ABSTRACT
The creation of new families of intermetallic or Zintl-phase compounds with high-spin orbit elements has attracted a considerable amount of interest due to the presence of unique electronic, magnetic, and topological phenomena in these materials. Here, we establish the synthesis and structural and electronic characterization of KMg4Bi3 single crystals having a new structure type. KMg4Bi3 crystallizes in space group Cmcm having unit cell parameters a = 4.7654(11) Å, b = 15.694(4) Å, and c = 13.4200(30) Å and features an edge-sharing MgBi4 tetrahedral framework that forms cage-like one-dimensional channels around K+ ions. Diffuse reflectance absorption measurements indicate that this material has a narrow band gap of 0.27 eV, which is in close agreement with the electronic structure calculations that predict it to be a trivial insulator. Electronic transport measurements from 80 to 380 K indicate this material behaves like a narrow band gap semiconductor doped to â¼1018 holes/cm-3, with thermopowers of â¼100 µV/K and appreciable magnetoresistance. Electronic structure calculations indicate this material is close to a topological phase transition and becomes a topological insulator when the lattice is uniformly expanded by 3.5%. Overall, this unique structure type expands the landscape of potential quantum materials.
ABSTRACT
Background: Hypothyroidism affects 3% of pregnant women, and to date, no studies have addressed the impact levothyroxine-treated hypothyroidism on delivery outcome. Methods: This retrospective cohort study was conducted among 750 women with a singleton pregnancy who gave birth between 2015 and 2019. Delivery modes were compared between 250 hypothyroid women exposed to levothyroxine and 500 euthyroid control women. The aim of this study was to determine the impact of levothyroxine exposure on delivery outcome. Results: Multiple logistic regression showed no significant association between exposure to levothyroxine and the overall rate of caesarean delivery (aOR 1.1; 95% CI 0.8 to 1.6). Mean TSH concentrations were significantly higher throughout the pregnancy in hypothyroid women despite levothyroxine treatment. Maternal and neonatal outcomes in both groups were not different. Conclusion: Hypothyroidism treated with levothyroxine during pregnancy according to local guidelines is not a significant risk factor for caesarean delivery.
ABSTRACT
OBJECTIVE: Serous ovarian cancer is the most common subtype of epithelial ovarian carcinoma-the most prevalent type of ovarian cancer. High-grade serous ovarian carcinoma (HGSOC) is thought to arise from the distal fallopian tube, with a precursor lesion known as serous tubal intraepithelial carcinoma (STIC). STICs are found in the final pathology of a salpingectomy specimen in 10%-20% of women with a BRCA gene mutation and 1%-7% of women without a mutation. However, there is currently no official guideline and a paucity of data on the management of STICs. DATA SOURCES: We performed a systematic review following PRISMA guidelines. Five databases were searched for relevant studies on STICs. STUDY SELECTION: Two independent reviewers performed the abstract and full-text screening and data extraction, with conflicts resolved through discussion with the third reviewer. The risk of bias of each study was assessed using the Newcastle-Ottawa scale. DATA EXTRACTION AND SYNTHESIS: Fourteen articles were included. Ninety-nine patients who were diagnosed with STIC and subsequently followed for a mean period of 55.5 months were included in this analysis. Eighty-three patients (83.9%) were BRCA mutation carriers. After the diagnosis of isolated STIC, 7 patients (7.3%) received chemotherapy and 25 (26%) underwent surgical staging. Three of the 25 patients were diagnosed with HGSOC based on the staging surgery. Nine patients were later diagnosed with HGSOC during follow-up, with an average duration of follow-up of 58.5 months between the diagnosis of STIC and the diagnosis of HGSOC. CONCLUSION: Based on our review of the literature, there is a 10.7% risk of having concurrent HGSOC at the time of STIC diagnosis, and the risk of developing a subsequent HGSOC is 14.5%. BRCA mutation status should be determined in cases of isolated STIC, as 83.9% of patients included in this study were found to carry BRCA mutations. We believe it is necessary to further investigate the role of surgical staging following the diagnosis of STIC.
