Tuning the Mechanical Properties of Multiarm RAFT-Based Block Copolyelectrolyte Hydrogels via Ionic Cross-Linking for 3D Cell Cultures.

Hydrogels that serve as native extracellular matrix (ECM) mimics are typically naturally derived hydrogels that are physically cross-linked via ionic interactions. This means rapid gelation of synthetic polymers, which give control over the chemical and physical cues in hydrogel formation. Herein, we combine the best of both systems by developing a synthetic hydrogel with ionic cross-linking of block copolyelectrolytes to rapidly create hydrogels. Reversible addition-fragmentation chain-transfer (RAFT) polymerization was used to synthesize oppositely charged polyelectrolyte molecules and, in turn, modulate the mechanical property of stiffness. The mechanical stiffness of a range of 900-3500 Pa was tuned by varying the number of charged ionic groups, the length of the polymer arms, and the polymer concentration. We demonstrate the synthetic polyelectrolyte hydrogel as an ECM mimic for three-dimensional (3D) in vitro cell models using MCF-7 breast cancer cells.

A systematic review of randomized controlled trials and reviews in the management of ventral hernias.

BACKGROUND: The literature supporting ventral hernia management is growing; however, it is unclear whether the quality of work is improving. We hypothesize that the quality of clinical ventral hernia research has improved over the past 2.5 decades. METHODS: A review of MEDLINE, Scopus, and Cochrane databases was conducted for all ventral hernia studies from January 1, 1980 to May 1, 2015. Relevant abstracts were assigned a level according to the Oxford Center for Evidence-Based Medicine. Reviews, and meta-analyses were graded using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Checklist and randomized controlled trials (RCTs) using the Consolidated Standards of Reporting Trials (CONSORT) checklist. Studies that did not fulfill at least 70% of the elements for the PRISMA (19/27) or CONSORT (26/37) checklists were considered to contain substantial methodological flaws. RESULTS: Of 12,431 citations, 1336 met criteria for quality evaluation. Level 1 studies were sparse (n = 104, 7.8%), and most were level 2 or 3 (n = 463, 34.7%) or 4 (n = 769, 57.6%). Of the level 1 studies, 37 (35.6%) were RCTs, 61(58.7%) were reviews and/or meta-analyses, and 6 (5.8%) were consensus statements. Most RCTs and reviews and/or meta-analyses contained substantial methodological flaws (75.7%, 75.8%). Critical areas of weakness in RCTs were explaining losses and exclusions after randomization and/or allocation and reporting determination of sample size. For reviews and/or meta-analyses, areas of weakness were presenting an electronic search strategy and providing an assessment of risk of bias before pooling data. Linear regressions of PRISMA and CONSORT scores demonstrated improvement over time (PRISMA slope 0.95, R(2) = 0.24; CONSORT slope 0.34, R(2) = 0.08). CONCLUSIONS: Although the quality of literature guiding ventral hernia management has improved over time, there is room for improvement.

Mesh Location in Open Ventral Hernia Repair: A Systematic Review and Network Meta-analysis.

There is no consensus on the ideal location for mesh placement in open ventral hernia repair (OVHR). We aim to identify the mesh location associated with the lowest rate of recurrence following OVHR using a systematic review and meta-analysis. A search was performed for studies comparing at least two of four locations for mesh placement during OVHR (onlay, inlay, sublay, and underlay). Outcomes assessed were hernia recurrence and surgical site infection (SSI). Pairwise meta-analysis was performed to compare all direct treatment of mesh locations. A multiple treatment meta-analysis was performed to compare all mesh locations in the Bayesian framework. Sensitivity analyses were planned for the following: studies with a low risk of bias, incisional hernias, by hernia size, and by mesh type (synthetic or biologic). Twenty-one studies were identified (n = 5,891). Sublay placement of mesh was associated with the lowest risk for recurrence [OR 0.218 (95% CI 0.06-0.47)] and was the best of the four treatment modalities assessed [Prob (best) = 94.2%]. Sublay was also associated with the lowest risk for SSI [OR 0.449 (95% CI 0.12-1.16)] and was the best of the 4 treatment modalities assessed [Prob (best) = 77.3%]. When only assessing studies at low risk of bias, of incisional hernias, and using synthetic mesh, the probability that sublay had the lowest rate of recurrence and SSI was high. Sublay mesh location has lower complication rates than other mesh locations. While additional randomized controlled trials are needed to validate these findings, this network meta-analysis suggests the probability of sublay being the best location for mesh placement is high.

Laparoscopic repair reduces incidence of surgical site infections for all ventral hernias.

BACKGROUND: The role of laparoscopic repair of ventral hernias remains incompletely defined. We hypothesize that laparoscopy, compared to open repair with mesh, decreases surgical site infection (SSI) for all ventral hernia types. METHODS: MEDLINE, EMBASE, and Cochrane databases were reviewed to identify studies evaluating outcomes of laparoscopic versus open repair with mesh of ventral hernias and divided into groups (primary or incisional). Studies with high risk of bias were excluded. Primary outcomes of interest were recurrence and SSI. Fixed effects model was used unless significant heterogeneity, assessed with the Higgins I square (I(2)), was encountered. RESULTS: There were 5 and 15 studies for primary and incisional cohorts. No difference was seen in recurrence between laparoscopic and open repair in the two hernia groups. SSI was more common with open repair in both hernia groups: primary (OR 4.17, 95%CI [2.03-8.55]) and incisional (OR 5.16, 95%CI [2.79-9.57]). CONCLUSIONS: Laparoscopic repair, compared to open repair with mesh, decreases rates of SSI in all types of ventral hernias with no difference in recurrence. These data suggest that laparoscopic approach may be the treatment of choice for all types of ventral hernias.

Primary fascial closure with laparoscopic ventral hernia repair: systematic review.

Laparoscopic ventral hernia repair (LVHR) has grown in popularity. Typically, this procedure is performed with a mesh bridge technique that results in high rates of seroma, eventration (bulging), and patient dissatisfaction. In an effort to avoid these complications, there is growing interest in the role of laparoscopic primary fascial closure with intraperitoneal mesh placement. This systematic review evaluated the outcomes of closure of the central defect during LVHR. A literature search of PubMed, Cochrane databases, and Embase was conducted using PRISMA guidelines. MINORS was used to assess the methodologic quality. Primary outcome was hernia recurrence. Secondary outcomes were surgical-site infection, seroma formation, bulging, and patient-centered items (satisfaction, chronic pain, functional status). Eleven studies were identified, eight of which were case series (level 4 data). Three comparative studies examined the difference between closure and nonclosure of the fascial defect during laparoscopic ventral incisional hernia repairs (level 3 and 4 data). These studies suggested that primary fascial closure (n = 138) compared to nonclosure (n = 255) resulted in lower recurrence rates (0-5.7 vs. 4.8-16.7 %) and seroma formation rates (5.6-11.4 vs. 4.3-27.8 %). Follow-up periods for both groups were similar (1-108 months). Only one study evaluated patient function and clinical bulging. It showed better outcomes with primary fascial closure. Closure of the central defect during LVHR resulted in less recurrence, bulging, and seroma than nonclosure. Patients with closure were more satisfied with the results and had better functional status. The quality of the data was poor, however. A randomized controlled trial to evaluate the role of closure of the central defect during LVHR is warranted.

Carbon Nanodot-Microbe-Plant Nexus in Agroecosystem and Antimicrobial Applications.

The intensive applications of nanomaterials in the agroecosystem led to the creation of several environmental problems. More efforts are needed to discover new insights in the nanomaterial-microbe-plant nexus. This relationship has several dimensions, which may include the transport of nanomaterials to different plant organs, the nanotoxicity to soil microbes and plants, and different possible regulations. This review focuses on the challenges and prospects of the nanomaterial-microbe-plant nexus under agroecosystem conditions. The previous nano-forms were selected in this study because of the rare, published articles on such nanomaterials. Under the study's nexus, more insights on the carbon nanodot-microbe-plant nexus were discussed along with the role of the new frontier in nano-tellurium-microbe nexus. Transport of nanomaterials to different plant organs under possible applications, and translocation of these nanoparticles besides their expected nanotoxicity to soil microbes will be also reported in the current study. Nanotoxicity to soil microbes and plants was investigated by taking account of morpho-physiological, molecular, and biochemical concerns. This study highlights the regulations of nanotoxicity with a focus on risk and challenges at the ecological level and their risks to human health, along with the scientific and organizational levels. This study opens many windows in such studies nexus which are needed in the near future.

Analysis of Fluorescent Carbon Nanodot Formation during Pretzel Production.

Baked pretzels are a popular choice for a quick snack, easily identifiable by their classic twisted shape, glossy exterior, and small salt crystals sprinkled on top, making them a standout snack. However, it is not commonly known that compounds with fluorescent properties can be formed during their production. Carbon nanodots (CNDs) with an average size of 3.5 nm were isolated and identified in bakery products. This study delved into the formation of CNDs in pretzel production using a fractional factorial experimental design. The research revealed that the baking temperature had the most significant impact on the concentration of CNDs, followed by the concentration of NaOH in the immersion solution, and then the baking time. This study highlights the unique role of the NaOH immersion step, which is not typically present in bread-making processes, in facilitating the formation of CNDs. This discovery highlights the strong correlation between the formation of CNDs and the heat treatment process. Monitoring and controlling these factors is crucial for regulating the concentration of CNDs in pretzel production and understanding nanoparticle formation in processed foods for food safety.

Modulation of the Gut Microbiota with Prebiotics and Antimicrobial Agents from Pleurotus ostreatus Mushroom.

Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm mushroom contains bioactive compounds with both antimicrobial and prebiotic properties, which are distributed in the mushroom mycelium, fruiting body, and spent substrate. The mushroom is rich in nondigestible carbohydrates like chitin and glucan, which act as prebiotics and support the growth and activity of beneficial gut bacteria, thereby maintaining a healthy balance of gut microbiota and reducing the risk of antibiotic resistance. The bioactive compounds in P. ostreatus mushrooms, including polysaccharides (glucans, chitin) and secondary metabolites (phenolic compounds, terpenoids, and lectins), exhibit antibacterial, antiviral, and antifungal activities. When mushrooms are consumed, these compounds can help preventing the growth and spread of harmful bacteria in the gut, reducing the risk of infections and the development of antibiotic resistance. Nonetheless, further research is necessary to determine the efficacy of P. ostreatus against different pathogens and to fully comprehend its prebiotic and antimicrobial properties. Overall, consuming a diet rich in mushroom-based foods can have a positive impact on human digestion health. A mushroom-based diet can support a healthy gut microbiome and reduce the need for antibiotics.

A Covalently Crosslinked Ink for Multimaterials Drop-on-Demand 3D Bioprinting of 3D Cell Cultures.

In vitro 3D cell models have been accepted to better recapitulate aspects of in vivo organ environment than 2D cell culture. Currently, the production of these complex in vitro 3D cell models with multiple cell types and microenvironments remains challenging and prone to human error. Here, a versatile ink comprising a 4-arm poly(ethylene glycol) (PEG)-based polymer with distal maleimide derivatives as the main ink component and a bis-thiol species as the activator that crosslinks the polymer to form the hydrogel in less than a second is reported. The rapid gelation makes the polymer system compatible with 3D bioprinting. The ink is combined with a novel drop-on-demand 3D bioprinting platform, designed specifically for producing 3D cell cultures, consisting of eight independently addressable nozzles and high-throughput printing logic for creating complex 3D cell culture models. The combination of multiple nozzles and fast printing logic enables the rapid preparation of many complex 3D cell cultures comprising multiple hydrogel environments in one structure in a standard 96-well plate format. The platform's compatibility for biological applications is validated using pancreatic ductal adenocarcinoma cancer (PDAC) and human dermal fibroblast cells with their phenotypic responses controlled by tuning the hydrogel microenvironment.

Porous Graphene Oxide Films Prepared via the Breath-Figure Method: A Simple Strategy for Switching Access of Redox Species to an Electrode Surface.

Porous materials can be modified with physical barriers to control the transport of ions and molecules through channels via an external stimulus. Such capability has brought attention toward drug delivery, separation methods, nanofluidics, and point-of-care devices. In this context, gated platforms on which access to an electrode surface of species in solution can be reversibly hindered/unhindered on demand are appearing as promising materials for sensing and microfluidic switches. The preparation of a reversible gated device usually requires mesoporous materials, nanopores, or molecularly imprinted polymers. Here, we show how the breath-figure method assembly of graphene oxide can be used as a simple strategy to produce gated electrochemical materials. This was achieved by forming an organized porous thin film of graphene oxide onto an ITO surface. Localized brushes of thermoresponsive poly(N-isopropylacrylamide) were then grown to specific sites of the porous film by in situ reversible addition-fragmentation chain-transfer polymerization. The gating mechanism relies on the polymeric chains to expand and contract depending on the thermal stimulus, thus modulating the accessibility of redox species inside the pores. The resulting platform was shown to reversibly hinder or facilitate the electron transfer of solution redox species by modulating temperature from the room value to 45 °C or vice versa.

Preoperative Glycosylated Hemoglobin and Postoperative Glucose Together Predict Major Complications after Abdominal Surgery.

BACKGROUND: Glycosylated hemoglobin (HbA1c) is diagnostic of and a measure of the quality of control of diabetes mellitus. Both HbA1c and perioperative hyperglycemia have been targeted as modifiable risk factors for postoperative complications. The HbA1c percent cutoff that best predicts major complications has not been defined. STUDY DESIGN: A prospective study of all abdominal operations from a single institution from 2007 to 2010 was performed. All patients with HbA1c within 3 months before surgery were included. The primary end point was major complication, using the Clavien-Dindo complication system, within 30 days of surgery. Stepwise, multivariate analysis was performed including clinically relevant variables chosen a priori. RESULTS: Among 438 patients who had a measured HbA1c, 96 (21.9%) experienced a major complication. On multivariate analysis, HbA1c ≥ 6.5% (odds ratio = 1.95; 95% CI, 1.17-3.24; p = 0.01) was found to be the most significant predictor of major complications. Glyosylated hemoglobin and glucose were strongly correlated (correlation coefficient 0.414, p < 0.01). Predicted probabilities demonstrated that both HbA1c and glucose together contributed to major complications; and HbA1c impacted the ability to achieve optimal perioperative glucose control. Patients with a BMI >30 kg/m(2), history of coronary artery disease, and nonwhite race were more likely to have a HbA1c ≥ 6.5%. CONCLUSIONS: Elevated HbA1c ≥ 6.5% and perioperative hyperglycemia were associated with an increased rate of major complications after abdominal surgery. Elevated peak postoperative glucose levels were correlated with elevated HbA1c and were independently associated with major complications. More liberal HbA1c testing should be considered in high-risk patients before elective surgery. Safe, feasible, and effective strategies to reduce both HbA1c and perioperative hyperglycemia need to be developed to optimize patient outcomes.

Development and validation of a risk stratification score for ventral incisional hernia after abdominal surgery: hernia expectation rates in intra-abdominal surgery (the HERNIA Project).

BACKGROUND: Ventral incisional hernias (VIH) develop in up to 20% of patients after abdominal surgery. No widely applicable preoperative risk-assessment tool exists. We aimed to develop and validate a risk-assessment tool to predict VIH after abdominal surgery. STUDY DESIGN: A prospective study of all patients undergoing abdominal surgery was conducted at a single institution from 2008 to 2010. Variables were defined in accordance with the National Surgical Quality Improvement Project, and VIH was determined through clinical and radiographic evaluation. A multivariate Cox proportional hazard model was built from a development cohort (2008 to 2009) to identify predictors of VIH. The HERNIAscore was created by converting the hazards ratios (HR) to points. The predictive accuracy was assessed on the validation cohort (2010) using a receiver operator characteristic curve and calculating the area under the curve (AUC). RESULTS: Of 625 patients followed for a median of 41 months (range 0.3 to 64 months), 93 (13.9%) developed a VIH. The training cohort (n = 428, VIH = 70, 16.4%) identified 4 independent predictors: laparotomy (HR 4.77, 95% CI 2.61 to 8.70) or hand-assisted laparoscopy (HAL, HR 4.00, 95% CI 2.08 to 7.70), COPD (HR 2.35; 95% CI 1.44 to 3.83), and BMI ≥ 25 kg/m(2) (HR1.74; 95% CI 1.04 to 2.91). Factors that were not predictive included age, sex, American Society of Anesthesiologists (ASA) score, albumin, immunosuppression, previous surgery, and suture material or technique. The predictive score had an AUC = 0.77 (95% CI 0.68 to 0.86) using the validation cohort (n = 197, VIH = 23, 11.6%). Using the HERNIAscore: HERNIAscore = 4(∗)Laparotomy+3(∗)HAL+1(∗)COPD+1(∗) BMI ≥ 25, 3 classes stratified the risk of VIH: class I (0 to 3 points),5.2%; class II (4 to 5 points),19.6%; and class III (6 points), 55.0%. CONCLUSIONS: The HERNIAscore accurately identifies patients at increased risk for VIH. Although external validation is needed, this provides a starting point to counsel patients and guide clinical decisions. Increasing the use of laparoscopy, weight-loss programs, community smoking prevention programs, and incisional reinforcement may help reduce rates of VIH.