Confined VLS Growth of Single-Layer 2D Tungsten Nitrides.

Two-dimensional (2D) metal nitrides have garnered significant interest due to their potential applications in future electronics and quantum systems. However, the synthesis of such materials with sufficient uniformity and at relevant scales remains an unaddressed challenge. This study demonstrates the potential of confined growth to control and enhance the morphology of 2D metal nitrides. By restricting the reaction volume of vapor-liquid-solid reactions, an enhanced precursor concentration was achieved that reduces the nucleation density, resulting in larger grain sizes and suppression of multilayer growth. Detailed characterization reveals the importance of balancing the energetic and kinetic aspects of tungsten nitride formation toward this ability. The introduction of a promoter enabled the realization of large-scale, single-layer tungsten nitride with a uniform and high interfacial quality. Finally, our advance in morphology control was applied to the production of edge-enriched 2D tungsten nitrides with significantly enhanced hydrogen evolution ability, as indicated by an unprecedented Tafel slope of 55 mV/dec.

Tungsten Nitride (W5N6): An Ultraresilient 2D Semimetal.

Two-dimensional transition metal nitrides offer intriguing possibilities for achieving novel electronic and mechanical functionality owing to their distinctive and tunable bonding characteristics compared to other 2D materials. We demonstrate here the enabling effects of strong bonding on the morphology and functionality of 2D tungsten nitrides. The employed bottom-up synthesis experienced a unique substrate stabilization effect beyond van-der-Waals epitaxy that favored W5N6 over lower metal nitrides. Comprehensive structural and electronic characterization reveals that monolayer W5N6 can be synthesized at large scale and shows semimetallic behavior with an intriguing indirect band structure. Moreover, the material exhibits exceptional resilience against mechanical damage and chemical reactions. Leveraging these electronic properties and robustness, we demonstrate the application of W5N6 as atomic-scale dry etch stops that allow the integration of high-performance 2D materials contacts. These findings highlight the potential of 2D transition metal nitrides for realizing advanced electronic devices and functional interfaces.

Association between the mental domain of the comprehensive geriatric assessment and prolonged length of stay in hospitalized older adults with mild to moderate frailty.

Introduction: Previous researches have shown the risk factors of prolonged length of stay (PLOS) in hospitalized older adults, but it is unclear what are the risk factors of PLOS in hospitalized older adults with mild to moderate frailty. Objective: To identify the risk factors of PLOS in hospitalized older adults with mild to moderate frailty. Methods: We recruited adults aged ≥65 years old with mild to moderate frailty admitted to a tertiary medical center in the southern Taiwan from June 2018 to September 2018. Each individual underwent a structural questionnaire interview within 72 h after admission and 72 h after discharge. The data were collected face-to-face, including demographic characteristics, comorbidities, length of stay (LOS), and multiple domains of the comprehensive geriatric assessment. The main outcome was PLOS. Results: Individuals who had two or more drugs, were female, did not have cognitive impairment and had a Geriatric Depression Scale score ≥ 1 had a higher risk of PLOS (probability = 0.81), and these individuals accounted for 29% of the overall study population. Among male individuals younger than 87 years old, those with cognitive impairment had a higher risk of PLOS (probability = 0.76), and among male individuals without cognitive impairment, living alone was associated with a higher risk of PLOS (probability = 0.88). Conclusion: Early detection and management of mood and cognition in older adults, together with comprehensive discharge planning and transition care, may be an important part of reducing LOS in hospitalized older adults with mild to moderate frailty.

Characterization of host and escherichia coli strains causing recurrent urinary tract infections based on molecular typing.

BACKGROUND: Escherichia coli is the leading pathogen responsible for urinary tract infection (UTI) and recurrent UTI (RUTI). Few studies have dealt with the characterization of host and bacteria in RUTI caused by E. coli with genetically identical or different strains. This study aimed to investigate the host and bacterial characteristics of E. coli RUTI based on molecular typing. RESULTS: Patients aged 20 years or above who presented with symptoms of UTI in emergency department or outpatient clinics between August 2009 and December 2010 were enrolled. RUTI was defined as patients had 2 or more infections in 6 months or 3 or more in 12 months during the study period. Host factors (including age, gender, anatomical/functional defect, and immune dysfunction) and bacterial factors (including phylogenicity, virulence genes, and antimicrobial resistance) were included for analysis. There were 41 patients (41%) with 91 episodes of E. coli RUTI with highly related PFGE (HRPFGE) pattern (pattern similarity > 85%) and 58 (59%) patients with 137 episodes of E. coli RUTI with different molecular typing (DMT) pattern, respectively. There was a higher prevalence of phylogenetic group B2 and neuA and usp genes in HRPFGE group if the first episode of RUTI caused by HRPFGE E. coli strains and all episodes of RUTI caused by DMT E. coli strains were included for comparison. The uropathogenic E. coli (UPEC) strains in RUTI were more virulent in female gender, age < 20 years, neither anatomical/ functional defect nor immune dysfunction, and phylogenetic group B2. There were correlations among prior antibiotic therapy within 3 months and subsequent antimicrobial resistance in HRPFGE E. coli RUTI. The use of fluoroquinolones was more likely associated with subsequent antimicrobial resistance in most types of antibiotics. CONCLUSIONS: This study demonstrated that the uropathogens in RUTI were more virulent in genetically highly-related E. coli strains. Higher bacterial virulence in young age group (< 20 years) and patients with neither anatomical/functional defect nor immune dysfunction suggests that virulent UPEC strains are needed for the development of RUTI in healthy populations. Prior antibiotic therapy, especially the fluoroquinolones, within 3 months could induce subsequent antimicrobial resistance in genetically highly-related E. coli RUTI.

Hyaluronic acid/platelet rich plasma-infused core-shell nanofiber membrane to prevent postoperative tendon adhesion and promote tendon healing.

An anti-adhesive barrier membrane incorporating hyaluronic acid (HA) can reduce fibroblasts attachment and impart lubrication effect for smooth tendon gliding during management of post-surgical tendon adhesion. On the other hand, as numerous growth factors are required during tendon recovery, growth factors released by platelets in platelet-rich plasma (PRP) can provide beneficial therapeutic effects to facilitate tendon recovery post tendon injury. Furthermore, PRP is reported to be associated with anti-inflammatory properties for suppressing postoperative adhesion. Toward this end, we fabricate core-shell nanofiber membranes (NFM) with HA/PRP-infused core and polycaprolactone shell in this study. Different NFM with 100 % (H-P), 75 % (HP31-P), 50 % (HP11-P) and 25 % (H31-P) HA in the core was fabricated through coaxial electrospinning and analyzed through microscopic, pore size, mechanical, as well as HA and growth factor release studies. In vitro study with fibroblasts indicates the NFM can act as a barrier to prevent cell penetration and reduce cell attachment/focal adhesion, in addition to promoting tenocyte migration in tendon healing. In vivo studies in a rabbit flexor tendon rupture model indicates the HP11-P NFM shows improved efficacy over H-P NFM and control in reducing tendon adhesion formation and inflammation, while promoting tendon healing, from functional assays and histological analysis.

Machine learning to predict the development of recurrent urinary tract infection related to single uropathogen, Escherichia coli.

Recurrent urinary tract infection (RUTI) can damage renal function and has impact on healthcare costs and patients' quality of life. There were 2 stages for development of prediction models for RUTI. The first stage was a scenario in the clinical visit. The second stage was a scenario after hospitalization for urinary tract infection caused by Escherichia coli. Three machine learning models, logistic regression (LR), decision tree (DT), and random forest (RF) were built for the RUTI prediction. The RF model had higher prediction accuracy than LR and DT (0.700, 0.604, and 0.654 in stage 1, respectively; 0.709, 0.604, and 0.635 in stage 2, respectively). The decision rules constructed by the DT model could provide high classification accuracy (up to 0.92 in stage 1 and 0.94 in stage 2) in certain subgroup patients in different scenarios. In conclusion, this study provided validated machine learning models and RF could provide a better accuracy in predicting the development of single uropathogen (E. coli) RUTI. Both host and bacterial characteristics made important contribution to the development of RUTI in the prediction models in the 2 clinical scenarios, respectively. Based on the results, physicians could take action to prevent the development of RUTI.

Theoretical study on the cross-linking reaction mechanism of cellulose nanofibrils initiated by fluorine.

Theoretical investigation on the cross-linking reaction process and mechanism of cellulose nanofibrils (CNFs) initiated by fluorine is accomplished by density functional theory. Three reaction pathways generated aldehyde and ester are identified. The reaction potential energy information of the ten reaction channels at B3LYP/6-311+G(d,p) level are obtained. The calculation results show that the reaction pathway of forming ester thereafter acyl fluoride has realized the cross-linking of cellulose. The reaction pathway of forming ester is more kinetically and thermodynamically favorable than the others of forming aldehyde with the lower energy barriers. The oxidation site mainly occurred at the methylene hydrogen of the hydroxymethyl group in the cellulose. The cross-linking of two cellulose molecules initiated by fluorine forming a covalent ester bond would be beneficial to improve cellulose mechanical properties of the insulating paper, which is better to add cellulose nanofibrils served as a "bridge" for strengthening the connection between celluloses.

Quantified Facial Rejuvenation Utilizing High Intense Focus Ultrasound with Multiple Penetrative Depths.

Background: Multiple penetration depths of high-intensity focused ultrasound (HIFU) treatment for facial rejuvenation have not been quantified. Methods: We enrolled 12 participants (n=24) to undergo one session of HIFU rejuvenation between January 1, 2019, and January 10, 2020. We used a 2-, 4.5-, and 6-mm focal depth transducer on the upper and middle face. We evaluated efficacy on days 60 and 90 by using our specific assessment system. Results: The average eyebrow peak and pupil-eyebrow peak angles significantly increased by 2° (p < 0.0005) and decreased by 1° (p < 0.0001), respectively, at day 90. The shortened eyebrow-iris length indicated that the forehead tissues had lifted and moved medially to the central face. Supraorbital tissues were also vertically elevated, marked by the eyebrow-orbital (p = 0.0016) and vertical palpebral fissure lengths (p = 0.0052), which both exhibited a 0.8-cm elevation. For the midface, the increased canthus-oral-nasal angle (p = 0.5881) and decreased tragus-oral length (p = 0.5881) indicated that laxity had been corrected through lifted oral commissure, though the data were not statistically significant. No serious side effects were observed. Conclusion: HIFU treatment with multiple depths quantitatively improved both upper-facial rejuvenation and midface rejuvenation after a single session.

Cephalometric analysis following combined Sub-SMAS hyaluronic acid injection and subdermal and supraperiosteal poly-L-lactic acid injections in Asian women.

BACKGROUND: The aging face is characterized by skin laxity and volume loss. Attenuation of facial retaining ligaments significantly contributes to skin sagginess and soft tissue volume loss. AIMS: We designed a prospective cohort study to quantitatively assess the efficacy of hyaluronic acid (HA) with adjunct poly-L-lactic acid (PLLA) injections in strengthening the retaining ligaments. PATIENTS/METHODS: A total of 12 Asian women were treated with HA injections to the orbital, zygomatic, buccal-maxillary, and mandibular retaining ligaments with adjunct supraperiosteal and subdermal PLLA injections to the temporal region, midface, and lower face. Cephalometric measurements were done before treatment and 2, 4, 12, and 24 weeks post-procedurally. RESULTS: Eyebrow peak and tail angles increased 20.0° ± 3.8° to 21.0° ± 3.8° (p < 0.05) and -2.9° ± 4.2° to -1.3° ± 3.3° (p < 0.001) at week 12. Eyebrow-to-orbital-rim distance increased 1.9 ± 2.0 mm to 3.9 ± 1.5 mm (p < 0.001) at week 12. Eyebrow-to-upper-eyelid distance increased 11.6 ± 3.0 mm to 12.7 ± 3.2 mm (p < 0.001) at week 24. Eyebrow-peak-to-lateral-limbus distance decreased 6.1 ± 3.1 mm to 5.3 ± 2.4 mm (p < 0.05) at week 4. Tragus-oral-commissure length and lower-facial-contouring length decreased 281 ± 11 mm to 275 ± 10 mm (p < 0.01) and 297 ± 14 to 292 ± 11 mm (p < 0.05) at week 12, respectively. CONCLUSION: Hyaluronic acid injection for strengthening of facial retaining ligaments with adjunct PLLA is viable, safe, and effective in facial rejuvenation as supported by quantitative data.

Shock Index as a Predictor for Angiographic Hemostasis in Life-Threatening Traumatic Oronasal Bleeding.

The objective of this retrospective study was to identify predictors of angiographic hemostasis among patients with life-threatening traumatic oronasal bleeding (ONB) and determine the threshold for timely referral or intervention. The diagnosis of traumatic, life-threatening ONB was made if the patient suffered from craniofacial trauma presenting at triage with unstable hemodynamics or required a definitive airway due to ONB, without other major bleeding identified. There were 4404 craniofacial trauma patients between January 2015 and December 2019, of which 72 (1.6%) fulfilled the diagnosis of traumatic life-threatening ONB. Of these patients, 39 (54.2%) received trans-arterial embolization (TAE), 11 (15.3%) were treated with other methods, and 22 (30.5%) were excluded. Motor vehicle accidents were the most common cause of life-threatening ONB (52%), and the internal maxillary artery was the most commonly identified hemorrhaging artery requiring embolization (84%). Shock index (SI) was significantly higher in the angiographic hemostasis group (p < 0.001). The AUC-ROC was 0.87 (95% CI, 0.88-1.00) for SI to predict angiographic hemostasis. Early recognition and timely intervention are crucial in post-traumatic, life-threatening ONB management. Patients initially presenting with SI > 0.95 were more likely to receive TAE, with the TAE group having statistically higher SI than the non-TAE group whilst receiving significantly more packed red blood cells. Hence, for patients presenting with life-threatening traumatic ONB and a SI > 0.95, TAE should be considered if preliminary attempts at hemostasis have failed.

Tension Stimulation of Tenocytes in Aligned Hyaluronic Acid/Platelet-Rich Plasma-Polycaprolactone Core-Sheath Nanofiber Membrane Scaffold for Tendon Tissue Engineering.

To recreate the in vivo niche for tendon tissue engineering in vitro, the characteristics of tendon tissue underlines the use of biochemical and biophysical cues during tenocyte culture. Herein, we prepare core-sheath nanofibers with polycaprolactone (PCL) sheath for mechanical support and hyaluronic acid (HA)/platelet-rich plasma (PRP) core for growth factor delivery. Three types of core-sheath nanofiber membrane scaffolds (CSNMS), consisting of random HA-PCL nanofibers (Random), random HA/PRP-PCL nanofibers (Random+) or aligned HA/PRP-PCL (Align+) nanofibers, were used to study response of rabbit tenocytes to biochemical (PRP) and biophysical (fiber alignment) stimulation. The core-sheath structures as well as other pertinent properties of CSNMS have been characterized, with Align+ showing the best mechanical properties. The unidirectional growth of tenocytes, as induced by aligned fiber topography, was confirmed from cell morphology and cytoskeleton expression. The combined effects of PRP and fiber alignment in Align+ CSNMS lead to enhanced cell proliferation rates, as well as upregulated gene expression and marker protein synthesis. Another biophysical cue on tenocytes was introduced by dynamic culture of tenocyte-seeded Align+ in a bioreactor with cyclic tension stimulation. Augmented by this biophysical beacon from mechanical loading, dynamic cell culture could shorten the time for tendon maturation in vitro, with improved cell proliferation rates and tenogenic phenotype maintenance, compared to static culture. Therefore, we successfully demonstrate how combined use of biochemical/topographical cues as well as mechanical stimulation could ameliorate cellular response of tenocytes in CSNMS, which can provide a functional in vitro environmental niche for tendon tissue engineering.

Functional Hyaluronic Acid-Polylactic Acid/Silver Nanoparticles Core-Sheath Nanofiber Membranes for Prevention of Post-Operative Tendon Adhesion.

In this study, we prepared core-sheath nanofiber membranes (CSNFMs) with silver nanoparticles (Ag NPs) embedding in the polylactic acid (PLA) nanofiber sheath and hyaluronic acid (HA) in the nanofiber core. The PLA/Ag NPs sheath provides mechanical support as well as anti-bacterial and anti-inflammatory properties. The controlled release of HA from the core could exert anti-adhesion effects to promote tendon sliding while reducing fibroblast attachment. From the microfibrous structural nature of CSNFMs, they function as barrier membranes to reduce fibroblast penetration without hampering nutrient transports to prevent post-operative peritendinous adhesion. As the anti-adhesion efficacy will depend on release rate of HA from the core as well as Ag NP from the sheath, we fabricated CSNFMs of comparable fiber diameter, but with thick (Tk) or thin (Tn) sheath. Similar CSNFMs with thick (Tk+) and thin (Tn+) sheath but with embedded Ag NPs in the sheath were also prepared. The physico-chemical properties of the barrier membranes were characterized in details, together with their biological response including cell penetration, cell attachment and proliferation, and cytotoxicity. Peritendinous anti-adhesion models in rabbits were used to test the efficacy of CSNFMs as anti-adhesion barriers, from gross observation, histology, and biomechanical tests. Overall, the CSNFM with thin-sheath and Ag NPs (Tn+) shows antibacterial activity with low cytotoxicity, prevents fibroblast penetration, and exerts the highest efficacy in reducing fibroblast attachment in vitro. From in vivo studies, the Tn+ membrane also shows significant improvement in preventing peritendinous adhesions as well as anti-inflammatory efficacy, compared with Tk and Tn CSNFMs and a commercial adhesion barrier film (SurgiWrap®) made from PLA.

Theoretical study on the grafting reaction of maleimide containing 2-hydroxy-benzophenone onto polyethylene.

A theoretical study on the multi-channel hydrogen addition of maleimide containing 2-hydroxy-benzophenone onto polyethylene in ultra-violet (UV) radiation cross-linking process was carried out using density functional theory (DFT) method at the B3LYP/6-311 + G(d,p) level. The energetic information and the minimum energy path (MEP) are calculated for nine reaction channels. The electrophilic addition reactions at two positions in the target molecule (maleimide containing 2-hydroxy-benzophenone) were investigated, which are on the C atom of C = C groups and on the O atom of C = O groups. Frontier molecular orbitals (MOs) and natural bond orbital (NBO) charge population of the target molecule have been analyzed in detail. As a result, the reaction site of C in C = C group is more active than the site of O in C = O groups. The target molecule can be used as a multi-functional additive candidate. The predicted mechanism may provide a theoretical basis for the real application of cross-linked polyethylene (XLPE) high-voltage insulation cables.

A Nanosensor for Naked-Eye Identification and Adsorption of Cadmium Ion Based on Core-Shell Magnetic Nanospheres.

Fe3O4@SiO2 nanospheres with a core-shell structure were synthesized and functionalized with bis(2-pyridylmethyl)amine (BPMA). The photoresponses of the as-obtained Fe3O4@SiO2-BPMA for Cr3+, Cd2+, Hg2+ and Pb2+ ions were evaluated through irradiation with a 352 nm ultraviolet lamp, and Fe3O4@SiO2-BPMA exhibited remarkable fluorescence enhancement toward the Cd2+ ion. The adsorption experiments revealed that Fe3O4@SiO2-BPMA had rapid and effective adsorption toward the Cd2+ ion. The adsorption reaction was mostly complete within 30 min, the adsorption efficiency reached 99.3%, and the saturated adsorption amount was 342.5 mg/g based on Langmuir linear fitting. Moreover, Fe3O4@SiO2-BPMA displayed superparamagnetic properties with the saturated magnetization of 20.1 emu/g, and its strong magnetic sensitivity made separation simple and feasible. Our efforts in this work provide a potential magnetic functionalized nanosensor for naked-eye identification and adsorption toward the Cd2+ ion.

Clinical Frailty Scale in Predicting Postoperative Outcomes in Older Patients Undergoing Curative Surgery for Urologic Malignancies: A Prospective Observational Cohort Study.

OBJECTIVE: To examine the utility of the Clinical Frailty Scale (CFS) in predicting outcomes in older adults with urologic malignancies undergoing curative surgeries. METHODS: This prospective observational cohort study was conducted in a university-based tertiary medical center. Patients aged 75 years or older who were scheduled to undergo curative surgery for a urologic malignancy from January 2017 to December 2017 were recruited. Patients were grouped according to the CFS scores. The primary postoperative outcome measures were a major complication within 30 days and a decline in the activities of daily living (ADL) within 30 days and 90 days. Multivariable analyses and the area under the receiver operating characteristic curve were performed to investigate the association between the CFS and postoperative outcomes. RESULTS: A total of 82 patients, 50% women, were enrolled with mean age 81.6 years. The CFS was significantly associated with postoperative outcomes in a dose-response relationship. When compared with those with a CFS <5, patients with CFS scores ≥5 had a 10.3-times higher risk for a major complication, 8.5-times and 21.4-times higher risk for a decline in ADL within 30 days and 90 days. The area under the receiver operating characteristic curves for the CFS to predict a major complication, the 30-day decline in ADL and the 90-day decline in ADL were 0.60, 0.73, and 0.79. CONCLUSION: A higher CFS score predicted a higher risk of poor outcomes in this population. It is recommended that patients with higher CFS scores, especially above 5, are needed to receive further multidisciplinary perioperative care.

Theoretical study on the hydrogen addition reactions to bismaleimide in the ultra-violet radiation cross-linking process of polyethylene.

Theoretical investigation on the multiple-channel addition reactions of hydrogen in polyethylene to bismaleimide in the Ultra-violet (UV) radiation cross-linking process is accomplished by density functional theory. Their energetic information of the nineteen reaction channels at B3LYP/6-311 + G(d,p) level is obtained. Two types of electrophilic addition reaction, one is the 4-position hydrogen in 4-methylheptane to C of C=C groups in bismaleimide and the other one is the 4-position hydrogen in 4-methylheptane to O of C=O groups in bismaleimide, are identified. The effects of introducing the heteroatom O and/or the benzene ring among both ends of the two maleimide rings have been evaluated. The results show that the addition reaction potential barrier height to O in C=O groups is lower than that of the C in C=C groups in the conjugative bismaleimide system.The founding of the addition reaction channel to O in C=O groups could clear further the mechanism of grafting bismaleimide to polyethylene.

Socioeconomic Inequality in One-Year Mortality of Elderly People with Hip Fracture in Taiwan.

Hip fracture commonly results in considerable consequences in terms of disability, mortality, long-term institutional care and cost. Taiwan launched its universal health insurance coverage in 1995, which largely removes financial barriers to health care. This study aims to investigate whether socioeconomic inequality in one-year mortality exists among Taiwanese elderly people. This population-based cohort study included 193,158 elderly patients (≥65 years) admitted for hip fracture between 2000 and 2012. With over a one-year follow-up, 10.52% of the participants died from all causes. The mortality rate was low in the northern part of Taiwan and in urban and high-family-income areas. Multiple Poisson regression models further suggested that the level of >Q1-Q3 and >Q3-Max showed significantly reduced odds ratio of one-year mortality at 0.90 (95% confidence interval (CI), 0.87-0.93) and 0.77 (95% CI, 0.74-0.81), respectively, compared with that of the lowest family income level (i.e., Min.-Q1). Despite a monotonic decline in overall one-year mortality during the study period, socioeconomic inequality in one-year mortality rate remained evident. The annual percentage change in one-year mortality was higher (-2.86) in elderly people from families with high income (>Q3-Max.) than that for elderly patients from family with low income (Min.-Q1, -1.94). Accessibility, rather than affordability, to health care for hip fracture is probably responsible for the observed socioeconomic inequality.

Hydrogel Film-Immobilized Lactobacillus brevis RK03 for γ-Aminobutyric Acid Production.

Hydrogels of 2-hydroxyethyl methacrylate/polyethylene glycol diacrylate (HEMA/PEGDA) have been extensively studied for their use in biomedical and pharmaceutical applications owing to their nontoxic and highly hydrophilic characteristics. Recently, cells immobilized by HEMA/PEGDA hydrogels have also been studied for enhanced production in fermentation. Hydrogel films of HEMA/PEGDA copolymer were generated by Ultraviolet (UV)-initiated photopolymerization. The hydrogel films were used to immobilize viable Lactobacillus brevis RK03 cells for the bioconversion of monosodium glutamate (MSG) to γ-aminobutyric acid (GABA). The mechanical properties and fermentation yields of the L. brevis RK03 cells immobilized on polyacrylate hydrogel films with different monomeric formulations were investigated. Fermentation was carried out in 75 mL de Man, Rogosa and Sharpe (MRS) medium containing various concentrations of MSG. We found that HEMA (93%)/PEGDA (3%) hydrogels (sample H) maximized GABA production. The conversion rate of MSG to GABA reached a maximum value of 98.4% after 240 h. Bioconversion activity gradually declined after 420 h to 83.8% after five cycles of semi-continuous fermentation. Our results suggest that HEMA (93%)/PEGDA (3%) hydrogels have great potential for use in GABA production via semi-continuous fermentation.