Surface and Core Electronic Structure of Oxidized Silicon Nanocrystals

Ab initio restricted Hartree-Fock method within the framework of large unit cell formalism is used to simulate silicon nanocrystals between 216 and 1000 atoms (1.6–2.65 nm in diameter) that include Bravais and primitive cell multiples. The investigated properties include core and oxidized surface properties. Results revealed that electronic properties converge to some limit as the size of the nanocrystal increases. Increasing the size of the core of a nanocrystal resulted in an increase of the energy gap, valence band width, and cohesive energy. The lattice constant of the core and oxidized surface parts shows a decreasing trend as the nanocrystal increases in a size that converges to 5.28 Ǻ in a good agreement with the experiment. Surface and core convergence to the same lattice constant reflects good adherence of oxide layer at the surface. The core density of states shows highly degenerate states that split at the oxygenated (001)-(1×1) surface due to symmetry breaking. The nanocrystal surface shows smaller gap and higher valence and conduction bands when compared to the core part, due to oxygen surface atoms and reduced structural symmetry. The smaller surface energy gap shows that energy gap of the nanocrystal is controlled by the surface part. Unlike the core part, the surface part shows a descending energy gap that proves its obedience to quantum confinement effects. Nanocrystal geometry proved to have some influence on all electronic properties including the energy gap

Klatskin Tumor in the Light of ICD-O-3: A Population-Based Clinical Outcome Study Involving 1,144 Patients from the Surveillance, Epidemiology, and End Result (SEER) Database (2001-2012)

Introduction: Klatskin tumors (KTs) occur at the confluence of the right and left extrahepatic ducts and are classified based on their anatomical and histological codes in the International Classification of Diseases for Oncology (ICD-O). The second edition of the ICD-O (ICD-O-2) allocated a distinctive histological code to KT, which also included intrahepatic cholangiocarcinoma (CC). This unclear coding may result in ambiguous reporting of the demographic and clinical features of KT. The current study aimed to investigate the demographic, clinical, and pathological factors affecting the prognosis and survival of KT in the light of the updated third edition of ICD-O, Ninth Revision (ICD-O-3). Methods: Data of 1,144 patients with KT from the Surveillance, Epidemiology, and End Result (SEER) database (2001-2012) were extracted. Patients with KT were analyzed for age, sex, race, stage, treatment, and long-term survival. The data were analyzed using chi-square tests, t-tests, and univariate and multivariate analyses. The Kaplan-Meier analysis was used to compare long-term survival between KT and subgroups of all biliary CCs. Results: Of all biliary CCs, KT comprised 9.35%, with a mean age of diagnosis of 73±13 years, and was more common in men (54.8%) and Caucasian patients (69.5%). Histologically, moderately differentiated tumors were the most common (38.9%) followed by poorly differentiated (35.7%), well-differentiated (23.3%), and undifferentiated tumors (2.2%) (p4 cm (29.7%) and <2 cm (28.8%) (p<0.001). ICD-O-3 defined most KTs in extrahepatic location (53.5%), while the remainder were in other biliary locations (46.5%) (p<0.001). Most KT patients received no treatment (73%), and for those who were treated, the most frequent modality was radiation (52.7%), followed by surgery (28.1%), and both surgery and radiation (19.2%) (p<0.001). Mean survival time for KT patients treated with surgery was inferior to all CCs of the biliary tree (1.72±2.61 vs. 1.87±2.18 years) (p=0.047). Multivariate analysis identified regional metastasis (OR=2.8; 95% CI=2.6-3.0), distant metastasis (OR=2.1; 95% CI=1.9-2.4), lymph node positivity (OR=1.6; 95% CI=1.4-1.8), Caucasian race (OR=2.0; 95% CI=1.8-2.2), and male sex (OR=1.2; 95% CI=1.1-1.3) were independently associated with increased mortality for KT (p<0.001). Conclusion: The ICD-O-3 has permitted a greater understanding of KT. KT is a rare and lethal biliary malignancy that presents most often in Caucasian men in their seventh decade of life with moderately differentiated histology. Surgical resection does not provide any survival advantage compared to similarly treated biliary CCs. In addition, the combination of surgery and radiation appeared to provide no added survival benefits compared to other treatment modalities for KT

Colorectal Cancer Screening Challenges in the Recent Afghan Refugee Population: A Comprehensive Review Article

Colorectal cancer (CRC) is more prevalent in south-central Asian countries, particularly the Afghan population. Screening for CRC in the Afghan population has always been challenging, primarily due to the tribal and social cultures, lack of facilities, and lack of education. The United States (US) will soon face a significantly massive influx of Afghan refugees. It becomes imperative to initiate and implement effective measures regarding CRC screening in these refugee populations. The current review article aims to identify the most likely challenges faced for CRC screening in this Afghan refugee population in the US and address the possible measures to overcome these challenges

Prognostic Value of Lymph Node Ratio in Cutaneous Melanoma: A Systematic Review

The prognosis of cutaneous melanoma (CM) is based on the histological characteristics of the primary tumor, such as Breslow depth, ulceration, and mitotic rate. The lymph node ratio (LNR) is the ratio of the involved lymph nodes (LNs) divided by the total number of LNs removed during regional LN dissection. LNR is a prognostic factor for many solid tumors; however, controversies exist regarding CM. This study sought to analyze the role of LNR as a prognostic factor in CM. An extensive literature search was conducted using PubMed, Google Scholar, Medline, and the Cochrane Central Registry of Controlled Trials from January 1966 to July 2015. The keywords included in the search were CM and inclusion of the ratio of positive to the total number of LNs as a prognostic factor. The outcomes analyzed included the number of patients with positive LNs, type of survival analysis, and results from the multivariate analysis. A total of 11 studies involving 12,011 patients with positive LNs were evaluated. No previous randomized controlled trials, meta-analyses, or systematic reviews were identified in the Cochrane database on the prognostic value of LNR in CM. The primary electronic database search resulted in 333 full-text articles. The LN location examined was the cervical, axillary, and inguinal regions in all studies except for one that examined only the inguinal region. All studies except three studied the prognostic value of the LNR as a categorical variable rather than a continuous variable. LNR was categorized as A (≤0.1), B (0.11-0.25), and C (>0.25). All studies identified LNR as an independent predictor of overall survival (OS), disease-free survival (DFS), or disease-specific survival (DSS). The hazard ratio (HR) and confidence interval (CI) associated with either DFS or OS were available only in a few studies. Moreover, pooled HR for OS was 2.08 (95% CI: 1.48 2.92), for DFS was 1.364 (95% CI: 0.92-2.02), and for DSS was 1.643 (95% CI: 0.89-3.0). The LNR provides superior prognostic stratification among patients with CM. Additional adequately powered prospective studies are needed to further define the role of LNR and be included in the staging system of CM and direct adjuvant therapy

Incidence, Survival Analysis and Future Perspective of Primary Peritoneal Mesothelioma (PPM): A Population-Based Study from SEER Database

Background: Primary peritoneal mesothelioma (PPM) is a rare and aggressive tumor arising from the visceral and parietal peritoneum. The diagnosis and treatment of PPM are often delayed because of non-specific clinical presentation, and the prognosis is worse. The current study investigated the demographic, clinical, and pathological factors affecting patient prognosis and survival in PPM. Methods: Demographic and clinical data of 1998 patients with PPM were extracted from the Surveillance Epidemiology and End Results (SEER) database (1975–2016). The chi-square test, paired t-test, and multivariate analysis were used to analyze the data. Results: The majority of PPM patients were male (56.2%, p p 4 cm in size (8%), respectively, were most common, p p 4 cm (OR = 3.9, CI = 3.2–4.5), Caucasian race (OR = 2.9, CI = 2.6–4.4), and distant SEER stage (OR = 2.5, CI = 1.1–3.2) were all linked with increased mortality (p < 0.001). Conclusion: An extremely rare and aggressive peritoneal tumor, PPM may be difficult to identify at the time of diagnosis. Radiation therapy likely to have a limited function in the treatment of this condition, with surgery and chemotherapy being the primary choices. All PPM patients should be enrolled in a nationwide registry to improve our understanding of the pathogenesis and identify factors affecting survival

Miscarriage And Ectopic Pregnancy

Vaginal bleeding during the first trimester of the pregnancy is one of the most common clinical scenarios encountered in Obstetrics and Gynecology, occurring in approximately one fourth of all pregnancies. The differential diagnosis of first trimester bleeding classically includes not only ectopic pregnancy (EP), but also miscarriage, and gestational trophoblastic disease. Miscarriage or spontaneous abortion is one of the most common complications of the pregnancy. Surgery is the definitive treatment of an ectopic pregnancy. Medical management of ectopic pregnancy, primarily with MTX (MTX), is a non‐invasive alternative to surgery. Ultrasound‐guided intra‐ectopic injection of MTX or other substances, including prostaglandins, potassium chloride, and hyperosmolar glucose have been described, usually with concurrent aspiration of the gestational sac, for the treatment of an ectopic pregnancy. Although the systemic administration of MTX is easier, local injection has been described in an effort to minimize the risk of systemic side effects