Weight Loss Studies Research Articles

Pattern-based clustering of daily weigh-in trajectories using dynamic time warping.

"Smart"-scales are a new tool for frequent monitoring of weight change as well as weigh-in behavior. These scales give researchers the opportunity to discover patterns in the frequency that individuals weigh themselves over time, and how these patterns are associated with overall weight loss. Our motivating data come from an 18-month behavioral weight loss study of 55 adults classified as overweight or obese who were instructed to weigh themselves daily. Adherence to daily weigh-in routines produces a binary times series for each subject, indicating whether a participant weighed in on a given day. To characterize weigh-in by time-invariant patterns rather than overall adherence, we propose using hierarchical clustering with dynamic time warping (DTW). We perform an extensive simulation study to evaluate the performance of DTW compared to Euclidean and Jaccard distances to recover underlying patterns in adherence time series. In addition, we compare cluster performance using cluster validation indices (CVIs) under the single, average, complete, and Ward linkages and evaluate how internal and external CVIs compare for clustering binary time series. We apply conclusions from the simulation to cluster our real data and summarize observed weigh-in patterns. Our analysis finds that the adherence trajectory pattern is significantly associated with weightloss.

107 Restricted Feeding and Weight Loss Positively Change Fecal Microbiota Populations of Obese Dogs

Abstract Canine obesity negatively influences health and well-being and appears to negatively modify gastrointestinal microbiota populations. Restricted feeding of a specially formulated diet and consequent weight loss may be used to improve health and modify gastrointestinal microbiota. In this study, we aimed to determine the effects of restricted feeding and weight loss on fecal microbiota populations of obese dogs. All procedures were approved by the University of Illinois IACUC prior to experimentation. Twenty-four obese spayed female dogs (BW = 15.2±1.7 kg; BCS = 8.7±0.4; age = 7.2±1.6 y) were used in a 24-wk weight loss study. A control (OR) food was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (wk 0), dogs were allotted to one of two diets: OR or a test (FT) diet and then fed to lose 1.5% BW/wk. Fecal samples were collected at wk 0, 4, 8, 12, 16, 20, and 24 for microbiota and metabolite analyses. Fecal microbiota data were evaluated using QIIME2 and Mixed Models procedure of SAS, with P< 0.05 considered significant. Alpha-diversity was affected by diet and weight loss, with dogs fed OR having a greater alpha-diversity than those fed FT. Weight loss increased alpha-diversity (wk 16, 20, and 24 > wk 0 and 4). Beta-diversity, as assessed by weighted and unweighted PCoA plots, showed separation between dietary groups and between wk 0 and all the other time points after wk 8. Weight loss increased fecal Allobaculum and Ruminococcus torques. Weight loss also increased fecal Bifidobacterium, Faecalibaculum, Parasutterella in dogs fed both diets, but greater in dogs fed OR. Weight loss decreased fecal Collinsella, Turicibacter, Blautia, Ruminococcus gnavus, Faecalibacterium, Peptoclostridium in dogs fed both diets, but greater in dogs fed OR. Our data demonstrate that restricted feeding and weight loss alter fecal microbiota of obese dogs.

Quality of Life after Bariatric Surgery-A Systematic Review.

Background: Most studies analyzing the health-related quality of life (HRQOL) after bariatric treatment ceased at five years post-surgery or even earlier, and it is unclear whether the HRQOL benefit persists for a longer time. This paper reviews sparse evidence regarding HRQOL in patients who underwent bariatric surgery at least nine years prior. Materials and Methods: A of PubMed, Scopus and Google Scholar between 2007–2021 was carried out for the studies investigating HRQOL as an outcome measure in patients after bariatric surgery of any type and having at least a 9-year follow-up. Inconsistent reporting of weight loss or postgraduate study results unrelated to QoL were not included in the study. The study used the PICO procedure. Results: The review of 18 identified publications demonstrated that bariatric treatment seems to provide a persistent benefit in terms of HRQOL, especially its physical component score. Due to psychological predispositions, some patients appear to be less likely to benefit from bariatric treatment, whether in terms of HRQOL or bodyweight reduction. Inconsistent and imprecise studies may limit the evidence included in a review. Conclusions: The early identification of such patients and providing them with holistic care, including psychological intervention, would likely further improve the outcomes of bariatric treatment.

Corrosion inhibition and ecotoxicological assessment of 1,2,3-triazolic alcohols

Here, it is reported the synthesis of two triazole derivatives (1-phenyl-1H-1,2,3-triazole-4-yl)methanol (3a) and (1-(4-nitrophenyl)-1H-1,2,3-triazole-4-yl)methanol (3b)) and their anticorrosive investigation in 1020 mild steel in hydrochloric acid. The corrosion inhibition was evaluated via Weight Loss Study, Linear Polarization Resistance and Electrochemical Impedance Spectroscopy at different temperatures. Maximum efficiencies of 85.1 (3b) and 93.1% (3a) were achieved. Atomic Force Microscopy indicates the formation of a protective layer and physical-chemical parameters indicate that is a chemisorption process for both molecules. Potentiodynamic Polarization curves show that the two triazolic alcohols act as mixed-type corrosion inhibitors. Molecular modeling suggests the electron withdraw effect of nitro group is a crucial factor for the lower efficiency of 3b compared to 3a. Additionally, in silico ecotoxicity prediction suggest the 3a and 3b are less toxic than commercials benzotriazole (BT) and 5-methyl-benzotriazole (5-MeBT).

Neighborhood Walkability Is Associated with Physical Activity and Prediabetes in a Behavioral Weight Loss Study: a Secondary Analysis.

Socio-environmental factors may affect uptake and utility of behavioral interventions targeting weight loss and cardiometabolic health. To evaluate the relation of neighborhood walkability to physical activity (PA) and glucose control in a sample of adults with overweight/obesity participating in a weight loss study. Secondary analysis of a 12-month behavioral weight loss intervention (2011-2015) using one-group pretest-posttest design. Neighborhood walkability was assessed via residential Walk Score (0-100) at study entry. Fasting plasma glucose (FPG) via phlebotomy and PA via waist-worn ActiGraph GT3X were assessed at baseline and end of study. Study variables included neighborhood walkability (car-dependent: Walk Score < 50 vs. walkable: Walk Score ≥ 50), prediabetes (FPG 100-125mg/dL), and recommended PA (moderate to vigorous PA [MVPA] > 22min/day). Generalized linear model with logit link results were reported as adjusted odds ratios (AOR) with 95% confidence intervals (CI). The sample (N = 114) was mostly female (88.6%), white (83.3%), college educated (73.7%), and on average 51.4 ± 1.0years of age. At baseline, persons residing in car-dependent neighborhoods tended to have higher income than those in walkable neighborhoods. Neighborhood walkability interacted with household income at study entry to predict participants' ability to meet the MVPA goal at 12months (AOR = 13.52, 95% CI: 1.86-119.20). Those from walkable neighborhoods had 67% lower odds of having prediabetes compared to those from car-dependent neighborhoods (AOR = 0.33, 95% CI: 0.10-0.87) at 12months. Our findings corroborate previous research characterizing the relationship between neighborhood walkability, PA, and prediabetes status. Key drivers of this impact warrant further investigation in a study with a larger, more diverse sample.

Synthesis, characterisation and corrosion inhibition screening on 2-chloroacetophenone 4-ethyl-3-thiosemicarbazone: morphology, weight loss and DFT studies

Synthesis, characterisation and corrosion inhibition screening on 2-chloroacetophenone 4-ethyl-3-thiosemicarbazone: morphology, weight loss and DFT studies

Effect of alumina insertion on structural properties, thermal stability, and chemical durability of potassium calcium based-phosphate glasses

The synthesis of six aluminum potassium calcium based-phosphate glasses with molar composition of xAl2O3-(50-x)P2O5-10CaO-40K2O, where × = 2.5, 5, 7.5, 10, 12.5, and 15 mol% was complemented. Their structural analyses were performed through XRD, SEM-EDX, DSC, FTIR, and Raman. Further density (ρ) estimations of all samples by the Archimedes method were carried out, and their chemical properties were examined in deionized water, HCl, and NaOH solutions at room temperature. The addition of Al2O3 to the system helped rising the density values (ρ), the glass transition temperature (Tg), and the crystallization temperature (Tx) while reducing the molar volume (Vm). The FTIR and Raman outcomes showed that the addition of alumina into the glass system affects the P - O - P bonds generating novel P-O-Al bonds, which compacts the glassy structure. The glasses’ weight loss studies displayed a decreasing tendency while increasing the content of Al2O3, leading to an enhancement in terms of chemical properties.

Comparison of weight loss data collected by research technicians versus electronic medical records: the PROPEL trial.

Pragmatic trials are increasingly used to study the implementation of weight loss interventions in real-world settings. This study compared researcher-measured body weights versus electronic medical record (EMR)-derived body weights from a pragmatic trial conducted in an underserved patient population. The PROPEL trial randomly allocated 18 clinics to usual care (UC) or to an intensive lifestyle intervention (ILI) designed to promote weight loss. Weight was measured by trained technicians at baseline and at 6, 12, 18, and 24 months. A total of 11 clinics (6 UC/5 ILI) with 577 enrolled patients also provided EMR data (n = 561), which included available body weights over the period of the trial. The total number of assessments were 2638 and 2048 for the researcher-measured and EMR-derived body weight values, respectively. The correlation between researcher-measured and EMR-derived body weights was 0.988 (n = 1 939; p < 0.0001). The mean difference between the EMR and researcher weights (EMR-researcher) was 0.63 (2.65 SD) kg, and a Bland-Altman graph showed good agreement between the two data collection methods; the upper and lower boundaries of the 95% limits of agreement are -4.65 kg and +5.91 kg, and 71 (3.7%) of the values were outside the limits of agreement. However, at 6 months, percent weight loss in the ILI compared to the UC group was 7.3% using researcher-measured data versus 5.5% using EMR-derived data. At 24 months, the weight loss maintenance was 4.6% using the technician-measured data versus 3.5% using EMR-derived data. At the group level, body weight data derived from researcher assessments and an EMR showed good agreement; however, the weight loss difference between ILI and UC was blunted when using EMR data. This suggests that weight loss studies that rely on EMR data may require larger sample sizes to detect significant effects. ClinicalTrials.gov number NCT02561221.

KetoCycle mobile app for ketogenic diet: a retrospective study of weight loss and engagement

BackgroundThe ketogenic diet is one of the oldest diets that has been used for more than a centennial in the clinical setting, and it is gaining popularity as a measure to fight obesity, which is a major predisposing factor for many diseases to manifest, including diabetes mellitus, chronic heart disease, cancer, and others. Thus, we designed this retrospective investigation to determine if users of the mobile application KetoCycle achieved statistically significant weight loss outcomes.MethodsThe initial study cohort comprised 12,965 consecutive users who started using KetoCycle between January 2020 and December 2020. The final cohort comprised 10,269 users. The main parameters obtained from the database containing all self-reported data were gender, number of active days (AD), total time of use (TT), height, initial weight, and last recorded weight. The primary outcome of the study was weight loss. Statistical analyses were performed using IBM SPSS Statistics, version 26 (IBM Corp., Armonk, NY, USA). In addition, a standard multiple regression model was created to predict weight loss from significant actions.ResultsA retrospective analysis of KetoCycle user data showed that 87.3% of KetoCycle users lost some of their initial weight. Of those, 1645 users (18.3%) lost more than 10% of their initial body weight, 3528 (39.3%) users lost between 5 and 10% of their initial body weight, and 3796 (42.3%) users lost less than 5% of their body weight. When user activity was taken into account, it was found that active users lost statistically significantly more weight than non-active users (p < 0.05). App engagement was also associated with losing > 5% of initial weight. Using water tracking, weight tracking, and creation of a meals list within KetoCycle statistically significantly predicted weight loss in a multiple regression model.ConclusionsWe concluded that KetoCycle appeared as a promising mobile application suited for weight loss and weight control.Trial registrationThis retrospective chart review study was approved by BRANY IRB in January 2022 (registration ID.: 21-08-564-939).

The Impact of Pancreatic Enzyme Replacement Therapy on Patients With Advanced Pancreatic Adenocarcinoma: A Systematic Review and Narrative Synthesis.

Advanced pancreatic cancer has a poor prognosis globally. Patients often develop pancreatic exocrine insufficiency leading to malabsorption. This systematic literature review explores the impact of pancreatic enzyme replacement therapy (PERT) on patients with advanced pancreatic cancer. Data sources include MEDLINE, CINAHL, Embase, Cochrane (CENTRAL), PsychINFO, and Joanna Briggs Institute databases from inception to January 14, 2022, with reference list checking on Google Scholar. Narrative synthesis was used as the eligible studies were likely to be heterogeneous and hard to compare. This synthesis approach uses 4 steps: theory development, preliminary synthesis, exploration of relationships, and assessment of the robustness of the synthesis. Four themes arose from analyzing the study outcomes including PERT education, efficacy of PERT, the patient experience, and lack of awareness regarding enzyme replacement. The included studies did not use validated tools or standardized measurements, which made it difficult to compare or draw conclusions. Pancreatic enzyme replacement therapy shows the potential to improve symptoms, nutrition, weight loss, and survival, but high-quality studies with standardized outcomes have not been completed. Patient and health professional education is required because there seems to be a general lack of awareness about the use of PERT in pancreatic cancer.Systematic Review Registration: PROSPERO 2020 CRD42020195986.

Treatment of Acquired Hypothalamic Obesity: Now and the Future.

The hypothalamus is the centre of neuroendocrine regulation of energy homeostasis and appetite. Maldevelopment of, or damage to, the key hypothalamic nuclei disrupts the coordinated balance between energy intake and expenditure leading, to rapid and excessive weight gain. Hypothalamic obesity is compounded by a disruption of the hypothalamic-pituitary axis, sleep disruption, visual compromise, and neurological and vascular sequalae. Amongst suprasellar tumors, craniopharyngioma is the most common cause of acquired hypothalamic obesity, either directly or following surgical or radiotherapeutic intervention. At present, therapy is limited to strategies to manage obesity but with a modest and variable impact. Current approaches include optimizing pituitary hormone replacement, calorie restriction, increased energy expenditure through physical activity, behavioral interventions, pharmacotherapy and bariatric surgery. Current pharmacotherapeutic approaches include stimulants that increase energy consumption, anti-diabetic agents, hypothalamic–pituitary substitution therapy, octreotide, and methionine aminopeptidase 2 (MetAP2) inhibitors. Some pharmacological studies of hypothalamic obesity report weight loss or stabilization but reported intervention periods are short, and others report no effect. The impact of bariatric surgery on weight loss in hypothalamic obesity again is variable. Novel or combined approaches to manage hypothalamic obesity are thus required to achieve credible and sustained weight loss. Identifying etiological factors contributing hypothalamic obesity may lead to multi-faceted interventions targeting hyperphagia, insulin resistance, decreased energy expenditure, sleep disturbance, hypopituitarism and psychosocial morbidity. Placebo-controlled trials using current single, or combination therapies are required to determine the impact of therapeutic agents. A well-defined approach to defining the location of hypothalamic damage may support the use of future targeted therapies. Intranasal oxytocin is currently being investigated as an anorexogenic agent. Novel agents including those targeting pro-opimelanocortin-C and AgRP/NPY expressing neurons and the MC4 receptor may result in better outcomes. This article discusses the current challenges in the management of hypothalamic obesity in children and young people and future therapeutic approaches to increasing weight loss and quality of life in these patients.

Validation of Resting Energy Expenditure Equations in Older Adults with Obesity

It is unclear which energy expenditure prediction equation should guide weight loss interventions in older adults with obesity. We ascertained the validity of four equations commonly used in practice in a series of weight loss studies of adults aged ≥65 with a body mass index ≥30kg/m2 using indirect calorimetry data. Diagnostic accuracy was defined as <10% discrepancy between predicted and measured resting metabolic rate (RMR). Mean was 73.4 years. RMR using the ReeVue was 1,643 kCal. With 59.0% accuracy, the WHO equation demonstrated the highest accuracy while the Harris-Benedict yielded 53.5% accuracy. The Owens equation demonstrated the least variability (21.5% overprediction, 27.8% underprediction) with 50.7% accuracy. A SECA bioimpedance analyzer noted the second lowest accuracy of 49.6%. Only 43.1% of measurements were within 10% of the gold-standard indirect calorimetry value using the Mifflin equation. All equations demonstrated <60% accuracy suggesting a great need for estimating energy needs.

Understanding engagement with Brown Buttabean Motivation, an Auckland grassroots, Pacific-led holistic health programme: a qualitative study

ObjectivesThe aim was to understand how participants engage with Brown Buttabean Motivation (BBM) a grassroots, Pacific-led holistic health programme and the meaning it has in their lives. The objectives were...

English

In this study, chitosan-coatings were prepared with acetic, lactic, propionic, gallic and caffeic acids and used for coating chicken and quail eggs to understand their effect on the quality and shelf-life of chicken and quail eggs. Shelf-life study of (weight loss, Haugh unit, yolk index, albumen pH, mineral levels and shell breaking strength) the coating formulations were investigated for 4 weeks. All chitosan coated chicken and quail egg samples showed greater interior (weight loss, Haugh unit, yolk index, albumen pH) and exterior quality (shell breaking strength) than non-coated samples (p&lt;0.05). &nbsp; Key words: Chitosan, phenolic substances, chicken egg, quail egg, shelf-life.

YIA22-007: Adaptive Nutrition and Exercise Weight loss (A-NEW) Study for Breast Cancer Survivors With Overweight or Obesity

YIA22-007: Adaptive Nutrition and Exercise Weight loss (A-NEW) Study for Breast Cancer Survivors With Overweight or Obesity

Nanofibrous electroconductive nerve guide conduits based on polyaniline‐co‐polydopamine random copolymer for peripheral nerve regeneration

AbstractThe main aim of the current study was to fabricate bio‐ and electro‐active electrospun nanofibrous neural conduits for peripheral nerve regeneration. At first, polyaniline‐co‐polydopamine (PANI‐co‐PDA) random copolymer was synthesized using a chemical oxidation polymerization method. The synthesized copolymer was blended with poly(vinyl alcohol) (PVA) and used for the electrospinning to afford nanofibrous neural conduits. The characterization showed that the fabricated nanofibers have a diameter in the range of 500–600 nm, and the incorporation of PANI‐co‐PDA slightly reduced the hydrophilicity, water absorption capacity, while the electrical conductivity and mechanical properties were increased. The in vitro studies revealed the biodegradability (evaluated using weight loss and morphology study), hemocompatibility (assessed using hemolysis measurement), and biocompatibility (investigated using MTT assay kit) of the fabricated nanofibers. Moreover, the assembled homemade conduit fabricating electrospinning setup resulted in a conduit with proper dimensions, 2 mm in diameter and 2 cm in length. It was found that the fabricated nanofibrous conduits confer proper biological, mechanical, and electrical properties and can be applied as the peripheral nerve regenerating construct.

Schiff Bases Derived from Triazoles as Corrosion Inhibitors for Maraging Steel in Acid Mixtures: Experimental and Theoretical Studies

The ability of two triazole derived Schiff bases, namely,4-[(furan-2-ylmethylidene)amino]-5-methyl-4H-1,2,4-triazole-3-thiol [FAMTT] and 4-[(4-chlorobenzylidene)amino]-5-methyl-4H-1,2,4-triazole-3-thiol [CAMTT], to inhibit corrosion of maraging steel by 2:1 mixture of HCl and H2SO4 was evaluated. Temperature range of 30-45 °C and inhibitor concentration range of 5-25 ppm for FAMTT and 5-50 ppm for CAMTT were employed. An increase in inhibitor concentration and temperature resulted in an increase of inhibition efficiencies of both inhibitors. The inhibition efficiencies of FAMTT were significantly larger than CAMTT in weight loss studies, a maximum of 94.4% observed at 25 ppm for FAMTT and a maximum of 82.4% at 50 ppm observed for CAMTT. However, in the electrochemical studies, though FAMTT performed better than CAMTT, the differences in their efficiencies were somewhat less than that observed in weight loss method. In polarization studies, FAMTT showed maximum efficiency of 96.2% at 25 ppm and 45 °C, while, CAMTT showed a maximum of 90.8% at 50 ppm and 45 °C, and, in electrochemical impedance studies (EIS), maximum efficiency was 97.4% at 25 ppm and 45 °C for FAMTT, and 96.5% at 50 ppm and 45 °C for CAMTT. Inhibition properties of both were verified by kinetic and thermodynamic analyses. Both exhibited mixed type inhibitory action by chemisorbing on the metal surface and followed Langmuir adsorption isotherm. The adsorption of the inhibitors on the steel surface was confirmed by Scanning Electron Microscopy-Energy-dispersive X-ray studies (SEM-EDS) analyses. Density Functional Theory (DFT) calculations were made to predict the inhibition property, and to correlate molecular structure with the corrosion inhibition property. There was a good agreement between experimental observation and theoretical prediction- that FAMTT has higher inhibition potential than CAMTT.

Use of an mHealth Ketogenic Diet App Intervention and User Behaviors Associated With Weight Loss in Adults With Overweight or Obesity: Secondary Analysis of a Randomized Clinical Trial.

BackgroundLow-carbohydrate ketogenic diets are a viable method to lose weight that have regained popularity in recent years. Technology in the form of mobile health (mHealth) apps allows for scalable and remote delivery of such dietary interventions and are increasingly being used by the general population without direct medical supervision. However, it is currently unknown which factors related to app use and user behavior are associated with successful weight loss.ObjectiveFirst, to describe and characterize user behavior, we aim to examine characteristics and user behaviors over time of participants who were enrolled in a remotely delivered clinical weight loss trial that tested an mHealth ketogenic diet app paired with a breath acetone biofeedback device. Second, to identify variables of importance to weight loss at 12 weeks that may offer insight for future development of dietary mHealth interventions, we aim to explore which app- and adherence-related user behaviors characterized successful weight loss.MethodsWe analyzed app use and self-reported questionnaire data from 75 adults with overweight or obesity who participated in the intervention arm of a previous weight loss study. We examined data patterns over time through linear mixed models and performed correlation, linear regression, and causal mediation analyses to characterize diet-, weight-, and app-related user behavior associated with weight loss.ResultsIn the context of a low-carbohydrate ketogenic diet intervention delivered remotely through an mHealth app paired with a breath acetone biofeedback device, self-reported dietary adherence seemed to be the most important factor to predict weight loss (β=–.31; t54=–2.366; P=.02). Furthermore, self-reported adherence mediated the relationship between greater app engagement (from c=–0.008, 95% CI –0.014 to –0.0019 to c’=–0.0035, 95% CI –0.0094 to 0.0024) or higher breath acetone levels (from c=–1.34, 95% CI –2.28 to –0.40 to c’=–0.40, 95% CI –1.42 to 0.62) and greater weight loss, explaining a total of 27.8% and 28.8% of the variance in weight loss, respectively. User behavior (compliance with weight measurements and app engagement) and adherence-related aspects (breath acetone values and self-reported dietary adherence) over time differed between individuals who achieved a clinically significant weight loss of >5% and those who did not.ConclusionsOur in-depth examination of app- and adherence-related user behaviors offers insight into factors associated with successful weight loss in the context of mHealth interventions. In particular, our finding that self-reported dietary adherence was the most important metric predicting weight loss may aid in the development of future mHealth dietary interventions.Trial RegistrationClinicalTrials.gov NCT04165707; https://clinicaltrials.gov/ct2/show/NCT04165707International Registered Report Identifier (IRRID)RR2-10.2196/19053

Effect of weight loss on recurrence of atrial fibrillation after ablative therapy: a systematic review and meta-analysis.

Landmark trials have shown superiority of ablative therapy over medical therapy in certain subpopulation with atrial fibrillation (AF). Previous studies have demonstrated an association between weight loss and reduced rates of recurrence of AF after ablation. The objective of this study is to determine if weight loss reduces the recurrence of AF after ablation. An extensive literature search and systematic review of studies of weight loss on recurrence of AF after ablative therapy was performed. Risk ratio (RR) and 95% confidence intervals were measured for weight loss group versus control group in each study, and comparative analysis as well as subgroup analysis was made. Eight studies with a total of 1,425 patients were included. Overall, studies of patients who lost weight demonstrated lower recurrence of AF (RR 0.35; 95% CI 0.18-0.67). However, subgroup analysis of studies which included patients who lost ≥10% weight loss from baseline showed lower recurrence of AF (RR 0.18; 95% 0.03-0.89), whereas studies which included patients with <10% weight loss did not (RR 1.00; 95% 0.51-1.96). Studies of patients who had less than 12-month history of AF (RR 0.24; 95% CI 0.11-0.57) and those who lost weight prior to ablation (RR 0.40; 95% CI 0.20-0.79) also had lower recurrence of AF. Weight loss is associated with lower long-term recurrence of AF after ablative therapy. Studies of patients with ≥10% weight loss, less than 12-month history of AF, and weight loss prior to ablation experience lower recurrence of AF.

Corrosion Inhibition and Adsorption Mechanism of PVP for Mild Steel in 1.0 M H2SO4: Experimental and Theoretical Approach

Aim:Corrosion of mild steel pipe line when exposed to dilute sulphuric acid is a very serious problem for people in the industry and they are in constant search of highly efficient corrosion inhibitors for acidic medium. For designing new corrosion inhibitors, a through knowledge of corrosion and adsorption mechanism is required.Background:Pitting, cracking and uniform types of corrosion are very common forms of corrosion in dilute sulphuric acid medium. A highly efficient acid corrosion inhibitor is required to minimize all these three forms of corrosion.Objective:The objective was to provide a solution for pitting, cracking, and uniform types of corrosion and to study corrosion and inhibition mechanisms so that highly efficient corrosion inhibitors can be designed.Methods:Polyvinyl pyrrolidone (PVP) was explored as a corrosion inhibitor for mild steel in 1.0 M H2SO4 by experimental and theoretical techniques. Experimental techniques used were impedance, weight loss, metallurgical microscopy, and polarization. Theoretical techniques used were DFT, MD simulation, Frontier molecular orbital, Langmuir, and Frumkin adsorption. Theoretical parameters like interaction energy, adsorption energy, Fukui function, chemical potential, electron density distribution, HOMO/LUMO eigenvalue, etc., help in understanding the mechanism of adsorption of PVP on the Fe (110) surface.Results:Experimental results were supported by theoretical studies. A linear relation was observed between PVP concentration and inhibition efficiency. A maximum of 85.92% inhibition efficiency was observed with a regression coefficient of 0.998. The pore length, the number of pits, and cracks intensity decrease with the concentration of PVP. The waste dilute H2SO4 after the weight loss study was investigated for its biocompatibility and was found to be within the acceptable limit.Conclusion:PVP was proved to be a highly efficient acid corrosion inhibitor for mild steel in 1.0 M H2SO4 medium.