Optimization of isoprene production using a metabolically engineered Escherichia Coli

The volatile C5 hydrocarbon, isoprene is an important platform chemical, which has been used in the manufacture of synthetic rubber for tires and also has the potential for various other applications such as elastomers and adhesives. Moreover, isoprene is convertible to biofuel blend stocks such as C10 gasoline, C15 diesel, and jet fuels because of its higher energy content than other biofuels. Although isoprene is currently derived from petroleum, its sustainable supply has been suffered from price fluctuation of crude oil, high refining cost and energy consumption, and low recovery yield of pure isoprene. As an alternative, the biologically produced isoprene (bio-isoprene) has been developed rapidly for the last decade. Bio-isoprene is synthesized from dimethylallyl diphosphate (DMAPP), which is derived from mevalonate (MVA) pathway or the methylerythritol phosphate (MEP) pathway, by isoprene synthase. In this study, metabolic engineering for enhanced production of bio-isoprene was performed by deletion of relevant genes and optimization of culture condition. In comparison of isoprene production between E.coli DH5α and MG1655, lower isoprene production was observed in MG1655. The lower isoprene production in E. coli MG1655 was ascribed to the presence of recA gene which is absent in the DH5α strain. The deletion of recA gene in E.coli MG1655 allows higher isoprene production than E. coli DH5α. Moreover, the optimized expression of isoprene synthesis pathway with 0.03mM IPTG induction enhanced the isoprene production up to 2,850 mg/L. Overall, isoprene production through the optimization was improved by 28.5-fold compared to the initial production of MG1655 strain. Please click Additional Files below to see the full abstract

Effect of interlayer interactions on exciton luminescence in atomic-layered MoS2 crystals

The atomic-layered semiconducting materials of transition metal dichalcogenides are considered effective light sources with both potential applications in thin and flexible optoelectronics and novel functionalities. In spite of the great interest in optoelectronic properties of two-dimensional transition metal dichalcogenides, the excitonic properties still need to be addressed, specifically in terms of the interlayer interactions. Here, we report the distinct behavior of the A and B excitons in the presence of interlayer interactions of layered MoS 2 crystals. Micro-photoluminescence spectroscopic studies reveal that on the interlayer interactions in double layer MoS 2 crystals, the emission quantum yield of the A exciton is drastically changed, whereas that of the B exciton remains nearly constant for both single and double layer MoS 2 crystals. First-principles density functional theory calculations confirm that a significant charge redistribution occurs in the double layer MoS 2 due to the interlayer interactions producing a local electric field at the interfacial region. Analogous to the quantum-confined Stark effect, we suggest that the distinct behavior of the A and B excitons can be explained by a simplified band-bending model.1

Synchronous granular cell tumors in the perianus and chest wall

Granular cell tumor (GCT) is a rare tumor that originates from the Schwann cells in the skin, soft tissues, and internal organs. Usually, GCTs are clinically benign, although malignant and multifocal forms are very rarely known to occur. Cases of GCT of the perianus are rare, and thus far, no study has reported synchronous GCTs of the perianus and the chest wall. We report a case of a 31-year-old woman with synchronous GCTs of the perianus and the chest wall to have a mind of consideration of the possibility of GCT in the differential diagnosis of perianal tumor

Clinical Outcomes and Prognostic Factors of Up-Front Autologous Stem Cell Transplantation in Patients with Extranodal Natural Killer/T Cell Lymphoma

AbstractLimited data exist on up-front autologous stem cell transplantation (ASCT) in extranodal natural killer/T cell lymphoma (ENKTL). Sixty-two patients (43 men and 19 women) with newly diagnosed ENKTL who underwent up-front ASCT after primary therapy were identified. Poor-risk characteristics included advanced stage (50%), high-intermediate to high-risk International Prognostic Index (25.8%), and group 3 to 4 of NK/T Cell Lymphoma Prognostic Index (NKPI, 67.7%). Pretransplant responses included complete remission in 61.3% and partial remission in 38.7% of patients, and final post-transplantation response included complete remission in 78.3%. Early progression occurred in 12.9%. At a median follow-up of 43.3 months (range, 3.7 to 114.6), 3-year progression-free survival (PFS) was 52.4% and 3-year overall survival (OS) was 60.0%. Patients with limited disease had significantly better 3-year PFS (64.5% versus 40.1%, P = .017) and OS (67.6% versus 52.3%, P = .048) than those with advanced disease. Multivariate analysis showed NKPI and pretransplant response were independent prognostic factors influencing survival, particularly NKPI in limited disease and pretransplant response in advanced disease. Radiotherapy was an independent factor for reduced progression and survival in patients with limited disease, but anthracycline-based chemotherapy was a poor prognostic factor for progression in patients with advanced disease. Up-front ASCT is an active treatment in ENKTL patients responding to primary therapy

Comparative Genomic Analysis of the 2016 Vibrio cholerae Outbreak in South Korea

In August 2016, South Korea experienced a cholera outbreak that caused acute watery diarrhea in three patients. This outbreak was the first time in 15 years that an outbreak was not linked to an overseas source. To identify the cause and to study the epidemiological implications of this outbreak, we sequenced the whole genome of Vibrio cholerae isolates; three from each patient and one from a seawater sample. Herein we present comparative genomic data which reveals that the genome sequences of these four isolates are very similar. Interestingly, these isolates form a monophyletic Glade with V. cholerae strains that caused an outbreak in the Philippines in 2011. The V. cholerae strains responsible for the Korean and Philippines outbreaks have almost identical genomes in which two unique genomic islands are shared, and they both lack SXT elements. Furthermore, we confirm that seawater is the likely source of this outbreak, which suggests the necessity for future routine surveillance of South Korea's seashore.

Ketamine use for endotracheal intubation in severe sepsis and septic shock

Objective. We conducted this study to evaluate the clinical outcomes of patients with severe sepsis and septic shock who were treated with ketamine for endotracheal intubation. Methods. A single-center, retrospective study was carried out to compare the outcomes of patients with severe sepsis and septic shock who received a ketamine or non-ketamine agent for rapid sequence intubation (RSI). We analyzed the sepsis registry for adult patients who presented to the emergency department (ED), met the criteria for severe sepsis or septic shock, and underwent endotracheal intubation between August 2008 and March 2014. Te primary outcome was 28-day mortality. We performed a multivariable logistic regression analysis to assess the association between ketamine use for intubation and 28-day mortality. Results. In all, 170 patients were intubated during the study period. Of the eligible patients, 95 received ketamine and 75 received a non-ketamine agent. Te 28-day mortality of the ketamine group was not signifcantly diferent from that of the nonketamine group (38% vs. 40%, respectively,P=0.78). Te unadjusted odds ratio (OR) of ketamine use for 28-day mortality was 0.92 (95% CI: 0.49–1.70, P=0.78). Te association remained insignifcant afer adjusting for age, gender, malignancy, initial lactate level on ED admission, time to frst antibiotic administration, Acute Physiology and Chronic Health Evaluation II score on admission day, and propensity score regarding ketamine use (adjusted OR: 1.09; 95% confdence interval [CI]: 0.49–2.40;P=0.84). Initial serum lactate on ED admission was the only signifcant predictive factor of 28-day mortality (adjusted OR: 1.23; 95% CI: 1.10–1.38; P<0.01). Conclusions. For patients with severe sepsis and septic shock who were intubated using RSI, we found no signifcant diference in 28-day mortality between those who received ketamine as a sedative agent and those who received alternative sedatives

Improved cortical activity and reduced gait asymmetry during poststroke self-paced walking rehabilitation

Background For patients with gait impairment due to neurological disorders, body weight-supported treadmill training (BWSTT) has been widely used for gait rehabilitation. On a conventional (passive) treadmill that runs at a constant speed, however, the level of patient engagement and cortical activity decreased compared with gait training on the ground. To increase the level of cognitive engagement and brain activity during gait rehabilitation, a self-paced (active) treadmill is introduced to allow patients to actively control walking speed, as with overground walking. Methods To validate the effects of self-paced treadmill walking on cortical activities, this paper presents a clinical test with stroke survivors. We hypothesized that cortical activities on the affected side of the brain would also increase during active walking because patients have to match the target walking speed with the affected lower limbs. Thus, asymmetric gait patterns such as limping or hobbling might also decrease during active walking. Results Although the clinical test was conducted in a short period, the patients showed higher cognitive engagement, improved brain activities assessed by electroencephalography (EEG), and decreased gait asymmetry with the self-paced treadmill. As expected, increases in the spectral power of the low γ and β bands in the prefrontal cortex (PFC), premotor cortex (PMC), and supramarginal gyrus (SG) were found, which are possibly related to processing sensory data and planning voluntary movements. In addition, these changes in cortical activities were also found with the affected lower limbs during the swing phase. Since our treadmill controller tracked the swing speed of the leg to control walking speed, such results imply that subjects made substantial effort to control their affected legs in the swing phase to match the target walking speed. Conclusions The patients also showed reduced gait asymmetry patterns. Based on the results, the self-paced gait training system has the potential to train the symmetric gait and to promote the related cortical activities after stroke. Trial registration Not applicableThis work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIT) (No. NRF-2020R1A2C2012641). This study has also been supported by Grant numbers (16-2016-003, 16-2017004) from the SNUBH-KAIST Collaboration Research Fund

Current Situation and Issue of Industrial Accident Compensation Insurance

Industrial Accident Compensation Insurance (IACI) has a history of about 50 yr, and is the oldest social insurance system in Korea. After more than 20 times of revision improvements in benefits, its contents and claim systems have been upgraded. It became the protector of injured workers and their families, and at the same time became the system which could cope with both financial burden of employers and their responsibilities. However, there are some issues to be reformed to upgrade the IACI: 1) the problems in the approval system of occupational diseases, 2) quality improvement of workers' compensation medical care, 3) vocational rehabilitation and return to work, 4) workers' compensation premiums and out-of-pocket money of injured workers, 5) issues in application of IACI. Growth of IACI cannot be achieved by an effort of an individual. Efforts by workers, owners, and government, in addition to physicians and welfare professionals toward the same goal are required for the next level improvement of IACI