Synthesis of Ag Nanostructures by Photochemical Reduction Using Citrate-Capped Pt Seeds

A simple synthesis of Ag nanostructures such as nanorods and nanowires has been demonstrated with citrate-capped Pt seeds. UV-visible spectra and photographs of the synthesized solutions at different UV exposure times showed that the citrate-capped Pt seed played a crucial role in the growth of Ag nanostructures. After UV exposure of the colloidal solution for 60 min, the average diameter, length, and aspect ratio of the Ag nanostructures were about 95 nm, 2.1 nm, and 22, respectively. The photochemical reduction is hypothesized to result from photoelectron transfer from adsorbed citrate to Pt nanoparticle seed allowing Ag ions to form Ag nanostructures. Based on X-ray diffraction spectra and transmission electron microscope images, the synthesized Ag nanostructures were a face-centered cubic single crystal with good purity. These results suggest that the photochemical reduction method can provide Ag nanostructures in the presence of citrate-capped Pt seeds at room temperature for anisotropic Ag products

Nasopharynx as a Microbiologic Reservoir in Chronic Suppurative Otitis Media: Preliminary Study

ObjectivesThe present study was designed to identify the correlations of bacterial strains of the middle ear and the nasopharynx in chronic suppurative otitis media (CSOM) patients who were scheduled for operations.MethodsSixty-three patients with CSOM were enrolled in the study. Culture specimens were collected from the middle ear and nasopharynx of patients who were admitted for operation. Samples collections were performed 3 times; from the middle ear and nasophaynx at the admission day, from the middle ear during the operation, and from the external auditory canal post-operatively. Bacteria were identified by gram staining and biochemical tests. The correspondence rate of organisms which simultaneously exist in the middle ear and the nasopharynx was measured.ResultsSixty-eight organisms were isolated from the middle ear and 57 organisms from the nasopharynx among 63 patients. Of 68 bacteria identified in middle ear, 26.52% (18 bacteria) corresponded with those of nasopharynx. MRSA had the high correspondence rate, and of 18 methicillin-resistant Staphylococcus aureus (MRSA) isolated from middle ear, 33.3% (6 bacteria) corresponded with nasophaynx. Meanwhile, 3 organisms of MRSA were detected from the external auditory canal post-operatively, although they were only found in nasopharynx pre-operatively.ConclusionThe current trend of middle ear swab alone for bacterial detection would be insufficient to identify the potent MRSA and impede early antibiotic intervention for the effective middle ear surgery. Therefore, it is necessary to perform nasopharynx cultures together with conventional middle ear culture to control potent risk for infection pre-operatively

Electron−hole separation in ferroelectric oxides for efficient photovoltaic responses

Despite their potential to exceed the theoretical Shockley−Queisser limit, ferroelectric photovoltaics (FPVs) have performed inefficiently due to their extremely low photocurrents. Incorporating Bi₂FeCrO₆(BFCO) as the light absorber in FPVs has recently led to impressively high and record photocurrents [Nechache R, et al. (2015) Nat Photonics 9:61–67], which has revived the FPV field. However, our understanding of this remarkable phenomenon is far from satisfactory. Here, we use first-principles calculations to determine that such excellent performance mainly lies in the efficient separation of electron− hole (e-h) pairs. We show that photoexcited electrons and holes in BFCO are spatially separated on the Fe and Cr sites, respectively. This separation is much more pronounced in disordered BFCO phases, which adequately explains the observed exceptional PV responses. We further establish a design strategy to discover next-generation FPV materials. By exploring 44 additional Bi-based double-perovskite oxides, we suggest five active-layer materials that offer a combination of strong e-h separations and visible-light absorptions for FPV applications. Our work indicates that charge separation is the most important issue to be addressed for FPVs to compete with conventional devices. Keywords: ferroelectrics; double perovskites; photovoltaics; e-h separation; density functional theor

Spontaneous Tonsillar Hemorrhage and Post-Tonsillectomy Hemorrhage

Spontaneous tonsillar hemorrhage from infectious causes is extremely rare and post-tonsillectomy hemorrhage, although also relatively rare, is an unavoidable complication of the procedure. Hemorrhage in association with tonsillitis or tonsillectomy is potentially dangerous and can be life threatening. We report here the presentation and management of a 42-yr-old man with severe spontaneous hemorrhage from infected tonsils and post-tonsillectomy hemorrhage. We suggest that if attempts to control the bleeding are not successful or if severe spontaneous tonsillar hemorrhage occurs repeatedly or a malignancy is suspected, tonsillectomy and close postoperative follow up is recommended

Characteristics of Hearing Loss Among Older Adults in the Korean Genome and Epidemiology Study: A Community-Based Longitudinal Cohort Study With an 8-Year Follow-up

Objectives. This study investigated the 8-year incidence and progression of hearing loss (HL) and its types and examined the risk factors for changes in HL. Methods. This longitudinal cohort study analyzed data from the Korean Genome and Epidemiology Study (KoGES), an ongoing, prospective, community-based cohort study that has been conducted since 2001. Altogether, 1,890 residents of urban areas in Korea aged 45–75 years at time 1 (baseline) were included in the study. Pure-tone audiometry (PTA) testing was performed twice, at time 1 (2008–2009) and time 2 (2015–2018, follow-up), 8 years apart. HL grades were defined as seven mutually exclusive categories following the revised World Health Organization classification. Incidence was defined as PTA >20 dB HL in the better ear at time 2 among those without HL at time 1. Progression was defined as the progressive deterioration of HL among those with HL at time 1. The three types of HL constituted sensorineural (SNHL), conductive, and mixed HL. Results. At time 1, 36.40% of patients were diagnosed with HL, which increased to 51.64% at time 2. The 8-year incidence of HL was 27.20%, and progressive deterioration of HL occurred in 23.11% of those with HL. SNHL was the most common type of HL, and its prevalence markedly increased at time 2. Multivariate analysis demonstrated that the incidence of HL was significantly associated with increasing age, male sex (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.07–2.81), and diabetes mellitus (OR, 1.43; 95% CI, 1.04–1.96). Alcohol consumption was a risk factor for HL deterioration among those with HL at time 1. Conclusion. The prevalence and deterioration of HL were extremely high among older adults, and age was the strongest risk factor for these changes. Therefore, timely screening and intervention are necessary to prevent HL and delay its deterioration among older adults

Osseointegration of Implants Surface-Treated with Various Diameters of TiO 2

The aim of this study was to evaluate the osseointegration of implants which were surface-treated with various diameters of TiO2 nanotubes (30 nm, 70 nm, and 100 nm) in rabbit. Resorbable blast media (RBM) surfaced implants (Osstem, Busan, Korea) 3.5 mm in diameter and 8.5 mm in length were designated as the control group and the implants surface-treated with various diameters of nanotubes (30 nm, 70 nm, and 100 nm) with the same shapes were designated as the experimental groups. The implants were maintained unloaded for 4 and 12 weeks. After this period, the animals were sacrificed and micro-CT analysis, histomorphometric analysis (bone to implant contact (BIC), bone volume (BV)), and removal torque test were performed. Micro-CT analysis, histomorphometric analysis, and removal torque test results all showed the similar pattern, showing that 70 nm experimental group had the highest value at 4 weeks while 30 nm experimental group had the highest value at 12 weeks. Therefore, on the basis of the results above, it can be concluded that 30 nm and 70 nm TiO2 nanotubes may have positive effects on osteogenesis and osseointegration depending on the healing time

Variations in gut microbiota associated with changes in life-history traits of Daphnia galeata induced by fish kairomones

The gut microbiota plays a crucial role in host physiology and the disruption of host–microbiota relationships caused by environmental stressors can impact host growth and survival. In this study, we used Daphnia galeata as a model organism to investigate the interactive effects of fish kairomones on the life-history traits and gut microbiota alterations of D. galeata, as well as the relationship between life-history traits and gut microbiota composition. The presence of fish kairomones enhanced fecundity, decreased growth, and altered gut microbiota, with significant changes in alpha diversity but not in beta diversity in the genotype KB5 of D. galeata. Statistical analysis revealed that the relative abundance of the Pseudomonadaceae family significantly increased upon exposure to fish kairomone, while the relative abundance of the Comamonadaceae family significantly decreased. The decreased growth in genotype KB5 may be associated with a significant increase in Pseudomonas, a member of the family Pseudomonadaceae, which is generally deficient in essential fatty acids, potentially negatively impacting growth. Meanwhile, it is speculated that the significant decrease in Limnohabitans belonging to the Comamonadaceae family is associated with the reduction of body size and increased fecundity of KB5 when exposed to fish kairomones. Furthermore, the genus Candidatus Protochlamydia was observed only under the fish kairomones-treated condition. These data suggest that variations in host life-history traits related to reproduction and growth are potentially associated with the relative abundance or presence of these microbial genera. Our research findings provide valuable insights into understanding the impact of biotic stress on the interaction between hosts and microbiota

The Management of Cardiovascular Abnormalities in Patient With LEOPARD Syndrome

LEOPARD syndrome (LS) is a rare hereditary disorder in Asian countries. This syndrome consists of multiple systemic abnormalities. In particular, characteristic cardiovascular effects in LS may include variable clinical manifestations from benign to life-threatening courses. The cardiac effects of this syndrome consist of left ventricular hypertrophy (LVH), pulmonary stenosis (PS), coronary artery dilatation and electrocardiogram(ECG) abnormalities. Since there are few LS patients who have undergone a complete cardiovascular evaluation, the nature and clinical prognosis of cardiovascular abnormalities in this syndrome remain uncertain. Also, there have been few reports on therapeutic strategies for cardiovascular abnormalities in LS. Here we describe a case of LS who presented with multiple cardiovascular problems and underwent successful surgical and medical treatment