Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
Radiol Phys Technol ; 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38517669

RESUMO

This study investigates the feasibility of estimating the radioactivity of radiopharmaceuticals using shielded syringes. The radioactivities of 99mTc-MDP, 99mTc-HMDP, 99mTc-ECD, 99mTc-MAG3, and 123I-IMP were measured using a dose calibrator. Correlation coefficients and regression equations were obtained from the radioactivity in the shielded and unshielded syringes. 99mTc-MDP was also measured for residual radioactivity after the administration. The correlation coefficients of 99mTc-MDP, 99mTc-HMDP, 99mTc-ECD, 99mTc-MAG3, and 123I-IMP were rs = 0.9998, rs = 0.9997, rs = 0.9999, rs = 0.9998, and rs = 0.9888, respectively. The regression equations were y = 0.0364x + 0.0913, y = 0.0349x + 0.0273, y = 0.0343x - 0.0018, y = 0.0522x + 0.1215, and y = 0.0383x + 0.0058, respectively. The correlation coefficient for the residual radioactivity of 99mTc-MDP was rs = 0.9887 and the regression equation was y = 0.1505x + 0.0853. The radioactivity of 99mTc- and 123I-labeled radiopharmaceuticals in shielded syringes was accurately measured. It was suggested that the measuring shielded syringes could provide an estimate of the actual radioactivity.

2.
BMC Microbiol ; 24(1): 84, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38468206

RESUMO

BACKGROUND: Although the pathology of multiple chemical sensitivity (MCS) is unknown, the central nervous system is reportedly involved. The gut microbiota is important in modifying central nervous system diseases. However, the relationship between the gut microbiota and MCS remains unclear. This study aimed to identify gut microbiota variations associated with MCS using shotgun metagenomic sequencing of fecal samples. METHODS: We prospectively recruited 30 consecutive Japanese female patients with MCS and analyzed their gut microbiomes using shotgun metagenomic sequencing. The data were compared with metagenomic data obtained from 24 age- and sex-matched Japanese healthy controls (HC). RESULTS: We observed no significant difference in alpha and beta diversity of the gut microbiota between the MCS patients and HC. Focusing on the important changes in the literatures, at the genus level, Streptococcus, Veillonella, and Akkermansia were significantly more abundant in MCS patients than in HC (p < 0.01, p < 0.01, p = 0.01, respectively, fold change = 4.03, 1.53, 2.86, respectively). At the species level, Akkermansia muciniphila was significantly more abundant (p = 0.02, fold change = 3.3) and Faecalibacterium prausnitzii significantly less abundant in MCS patients than in HC (p = 0.03, fold change = 0.53). Functional analysis revealed that xylene and dioxin degradation pathways were significantly enriched (p < 0.01, p = 0.01, respectively, fold change = 1.54, 1.46, respectively), whereas pathways involved in amino acid metabolism and synthesis were significantly depleted in MCS (p < 0.01, fold change = 0.96). Pathways related to antimicrobial resistance, including the two-component system and cationic antimicrobial peptide resistance, were also significantly enriched in MCS (p < 0.01, p < 0.01, respectively, fold change = 1.1, 1.2, respectively). CONCLUSIONS: The gut microbiota of patients with MCS shows dysbiosis and alterations in bacterial functions related to exogenous chemicals and amino acid metabolism and synthesis. These findings may contribute to the further development of treatment for MCS. TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Clinical Trials Registry as UMIN000031031. The date of first trial registration: 28/01/2018.


Assuntos
Microbioma Gastrointestinal , Sensibilidade Química Múltipla , Humanos , Feminino , Japão , Fezes/microbiologia , Aminoácidos
4.
Inorg Chem ; 63(9): 4196-4203, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38377386

RESUMO

We report on a new organic conductor κ″-(ET)2Cu[N(CN)2]Br (κ″-Br), which is the first polymorph of an organic superconductor κ-(ET)2Cu[N(CN)2]Br (κ-Br), where ET denotes bis(ethylenedithio)tetrathiafulvalene. κ″-Br has a similar κ-type arrangement of ET molecules to κ-Br, but, in contrast to the orthorhombic κ-Br, which has ordered polyanion chains, presents a monoclinic crystal structure with disordered polymeric anion chains. To elucidate the electronic state of κ″-Br, we performed band calculations as well as transport, magnetic, and optical measurements. The calculated band dispersion, magnitude of electron correlation, and room-temperature optical conductivity spectra of κ″-Br were comparable to those of κ-Br. Despite these similarities, the κ″-Br salt exhibited a semiconducting behavior. The electron spin resonance and Raman spectroscopies indicated that there is neither magnetic nor charge order in κ″-Br, suggesting the occurrence of Anderson localization due to disordered anion layers.

5.
Radiol Phys Technol ; 17(1): 195-206, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38165579

RESUMO

Somatostatin receptor scintigraphy (SRS) is an essential examination for the diagnosis of neuroendocrine tumors (NETs). This study developed a method to individually optimize the display of whole-body SRS images using a deep convolutional neural network (DCNN) reconstructed by transfer learning of a DCNN constructed using Gallium-67 (67Ga) images. The initial DCNN was constructed using U-Net to optimize the display of 67Ga images (493 cases/986 images), and a DCNN with transposed weight coefficients was reconstructed for the optimization of whole-body SRS images (133 cases/266 images). A DCNN was constructed for each observer using reference display conditions estimated in advance. Furthermore, to eliminate information loss in the original image, a grayscale linear process is performed based on the DCNN output image to obtain the final linearly corrected DCNN (LcDCNN) image. To verify the usefulness of the proposed method, an observer study using a paired-comparison method was conducted on the original, reference, and LcDCNN images of 15 cases with 30 images. The paired comparison method showed that in most cases (29/30), the LcDCNN images were significantly superior to the original images in terms of display conditions. When comparing the LcDCNN and reference images, the number of LcDCNN and reference images that were superior to each other in the display condition was 17 and 13, respectively, and in both cases, 6 of these images showed statistically significant differences. The optimized SRS images obtained using the proposed method, while reflecting the observer's preference, were superior to the conventional manually adjusted images.


Assuntos
Redes Neurais de Computação , Receptores de Somatostatina , Diagnóstico por Computador/métodos , Tomografia Computadorizada por Raios X , Cintilografia
9.
Nihon Hoshasen Gijutsu Gakkai Zasshi ; 79(8): 802-809, 2023 Aug 20.
Artigo em Japonês | MEDLINE | ID: mdl-37357400

RESUMO

PURPOSE: The purpose of this study was to evaluate the residual radioactivity in the syringe and route of administration of a low fluid volume 99mTc-macro aggregated albumin (MAA) intended for pediatric nuclear medicine examinations. METHOD: We evaluated the residual characteristics, as the effect of elapsed time from drawing up of radiopharmaceuticals to plastic syringe to administration, and the effect of volume of 99mTcO4- solution to be labeled, the effect of rinsed times of plastic syringe, effect of dose of calculated by consensus guidelines for pediatric nuclear medicine and residual location in injection sets with 99mTc-MAA. Residual radioactivity was measured using planar images obtained by the gamma camera. RESULTS: Residual radioactivity rate of 99mTc-MAA, 99mTc-MAG3, 123I-IMP showed 41.3±1.6%, 14.4±0.6%, 14.6±2.0%, respectively. 99mTc-MAA clearly showed a higher residual rate. Residual radioactivity rate increased with the extension of the elapsed time, and reached a high value of 41.3% in 30 minutes. Residual radioactivity rate was dependent on the different volume of 99mTcO4- to be labeled (4.0 ml and 8.0 ml). Residual radioactivity rate did not change when the number of rinsed was more than one. Residual rate was around 40% at all doses of calculated by consensus guidelines for pediatric nuclear medicine. CONCLUSION: 99mTc-MAA showed the highest residual radioactivity rate among radiopharmaceuticals used in pediatric nuclear medicine examinations. The factor that most affected the residual radioactivity rate of 99mTc-MAA was the elapsed time from draw up to the plastic syringe to administration.


Assuntos
Medicina Nuclear , Radioatividade , Humanos , Criança , Compostos Radiofarmacêuticos , Seringas , Agregado de Albumina Marcado com Tecnécio Tc 99m , Albuminas , Plásticos
10.
Allergol Int ; 72(3): 428-436, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36997391

RESUMO

BACKGROUND: Although paranasal sinuses are one of the most representative organs affected by eosinophilic granulomatosis with polyangiitis (EGPA), they have not been studied sufficiently. The aim of this study was to compare computed tomography (CT) findings in paranasal sinuses of EGPA with those of other eosinophilic sinus diseases and elucidate the clinical relevance of their severity. METHODS: CT findings of paranasal sinuses in EGPA patients prior to therapeutic intervention (n = 30) were evaluated using the Lund-Mackay staging (LMS) system and compared with those of three control diseases [(NSAID-exacerbated respiratory disease (N-ERD), aspirin-tolerant asthma, and eosinophilic chronic rhinosinusitis without asthma (ECRS)]. We divided EGPA patients into three groups based on their LMS scores and examined their association with disease manifestation. RESULTS: Total scores of the LMS system in EGPA were significantly lower than those of N-ERD and ECRS without asthma. There was a large variation in total LMS scores in EGPA, suggesting considerable heterogeneity of their sinus lesions. Although EGPA with low LMS system scores showed only minor findings in maxillary and anterior ethmoid regions, those with high LMS system scores were characterized by high scores in the ostiomeatal complex. However, the frequencies of patients with a Five-Factor Score ≥2 and with cardiac involvement were significantly higher for EGPA with low LMS system scores. CONCLUSIONS: Although paranasal sinus lesions in EGPA were less severe than those of other eosinophilic sinus diseases, their milder CT findings may be associated with a higher frequency of extra-respiratory organ involvement.


Assuntos
Asma , Síndrome de Churg-Strauss , Granulomatose com Poliangiite , Seios Paranasais , Humanos , Granulomatose com Poliangiite/diagnóstico por imagem , Granulomatose com Poliangiite/complicações , Síndrome de Churg-Strauss/diagnóstico por imagem , Síndrome de Churg-Strauss/tratamento farmacológico , Relevância Clínica , Seios Paranasais/diagnóstico por imagem , Seios Paranasais/patologia , Asma/diagnóstico por imagem , Asma/complicações , Tomografia Computadorizada por Raios X , Tomografia
11.
Allergol Int ; 72(2): 252-261, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36371246

RESUMO

BACKGROUND: Frailty is a geriatric syndrome of age-related physiological decline, which is associated with higher mortality and decreased healthy life expectancy, and muscle weakness is one of the presentations of frailty. We investigated an association between lifetime oral corticosteroid (OCS) exposure with frailty and muscle weakness among elderly patients with asthma. METHODS: We studied 203 consecutive elderly outpatients with asthma aged ≥60 years old. They were classified into three groups according to their cumulative lifetime OCS dose (lifetime non-users, lower-dose users, and higher-dose users), which was retrospectively estimated from the response to a structured questionnaire. The prevalence of frailty determined by the Kihon Checklist was compared between the three groups. Hand-grip strength, and lean mass index were also measured as markers of muscle strength. RESULTS: Thirty-seven percent of the patients studied were considered frail. Higher cumulative lifetime OCS exposure was associated with a significantly higher prevalence of frailty (33% in lifetime non-users, 59% in lower-dose users, and 68% in higher-dose users; P for trend <0.005). This was also associated with lower hand-grip strength in both sexes (P for trend; 0.012 in men, and 0.020 in women), and lower lean mass index in men (P for trend 0.002). However, current doses of OCS were not significantly associated with these outcomes. CONCLUSIONS: Cumulative lifetime OCS exposure was associated with a higher prevalence of frailty and muscle weakness. These findings emphasize the importance of minimizing lifetime OCS exposure for the prolongation of healthy life expectancy in patients with asthma.


Assuntos
Asma , Fragilidade , Idoso , Masculino , Humanos , Feminino , Pessoa de Meia-Idade , Fragilidade/epidemiologia , Idoso Fragilizado , Estudos Retrospectivos , Avaliação Geriátrica , Debilidade Muscular/epidemiologia , Asma/tratamento farmacológico , Asma/epidemiologia , Corticosteroides/efeitos adversos
12.
iScience ; 25(11): 105404, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36439986

RESUMO

Endogenous humoral factors that link systemic and/or local insulin demand to pancreatic ß-cells have not been identified. Here, we demonstrated that T-cadherin, a unique glycosylphosphatidylinositol-anchored cadherin primarily expressed in vascular endothelial cells and cardiac and skeletal muscle cells, but not in pancreatic ß-cells, was secreted as soluble forms and was important for ß-cell proliferation. Cdh13 (T-cadherin) knockout mice exhibited impaired glucose handling due to attenuated ß-cell proliferation under high-fat diet conditions. The gene expression analyses indicated the impairment in cell cycle and Notch signaling in the islets of T-cadherin knockout mice under high-fat diet conditions. In streptozotocin-induced diabetes, the replacement of soluble T-cadherin improved ß-cell mass and blood glucose levels in T-cadherin knockout mice. Recombinant soluble T-cadherin upregulated Notch signaling in cultured murine islets. We concluded that soluble T-cadherin could work as an endogenous humoral factor whose signaling pathways including Notch signaling regulate ß-cell proliferation under diabetic conditions in mice.

13.
Nihon Yakurigaku Zasshi ; 157(5): 293-298, 2022.
Artigo em Japonês | MEDLINE | ID: mdl-36047138

RESUMO

Asthma therapy in general has improved a lot in recent years, but it is still a major problem that severe asthma, which accounts for 10 to 20%, still suffers from strong symptoms on a daily basis despite all therapeutic agents used in combination. American SARP and European ENFUMOSA started in 2000 to advance pathophysiological insights of severe asthma. Clinical usage of antibodies and inhibitors against IgE, TNF, IL-5, IL-4, IL-13, and TSLP are also accumulating. Some of these molecular-targeted drugs improve respiratory function and reduce acute exacerbations in patients with severe asthma. Until now, cytokines have been assumed to be involved in chronic inflammation, but it is also interesting to elucidate the pathways of how cytokines are involved in respiratory function and acute exacerbations. We registered approximately 100 steroid-dependent asthma patients in Japan. Although long-lasting poor control of the disease was considered the cause of severe asthma in the past, steroid dependence in one third of the cases occurred within 2-3 years after the onset. Steroid resistance seems a key process from the early stage of the disease. Steroid resistance of T cell level was induced by extracellular co-stimulation and cytokine signals. The inhibition may improve steroid sensitivity and treat steroid-resistant asthma. Therefore, we established a steroid-resistant asthma model for the first time by transferring steroid resistant T cell clones, and analyzed the steroid sensitivity recovery effect of CTLA4-Ig. In addition, a multicenter, double-blind, placebo-controlled exploratory trial was performed as a POC study investigating the efficacy of abatacept in treatment-resistant severe asthma. Elucidation of the pathophysiology and mechanism by which steroids do not work is expected to be a breakthrough for the prevention and treatment of severe asthma.


Assuntos
Asma , Citocinas , Método Duplo-Cego , Humanos , Japão , Esteroides/uso terapêutico
14.
Diabetologia ; 65(7): 1185-1197, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35511238

RESUMO

AIMS/HYPOTHESIS: Immunomodulators blocking cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) have improved the treatment of a broad spectrum of cancers. These immune checkpoint inhibitors (ICIs) reactivate the immune system against tumour cells but can also trigger autoimmune side effects, including type 1 diabetes. Mesenchymal stem cell (MSC) therapy is the most prevalent cell therapy, with tissue-regenerating, anti-fibrosis and immunomodulatory functions provided by the secretome of the cells. Here, we examined whether systemic MSC treatment could prevent the development of type 1 diabetes in a NOD mouse model. METHODS: The purified PD-L1 monoclonal antibody was administered to induce diabetes in male NOD mice which normally do not develop diabetes. Human adipose-derived MSCs were administered by tail vein injections. T cells, macrophages and monocyte-derived macrophages expressing C-X-C motif chemokine ligand 9 (CXCL9) in pancreatic sections of NOD mice and a cancer patient who developed diabetes following the ICI treatments were analysed by immunofluorescence. Tissue localisation of the injected MSCs, plasma exosome levels and plasma cytokine profiles were also investigated. RESULTS: PD-1/PD-L1 blockade induced diabetes in 16 of 25 (64%) NOD mice which received anti-PD-L1 mAb without hMSCs [MSC(-)], whereas MSC administration decreased the incidence to four of 21 (19%) NOD mice which received anti-PD-L1 mAb and hMSCs [MSC(+)]. The PD-1/PD-L1 blockade significantly increased the area of CD3-positive T cells (6.2-fold) and macrophage-2 (Mac-2) antigen (2.5-fold)- and CXCL9 (40.3-fold)-positive macrophages in the islets. MSCs significantly reduced T cell (45%) and CXCL9-positive macrophage (67%) accumulation in the islets and the occurrence of diabetes. The insulin content (1.9-fold) and islet beta cell area (2.7-fold) were also improved by MSCs. T cells and CXCL9-positive macrophages infiltrated into the intricate gaps between the beta cells in the islets by PD-1/PD-L1 blockade. Such immune cell infiltration was largely prevented by MSCs. The most striking difference was observed in the CXCL9-positive macrophages, which normally did not reside in the beta cell region in the islets but abundantly accumulated in this area after PD-1/PD-L1 blockade and were prevented by MSCs. The CXCL9-positive macrophages were also observed in the islets of a cancer patient who developed diabetes following the administration of ICIs but few CXCL9-positive macrophages were observed in a control patient. Mechanistically, the injected MSCs accumulated in the lung but not in the pancreas and strongly increased plasma exosome levels and changed plasma cytokine profiles. CONCLUSIONS/INTERPRETATION: Our results suggest that MSCs can prevent the incidence of diabetes associated with immune checkpoint cancer therapy and may be worth further consideration for new adjuvant cell therapy.


Assuntos
Diabetes Mellitus Tipo 1 , Células-Tronco Mesenquimais , Neoplasias , Animais , Anticorpos Monoclonais , Antígeno B7-H1/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Humanos , Inibidores de Checkpoint Imunológico , Masculino , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Neoplasias/metabolismo , Receptor de Morte Celular Programada 1/metabolismo
15.
Chem Commun (Camb) ; 58(24): 3893-3896, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35226032

RESUMO

Multiparameter screening of reductive carboxylation in an electrochemical flow microreactor was performed using a Bayesian optimization (BO) strategy. The developed algorithm features a constraint on passed charge for the electrochemical reaction, which led to suitable conditions being instantaneously found for the desired reaction. Analysis of the BO-suggested conditions underscored the physicochemical validity.

16.
Mod Rheumatol ; 32(2): 387-395, 2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-34910206

RESUMO

OBJECTIVE: To assess the effectiveness of low-dose mepolizumab as an add-on therapy for treating peripheral neurological symptoms in eosinophilic granulomatosis with polyangiitis (EGPA). METHODS: We prospectively studied 13 EGPA patients with conventional treatment-resistant peripheral neuropathy. Their symptoms (pain, numbness, and muscle weakness) were assessed on a visual analogue scale (VAS) before and after 12 months of mepolizumab therapy (100 mg every 4 weeks). Peripheral eosinophil levels and several biomarkers including urinary levels of eosinophil-derived neurotoxin (EDN) were measured before and after therapy. RESULTS: VAS scores for pain and numbness significantly improved after 12 months of mepolizumab therapy (from 67.0 to 48.0, P = 0.012, and from 67.0 to 51.0, P = 0.017, respectively). However, the VAS score for muscle weakness did not improve (P = 0.36). There were significant correlations between treatment-related changes in urinary EDN levels from baseline to 6 months later and percent changes in the VAS scores of pain and numbness (r = 0.75, P = 0.020; r = 0.88, P = 0.002). CONCLUSIONS: Treatment-resistant peripheral neuropathy in EGPA was significantly improved by low-dose mepolizumab, and effectiveness was correlated with decreased urinary EDN. Because the possibility of a placebo effect cannot be formally excluded, placebo-controlled studies will be required in the future.


Assuntos
Síndrome de Churg-Strauss , Granulomatose com Poliangiite , Doenças do Sistema Nervoso Periférico , Anticorpos Monoclonais Humanizados/uso terapêutico , Síndrome de Churg-Strauss/tratamento farmacológico , Granulomatose com Poliangiite/tratamento farmacológico , Humanos , Doenças do Sistema Nervoso Periférico/complicações , Doenças do Sistema Nervoso Periférico/tratamento farmacológico
17.
Allergol Int ; 71(1): 103-108, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34511312

RESUMO

BACKGROUND: Chronic spontaneous urticaria (CSU) is a common mast cell-driven disease, presenting with wheals, angioedema, or both. Sleep-disordered breathing (SDB) is also a common condition and contributes to various diseases by causing chronic inflammation. Recent studies have suggested an association between CSU and SDB. METHODS: To determine the association between the severity of SDB and that of CSU, we studied consecutive patients with CSU who visited the Sagamihara National Hospital allergy department or dermatology department between April 1 and October 31, 2018. The severity of CSU and SDB was evaluated based on the urticaria activity score 7 (UAS7) and peripheral arterial tone apnea-hypopnea index (pAHI) derived from out-of-center sleep testing (OCST) findings, respectively; their correlation was examined. RESULTS: Of the 37 patients studied, 19 had symptom-free-to-mild CSU (UAS7 ≤15) and 18 had moderate-to-severe CSU (UAS7 ≥16). The pAHI in the latter group was significantly higher than that in the former group (18 vs. 4.2, p = 0.001). In multivariate logistic analysis, moderate-to-severe SDB (pAHI ≥15) was significantly associated with moderate-to-severe CSU even after adjusting for the BMI (adjusted odds ratio 22 [95% confidence interval, 1.7-285]). CONCLUSIONS: The severity of SDB is correlated with that of CSU independently of the BMI. Physicians should consider comorbid SDB when treating patients with CSU.


Assuntos
Urticária Crônica/complicações , Síndromes da Apneia do Sono/congênito , Adulto , Causalidade , Comorbidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Síndromes da Apneia do Sono/diagnóstico
18.
Artigo em Japonês | MEDLINE | ID: mdl-34544916

RESUMO

PURPOSE: The purpose of this study was to evaluate the best phantom for calculating the becquerel calibration factor (BCF) and correction method to obtain the improvement of standardized uptake value (SUV) accuracy in both single photon emission computed tomography (SPECT) and SPECT/CT. METHOD: A SPECT/CT scanner was used in this study. BCFs were calculated using four phantoms with different cross sections including National Electrical Manufacturers Association International Electrotechnical Commission body phantom (NEMA IEC body phantom) filled with 99mTcO4-, and five correction methods were used for reconstruction. SUVs were calculated by the NEMA IEC body phantom and pediatric phantom in house with these BCFs. We then measured SUVmean in the background region of the NEMA IEC body phantom, SUVmax and SUVpeak of the 37-mm-diameter sphere. RESULTS: In the SPECT scanner, SUVmean and SUVmax measured 1.04 and 4.02, respectively, in the case of BCF calculation and SUV measurement using NEMA IEC body phantoms without corrections. In the SPECT/CT scanner, SUVmean with CT attenuation correction (AC) was in agreement with the theoretical values using each phantom. SUVmax showed the same trend. CONCLUSION: In the SPECT scanner, it is possible to obtain a highly accurate SUV by using a phantom that matches the size of the subject for BCF calculation and without correction. In the SPECT/CT scanner, highly accurate SUVs can be obtained by using CT-based attenuation correction, and these values do not depend on the size of the BCF calculation phantom.


Assuntos
Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X , Calibragem , Criança , Humanos , Imagens de Fantasmas
19.
ACS Appl Mater Interfaces ; 13(27): 31928-31933, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34192877

RESUMO

Molecule-based ferroelectrics has attracted much attention because of its advantages, such as flexibility, light weight, and low environmental load. In the present work, we examined an organic metal|insulator|semiconductor|insulator|metal (MISIM) device structure to stabilize the interfacial polarization in the S layer and to induce polarization hysteresis even without bulk ferroelectrics. The MISIM devices with I = parylene C and S = TMB (=3,3',5,5'-tetramethylbenzidine)-TCNQ (=tetracyanoquinodimethane) exhibited hysteresis loops in the polarization-voltage (P-V) curves not only at room temperature but also over a wide temperature range down to 80 K. The presence of polarization hysteresis for MISIM devices was theoretically confirmed by an electrostatic model, which also explained the observed thickness dependence of the I layers on the P-V curves. Polarization hysteresis curves were also obtained in MISIM devices using typical organic semiconductors (ZnPc, C60, and TCNQ) as the S layer, demonstrating the versatility of the interfacial polarization mechanism.

20.
J Org Chem ; 86(22): 15953-15960, 2021 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-34152747

RESUMO

The synthesis of α-amino acids was carried out in a continuous flow system. In this system, aldimines were efficiently generated in situ via the dehydration-condensation of aldehydes with anilines in a desiccant bed column filled with 4 Å molecular sieves desiccant, followed by reaction with CO2 in an electrochemical flow microreactor to afford the α-amino acids in high to moderate yields. The present system can provide α-amino acids without using stoichiometric amounts of metal reagents or highly toxic cyanide reagents.


Assuntos
Aldeídos , Aminoácidos , Indicadores e Reagentes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...