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The advancement of reverse osmosis (RO) technology in water treatment has brought about significant purification benefits. However, the presence of scales poses obstacles to the long-term effectiveness and reliability of RO systems, therefore, the use of antiscalants has emerged as an effective solution. This comprehensive review explores various aspects of scale formations, including their characteristics and prevalence. It delves into detailed understanding of crystal nucleation inhibition, dispersion of crystal growth, threshold inhibition, and inhibition mechanisms, shedding light on the intricate processes involved in successful scale prevention. In addition, this review also explores the realm of antiscalants, uncovering their exceptional potential, mechanisms of action, and game-changing value in RO systems. It takes a thorough evaluation approach to different antiscalant substances, ranging from traditional inhibitors like phosphonates and synthetic polymers to more sustainable and greener inhibitors including biopolymers as promising candidates. The review assesses their efficacy, optimal dosage requirements, and compatibility with varying water pH levels. Moreover, the review highlights the utility of fluorescent-labeled antiscalants to elucidate the mechanisms underlying scale formation and inhibition, revealing the role of “nanodust” particles as primary heterogeneous nucleation centers, and the antiscalants’ role in disrupting the scale formation process. Limitations of current antiscalants and practical challenges, such as antiscalant-induced membrane biofouling, are also highlighted. Furthermore, the review explores options for removing antiscalants from the resulting concentrates. By setting the stage for future antiscalant research, this review offers innovative solutions to overcome existing challenges and achieve higher efficiency in RO systems, emphasizing the important role of synthetic and green polymers as antiscalants.Graphical abstract

Magnetic copper ferrite nanoparticles, CuFe2O4-NPs (CFN) were synthesized via a facile sol–gel method for the effective removal of 4-nitrophenol (4-NP) and indigo carmine dye (IC) as typical hazardous organic pollutants from wastewater. The texture, morphology, and composition of the synthesized CuFe2O4 NPs were thoroughly explored by various physicochemical techniques. Various factors affecting the dye adsorption including the effect of adsorbent mass, contact time, pH, initial IC concentration, and temperatures were investigated to determine the optimum conditions for IC dye removal. The impact of diverse species and other coexisting dyes on the adsorption capacity of CFN was investigated. Five adsorption isotherms were investigated using two-parameters (Tekman, Langmuir, and Freundlich) and three-parameters (Sips, and Redlich-Peterson) models. CFN exhibited a maximum adsorption capacity of 57.4 mg/g according to the Sips model, with optimal conditions observed at pH 3, a contact time of 90 min, and an adsorbent mass of 0.1 g. Thermodynamic data revealed both the endothermic nature of dye removal and the random arrangement of dye molecules onto CFN adsorbent. The IC dye elimination mechanism was elucidated. Furthermore, the CFN-catalyzed reduction of 4-nitrophenol by NaBH4 followed first-order kinetics at a high rate of 0.4365 min−1, reflecting the high catalytic capacity of the synthesized CFN. The magnetic features, cost-effectiveness, recyclability, and high adsorption and catalytic activities towards IC dye and 4-NP removals made the synthesized CFN a promising catalyst for wastewater remediation.

Background: Because of lack of good evidence supporting laparoscopic approach for complicated appendicitis, we carried out this study to evaluate efficacy of laparoscopic appendectomy (LA) in management of patients with complicated appendicitis. Materials and Methods: This study was carried out in Surgical Department, Minia University, Egypt involving 214 patients underwent appendectomy for complicated appendicitis over three years. 132 patients underwent LA and remaining 82 patients underwent OA. Parameters studied included operating time, return to oral feeding, postoperative pain, wound infection, intra-abdominal abscess, duration of abdominal drainage and hospital stay. Results: There were four conversions, two due to extensive cecal adhesions and two due to friable appendix. LA took longer time to perform (p = 0.0002) but with less use of analgesics (p < 0.0001), shorter hospital stay (p < 0.0001), shorter duration of abdominal drainage (p < 0.0001) and lower incidence of wound infection (p = 0.0005). Nine patients in LA and seven patients in OA group developed intra-abdominal abscess treated successfully with sonographic guided percutaneous drainage. Postoperative ileus was recorded in two patients in LA group and three patients in OA group, chest infection in one patient in OA group, hernia in one patient in LA and fecal fistula was present in one patient in OA. Overall complications were significantly lower in laparoscopy group and managed conservatively with no mortality in either group. Conclusions: LA in complicated appendicitis is feasible and safe with lower incidence of complications than OA and should be the initial choice for all patients with complicated appendicitis.

Laparoscopic cholecystectomy (LC) is one of the first laparoscopic procedures performed by surgical trainees. This study aims to determine preoperative and/or intraoperative predictors of difficult LC and to compare complications of LC performed by trainees with that performed by trained surgeons. A cohort of 180 consecutive patients with cholelithiasis who underwent LC was analyzed. We used univariate and binary logistic regression analyses to predict factors associated with difficult LC. We compared the rate of complications of LCs performed by trainees and that performed by trained surgeons using Pearson’s chi-square test. Patients with impacted stone in the neck of the gallbladder (GB) (OR, 5.0; 95% CI, 1.59–15.77), with adhesions in the Triangle of Calot (OR, 2.9; 95% CI, 1.27–6.83), or with GB rupture (OR, 3.4; 95% CI, 1.02–11.41) were more likely to experience difficult LC. There was no difference between trainees and trained surgeons in the rate of cystic artery injury (p=.144) or GB rupture (p=.097). However, operative time of LCs performed by trained surgeons was significantly shorter (median, 45 min; IQR, 30–70 min) compared with the surgical trainees’ operative time (60 min; IQR, 50–90 min). Surgical trainees can perform difficult LC safely under supervision with no increase in complications albeit with mild increase in operative time.

Digital imaging using conventional camera, mobile phone camera, or computer scanner can be a convenient and low-cost approach for the highly sensitive assessment of hexavalent chromium in natural and waste waters. An aliquot sample containing Cr(VI) is reacted with diphenylcarbazide to yield a characteristic violet color. Image analysis of the violet-colored product gave the red, green, and blue (RGB) intensities that are converted into ten uniform and non-uniform color spaces and two color difference parameters, which are used and compared here, for the first time, as analytical signaling tools for the assessment of hexavalent chromium. Many of the acquired signals displayed outstanding analytical performance and statistically surpassed the regularly used RGB signals and competed well with signals of a sophisticated Shimadzu 1650 PC spectrophotometer. The sensitivity and simplicity and low cost of this strategy make it an outstanding competitor for commercial hexavalent chromium analyzers and advanced spectrophotometers.

Simple, low-cost, and sensitive methods for the assessment of hexavalent chromium as an important environmental pollutant are highly desirable, especially under resource-limited settings. Therefore, herein we propose an original approach for the simple, low-cost, selective, and extremely sensitive assessment of Cr(VI) utilizing its catalysis of the micellar sensitized o- dianisidine (DA)–hydrogen peroxide reaction. The initial rate of the amended reaction is monitored by tracing the oxidation product, either by a digital camera video recording or spectrophotometrically at 440 nm, for 120 s from mixing the reactants. The optimized reaction conditions were 5 mmol L −1 DA, 0.6 mol L −1 H 2 O 2 , 2.0 v/v% Tween 20, and 10 mmol L −1 chloroacetate buffer (pH 4.5 ± 0.1), at 30 °C. The linear calibration graph extends to 90.0 ng mL −1 Cr(VI) with detection limits (3S b ) of 0.8 and 1.0 ng mL −1 , for the video recording and spectrophotometric procedures, respectively. The amended method was successfully applied to the assessment of Cr(IV) in natural and polluted industrial wastewaters. The analytical data were in excellent statistical harmony with those of the standard ETAAS method. The proposed method is two orders of magnitude more sensitive than the diphenylcarbazide standard spectrophotometric method. Graphical abstract

The determination of stoichiometric ratios and stability constants of metal–ligand complexes is of great importance for physical, chemical, biochemical, and environmental studies and often require relatively expensive and sophisticated instruments. Herein, we introduce a simple, accurate, and low-cost method for determining these parameters by a conventional digital camera. The stoichiometric ratios and stability constants of iron complexes of 1,10-phenanthroline, 2,4,6-Tris(2-pyridyl)-s-triazine, and salicylate were determined, as model examples, using the molar ratio and the continuous variation methods. Digital images of solutions with various metal–ligand ratios were captured and analyzed, and the Y xy color absorbance and the Δ E LUV color difference parameters were used as convenient analytical signals that favorably compete with conventional spectrophotometric signals. For the three studied iron complexes, the results of stoichiometric ratios and stability constants obtained from digital images were in excellent agreement with the spectrophotometric and the previously reported literature’s data.

Abstract Objective Effective postoperative pain control reduces postoperative morbidity. In this study, we investigated the effects of intrathecal morphine, ketamine, and their combination with bupivacaine for postoperative analgesia in major abdominal cancer surgery. Study Design Prospective, randomized, double-blind. Setting Academic medical center. Patients and Methods Ninety ASA I–III patients age 30 to 50 years were divided randomly into three groups: the morphine group (group M) received 10 mg of hyperbaric bupivacaine 0.5% in 2 mL volume and 0.3 mg morphine in 1 mL volume intrathecally. The ketamine group (group K) received 0.1 mg/kg ketamine in 1 mL volume instead of morphine. The morphine + ketamine group (group K + M) received both 0.3 mg morphine and 0.1 mg/kg ketamine in 1 mL volume intrathecally. Postoperative total morphine consumption, first request of analgesia, visual analog score (VAS), and side effects were recorded. Results Total PCA morphine was significantly decreased in group M + K compared with groups M and K. Time to first request of analgesia was prolonged in groups M and M + K compared with group K (P < 0.001). VAS in group M + K was reduced from two to 24 hours, and in group M from 12 and 18 hours postoperation compared with group K, with an overall good analgesia in the three groups. Sedation was significantly higher in group M + K compared with group M until six hours postoperation. No other side effects were observed. Conclusions Adding intrathecal ketamine 0.1 mg/kg to morphine 0.3 mg in patients who underwent major abdominal cancer surgery reduced the total postoperative morphine consumption in comparison with either drug alone, with an overall good postoperative analgesia in all groups, with no side effects apart from sedation.

Filter paper-based optical sensors (FPOS) offer rapid and sensitive quantification of analytes. Herein we report, a simple, sensitive, selective and low-cost FPOS for Th(IV) determination. Filter paper strips, impregnated with Morin reagent are reacted with Th(IV) yielding an intense yellow complex whose RGB (red/green/blue) color intensities made the basis of the assessment. A plot of the blue channel color absorbance versus Th(IV) concentration was linear up to 4.0 µg mL− 1 with a detection limit of 0.1 µg mL− 1. The proposed method was accurate, precise and reliable for analyzing complex certified rock samples in excellent compliance with the certified values.

A simple, selective and highly sensitive spectrophotometric method has been developed for mercury determination utilizing its catalytic effect on the isoniazid-hexacyanoferrate (II) reaction. The paper presents for the first time (1) the catalytic effect of Hg (I) on the cited ligand substitution reactions and (2) the activating effect of thiourea on the behavior of mercury. The reaction was monitored spectrophotometrically at 423 nm using the initial rate method. The optimized reaction conditions were 5.0 mmol L −1 hexacyanoferrate (II), 0.5 mmol L −1 isoniazid, 150 mmol L −1 citrate buffer (pH 3.30 ± 0.05), and 0.2 mmol L −1 thiourea, at 50°C. Linear calibration graphs were obtained for 1–100 and 1–55 µg L −1 with detection limits, based on the 3S b -criterion, of 1.2 and 1.8 µg L −1 of Hg (II) and Hg (I), respectively. The method was conveniently applied to samples of wastewaters, inactivated vaccines, and frozen Bass fish fillet, without any prior separation or preconcentration.