Improved light extraction efficiency of AlGaN deep-ultraviolet light emitting diodes combining Ag-nanodots/Al reflective electrode with highly transparent p-type layer

Enhancement of light extraction efficiency (LEE) of AlGaN-based deep-ultraviolet (DUV) light emitting diodes (LEDs) has been attempted by adopting Ag-nanodots/Al reflective electrodes on a highly transparent complex p-type layer. By thinning the p-GaN to several nm, highly DUV transparent p-type layer is achieved, making it meaningful for the application of reflective electrodes composed of Ag-nanodots and Al film to allow most light emitted upward to be reflected back to the sapphire side. By this approach, the maximum light output power and external quantum efficiency of the DUV-LEDs with optimized Ag nanodots/Al electrodes are severally increased by 52% and 58%, respectively, compared to those with traditional Ni/Au electrodes when the current is below 200 mA.

[Clinicopathological features of myeloid sarcoma and DLBCL in the breast: a comparative study]

Objective: To study the clinicopathological features, diagnosis and differential diagnosis of myeloid sarcoma of the breast. Methods: Ten cases of myeloid sarcoma (MS) and 19 cases of diffuse large B cell lymphoma (DLBCL) of the breast were selected from Peking University People's Hospital from February 2005 to September 2019. The cases were evaluated by microscopy and immunohistochemistry basing on WHO classification (2008 and 2017). Results: For the 10 cases of MS, the mean and median age was 33.8 and 31 years (range 23 to 47 years) respectively. All patients presented with breast masses; six presented with B symptoms (6/10); and LDH level was elevated in four patients. The largest tumor dimension was 1.0 to 5.3 cm (mean 2.7 cm). All 10 patients had history of acute myeloid leukemia (AML), and in one patient, the AML occurred after chemotherapy for hydatidiform mole. One case was classified as M0, four were M2, two were M4 and three were M5. For the AML, all patients received chemotherapy and nine were treated by allogeneic hematopoietic stem cell transplant (allo-HSCT) and the breast masses occurred4 months to 2 years post-transplant. Using Ann Arbor staging, five cases were stage Ⅰ, three were stage Ⅱ, and 2 were stage Ⅳ. The MS was found in the left breast (two cases); right breast (three cases) and both breasts (five cases). Lymphocyte in peripheral blood, B symptom and site of lesion had statistical significance between myeloid sarcoma and DLBCL(P<0.05). The tumor cells were primitive, expressing MPO, CD43, CD117, etc. All ten patients had follow-up information, and the median survival period was 14.4 months (range 1 to 50 months). Seven patients died. The prognosis of patients with MS was worse than DLBCL(P=0.002). Conclusions: The clinical history, pathologic morphology, immunophenotyping and molecular studies are very important for diagnosing MS tumors in the breast, and MS may occur after allo-HSCT for AML. Tumor resection, chemotherapy, radiotherapy and donor lymphocyte infusion are recommended for treatment. The prognosis is poor.

Greatly enhanced performance of AlGaN-based deep ultraviolet light emitting diodes by introducing a polarization modulated electron blocking layer

Carrier transport in AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) with the wavelength of 273 nm has been investigated by introducing polarization modulated electron blocking layer (EBL) that adopts an Al composition and thickness graded multiple quantum barriers (MQB) structure. The experimental result shows that the maximum light output power and external quantum efficiency for the proposed structure at the current of 250 mA are 9.6 mW and 1.03% respectively, severally increasing by 405% and 249% compared to traditional one, meanwhile, the efficiency droop at 250 mA is also dramatically reduced from 42.2% to 16.6%. Further simulation analysis indicates that this graded MQB-EBL enhances the potential barrier height for electrons and meanwhile reduces that for holes, hence effectively suppresses the electron leakage, and at the same time significantly improves the hole injection efficiency. As a result, the whole performance of the LED with the proposed MQB-EBL is dramatically improved.

Influence of Hydrostatic Pressure on the Corrosion Behavior of Superhydrophobic Surfaces on Bare and Oxidized Aluminum Substrates

It is generally recognized that superhydrophobic surfaces in water may be used for corrosion resistance due to the entrapped air in the solid/liquid interface and could find potential applications in the protection of ship hull. For a superhydrophobic surface, as its immersion depth into water increases, the resultant hydrostatic pressure is also increased, and the entrapped air can be squeezed out much more easily. It is therefore predicted that high hydrostatic pressure would cause an unexpected decrease in corrosion resistance for the vessels in deep water (e.g., submarines) because of the unstable entrapped air. In this work, in order to clarify the role of hydrostatic pressure in the corrosion behavior of superhydrophobic surfaces, two typical superhydrophobic surfaces (SHSs) were prepared on bare and oxidized aluminum substrates, respectively, and then were immersed into the NaCl aqueous solutions with different depths of ∼0 cm (hydrostatic pressure ∼0 kPa), 10 cm (1 kPa), and 150 cm (15 kPa). It was found out for the SHSs on the oxidized Al, as the hydrostatic pressure increased, the corrosion behavior became severe. However, for the SHSs on the bare Al, their corrosion behavior was complex due to hydrostatic pressure. It was found that the corrosion resistance under 1 kPa was the highest. Further mechanism analysis revealed that this alleviated corrosion behavior under 1 kPa resulted from suppressing the oxygen diffusion through the liquid and reducing the subsequent corrosion rate as compared with 0 kPa, whereas the relatively low hydrostatic pressure (HP) could stabilize the entrapped air and hence enhance the corrosion resistance, compared with 15 kPa. The present study therefore provided a fundamental understanding for the applications of SHSs to prevent the corrosion, especially for various vessels in deep water.

[Analysis of proliferative lesions of haematopoietic and lymphoid tissue in the female productive tract]

Objective: To study the clinicopathologic features, diagnosis and differential diagnosis of tumors of haematopoietic and lymphoid tissue in the female productive tract. Methods: Eleven cases of myeloid sarcoma and leukemia, 9 of non Hodgkin lymphoma (NHL) , 13 of cervical lymphoma-like lesions were selected from Peking University People's Hospital from January 2006 to August 2017. According to WHO classification of tumors of haematopoietic and lymphoid tissues (2008) and updated classification(2016), the cases were studied by microscopy, immunohistochemistry and in situ hybridization. Results: In 20 cases of tumors of haematopoietic and lymphoid tissue, the mean and median age was 48.5 and 56 years old (range: 16-77 years old) . In cases of lymphoma-like lesion of uterine cervix, the mean and median age was 45.9 and 48 years old (range: 23-62 years old) . The patients with neoplasm present as fever, fatigue, hypogastralgia, colporrhagia and mass etc. Eight cases had history of acute myeloid leukemia, and 3 had myeloid leukemia while pregnancy. One case of chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) had history of ovary small cell carcinoma and high grade serous carcinoma resected with chemotherapy. One case of diffuse large B cell lymphoma (DLBCL) had history of renal transplantation. Lactic dehydrogenase (LDH) was elevated in 9 cases (9/18) . The cases of lymphoma-like lesion present as contact bleeding in most cases and all located in cervix. Four cases of neoplasm located in vulva, 1 in vagina, 4 in cervix, 4 in uterine corpus, 8 in ovary and 2 in placenta. Clinical staging of NHL: 4 case was stageⅠ, 1 case of stageⅢ, and 4 cases of stage Ⅳ. Pathological morphology: 9 cases were myeloid sarcoma, 2 cases were placenta invaded by myeloid leukemia. Six cases were DLBCL, and 1 case was CLL/SLL, 1 case was mucosa associated lymphoid tissuse lymphoma (MALToma) , and 1 case was anaplastic large cell lymphoma. Resected mass, chemotherapy was performed in tumors of haematopoietic and lymphoid tissue. Five cases of myeloid sarcoma and 2 of NHL died. In 13 cases of lymphoma-like lesion of uterine cervix, the general condition was good as following up. Conclusions: The clinical history, pathological morphology and immunohistochemistry are very important for diagnosing tumors of haematopoietic and lymphoid tissue in the female productive tract. Resection with chemotherapy is recommended in treatment. The prognosis of lymphoma-like lesion of uterine cervix is good, and should be differentiated from lymphoma.

[Tumors of lymphoid and hematopoietic tissue of spleen: a clinicopathologic analysis of 53 cases]

Objective: To study the clinicopathologic features, diagnosis and differential diagnosis of the tumors of lymphoidand hematopoietic tissue of the spleen(TLTS). Methods: Fifty-three cases of TLTS were selected from the pathologic files from Peking University People's Hospital from April 2002 to April 2017. According to WHO classification of tumors of hematopoietic and lymphoid tissues (2008) and its updated classification (2016), the cases were studied by microscopy, immunohistochemistry and in situ hybridization, combined with the bone marrow biopsy and clinical examination. Results: In 53 cases of TLTS, the male to female ratio was 3.4∶1.0; the mean age was 55.4 years (range 21-76 years), and all patients presented with variable degree of splenomegaly. Laboratory examination showed increased percentage of lymphocyte in peripheral blood in 22 cases, and elevated serum LDH level in 24 cases. Abnormal blood counts were seen in 26 cases pre-operatively, in which 22 cases showed complete or partial correction of these abnormalities post-operatively (84.6%, 22/26). The clinical symptoms included abdominal pain or distension, fatigue, fever, and weight loss, etc. Seventeen cases presented with lymphadenopathy of abdomen or other sites. Bone marrow biopsy was performed in 30 cases, and 19 cases were involved by tumor (63.3%). Of all 53 cases, 43 were diagnosed as primary splenic lymphoma (PSL), and the remaining 10 cases as secondary TLTS. According to Ann Arbor staging, 14 cases were stages Ⅰ or Ⅱ, 6 were stage Ⅲ and 28 were stage Ⅳ. By histopathologic classification, 43 cases of PSL were splenic B-cell marginal zone lymphoma (SMZL; 48.8%, 21/43), diffuse large B cell lymphoma (DLBCL; 23.3%, 10/43), splenic diffuse red pulp small B-cell lymphoma (11.6%, 5/43), mantle cell lymphoma (9.3%, 4/43), follicular lymphoma (4.7%, 2/43), and composite lymphoma (CL, DLBCL and classical Hodgkin lymphoma; 2.3%, 1/43). The remaining 10 cases were chronic lymphocytic leukaemia/small lymphocytic lymphoma (4 cases), hairy cell leukaemia (1 case), hepatosplenic T-cell lymphoma (HSTL; 5 cases), with lesions in other sites. Of the 53 cases of TLTS, 47 were B cell neoplasm (88.7%, 47/53), and the T cell neoplasms were all HSTL(5 cases, 9.4%, 5/53), 1 case was composite lymphoma. In 11 cases of TLTS, EBER in situ hybridization was performed and all cases were negative. Forty eight cases had follow-up data, and the median survival period was 17.0 months(range: 1-96 months). The survival of patients with SMZL and DLBCL were 25.7 and 18.6 months respectively. Thirteen patients died (27.1%, 13/48). The prognosis of those with elevated LDH level, high clinical stage, B symptoms and older than 60 years of age was worse. And the prognosis of DLBCL was worse than that of SMZL. There was no statistically significant difference between these factors and prognosis (P>0.05). Conclusions: Most TLTS cases present with splenomegaly and abnormal blood counts, and complete or partial remission of blood counts isseen after splenectomy. The most common pathologic types of TLTS are SMZL and DLBCL. Definite diagnosis of TLTS could be made by combining clinical features, histopathology, immunophenotype, genetics, bone marrow biopsy and laboratory examination.

[Analysis of epidermal growth factor receptor mutations and its clinico-pathologic characteristics of the primary lung adenocarcinoma in Xinjiang Uighur Autonomous Region]

OBJECTIVE

To clarify the relationship between epidermal growth factor receptor (EGFR) mutations and the clinicopathologic features of primary lung adenocarcinomas in Xinjiang.

METHODS

The mutations of EGFR gene at exons 18-21 in 59 cases (including 15 cases of Uighur and 44 cases of Han) of lung adenocarcinoma tissues, which were obtained from surgical resection, were detected by amplification refractory mutation system (ARMS) method. And the relationships among mutations, race and clinicopathologic features were analyzed.

RESULTS

The frequencies of EGFR mutations in lung adenocarcinoma were 20% for Uighur, which was lower than that in Han (54.5%), P<0.05. The deletion mutations at exon 19 were seen in 2 of 15 Uighur cases and 9 of 44 Han cases. EGFR mutations were present, including exon 21 L858R in one Uighur case and 12 Han cases, exon 18 G719X in two of 44 cases of Han, exon 21 L861Q in one of them. On histological type, the frequencies of EGFR mutation in alveolar predominant adenocarcinoma was 71% (22/31), which was higher than both that in solid predominant and mucinous carcinoma ( 6.7%, 20% respectively). According to statistic analysis, EGFR mutations were without correlation with the patient's gender, age, location, gross type, smoking status and lymph node metastasis(P>0.05). EGFR mutation was more frequent in well-differentiated cancer, mainly in acinar carcinoma, while poorly differentiated adenocarcinoma and mucous adenocarcinoma were lower.

CONCLUSION

There was a difference of EGFR mutation in primary lung adenocarcinoma between Uighur and Han in Xinjiang, perhaps reflecting ethnic genetic variation, which is worth further analyzing. EGFR mutation was commonly detected in well or middle differentiated adenocarcinoma, mainly in acinar carcinoma.

[Analysis of epidermal growth factor receptor mutations and its clinico-pathologic characteristics of the primary lung adenocarcinoma in Xinjiang Uighur Autonomous Region]

OBJECTIVE

To clarify the relationship between epidermal growth factor receptor (EGFR) mutations and the clinicopathologic features of primary lung adenocarcinomas in Xinjiang.

METHODS

The mutations of EGFR gene at exons 18-21 in 59 cases (including 15 cases of Uighur and 44 cases of Han) of lung adenocarcinoma tissues, which were obtained from surgical resection, were detected by amplification refractory mutation system (ARMS) method. And the relationships among mutations, race and clinicopathologic features were analyzed.

RESULTS

The frequencies of EGFR mutations in lung adenocarcinoma were 20% for Uighur, which was lower than that in Han (54.5%), P<0.05. The deletion mutations at exon 19 were seen in 2 of 15 Uighur cases and 9 of 44 Han cases. EGFR mutations were present, including exon 21 L858R in one Uighur case and 12 Han cases, exon 18 G719X in two of 44 cases of Han, exon 21 L861Q in one of them. On histological type, the frequencies of EGFR mutation in alveolar predominant adenocarcinoma was 71% (22/31), which was higher than both that in solid predominant and mucinous carcinoma ( 6.7%, 20% respectively). According to statistic analysis, EGFR mutations were without correlation with the patient's gender, age, location, gross type, smoking status and lymph node metastasis(P>0.05). EGFR mutation was more frequent in well-differentiated cancer, mainly in acinar carcinoma, while poorly differentiated adenocarcinoma and mucous adenocarcinoma were lower.

CONCLUSION

There was a difference of EGFR mutation in primary lung adenocarcinoma between Uighur and Han in Xinjiang, perhaps reflecting ethnic genetic variation, which is worth further analyzing. EGFR mutation was commonly detected in well or middle differentiated adenocarcinoma, mainly in acinar carcinoma.

Estimation of population size based on additive hazards models for continuous-time recapture experiments

We use the semiparametric additive hazards model to formulate the effects of individual covariates on the capture rates in the continuous-time capture-recapture experiment, and then construct a Horvitz-Thompson-type estimator for the unknown population size. The resulting estimator is consistent and asymptotically normal with an easily estimated variance. Simulation studies show that the asymptotic approximations are adequate for practical use when the average capture probabilities exceed .5. Ignoring covariates would underestimate the population size and the coverage probability is poor. A wildlife example is provided.

[Coexpression of intermediate filaments in notochords and chordomas and its significance in the histogenesis and diagnosis of chordoma]

Six chordomas, ten fetal notochords and eight adult notochords were stained for keratin, vimentin, GFAP, desmin, CEA, EMA and s-100 protein. Coexpression of four kinds of intermediate filaments was common in fetal notochords and chordomas. According to the histologic and immunohistochemical characteristics, chordoma may originate from the ectopic remnants of undegenerated notochord during the embryonic stage. The chordoma consists of two cell types; nonvacuolated and physaliphorous cells, and exhibits the potentiality of multidirectional differentiation. The coexpression of different types of intermediate filaments could explain the morphological transformation of chordoma.