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Retrospective cohort study OBJECTIVE: To investigate the long-term effects of bone cement-augmented instrumentation in multilevel lumbar fusions SUMMARY OF BACKGROUND DATA: Cement-augmented screw is one of the techniques used to reduce early mechanical failure in multilevel lumbar fusion, especially in the elderly. However, there is little information regarding the long-term effects.Fifty one patients who underwent three or more levels of lumbar fusion were divided into two groups according to bone cement-augmented screw fixation involving the upper instrumented vertebra (UIV): 22 patients (cemented group, group I) and 29 patients (non-cemented group, group II). The analysis of radiographic adjacent segment degeneration (ASD) involved patients with lumbosacral fusion showing a similar degree of osteoporosis. Radiologic ASD was defined as more than two UCLA grades of progression at 2 years postoperatively. Other sagittal parameters were analyzed and preoperative MR Pfirrmann grades for adjacent level, probably related to ASD.Even when no significant differences existed in preoperative demographic and radiographic parameters between the two groups, the postoperative kyphotic changes at 3 months were higher in the non-cemented group. In terms of long-term effects, radiologic ASD (20 patients (95.2%) in group I; 15 (53.6%) in group II) was significantly higher in the cemented group. Logistic regression analysis of radiologic ASD including other clinical and radiological parameters, postoperative PI-LL mismatch (OR 5.201, 95% CI 1.123-24.090, p = 0.035) and cement augmentation (OR 20.193, 95% CI 2.195-185.729, p = 0.008) showed a significant correlation with the development of radiologic ASD at postoperative 2 years.Although bone cement-augmented screw implantation can prevent kyphotic deformation at the proximal junction of UIV in early postoperative stages of multi-level lumbar fusion, a discreet selection of patients is required due to possible accelerated degeneration of adjacent segments.

Objective This study was aimed to compare the oncologic outcomes of patients with non-endometrioid endometrial cancer who underwent minimally invasive surgery with the outcomes of patients who underwent open surgery. Method This is a retrospective, multi-institutional study of patients with non-endometrioid endometrial cancer who were surgically staged by either minimally invasive surgery or open surgery. Oncologic outcomes of the patients were compared according to surgical approach. Results 113 patients met the inclusion and exclusion criteria. 57 underwent minimally invasive surgery and 56 underwent open surgery. Patients who underwent minimally invasive surgery had smaller tumors (median size, 3.3 vs. 5.2%, p = 0.0001) and a lower lymphovascular space invasion rate (29.8% vs. 48.2%, p = 0.045). In the overall population, the numbers and rate of recurrence were significantly higher in the open surgery group (p = 0.016). In multivariate analysis, disease stage and tumor size were associated with DFS in contrast to surgical procedure. Conclusion Minimally invasive surgery showed similar survival outcomes when compared to open surgery in non-endometrioid endometrial cancer patients, irrespective of disease stage. When minimally invasive surgery is managed by expert surgeons, non-endometrioid histological subtypes should not be considered a contraindication for minimally invasive surgery.

Herein, we investigated the influence of sulfur (S) addition on the phase formation behavior and thermoelectric transport properties of n-type Cu0.008Bi2Te3. A complete single phase of rhombohedral Bi2Te3 was formed in Cu0.008Bi2Te2.8S0.2, whereas a mixture of Bi2Te3 and Bi2Te2S1 phases was generated at higher S contents. We elucidated the complex effects of S substitution at Te-site on transport properties of Cu0.008Bi2Te3; (1) increase in density-of-states effective mass, (2) decrease in weighted mobility ratio, (3) reduction in lattice thermal conductivity, and (4) reduction in bipolar thermal conductivity. Despite the slight deterioration in electronic transport properties, a maximum thermoelectric figure of merit (zT) of 0.82 was achieved at 400 K in Cu0.008Bi2Te2.8S0.2 due to the synergetic effect of intensified point defect phonon scattering in a wide temperature range and suppressed bipolar thermal conduction at elevated temperatures.

Three-dimensional flower-like tungsten oxide nanoplates sequentially doped with Co at different concentrations were fabricated using a single solvothermal process. The response of the nanostructure of the n-type tungsten oxide used for sensing ethanol gas, which is a reducing gas, changed sequentially according to the process temperature and doping concentration of Co. This response cannot be attributed to a single reason, but it can be regarded as a result of the combination of several complicated direct and indirect phenomena such as (1) point, line, and cross-section defects on the surface, (2) change in initial resistance corresponding to doping concentration, (3) catalytic effect of dopant, and (4) difference in energy level at heterojunctions. Therefore, unlike in the case of other gas sensing methods that depend on a main cause or mechanism, it might be meaningful in the case of ethanol gas sensing to analyse each cause and predict the results of different combinations.

Objective We investigated the characteristics and revision rate of junctional failure after surgical correction for thoracolumbar kyphosis in patients with ankylosing spondylitis. Methods A total of 230 patients had undergone surgical correction for thoracolumbar kyphosis from 2010 to 2019. The state of ankylosis between the uppermost instrumented vertebra (UIV) and UIV+1 and between the lowermost instrumented vertebra (LIV) and LIV−1 was analyzed using a modified Stoke ankylosing spondylitis spine score. Proximal junctional failure (PJF) and distal junctional failure (DJF) were defined as any type of symptomatic junctional failure. Results Of the 230 patients, 23 (10.0%) had developed junctional failure. Of these 23 patients, 16 had had partial ankylosis and 7 had had complete ankylosis. PJF had developed in 10 patients and DJF in 13. The most common type of junctional failure was a junctional fracture, which developed in 12 patients. PJF had developed by UIV fracture in 4 patients, UIV+1 fracture in 1 patient, and UIV+2 in 1 patient. DJF had developed by LIV fracture in 6 patients, metallic failure in 5, and progression of DJF in 2 patients. The average time to the development of PJF and DJF was 13 months and 12.4 months, respectively. All 10 patients with PJF and 7 of 13 patients with DJF (53.8%) had required reoperation. Of the 12 patients with junctional fracture, 11 (91.7%) had undergone reoperation. Conclusions Of the 23 patients with junctional failure, 16 had had immature ossification of the anterior longitudinal ligament. Therefore, to prevent junctional failure, the state of ankylosis seems to be important for selecting the fusion level after osteotomy. Once junctional failure has developed, however, reoperation should be considered owing to the stress concentration at the UIV or LIV.

The urchin-like nanoparticles of semiconducting oxides have been attracting considerable attention as they can significantly improve reactivity owing to their enlarged surface areas. Herein, we report a simple and scalable synthesis method of ZnO nanomaterials via a microwave-assisted drying process. Commercial ZnO powders (~300 nm) and expanded graphite were used as starting materials to prepare urchin-like ZnO nanoparticles with nanoscale legs (diameter ~20 nm) by triggering the rapid phase transformation, which was induced by a repeated microwave irradiation in an alumina crucible for a few minutes. The possible mechanisms to trigger this morphological and dimensional change are described in detail. The high-yield production and superior reproducibility completed in shortened processing times enable this synthetic route to be widely applicable for the massive production of nanostructured oxide particles.

Mitochondrial genomes of the three lucanid species in the Dorcus velutinus complex – Dorcus velutinus Thomson, D. ursulus Arrow and D. tenuihirsutus Kim and Kim – were assembled and analyzed through next generation sequencing. The mitogenome sequences were used to infer phylogenetic relationships among Dorcus species. Our analyses revealed that the newly sequenced mitogenomes are comparable in their size, content, and gene arrangement to other lucanid mitogenomes reported to date. However, we confirmed the presence of a large intergenic spacer (IGS) between trnS(UCN) and ND1 genes, whose length varied from 170 bp (in D. tenuihirsutus) to 193 bp (in D. ursulus and D. velutinus). Within this IGS region, a short sequence fragment (TACTAAATT) was found uniquely across the three species of Dorcus velutinus complex. Our phylogenetic analyses show that the D. velutinus complex constitutes a distinct clade with a significant divergence from other species of the genus Dorcus sensu stricto. Furthermore, we reaffirm the validity of D. tenuihirsutus – a species originally described from Korea – as a distinct species, though the taxonomic status of D. ursulus remains to be studied further. Finally, we find the presence and location of large IGSs to be useful for studying evolutionary history and species delimitation in stag beetles.

The addition of Cu becomes essential in polycrystalline n-type Bi2(Te,Se)3-based alloys since it is known to enhance stability of carrier transport properties as well as thermoelectric performance. However, a way to further optimize is necessary owing to the limited controllability of transport parameters by Cu addition. Herein, we present improved carrier transport properties via I-doping in Cu0.008Bi2Te2.7Se0.3. Weighted mobility and effective mass are increased simultaneously by small amount doping of I at Te/Se-site. As a result, ~15% increased power factor and high average thermoelectric figure of merit (zT) of 0.79 were obtained in a wide temperature range.

Cu doping has been known to enhance thermoelectric performance of p-type (Bi,Sb)2Te3 alloys by suppressing bipolar conduction at higher temperatures. However, detailed mechanisms are not provided yet. Herein, we investigate the unchallenged role of Cu doping in (Bi,Sb)2Te3 alloys by means of Bi-rich compositions of Bi0.6Sb1.4Te3 and Bi0.7Sb1.3Te3, which were chosen since they exhibit much inferior thermoelectric performance owing to severe bipolar conduction. It was found that Cu doping increases non-degenerate mobility and density-of-states effective mass of valence band as well as hole concentration. Small amount of Cu doping enhanced maximum thermoelectric figure-of-merit of Bi0.6Sb1.4Te3 composition from 0.25 to 0.98.

Nanoparticles in thermoelectric alloys has been considered as one of the most important ingredients to enhance their thermoelectric figure of merit zT mainly by reducing the lattice thermal conductivity due to intensified phonon scattering. However, the scattering mechanism of phonon with respect to wavelengths, which provides the comprehensive design rules for nanocomposites with enhanced zT, has not been fully understood. Here, we report a critical role of nanoparticles for the lattice thermal conductivity reduction from the theoretical and experimental analysis of the temperature-dependent thermal and electronic transport properties of p-type Ag/Cu nanoparticles-embedded Bi0.5Sb1.5Te3 with respect to their electronic, bipolar, and lattice thermal conductivities. It was found that the introduction of the Ag/Cu nanoparticles reduced the lattice thermal conductivity through the additional phonon scattering based on the changeover between the Rayleigh and geometrical scatterings, indicating the indispensability of nanoparticles to scatter phonons that cannot be scattered effectively by either point defects or grain boundaries.

Atomic-scale defects are essential for improving thermoelectric (TE) performance of most state-of-the-art materials by simultaneously tuning the electronic and thermal properties. However, because the plural atomic-scale defects are generally inherent and disordered in nanostructured TE materials, their complexity and ambiguity on determining TE performance remain a challenge to be solved. Furthermore, the thermal stability of atomic-scale defects in nanostructured TE materials has not been studied much so far. Herein, we report that the atomic-scale defect disorders are indispensable for high TE performance of nanostructured Ti1–xHfxNiSn1–ySby half-Heusler alloys, but gradually degraded at over 773 K, deteriorating the TE performance. It is found from the thermal annealing of nanostructured Ti0.5Hf0.5NiSn0.98Sb0.02 alloys that the annihilation of Ti,Hf/Sn antisite defects primarily reduces atomic-scale defect disorders and largely contributes to the increase of lattice thermal conductivity. Moreover, it is verified that the Ni interstitial defects mainly dominate the electronic transport properties, leading to the enhancement of power factor. Direct atomic structure observations clearly demonstrate the inherent Ni interstitial defects and the thermal vulnerability of Ti,Hf/Sn antisite defects. These results provide an important guide for the application of half-Heusler alloys with highly disordered atomic-scale defects.

Background Enterococcus species are a common cause of bacteremia in liver transplant recipients. Vancomycin-resistant enterococci (VRE) have become an important cause of nosocomial infection. In this study, we analyzed the incidence, antibiotic resistance, and outcomes of enterococcal bacteremia in living donor liver transplant recipients and the risk factors for VRE. Patients and Methods This single-center, retrospective review included 536 patients who underwent liver transplant between January 2008 and December 2017. Results Among 536 patients, 42 (7.8%) experienced a total of 58 enterococcal bacteremic episodes (37 Enterococcus faecium, 17 Enterococcus faecalis, 2 Enterococcus casseliflavus, 1 Enterococcus. avium, and 1 Enterococcus raffinosus). Most cases of enterococcal bacteremia (46/58, 79.3%) occurred within 6 months after transplant; among the 26 cases of VRE bacteremia, 50% occurred within 1 month after transplant. E. faecium isolates had the highest rate of vancomycin resistance (25/37, 67.5%), whereas all E. faecalis isolates were susceptible to vancomycin. According to multivariate analysis, post-transplant dialysis (odds ratio, 3.95; 95% CI, 1.51–10.34; P = .005) and length of post-transplant hospital stay (odds ratio, 1.03; 95% CI, 1.009–1.04; P = .004) were significantly associated with VRE bacteremia. One-year mortality was 31% (13/42) among recipients with enterococcal bacteremia, 5.0% (20/384) among nonbacteremic patients, and 11.1% (10/90) among patients with nonenterococcal bacteremia (P Conclusion In this study, enterococcal bacteremia showed high incidence in liver transplant recipients, especially with vancomycin resistance, occurred in early period after transplant, and was associated with increased mortality. High rates of resistance to vancomycin warrant further efforts to manage enterococcal infection in liver transplant recipients at our center.

In this paper, a novel frequency synchronization method is proposed for fast connection the islanded microgrid to the existing grid. In the conventional frequency synchronization method, the output of the synchronization controller is limited to maintain the voltage quality of the islanded microgrid. Due to this limitation of the output, the micro grid voltage has a nonlinear characteristic during the synchronization process. Conventional methods that do not consider the nonlinear characteristic have a drawback in that the synchronization speed can be slowed depending on the convergence direction of the frequency. To overcome the drawback, the nonlinear characteristic of the conventional method is analysed during the synchronization process. Based on the analysis, the synchronization speed is predicted according to the synchronization direction of the microgrid voltage. Using this prediction, a novel synchronization technique that finds a relatively fast synchronization direction is proposed. A 2MVA microgrid system is constructed using a real-time hardware-in-loop system and experimental results are presented to verify the validity of the proposed method. From experimental results, it is confirmed that the proposed method guarantees a faster synchronization speed than the conventional method.

To analyze the effects of direct vertebral rotation (DVR) on radiologic outcomes in the treatment of thoracic adolescent idiopathic scoliosis after selective thoracic fusion with pedicle screw instrumentation.Adolescent idiopathic scoliosis patients with single thoracic curves (n = 110) treated by selective thoracic fusion with a minimum of 2 years of follow-up were retrospectively analyzed. The patients were separated into 2 groups: non-DVR (n = 63) and DVR (n = 47).There was a significant difference in fused segments between the non-DVR and DVR groups (P0.001). There was also a significant difference in main thoracic curve postoperatively (P = 0.001) and at the last follow-up (P = 0.006) between the non-DVR and DVR groups. However, there was no significant difference in proximal thoracic and lumbar curves postoperatively (proximal thoracic curve: P = 0.186; lumbar curve: P = 0.155) and at the last follow-up (proximal thoracic curve: P = 0.250; lumbar curve: P = 0.060) between the 2 groups. Significant improvements in the lowest instrumented vertebra tilt and disc angle were noted but then slight deteriorations in such were observed during the follow-up period in the non-DVR group. The prevalence of unsatisfactory results was 20.6% (13 of 63) in the non-DVR group and 19.1% (9 of 47) in the DVR group, with no significant difference (P = 0.522).For correcting single thoracic adolescent idiopathic scoliosis by selective thoracic fusion with pedicle screw instrumentation, the addition of DVR to the surgical procedure showed comparable radiologic outcomes compared with non-DVR procedures.

Background As the prevalence of spinal fusion surgery has increased, reliable and safe bone graft substitutes have been developed in response. Biocompatible osteoconductive polymer (BOP) has been used as a bone graft alternative for spine surgery. We present a case of cervical myelopathy due to extrusion of BOP 23 years after surgery and discuss the pathophysiology in terms of spinal fusion. Case Description A 65-year-old man presented with a 3-month history of cervical myelopathic symptoms. Twenty-three years earlier, the patient had undergone cervical surgery for a C6–7 herniated disc with the use of BOP. Imaging studies of the cervical spine showed cord compression due to extruded BOP at C6–7. He underwent corpectomy of the C7 vertebral body and removal of the BOP for the neural decompression, combined with interbody fusion by use of an iliac bone graft and plate fixation. During the operation, crumbly fibers of the BOP were easily removed. His myelopathic symptoms improved immediately after surgery. Postoperative magnetic resonance imaging also showed successful decompression of the spinal cord. Histologically, a foreign body reaction and bony degeneration were found around the synthetic fibers of the BOP. Conclusions Spine surgeons should recognize the pathophysiology of the BOP used for spine fusion surgery. Although BOP is not currently used for spinal surgery, patients undergoing previous surgery with the BOP can present with related complications. Revision surgery is recommended to remove the unincorporated BOP and achieve solid spine fusion.

Herein, we report the enhanced thermoelectric performance of Cu incorporated Bi2Te2.7Se0.3 prepared by melt spinning. The electronic transport properties were significantly improved by Cu incorporation due to the synergetic effect of carrier tuning, band modification, and electron-phonon transport control. The steady dimensionless thermoelectric figure of merit higher than 0.90 was achieved in the wide range of temperature range of 350–450 K for Cu0.008Bi2Te2.7Se0.3, which is ~30% enhancement in comparison with pristine Bi2Te2.7Se0.3. This result can lead to high thermoelectric power generation efficiency 4.2% at ΔT = 180 K.

The thermoelectric transport properties of artificially textured polycrystalline CrSiTe3 samples have been investigated for elucidating their correlations with a crystal structure and the corresponding charge density distribution. We verified that the low mobility of 13–27 cm2 V−1 s−1 attributing poor electronic transport properties is originated from the discrete charge density distribution in the covalently bonded layer. Also, the modulation of thermal conductivity values from 3.5 to 5.4 W m−1 K−1 with varying the texture was confirmed in pristine CrSiTe3. Thus, we suggest that the electronic and thermal transport properties of layer structured CrSiTe3 are strongly correlated with crystallographic features.

We report a facile and efficient way to enhance and modulate thermoelectric performance by incorporating chemically synthesized Cu2Te nanoparticles on p-type Bi0.5Sb1.5Te3 matrix. By varying the amount of Cu2Te nanoparticles, the temperature of maximum thermoelectric performance shifted systematically from room temperature to 425 K. The highest figure-of-merit value, 1.1, was achieved at 377 K by incorporating 0.1 wt% Cu2Te nanoparticles in Bi0.5Sb1.5Te3 matrix, which is due to enhancement in power factor and reduction in lattice thermal conductivity. The results demonstrate that Cu2Te incorporation could be an effective strategy for Bi-Te based thermoelectric power generation.

Controlling electronic and thermal transport properties simultaneously is an ultimate strategy to accomplish high-performance thermoelectrics. Here, our analysis on carrier transport of a nanograined p-type Bi0.5Sb1.5Te3 thermoelectric alloy clearly reveals that reducing grain size greatly suppresses bipolar conduction by selective suppression of minority carrier (electron) mobility, resulting in both the power factor enhancement and bipolar thermal conductivity reduction. Furthermore, it is shown how reducing grain size affects decreasing lattice thermal conductivity in respect to grain size and phonon wavelength. Therefore, minimizing grain size can enhance thermoelectric performance of Bi0.5Sb1.5Te3 alloy by controlling both electronic and thermal transport properties synergetically.

The feasibility of using Bi2Te3-based alloys in low-grade heat thermoelectric power generation has been intensively investigated via a substitutional doping approach over the last decade. However, the comprehensive and quantitative understanding of the electronic and thermal transport parameters of doped Bi2Te3-based alloys including their carrier concentration (nc), carrier mobility (μHall), density of state (DOS) effective mass (md∗), and electronic (κele), lattice (κlat), and bipolar thermal (κbp) conductivities is still elusive. The understanding of these parameters is a prerequisite for designing the modules for real-time applications. In this study, we investigated the effect of Pb, Ag, and Cu doping on the thermoelectric transport parameters of p-type Bi0.52Sb1.48Te3 (BST) both theoretically and experimentally. The thermoelectric transport properties of BST and their temperature dependences could be systematically tuned in a low-temperature range by controlled doping of Pb, Ag, and Cu mainly because of the increased concentration of the majority hole carriers. In addition, a zT value of 1 could be obtained over the wide temperature range of 300–400 K by optimizing the doping elements and contents because of the synergetic effect of the suppression of bipolar conduction at higher temperatures and the gradual increase in md∗ with the doping content at nc

Cation substitutional doping has been shown to be an effective method to modify both the electronic and thermal transport in p-type (Bi,Sb)2Te3-based thermoelectric alloys. However, there are not many studies that have attempted a quantitative analysis on the influence of cation substitution on the electronic and thermal properties of n-type Bi2(Te,Se)3-based alloys. In this work, we report a comprehensive analysis of the influence of substitutional Nb doping on the electrical and thermal conductivity in n-type Cu0.008Bi2Te2.7Se0.3 alloys. First, we found that Nb doping increases the carrier concentration of both the electrons and holes, whereas the weighted mobility of the electrons and holes is only slightly modified based on a single parabolic band model. As a result, the bipolar thermal conductivity was increased as the Nb was doped. Next, the contribution of point defect scattering by the Nb substitution on the thermal conductivity of the lattice was quantitatively analyzed using a Debye-Callaway model, and it was concluded that the influence of cation substitutional doping in n-type Bi2(Te,Se)3 is as effective as that in p-type (Bi,Sb)2Te3.

Bi-Te based materials have been used for near-room-temperature thermoelectric applications. However, their properties dramatically decrease at high temperatures (over 100 °C), limiting their use in power generation. In this study, we investigated the enhanced thermoelectric properties of Bi-Te based materials by Cu doping and employing the melt-spinning (MS) process that can be utilized especially at elevated temperatures. By changing the doping amount, we could modulate the temperature dependence of thermoelectric properties, where the maximum ZT temperature could be shifted from room temperature to 450 K. The highest ZT value, 1.34, was achieved at 400 K for 2% Cu-doped Bi0.5Sb1.5Te3, which is due to the enhancement in power factor and reduction in lattice thermal conductivity. The average ZT value between room temperature and 530 K was 1.17 for 2% Cu-doped Bi0.5Sb1.5Te3, which is 46% higher than that of pristine Bi0.5Sb1.5Te3. Consequently, the synergetic effect of MS process and Cu incorporation can be a promising method to widen the application of Bi-Te based thermoelectric materials for mid-temperature power generation.

The longhorn beetle genus Callipogon Audinet-Serville represents a small group of large wood-boring beetles whose distribution pattern exhibits a unique trans-Pacific disjunction between the East Asian temperate rainforest and the tropical rainforest of the Neotropics. To understand the biogeographic history underlying this circum-Pacific disjunct distribution, we reconstructed a molecular phylogeny of the subfamily Prioninae with extensive sampling of Callipogon using multilocus sequence data of 99 prionine and four parandrine samples (ingroups), together with two distant outgroup species. Our sampling of Callipogon includes 18 of the 24 currently accepted species, with complete representation of all species in our focal subgenera. Our phylogenetic analyses confirmed the purported affinity between the Palearctic Callipogon relictus and its Neotropical congeners. Furthermore, based on molecular dating under the fossilized birth-death (FBD) model with comprehensive fossil records and probabilistic ancestral range reconstructions, we estimated the crown group Callipogon to have originated in the Paleocene circa 60 million years ago (Ma) across the Neotropics and Eastern Palearctics. The divergence between the Palearctic C. relictus and its Neotropical congeners is explained as the result of a vicariance event following the demise of boreotropical forest across Beringia at the Eocene-Oligocene boundary. As C. relictus represents the unique relictual species that evidentiates the lineage's expansive ancient distribution, we evaluated its conservation importance through species distribution modelling. Though we estimated a range expansion for C. relictus by 2050, we emphasize a careful implementation of conservation programs towards the protection of primary forest across its current habitats, as the species remains highly vulnerable to habitat disturbance.

Background Acinetobacter baumannii has become an increasingly important nosocomial pathogen. Carbapenem is the preferred drug of choice for treatment of multidrug-resistant gram-negative bacilli, but carbapenem-resistant A baumannii (CRAB) has now emerged. The aim of this study was to determine the incidence, outcomes, and risk factors for CRAB bacteremia in liver transplant recipients. Methods The medical records of 393 subjects who underwent living donor liver transplant at Seoul St. Mary's Hospital from January 2008 to April 2015 were reviewed. Results A total of 92 (23.4%) bacteremic patients, comprising 156 episodes, were identified. Fourteen patients, totaling 18 episodes, had CRAB bacteremia. The median time of emergence of CRAB bacteremia was 55.5 (range, 2–829) days after transplantation, and 72.2% of episodes (n = 13) occurred within 6 months of transplant. The presumed sources of infection were intra-abdominal (n = 11, 61.1%), biliary tract (n = 3, 16.7%), lung (n = 2, 11.1%), catheter (n = 1, 5.6%), and wound (n = 1, 5.6%). By multivariate analysis, length of post-transplant intensive care unit (ICU) stay (odds ratio [OR], 1.1, 95% confidence interval [CI], 1.11–1.15; P = .04) was associated with CRAB bacteremia. Overall mortality in 14 recipients with CRAB bacteremia was 50% (n = 7), but only 10% (30 of 301) in non-bacteremic patients and 20.5% (16 of 78) in other bacteremic patients excluding CRAB (P Conclusion In our study, patients with CRAB bacteremia after liver transplant showed an unfavorable outcome and, recently, CRAB has become an increasingly major pathogen at our center. Reducing the length of ICU stay could be a solution for preventing CRAB bacteremia.

Substitutional doping is known to be effective when used to enhance the thermoelectric figure of merit zT, and this is generally explained as resulting from a reduction in the thermal conductivity caused by an additional atomic-scale defect structure. However, a comprehensive analysis of the substitutional doping effect on the electrical and thermal properties together has not been undertaken, especially when the bipolar thermal conductivity becomes serious. A previous study by the authors also showed that the zT of Bi0.4Sb1.6Te3 thermoelectric alloys was enhanced by indium (In) doping due to the reduction of the total thermal conductivity. Here, we more closely analyze the electrical and thermal transport properties of a series of indium (In)-doped p-type Bi0.4Sb1.6-xInxTe3 (x = 0, 0.003, 0.005, 0.01) using both the single-parabolic-band model and the Debye-Callaway model in an effort to investigate the origin of the observed thermal conductivity reduction more closely. The bipolar contribution to the total thermal conductivity was estimated exclusively based on a two-band model based on a single-parabolic-band model. Furthermore, the lattice thermal conductivity was calculated using the Debye-Callaway model while taking additional In substitutional defects into consideration. The calculations indicated that the significant suppression of bipolar thermal conductivity was achieved as a result of the increased bandgap in Bi0.4Sb1.6Te3 caused by In doping. Additional point defects from In doping also reduced the lattice thermal conductivity, but not as much as the bipolar thermal conductivity did. The study suggests that the suppression of bipolar conduction by means of a bandgap modification can be an effective approach for enhancing zT further via a simple In-doping process in Bi0.4Sb1.6Te3.

Thoracic ossification of the ligamentum flavum (TOLF) is an uncommon pathology, but it may sometimes grow and cause serious neurologic manifestations. Little has been demonstrated yet about the epidemiology and etiology of TOLF.This study aimed to estimate the prevalence and clinical characteristics of TOLF.A cross-sectional study was carried out.All individuals who had undergone chest computed tomography (CT) for the evaluation of pulmonary disease or for medical examination for 1 year at our institute comprised the patient sample.Presence of TOLF and the association of these findings with thoracic kyphosis (TK), ossification of posterior longitudinal ligament (OPLL), space available for cord (SAC), age, gender, body mass index (BMI), and diabetes were the outcome measures.Prevalence and distribution of TOLF, TK, and concurrent OPLL were analyzed on CT scans. Through reviews of their medical records, clinical characteristics including age, gender, BMI, and diabetes were investigated. Logistic regression analysis was performed to determine the risk factors of TOLF.A total of 4,999 individuals (2,929 men and 2,070 women) were included for the analysis. Thoracic ossification of the ligamentum flavum was found in 1,090 individuals (674 men and 416 women. A single TOLF lesion was noted in 592 individuals and multiple lesions were noted in 498 individuals. The most commonly involved level was T10-T11. Distribution of TOLF showed two peaks: and the highest peak was at the lower thoracic spine (T10-12) and the second highest peak was at T3-T5. Thoracic kyphosis was 31.5°±9.5° in the TOLF group and 29.7°±8.9° in the non-TOLF group (p.001). Space available for cord/anteroposterior canal diameter ratio in TOLF level was 0.882. Logistic regression analysis showed that gender and TK were significantly associated with TOLF.Incidental TOLF was found in 21.8% of the study cohort. Gender and TK were related to TOLF.

Cu(In1-x,Gax)Se2 (CIGSe)-based solar cells have a high absorption coefficient (∼105), by which they can be used as thin-film solar cells that have the potential to be applied in various fields. To employ such a CIGSe-based solar cell as a transparent type, the conventional Mo substrate should be replaced with a transparent conductive oxide (TCO) substrate as the back electrode, and indium tin oxide (ITO) is one of the candidate TCO materials. However, various problems need to be addressed because the utilization of ITO may hinder solar cell performance, one of which is the contact occurring at the interface between CIGSe and ITO. This can be solved by adding an appropriate material at the interface while preserving the inherent purpose fulfilled by using the ITO electrode. In this study, we attempted to improve the contact properties using semi-metallic WTe2 flakes dispersed on the surface of the ITO substrate to form an electrical path between the CIGSe and the ITO substrate, which exhibit outstanding electrical conductivity among two-dimensional transition metal dichalcogenide materials. Accordingly, the effect of applying WTe2 flakes at the ITO and CIGSe interfaces on the performance of semi-transparent ultra-thin (STUT) CIGSe solar cells is discussed.

In this study, we synthesized porous (porosity: ~16%, average pore size: ~60 nm) ZnO nanosheets (thickness: ~80 nm) using a conventional solvothermal method to investigate NO2 gas sensing properties. Porous ZnO nanosheets triggered the detection of NO2 gas with high sensitivity. Responses of 2.93 – 0.5 ppm and 74.68 – 10 ppm NO2 gas at 200 °C were observed in the porous ZnO nanosheet-based gas sensor. In addition, improved sensing properties with high selectivity to NO2 gas, reasonable stability, and high response even in the presence of water vapor molecules were obtained. We found that the enhanced NO2 gas response of the porous ZnO nanosheet-based gas sensor was due to the synergetic effects of the high surface area, ZnO/ZnO homojunctions, and structural defects. We developed a highly sensitive NO2 gas sensor with improved reliability using morphologically engineered ZnO, which was prepared via a simple and scalable chemical-synthesis route.

Bi-Te-based materials have been used for room-temperature thermoelectric applications. However, n-type Bi2(Te,Se)3 thermoelectric alloys show a limited conversion efficiency, as compared to their p-type counterparts, thus hindering further widespread room-temperature applications. In this study, we investigated the enhanced thermoelectric properties of n-type Bi2(Te,Se)3 materials by the addition of Cu nanoparticles via a conventional high-energy ball milling process. The electrical and thermal transport properties were modulated by changing the amount of Cu nanoparticles. The power factor was enhanced by controlling the carrier, and the total thermal conductivity was reduced mainly due to the reduction in electronic thermal conductivity. Thus, dimensionless thermoelectric figure of merit (zT) at room temperature was enhanced for the Cu-added samples, and the highest zT value of 0.85 at 375 K was achieved in 2% Cu-doped Bi2Te2.7Se0.3. The average zT (zTavg) value between room temperature and 500 K was 0.79 for the 2% Cu-doped Bi2Te2.7Se0.3, which was 20% higher than that of the pristine Bi2Te2.7Se0.3, whereas a zT higher than 0.80 was sustained from room temperature to ~450 K. These results can lead to a high thermoelectric power generation efficiency of 7.6% at ΔT = 200 K.

Bipolar conduction in Bi-Te-based alloys is a critical barrier to high conversion efficiency in thermoelectric power generation applications. Herein, we investigate the effect of Te/Se ratio control on bipolar conduction in n-type Cu0.008Bi2(Te,Se)3. Based on the two-band model and Callaway model, we found that electronic and thermal transports of minority carriers (holes) were gradually decreased with an increase in Se content. The high-temperature power factor of Se-rich Cu0.008Bi2Te2.1Se0.9 was higher in value compared to reference Cu0.008Bi2Te2.7Se0.3 due to the weighted mobility ratio increase, and its bipolar thermal conductivity was significantly reduced simultaneously. As a result, a peak figure of merit (zT) of 0.92 was obtained at 440 K in Cu0.008Bi2Te2.1Se0.9.

Polycrystalline bulks of Sc-, Ti-, and V-doped n-type Cu 0.008 Bi 2 Te 2.7 Se 0.3 were prepared by melt solidification and spark plasma sintering, and their thermoelectric transport properties were investigated. The lattice thermal conductivity of Cu 0.008 Bi 2 Te 2.7 Se 0.3 was slightly reduced by intensified point defect phonon scattering by the substitution of Sc, Ti, and V atoms on the Bi-site. On the other hand, the power factor of Cu 0.008 Bi 2 Te 2.7 Se 0.3 was significantly enhanced by doping of V. Through the experimental and theoretical considerations, it was found that the enhanced power factor by V doping is originated from the increased density of states (DOS) effective mass by modified DOS near at Fermi level. Resultantly, an enhanced zT of 0.85 at 300 K was obtained in 1 at% V-doped Cu 0.008 Bi 2 Te 2.7 Se 0.3 (Cu 0.008 Bi 1.98 V 0.02 Te 2.7 Se 0.3 ).

Manipulation of thermal transport properties by defect engineering is an important but yet unresolved issue in thermoelectrics , since rational design strategies of multiple defect structures for minimizing lattice thermal conductivity are lacking. The key is to comprehend complex interaction between different frequency-dependent phonon scattering processes by multiple defect structures. Herein, individual contributions in lattice thermal conductivity reduction from each defect structure—point defects (0-dimensional, 0D), dislocations (1D), grain boundaries (2D), and nanoparticles (3D)—are characterized based on experimental results of commercial (Bi,Sb) 2Te3 -based alloys fitted to Debye-Callaway model. Then, the cumulative contributions by multiple defect structures are investigated interactively by estimating total phonon relaxation time. Therefore, the interactive role of multiple defect structures in reducing lattice thermal conductivity is elucidated. To extend the approach to other thermoelectric materials , PbTe-based alloys with multiple defect structures of point defects and grain boundaries were modeled as well. This approach enables to provide a thorough design of defect structures for realizing the experimentally attainable low lattice thermal conductivity in thermoelectric materials.

Nanostructuring is a universal strategy to improve the figure of merit (zT) of thermoelectric (TE) materials by the substantial decrease of lattice thermal conductivity due to the intensive scattering of phonons at interfaces. However, nanostructured bismuth antimony telluride alloys with foreign nanosized phases usually suffer from the degradation of carrier mobility at incoherent interfaces. The results reported here describe an approach to generate intrinsic Sb-rich precipitates that have a synchronal effect on micro-grained Bi0.5Sb1.5Te3 alloy. The designed formation of nanosized Sb-rich precipitates by dissolving excess Pb into Bi0.5Sb1.5Te3 matrix intensifies the phonon scattering and modulates the carrier transport simultaneously. By employing density functional theory calculation, transmission electron microscope and atom probe tomography, the role of Pb substituting for Sb site on the evolution of Sb-rich nanophase is clarified and the compositions and crystal structures of the precipitated Sb-rich phases are analyzed, revealing various interface structures. The optimized Bi0.5Sb1.5Te3 + 0.22 wt.% Pb sample shows a maximum zT value of 1.32 at 400 K with an outstanding average zT value of 1.2 over 300 K to 500 K. This work identifies the hidden role of intrinsic Sb-rich precipitates in Bi0.5Sb1.5Te3 alloys and provides an effective way beyond nanostructuring to develop high-performance bismuth antimony telluride thermoelectric alloys.

The effect of Br substitution on enhancing the thermoelectric properties of n-type layered SnSe2 is investigated characterizing SnSe2-xBrx synthesized with various Br contents (x = 0, 0.004, 0.008, 0.01, and 0.02). The electrical conductivity systematically increases with an increase in x owing to the simultaneous increase in both the carrier concentration (n) and mobility. As x increases, n increases by ~100 times; however, the magnitude of the Seebeck coefficient (|S|) decreases from 600 to 229 μV/K, resulting in an enhanced power factor at room temperature. The density functional theory calculations support that the valley degeneracy at the conduction band minimum increases with the Br substitution in SnSe2, while the conduction band minimum becomes flatter. This finding indicates that the increased density-of-state effective mass leads to the relatively large |S| even under a considerably increased n. Combined with the slight decrease in the thermal conductivity with an increase in x without significant additional phonon scattering, a thermoelectric figure of merit (zT) of 0.62 at 750 K is obtained for SnSe1.98Br0.02 (x = 0.02), which is 50% higher than that for non-doped SnSe2.

Molybdenum disulfide (MoS2) films possess intrinsic n-type conductivity, and thus development of p-type MoS2 films for realizing practical next-generation complementary metal oxide semiconductor devices is extremely challenging. The use of dopants is a well-known conventional approach for engineering intrinsic conductivity with improved device performance. Herein, we demonstrate the n-type conductivity suppressing property of the tellurium (Te)-doped multilayer MoS2, grown by metal-organic chemical vapor deposition. The back-gated as-grown Te-doped multilayer MoS2 field-effect transistor (FET) is observed to exhibit p-type behavior with a maximum mobility of 0.036 cm2/V·s, ON/OFF current ratio of 7.8 × 103, and a Schottky barrier height of 32 meV. A quantitative Schottky barrier height of a p-type multilayer MoS2-based FET with Au electrode has been obtained by analyzing its low-temperature transport characteristics. Enhanced device performance has been achieved by doping the p-type MoS2 transistors in a back-gate structure and high-K dielectric gate insulators with Te. pFET devices containing Al2O3 dielectric insulators exhibit extremely high performance, including a maximum mobility of ∼182 cm2/V·s, maximum ON/OFF current ratio of ∼105, and a low subthreshold swing of ∼215 mV/dec. These improvements have been attributed to the charge screening effect associated with the high-K dielectrics and a low Schottky barrier height.

Magnetic field ( H ) sweeping direction dependences of the mixed voltage V mix induced by the inverse-spin Hall effect(ISHE) and spin-rectified effect (SRE) in a CoFeB (5 nm)/Pt (10 nm) bilayer structure are investigated using the ferromagnetic resonance in the TE mode cavities and coplanar waveguide methods. Conventionally, the magnitude of ISHE voltage V ISH (symmetric) excluding the SRE (antisymmetric component) was unavoidably separated from the fitting curve of V mix (a sum of a symmetric and an antisymmetric part) for one direction of H -source. By studying the ratio of the two voltage parts with the bi-directional H sweeping, the optimized V ISH (no SRE condition) value which also include a well-defined spin Hall angle can be obtained via the linear response relation of ISHE and SRE components.