Surface Hydroxylation-Induced Electrostatic Forces Thicken Water Films on Quartz.

Aqueous films on mineral surfaces control the physical, chemical, and biological transport processes in the atmosphere, soil, and rocks. Despite the importance of thin films for various research and engineering fields, there are still unanswered questions regarding the roles of the different forces affecting the nature of water films. One of these, the focus of this study, is the development of abnormally thick water films on quartz surfaces. In this study, we developed a density-functional-theory-based model to describe the time-dependent evolution of water films and identify the governing forces responsible for thickening films. We simulated the diffusion of water vapor from ambient air toward mineral surfaces and the formation and thickening of water films at various relative humidity values. Our model predicts an abnormal water film thickness on a hydroxylated quartz surface compared to a surface free of hydroxylation, which explains experimental observations. We further used the model to understand the key interaction forces at different stages of water film formation and thickening. Our model suggests that the attractive hydrogen bonding and van der Waals forces initiate a seed layer of water, and the electrostatic forces, generated by the hydroxylated and thus charged surface, lead to the thickening of water films. This generalizable model can provide insights into the peculiarities of water film development on various mineral surfaces.

Machine learning surrogates for surface complexation model of uranium sorption to oxides.

The safety assessments of the geological storage of spent nuclear fuel require understanding the underground radionuclide mobility in case of a leakage from multi-barrier canisters. Uranium, the most common radionuclide in non-reprocessed spent nuclear fuels, is immobile in reduced form (U(IV) and highly mobile in an oxidized state (U(VI)). The latter form is considered one of the most dangerous environmental threats in the safety assessments of spent nuclear fuel repositories. The sorption of uranium to mineral surfaces surrounding the repository limits their mobility. We quantify uranium sorption using surface complexation models (SCMs). Unfortunately, numerical SCM solvers often encounter convergence problems due to the complex nature of convoluted equations and correlations between model parameters. This study explored two machine learning surrogates for the 2-pK Triple Layer Model of uranium retention by oxide surfaces if released as U(IV) in the oxidizing conditions: random forest regressor and deep neural networks. Our surrogate models, particularly DNN, accurately reproduce SCM model predictions at a fraction of the computational cost without any convergence issues. The safety assessment of spent fuel repositories, specifically the migration of leaked radioactive waste, will benefit from having ultrafast AI/ML surrogates for the computationally expensive sorption models that can be easily incorporated into larger-scale contaminant migration models. One such model is presented here.

The analysis of factors increasing the odds for type 2 diabetes mellitus remission following re-do bariatric surgery after laparoscopic sleeve gastrectomy- cohort study.

INTRODUCTION: Metabolic/bariatric surgery is the only proven treatment for type 2 diabetes mellitus (T2D) with curative intent. However, in a number of patients, the surgery is not effective or they may experience a relapse. Those patients can be offered re-do bariatric surgery (RBS). PURPOSE: The study aimed to determine factors increasing the odds for T2D remission one year after RBS following primary laparoscopic sleeve gastrectomy. METHODS: A multicenter retrospective cohort study was conducted between January 2010 and January 2020, which included 12 bariatric centers in Poland. The study population was divided into groups: Group 1- patients with T2D remission after RBS (n = 28) and Group 2- patients without T2D remission after RBS (n = 49). T2D remission was defined as HBA1c < 6.0% without glucose-lowering pharmacotherapy and glycemia within normal range at time of follow-up that was completed 12 months after RBS. RESULTS: Fifty seven females and 20 males were included in the study. Patients who achieved BMI < 33 kg/m2 after RBS and those with %EBMIL > 60.7% had an increased chance of T2D remission (OR = 3.39, 95%CI = 1.28-8.95, p = 0.014 and OR = 12.48, 95%CI 2.67-58.42, p = 0.001, respectively). Time interval between primary LSG and RBS was significantly shorter in Group 1 than in Group 2 [1 (1-4) vs. 3 (2-4) years, p = 0.023]. CONCLUSIONS: Shorter time interval between LSG and RBS may ease remission of T2D in case of lack of remission after primary procedure. Significant excess weight loss seems to be the most crucial factor for T2D remission.

Rapid Prediction of a Liquid Structure from a Single Molecular Configuration Using Deep Learning.

Molecular dynamics simulation is an indispensable tool for understanding the collective behavior of atoms and molecules and the phases they form. Statistical mechanics provides accurate routes for predicting macroscopic properties as time-averages over visited molecular configurations - microstates. However, to obtain convergence, we need a sufficiently long record of visited microstates, which translates to the high-computational cost of the molecular simulations. In this work, we show how to use a point cloud-based deep learning strategy to rapidly predict the structural properties of liquids from a single molecular configuration. We tested our approach using three homogeneous liquids with progressively more complex entities and interactions: Ar, NO, and H2O under varying pressure and temperature conditions within the liquid state domain. Our deep neural network architecture allows rapid insight into the liquid structure, here probed by the radial distribution function, and can be used with molecular/atomistic configurations generated by either simulation, first-principle, or experimental methods.

Distance-dependent dielectric constant at the calcite/electrolyte interface: Implication for surface complexation modeling.

HYPOTHESIS: The electrical double layer formed at the mineral/electrolyte interface is often modeled using mean-field approaches based on a continuum description of the solvent whose dielectric constant is assumed to decrease monotonically with decreasing distance to the surface. In contrast, molecular simulations show that the solvent polarizability oscillates near the surface similar to the water density profile - as shown previously, for example, by Bonthuis et al. (D.J. Bonthuis, S. Gekle, R.R. Netz, Dielectric Profile of Interfacial Water and its Effect on Double-Layer Capacitance, Phys Rev Lett 107(16) (2011) 166102). We showed that molecular and mesoscale pictures agree by spatially averaging the dielectric constant obtained from molecular dynamics simulations over the distances relevant to the mean-field representation. In addition, the values of capacitances used to describe the electrical double layer in Surface Complexation Models (SCMs) of the mineral/electrolyte interface can be estimated using molecularly informed spatially averaged dielectric constants and positions of hydration layers. EXPERIMENTS: First, we used molecular dynamics simulations to model the calcite 101¯4/electrolyte interface. Next, by using atomistic trajectories, we calculated the distance-dependent static dielectric constant and water density in the direction normal to the. Finally, we applied spatial compartmentalization consistent with the model of parallel-plate capacitors connected in series to estimate SCM capacitances. FINDINGS: Computationally expensive simulations are required to determine the dielectric constant profile of interfacial water near the mineral surface. On the other hand, water density profiles are readily assessable from much shorter simulation trajectories. Our simulations confirmed that dielectric and water density oscillations at the interface are correlated. Here, we parametrized linear regression models to estimate the dielectric constant directly from the local water density. This is a significant computational shortcut compared to slowly converging calculations relying on total dipole moment fluctuations. The amplitude of the interfacial dielectric constant oscillation can exceed the dielectric constant of the bulk water, suggesting an ice-like frozen state, but only if there are no electrolyte ions. The interfacial accumulation of electrolyte ions causes a decrease in the dielectric constant due to the reduction of water density and re-orientation of water dipoles in ion hydration shells. Finally, we show how to use the computed dielectric properties to estimate SCM's capacitances.

Differences in Technical Aspects of Primary Sleeve Gastrectomy Prior to Redo Bariatric Surgery-A Multicenter Cohort Study (PROSS Study).

Background and Objectives: Although the technical simplicity of laparoscopic sleeve gastrectomy is relatively well understood, many parts of the procedure differ according to bariatric surgeons. These technical variations may impact postoperative weight loss or the treatment of comorbidities and lead to qualification for redo procedures. Materials and Methods: A multicenter, observational, retrospective study was conducted among patients undergoing revision procedures. Patients were divided into three groups based on the indications for revisional surgery (insufficient weight loss or obesity-related comorbidities treatment, weight regain and development of complications). Results: The median bougie size was 36 (32-40) with significant difference (p = 0.04). In 246 (51.57%) patients, the resection part of sleeve gastrectomy was started 4 cm from the pylorus without significant difference (p = 0.065). The number of stapler cartridges used during the SG procedure was six staplers in group C (p = 0.529). The number of procedures in which the staple line was reinforced was the highest in group A (29.63%) with a significant difference (0.002). Cruroplasty was performed in 13 patients (p = 0.549). Conclusions: There were no differences between indications to redo surgery in terms of primary surgery parameters such as the number of staplers used or the length from the pylorus to begin resection. The bougie size was smaller in the group of patients with weight regain. Patients who had revision for insufficient weight loss were significantly more likely to have had their staple line oversewn. A potential cause could be a difference in the size of the removed portion of the stomach, but it is difficult to draw unequivocal conclusions within the limitations of our study.

Concentration of Polycyclic Aromatic Hydrocarbons (PAHs) in Human Serum and Adipose Tissues and Stimulatory Effect of Naphthalene in Adipogenesis in 3T3-L1 Cells.

Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent classes of environmental pollutants. Some evidence shows that PAHs could be involved in human obesity. However, little is known about the distribution patterns of PAHs in human adipose tissue (AT) and the role of PAHs on adipogenesis/lipogenesis. The aims of this pilot study were to determine concentrations of 16 PAHs defined as high-priority pollutants in the plasma and adipose tissue of French and Polish bariatric patients, as well as their correlation with body mass index (BMI), plasma and AT adipokines expression levels. We finally investigated the role of naphthalene on cell proliferation, viability, and differentiation in 3T3-L1 preadipocytes. The concentration of most PAHs was similar in the three types of AT and it was significantly higher in AT as compared to plasma, suggesting bioaccumulation. Polish patients had higher PAH levels in AT than French ones. Only the concentration of naphthalene in AT was positively correlated with the BMI and serum or adipose chemerin, adiponectin and resistin expression, in French but not in Polish patients, who had significantly higher BMIs. Moreover, naphthalene exposure increased the cell proliferation of 3T3-L1 preadipocytes and lipogenesis, and increased the expression of genes involved in adipogenesis after cell differentiation. Taken together, PAHs and more particularly naphthalene could be an obesogenic molecule and increase the risk of obesity.

Analysis of the risk factors for perioperative morbidity after laparoscopic revisional bariatric procedures: results from the multicenter Polish Revision Obesity Surgery Study.

BACKGROUND: The growing number of primary bariatric operations has led to an increase in demand for revision surgeries. Higher numbers of revisional operations are also observed in Poland, yet their safety and efficacy remain controversial because of a lack of current recommendations and guidelines. OBJECTIVE: To review risk factors influencing perioperative morbidity. METHODS: A retrospective study was conducted to analyze the results of surgical treatment among 12 Polish bariatric centers. Inclusion criteria were laparoscopic revisional bariatric surgeries and patients ≥18 years of age. The study included 795 patients, of whom 621 were female; the mean age was 47 years (range: 40-55 years). RESULTS: Perioperative morbidity occurred in 92 patients (11.6%) enrolled in the study, including 76 women (82.6%). The median age was 45 years (range: 39-54 years). Statistically significant risk factors in univariate logistic regression models for perioperative complications were the duration of obesity, revisional surgery after Roux-en-Y gastric bypass (RYGB) or adjustable gastric band (AGB), difference in body mass index before revisional surgery and the lowest achieved after primary surgery, and postoperative morbidity of the primary surgery as the cause for revisional bariatric surgery. These factors were included in the multivariate regression model. Revisional surgery after AGB (odds ratio [OR] = 2.18; 95% confidence interval [CI]: 1.28-3.69; P = .004), revisional surgery performed after RYGB (OR = 6.52; 95% CI: 1.98-21.49; P = .002), and revisions due to complication of the primary surgery (OR = 1.89; 95% CI: 1.06-3.34; P = .030) remained independent risk factors for perioperative morbidity. CONCLUSION: Revisional operations after RYGB or AGB and those performed because of postoperative morbidity after primary surgery as the main cause for revisional surgery were associated with a significantly increased risk of postoperative morbidity.

Revisional bariatric procedures in the group of patients over 60 years of age: a multicenter cohort study (PROSS Study).

Introduction: The constantly increasing prevalence of obesity in the population and the lengthening of life expectancy affect the appearance of the problem of pathological obesity also in the elderly. At the same time, an increase in the number of bariatric procedures (also revisional) performed in elderly patients is observed. Aim: To assess the indications for revisional bariatric procedures along with the safety and postoperative results in the group of patients over 60 years of age. Material and methods: The study was conducted in 2019-2020 among patients undergoing revisional bariatric procedures in Polish bariatric centers. The data were obtained through a multicenter, observational retrospective study. Results: Our data consist of 55 (8.1%) patients older than 60 years of age who underwent revisional bariatric procedures. Revisional procedures in the group of patients over 60 years of age had fewer postoperative complications (16.4% vs. 23.1%, p < 0.05). Remission of type II diabetes or arterial hypertension was achieved to a lesser extent in patients operated on over the age of 60 (13% and 15%, respectively) compared to patients operated on under the age of 60 (47% and 34%, respectively; p < 0.05). Conclusions: Revisional bariatric procedures in the group of patients over 60 years of age do not cause an increased risk of postoperative complications or prolonged hospital stay. The possibility of achieving remission or improvement in the treatment of comorbidities in patients operated on over 60 years of age is relatively lower compared to a younger group.

A reverse-selective ion exchange membrane for the selective transport of phosphates via an outer-sphere complexation-diffusion pathway.

Specific-ion selectivity is a highly desirable feature for the next generation of membranes. However, existing membranes rely on differences in charge, size and hydration energy, which limits their ability to target individual ion species. Here we demonstrate a nanocomposite ion-exchange membrane material that enables a reverse-selective transport mechanism that can selectively pass a single ion species. We demonstrate this transport mechanism with phosphate ions selectively transporting across negatively charged cation exchange membranes. Selective transport is enabled by the in situ growth of hydrous manganese oxide nanoparticles throughout a cation exchange membrane that provide a diffusion pathway via phosphate-specific, reversible outer-sphere interactions. On incorporating the hydrous manganese oxide nanoparticles, the membrane's phosphate flux increased by a factor of 27 over an unmodified cation exchange membrane, and the selectivity of phosphorous over sulfate, nitrate and chloride reaches 47, 100 and 20, respectively. By pairing ion-specific outer-sphere interactions between the target ions and appropriate nanoparticles, these nanocomposite ion-exchange materials can, in principle, achieve selective transport for a range of ions.

Revisional operations among patients after surgical treatment of obesity: a multicenter Polish Revision Obesity Surgery Study (PROSS).

Introduction: Revisional surgery is more technically challenging and associated with increased morbidity and mortality. Nevertheless, the frequency of revisional bariatric surgery (RBS) is increasing. Therefore, investigating this group of patients appears to be currently valid. Aim: The objective of this multicenter study was to collect, systematize and present the available data on RBS after surgical treatment of morbid obesity among Polish patients. Material and methods: This multicenter study included a retrospective analysis of a prospectively maintained database. Outcomes included an analysis of the indications for RBS, the type of surgery most frequently chosen as RBS and the course of the perioperative period of treatment among patients undergoing RBS. Results: The group consisted of 799 patients (624 (78.1%) women, 175 (21.9%) men). The mean age was 38.96 ±9.72 years. Recurrence of obesity was the most common indication for RBS. The most frequently performed RBS procedures were one anastomosis gastric bypass (OAGB) - 294 (36.8%) patients, Roux-en-Y gastric bypass (RYGB) - 289 (36.17%) patients and sleeve gastrectomy (SG) - 172 (21.52%) patients. After primary surgery 63.58% of patients achieved sufficient weight loss, but after RBS only 38.87%. Complications were noted in 222 (27.78%) cases after RBS with GERD being the most common - 117 (14.64%) patients. Conclusions: RBS most often concerns patients after SG. The main indication for RBS is weight regain. OAGB and RYGB were the two most frequently chosen types of RBS. Secondary operations lead to further weight reduction. However, RBS are associated with a significant risk of complications.

The Effect of the Addition of Low-Alkaloid Lupine Flour on the Glycemic Index In Vivo and the Physicochemical Properties and Cooking Quality of Durum Wheat Pasta.

The aim of this research was to determine the effect of the addition of lupine flour (LF) on the values of the glycemic index (GI) and glycemic load (GL), physicochemical properties, and cooking quality of durum semolina pasta. The pasta was enriched with 0-25% of lupine flour (LF0-LF25). Additionally, 7.5 and 20% of oat ß-glucans, 5% of vital gluten, and 20% of millet flour were used in a selected sample. The addition of 7.5% ß-glucans and 5% vital gluten to the product resulted in only a slight decrease in the GI of the products. A significant decrease in pasta GI was noted after the addition of 20% of lupine flour. The product enriched with 20% of lupine flour, 20% of ß-glucans, and 20% of millet flour had the lowest glycemic index and glycemic load (GI = 33.75%, GL = 7.2%, respectively). At the same time, the lupine-flour-enriched products were characterized by an increased concentration of protein, fat, ash, and dietary fiber. The addition of lupine flour at the level of up to 20% yielded functional products characterized by good cooking quality.

Chemical, technological, and sensory evaluation of the suitability of coconut by-products in white rolls.

BACKGROUND: Fortification of rolls, one of the most popular snacks for children and adults, with coconut by-products can be interesting in terms of both nutritional enrichment and reduction of food waste. Coconut by-products, such as residues from coconut milk (RCM) and coconut oil (RCO) extraction, are a valuable source of dietary fiber. In the study, coconut flours obtained from RCM and RCO were used (FCM and FCO, respectively) for supplementation of rolls; white wheat flour was replaced with FCM or FCO at levels of 6, 12, and 18 g per 100 g. RESULTS: The effect of the addition of the coconut by-products on the nutritional value, sensory evaluation, physical properties, and texture of rolls was determined after 24 and 72 h of storage. The research showed a positive effect of FCM and FCO on the roll yield, crumb moisture, and baking loss. The sensory evaluation revealed that the 12% addition of coconut residues yielded products with high overall acceptability (8 points on a 9-point scale). Compared with the control, a 12% addition of FCO or FCM contributed to an increase in proteins of 7.9% and 3.9% respectively and an increase in dietary fiber of 76% and 57% respectively. Despite the increase in the fat and protein contents, the energy value of the coconut rolls was significantly lower (244.6 kcal and 245.3 kcal for FCO and FCM respectively) than in the control wheat rolls (266.0 kcal). CONCLUSION: White rolls with coconut flours obtained after grinding residues from oil or coconut milk extraction significantly increased the nutritional value of the rolls. © 2021 Society of Chemical Industry.

The prevalence of, and risk factors for, Barrett's oesophagus after sleeve gastrectomy.

INTRODUCTION: Sleeve gastrectomy has become one of the most performed bariatric procedures. There is increasing evidence that sleeve gastrectomy patients suffer from gastroesophageal reflux disease and its sequelae such as erosive oesophagitis (EO) or Barret's oesophagus (BO). AIM: To evaluate the incidence of EO and BO among patients with normal preoperative oesophagogastroduodenoscopy findings, who underwent sleeve gastrectomy, and investigate factors that may contribute to the development of EO and BO after the surgery. MATERIAL AND METHODS: We conducted a single-centre longitudinal study that included patients who underwent sleeve gastrectomy and completed 5 years of follow-up. Gastroscopies were performed in all patients at the end of the follow-up period. Patient- and treatment-related factors were used to search for risk factors of BO. RESULTS: From a total of 30 patients, symptomatic reflux was reported by 17 (56.7%) during the follow-up period. At EGD EO was found in 9 of those patients (30%), whereas BE was diagnosed in 8 (27%) patients. The median BMI at the end of the follow-up period was significantly higher among patients with BE than in the groups with EO and with no endoscopic changes: 40.91 ±6.32, 32.42 ±5.53, and 33.25 ±4.41, respectively (p = 0.04). CONCLUSIONS: The prevalence of BO in SG patients is considerable. The risk of BE increases in patients with poor bariatric outcome. Endoscopic surveillance should be considered as part of the follow-up, especially in patients with higher overall risk of BE.

Stinging Nettle (Urtica dioica L.) as a Functional Component in Durum Wheat Pasta Production: Impact on Chemical Composition, In Vitro Glycemic Index, and Quality Properties.

Stinging nettle (Urtica dioica L.) is a good source of biologically active compounds with proven beneficial health effects. This study aimed to investigate the effect of nettle herb supplementation on chemical composition, including the content of selected minerals and pigments, the in vitro glycemic response, and the cooking and sensory quality of extruded pasta. Tagliatelle-shaped pasta was produced under semi-technical scale by partial replacement of durum wheat semolina with 0, 1, 2, 3, 4, and 5% of lyophilized nettle. The partial substitution with freeze-dried nettle caused a statistically significant (p ≤ 0.05) increase in the content of minerals, especially calcium, iron, potassium, and magnesium in the products. The calcium content in the pasta fortified with 5%-addition of stinging nettle was 175.9 mg 100 g-1 and this concentration was 5.8 times higher than in the control sample. At the same time, high content of chlorophylls and carotenoids (237.58 µg g-1 and 13.35 µg g-1, respectively) was noticed. Enriching pasta with a 0-5% addition of stinging nettle resulted in a statistically significant (p ≤ 0.05) increase in the content of the total dietary fiber (TDF) (from 5.1 g 100 g-1 to 8.82 g 100 g-1) and the insoluble dietary fiber (IDF) (from 2.29 g 100 g-1 to 5.63 g 100 g-1). The lowest hydrolysis index of starch (HI = 17.49%) and the lowest glycemic index (GI = 49.31%) were noted for the pasta enriched with 3% nettle.

Hiatal Hernia Repair during Laparoscopic Sleeve Gastrectomy: Systematic Review and Meta-analysis on Gastroesophageal Reflux Disease symptoms changes.

Introduction Obesity is associated with a higher prevalence of various comorbidities including gastroesophageal reflux disease. It is yet still unclear whether LSG exacerbates or alleviates GERD symptoms. Available date in the literature on LSG influence on GERD are contradictory. Material and methods Systematic review of literature comparing GERD in sleeve gastrectomy versus sleeve gastrectomy with concomtitant hiatal repair. The review was conducted in January 2021 in accordance to PRISMA guidelines. Inclusion criteria involved reporting GERD and comparison of above mentioned techniques. Primary outcome of interest were alleviation of GERD and "de-novo" GERD symptoms. Secondary outcomes were operative time and morbidity. Results Initial search yielded 831 records. After the review and full-text screening 5 studies were included in the analysis. There were no differences in terms of GERD outcomes, p=0.74 for alleviation, p=0.77 for new symptoms. Concomitant hiatal hernia repair significantly prolongs sleeve gastrectomy by 38 mins. Conclusion There are no differences in GERD between hiatal hernia repair during sleeve gastrectomy in comparison to sleeve gastrectomy alone. More high-quality studies are required to fully evaluate this subject.

30-Day Morbidity and Mortality of Bariatric Surgery During the COVID-19 Pandemic: a Multinational Cohort Study of 7704 Patients from 42 Countries.

BACKGROUND: There are data on the safety of cancer surgery and the efficacy of preventive strategies on the prevention of postoperative symptomatic COVID-19 in these patients. But there is little such data for any elective surgery. The main objectives of this study were to examine the safety of bariatric surgery (BS) during the coronavirus disease 2019 (COVID-19) pandemic and to determine the efficacy of perioperative COVID-19 protective strategies on postoperative symptomatic COVID-19 rates. METHODS: We conducted an international cohort study to determine all-cause and COVID-19-specific 30-day morbidity and mortality of BS performed between 01/05/2020 and 31/10/2020. RESULTS: Four hundred ninety-nine surgeons from 185 centres in 42 countries provided data on 7704 patients. Elective primary BS (n = 7084) was associated with a 30-day morbidity of 6.76% (n = 479) and a 30-day mortality of 0.14% (n = 10). Emergency BS, revisional BS, insulin-treated type 2 diabetes, and untreated obstructive sleep apnoea were associated with increased complications on multivariable analysis. Forty-three patients developed symptomatic COVID-19 postoperatively, with a higher risk in non-whites. Preoperative self-isolation, preoperative testing for SARS-CoV-2, and surgery in institutions not concurrently treating COVID-19 patients did not reduce the incidence of postoperative COVID-19. Postoperative symptomatic COVID-19 was more likely if the surgery was performed during a COVID-19 peak in that country. CONCLUSIONS: BS can be performed safely during the COVID-19 pandemic with appropriate perioperative protocols. There was no relationship between preoperative testing for COVID-19 and self-isolation with symptomatic postoperative COVID-19. The risk of postoperative COVID-19 risk was greater in non-whites or if BS was performed during a local peak.

The Steady March toward Biomimetic Nanoelectronics.

Steady progress is being made in unveiling nature's long-range charge transport mechanisms in redox proteins and in the development of versatile self-assembling scaffolds and de novo proteins by design-two separate fields that soon may intersect to yield the first artificial bioelectronic wires. Here, we summarize compelling developments in these areas that put a spotlight on the prospect of their convergence, featuring, in particular, work by Dai et al. in this issue of ACS Nano that illustrates success in intentional design with nuanced control, binding multiple c-type hemes into a specific ordered array bearing the essential hallmarks of heme chains in bacterial multiheme cytochromes.

Unseeded, spontaneous nucleation of spherulitic magnesium calcite.

Most of the sedimentary carbonates deposited in the marine environments are composed of calcium carbonate minerals with varying amounts of incorporated Mg2+. However, understanding how interactions of impurities with carbonate and their incorporation affect sediments behavior remains a challenge. Here, a new insight is obtained by monitoring solution composition, morphology, and electrokinetic potential of carbonate particles formed in a spontaneous unseeded batch precipitation experiment using electrochemical and scanning electron microscopy methods. The solid composition and growth rate are extracted from changes in the bulk composition and fitted to chemical affinity rate law, revealing that the precipitation pathway consists of second-order dissolution and first-order precipitation. The molecular dynamics simulations show that the lattice strain induced by randomly substituting Ca2+ by Mg2+ stabilizes spherical nanoparticles and reduces their surface area and volume. Combining kinetics and thermodynamics insight, we conclude that variation in the carbonate bulk and interfacial energies, along with the solution supersaturation, lead to the dissolution-precipitation transformation pathway from Mg-rich to Mg-poor carbonate phase that preserves spherulitic morphology. Our findings are relevant for long-standing questions of how impurities influence diagenesis of carbonate sediments and spherulitic carbonate particles' origin.

Laparoscopic Sleeve Gastrectomy with Omentopexy: Is It Really a Promising Method?-A Systematic Review with Meta-analysis.

PURPOSE: Laparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed bariatric procedure worldwide. Omentopexy during LSG is a novel variation of this well-established technique. There are no clear conclusions on indications for this procedure, safeness, and effects of such a method. We aimed to compare the outcomes of laparoscopic sleeve gastrectomy (LSG) with omentopexy (OP) and without omentopexy. MATERIALS AND METHODS: We searched the Medline, EMBASE, and Scopus databases up-to June 2020. Full-text articles and conference abstracts were included for further analysis. This review follows the PRISMA guidelines. RESULTS: Of initial 66 records, only 4 studies (N = 1396 patients) were included in the meta-analysis. Our findings showed that LSG with omentopexy had significantly lowered overall morbidity compared to LSG without omentopexy (RR = 0.38; 95% CI [0.15, 0.94]; p=0.04). Gastric leakage rate (RR = 0.17; 95% CI [0.04, 0.76]; p = 0.02) was also significantly lower in LSG with omentopexy. There were no significant differences between groups in length of hospital stay. CONCLUSIONS: Our meta-analysis showed that LSG with omentopexy may be a feasible procedure for decreasing morbidity and gastric leak rate. However, despite promising results, the procedure needs to be researched more in randomized controlled studies to draw solid conclusions.