ABSTRACT
Phosphor-converted white light-emitting diodes (WLEDs) have received significant attention; however, the leaked light from their blue InGaN chips has an undesirable effect on human health. Hence, it is necessary to develop red, green, and blue-emitting phosphors, which can be excited by an NUV chip instead of a blue chip. Herein, green-emitting ZnO:Cu2+ phosphors have been successfully synthesized by a simple and facile thermal diffusion method. The obtained powder shows a broad emission band peaking at 525 nm and a strong absorption peak at 377 nm. The ZnO:5%Cu2+ phosphor annealed at 800 °C in 2 hours revealed a lifetime of 0.57 ms, an activation energy of 0.212 eV, and the highest emission intensity with (x, y) CIE colour coordinates (0.3130, 0.5253). A WLED prototype has been fabricated by coating the ZnO:5%Cu2+ phosphor on an NUV 375 nm LED chip, where this coated phosphor shows a high quantum efficiency (QE) of 56.6%. This is, so far, the highest reported QE value for ZnO-based phosphors. These results suggest that the ZnO:Cu2+ phosphor could be an excellent candidate for NUV-pumped phosphor-converted WLED applications.
ABSTRACT
Microglandular adenosis (MGA) and atypical microglandular adenosis (AMGA) are intensely rare and distinctive forms of adenosis of the breast, usually occurring in middle-aged women. Carcinoma arising in MGA is an extremely rare subtype of breast carcinoma, and most reported cases are of invasive carcinoma. Ultrasound and magnetic resonance imaging are accurate imaging modalities for diagnosing these abnormalities. Our goal in this article was to report a rare instance of ductal carcinoma in situ (DCIS) arising from MGA and AMGA in a very young Vietnamese woman who presented with a palpable mass in her right breast for 1 month. During clinical examination and imaging, suspected lesions were found and categorized as BI-RADS 4a. The final histopathological findings confirmed DCIS arising from MGA/AMGA. In this patient, the disease was detected and managed early when the lesion was localized in the duct and there were no signs of invasive ductal carcinoma.
ABSTRACT
Objective: The study aimed to evaluate the role of magnetic resonance imaging (MRI) in differentiating between primary benign and malignant soft tissue tumors (STTs). Patients and Methods: The study was carried out on 110 patients with histopathological diagnoses of STTs. All patients underwent routine MRI before surgery/biopsy at Viet Duc University Hospital or Vietnam National Cancer Hospital, Hanoi, Vietnam, from January 2020 to October 2022. Data on preoperative MRI as well as the clinical features and pathological results of the patients were collected retrospectively. Univariate and multivariate linear regression were used to analyze the relationship between imaging, clinical parameters, and the ability to differentiate malignant from benign STTs. Results: Among 110 patients (59 men and 51 women), 66 had benign tumors and 44 had malignant tumors. The qualitative values that were significant in distinguishing between benign and malignant STTs were hypointensity on T1-weighted images (T1W; p<0.001), hypointensity on T2-weighted images (T2W; p=0.003), cysts (p=0.003)), necrosis (p<0.001), fibrosis (p=0.023), hemorrhage (p<0.001), lobulated margin (p<0.001), ill-defined border (p<0.001), peritumoral edema (p<0.001), vascular involvement (p<0.001), and heterogeneous enhancement (p<0.001). Regarding quantitative values, age (p=0.009), size (p<0.001), T1W signal quantification value (p=0.002), and T2W signal quantification value (p=0.007) showed statistically significant differences between benign and malignant tumors. Multivariate linear regression analysis showed that the combination of peritumoral edema and heterogeneous enhancement was the most valuable in the differential diagnosis of malignant tumors from benign tumors. Conclusion: MRI is valuable in discriminating between malignant and benign STTs. The presence of cysts, necrosis, hemorrhage, lobulated margin, ill-defined border, peritumoral edema, heterogeneous enhancement, vascular involvement, and T2W hypointensity is suggestive of malignant lesions, especially signs of peritumoral edema and heterogeneous enhancement. Advanced age and large tumor size are also suggestive of soft tissue sarcomas.
ABSTRACT
Objective: This study aimed to assess the predictive value of preoperative diffusion tensor imaging (DTI) data for surgical outcomes of patients with supratentorial glioma in the motor function area. Patients and Methods: This is a retrospective study of 43 patients receiving navigation-guided surgery for histopathologically demonstrated supratentorial glioma in the motor function area. All patients underwent preoperative 3 Tesla magnetic resonance imaging examinations with conventional and DTI sequences. Data on preoperative imaging and pre- and postoperative clinical characteristics of patients were retrospectively collected. Univariate and multivariate linear regressions were applied to analyze the relationships between preoperative parameters and pre- and postoperative muscle strength and the Karnofsky Performance Status (KPS) score. Results: Fourteen patients had low-grade gliomas and 29 had high-grade gliomas. Although the corticospinal tract (CST) score did not differ significantly between tumor grades, edema and deviation were common in low-grade gliomas (64.3%), while destroyed and infiltrated lesions were common in high-grade gliomas (58.6%). Muscle strength improved after surgery in the deviated tract group (40%) more than in the infiltrated tract group (33.3%). Two independent indices, preoperative muscle strength (p = 0.000) and glioma-to-CST distance (p = 0.001), were linearly related to postoperative muscle strength. The preoperative KPS score was the only indicator that affected the postoperative KPS score (p = 0.000). Conclusion: DTI should be considered in surgical management of supratentorial gliomas in the motor function area to determine the appropriate surgical strategy and predict the nature of the tumor and postoperative motor function.
ABSTRACT
BACKGROUND: Abdominal solid organ trauma accounts for 86.9% of all blunt abdominal trauma cases, among which 5%-25% of cases are associated with arterial injuries. Aim: In this study, we aimed to determine the characteristics and diagnostic functions of computed tomography (CT) scans during the diagnosis of arterial injuries, including active extravasation, pseudoaneurysm, and arteriovenous fistula associated with solid organ trauma compared with digital subtraction angiography (DSA). METHODS: From July 2019 to March 2020, a retrospective study was performed on 44 patients who presented with clinical manifestations of blunt abdominal injury and CT diagnosis of arterial injuries due to solid organ trauma, including active extravasation, pseudoaneurysm, and arteriovenous fistula, and later underwent DSA at Vietduc Hospital, in Hanoi, Vietnam. The features of arterial lesions on CT scan was described. Value of CT scan for the diagnosis of arterial injuries was analyzed compared to the DSA findings. RESULTS: There were 53 arterial lesions observed on CT scan including 15 active extravasations, 34 pseudoaneurysms, and 4 arteriovenous fistulas while 51 arterial lesions were observed on DSA including 15 active extravasations, 30 pseudoaneurysms, and 6 arteriovenous fistulas. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of active extravasation, pseudoaneurysm, and arteriovenous fistula on CT scan were 93.3%, 97.7%, 93.3%, 97.7% and 96.6% ; 90%, 75%, 79.4%, 87.5% and 82.8%; and 66.7%, 100%, 100%, 96.3% and 96.6%, respectively. CONCLUSIONS: Our study showed that CT scans had high sensitivity and specificity for the diagnosis of active extravasation; however, CT scans demonstrated low specificity for detecting pseudoaneurysm and low sensitivity for the diagnosis of arteriovenous fistula.
