Application of Thionocarbamates in Copper Slag Flotation

Assessing the Impact of Retailer Disclosure on the Effectiveness of U.S. Meat and Poultry Recalls

This research study proposed a novel approach utilising AI models to predict the metallurgical performance of complex sulfide ore flotation. Five machine learning and artificial intelligence models were employed in this study, that is, Random Forest (RF), Artificial Neural Networks (ANN), Adaptive Neuro Fuzzy Interference System (ANFIS), Mamdani Fuzzy Logic (MFL) and Hybrid Neural Fuzzy Interference System (HyFIS). Sixty-two flotation tests were conducted on samples containing galena, chalcopyrite and sphalerite as the main valuable minerals, and pyrite as the main gangue mineral. Different variables were used as inputs in the AI studies including physiochemical and operational parameters. The flotation recovery of lead and copper and their corresponding grades in the bulk concentrate were the primary dependent variables (outputs). The input variables included the dosages of sodium cyanide (pyrite's depressant), sodium isopropyl xanthate (collector), zinc sulfate (sphalerite's depressant) and Methyl isobutyl carbinol (MIBC, frother); air flow rate; flotation time; and the speed of the impeller in the flotation cell, which is indicative of the energy input. For the purpose of AI model development, datasets were divided into two subsets. The first subset was primarily used for the training phase, and it comprised 80% of the total data. The second subset, consisting of 20% of the total data, was used for testing. The models’ performance was assessed using two main indicators: R-squared (R 2 ) for the proportion of explained variation and RMSE for the average prediction error. The Hybrid Neural Fuzzy Interference System demonstrated superior performance in predicting the recovery and grade of copper and lead, with R² and RMSE of 0.9895 and 1.069 for the training phase, respectively, whereas for the testing step the respective values were 0.9128 and 2.859.

BACKGROUND:The COVID-19 pandemic has spread rapidly across the world and has currently impacted most countries and territories globally. This study aimed to identify health-care determinants of mortality and recovery rates of COVID-19 and compare the efficiency of health systems in response to this pandemic.MATERIALS AND METHODS:A cross-sectional study was conducted using data obtained from the World Bank database, that provides free and open access to a comprehensive set of health- and socioeconomic-related data, by September 12, 2020. An adjusted linear regression model was applied to determine predictors of mortality (per 1 million population [MP]) and recovery rates (per 1 MP) in the included countries. One-way analysis of variance was applied to assess health systems' efficiency in response to COVID-19 pandemic using mortality and recovery rate (output variables) and current health expenditure (CHE) per capita (input variable).RESULTS:Globally, San Marino and Qatar had the highest mortality rate (1237/1 MP) and confirmed case rate (43,280/1 MP) until September 12, 2020, respectively. Iran had a higher mortality rate (273/1 MP vs. 214.5/1 MP) and lower recovery rate (4091.5/1 MP vs. 6477.2/1 MP) compared to countries with high CHE per capita. CHE per capita (standardized coefficient [SC] = 0.605, P < 0.001) and population aged 65 years and over as a percentage of total population (SC = −0.79, P < 0.001) significantly predicted recovered cases from COVID-19 in the included countries.CONCLUSION:This study revealed that countries with higher CHE per capita and higher proportion of older adults were more likely to have a higher recovery rate than those with lower ones. Furthermore, our study indicated that health systems with higher CHE per capita statistically had a greater efficiency in response to COVID-19 compared to those with lower CHE per capita. More attention to preventive strategies, early detection, and early intervention is suggested to improve the health system efficiency in controlling COVID-19 and its related mortalities worldwide.

Copper slag (CS), a prominent industrial by-product derived from copper sulphide concentrate smelting, contains valuable copper minerals. Mineralogical analysis revealed 0.56% arsenical copper/chalcopyrite, 1.29% chalcocite, 0.25% cuprite, and 0.24% bornite as the primary copper-bearing phases. Given the rapid depletion of readily exploitable copper resources, CS has emerged as a significant source for copper production. A systematic investigation was conducted to establish optimal operational parameters for classification, grinding, and flotation. This study encompassed diverse scenarios and laboratory tests, with a particular focus on reagent application, including types and consumption rates. The findings demonstrated that Na2S is used to activate copper oxide minerals that are difficult to recover after a period of grinding, increasing the recovery rate of CS from 53.92% to 87.58%, and the two-stage grinding process is beneficial for precise control of the particle size, considering both energy efficiency and mineral recovery rate. Upon conducting a comprehensive investigation into the closed-circuit flotation process for copper recovery from CS under optimal conditions, it was determined that the copper concentrate achieved a grade of 21.24% and a recovery rate of 36.31%. Additionally, the grade of copper in the flotation tailings was diminished to 0.20%. The synchronous enrichment of copper significantly curtails total emissions in pyrometallurgical processing, mitigating pollution from CS flotation tailings. This study offers a scientific foundation for sustainable CS tailing management, promoting resource recovery and reduced environmental impact.

The development of endoscopic transcervical catheterization (ETC) in the queen increases the interest in handling fresh and cryopreserved feline semen. The ETC requires a small volume of the insemination dose with a high concentration, not easily reached with the actual frozen technique in this species. Centrifugation is widely used to concentrate spermatozoa for several purposes, but this process is detrimental to spermatozoa. This study verified the effects of conventional and cushioned centrifugation on fresh and cryopreserved feline spermatozoa. To this, semen was collected from 20 toms, grouped in seven pools and diluted. After dilution, the pools were divided into two aliquots, the first used for centrifugation on fresh semen, and the second, after freezing, on cryopreserved semen. Centrifugation regimens were: conventional at 500×g, conventional at 1000×g, and cushioned (iodixanol) at 1000×g. The sperm recovery rate was calculated for the three centrifugation regimens, and sperm kinematics, membrane and acrosome integrity, and plasma membrane stability on viable spermatozoa were assessed as endpoints.The data reported in this study showed that the centrifugation at 500×g resulted in negligible effects on both fresh and cryopreserved spermatozoa, but the lower recovery rate (62.4 ± 3.1 % and 60.2 ± 1.6 %, respectively) underlines the loss of a large proportion of spermatozoa, unfavourable in a species with small total sperm ejaculated. On the other hand, the centrifugation at 1000×g improved the recovery rate (86.9 ± 4.3 % and 89.8 ± 2.4 % in fresh and cryopreserved samples, respectively), but was more deleterious for feline spermatozoa, especially in cryopreserved samples (i.e. total motility of 40.7 ± 5.4 % compared with 57.2 ± 9.8 % in cryopreserved uncentrifuged samples, P < 0.05), resulting in artificial insemination doses of lower quality. The recovery rate in cushioned centrifugation appeared less efficient, likely due to the small volume of feline samples, which makes difficult the separation of sperm pellet and cushioned fluid. Interestingly, in cryopreserved samples centrifuged at 1000×g the number of viable spermatozoa with membrane destabilization (31.3 ± 3.2 %) was greater than uncentrifuged (4.1 ± 0.7 %, P < 0.05) and those centrifuged at 500×g (9.8 ± 1.3 %, P < 0.05), suggesting modifications induced by the cryopreservation amplifies centrifugation sublethal damage on feline spermatozoa. Cushioned centrifugation on cryopreserved samples showed kinematics similar to uncentrifuged samples, but higher viable spermatozoa with membrane destabilization (37.4 ± 3.4 % vs 4.1 ± 0.7 %; P < 0.05). In felines, g-force is crucial for sperm recovery rate during centrifugation, with better results at 1000×g; on the other hand, greater g-forces could have a significant impact on the quality of feline insemination dose, especially in cryopreserved samples.

During a six-month period, on four separate occasions, six licensed day-care centers had cultures taken from environmental surfaces as well as the hands of children and teachers. Fecal coliforms were recovered from 64 (9.5%) of the 675 surfaces sampled. Recovery rate was not influenced by a center's socioeconomic status, time of year, or presence of children who were not toilet trained. Recovery rates did differ significantly in different areas, with the kitchen showing a relatively high recovery rate (19%), and toys and toilets showing remarkably low rates (2% and 4%). Centers with formal hand-washing procedures had lower recovery rates than those without such practices. We also demonstrated a high recovery rate from hands of staff (16%); 6% of children had positive cultures. Contamination of hands and classroom objects is a potential source for the transmission of enteric diseases for children in day-care centers. A program directed at reducing contamination would be important in preventing the spread of diarrheal illness.

Sperm cryopreservation is recommended to preserve male fertility for cancer patients or other medical conditions at risk of sperm decline. Whether motility and viability recovery rates vary depending on the medical conditions requiring cryopreservation is poorly known. We report here on the 24-year experience of our semen bank. Motility and viability recovery rates were evaluated in 1973 collections from patients with various medical conditions and 67 collections from donors, and the results were related to basal semen quality. Motility and viability recovery were highly related to basal semen quality and varied between cancer and non-cancer conditions, independently of the duration of cryopreservation and patient age. In samples with a sperm number below 2 × 106/mL, recovery rates approximated to zero. The highest recovery rates were found in donor collections. Cut-off values for the recovery of at least 1% motile spermatozoa were established based on initial semen quality. Our results indicate that the occurrence of any pathological or medical condition resulted in lower recovery rates with respect to donors, indicating that intrinsic sperm characteristics drive susceptibility to cryodamage. Established cut-off values for motility recovery can be useful for patient counseling as well as for ART laboratories to decide the type of procedure.

Carfilzomib Induces Acute Endothelial Dysfunction Which Correlates with the Occurrence of Cardiovascular Events

Particulate material recovered over an 18-month period from sediment traps deployed at a shallow-water nearshore Antarctic site was analysed for photosynthetic pigments, aliphatic hydrocarbons and fatty acids. All components showed a distinct seasonal variation, with high recovery rates during the summer open-water phytoplankton bloom and low rates under winter fast ice. The amount of trapped material differed between the two summers, indicating inter-annual variability of vertical flux associated with differences in the intensity of the summer phytoplankton bloom. Particulate material trapped in summer was dominated by that which originated in diatoms. High recoveries of chlorophyll a, fucoxanthin, n-C21:6 hydrocarbon, 20:5(n-3) fatty acid and shorter chain (C15–C24) aliphatic hydrocarbons all pointed to a significant summer flux of ungrazed diatoms. There were, however, also signals of zooplankton grazing activity (notably pyrophaeophorbide a), and the presence of C18:4(n-3) and C22:6(n-3) fatty acids suggested a small flux of material from flagellates and other sources. Longer chain n-alkanes (C25–C34) indicative of nanoplankton were detected all year, but there was no significant deposition of zooplankton material in any sample. The major recovery rate of photosynthetic pigments was in late summer (February to April), and the major grazing signal occurred after the peak of the summer diatom bloom. Most of the diatom bloom appeared to settle out from the water column without being grazed. The major seasonal contrast in the biochemistry of the trapped material was the dominance of the diatom signature in summer, and in winter the predominance (but at much lower recovery rates) of material from nanoplankton.

Modeling the hospitalization time of stroke patients at Abdul Wahab Sjahranie Hospital Samarinda using the Weibull Regression Model.

Background: This comprehensive study explores the prevalence of COVID-19 patients in Khyber Pakhtunkhwa, Pakistan, spanning from March 2020 to October 2022.Methodology: The research adopts a meticulous methodology, incorporating defined inclusion criteria and data collection from reputed sources such as government health agencies.A thorough quality assessment is applied to ensure the reliability of the included studies, and ethical considerations are upheld by using de-identified data from publicly available sources.The study provides a detailed analysis of COVID-19 cases, deaths, recoveries, and active cases in different divisions of Khyber Pakhtunkhwa, namely Peshawar, Mardan, Malakand, Hazara, Kohat, Bannu, and Dera Ismail Khan.Results: Analysis of COVID-19 data in Khyber Pakhtunkhwa (March 2020 to October 2022) revealed localized patterns.Peshawar Division, with 104,496 cases, showcased effective control measures (3.2% fatality, 96.7% recovery).With 24,772 patients, the Mardan Division showed lower death rates but similar recovery rates (3.5%, 96.5%).Malakand Division (38,832 cases) displayed varied fatality rates (2.1%) and recovery rates (97.9%).Hazara Division (26,986 cases) recorded lower fatality rates (2.1%) and generally higher recovery rates (97.9%).Kohat Division (15,090 cases) indicated moderate fatality rates (2.1%) and high recovery rates (97.9%).Bannu Division (6,250 cases) demonstrated a moderate impact with district-wise variations.Dera Ismail Khan Division (5,820 cases) faced challenges, notably a higher fatality rate (4.8%).Conclusion: This study underscores the necessity of region-specific data for tailoring effective pandemic responses, providing valuable insights for researchers, policymakers, and healthcare professionals engaged in managing and mitigating the impact of COVID-19 in Khyber Pakhtunkhwa.It highlights the ongoing importance of research efforts to continually refine public health strategies in response to the dynamic nature of the pandemic within different regions.

Due to freshwater scarcity, mineral flotation plants have been using alternative water resources including seawater together with water recycling, resulting in the accumulation of salts in process water. However, how salts affect the adsorption of xanthates on the surfaces of sulphide minerals and subsequent sulphide mineral flotation is unclear. To address the knowledge gap, this study investigated how NaCl affected the adsorption of potassium amyl xanthate (PAX) on chalcopyrite surface and chalcopyrite flotation. Cyclic voltammetry (CV) tests identified that NaCl increased the oxidation of PAX and its adsorption on chalcopyrite surface due to elevated ionic strength and electrical conductivity of water, facilitating charge transfer among PAX, chalcopyrite surface and oxygen. NaCl also increased chalcopyrite surface oxidation to produce more CuS, facilitating the formation of copper-xanthate complexes. Flotation tests identified that the increased adsorption of PAX by NaCl was only translated into improved true flotation of chalcopyrite at a low PAX concentration such as 50 ppm in NaCl solutions with low and medium concentrations (0.1 and 0.7 M, respectively). At a high PAX concentration such as 150 ppm, the coexistence of high concentrations of PAX and NaCl led to strong froth destabilisation, resulting in a dramatic reduction in water recovery and true flotation recovery of chalcopyrite. The findings from this study will be able to guide the flotation plants to maximise mineral flotation by choosing collector dosage based on the ionic strength of process water.

The objective of this study was to quantify the superovulatory response and embryo production of Brazilian Bergamasca sheep and to evaluate the link to the follicular condition before superovulatory treatment, as a reference for selection of donors with potential for superovulation. Follicular population of twenty-three sheep was evaluated by ultrasound during metestrus phase of the estrous cycle and divided into groups of low, medium and high follicular population. Subsequently, they were synchronized, superovulated with 133mg of pFSH, mated and subjected to embryo collection. The superovulatory response (9.0±3.3 vs 10.7±6.2 vs 13.8±7.1) and embryo production (4.0±3.8 vs 2.6±2.0 vs 1,8±4.0) were similar between groups (P&gt;0.05). There was a positive correlation between the number of follicles during the metestrus phase and the number of corpus luteum with premature regression (PLR) (0.52) and a negative correlation between the recovery rate and PLR (-0.44) (P&lt;0.05). The sheep that presented PLR had more follicles during metestrus (16.9±7.8 vs 12.7±3.2) and lower embryo recovery rate (38.8±29.3 vs 72.2±29.9) than those with functional CLs (P&lt;0.05). Follicular quantification during metestrus phases was unable to identify donors with high embryo production. Animals with PLR had a larger follicular population during metestrus and lower embryo recovery rate.

This study investigates the effects of sodium sulfate (Na2SO4) dosage, reaction temperature, and processing time on the structural decomposition of complex compounds in copper slag. Experimental results demonstrated that applying 20% Na2SO4 achieves an impressive decomposition rate of 89%, highlighting its effectiveness in liberating valuable metals from the slag matrix. The optimal temperature for maximizing fayalite decomposition is determined to be 900 °C, which significantly enhances reaction kinetics and efficiency. Furthermore, extending the reaction time to 90 min resulted in the highest observed decomposition efficiency. Subsequent leaching experiments in sulfuric acid confirmed that the liberated metal transitioned into the solution phase was very effective, ensuring high metal recovery rates. The treated samples demonstrated metal recovery rates of 97% for copper (Cu), 96% for iron (Fe), and 93% for zinc (Zn). In contrast, the untreated samples exhibited considerably lower recovery rates, with copper at 61%, iron at 59%, and zinc at 65%. Additionally, this approach mitigates filtration challenges by preventing the formation of silica gel. These findings provide key operational parameters for optimizing metal recovery from copper slag and establish a solid foundation for advancing sustainable and efficient resource extraction research.

The extraction of six fluoroquinolones from agricultural soils with different physicochemical characteristics (pH, texture and organic carbon content) has been investigated. Different solvents, consisting of hydroorganic mixtures, have been tested, and basic buffer solutions, with either acetonitrile or acetone, have proved to be suitable extraction solvents. Conventional mechanical shaking and microwave-assisted extraction techniques have been evaluated, and mechanical shaking has been selected. Recovery rates from freshly spiked (overnight) soils ranged from 65 to 90%, depending on the quinolone. No relevant dependence on soil characteristics has been observed. The effect of ageing on the extraction behaviour of fluoroquinolones has also been considered. In comparison with freshly spiked soils, extractions from residues aged for some months have resulted in about 20–25% lower recovery rates.