Effect of pH and exchangeable metals on phosphate adsorption by soils

A rapid and precise method for determination of surface charge density of soils was developed. The method involves saturating the negative and positive exchange sites with NH[subscript]4[superscript]+ and NO[subscript]3[superscript]-, respectively, removing the excess solution, and determining the ions on the exchange sites by steam distillation.;Studies on the effect of pH and exchangeable cations on P adsorption by six slightly acid, Iowa surface soils showed that the minimum adsorption occurred at a narrow pH range (ca. zpc, 4.5 to 5.5), below and above which phosphate adsorption increased sharply. The increase in P adsorption below this minimum adsorption was attributed to the effect of Al and Fe oxides, and the P adsorption above this pH range was attributed to the effect of exchangeable cations. This was confirmed by saturating the exchange sites with NH[subscript]4[superscript]+.;Adsorption of P by NH[subscript]4-saturated soils was less than that by untreated or water-leached soils when water was used as a matrix solution, and it was the greatest when 0.01 M CaCl[subscript]2 was the matrix solution. The amounts of NH[subscript]4[superscript]+ released to 0.01 M CaCl[subscript]2 confirmed the importance of exchangeable Ca in P adsorption. The amounts of P adsorbed by alkali metal-saturated soils decreased in the order of the following metals: K ≥ Na \u3e Rb \u3e Cs \u3e Li \u3e untreated soils when 0.01 M CaCl[subscript]2 was the matrix solution. The amounts of P adsorbed by alkaline earth metal-saturated soils were greater than those adsorbed by alkali metal-saturated soils. Regardless of the matrix solution used, the amounts of P adsorbed by the alkaline earth metal-saturated soils decreased in the order of the following metals: Ba \u3e Ca \u3e Mg \u3e Sr \u3e untreated soil. Saturation of soils with selected heavy metals increased P adsorption, and these increases were greater than those obtained for alkali metal- and alkaline earth metal-saturated soils. The amounts of P adsorbed were affected by the saturating heavy metal, with the following decreasing order: Pb \u3e Cu \u3e Zn \u3e Ni \u3e Cd \u3e Mn. Precipitation reactions were considered, but they were rejected for alkali metal- and alkaline earth metal-saturated soils, but they were possible for Cu-, Zn-, or Pb-saturated soils. Application of the Langmuir model showed that the adsorption maximum (X[subscript] m) and the affinity coefficient (k) are affected by the type of exchangeable metal and the matrix solution used

Optimized Scheduling of Repetitive Construction Projects under Uncertainty

Uncertainty is an inherent characteristic of construction projects. Neglecting uncertainties associated with different input parameters in the planning stage could well lead to misleading and/or unachievable project schedules. Many attempts have been made in the past to account for uncertainty during planning for construction projects and many tools and techniques were presented to facilitate modelling of such uncertainty. Some of the presented techniques are widely accepted and used frequently like Project Evaluation and Review Technique (PERT) and Monte Carlo Simulation, while others are more complicated and less popular, such as fuzzy set-based scheduling. Although accounting for uncertainty has been a topic of interest for more than four decades, it was rarely attempted to account for uncertainty when scheduling repetitive construction projects. Repetitive projects impose an additional challenge to the already complicated construction scheduling process that accounts for the need to maintain crew work continuity throughout project execution. This special characteristic necessitates producing scheduling techniques specifically suited to resource driven scheduling. Therefore, the main objective of this research is to produce a comprehensive scheduling, monitoring and control methodology for repetitive construction projects that is capable of accounting for uncertainties in various input parameters, while allowing for optimized acceleration and time-cost trade-off analysis. The proposed methodology encompasses three integrated models; Optimized Scheduling and Buffering Model, Monitoring and Dynamic Rescheduling Model and Acceleration Model. The first model presents an optimization technique that accounts for uncertainty in input parameters. It employs a modified dynamic programming technique that utilizes fuzzy set theory to model uncertainties. This model includes a schedule defuzzification tool and a buffering tool. The defuzzification tool converts the optimized fuzzy schedule into a deterministic one, and the buffering tool utilizes user’s required level of confidence in the produced schedule to build and insert time buffers, thus providing protection against anticipated delays affecting the project. The Monitoring and Dynamic Rescheduling Model capitalizes on the repetitive nature of these projects, by using actual progress on site to reduce uncertainty in the remaining part of the schedule. This model also tracks project progress through comparing the actual buffer consumption to the planned buffer consumption. The Acceleration Model presents an iterative unit based optimized acceleration procedure. It comprises a modified algorithm for identifying critical units of the project to accelerate. This model presents queuing criteria that accounts for uncertainty in additional cost of acceleration and for contractor’s judgment in relation to prioritizing critical units for acceleration. Moreover, this model offers six strategies for schedule acceleration and maintains crew work continuity. Together, the three developed models offer an integrated system that is capable of accounting for uncertainty in different variables through different project stages, aiming at helping managers keep repetitive construction projects on track. The presented optimization technique is automated in an Object Oriented program; coded in C# programming language. A number of case studies are analyzed and presented to demonstrate and validate the capabilities and features of the presented methodology

pH-Sensitive nanoparticles containing 5-fluorouracil and leucovorin as an improved anti-cancer option for colon cancer

Parenteral administration of chemotherapeutic drugs, 5-fluorouracil (5-FU) and leucovorin (LV), is commonly used to treat large bowel carcinomas such as colon cancer (CC) and colorectal carcinoma (CRC). Our study aims to design a novel nanoparticulate drug-delivery vehicle for oral use capable of colon-specific release. A modified double-emulsion solvent evaporation method was used in the preparation of pH-responsive Eudargit S100 polymeric nanoparticles, loaded with 5-FU/LV combination (5-FU/LV-loaded Eudargit S100 NPs). Our optimized drug-loaded NP showed a pH-responsive drug release and exhibited significantly more cytotoxic actions in cancer-cell lines than free drugs. These findings open the way for conducting clinical trials for colon malignancies treated with nanoparticles

A REVIEW OF ANTIBIOTIC USED IN SUSPECTED EARLY-ONSET NEONATAL SEPSIS FROM MALAYSIAN PERSPECTIVE: WHICH ONES TO CHOOSE AND HOW LONG TO GIVE?

Objective: Suspected early-onset sepsis is a common diagnosis among neonates which warrants admission to the neonatal intensive care unit. Prolonged empiric antibiotic is the biggest concern and treatment duration is still controversial. Antimicrobial stewardship (AMS) program promotes early antibiotic de-escalation to reduce unnecessary antibiotic exposure and its implementation in the intensive care setting seems to be feasible. The primary objective of this review was to compare the existing guidelines and review the literature regarding choice and duration of empiric antibiotic in managing suspected early-onset neonatal sepsis.Methods: Two Malaysian Ministry of Health guidelines were compared with guidelines from America (n=1), Australia (n=1), and United Kingdom (n=2). The literature search was conducted from January to June 2017 through open access journal and databases available at the author's institution library (EBSCOHost, Ovid and Science Direct).Results: All guidelines recommended similar antibiotics range and suggested to review treatment at 36– 72 h post antibiotic exposure. A total of 113 abstracts and full articles were identified, and only 11 full-text articles published in English were related to the subject of interest. All studies show differences either in study design, choice of antibiotics, treatment duration or outcome measures; thus, a meta-analysis was not possible to be conducted.Conclusion: From this review, we found the potential to performed early empiric antibiotic de-escalation especially in clinically well-appearance neonates, and it is best to customize our guidelines based on local evidence which justify the need for more local research in this area

Atypical presentation of COVID-19 in a diabetic patient with malaria-like symptoms: case report

Since the emergence of the coronavirus (COVID-19) pandemic beginning in China in 2019, all health workers have faced a difficult  challenge. One challenge is a clinical picture in some cases, where the presenting symptoms do not fit with the usual pattern. In this report, we present a case whose initial symptoms were headache, dizziness, and vomiting suggesting malaria bearing in mind that the patient was from Sudan, where there is a high incidence of malaria. These unusual symptoms may be attributed to the presence of the receptor ACE2, in various body systems. The mild pathological course may be related to the patient’s age and the fact that diabetic patients are less likely to develop lung injury, hence the absence of respiratory symptoms. We recommend that physicians are alert to the variety of different presenting features of COVID-19 and test with Polymerase Chain Reaction (PCR) whenever there is doubt

Predictors of Acute Diarrhoea among Hospitalized Children in Gaza Governorates: A Case-Control Study

This study aims to determine the predictors of acute diarrhoea among hospitalized children in the Gaza Governorates. The case-control design included 140 children (70 cases and 70 controls) in a stratified cluster sample from Naser Medical Complex and Alnasser Pediatric Hospital. An interview questionnaire was used, and face and content validations were performed. Multiple logistic regression was used for the multivariate analysis of risk factors of diarrhoea in children aged less than five years. Results showed a significant association between diarrhoea and family income, residence, complementary feeding, and age of weaning (p<0.05). Children living in villages had lower odds of having diarrhoea by 53.2% than children living in cities. Children of families with incomes between US$485 and 620 had lower odds of having diarrhoea by 80.8$ 485. Moreover, children who did not receive complementary feeding had lower odds of having diarrhoea by 59.0%. We found that, for one month increase in weaning age, the odds of diarrhoea decreased by 1.06 times (adjusted OR=1.05, 95% CI 1.0180- 1.100). The study concludes that urban residence, lower family income, complementary feeding, and lower age of weaning are risk factors of diarrhoea among children aged less than five years in the Gaza Strip. The results of the study suggest that children of low-income families and those who were not naturally breastfed may warrant more attention for prevention and/or treatment of diarrhoea

Physical pegylation enhances the cytotoxicity of 5-fluorouracil-loaded PLGA And PCL nanoparticles.

Purpose : The main goal of this study is to evaluate the impact of physical incorporation of polyethylene glycol (PEG) into 5-fluorouracil (5-FU)-loaded polymeric nanoparticles (NPs). METHODS: The 5-FU-loaded NPs were prepared utilizing a simple double emulsion method using polycaprolactone (PCL) and polylactic-co-glycolic acid (PLGA) with or without PEG 6000. The surface charge, particle size, and shape of NPs were evaluated by standard procedures. Both Fourier Transform Infrared Spectroscopy and X-ray diffraction spectra of the 5-FU loaded NPs were compared against the pure 5-FU. The in vitro release profile of 5-FU from the NPs was monitored by the dialysis tubing method. Cell death and apoptosis induction in response to 5-FU NP exposure were measured by MTT and Annexin-V/7-amino-actinomycin D (7-AAD) assays, respectively, in Daoy, HepG2, and HT-29 cancer cell lines. RESULTS: The 5-FU loaded NPs were found to be spherical in shape with size ranging between 176±6.7 and 253.9±8.6 nm. The zeta potential varied between -7.13± 0.13 and -27.06±3.18 mV, and the entrapment efficiency was between 31.96% and 74.09%. The in vitro release of the drug followed a two-phase mode characterized by rapid release in the first 8 hrs followed by a period of slow release up to 72 hrs with composition-based variable extents. Cells exposed to NPs demonstrated a significant cell death which correlated with the ratio of PEG in the formulations in Daoy and HepG2 cells but not in HT-29 cells. Formulations (F1-F3) significantly induced early apoptosis in HT-29 cell lines. CONCLUSION: The physical PEGylation significantly enhanced the entrapment and loading efficiencies of 5-FU into NPs formulated with PLGA and PCL. It also fostered the in vitro cytotoxicity of 5-FU-loaded NPs in both Daoy and HepG2 cells. Induction of early apoptosis was confirmed for some of the formulations

COVID-19 clinical presentations: the modern mimic of other conditions

The coronavirus pandemic (COVID-19) has placed enormous challenges on the health sector. Diagnosis is one of these challenges, where a clinical presentation may suggest a disease other than COVID-19. In this review we describe many presentations unrelated to the respiratory system. The ACE2 receptor is present in a wide variety of body tissues and it appears that this may be a link with the clinical pathology. To find these data we searched the major academic research engines, Google Scholar, and Pubmed, as well as the most recent case reports and original research published in specialized journals. An awareness of these uncommon presentations helps health workers to recognize and treat the disease early and appropriately. Keywords: COVID-19, coronavirus, pandemic, ACE2, unusual symptoms, revie

pH-sensitive nanoparticles containing 5-fluorouracil and leucovorin as an improved anti-cancer option for colon cancer.

Parenteral administration of chemotherapeutic drugs, 5-fluorouracil (5-FU) and leucovorin (LV), is commonly used to treat large bowel carcinomas such as colon cancer (CC) and colorectal carcinoma (CRC). Our study aims to design a novel nanoparticulate drug-delivery vehicle for oral use capable of colon-specific release. A modified double-emulsion solvent evaporation method was used in the preparation of pH-responsive Eudargit S100 polymeric nanoparticles, loaded with 5-FU/LV combination (5-FU/LV-loaded Eudargit S100 NPs). Our optimized drug-loaded NP showed a pH-responsive drug release and exhibited significantly more cytotoxic actions in cancer-cell lines than free drugs. These findings open the way for conducting clinical trials for colon malignancies treated with nanoparticles