Development of Environment-Friendly Concrete through Partial Addition of Waste Glass Powder (WGP) as Cement Replacement

This paper presents the study carried out on the utilization of Waste Glass Powder (WGP) as supplementary cementitious material in concrete. The evaluation of the influence of WGP on the mechanical properties of concrete was carried out by casting and testing of concrete samples as per ASTM standards (cylinders and beam elements). The control samples were designed to represent field conditions with a target compressive strength of 20,000 kPa. The Portland cement in concrete was substituted with WGP in proportions of 0%-35% by weight, in increments of 5%. Two curing domains were adopted in the preparation of the test samples to evaluate the effect of pozzolanic material wherein the tested samples were cured for 28, 56, and 84 days. The study results indicated a reduction in compressive strength of concrete up to 10% with partial replacement of cement with 25% of WGP when standard curing of 28 days was adopted. Furthermore, with the same replacement proportion and prolonged curing for 84 days, the gap in strength reduction was reduced by 5%. However, a significant decrease in workability was noted between the control concrete samples and glass powder infused concrete. Furthermore, the Waste Glass Powder Concrete (WGPC) exhibited an improved flexural strength with the modulus of rupture for WGPC being 2% higher than control concrete at the age of 84 days. Based on the results of this study it was concluded that 25% replacement of cement with WGP provides an optimum replacement ratio. Doi: 10.28991/cej-2020-03091620 Full Text: PD

Phytophthora-citrus interactions and management strategies: a review

Citrus production is declining worldwide due to several biotic and abiotic factors. The diseases caused by Phytophthora spp. present major economic risks since they are soil-borne and spread quickly if environmental conditions are favorable, or irrigation is poorly managed. Phytophthora species are present in all citrus-producing areas around the world causing significant losses in crop yield and affecting tree health. Bark infection, damping-off, root rot, gummosis, brown rot, and cortical root rot are among the typical symptoms caused by Phytophthora spp. The pathogenicity of Phytophthora spp. depends mainly on the specific interactions between the isolates and citrus cultivars. The use of molecular technologies has allowed the study of Phytophthora-citrus interactions, leading to the identification of several classes of effector proteins secreted by Phytophthora spp. that challenge plant homeostasis and contribute in different ways to disease development and the elucidation of defense mechanisms employed by the host plant. Comprehensive management is need of time to conquer Phytophthora spp. for better root health and citrus productivity

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Population‐based cohort study of outcomes following cholecystectomy for benign gallbladder diseases

Background The aim was to describe the management of benign gallbladder disease and identify characteristics associated with all‐cause 30‐day readmissions and complications in a prospective population‐based cohort. Methods Data were collected on consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing all‐cause 30‐day readmissions and complications were analysed by means of multilevel, multivariable logistic regression modelling using a two‐level hierarchical structure with patients (level 1) nested within hospitals (level 2). Results Data were collected on 8909 patients undergoing cholecystectomy from 167 hospitals. Some 1451 cholecystectomies (16·3 per cent) were performed as an emergency, 4165 (46·8 per cent) as elective operations, and 3293 patients (37·0 per cent) had had at least one previous emergency admission, but had surgery on a delayed basis. The readmission and complication rates at 30 days were 7·1 per cent (633 of 8909) and 10·8 per cent (962 of 8909) respectively. Both readmissions and complications were independently associated with increasing ASA fitness grade, duration of surgery, and increasing numbers of emergency admissions with gallbladder disease before cholecystectomy. No identifiable hospital characteristics were linked to readmissions and complications. Conclusion Readmissions and complications following cholecystectomy are common and associated with patient and disease characteristics

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Phantosmia: A neglected symptom after Dacryocystorhinostomy with intubation (A case report)

A 62-year-old female presented with complaints of persistent phantosmia (foul smell) for the last 4 months. She has a past history of right-sided dacryocystorhinostomy (DCR) 18 months back and left-sided DCR 12 months back. In the initial follow-up period, the patient had frequent visits to her otolaryngologist and ophthalmologist. She experienced phantosmia often but was reassured. The patient presented to us and was examined in an operation theater. It was discovered that the foul-smelling foreign body was present in her right nasal cavity above the middle turbinate. It was removed. A retained gauze piece was revealed to be a cause of phantosmia. The purpose of reporting is to create awareness among ophthalmologists and otolaryngologists. Retained gauze piece following DCR surgery presenting as phantosmia is a new symptom after DCR surgery previously not reported in the literature. Repeated complaints of a postoperative patient, should be dealt with vigilantly and timely

Evaluation of Mechanical Properties of Lightweight Concrete with Pumice Aggregate

This paper presents the findings of a study carried out for evaluation of the mechanical behavior of lightweight concrete. Pumice, a rock resulting from cooling of lava, having entrapped air bubbles, has been used as a light- weight coarse aggregate. Evaluation of the mechanical behavior of the Pumice Lightweight Aggregate Concrete (PLWAC) has been carried out in comparison with the conventional concrete while comparing the mechanical properties of the two. Complete replacement of the coarse aggregate by volume had been carried out in the PLWAC. The testing regime consisted of conducting laboratory tests on concrete samples for evaluation of the mechanical properties including compressive strength, tensile stength, workability and dry density. It was concluded from the results that the use of lightweight aggregate resulted in a reduction in workability, as indicated by the slump test. Moreover, the dry density of PLWAC was also reduced by 30% as compared to the conventional concrete. A significant decrease (49%) in the compressive strength of PLWAC as compared to conventional concrete while a minor difference was observed in the tensile strenght of the two (2.9%). Based on the results of this study, it is recommended that PLWAC cannot be used in structures subjected to heavy loading conditions. However, PLWAC has a good potential to be used in low-cost structures with accompanying benefits of weight reduction

Utilization of waste marble powder as partial replacement of cement in engineered cementitious composite

AbstractThe current study focuses on the utilization of Marble Waste Powder (MWP) as a partial substitution of cement along with local sand instead of microsilica sand in Engineered Cementitious Composite (ECC). The aim was to reduce the environmental concerns of ECC by reducing the cement content without adversely affecting the desired properties. Four mixes were evaluated; the control mix which has no MWP and three test mixes having cement replacement with MWP by 10%, 15%, and 20% were used, respectively. The properties of ECC mixes were found in terms of compressive, tensile, and flexural characteristics. The trend of change in the basic properties of ECC with an increased percentage of MWP as partial substitution of cement was found along with the hypothesis test on the experimental data. From this study, it was concluded that the increased percentage of MWP reduces on the compressive strength of ECC. The maximum reduction in compressive strength of ECC was recorded as 49% with 20% replacement of cement with MWP, as compared to the control sample at 91 days of test age. The tensile strain of ECC increases with the increase in MWP content, while the tensile stress increases only with the increase of MWP content up to a specified limit. The ultimate load in the force–deflection curve first increases with the increase in MWP content up to a certain percentage, while upon further increase in MWP content from 15% to 20%, the ultimate load decreases. The study suggests that the properties do not vary significantly for the modified ECC samples containing MWP, especially the 10% and 15% MWP samples, and can be utilized instead of normal ECC, thus mitigating environmental concerns without compromising the ECC’s performance