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Titanium dioxide is one of the most promising materials for many applications such as photovoltaics and photocatalysis. Non-metal doping of TiO2 is widely used to improve the photoconversion efficiency by shifting the absorption edge from the UV to visible-light region. Here, we employ hybrid density-functional calculations to investigate the energetics and optical properties of carbon (C) impurities in rutile TiO2. The predominant configurations of the C impurities are identified through the calculated formation energies under O-poor and O-rich growth conditions. Under the O-poor condition, we find that C occupying the oxygen site (CO) is energetically favorable for Fermi-level values near the conduction band minimum (n-type TiO2), and acts as a double acceptor. Under the O-rich condition, the Ci–VTi complex is energetically favorable, and is exclusively stable in the neutral charge state. We also find that interstitial hydrogen (Hi) can bind to CO, forming a CO–Hi complex. Our results suggest that CO and CO–Hi are a cause of visible-light absorption under oxygen deficient growth conditions.

The substitutional C on O site and its complex with H are a cause of visible-light absorption in rutile TiO2.  相似文献   
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ABSTRACT

Objectives: The primary objective was to determine the prevalence of calreticulin (CALR) mutation in patients with non-JAK2V617F mutated essential thrombocythemia (ET). The secondary objectives were to evaluate the accuracy of CALR mutation analysis by high-resolution melting (HRM) analysis and real-time polymerase chain reaction (PCR) compared with DNA sequencing and to compare clinical characteristics of CALR mutated and JAK2V617F mutated ET.

Methods: This was a prospective cohort study involving ET patients registered at Chiang Mai University in the period September 2015–September 2017 who were aged more than 2 years, and did not harbor JAK2V617F mutation. The presence of CALR mutation was established by DNA sequencing, HRM, and real-time PCR for type 1 and type 2 mutation. Clinical data were compared with that from ET patients with mutated JAK2V617F.

Results: Twenty-eight patients were enrolled onto the study. CALR mutations were found in 10 patients (35.7%). Three patients had type 1 mutation, 5 patients had type 2 mutation, 1 patient had type 18 mutation, and 1 patients had novel mutations (c.1093 C–G, c.1098_1131 del, c.1135 G–A). HRM could differentiate between the types of mutation in complete agreement with DNA sequencing. Patients with a CALR mutation showed a significantly greater male predominance and had a higher platelet count when compared with 42 JAK2V617F patients.

Discussion and Conclusions: The prevalence of CALR mutation in JAK2V617F-negative ET in this study is 35.7%. HRM is an effective method of detecting CALR mutation and is a more advantageous method of screening for CALR mutation.  相似文献   
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PURPOSE: To describe the ophthalmic findings and mutation analyses of the PAX6 gene in Thai aniridia patients. METHODS: Ten patients from six unrelated families underwent a comprehensive ophthalmic examination. Mutations in the PAX6 gene were screened by single-strand conformational polymorphism (SSCP) and direct DNA sequencing of the SSCP variants. RESULTS: Seven patients developed cataracts and six developed glaucoma. Mutation analysis demonstrated four different truncating mutations, two of which were de novo. These included one novel insertion/deletion mutation (c.474del12insGA in exon 5) and three nonsense mutations. R203X and R240X are common recurrent mutations, while Q277X in exon 10 is novel. All mutations resulted in loss of function of the PAX6 protein. CONCLUSION: Our data confirm inter- and intrafamilial variable phenotypic manifestations of which the underlying mechanisms may be haploinsufficiency or dominant-negative mutation.  相似文献   
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This report describes a rare case of parosteal ossifying lipoma of the fibula. Very few reports have described the magnetic resonance (MR) imaging features with gadolinium enhancement of this neoplasm. In this case, low-signal-intensity strands within the lipomatous mass on T1-weighted image with varying degrees of enhancement were detected. Thus, parosteal ossifying lipoma should be included within the group of gadolinium-enhanced benign lipomatous tumours that may mimic liposarcoma on MR imaging. However, the characteristic radiographic appearance, together with computed tomography or MR imaging features, should aid in the correct diagnosis of this condition.  相似文献   
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Purpose  Since 1997, our institute has used neoadjuvant chemotherapy for intraocular retinoblastoma. However, some of the patients showed signs of recurrence months to years later. We therefore attempted to determine the prognostic factors of treatment outcomes and survival in our patients. Methods  We reviewed 90 patients treated from 1997 to 2006. The following information was recorded: demographic and ophthalmological data, clinical classification, histopathological data, and treatment methods and outcomes. Results  Enucleation was avoided in two of 57 eyes in the unilateral group. Sixteen of 54 eyes in the bilateral group were salvaged by systemic chemotherapy with local treatment. There was no difference in histopathological findings between the two groups. Nine of 57 patients in the unilateral group demonstrated poor outcomes, compared with four of 27 in the bilateral group. Significant poor prognostic factors for survival were optic nerve head invasion, orbital involvement, abnormal results on bone marrow aspiration, lumbar puncture, bone scan, and group E or F classification. Conclusions  The 15% mortality rate in our patients is slightly higher than that reported in developed countries. Delayed diagnosis and treatment is the main cause of avoidable deaths. Improving education of both clinicians and parents would increase survival rates in this potentially fatal disease.  相似文献   
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