin from Acacia nilotica, Prosopis juliflora, and Moringa oleifera. Three cleptoparasites of this species were also recorded: Euaspis carbonaria, Coelioxys sp., and Anthrax sp. This study set up a background to encourage new studies on artificial nesting and provides tools for proper biodiversity management and conservation.

A Visual Servoing Scheme for Autonomous Aquaculture Net Pens Inspection Using ROV.

Aquaculture net pens inspection and monitoring are important to ensure net stability and fish health in the fish farms. Remotely operated vehicles (ROVs) offer a low-cost and sophisticated solution for the regular inspection of the underwater fish net pens due to their ability of visual sensing and autonomy in a challenging and dynamic aquaculture environment. In this paper, we report the integration of an ROV with a visual servoing scheme for regular inspection and tracking of the net pens. We propose a vision-based positioning scheme that consists of an object detector, a pose generator, and a closed-loop controller. The system employs a modular approach that first utilizes two easily identifiable parallel ropes attached to the net for image processing through traditional computer vision methods. Second, the reference positions of the ROV relative to the net plane are extracted on the basis of a vision triangulation method. Third, a closed-loop control law is employed to instruct the vehicle to traverse from top to bottom along the net plane to inspect its status. The proposed vision-based scheme has been implemented and tested both through simulations and field experiments. The extensive experimental results have allowed the assessment of the performance of the scheme that resulted satisfactorily and can supplement the traditional aquaculture net pens inspection and tracking systems.

Environmental-friendly extraction of Peepal (Ficus Religiosa) bark-based reddish brown tannin natural dye for silk coloration.

The present study aims to extract a natural reddish brown colorant from Peepal (Ficus religiosa) for silk dyeing using the microwave radiation process (MW). The colorant was isolated in aqueous and acidic media, and MW treatment for 1, 2, 3, 4, and 5 min has been given to both fabric and extract to observe changes in color intensity. The dye variables have been optimized, and for sustainable shade making process with good fastness, 1.0-5.0 g/100 mL of sustainable chemical and bio-mordants has been employed. It has been found that after microwave treatment for 3 min, under selected conditions, the irradiated aqueous extract has given high color intensity onto silk fabric. The utilization of 3% of Al, 4% of Fe, and 2% of tannic acid (T.A.) as pre chemical mordant whereas 4% of Al, 4% of Fe, and 3% of tannic acid as post chemical mordant have given good color characteristics. In comparison, 4% of acacia and 3% of turmeric and pomegranate while 3% of acacia and turmeric and 4% of pomegranate extracts as post-bio-mordant have given excellent color characteristics. It is concluded that MW treatment has an excellent sustainable efficacy to isolate colorant from Peepal bark for silk dyeing, whereas the inclusion of bio-mordants has not only made the process more sustainable and environmental friendly but also best K/S, and L*a*b* values have been acquired.

Effect of different fish feeds on water quality and growth of crucian carp (Carassius carassius) in the presence and absence of prometryn.

Few data are available regarding comprehensive or quantitative assessment of fish feed considering both the environmental and feeding impacts. Aiming to fill the gap, an experimental study to investigate the effects of three fish feeds on concentrations of nutrients and crucian carp (Carassius carassius) growth was conducted in laboratory aquariums in the presence and absence of prometryn. Results showed that weight gain rates of crucian carp treated with Tong Wei (TW) feed were 106.3% and 2.0% higher than that of Zhong Shan (ZS) and Zhong Liang (ZL) feeds, a possible explanation was that the quality of protein in TW feed was highest as evidenced by the protein efficiency ratios. Meanwhile, TW feed posed relatively lighter effects on water qualities (between ZL and ZS). Prometryn significantly inhibited the growth of crucian carp and thus affected concentrations of nutrients in water indirectly. The relationships between weight gain rates of fish and concentrations of nutrients in water (R2 = 0.929-0.990) were developed. In sum, this study suggested that it is realizable to obtain better fish growth performance with lesser degrading effects on water qualities by producing and selecting appropriate feed regardless of prometryn existence, and the developed equations could be used as a basis for future studies.

Plant communities exhibit low resource partitioning for pollinator guilds under sub-tropical conditions of Pakistan.

Assessment of resource partitioning in pollinators at a particular place can be used to conserve plant communities by minimizing their inter-specific competition. Current study was conducted to investigate the occurrence of this phenomenon among plant communities under sub-tropical conditions for the first time in Pakistan. We considered the entire available flowering plant and floral visitor communities in the study area-Lal Suhanra forest of Bahawalpur, Pakistan- along with different variations among them based on morphology, color and symmetry (functional groups) i.e. four functional groups among insects and nine among plants. Weekly floral visitor censuses were conducted during spring season -from the first week of March to the fourth week of May 2018. Thirty individuals of each plant species -in bloom- were observed for floral visitors in each census. Plant species with different floral shapes, colors and symmetry did not show any significant resource partitioning. The Non-metric multidimensional scaling analysis followed by one-way ANOSIM test showed non- significant differences among all the pair of floral shapes, colors (except white and yellow) and symmetry (R-value < 0.168). However, SIMPER test suggested that flies were the most common group that contributed more towards within group similarities of different floral shapes (19 to 21% similarity), colors (16 to 30%) and symmetry (19%) followed by long-tongue bees i.e. 14 to 21%, 9 to 19% and 18%, respectively. Our results suggest that plant communities under sub-tropical conditions of Pakistan exhibit a generalist pollination system with no significant resource partitioning in pollinator species. Therefore, plant communities may have high competition for pollinator species which exhibits fewer implications of species loss on overall pollination process. Our study provides the basis for understanding the partitioning of pollinator guilds under sub-tropical conditions. Future studies should focus on functional traits in more detail at the community and the population scales for their possible impact on resource partitioning.

Effects of fish feed addition scenarios with prometryn on Microcystis aeruginosa growth and water qualities.

The number of undesirable environmental impacts of fish feed has been reported widely. Although repeated fish feed exposures are more prospective to occur in water, previous studies were mostly conducted as a single exposure of fish feed. In order to fill these gaps, a 40 days incubator experiment was conducted to explore the effects of fish feed addition scenarios during the lag phase with prometryn on both Microcystis aeruginosa growth and concentrations of nutrients. The maximum algae densities in groups of single exposure were 6.0-26.2% and 8.8-74.4% higher than those in groups of double and triple exposures, respectively (P < 0.05). At the beginning of the experiment, concentrations of nutrients in groups with different feed exposure scenarios were significantly different. The pattern of nutrient limitation showed a transformation from phosphorus limitation to nitrogen limitation generally. Furthermore, the average inhibition rates of algae by prometryn in the case of a single fish feed exposure were 4.6-9.4% lower than those under double exposures, and 22.0-26.8% lower than those under triple exposures (P < 0.05). In addition, algae growth rates have been developed as a function of concentrations of consumed nutrients (R2 = 0.410-0.932). Based on the above results, we concluded that in terms of limiting algae growth multiple low-dosage additions of fish feed were considered as a better addition pattern. By optimizing feed addition scenarios, there is considerable potential to increase the environmental sustainability of aquaculture.

Understanding youth participation to volunteer for child rights.

BACKGROUND: Today, Pakistan has the highest percentage of young people in its history, who can become champions of child rights through channelizing their energy. Voices for Children's Aspirations and Needs (VCAN) student society at the University of Lahore is one such student body, working to promote child rights and eliminate violence against children. OBJECTIVES: The study identifies factors contributing to young people's motivation to join VCAN student society working for children's rights and influence their participation in activities, along with attitudinal shift. The current study also attempts to find out effective mediums to engage youth in volunteering activities for the prevention of violence against children. PARTICIPANTS: Sample (N = 40) was selected through purposive sampling from the VCAN Student Society at the University of Lahore. METHOD: The data were collected through a questionnaire developed by the researchers (α = 0.86). Collected data were analyzed by finding descriptive statistics (mean, percentage and frequency) and paired samplet-test using statistics software, SPSS, version 21.0. RESULTS: Motivation for joining student society included wanting to work for the betterment of children (57.5 %) and to volunteer for the prevention of violence against children (47.5 %). There was a statistically significant difference (t=-4.16, p < .001) in the perception of participants about child rights before and after joining the society. Factors such as lack of required knowledge, unclear roles, and contrast between expected role and skillset (45.0 %, 42.5 %, and 40.0 % respectively) discouraged youth participation. 37.5 % of the participants considered WhatsApp as an extremely effective way to engage youth whereas 32.5 % reported Facebook as an extremely effective medium for the same purpose. CONCLUSION: Student societies provide a great platform for students to be active for a social cause. Educational institutions should encourage and facilitate youth participation for such causes.

Characterization of PTFE Film on 316L Stainless Steel Deposited through Spin Coating and Its Anticorrosion Performance in Multi Acidic Mediums.

Polytetrafluoroethylene (PTFE) was coated on 316L stainless steel (SS) substrate through a spin coating technique to enhance its corrosion resistance properties in hydrochloric acid (HCl) and nitric acid (HNO3) medium. Scanning electron microscopy (SEM) revealed the morphology of the coated and uncoated substrates and showed a uniform and crack-free PTFE coating on 316L SS substrate, while a damaged surface with thick corrosive layers was observed after the electrochemical test on the uncoated sample. However, an increased concentration of HCl and HNO3 slightly affected the surface morphology by covering the corrosive pits. An atomic force microscope (AFM) showed that the average surface roughness on 316L SS and PTFE coating was 26.3 nm and 24.1 nm, respectively. Energy dispersive x-ray spectroscopy (EDS) was used for the compositional analysis, which confirmed the presence of PTFE coating. The micro Vickers hardness test was used to estimate the hardness of 316L SS and PTFE-coated substrate, while the scratch test was used to study the adhesion properties of PTFE coating on 316L SS. The anticorrosion measurements of 316L SS and PTFE-coated substrates were made in various HCl and HNO3 solutions by using the electrochemical corrosion test. A comparison of the corrosion performance of PTFE-coated substrate with that of bare 316L SS substrate in HCl medium showed a protection efficiency (PE) of 96.7%, and in the case of HNO3 medium, the PE was 99.02%, by slightly shifting the corrosion potential of the coated sample towards the anodic direction.

Using GIS tools to detect the land use/land cover changes during forty years in Lodhran District of Pakistan.

Land use/land cover (LULC) change has serious implications for environment as LULC is directly related to land degradation over a period of time and results in many changes in the environment. Monitoring the locations and distributions of LULC changes is important for establishing links between regulatory actions, policy decisions, and subsequent LULC activities. The normalized difference vegetation index (NDVI) has the potential ability to identify the vegetation features of various eco-regions and provides valuable information as a remote sensing tool in studying vegetation phenology cycles. Similarly, the normalized difference built-up index (NDBI) may be used for quoting built-up land. This study aims to detect the pattern of LULC, NDBI, and NDVI change in Lodhran district, Pakistan, from the Landsat images taken over 40 years, considering four major LULC types as follows: water bodies, built-up area, bare soil, and vegetation. Supervised classification was applied to detect LULC changes observed over Lodhran district as it explains the maximum likelihood algorithm in software ERDAS imagine 15. Most farmers (46.6%) perceived that there have been extreme changes of onset of temperature, planting season, and less precipitation amount in Lodhran district in the last few years. In 2017, building areas increased (4.3%) as compared to 1977. NDVI values for Lodhran district were highest in 1977 (up to + 0.86) and lowest in 1997 (up to - 0.33). Overall accuracy for classification was 86% for 1977, 85% for 1987, 86% for 1997, 88% for 2007, and 95% for 2017. LULC change with soil types, temperature, and NDVI, NDBI, and slope classes was common in the study area, and the conversions of bare soil into vegetation area and built-up area were major changes in the past 40 years in Lodhran district. Lodhran district faces rising temperatures, less irrigation water, and low rainfall. Farmers are aware of these climatic changes and are adapting strategies to cope with the effects but require support from government.

Activities of Select Enzymes Involved in Insecticide Resistance in Spinosad-Resistant and -Susceptible Strains of Musca domestica (Diptera: Muscidae).

A Musca domestica L. strain collected from Pakistan has recently been shown to be resistant to spinosad; however, there is scarce information about the mechanism of resistance. For this reason, we explored whether a metabolic-based mechanism was responsible by analyzing the activities of the metabolic detoxifying enzymes, carboxylesterases, glutathione S-transferases, and mixed-function oxidases, in both a spinosad-selected (Spin-SEL) strain of M. domestica and a susceptible counterpart (Lab-susceptible). The results revealed that both strains were statistically at par in terms of enzyme activities. The activity of carboxylesterases in the Lab-susceptible strain was 78.17 ± 3.06 in comparison to 79.16 ± 3.31 nmol min-1 mg-1 in the Spin-SEL strain. The activity of mixed-function oxidases was 51.58 ± 4.20 in the Lab-susceptible strain, whereas 54.33 ± 4.08 pmol min-1 mg-1 was recorded in the Spin-SEL strain. The activity of glutathione S-transferases was 86.50 ± 4.59 (Lab-susceptible) and 90.33 ± 2.81 nmol min-1 mg-1 (Spin-SEL). These results revealed that the studied enzymes might not be responsible for spinosad resistance in the studied strain of M. domestica. Therefore, studies should be extended to find out other possible mechanisms of spinosad resistance.

Study of land cover/land use changes using RS and GIS: a case study of Multan district, Pakistan.

Water and land both are limited resources. Current management strategies are facing multiple challenges to meet food security of an increasing population in numerous South Asian countries, including Pakistan. The study of land cover/land use changes (LCLUC) and land surface temperature (LST) is important as both provide critical information for policymaking of natural resources. We spatially examined LCLU and LST changes in district Multan, Pakistan, and its impacts on vegetation cover and water during 1988 to 2017. The LCLUC indicate that rice and sugarcane had less volatility of change in comparison with both cotton and wheat. Producer's accuracy (PA) is the map accuracy (the producer of map), but user's accuracy (UA) is the accuracy from the point of view of a map user, not the map maker. Average overall producer's and user's accuracy for the region was 85.7% and 87.7% for Rabi (winter) and Kharif (summer) seasons, respectively. The results of this study showed that 'built-up area' increased with 7.2% of all the classes during 1988 to 2017 in the Multan district. Anthropogenic activities decreased the vegetation, leading to an increase in LST in study area. Changes on LCLU and LST during the last 30 years have shown that vegetation pattern has changed and temperature has increased in the Multan district.

DNA interaction and photodynamic antitumor activity of transition metal mono-hydroxyl corrole.

A series of iron(III), manganese(III) and copper(III) mono-hydroxyl corrole complexes had been prepared and well characterized by UV-vis, 1H NMR, 19F NMR and HR-MS. These metallocorroles may bind to CT-DNA through external binding mode. Metallocorrole Fe-2c exhibited significant phototoxicity and low toxicity toward A549 tumor cells. While manganese (III) and copper (III) corroles showed hypotoxicity to A549, MCF-7 and HepG-2 tumor cells, whether under dark or illumination conditions. All tested metallocorroles exhibited non-toxicity to human normal cells (GES-1) with or without irradiation at 625 nm. Cell cycle analysis indicated that metallocorrole Fe-2c arrested the cell cycle at G2/M phase and increased the Sub-G1 phase in A549 cell lines. It was mainly localized at mitochondria and could significantly reduce mitochondrial membrane potential after photodynamic treatment, which would further induce tumor cell apoptosis.

Resistance Status to Deltamethrin, Permethrin, and Temephos Along With Preliminary Resistance Mechanism in Aedes aegypti (Diptera: Culicidae) From Punjab, Pakistan.

The use of insecticides such as deltamethrin, permethrin, and temephos has been a primary tool to manage Aedes aegypti (Linnaeus) in Punjab province, Pakistan; however, recent reports of control failure necessitate monitoring insecticide resistance. For this reason, we evaluated 12 field strains of Ae. aegypti from Punjab for resistance against deltamethrin, permethrin, and temephos along with underlying resistance mechanisms. For deltamethrin, high level of resistance was observed in Rawalpindi, Faisalabad, Sheikhupura, Lahore, Pattoki, and Kasur strains (RRLC50 > 10-fold); moderate level of resistance in Sargodha, Gujranwala, and Sialkot strains (RRLC50 = 5- to 10-fold), and low level of resistance in Okara, Multan, and Sahiwal strains (RRLC50 < 5-fold). In the case of permethrin, high level of resistance was found in all the field strains, except the Okara strain that exhibited moderate resistance. For temephos, five field strains, viz. Faisalabad, Rawalpindi, Kasur, Lahore, and Gujranwala, showed high level of resistance; five strains, viz. Sheikhupura, Sialkot, Pattoki, Sahiwal, and Okara, showed moderate resistance, and two strains from Multan and Sargodha showed low resistance to temephos. Synergism bioassays implementing piperonyl butoxide and S,S,S-tributylphosphorotrithioate exhibited a nonsignificant effect on synergizing toxicity of deltamethrin and permethrin in all field strains except the Lahore strain, suggesting the possible role of target-site resistance mechanism. However, both synergists had a significant effect on synergizing toxicity of temephos in all field strains, suggesting the possibility of metabolic-based mechanism of insecticide resistance. In conclusion, the study confirmed the presence of resistance to deltamethrin, permethrin, and temephos in the studied field strains of Ae. aegypti from Punjab, Pakistan.

Reactive Cobalt⁻Oxo Complexes of Tetrapyrrolic Macrocycles and N-based Ligand in Oxidative Transformation Reactions.

High-valent cobalt⁻oxo complexes are reactive transient intermediates in a number of oxidative transformation processes e.g., water oxidation and oxygen atom transfer reactions. Studies of cobalt⁻oxo complexes are very important for understanding the mechanism of the oxygen evolution center in natural photosynthesis, and helpful to replicate enzyme catalysis in artificial systems. This review summarizes the development of identification of high-valent cobalt⁻oxo species of tetrapyrrolic macrocycles and N-based ligands in oxidation of organic substrates, water oxidation reaction and in the preparation of cobalt⁻oxo complexes.

Trichlorfon and spinosad resistance survey and preliminary determination of the resistance mechanism in Pakistani field strains of Bactrocera dorsalis.

The use of insecticides has been a primary tool to manage Bactrocera dorsalis in Pakistan; however, recent reports of field control failures necessitate mapping out the insecticide resistance problem. Therefore, eight field strains from Pakistan, were evaluated for their resistance against trichlorfon and spinosad. Compared with a reference strain, six field strains showed high levels of resistance to trichlorfon, while two field strains expressed intermediate resistance. In case of spinosad, five field strains fell in the susceptible range, whereas, the rest of the strains represented minor resistance. Correlation analysis between LD50 values of trichlorfon and spinosad of all the field strains revealed non-significant association, suggesting the possibility of lack of cross-resistance between both insecticides. Synergism bioassays implementing S,S,S-tributylphosphorotrithioate (DEF) and piperonyl butoxide (PBO) revealed that the LD50 values of trichlorfon in the presence of either DEF or PBO in seven field strains were significantly reduced. However, DEF and PBO had a non-significant effect on synergizing spinosad toxicity. The results revealed resistance to trichlorfon in field strains of B. dorsalis, which might be metabolic-based. Absence or minor resistance to spinosad and lack of cross-resistance to trichlorfon, suggest that spinosad could be a potential candidate for managing B. dorsalis.