A highly sensitive colorimetric assessment of hexavalent chromium using a digital camera.

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 H2O2, 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 (3Sb) 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.

Effect of Intrathecally Administered Ketamine, Morphine, and Their Combination Added to Bupivacaine in Patients Undergoing Major Abdominal Cancer Surgery a Randomized, Double-Blind Study.

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.

A Highly Sensitive and Selective Catalytic Determination of Mercury in Environmental Samples.

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 3Sb-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.

Advances in ultrasound-assisted synthesis of photocatalysts and sonophotocatalytic processes: A review.

Water pollution and the global energy crisis are two significant challenges that the world is facing today. Ultrasound-assisted synthesis offers a simple, versatile, and green synthetic tool for nanostructured materials that are often unavailable by traditional synthesis. Furthermore, the integration of ultrasound and photocatalysis has recently received considerable interest due to its potential for environmental remediation as a low-cost, efficient, and environmentally friendly technique. The underlying principles and mechanisms of sonophotocatalysis, including enhanced mass transfer, improved catalyst-pollutant interaction, and reactive species production have been discussed. Various organic pollutants as dyes, pharmaceuticals, pesticides, and emerging organic pollutants are targeted based on their improved sonophotocatalytic degradation efficiency. Additionally, the important factors affecting sonophotocatalytic processes and the advantages and challenges associated with these processes are discussed. Overall, this review provides a comprehensive understanding of sono-assisted synthesis and photocatalytic degradation of organic pollutants and prospects for progress in this field.

Nanomaterials-modified reverse osmosis membranes: a comprehensive review.

Because of its great efficiency and widespread application, reverse osmosis (RO) is a popular tool for water desalination and purification. However, traditional RO membranes have a short lifespan due to membrane fouling, deterioration, decreased salt rejection rate, and the low water flux with aging. As a result, membrane modification has received a lot of attention recently, with nanomaterials being extensively researched to improve membrane efficacy and lifespan. Herein, we present an in-depth analysis of recent advances of RO membranes modification utilizing nanomaterials. An overview of the various nanomaterials used for membrane modification, including metal oxides, zeolites, and carbon nanomaterials, is provided. The synthesis techniques and methods of integrating these nanomaterials into RO membranes are also discussed. The impacts of nanomaterial change on the performance of RO membranes are addressed. The underlying mechanisms responsible for RO membrane enhancements by nanomaterials, such as improved surface hydrophilicity, reduced membrane fouling via surface repulsion and anti-adhesion properties, and enhanced structural stability, are discussed. Furthermore, the review provides a critical analysis of the challenges and limitations associated with the use of nanomaterials to modify RO membranes. Overall, this review provides valuable insights into the modification of RO membranes with nanomaterials, providing a full grasp of the benefits, challenges, and future prospects of this challenging topic.

A novel layered double hydroxide-based ternary nanocomposite for the effective photocatalytic degradation of rhodamine B.

Photocatalytic degradation of organic pollutants is a green and effective route of wastewater treatment. Zinc oxide was initially used for this purpose; however, calcined zinc/chromium layered double hydroxide (ZnCr-LDO) and cadmium sulfide quantum dots (CdSQDs)-based nanocomposites proved as superior alternatives. Herein, we report a green sonochemical method for the sol-gel fabrication of novel CdSQDs@ZnCr-LDO/ZnO ternary nanocomposite that exhibited exceptional photocatalytic activity for the degradation of rhodamine B dye (RhB), in wastewaters, under UV-A-irradiation. The features of the ternary nanocomposite were investigated using various physicochemical techniques, including XRD, SEM, TEM, EDX, XPS, BET, zeta potential, DRS, and PL measurements. The RhB dye % removal was 38.02, 40.2, and 98% using pristine ZnO, ZnCr-LDO and the ternary CdSQDs@ZnCr-LDO/ZnO-based nanomaterials, respectively, reflecting the superior ternary nanocomposite's photocatalytic activity that made it an excellent competitor to commonly reported photocatalysts. Additionally, an investigation was carried out to determine the key reactive species in the photocatalytic degradation of RhB, considering both scavenger's type and concentration. The prevailing mechanism was found to be the reductive photodegradation pathway. Furthermore, several models were utilized to describe the kinetics of photocatalytic performance of the ternary nanocomposite and a typical Z-scheme type-II photocatalytic heterojunction mechanism was inferred.

Current and emerging trends of inorganic, organic and eco-friendly corrosion inhibitors.

Effective corrosion control strategies are highly desired to reduce the fate of corrosion. One widely adopted approach is the use of corrosion inhibitors, which can significantly mitigate the detrimental effects of corrosion. This systematic review provides a thorough analysis of corrosion inhibitors, including both inorganic and organic compounds. It explores the inhibition mechanisms, highlighting the remarkable inhibitive efficiency of organic compounds attributed to the presence of heteroatoms and conjugated π-electron systems. The review presents case studies and investigations of corrosion inhibitors, shedding light on their performance and application potential. Moreover, it compares the efficacy, compatibility, and sustainability of emerging environmentally friendly corrosion inhibitors, including biopolymers from natural resources as promising candidates. The review also highlights the potential of synergistic impacts between mixed corrosion inhibitors, particularly organic/organic systems, as a viable and advantageous choice for applications in challenging processing environments. The evaluation of inhibitors is discussed, encompassing weight loss (WL) analysis, electrochemical analysis, surface analysis, and quantum mechanical calculations. The review also discusses the thermodynamics and isotherms related to corrosion inhibition, further improving the understanding of inhibitor's behavior and mechanisms. This review serves as a valuable resource for researchers, engineers, and practitioners involved in corrosion control, offering insights and future directions for effective and environmentally friendly corrosion inhibition strategies.

Unveiling the photocatalytic potential of graphitic carbon nitride (g-C3N4): a state-of-the-art review.

Graphitic carbon nitride (g-C3N4)-based materials have emerged as promising photocatalysts due to their unique band structure, excellent stability, and environmental friendliness. This review provides a comprehensive and in-depth analysis of the current state of research on g-C3N4-based photocatalysts. The review summarizes several strategies to improve the photocatalytic performance of pristine g-C3N4, e.g., by creating heterojunctions, doping with non-metallic and metallic materials, co-catalyst loading, tuning catalyst morphology, metal deposition, and nitrogen-defect engineering. The review also highlights the various characterization techniques employed to elucidate the structural and physicochemical features of g-C3N4-based catalysts, as well as their applications of in photocatalytic degradation and hydrogen production, emphasizing their remarkable performance in pollutants' removal and clean energy generation. Furthermore, this review article investigates the effect of operational parameters on the catalytic activity and efficiency of g-C3N4-based catalysts, shedding light on the key factors that influence their performance. The review also provides insights into the photocatalytic pathways and reaction mechanisms involving g-C3N4 based photocatalysts. The review also identifies the research gaps and challenges in the field and presents prospects for the development and utilization of g-C3N4-based photocatalysts. Overall, this comprehensive review provides valuable insights into the synthesis, characterization, applications, and prospects of g-C3N4-based photocatalysts, offering guidance for future research and technological advancements in this rapidly growing field.

Laparoscopic appendectomy in complicated appendicitis: Is it safe?

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.

The use of chitosan-based composites for environmental remediation: A review.

The presence of hazardous pollutants in water sources as a result of industrial activities is a major environmental challenge that impedes the availability of safe drinking water. Adsorptive and photocatalytic degradative removal of various pollutants in wastewater have been recognized as cost-effective and energy-efficient strategies. In addition to its biological activity, chitosan and its derivatives are considered as promising materials for the removal of various pollutants. The abundance of hydroxyl and amino groups in the chitosan macromolecular structure results in a variety of concurrent pollutant's adsorption mechanisms. Furthermore, adding chitosan to photocatalysts increases the mass transfer while decreasing both the band gap energy and the amount of intermediates produced during photocatalytic processes, improving the overall photocatalytic efficiency. Herein, we have reviewed the current design and preparation of chitosan and its composites, as well as their applications for the removal of various pollutants by adsorption and photocatalysis processes. Effects of operating variables such as the pH, catalyst mass, contact time, light wavelength, initial pollutant's concentration, and catalyst recyclability, are discussed. Various kinetic and isotherm models are presented to elucidate the rates, and mechanisms of pollutant's removal, onto chitosan-based composites, and several case studies are presented. Additionally, the antibacterial activity of chitosan-based composites has been discussed. This review aims to provide a comprehensive and up-to-date overview of the applications of chitosan-based composites in wastewater treatment and put forward new insights for the development of highly effective chitosan-based adsorbents and photocatalysts. Finally, the main challenges and future directions in the field are discussed.

Fouling in reverse osmosis membranes: monitoring, characterization, mitigation strategies and future directions.

Water scarcity has been a global challenge for many countries over the past decades, and as a result, reverse osmosis (RO) has emerged as a promising and cost-effective tool for water desalination and wastewater remediation. Currently, RO accounts for >65% of the worldwide desalination capacity; however, membrane fouling is a major issue in RO processes. Fouling reduces the membrane's lifespan and permeability, while also increases the operating pressure and chemical cleaning frequency. Overall, fouling reduces the quality and quantity of desalinated water, and thus hinders the sustainable application of RO membranes by disturbing its efficacy and economic aspects. Fouling arises from various physicochemical interactions between water pollutants and membrane materials leading to foulants' accumulation onto the membrane surfaces and/or inside the membrane pores. The current review illustrates the main types of particulates, organic, inorganic and biological foulants, along with the major factors affecting its formation and development. Moreover, the currently used monitoring methods, characterization techniques and the potential mitigation strategies of membrane fouling are reviewed. Further, the still-faced challenges and the future research on RO membrane fouling are addressed.

Synthesis, characterization and application of chitosan/graphene oxide/copper ferrite nanocomposite for the adsorptive removal of anionic and cationic dyes from wastewater.

The increased discharge of water pollutants drives the development of new and effective wastewater remediation methods. Herein, a magnetic nanocomposite of chitosan-graphene oxide (GO) decorated with copper ferrite (MCSGO) was synthesized under ultrasound agitation and applied to the effective removal of Safranin O (SAF) and indigo carmine (IC) dyes from wastewater. The structural, magnetic, and physicochemical features of the as-prepared MCSGO nanocomposite have been thoroughly investigated using various characterization techniques. The operational parameters such as MCSGO mass, contact time, pH, and initial dye concentration were investigated. The effects of diverse coexisting species on both dye elimination processes were examined. The experimental results demonstrated that the adsorption capacity of MCSGO nanocomposite for IC and SAF was 112.6 and 66.15 mg g-1, respectively. Five different adsorption isotherms were investigated using two-parameter (Langmuir, Tekman, and Freundlich) and three-parameter (Sips, and Redlich-Peterson) models. Thermodynamic studies revealed that the elimination of both dyes on MCSGO nanocomposite was endothermic and spontaneous, with anionic and cationic dye molecules randomly arranged onto the adsorbent nanoparticles. Moreover, the mechanism of dye elimination was deduced. Furthermore, even after five cycles of adsorption and desorption, the as-prepared nanocomposite showed no significant loss in the dye removal efficiency, indicating that it has superior stability and recycling potential.

Recent progress in semiconductor/graphene photocatalysts: synthesis, photocatalytic applications, and challenges.

The presence of an increasing number of organic pollutants in water now poses serious risks to both human health and ecological systems. Many of these pollutants are persistent and non-biodegradable. The contamination of fresh water by harmful substances has compelled researchers to develop innovative, efficient, and cost-effective water remediation techniques and materials. Thus, photocatalysis has long been recognized as a promising approach to tackle both environmental remediation and the energy crisis. However, semiconductor photocatalysts frequently suffer from defects such as photo-generated charge carrier recombination, poor visible light response, and slow surface reaction kinetics, which can be remedied by modifications with appropriate co-catalysts. Therefore, graphene and its derivatives have widely been used as supports for semiconductors and photocatalysts due to their distinctive optical, physicochemical, and electrical features. This critical review addresses the current progress in the design and synthesis of graphene/semiconductor photocatalysts, as well as their use in photocatalytic degradation of organic pollutants and hydrogen production. Several influencing parameters are addressed, including pH, photocatalyst loading, initial pollutant concentration, light wavelength, and oxidizing species, all of which could have a significant impact on the rate of organic pollutant's degradation. Furthermore, the recyclability of the catalyst and its photocatalytic activity mechanisms are thoroughly discussed. Numerous case studies are systematically presented. Moreover, future prospects and major challenges are highlighted.

Determination of acid dissociation constants of Alizarin Red S, Methyl Orange, Bromothymol Blue and Bromophenol Blue using a digital camera.

Acid dissociation constants (pK a) are important parameters for the characterization of organic and inorganic compounds. They play a crucial role in different physical, chemical, and biological studies. Herein, we introduce a new approach for the determination of acid dissociation constant based on digital image analysis using a low-cost, precise, accurate, sensitive, and portable home-made, camera-based platform. Digital images of Alizarin Red S, Bromophenol Blue, Bromothymol Blue, and Methyl Orange solutions were captured at various pH values. The captured images were analysed to obtain the RGB (Red, Green, and Blue) colour intensities that are used to calculate the RGB colour absorbances. The pK a values were calculated from the RGB colour absorbance-pH relationship using graphical and mathematical methods, and with the aid of DATAN software. For the four studied dyes, the results obtained from digital image analysis were in excellent agreement with the data of sophisticated spectrophotometers and the previously reported literature data.

Digital imaging devices as sensors for iron determination.

Portable, sensitive and cost-effective sensors represent an unmet need, especially in resource-limited settings and locally deprived communities. Digital imaging devices can fill the gap. Thus, we have tested a desktop scanner, a digital camera and a smartphone to determine iron using three standard colour reactions. Images of reacting solutions were analysed to obtain the RGB (red, green and blue) non-uniform colour space parameters. To improve the calibration linearity, sensitivity, and detection limit, we converted the RGB intensities into six uniform colour space values and two colour differences attributes. The converted signals surpassed the RGB signals and compared well with reference spectrophotometric signals. The simplicity and sensitivity of this approach make digital imaging devices as excellent competitors to field-monitoring instruments and sophisticated spectrophotometers. Our approach was successfully applied to the assessment of iron in Nile river water, soils, plant materials and meat and liver samples.

Development of a selective and sensitive colour reagent for gold and silver ions and its application to desktop scanner analysis.

Desktop scanners can be favorable alternatives to sophisticated spectrophotometers for the assessment of analytes in complex real samples. Distinctively, our method has been thoroughly investigated, optimized, validated and successfully applied to the assessment of silver and gold in complex real samples, applying syringal rhodanine (SR) as a novel specifically tailored chromogenic reagent and using a desktop scanner as a versatile sensor. Maximum colour absorbance was obtained in the presence of cetylpyridinium chloride (CPC) and cetyltrimethylammonium chloride (CTAC) for silver and gold chelates, respectively. For each metal ion, two ternary complexes were formed depending on the SR concentration with stoichiometries of 1 : 1 : 1 and 1 : 2 : 3 (Ag-SR-CPC) and 1 : 2 : 3 and 1 : 3 : 4 (Au-SR-CTAC), respectively. The methods adhered to Beer's law for 0.15-2.5 and 0.15-2.25 µg mL-1 with detection limits of 0.0089 and 0.0163 µg mL-1 for silver and gold, respectively. The molar absorptivities were 3.63 × 104 and 6.15 × 104 L mol-1 cm-1 at 550 nm and 554 nm, with Sandell's sensitivity indexes of 0.0029 and 0.0032 µg cm-2, respectively. The method was successfully applied to the assessment of silver and gold in a wide range of complex environmental samples.

Modification of AOAC method 973.31 for determination of nitrite in cured meats.

A modification of AOAC Method 973.31 is proposed to improve the extraction efficiency of nitrite from cured meat samples and its subsequent quantification based on the diazotization-coupling reaction of sulfanilamide with N-(1-naphthyl)ethylenediamine dihydrochloride (NED). The various experimental parameters were thoroughly investigated. A 5 g meat sample was mixed with 400 mL water; the pH of the mixture was adjusted to 5.5 +/- 0.3 and allowed to stand for 2 h on a water bath at 80 degrees C, with occasional shaking for the complete extraction of nitrite. After quantitative filtration, an aliquot was mixed with chloroacetic-chloroacetate buffer, pH 1.80 +/- 0.05, sulfanilamide, and NED, and the absorbance of the resulting azodye was recorded at 540 nm against water as a reference. Following the recommended procedure, a linear calibration graph was obtained for up to 0.8 microg/mL NO2(-), with a correlation coefficient of 0.9996 and a detection limit (based on the 3 Sb-criterion) of 5.6 ng/mL NO2(-). The proposed method was conveniently applied to various cured meat samples and was validated by comparison with the original AOAC method and by recovery experiments that gave quantitative results (94-98%) with convenient reproducibility. Statistical analysis of the analytical data could not detect any systematic error and revealed the high accuracy and precision of the proposed method.

The Yxy colour space parameters as novel signalling tools for digital imaging sensors in the analytical laboratory.

Digital imaging devices can be promising, sensitive, and cost-effective chemical sensors for resource-limited settings. Three model colour reactions of iron were used and monitored using a simple platform consisting only of a camera, a cuvette, and a white paper diffuser. A desktop scanner and a mobile phone camera were also used as imaging devices. Captured images were analysed to obtain the RGB intensities (red, green, blue) and were further converted into the corresponding signals of the grayscale, CMY (cyan, magenta, yellow), XYZ (Y: luminance, XZ: chromaticity plane values) and Yxy colour spaces (Y: luminance, xy: chrominance values) analytical signals. The elegant procedure utilizing the Yxy signals surpassed those based on RGB, grayscale, CMY and tristimulus XYZ data regarding the calibration graph linearity and detection limit and compare well with those data obtained from a sophisticated spectrophotometer for assessing iron in complex environmental samples. The simplicity, sensitivity and cost effectiveness of the approach make it suitable for poorly equipped laboratories and locally deprived communities.

Molecular imprinted chitosan-TiO2 nanocomposite for the selective removal of Rose Bengal from wastewater.

A new molecularly imprinted polymer (MIP) chitosan-TiO2 nanocomposite (CTNC) was prepared for the selective and quantitative removal of Rose Bengal dye from industrial wastewater. The physicochemical features of the prepared CTNC-MIP nanoparticles were thoroughly investigated. The prepared MIP nanoparticles exhibited high surface area (95.38m2/g) with relatively uniform mesoporous channels that allowed an exceptional uptake of the dye (qm=79.365mg/g) and reflected the high selectivity of the prepared MIP compared to pure chitosan. The dye uptake was investigated using Freundlich, Langmuir, Dubinin Radushkevich and Temkin models. The kinetics of removal was explored by pseudo-first, pseudo second order, Elovich and Weber-Morris models. The Experimental data fitted well into pseudo-second order model, and much well with the Langmuir isotherm confirming the formation of monolayer of dye molecules. The enthalpy of adsorption was (62.279kJmol-1) showing strong interaction of MIP with the dye. The prepared MIP exhibited a good recyclability and stability.

Difficult Laparoscopic Cholecystectomy and Trainees: Predictors and Results in an Academic Teaching Hospital.

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.