Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 112
Filtrar
1.
J Clin Med ; 13(8)2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38673584

RESUMO

Background/Objectives: Diabetic foot ulcers are one of the complications in patients with diabetes, which can be caused by infection, neuropathy, and blood vessel disorder. Among them, infection is the most common cause, and if it becomes worse, amputation may be necessary. So, it is important to detect and treat infections early, and determining indicators that can confirm infection is also important. Known infection markers include white blood cells (WBCs), the erythrocyte sediment rate (ESR), C-reactive protein (CRP), and procalcitonin, but they are not specific to diabetic foot ulcers. Presepsin, also known as soluble CD14, is known to be an early indicator of sepsis. Recent studies have reported that presepsin can be used as an early indicator of infection. This study investigated whether presepsin could be used as an early marker of severe infection in patients with diabetic foot ulcers. Methods: We retrospectively studied 73 patients who were treated for diabetic foot ulcerations from January 2021 to June 2023 at Yeungnam University Hospital. Results: Out of a total of 73 patients, 46 patients underwent amputations with severe infections, and the WBC level, ESR, and CRP, procalcitonin, and presepsin levels were significantly higher in the group of patients who underwent amputations. The cutoff of presepsin, which can predict serious infections that need amputation, was 675 ng/mL. A regression analysis confirmed that presepsin, HbA1c, and osteomyelitis significantly increased the risk of severe infections requiring amputation. Conclusions: Presepsin will be available as an early predictor of patients with severe infections requiring amputations for diabetic foot ulcerations.

2.
RSC Adv ; 13(40): 28160-28164, 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37753393

RESUMO

Understanding the precise effects of defects on the photophysical properties of quantum dots (QDs) is essential to their development with near-unity luminescence. Because of the complicated nature of defects in QDs, the origins and detailed roles of the defects still remain rarely understood. In this regard, we used detailed chemical analysis to investigate the effect of surface defects on the optical properties of InP/ZnSe/ZnS QDs by introducing shell defects through controlled trifluoroacetic acid (TFA) etching. TFA treatment on the InP/ZnSe/ZnS QDs partially removed the ZnS shell as well as ligands and reduced the quantum yield by generating energetically deep surface traps. The surface defects of QDs by TFA cause charged trap sites inducing an Auger recombination process with a rate of ca. 200 ps. Based on these results, we proposed possible trap-assisted non-radiative decay pathways between the band-edge state and surface deep traps in InP/ZnSe/ZnS QDs.

3.
J Korean Med Sci ; 38(21): e160, 2023 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-37270915

RESUMO

We assessed the risk factors for major amputation of diabetic foot ulcers (DFUs) in patients with diabetic kidney disease (DKD) stages 3b-5. For DFU assessment, in addition to DFU location and presence of infection, ischemia, and neuropathy, vascular calcification was assessed using the medial arterial calcification (MAC) score. Of 210 patients, 26 (12.4%) underwent major amputations. Only the location and extension of DFU, represented by Texas grade differed between the minor and major amputation groups. However, after adjusting for covariates, ulcer location of mid- or hindfoot (vs. forefoot, odds ratio [OR] = 3.27), Texas grades 2 or 3 (vs. grade 0, OR = 5.78), and severe MAC (vs. no MAC, OR = 4.46) was an independent risk factor for major amputation (all P < 0.05). The current use of antiplatelets was a possible protective factor for major amputations (OR = 0.37, P = 0.055). In conclusion, DFU with severe MAC is associated with major amputation in patients with DKD.


Assuntos
Diabetes Mellitus , Pé Diabético , Nefropatias Diabéticas , Humanos , Pé Diabético/complicações , Pé Diabético/cirurgia , Nefropatias Diabéticas/complicações , Fatores de Risco , Amputação Cirúrgica , Estudos Retrospectivos
4.
Arch Plast Surg ; 50(3): 311-314, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37256041

RESUMO

In lower extremity reconstruction, the recipient vessel often requires long-range mechanical dilation because of extensive vasospasm or plaque formation induced by concomitant atherosclerosis. While a forceps dilator can be used to manipulate and dilate vessels approximately 1 cm from their end, a DeBakey vascular dilator can dilate long-range vessels. The authors successfully performed free flap reconstruction of the lower extremity using the DeBakey vascular dilator. Of the two patients who underwent lower extremity reconstruction, one had extensive vasospasm, and the other had plaques in the recipient arteries. Irrigation with 4% lidocaine and dilation of the lumen with a forceps dilator were insufficient to restore the normal arterial blood flow. Instead, a DeBakey vascular dilator with a 1-mm diameter tip was gently inserted into the lumen. Then, to overcome vessel resistance, the dilator gently advanced approximately 10 cm to dilate the recipient artery. Normal arterial blood flow was gushed out after dilating the vessel lumen using a DeBakey vascular dilator. The vascular anastomosis was performed, and intravenous heparin 5000 IU was administered immediately after anastomosis. Prophylactic low-molecular-weight-heparin (Clexane, 1 mg/kg) was administered subcutaneously to both patients for 14 days. The reconstructed flap survived without necrosis in either patient.

5.
J Colloid Interface Sci ; 643: 465-479, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37088050

RESUMO

The cleaning solution for the post-chemical mechanical planarization (post-CMP) process of tungsten in neutral-alkaline media requires corrosion inhibitors as an additive, especially for advanced devices where the device node size shrinks below 10 nm. In the present study, the corrosion inhibition performance of benzethonium chloride (BTC) is evaluated in neutral-alkaline conditions. The electrochemical impedance spectroscopy (EIS) analysis showed âˆ¼ 90 % of corrosion inhibition efficiency with an optimum concentration of 0.01 wt% BTC at both pH 7 and 11. Langmuir adsorption isotherm, frontier molecular orbital theory, molecular simulation, contact angle, precipitation study, and X-ray photoelectron spectroscopy analysis were performed to identify the inhibition mechanism of the BTC molecule on the W surface. Based on the proposed mechanism, the electrostatic attraction between the positively charged N atom in the BTC molecule and the negatively charged W surface initiates the adsorption of the molecule. The high dipole moment and large molecular size enhance the physical adsorption of the molecule to the surface. In addition to this, the adsorption isotherm analysis shows that possible chemical interaction with a moderate value of Gibbs free energy change of adsorption exists between the W and BTC molecule. The excellent corrosion inhibition efficiency of BTC on W is confirmed by the frontier molecular orbital theory and molecular dynamic simulation analysis.

6.
J Clin Med ; 12(5)2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36902672

RESUMO

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a T-cell non-Hodgkin's lymphoma that occurs in patients with at least one prior textured breast implant. BIA-ALCL has a relatively good prognosis when treated promptly. However, data on the methods and timing of the reconstruction process are lacking. Herein, we report the first case of BIA-ALCL in Republic of Korea in a patient who underwent breast reconstruction using implants and an acellular dermal matrix (ADM). A 47-year-old female patient was diagnosed with BIA-ALCL stage IIA (T4N0M0) and underwent bilateral breast augmentation using textured breast implants. She then underwent removal of both breast implants, total bilateral capsulectomy, adjuvant chemotherapy, and radiotherapy. There was no evidence of recurrence at 28 months postoperatively; therefore, the patient wished to undergo breast reconstruction surgery. A smooth surface implant was used to consider the patient's desired breast volume and body mass index. The right breast was reconstructed with a smooth surface implant and an ADM in the prepectoral plane. Breast augmentation was performed on the left breast using a smooth surface implant. The patient was satisfied with the results and recovered fully with no complications.

7.
Stem Cell Res Ther ; 14(1): 22, 2023 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-36750973

RESUMO

BACKGROUND: Adipose-derived stem cells (ASCs) have been reported to reduce fibrosis in various tissues. In this study, we investigated the inhibitory role of ASCs on capsule formation by analyzing the histologic, cellular, and molecular changes in a mouse model of peri-implant fibrosis. We also investigated the fate and distribution of ASCs in the peri-implant capsule. METHODS: To establish a peri-implant fibrosis model, customized silicone implants were inserted into the dorsal site of C57BL/6 wild-type mice. ASCs were harvested from the fat tissues of transgenic mice that express a green fluorescent protein (GFP-ASCs) and then injected into the peri-implant space of recipient mice. The peri-implant tissues were harvested from postoperative week 2 to 8. We measured the capsule thickness, distribution, and differentiation of GFP-ASCs, as well as the cellular and molecular changes in capsular tissue following ASC treatment. RESULTS: Injected GFP-ASCs were distributed within the peri-implant capsule and proliferated. Administration of ASCs reduced the capsule thickness, decreased the number of myofibroblasts and macrophages in the capsule, and decreased the mRNA level of fibrogenic genes within the peri-implant tissue. Angiogenesis was enhanced due to trans-differentiation of ASCs into vascular endothelial cells, and tissue hypoxia was relieved upon ASC treatment. CONCLUSIONS: We uncovered that implanted ASCs inhibit capsule formation around the implant by characterizing a series of biological alterations upon ASC treatment and the fate of injected ASCs. These findings highlight the value of ASCs for future clinical applications in the prevention of capsular contracture after implant-based reconstruction surgery.


Assuntos
Tecido Adiposo , Células Endoteliais , Camundongos , Animais , Proteínas de Fluorescência Verde , Camundongos Endogâmicos C57BL , Fibrose , Camundongos Transgênicos , Células-Tronco
8.
J Neurointerv Surg ; 15(11): 1095-1104, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36596671

RESUMO

BACKGROUND: Antiplatelet therapy, where regimens are tailored based on platelet function testing, has been introduced into neurointerventional surgery. This nationwide registry study evaluated the effect and safety of tailored antiplatelet therapy in stent assisted coiling for unruptured aneurysms compared with conventional therapy using a standard regimen. METHODS: This study enrolled 1686 patients in 44 participating centers who received stent assisted coiling for unruptured aneurysms between January 1, 2019 and December 31, 2019. The standard regimen (aspirin and clopidogrel) was used for all patients in the conventional group (924, 19 centers). The regimen was selected based on platelet function testing (standard regimen for clopidogrel responders; adding cilostazol or replacing clopidogrel with other thienopyridines (ticlopidine, prasugrel, or ticagrelor) for clopidogrel non-responders) in the tailored group (762, 25 centers). The primary outcome was thromboembolic events. Secondary outcomes were bleeding and poor outcomes (increase in modified Rankin Scale score). Outcomes within 30 days after coiling were compared using logistic regression analysis. RESULTS: The thromboembolic event rate was lower in the tailored group than in the conventional group (30/762 (3.9%) vs 63/924 (6.8%), adjusted OR 0.560, 95% CI 0.359 to 0.875, P=0.001). The bleeding event rate was not different between the study groups (62/762 (8.1%) vs 73/924 (7.9%), adjusted OR 0.790, 95% CI 0.469 to 1.331, P=0.376). Poor outcomes were less frequent in the tailored group (12/762 (1.6%) vs 34 (3.7%), adjusted OR 0.252, 95% CI 0.112 to 0.568, P=0.001). CONCLUSION: Tailored antiplatelet therapy in stent assisted coiling for unruptured aneurysms reduced thromboembolic events and poor outcomes without increasing bleeding.


Assuntos
Embolização Terapêutica , Aneurisma Intracraniano , Tromboembolia , Humanos , Inibidores da Agregação Plaquetária/uso terapêutico , Clopidogrel , Aneurisma Intracraniano/terapia , Embolização Terapêutica/efeitos adversos , Tromboembolia/terapia , Stents , Sistema de Registros , Estudos Retrospectivos , Resultado do Tratamento
9.
J Cerebrovasc Endovasc Neurosurg ; 25(2): 132-142, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36693396

RESUMO

OBJECTIVE: Dual antiplatelet therapy (DAPT) is usually temporarily used after stent-assisted coil embolization (SACE), and is commonly converted to mono antiplatelet therapy (MAPT) for indefinitely. In this study, we aimed to find the possibility of discontinuing MAPT, and to determine the proper period of DAPT use. METHODS: We used the Standard Sample Cohort DB dataset from the National Health Insurance Sharing Service. Among approximately 1 million people in the dataset, SACE was performed in 214 patients whose data this study analyzed. The relationship between discontinuation of antiplatelet therapy and intracranial hemorrhage or cerebral infarction was analyzed using multiple logistic regression, considering all confounding variables. The survival rate according to the continuation of antiplatelet therapy was obtained using Kaplan-Meier analysis, and the difference in survival rate according to the continuation of antiplatelet therapy was verified using the log-rank test. The hazard ratio according to continuation of antiplatelet therapy was obtained using the Cox proportional hazards model. The analysis was conducted by applying the same statistical method to the duration of DAPT use. RESULTS: Among 214 patients who underwent SACE, 50, 159 and five patients continued, discontinued and did not use antiplatelet therapy (except at the time of procedure), respectively. In multiple logistic regression analysis, discontinuation of antiplatelet agents (including aspirin) and the period of DAPT use did not affect the occurrence of intracranial hemorrhage or cerebral infarction, considering various confounding factors. In the survival analysis according to the continuation of antiplatelet agents, patients who continued to use antiplatelet agents had a higher survival rate than those in other groups (p=0.00). The survival rate was higher in the rest of the group than in the group that received DAPT for three months (p=0.00). CONCLUSIONS: Continuation of antiplatelet agents or the period of DAPT use did not affect the occurrence of intracranial hemorrhage or cerebral infarction. Considering the survival rate, it would be better to maintain at least three months of antiplatelet therapy and it might be recommended to continue DAPT use for 12 months.

11.
J Clin Med ; 11(7)2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35407582

RESUMO

Forefoot osteomyelitis can be an extremely challenging problem in orthopedic surgery. Unlike conventional methods, such as amputations, antibiotic impregnated cement space (ACS) was recently introduced and perceived as a substitute for amputation. The purpose of this study was to compare clinical features between diabetic and non-diabetic groups and to evaluate the efficacy of ACS in the treatment of forefoot osteomyelitis, by identifying the clinical characteristics of ACS. We inserted ACS into the forefoot osteomyelitis patients and regularly checked up on them, then analyzed the clinical features of the patients and failure reasons, if ACS had to be removed. Average survival rate of ACS was 60% (21 out of 35 cases) and main failure reason was recurrence of infection. There was no significant clinical difference between diabetic and non-diabetic groups. We concluded that ACS could be a possible way of avoiding amputation if infection is under control. ACS seems to be an innovative method with promising results for foot osteomyelitis, but widely accepted indications need to be agreed upon.

12.
J Cosmet Dermatol ; 21(10): 4754-4764, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35034416

RESUMO

BACKGROUND: Dermal delivery is versatile in therapeutics as well as cosmetics in pursuit of enhancing safety/efficacy and alleviating pain/fear to alternate oral/injective administrations. Natural siliceous spicules offer a potential approach via simple topical medications to circumvent poor penetrations through the skin barrier by loading, carrying, and releasing the active ingredients in a highly efficient and controlled manner. AIMS: The delivery of ingredients loaded on spicules is assessed to improve the dermal efficacy compared to simple topical treatments. METHODS: First, needle-like spicules were isolated from natural freshwater sponges. Then, the active ingredient was loaded via liposome formations. Finally, the dermal efficiency was evaluated. RESULTS: Natural siliceous spicules were purified, sorted, and fully characterized to appear 250 µm of length and 12 µm of diameter on average. A model ingredient, pectolinarin, was efficiently loaded onto the internal space of spicules via lecithin-based liposome formations. The penetration was visualized using a porcine skin sample with a fluorescent dye and assessed quantitatively by a Franz diffusion cell system. Dermal absorption rate was measured 73.4%, while the percutaneous penetration rate was 2.2%. The release pattern turned out a simple diffusion analyzed by Fick's law and Higuchi model. The liposomes loaded onto spicules were further stabilized by a hydrophobic capsulation, which may benefit the overall efficacy of the ingredient. CONCLUSION: A novel dermal delivery system is beneficial to improve the topical efficacy of biologically active ingredients. The outcomes shed a light upon developing skin-protective/improving cosmetics and therapeutics with enhanced performance.


Assuntos
Cosméticos , Lipossomos , Suínos , Animais , Lipossomos/metabolismo , Absorção Cutânea , Pele/metabolismo , Administração Tópica
13.
Front Neurol ; 13: 1080244, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36605785

RESUMO

Background and objective: Inflammation is an important factor in the development of aneurysm, and has been identified as a key characteristic predictive of rupture of intracranial aneurysm (IA). However, the role of inflammatory peripheral blood cell ratios in patients with IA has not been well delineated. Methods: A total of 1,209 patients, including 1,001 with unruptured IA and 208 with ruptured IA, were enrolled in this study. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), platelet-to-neutrophil ratio (PNR), and platelet-to-white-blood-cell ratio (PWR) were compared between ruptured and unruptured IA. Results: Compared with the ruptured IA group, the unruptured IA group had higher PNR {median, 65.96 [interquartile range (IQR) 48.95-85.05] vs. 37.78 (IQR, 23.17-54.05); p < 0.001} and PWR [median, 36.89 (IQR 29.38-44.56) vs. 22.39 (IQR, 16.72-29.29); p < 0.001]. In multivariate analysis, PNR and PWR were independently associated with ruptured IA (p = 0.001 and p < 0.001, respectively). Unruptured IA subgroup analyses according to the PHASES scores showed that a higher PHASES score was associated with significantly higher NLR and erythrocyte sedimentation rate (p < 0.001 and p = 0.025) and lower PNR and PWR (p < 0.001 and p = 0.007). Conclusions: We demonstrated that lower PNR and PWR levels are associated with ruptured IA and a higher PHASES score. Unlike many other inflammatory markers and bioassays, peripheral blood cell ratios are inexpensive and readily available biomarkers that may be useful for risk stratification in patients with cerebral aneurysm. However, a long-term prospective study is needed to clarify this matter.

14.
Ultrason Sonochem ; 82: 105859, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34969001

RESUMO

Acoustic cavitation is used for megasonic cleaning in the semiconductor industry, especially of wafers with fragile pattern structures. Control of transient cavitation is necessary to achieve high particle removal efficiency (PRE) and low pattern damage (PD). In this study, the cleaning performance of solutions with different concentrations of dissolved gas (H2) and anionic surfactant (sodium dodecyl sulfate, SDS) in DIW (DI water) on silicon (Si) wafers was evaluated in terms of PRE and PD. When only DIW was used, PRE was low and PD was high. An increase in dissolved H2 gas concentration in DIW increased PRE; however, PD also increased accordingly. Thus, we investigated the megasonic cleaning performance of DIW and H2-DIW solutions with various concentrations of the anionic surfactant, SDS. At 20 ppm SDS in DIW, PRE reached a maximum value and then decreased with increasing concentration of SDS. PRE decreased slightly with increasing concentrations of SDS surfactant when dissolved in H2-DIW. Furthermore, PD decreased significantly with increasing concentrations of SDS surfactant in both DIW and H2-DIW cases. A high-speed camera setup was introduced to analyze bubble dynamics under a 0.96 MHz ultrasonic field. Coalescence, agglomeration, and the population of multi-bubbles affected the PRE and PD of silicon wafers differently in the presence of SDS surfactant. We developed a hypothesis to explain the change in bubble characteristics under different chemical environmental conditions.

15.
Nutr Res Pract ; 15(6): 703-714, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34858549

RESUMO

BACKGROUND/OBJECTIVES: A dietary restriction on the intake of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) has been reported to be effective in the treatment of gastrointestinal (GI) tract complications. Enteral nutrition (EN) is widely used for patients who cannot obtain their nutritional requirements orally, but many studies have reported EN complications, especially diarrhea, in up to 50% of patients. SUBJECTS/METHODS: We performed a single-center, non-randomized, controlled trial to determine the effects of a low-FODMAP enteral formula on GI complications in patients in intensive care units (ICUs). Patients in the ICU who needed EN (n = 66) were alternately assigned to the low-FODMAP group (n = 33) or the high-FODMAP group (n = 33). RESULTS: Anthropometric and biochemical parameters were measured, and stool assessment was performed using King's Stool Chart. We excluded patients who received laxatives, GI motility agents, proton pump inhibitors, antifungal agents, and antibiotics other than ß-lactams. There were no differences in GI symptoms during 7 days of intervention, including bowel sound, abdominal distension, and vomiting between the 2 groups. However, diarrhea was more frequent in the high-FODMAP group (7/33 patients) than the low-FODMAP group (1/33 patients) (P = 0.044). CONCLUSIONS: Our results suggest that a low-FODMAP enteral formula may be a practical therapeutic approach for patients who exhibit enteral formula complications. Our study warrants further randomized clinical trials and multicenter trials. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0005660.

16.
ACS Omega ; 6(47): 31876-31890, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34870010

RESUMO

Stretchable electrode materials have attracted great attention as next-generation electronic materials because of their ability to maintain intrinsic properties with rare damage when undergoing repetitive deformations, such as folding, twisting, and stretching. In this study, an electrically conductive PDMS nanocomposite was manufactured by combining the hybrid nanofillers of carbon nanotubes (CNTs) and silver nanowires (AgNWs). The amphiphilic isopropyl alcohol molecules temporarily adhered simultaneously to the hydrophobic CNT and hydrophilic AgNW surfaces, thereby improving the dispersity. As the CNT/AgNW ratio (wt %/wt %) decreased under the constant nanofiller content, the tensile modulus decreased and the elongation at break increased owing to the poor interaction between the AgNWs and matrix. The shear storage moduli of all nanocomposites were higher than the loss moduli, indicating the elastic behavior with a cross-linked network. The electrical conductivities of the nanocomposite containing the hybrid nanofillers were superior to those of the nanocomposite containing either CNT or AgNW at the same filler content (4 wt %). The hybrid nanofillers were rearranged and deformed by 5000 cyclic strain tests, relaxing the PDMS matrix chain and weakening the interfacial bonding. However, the elastic behavior was maintained. The dynamic electrical conductivities gradually increased under the cyclic strain tests due to the rearrangement and tunneling effect of the nanofillers. The highest dynamic electrical conductivity (10 S/m) was obtained for the nanocomposite consisting of 2 wt % of CNTs and 2 wt % of AgNWs.

17.
Sci Rep ; 11(1): 19889, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34615961

RESUMO

Colloidal quantum-dots (QDs) are highly attractive materials for various optoelectronic applications owing to their easy maneuverability, high functionality, wide applicability, and low cost of mass-production. QDs usually consist of two components: the inorganic nano-crystalline particle and organic ligands that passivate the surface of the inorganic particle. The organic component is also critical for tuning electronic properties of QDs as well as solubilizing QDs in various solvents. However, despite extensive effort to understand the chemistry of ligands, it has been challenging to develop an efficient and reliable method for identifying and quantifying ligands on the QD surface. Herein, we developed a novel method of analyzing ligands in a mild yet accurate fashion. We found that oxidizing agents, as a heterogeneous catalyst in a different phase from QDs, can efficiently disrupt the interaction between the inorganic particle and organic ligands, and the subsequent simple phase fractionation step can isolate the ligand-containing phase from the oxidizer-containing phase and the insoluble precipitates. Our novel analysis procedure ensures to minimize the exposure of ligand molecules to oxidizing agents as well as to prepare homogeneous samples that can be readily analyzed by diverse analytical techniques, such as nuclear magnetic resonance spectroscopy and gas-chromatography mass-spectrometry.

19.
Small ; 17(52): e2102792, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34636144

RESUMO

Non-toxic InP-based nanocrystals have been developed for promising candidates for commercial optoelectronic applications and they still require further improvement on photophysical properties, compared to Cd-based quantum dots (QDs), for better device efficiency and long-term stability. It is, therefore, essential to understand the precise mechanism of carrier trapping even in the state-of-the-art InP-based QD with near-unity luminescence. Here, it is shown that using time-resolved spectroscopic measurements of systematically size-controlled InP/ZnSe/ZnS core/shell/shell QDs with the quantum yield close to one, carrier trapping decreases with increasing the energy difference between band-edge and trap states, indicating that the process follows the energy gap law, well known in molecular photochemistry for nonradiative internal conversion between two electronic states. Similar to the molecular view of the energy gap law, it is found that the energy gap between the band-edge and trap states is closely associated with ZnSe phonons that assist carrier trapping into defects in highly luminescent InP/ZnSe/ZnS QDs. These findings represent a striking departure from the generally accepted view of carrier trapping mechanism in QDs in the Marcus normal region, providing a step forward understanding how excitons in nanocrystals interact with traps, and offering valuable guidance for making highly efficient and stable InP-based QDs.


Assuntos
Pontos Quânticos , Luminescência , Sulfetos , Compostos de Zinco
20.
J Korean Neurosurg Soc ; 64(4): 644-664, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34185983

RESUMO

OBJECTIVE: Since the enactment of the Special Act on Korean Medical Residents, neurosurgeons working at training hospitals have been performing the duties of residents, in addition to their existing patient care responsibilities, which include surgery, education, and research. This study explores the relationships between work intensity, work-life balance, and burnout experienced by Korean neurosurgeons. METHODS: The participants (n=451) were neurosurgeons working at training hospitals throughout Republic of Korea. Data on socio-demographic characteristics (including objective and subjective work environment), work intensity, work-life balance, and burnout were gathered using self-report questionnaires completed between March 1 and December 20, 2019. The data were analyzed using descriptive statistics, independent samples t-tests, one-way analysis of variance, Pearson's correlations, and multiple regression analysis. IBM SPSS Statistics for Windows, version 25 (IBM Corp., Armonk, NY, USA) was used for the analyses. RESULTS: The work intensity, work-life balance, and burnout levels of neurosurgeons were 3.95, 3.57 (on a scale from 1 to 5) and 4.60 (on a scale from 1 to 7); and 280 (62.1%) of 451 neurosurgeons were found to be experiencing burnout. By controlling for the socio-demographic characteristics, the effects of work intensity and work-life balance on burnout were analyzed. Work intensity (B=0.314), work-life balance-family and leisure (B=0.216), work-life balance-growth (B=0.147), job stress (B=0.133), and satisfaction with human relationships (B=-0.069) were shown to be significant (all p<0.05), and they were found to affect burnout in the abovementioned order. The overall explanatory power was 58.3% (p<0.05), and the explanatory power with the addition of independent variables such as work intensity and work-life balance was 14.5% (p<0.05). CONCLUSION: This study showed that Korean neurosurgeons working at training hospitals experienced a high level of work intensity and job stress, and low work-life balance. Additionally, nearly half of the neurosurgeons were found to experience burnout related to factors such as work intensity, work-life balance, job stress, and satisfaction with human relationships. In particular, these factors seem to have deteriorated further after the implementation of the Special Act on Korean Medical Residents. These very high levels of burnout among Korean neurosurgeons who care for patients with both brain and spinal diseases may have a very important impact on patients' health. Therefore, it is recommended that the Korean Neurosurgical Society and the Korean government make efforts to improve the factors that affect burnout among Korean neurosurgeons.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...