Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Clin Cosmet Investig Dermatol ; 17: 649-652, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38505807

RESUMO

We describe a case involving a 19-year-old female with who presented with bilateral nipple-areola brown patches persisting for five years. The diagnosis of hyperkeratosis of the nipple and areola (HNA) was established through dermoscopy and histopathology. The findings highlight the value of dermoscopy in the diagnosis and differentiation of HNA.

2.
Clin Cosmet Investig Dermatol ; 17: 117-123, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38250638

RESUMO

Superficial Acral fibroma (SAF), also known as osteofibroma, is a rare fibromatous tumor primarily involving superficial soft tissues. Clinically, SAF typically manifests as a slow-growing, solitary, well-defined nodule or mass. Although these lesions are generally asymptomatic, some cases may present with associated pain, often linked to a history of trauma. SAF lesions commonly exhibit hemispherical, polypoid, or warty growths, with occasional occurrences of ulceration and bleeding.The majority of SAFs express CD34 and CD99, but in the two cases we report, there was diffuse expression of CD34 and focal positive expression of CD68. CD68 positivity suggests a propensity for tumor cells to metastasize to secondary sites. Notably, previously reported cases of single SAF did not display positive CD68 expression, indicating a potential association with other aggressive tumors. However, the current clinical and pathological manifestations do not clarify the diagnosis of additional malignant tumors. Consequently, regular postoperative monitoring of the patient from the aforementioned two cases is essential to detect the presence of other malignant tumors. The significance of CD68-positive expression in this case lies in its potential association with such tumors.

3.
Clin Cosmet Investig Dermatol ; 16: 2453-2456, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37705613

RESUMO

A 53-year-old male presented to the clinic for "bilateral temporal dark yellow plaques with pruritus for 8 years." The patient had bilateral temporal dark yellow plaques without obvious inducement 8 years ago and did not see doctors at that time. Five years ago, bilateral temporal skin lesions gradually increased and were accompanied by severe itching. On top of them, there were several blackheads and pimples with the size of needle tips up to the size of rice grains. After compression, lipid substances could be excreted and there was a clear odor. The patient sought medical attention at a local hospital, but the diagnosis and medication were unknown, and the symptoms did not improve. In the past month, due to the aggravation of skin lesions and itching that affected sleep, he visited the outpatient clinic of our hospital again. The patient was diagnosed with nodular elastoidosis with cysts and acne and was given 5% peroxybenzoyl gel and 0.1% tretinoin cream for topical use. After 2 weeks, the itching symptoms of the patient were significantly reduced.

4.
Clin Cosmet Investig Dermatol ; 16: 1857-1864, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37483472

RESUMO

We present the first case of coma bullae observed in a 67-year-old woman due to pressure and ischemia associated with brachioradial artery. A skin biopsy taken from the ulcer border revealed extensive loss of the epidermis, fibrosis of dermis, mild infiltration by lymphocytes and neutrophils, and necrosis of the focal eccrine ducts. CT angiography of the right upper limb showed a high origin of the radial artery, meanwhile both high originating radial artery and the anastomoses were tortuous and were of relatively small caliber. The diagnosis of coma bullae was made. After tissue debridement, the skin lesions gradually recovered, leaving atrophic scars.

5.
BMC Geriatr ; 23(1): 357, 2023 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-37291516

RESUMO

BACKGROUND: Myocardial injury post-stroke is a common sequela of acute stroke. Triglyceride-glucose index (TyG index), a valuable surrogate indicator of insulin resistance, has been suggested to be closely related to cardiovascular outcomes. However, it is unknown whether the TyG index is independently associated with a higher risk of myocardial injury post-stroke. We therefore investigated the longitudinal association between TyG index and risk of myocardial injury post-stroke in older patients with first-ever ischemic stroke and no prior cardiovascular comorbidities. METHODS: We included older patients with first-ever ischemic stroke and no prior cardiovascular comorbidities between January 2021 to December 2021. The individuals were stratified into low and high TyG index groups according to the optimal cutoff value with TyG index. We performed logistic regression analysis, propensity score matching (PSM) analysis, restricted cubic spline analysis, and subgroup analyses to explore the longitudinal association between TyG index and risk of myocardial injury post-stroke. RESULTS: We included 386 individuals with a median age of 69.8 years (interquartile range: 66.6, 75.3). The optimal TyG index cut-off for predicting myocardial injury post-stroke was 8.9 (sensitivity 67.8%; specificity 75.5%; area under curve 0.701). Multivariate logistic regression analysis revealed that the risk of genesis of myocardial injury post-stroke increased with elevated TyG index (odds ratio [OR], 2.333; 95% confidence interval [CI], 1.201-4.585; P = 0.013). Furthermore, all covariates were well balanced between the two groups. The longitudinal association between TyG index and myocardial injury post-stroke remained significantly robust (OR: 2.196; 95% CI: 1.416-3.478; P < 0.001) after PSM adjustment. CONCLUSION: Individuals with an elevated TyG index were more susceptible to having an increased risk of myocardial injury post-stroke. TyG index thus might be served as a complementary approach for optimized-for-risk stratification in older patients with first-ever ischemic stroke and no prior cardiovascular comorbidities.


Assuntos
AVC Isquêmico , Acidente Vascular Cerebral , Humanos , Idoso , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia , Progressão da Doença , Glucose , Triglicerídeos , Glicemia , Biomarcadores , Fatores de Risco , Medição de Risco
6.
Clin Cosmet Investig Dermatol ; 16: 1073-1077, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37123623

RESUMO

Purpose: We aimed to report a case of prurigo pigmentosa (PP) with blisters. Patients and Methods: A 21-year-old male patient presented to our hospital with erythema, papules, and blisters all over the front chest and back. Densely distributed round and oval edematous erythema was noted on the neck, front chest, and back of the patient. Histopathologic examination of the skin lesions (blisters) on the chest revealed epidermal cell hyperkeratosis. He was diagnosed with PP and was treated with oral minocycline. Results: After 1-week minocycline administration, the patient's itching was relieved, and the blisters dried up. His skin lesions recurred following self-withdrawal from the medication; subsequently, the patient was administered oral minocycline treatment again. After 1-month continuous oral treatment, the drug was discontinued. No recurrence of symptoms was noted. Conclusion: Oral minocycline is effective for the treatment of PP.

7.
Clin Cosmet Investig Dermatol ; 16: 1019-1023, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37089910

RESUMO

We describe a 39-year-old woman with a 1-month-old linear erythema diagnosed with cutaneous larva migrans by reflectance confocal microscopy (RCM). This case reveals that the great significance of diagnosing and treating cutaneous larva migrans (CLM) by RCM and dermoscopy, which might provide novel insights into dermatological clinical practice.

9.
Clin Cosmet Investig Dermatol ; 15: 2017-2020, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36172247

RESUMO

As scrotal simple lymphangioma is a rare benign proliferation of lymphatic vessels in the scrotum, a few reports were documented. A 68-year-old man gradually developed vesicles on the scrotum for ten years and easily ruptured due to friction. Physical examination showed diffuse millet-sized vesicles on the scrotum with milky white fluids and chyle-like exudates. Histopathological examination revealed proliferating and dilated lymphatic vessels with various sizes of lumens in the dermis. An immunohistochemical study showed positive staining for D2-40 and CD31. Therefore, the patient was diagnosed with scrotal lymphangioma and received carbon dioxide laser therapy. After the treatment, the vesicles markedly decreased, and no apparent exudates were observed. During one year of the follow-up, no relapse, scars, or other complications occurred.

10.
J Neuroinflammation ; 19(1): 176, 2022 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-35799259

RESUMO

BACKGROUND: Metabolic dysregulation and disruption of immune homeostasis have been widely associated with perioperative complications including perioperative ischemic stroke. Although immunometabolite S-2-hydroxyglutarate (S-2HG) is an emerging regulator of immune cells and thus triggers the immune response, it is unclear whether and how S-2HG elicits perioperative ischemic brain injury and exacerbates post-stroke cognitive dysfunction. METHODS: Perioperative ischemic stroke was induced by transient middle cerebral artery occlusion for 60 min in C57BL/6 mice 1 day after ileocecal resection. CD8+ T lymphocyte activation and invasion of the cerebrovascular compartment were measured using flow cytometry. Untargeted metabolomic profiling was performed to detect metabolic changes in sorted CD8+ T lymphocytes after ischemia. CD8+ T lymphocytes were transfected with lentivirus ex vivo to mobilize cell proliferation and differentiation before being transferred into recombination activating gene 1 (Rag1-/-) stroke mice. RESULTS: The perioperative stroke mice exhibit more severe cerebral ischemic injury and neurological dysfunction than the stroke-only mice. CD8+ T lymphocyte invasion of brain parenchyma and neurotoxicity augment cerebral ischemic injury in the perioperative stroke mice. CD8+ T lymphocyte depletion reverses exacerbated immune-mediated cerebral ischemic brain injury in perioperative stroke mice. Perioperative ischemic stroke triggers aberrant metabolic alterations in peripheral CD8+ T cells, in which S-2HG is more abundant. S-2HG alters CD8+ T lymphocyte proliferation and differentiation ex vivo and modulates the immune-mediated ischemic brain injury and post-stroke cognitive dysfunction by enhancing CD8+ T lymphocyte-mediated neurotoxicity. CONCLUSION: Our study establishes that S-2HG signaling-mediated activation and neurotoxicity of CD8+ T lymphocytes might exacerbate perioperative ischemic brain injury and may represent a promising immunotherapy target in perioperative ischemic stroke.


Assuntos
Lesões Encefálicas , Isquemia Encefálica , Disfunção Cognitiva , AVC Isquêmico , Acidente Vascular Cerebral , Animais , Encéfalo/metabolismo , Lesões Encefálicas/metabolismo , Isquemia Encefálica/metabolismo , Linfócitos T CD8-Positivos , Disfunção Cognitiva/metabolismo , Glutaratos , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/metabolismo , Camundongos , Camundongos Endogâmicos C57BL
11.
Front Aging Neurosci ; 14: 865244, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35431888

RESUMO

Objective: This study aimed to investigate the clinical prognostic values of the preoperative systemic-immune-inflammation index (SII) in older patients undergoing non-cardiac surgery, using perioperative ischemic stroke as the primary outcome. Methods: This retrospective cohort study included older patients who underwent non-cardiac surgery between January 2008 and August 2019. The patients were divided into SII < 583 and SII ≥ 583 group according to the optimal SII cut-off value. The outcome of interest was ischemic stroke within 30 days after surgery. Primary, sensitivity, and subgroup analyses were performed to confirm that preoperative SII qualifies as a promising, independent prognostic indicator. Propensity score matching (PSM) analysis was further applied to address the potential residual confounding effect of covariates to examine the robustness of our results. Results: Among the 40,670 included patients with a median age of 70 years (interquartile range: 67, 74), 237 (0.58%) experienced an ischemic stroke within 30 days after surgery. SII ≥ 583 was associated with an increased risk of perioperative ischemic stroke in multivariate regression analysis [odds ratio (OR), 1.843; 95% confidence interval (CI), 1.369-2.480; P < 0.001]. After PSM adjustment, all covariates were well balanced between the two groups. The correlation between the SII and perioperative ischemic stroke remained significantly robust (OR: 2.195; 95% CI: 1.574-3.106; P < 0.001) in the PSM analysis. Conclusion: Preoperative SII, which includes neutrophil, platelet, and lymphocyte counts obtained from routine blood analysis, was a potential prognostic biomarker for predicting perioperative ischemic stroke after non-cardiac surgery in elderly older patients. An elevated SII, based on an optimal cut-off value of 583, was an independent risk factor for perioperative ischemic stroke.

12.
Biometrics ; 78(1): 286-299, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-33270218

RESUMO

This article presents a new method for modelling collective movement in continuous time with behavioural switching, motivated by simultaneous tracking of wild or semi-domesticated animals. Each individual in the group is at times attracted to a unobserved leading point. However, the behavioural state of each individual can switch between 'following' and 'independent'. The 'following' movement is modelled through a linear stochastic differential equation, while the 'independent' movement is modelled as Brownian motion. The movement of the leading point is modelled either as an Ornstein-Uhlenbeck (OU) process or as Brownian motion (BM), which makes the whole system a higher-dimensional Ornstein-Uhlenbeck process, possibly an intrinsic non-stationary version. An inhomogeneous Kalman filter Markov chain Monte Carlo algorithm is developed to estimate the diffusion and switching parameters and the behaviour states of each individual at a given time point. The method successfully recovers the true behavioural states in simulated data sets , and is also applied to model a group of simultaneously tracked reindeer (Rangifer tarandus).


Assuntos
Movimento , Rena , Algoritmos , Animais , Cadeias de Markov , Método de Monte Carlo
14.
Clin Cosmet Investig Dermatol ; 14: 1029-1031, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34466011

RESUMO

Wells syndrome (WS), also known as eosinophilic cellulitis, is a rare inflammatory dermatosis of unknown etiology that typically presents with pruritic cellulitis-like plaques. The first line treatment options for WS are topical or systemic corticosteroids, however, the development of side effects of systemic corticosteroids usually led to a switch to the second line therapy. Here, we reported a rare case of facial Wells syndrome misdiagnosed with bacterial cellulitis. A 26-year-old female presented with a one-week history of erythematous, edematous and blushing plaques partially covered by bullae. A skin biopsy revealed diffuse infiltration of eosinophils in the entire dermis and "flame figures" compatible with WS. Initially, the patient was successfully treated with methylprednisolone. However, three month later, the disease relapsed. Because of weight gain and centripetal obesity, the patient refused to oral administration of methylprednisolone. Traditional Chinese Medicine tripterygium glycosides (TG) 60mg/day was prescribed and the lesions completely resolved after 4 weeks without any recurrence. Our case suggests that tripterygium glycosides may be a safe and effective treatment option for Wells syndrome.

15.
Front Aging Neurosci ; 13: 810050, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35087397

RESUMO

Objective: Diabetes mellitus (DM) has been critically associated with unfavorable outcomes in the general population. We aimed to investigate the association between type 2 DM and long-term survival outcomes for postoperative ischemic stroke in patients who underwent non-cardiac surgery. Research Design and Methods: This was a retrospective cohort study of patients with non-cardiac surgery who had suffered from postoperative ischemic stroke between January 2008 and August 2019. Diabetic individuals were included in postoperative ischemic stroke patients with the DM group. The outcome of interest was long-term overall survival (OS). We conducted propensity score matching (PSM) and inverse probability treatment weighting (IPTW) to adjust for baseline characteristic differences between groups. Multivariate Cox regression analysis with stepwise selection was used to calculate the adjusted hazard ratio (HR) of OS and type 2 DM. Results: During a median follow-up of 46.2 month [interquartile range (IQR), 21.1, 84.2], 200 of 408 patients (49.0%) died. The OS rates at 3, 5, and 10 years were significantly lower for postoperative ischemic stroke patients with DM than those without DM (3 years OS: 52.2 vs. 69.5%, p < 0.001; 5 years OS: 41.6 vs. 62.4%, p < 0.001; 10 years OS: 37.2 vs. 56.6%, p < 0.001). All covariates were between-group balanced after using PSM or IPTW. The postoperative ischemic stroke patients with type 2 DM had a shortened OS in primary analysis (HR: 1.947; 95% CI: 1.397-2.713; p < 0.001), PSM analysis (HR: 2.190; 95% CI: 1.354-3.540; p = 0.001), and IPTW analysis (HR: 2.551; 95% CI: 1.769-3.679; p < 0.001). Conclusion: Type 2 DM was associated with an unfavorable survival outcome for postoperative ischemic stroke in patients who underwent non-cardiac surgery. When postoperative ischemic stroke co-occurred with type 2 DM, the potential synergies would have multiplicative mortality risk. Further research to assess the adverse effects of type 2 DM on long-term survival may be warranted.

16.
World J Gastroenterol ; 25(34): 5185-5196, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31558866

RESUMO

BACKGROUND: Compared with traditional open surgery, laparoscopic surgery is preferred due to the advantages of less trauma, less pain, and faster recovery. Nevertheless, many patients still suffer from postoperative pain resulting from the surgical incision and associated tissue injury. Many researchers have reported methods to improve postoperative pain control, but there is not a simple and effective method that can be clinically adopted in a widespread manner. We designed this study to prove the hypothesis that application of ropivacaine in the port site and operative site in patients is an effective and convenient method which can decrease postoperative pain and accelerate recovery. AIM: To evaluate the effects of ropivacaine on pain control after laparoscopic hepatectomy and its contribution to patient recovery. METHODS: From May 2017 to November 2018, 146 patients undergoing laparoscopic hepatectomy were randomized to receive infiltration of either 7.5 mg/mL ropivacaine around the trocar insertions, incision, and cutting surface of the liver (with a gelatin sponge soaked with ropivacaine) at the end of surgery (ropivacaine group), or normal saline (5 mL) at the same sites at the end of surgery (control group). The degree of pain, nausea, vomiting, heart rate (HR), and blood pressure were collected. The length of postoperative hospitalization, complications, and the levels of stress hormones were also compared between the two groups. RESULTS: Compared with the control group, the ropivacaine group showed reduced postoperative pain at rest within 12 h (P < 0.05), and pain on movement was reduced within 48 h. The levels of epinephrine, norepinephrine, and cortisol at 24 and 48 h, HR, blood pressure, and cumulative sufentanil consumption in the ropivacaine group were significantly lower than those in the control group (P < 0.05). In the ropivacaine group, hospitalization after operation was shorter, but the difference was not statistically significant. There were no significant differences in postoperative nausea, vomiting, or other complications, including hydrothorax, ascites, peritonitis, flatulence, and venous thrombus (P > 0.05), although fewer patients in the ropivacaine group experienced these situations. CONCLUSION: Infiltration with ropivacaine in the abdominal wound and covering the cutting surface of the liver with a gelatin sponge soaked with ropivacaine significantly reduce postoperative pain and the consumption of sufentanil.


Assuntos
Analgesia/métodos , Anestésicos Locais/administração & dosagem , Hepatectomia/efeitos adversos , Laparoscopia/efeitos adversos , Dor Pós-Operatória/prevenção & controle , Ferida Cirúrgica/complicações , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hepatectomia/métodos , Humanos , Injeções Intralesionais , Cuidados Intraoperatórios/métodos , Laparoscopia/métodos , Masculino , Pessoa de Meia-Idade , Medição da Dor , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/etiologia , Ropivacaina/administração & dosagem , Tampões de Gaze Cirúrgicos , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
17.
ACS Appl Mater Interfaces ; 11(33): 30176-30184, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31343151

RESUMO

Organic-inorganic perovskite nanocrystals with excellent optoelectronic properties have been utilized in various applications, despite their stability issues. The perovskite materials are sensitive to environments such as polar solvents, moisture, and heat. Thus, they are not used for extrusion three-dimensional (3D) printing, as it is usually conducted in the ambient environment and requires heating to liquefy the printed materials. In this work, 11 thermoplastic polymers conventionally used for extrusion 3D printing were investigated to test their capability as protective encapsulation materials for perovskite nanocrystals. Three of them exhibited good protective properties, and one (polycaprolactone, PCL) of these three could be blended with perovskite nanocrystals to form perovskite nanocrystal-PCL composites, which were deformable and stretchable once heated. Because of the low melting point of PCL, the perovskite nanocrystals maintained their optical properties after 3D printing, and the printed objects were still having fluorescent behavior. Moreover, fluorescent micrometer-sized fibers based on the perovskite nanocrystal-PCL composites could also be simply prepared using cotton candy makers. Perovskite nanocrystal-PCL composite films with different emission wavelengths were incorporated with blue light-emitting diodes (LEDs) to realize white LEDs with Commission Internationale de l'Éclairage chromaticity coordinates of (0.33, 0.33).

18.
RSC Adv ; 9(19): 10584-10598, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-35515314

RESUMO

The electrical current leakage and stability are studied for solution-processed OLEDs with areas of 4.45 mm2, 3 × 3.2 cm2, and 6 × 11.5 cm2. The emission layer of the OLED has a ternary or binary mixed host with hole-transporting molecules tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), together with the electron-transporting molecule 2,7-bis(diphenylphosphoryl)-9,9'-spirobi[fluorene] (SPPO13). The phosphorescent emitters are Ir(mppy)3 for green and bis[4-(4-tert-butylphenyl)thieno[3,2-c]pyridine][N,N'-diisopropylbenamidinato]iridium(iii) (PR-02) for orange. Poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)] (TFB) is used as the hole transport layer and PEDOT:PSS is used as the hole injection layer. On top of the emission layer, CsF/Al is deposited by thermal evaporation as the cathode. All organic layers are deposited by blade coating and the initial current leaking defects can be avoided by careful control of the coating conditions. The detrimental burning point caused by a local current short developed after long-time operation can be avoided by reducing the operation voltage using a ternary mixed host. The operation voltage is only 4 V at 100 cd m-2 and 5 V at 250 cd m-2 for the green emitting device. Furthermore, the crystallization defect is reduced by the ternary host. For the orange emitting device, the binary host is good enough with an operating voltage of 5 V at 100 cd m-2. For an area as large as 6 × 11.5 cm2, the OLED shows good stability and there is no burning point after an operation of over 1600 hours.

19.
Chempluschem ; 84(9): 1375-1383, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31944041

RESUMO

The instability of the organic light-emitting diodes (OLEDs) during operation can be attributed to the existence of point defects on the organic layers. In this work, the effect of mixed-host emissive layer and the thermal annealing treatment were investigated to eliminate defects and to boost the device performance. The mixed-host system includes 4,4',4''-tri (9-carbazoyl) triphenylamine (TCTA) and 2,7-bis(diphenylphosphoryl)-9, 9'-spirobi[fluorene] (SPPO13). The mixed-host emissive layer with thermal annealing treatment showed low roughness and few pinholes, and the devices fabricated from this emissive layer exhibited high efficiencies, high stabilities, and long lifetimes. The red and orange-red OLEDs exhibited efficiencies of 13.9 cd/A and 24.35 cd/A, respectively. The longest half-lifetime (L0 =500 cd/m2 ) of the red and orange-red OLEDs were 158 h and 180 h, respectively. Efforts were made to solve problems in large-area coating and to reduce the number of defects on in organic layer. Large-active-area (active area=3 cm×4 cm) red phosphorescent OLEDs (PhOLEDs) devices were realized with very high current efficiency up to 9 cd/A.

20.
Dalton Trans ; 47(19): 6713-6721, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29708253

RESUMO

Optical thermometry based on up-conversion (UC) fluorescent intensity ratio (FIR) with 808 nm excitation is preferable in water-rich environments, and investigation of the ambiguous intrinsic influencing factors on host-dependent sensitivity is a prerequisite for the development of highly sensitive thermometry. Herein, MIn2O4:Nd3+/Yb3+/Er3+ (M = Ca, Sr, and Ba) microcrystals with low phonon energy are synthesized via a sol-gel method. Intense UC luminescence with tunable emission color from green to red is obtained by controlling the Yb3+ content, and the UC mechanisms and successive energy transfer of Nd3+ → Yb3+ → Er3+ are elaborated using lifetime measurements. The thermal sensing properties of the samples based on the thermally coupled levels (4S3/2/2H11/2) of Er3+ are assessed, and their sensitivities increase gradually with an increase in temperature and reach the maximum of about 0.0048, 0.0033 and 0.0058 K-1 at 490 K for M = Ca, Sr, and Ba, respectively. By analysing the host structure, site symmetry of M2+ ions and characteristics of the M-O bonds, it is proposed that the higher Ca-O bond covalency in CaIn2O4 leads to better sensitivity than SrIn2O4 with the same structure, and the optimal sensitivity in BaIn2O4 is mainly attributed to the specific local crystal field of the Ba2+ site with higher ligancy and longer chemical bonds. These results provide insight for the selection of appropriate matrix materials to achieve higher temperature detection sensitivity.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...