Initial Activity Research Articles

Kinetic Insights into the Mechanism of Oxygen Reduction Reaction on Fe2O3 /C Composites

Electrochemical energy storage and conversion systems are the appealing replacement for nonrenewable resources to provide clean and sustainable energy. Of particular interest are fuel cells and metal-air batteries, both of which rely on the oxygen reduction reaction (ORR) for their operation. Fe-N-C catalyst has been widely used as a prominent catalyst towards ORR, but there is still some ambiguity regarding its active sites. This study describes the role of Fe2O3, an inevitable species formed in Fe-N-C catalyst towards the ORR. The Fe2O3 is carefully synthesised on various carbon supports and characterised using XPS spectra, HRTEM images, and surface area analysis. The particle size of the Fe2O3 nanoparticles synthesised on the pores of the carbon support was determined to be ~10 nm from the HRTEM analysis. The current density of ORR and the number of electrons transferred on Fe2O3/C catalysts is increased compared with bare carbon supports. Based on the kinetic analysis, the ORR on Fe2O3/C follows pseudo-4-electron (or) 2+2-electron ORR, where the first 2-electron ORR to H2O2 and second 2-electron H2O2 reduction reaction (HPRR) to H2O are assigned to the graphitic carbon (carbon defects) and Fe2O3 active sites, respectively. The role of Fe2O3 is further studied using the Theoretical method, which reveals the decreased formation of free energy of O2 adsorption. The Fe2O3 reduces the energy barrier for the reduction of *OOH to OH-. The Fe2O3/C shows higher stability by retaining 95% of the initial activity even after 20,000 cycles. Figure 1

Improved Activity and Durability of Carbon-Coated Pd and PdNi Anode Catalysts in AEMFC

Anion exchange membrane fuel cells (AEMFC) have received growing attention due to the strategic potential of using low content (or absence) of PGM catalysts in the electrodes.[1] Completely PGM-free cathode catalysts are well established in those conditions,[2] while the anode ones remain critical in terms of the beginning-of-life activity and long-term performance.[3] The widely Pt- and Pd-based catalysts degrade mainly by nanoparticles detachment and agglomeration in alkaline conditions.[4] These degradations may be slowed down by wrapping the nanoparticles in some carbon layers (called carbon-coated), that prevent also metal oxidation and leaching into the electrolyte in the RDE setup.[5] However, the performance in AEMFC of carbon-coated nanoparticle catalysts is still unclear.Here, two groups (previously characterized in RDE, XRD, IL-TEM, XPS and ICP-MS techniques[5]) of carbon-coated catalysts were investigated in 5 cm2 AEMFC: monometallic Pd (Pd@C/C) and bimetallic PdNi (PdNi@C/C) nanoparticles supported on carbon, and compared them to unprotected ones (Pd/C and PdNi/C). The four different anode catalysts were compared for a fixed Pd anode loading of 0.27 mgPd cm-2, and were combined with a ZIF-8 derived Fe-N-C cathode catalyst (previously developed Fe0.5-NH3). The Pd@C/C and PdNi@C/C reached superior initial performances (700 and 1300 mA cm-2) than the Pd/C and PdNi/C references (300 and 390 mA cm-2) at 0.6 V and Tcell = 60 °C. This translates into an initial activity trend of PdNi@C/C > PdNi/C > Pd@C/C > Pd/C. After 12 h durability test at a cell voltage of 0.3 V, the AEMFC with the PdNi@C/C based anode exhibits a dramatically higher retention of performance (95%) than the cells with Pd/C (55%) and PdNi/C (70%) anodes. These results evidence the robustness of bimetallic carbon-coated nanoparticle catalysts for AEMFC anodes. Figure 1

Novel Electrode Designs and Configurations in Secondary Iron-Air Batteries

Stationary energy storage solutions are urgently needed due to the challenges we face caused by the anthropogenic climate change. While Lithium-Ion batteries are still considered as state of the art within this field, the availability of lithium is limited.The iron-air battery system is mainly superior due to the low criticality of the active materials. Iron is cheap and abundant, while air is supplied by the ambient atmosphere. During discharging oxygen from ambient air is reduced (oxygen reduction reaction, ORR) and evolved during charging (oxygen evolution reaction, OER). One of the main challenges towards stable metal-air batteries is the air-electrode. Those usually consist of a catalyst, a conductive additive, and – depending on the electrode design- of a binder. Carbon-based materials offer an excellent intrinsic activity towards the oxygen reduction and a high specific surface area. However, carbon corrodes in the potential range of the oxygen evolution reaction. Our work focuses on the development of novel electrode formulations for PTFE-bonded electrodes and novel self-supported electrode structures - based on galvanic deposition of nickel - and their implementation in iron-air batteries.Within a first approach a mixed catalyst composed of MnO2 and NiO was investigated in a PTFE-bonded electrode with nickel as conductive additive. The electrode reached an initial activity of 0.77 V vs. RHE @ -25 mA cm-2 (ORR) and 1.57 V vs. RHE @ 25 mA cm-2 (OER) in 6 M KOH at room temperature. The potentials were stable for about 60 cycles (one cycle consisted of 60 min). MnO2 corrodes at OER potentials, which results in a decrease of activity. However, a partial substitution of MnO2 by NiO is beneficial for the cycling stability. In a second approach, a bifunctional nickel-cobalt-oxide based bifunctional catalyst was investigated within the same electrode system. An initial activity of 0.71 V vs. RHE and 1.63 V vs. RHE was observed for this system. Stable OER performance but a decrease ORR activity was observed within this system over time during cycling. To increase the cycling stability, dendritic nickel structures with a high intrinsic surface area were prepared with galvanic deposition. Our results indicate that the efficiency and stability of the battery can be improved by using this approach. Figure 1

Controllable lignin valorization to value-added aromatic chemicals by a UV-assisted ternary heterogeneous photo-fenton catalytic system

Photocatalysis, which leverages sustainable solar energy to facilitate the conversion of lignin under mild conditions, has gained considerable research interest. Therefore, our study introduces a novel heterogeneous photo-Fenton reagent, Fe3O4@GO@TiO2, designed to selectively depolymerize lignin into aromatic chemicals using ultraviolet light as the energy source. This ternary photo-Fenton catalyst could effectively depolymerize approximately 90% of lignin model compounds. The model compounds without or with phenolic OH blocking yield guaiacol exclusively and predominantly guaiacol with aromatic aldehydes, respectively. The lignin degradation mechanism using the photo-Fenton catalyst (Fe3O4@GO@TiO2) involves the formation of an enol ether intermediate, followed by the cleavage of lignin β-O-4 bonds, facilitated by a mild photon-stimulated reduction–oxidation Fenton process. Notably, the reduced GO plays a crucial role in two aspects. Firstly, it transfers and stabilizes the photoexcited electron-hole pairs. Secondly, it promotes the generation of radicals (•OH, •OOH) essential for selective degradation of the lignin side chains. Consequently, the average molecular weight of the lignin depolymerized product is half of that of the original lignin. Furthermore, this photocatalyst demonstrates recyclability, retaining 85% of its initial activity after five-time recycling. This tertiary Fenton-photocatalyst provides a novel approach for the selective depolymerization of lignin interunit bonds into valuable phenolic monomers under ambient conditions.

Plectasin: from evolution to truncation, expression, and better druggability.

Non-computational classical evolution analysis of plectasin and its functional relatives can especially contribute tool value during access to meet requirements for their better druggability in clinical use. Staphylococcus aureus is a zoonotic pathogen that can infect the skin, blood, and other tissues of humans and animals. The impact of pathogens on humans is exacerbated by the crisis of drug resistance caused by the misuse of antibiotics. In this study, we analyzed the evolution of anti-Staphylococcus target functional sequences, designed a series of plectasin derivatives by truncation, and recombinantly expressed them in Pichia pastoris X-33, from which the best recombinant Ple-AB was selected for the druggability study. The amount of total protein reached 2.9 g/L following 120 h of high-density expression in a 5-L fermenter. Ple-AB was found to have good bactericidal activity against gram-positive bacteria, with minimum inhibitory concentration (MIC) values ranging between 2 and 16 μg/mL. It showed good stability and maintained its bactericidal activity during high temperatures, strong acid and alkali environments. Notably, Ple-AB exhibited better druggability, including excellent trypsin resistance, and still possessed approximately 50% of its initial activity following exposure to simulated intestinal fluids for 1 h. In vitro safety testing of Ple-AB revealed low hemolytic activity against mouse erythrocytes and cytotoxicity against murine-derived macrophages. This study successfully realized the high expression of a new antimicrobial peptide (AMP), Ple-AB, in P. pastoris and the establishment of its oral administration as an additive form with high trypsin resistance; the study also revealed its antibacterial properties, indicating that truncation design is a valuable tool for improving druggability and that the candidate Ple-AB may be a novel promising antimicrobial agent.

Characterization of a thermophilic and glucose-tolerant GH1 β-glucosidase from hot springs and its prospective application in corn stover degradation.

β-Glucosidase serves as the pivotal rate-limiting enzyme in the cellulose degradation process, facilitating the hydrolysis of cellobiose and cellooligosaccharides into glucose. However, the widespread application of numerous β-glucosidases is hindered by their limited thermostability and low glucose tolerance, particularly in elevated-temperature and high-glucose environments. This study presents an analysis of a β-glucosidase gene belonging to the GH1 family, denoted lqbg8, which was isolated from the metagenomic repository of Hehua hot spring located in Tengchong, China. Subsequently, the gene was cloned and heterologously expressed in Escherichia coli BL21(DE3). Post expression, the recombinant β-glucosidase (LQBG8) underwent purification through a Ni affinity chromatography column, thereby enabling the in-depth exploration of its enzymatic properties. LQBG8 had an optimal temperature of 70°C and an optimum pH of 5.6. LQBG8 retained 100 and 70% of its maximum activity after 2-h incubation periods at 65°C and 70°C, respectively. Moreover, even following exposure to pH ranges of 3.0-10.0 for 24 h, LQBG8 retained approximately 80% of its initial activity. Notably, the enzymatic prowess of LQBG8 remained substantial at glucose concentrations of up to 3 M, with a retention of over 60% relative activity. The kinetic parameters of LQBG8 were characterized using cellobiose as substrate, with Km and Vmax values of 28 ± 1.9 mg/mL and 55 ± 3.2 μmol/min/mg, respectively. Furthermore, the introduction of LQBG8 (at a concentration of 0.03 mg/mL) into a conventional cellulase reaction system led to an impressive 43.7% augmentation in glucose yield from corn stover over a 24-h period. Molecular dynamics simulations offered valuable insights into LQBG8's thermophilic nature, attributing its robust stability to reduced fluctuations, conformational changes, and heightened structural rigidity in comparison to mesophilic β-glucosidases. In summation, its thermophilic, thermostable, and glucose-tolerant attributes, render LQBG8 ripe for potential applications across diverse domains encompassing food, feed, and the production of lignocellulosic ethanol.

INTERPROFESSIONAL CO-LEARNING AT MULTIPLE LEVELS OF LTSS: PRO-HOME PROGRAMS AND RESEARCH

Abstract Promoting Seniors’ Health with Home Care Aides (Pro-Home), a randomized controlled trial (RCT) of a gentle physical activity program delivered by home care aides (HCAs) for their older clients in English or Spanish, provided unprecedented opportunities for collaboration and co-learning across multiple disciplines and professions (public health, health services research, sociology, medicine, physical/occupational therapy, kinesiology, social work, psychology, economics, medicine, nursing; frontline care workers, leaders and staff members of state and home care agencies, , social service agencies, researchers, undergraduate and graduate students). The turbulent long-term services and supports (LTSS) environment, which culminated in the COVID-19 pandemic, provided the study participants (HCAs and their older clients), multiple levels of LTSS stakeholders and the research team with rapidly evolving new contexts for the RCT. This paper presents how the Pro-Home project developed into a learning organization where individuals and organizations learn from each other to pivot at every new turn in the environment, focusing on the development of a novel interactive training for HCAs in-person or remotely. The initial training activities were conducted in-person. After adapting the material for remote delivery, we provided the latter sessions via phone with digital and physical tools. For each training session, we assessed outcome quality using an exit survey and other methods capturing HCAs’ program delivery. The presentation concludes with implications for research and practice in LTSS.

Gallic acid ameliorates colitis by trapping deleterious metabolite ammonia and improving gut microbiota dysbiosis.

Gut microbiota dysbiosis is causally related to inflammatory bowel disease (IBD), and increased levels of the gut metabolite ammonia have been proposed to contribute to IBD development. In this study, we aimed to clarify the anti-colitis mechanism of gallic acid (GA) based on its ability to trap the deleterious metabolite ammonia and improve gut microbiota. Aminated product was detected in the fecal samples of mice after oral gavage of gallic acid (GA) and identified as 4-amino-substituted gallic acid (4-NH2-GA), thus confirming the ability of GA to trap ammonia in vivo. Then, we compared the beneficial effects of GA and 4-NH2-GA on dextran sulfate sodium (DSS)-induced colitis mouse and found that both compounds managed to alleviate colitis phenotypes, indicating ammonia trapping had no adverse effect on the original anti-colitis activity of GA. In addition, both GA and 4-NH2-GA improved the gut microbiota dysbiosis induced by DSS, and fecal microbiota transplantation was subsequently performed, which further revealed that the gut microbiota mediated the anti-colitis activity of both GA and 4-NH2-GA. In summary, this study clarified that GA alleviated colitis by targeting both the symptoms and root causes: it directly reduced the deleterious metabolite ammonia by forming aminated metabolites without compromising the original anti-colitis activity, and it also improved gut microbiota dysbiosis, which in turn contributed to the alleviation of colitis. Since the GA structure is presented in various polyphenols as a common building block, the novel anti-colitis mechanism obtained from GA may also apply to other complex polyphenols.IMPORTANCEThe dysbiosis of the gut microbiota and its metabolism directly cause the emergence of IBD. In this study, we aimed to clarify the anti-colitis mechanism of GA in sight of gut microbiota and its metabolite ammonia. We discovered that GA directly captured and reduced the harmful metabolite ammonia in vivo to produce the aminated metabolite 4-NH2-GA, while the amination of GA had no adverse effect on its initial anti-colitis activity. In addition, both GA and its aminated metabolite improved the gut microbiota in colitis mice, and the modified gut microbiota, in turn, helped to relieve colitis. Since the GA structure is presented in diverse polyphenols as a common building block, the novel anti-colitis mechanism targeting the symptoms and root causes might also apply to other complex polyphenols.

The crystal structure of RsSymEG1 reveals a unique form of smaller GH7 endoglucanases alongside GH7 cellobiohydrolases in protist symbionts of termites.

Glycoside hydrolase family 7 (GH7) cellulases are key enzymes responsible for carbon cycling on earth through their role in cellulose degradation and constitute highly important industrial enzymes as well. Although these enzymes are found in a wide variety of evolutionarily distant organisms across eukaryotes, they exhibit remarkably conserved features within two groups: exo-acting cellobiohydrolases and endoglucanases. However, recently reports have emerged of a separate clade of GH7 endoglucanases from protist symbionts of termites that are 60-80 amino acids shorter. In this work, we describe the first crystal structure of a short GH7 endoglucanase, RsSymEG1, from a symbiont of the lower termite Reticulitermes speratus. A more open flat surface and shorter loops around the non-reducing end of the cellulose-binding cleft indicate enhanced access to cellulose chains on the surface of cellulose microfibrils. Additionally, when comparing activities on polysaccharides to a typical fungal GH7 endoglucanase (Trichoderma longibrachiatum Cel7B), RsSymEG1 showed significantly faster initial hydrolytic activity. We also examine the prevalence and diversity of GH7 enzymes that the symbionts provide to the termite host, compare overall structures and substrate binding between cellobiohydrolase and long and short endoglucanase, and highlight the presence of similar short GH7s in other organisms.

Eco-friendly synthesis of biochar supported with zinc oxide as a heterogeneous catalyst for photocatalytic decontamination of Rhodamine B under sunlight illumination

In the current study, biochar, as a porous and low-cost carbon derived from Pontederia crassipes L. leaves, was loaded with zinc oxide for the photocatalytic discoloration of Rhodamine B dye in aqueous suspension under solar light irradiation. For the comparison, the unmodified zinc oxide and biochar samples were prepared. The synthesizing materials were investigated by X-ray powder diffraction, UV-DRS spectrophotometer, field emission scanning electron microscopy, Fourier transform infrared spectrometer, and Raman spectroscopy. The synthesized ZnO/Biochar hybrid has improved features, besides narrowing the band gap energy, and enhancing the surface area of the photocatalyst. The ZnO/biochar nanohybrid displayed an excellent photocatalytic degradation efficiency (99. 67 %) of Rhodamine B in the presence of H2O2 with 120 min of solar light irradiation. The results of recyclability study of ZnO/Biochar in the photocatalysis process verified its physical and chemical stability after five repeated cycles, hence it retained of 82.24 % of initial activity. Furthermore, the photocatalytic discoloration reaction was compatible with the pseudo-first-order kinetic model

Comparison of bioaugmentation and biostimulation approaches for biocementation in soil column experiments

Microbially induced carbonate precipitation (MICP) is an innovative soil improvement technology. In the past, the most widely used method was bioaugmentation. Recently, biostimulation has attracted the attention from many researchers. There may be differences in the treatment effect when different methods are used. In this study, the soil improvement effects of these two methods were compared. In the experiment, two different nutrients (yeast extract and beef extract) were used and the initial urease activity between bioaugmentation and biostimulation was controlled at a close level. The results showed that biostimulation was a more environmentally friendly, cost-effective and gentle method. Biostimulation can achieve more sustained mineralization. The samples treated with biostimulation showed higher calcium carbonate precipitation content (CCP), shear wave velocity (Vs) and unconfined compressive strength (UCS) for the same cementation treatment cycle. Yeast extract was found to be more effective than beef extract in both bioaugmentation and biostimulation for the same cementation treatment cycle. However, the use of bioaugmentation and beef extract can result in higher soil strength for the same calcium carbonate precipitation content. This is related to the difference in CaCO3 crystal precipitation pattern using different treatment methods and nutrients. This study is expected to provide a basis for the selection of MICP treatment methods.

Faktor Pendukung dan Penghambat Penerapan Metode Jigsaw pada Mata Pelajaran IPS Kelas V di Sekolah Dasar

This research describes the supporting and obstacle factors in implementing the jigsaw method in social studies learning for grade V elementary schools. The type of research used is a case study with a descriptive qualitative approach. Data collection techniques are interviews, observation and documentation. The Miles and Huberman model data analysis technique which includes data reduction, data presentation, and data verification. The results of the research show that the supporting factors are the fulfillment of school facilities and infrastructure, as well as the active role of the school, both by teachers and school principals through programs that are able to increase teacher competence in relation to learning at school and the inhibiting factor is the jigsaw method which requires time old and smart students tend not to want to be put together. The application of the jigsaw method in class V social studies learning in elementary schools begins with the preparation of learning tools such as lesson plans. The implementation process carried out by the teacher in learning includes initial or opening activities, core activities and final activities. The initial activities were carried out by the teacher by providing motivation and apperception. In the core activity, the teacher implements the Jigsaw method through the steps that have been prepared. In the final activity, the teacher provides a conclusion. The evaluation process is carried out through written tests. The results show effectiveness in the learning process and are able to improve learning outcomes for students.

Assessing the production of galactooligosaccharides in batch and continuous mode by using β‐galactosidase immobilised on mesoporous silicon dioxide nanoparticles

SummaryThe present study evaluated the production of galactooligosaccharides (GOSs) from lactose in both batch and continuous modes using nano‐immobilised β‐galactosidase. Mesoporous silicon dioxide nanoparticles were used to immobilise β‐galactosidase to enhance the stability and production of GOSs. The change in enzyme‐characteristics was assessed using Fourier‐transform infrared and scanning electron microscope analysis. The nano‐immobilisation increased the enzyme's substrate affinity, but decreased its hydrolytic activity. A significant increase (P < 0.05) in stability was observed across a wide range of temperature (30 °C–70 °C) and pH (5.0–8.0). Both forms of enzymes (free and nano‐immobilised enzymes) followed the zero‐order reaction in all temperatures, while the nano‐immobilised enzyme had the highest activation energy. The free and nano‐immobilised enzymes retained 64.65% and 77.82% of their initial activity after 90 days of storage, respectively. In a batch mode, the nano‐immobilised enzyme produced 2.35 times more GOSs than the free enzyme. The GOSs production remained consistent while the enzyme activity decreased by 12.7% after 5 cycles of operation. The continuous mode of production in a packed bed reactor achieved a GOSs yield of 16.92%. Overall, the nano‐immobilised enzyme showed better GOSs production under batch and continuous mode of operation.

Cloning and expression of Neurospora crassa cellobiohydrolase II in Pichia pastoris

A major cellobiohydrolase of Neurospora crassa CBH2 was successfully expressed in Pichia pastoris. The maximum Avicelase activity in shake flask among seven transformants which selected on 4.0 g/L G418 plates was 0.61 U/mL. The optimal pH and temperature for Avicelase activity of the recombinant CBH2 were determined to be 4.8 and 60 °C, respectively. The new CBH2 maintained 63.5 % Avicelase activity in the range of pH 4.0–10.4, and 60.2 % Avicelase activity in the range of 30–90 °C. After incubation at 70–90 °C for 1 h, the Avicelase activity retained 60.5 % of its initial activity. The presence of Zn2+, Ca2+ or Cd2+ enhanced the Avicelase activity of the CBH2, of which Cd2+ at 10 mM causing the highest increase. The recombinant CBH2 was used to enhance the Avicel hydrolysis by improving the exo-exo-synergism between CBH2 and CBH1 in N.crassa cellulase. The enzymatic hydrolysis yield was increased by 38.1 % by adding recombinant CBH2 and CBH1, and the yield was increased by 215.4 % when the temperature is raised to 70 °C. This work provided a CBH2 with broader pH range and better heat resistance, which is a potential enzyme candidate in food, textile, pulp and paper industries, and other industrial fields.

Perilaku Hidup Bersih dan Sehat sebagai Langkah Pencegahan Diare pada Siswa Sekolah Dasar

PHBS is a set of behaviors that are practiced on the basis of awareness as an effort to be healthy and actively help the health of the surrounding environment. Clean and Healthy Behavior at an early age is important to to maintain personal and environmental health. Early childhood is also susceptible to infectious diseases such as flu and diarrhea if they do not maintain personal and surrounding hygiene. Diarrheal disease is often considered a trivial matter but if it is not addressed it can result in quite serious matters. Therefore, we conducted community services which aims to provide students knowledge and understanding about Clean and Healthy Behavior and diarrheal diseases which often attack children at Muhammadiyah 1 Malang Elementary School students. The implementation method is carried out by counseling using power point media and videos. In the initial activity, a question-and-answer session was carried out, then giving educational material, showing educational videos, then evaluating it with a posttest.

Analsisis Penerapan Media Pembelajaran dalam Proses Belajar Mengajar pada Jenjang Sekolah Dasar

Learning media in elementary schools is increasingly needed to facilitate the teaching and learning process. There is an urgency for learning media in elementary schools in the current digital era. First, increase the attractiveness of learning. Interactive and interesting learning media can provide a pleasant learning experience for students so that it can increase motivation and interest in learning. Second, increase the effectiveness of learning. Learning media can help students understand concepts more easily and quickly. Third, increase student participation. This can increase student involvement and participation in learning. Fourth, increase student creativity. Learning media with features such as image and video content can stimulate imagination and open up students' possibilities for creativity and innovation. Fourth, facilitate distance learning. Currently, in the COVID-19 pandemic situation, the use of learning media is very important to support distance learning in elementary schools. Therefore, the use of learning media in elementary schools in the current digital era needs to be implemented well and integrated into the curriculum, so that it can provide maximum benefits for students in the learning process. For this reason, this research focuses on analyzing the application of learning media in the learning and teaching process at the elementary school level. The aim of this research is to find out a clear picture of how learning media is implemented at the elementary school level, specifically in the West Kalimantan-Malaysia border area. The stages of the research method used are in the first stage, preparing data collection tools. The second stage in the research carried out was data collection and collection. The initial activity was observation by inspecting elementary schools in Bengkayang Regency. A literature review is carried out to look for data or source support that is relevant to the research. Interviews and Focus Group Discussions (FGD) will be conducted online and offline. The questionnaire that has been prepared will be shared online using Google Forms. The third or final stage is the stage of data preparation and recapitulation.Keywords: instructional media, elementary school

Two-Pronged Dormant Photosensitizer-Antibiotic Bacterial Inactivation: Mechanism, Dosage, and Cellular Evolution Visualized at the Single-Cell Level.

Innovative therapeutic approaches are required to battle the rise of antibiotic-resistant bacterial strains. Tapping on reactive oxygen species (ROS) generation in bacteria induced by bactericidal antibiotics, here we report a two-pronged strategy for bacterial inactivation relying on the synergistic combination of a bactericidal antibiotic and newly designed dormant photosensitizers (DoPSs) that activate in the presence of ROS. Intramolecular quenching renders DoPS inert in the presence of light. ROS trapping by DoPS aborts the quenching mechanism unmasking, in equal proportions, singlet oxygen (1O2) sensitization and fluorescence emission. Juxtaposed antioxidant-prooxidant activity built within our DoPS enables (i) initial activation of a few molecules by ROS and (ii) subsequent rapid activation of all DoPS in a bacterium via a domino effect mediated by photogenerated 1O2. Bulk colony forming unit studies employing the minimum inhibitory concentration of the antibiotic illustrate rapid and selective inactivation of Escherichia coli and Pseudomonas aeruginosa only in the presence of light, antibiotic, and DoPS. Single-cell, real-time imaging studies on E. coli reveal an autocatalytic progression of DoPS activation from focal points, providing a unique amplification system for sensing. Single-cell analysis further illustrates the impact of DoPS cellular loading on the rate of DoPS activation and cell death times and on the 1O2 dosing necessary for cell death to occur. Our two-pronged therapy discriminates based on cell metabolites and has the potential to result in lower toxicity, pave the way to reduced drug resistance, and provide insightful mechanistic information about bacterial membrane response to 1O2.

Muscle activation and coordinated movements of infant rolling

Rolling is a critical step of infant development, encouraging muscle coordination and enabling independent exploration. Understanding muscle activity during infant rolling movements on a flat surface is necessary to more fully characterize how the rolling milestone is achieved. The purpose of this study was to determine infants’ muscle activation throughout roll initiation for six previously established coordinated movements. Thirty-eight healthy infants (age: 6.5 ± 0.7 months; 23M/15F) were enrolled in this IRB-approved in-vivo biomechanics study. Surface electromyography sensors recorded muscle utilization from the erector spinae, abdominal muscles, quadriceps, and hamstrings while infants rolled. Each rolling movement was categorized as one of six roll types, and the mean muscle activity was analyzed. All roll types required initial activation of all measured muscle groups. Movements featuring axial rotation of the torso relative to the pelvis required highly active erector spinae muscles. Movements featuring trunk and hip flexion required highly active abdominal muscles. Infants used distinct coordinated muscle activations to achieve the six different roll types on a flat surface. A foundational understanding of the different muscle activation patterns required during infant rolling will provide crucial insight into motor development. This study quantified muscle coordination required of infants to achieve rolling on a firm flat surface. Previous research indicates that the mechanical environment in which an infant is placed impacts muscle activity and body position during normal lying. Therefore, future work should explore if mechanical environments that differ from a flat and firm surface also influence these coordinated movements and muscle activations.

Clinical correlation of cholelithiasis in patients undergoing percutaneous endoscopic gastrostomy

The risk factor for cholelithiasis include low physical activity. With an aging society, the number of bedridden patients who undergo percutaneous endoscopic gastrostomy (PEG) has increased, and cholelithiasis has often been found in these patients. This study aimed to evaluate the risk factors correlated with cholelithiasis in adults who underwent PEG. This retrospective single-center design study reviewed patients who underwent PEG and were confirmed to have cholelithiasis through imaging from March 1996 to December 2021. The investigated variables were age, sex, body mass index (BMI, kg/m2), cause of PEG insertion, initial physical activity status, laboratory findings on PEG insertion day, and incidence of acute cholecystitis. The differences between categorical and continuous variables were analyzed using Student’s t test and chi-square test. We enrolled 576 eligible patients who underwent PEG insertion. A total of 161 patients were detected with cholelithiasis (28.0%). The overall independent risk factors for cholelithiasis in patients who underwent PEG insertion were increased C-reactive protein (CRP) levels and decreased physical activity status (bedridden state). The incidence of cholelithiasis was increased by up to 30.7%, especially in patients with bedridden status. However, the incidence of acute cholecystitis among cholelithiasis group was only 5.6%. BMI and total cholesterol were positively correlated with the size of gallbladder (GB) stones. One of the major risk factors for cholelithiasis is decreased physical activity, especially in patients who underwent PEG insertion. Abdominal imaging is recommended to confirm the presence of cholelithiasis and to consider prophylaxis for cholelithiasis, especially in bedridden patients with elevated initial CRP levels at the time of PEG insertion.

The association between electrode impedance and short-term outcomes in cochlear implant recipients of slim modiolar and slim straight electrode arrays

Objectives Electrode impedance measurements from cochlear implants (CI) reflect the status of the electrode array as well as the surrounding cochlear environment, and could provide a clinical index of functional changes with the CI. The goals of this study were to examine (1) the impact of electrode array type on electrode impedance, and (2) the relationship between electrode impedance and short-term hearing preservation and speech recognition outcomes. Methods Retrospective study of 115 adult hearing preservation CI recipients of a slim modiolar or slim straight array. Common ground electrode impedances, pre- and post-operative hearing thresholds and CNC word recognition scores were retrieved. Results Electrode impedances were significantly higher for recipients of the straight electrode array. Within individuals, electrode impedances were stable after the first week post-activation. However, increased standard deviation of electrode impedances was associated with greater loss of low frequency hearing at initial activation, and with poorer speech recognition at 6 months post-implantation. Conclusions Results demonstrate that electrode impedances depend on the type of implanted array. Findings also suggest that there may be a role for the variability in electrode impedance across electrodes as an indicator of changes in the intracochlear environment that contribute to outcomes with a CI.