Modeling interactions of Clostridium cadaveris and Clostridium sporogenes in anaerobic acidogenesis of glucose and peptone.

This study focuses on developing a mathematical model to assess interaction among acidogenic bacteria during the anaerobic degradation of two substrates. Clostridium cadaveris and Clostridium sporogenes were cultured in various combinations with glucose and peptone. Parameter estimates are given for both conventional Monod parameters from single substrate-single species cultures and sum kinetics with interaction parameters obtained from dual substrate-single species cultures. The presence of multiple substrates led to both inhibitory and enhancing effects on biodegradation rates for dual substrates compared to single substrate cultures. A new model of interspecies interaction was developed within the framework of Lotka-Volterra incorporating substrate interaction parameters, with a focus on accuracy, realism, simplicity, and biological significance. The model demonstrated competitive interaction for resource sharing and the additional non-linearity parameter eliminated the constraint of the linear relationship between growth rate and population density.

Laminating Structure for Interlayer Corona Discharge Treatment Toward Ion-Based Nanogenerators.

A corona discharge treatment (CDT) is utilized to maximize the performance of triboelectric nanogenerators (TENGs) by injecting extra electrons into the negative tribomaterials. Increased performance of CDT TENGs, however, exhibits rapid degradation due to the electron dissipation by air moisture or thermal emission. To overcome such drawbacks and circumvent such dissipation, the source of charges should be replaced with ionic charges. This study reports a Ag nanowires (NWs)-embedded laminating structure (AeLS) with a unique fabrication procedure for ionic charge injection by CDT. The injection of ions is achieved by interlayer-CDT (i-CDT), in which positive charges are dissipated by Ag NWs, and the opposite negative ions can remain on the outmost surface. The AeLS TENGs with i-CDT exhibit high performance, long-term stability, and durability. It shows voltage, current, and maximum power outputs of 380 V, 15 µA, and 827 mW m-2 , respectively. As a practical demonstration, rotational TENG integrated with a direct discharge system is realized, and its current and voltage reach 7.4 mA and 7800 V, respectively. This work can pave the way for the design of ion-based TENGs with high performance and long-lasting retention of triboelectric charges.

Prophylactic efficacy of Lactobacillus curvatus B67-derived postbiotic and quercetin, separately and combined, against Listeria monocytogenes and Salmonella enterica ser. Typhimurium on processed meat sausage.

This study investigated the antimicrobial and antibiofilm efficacy of separate and combined treatments of Lactobacillus curvatus B67-produced postbiotic and the polyphenolic flavanol quercetin against Listeria monocytogenes and Salmonella enterica ser. Typhimurium. The antimicrobial potentiality of the postbiotic was chiefly associated with organic acids (e.g., lactic and acetic acids). At sub-minimum inhibitory concentration (1/2 MIC), the postbiotic and quercetin effectively reduced the pathogenic biofilm cells on processed pork sausage and meat-processing surfaces (e.g., stainless-steel and rubber). Moreover, the postbiotic exhibited strong residual antimicrobial efficacy over diverse pH and temperature ranges. In addition, the combination of postbiotic with quercetin increased the leakage of pathogenic intracellular metabolites (e.g., nucleic acids and protein) and inhibited pathogenic biofilm formation on both biotic and abiotic surfaces. Therefore, this study confirmed that lactic acid bacteria-derived postbiotic and plant-derived quercetin could be used as potential alternative bioprotective agents in the meat processing industry.

Reversible electrical percolation in a stretchable and self-healable silver-gradient nanocomposite bilayer.

The reversibly stable formation and rupture processes of electrical percolative pathways in organic and inorganic insulating materials are essential prerequisites for operating non-volatile resistive memory devices. However, such resistive switching has not yet been reported for dynamically cross-linked polymers capable of intrinsic stretchability and self-healing. This is attributable to the uncontrollable interplay between the conducting filler and the polymer. Herein, we present the development of the self-healing, stretchable, and reconfigurable resistive random-access memory. The device was fabricated via the self-assembly of a silver-gradient nanocomposite bilayer which is capable of easily forming the metal-insulator-metal structure. To realize stable resistive switching in dynamic molecular networks, our device features the following properties: i) self-reconstruction of nanoscale conducting fillers in dynamic hydrogen bonding for self-healing and reconfiguration and ii) stronger interaction among the conducting fillers than with polymers for the formation of robust percolation paths. Based on these unique features, we successfully demonstrated stable data storage of cardiac signals, damage-reliable memory triggering system using a triboelectric energy-harvesting device, and touch sensing via pressure-induced resistive switching.

Actual compliance rate of Enhanced Recovery After Surgery protocol in laparoscopic distal gastrectomy.

Purpose: The Enhanced Recovery After Surgery (ERAS) protocol enhances recovery rate after laparoscopic distal gastrectomy (LDG). An ERAS protocol has been applied to most patients who underwent LDG at our center. In this study, we determined the actual compliance rate of the ERAS protocol and analyzed the risk factors for noncompliance. Methods: Medical records of 1,013 patients who underwent LDG from March 2016 to December 2017 were reviewed retrospectively. The compliance group (A) included 327 patients who were discharged within four days postoperatively. The noncompliance group (B) comprised 686 patients who were not discharged within four days postoperatively. Results: The compliance rate of the ERAS protocol was 32.3%. Potential compliance rate was 53.2%. Most common reasons for noncompliance were fever (n = 115) and ileus (n = 111). The 30-day emergency room visit rate was significantly lower in group A than that in group B (p = 0.006). Median age, American Society of Anesthesiologists (ASA) physical status classification, operation time, and pathologic stage were significantly higher in group B than those in group A (p < 0.001, p < 0.001, p = 0.005, and p < 0.001, respectively). Risk factors for noncompliance were ASA classification of ≥III (odds ratio [OR], 2.251; p = 0.007), age of ≥70 years (OR, 1.572; p = 0.004), operation time of ≥180 minutes (OR, 1.475; p = 0.003), and pathologic stage of ≥III (OR, 2.224; p < 0.001). Conclusion: The current ERAS protocols should be applied to patients without risk factors.