Realization of continuous electron doping in bulk iron selenides and identification of a new superconducting zone.

It is known that iron selenide superconductors exhibit unique characteristics distinct from iron pnictides, especially in the electron-doped region. However, a comprehensive study of continuous carrier doping and the corresponding crystal structures of FeSe is still lacking, mainly due to the difficulties in controlling the carrier density in bulk materials. Here we report the successful synthesis of a new family of bulk Lix(C3N2H10)0.37FeSe, which features a continuous superconducting dome harboring Lifshitz transition within the wide range of 0.06 ⩽ x ⩽ 0.68 . We demonstrate that with electron doping, the anion height of FeSe layers deviates linearly away from the optimized values of pnictides and pressurized FeSe. This feature leads to a new superconducting zone with unique doping dependence of the electronic structures and strong orbital-selective electronic correlation. Optimal superconductivity is achieved when the F e 3 d t 2 g orbitals have almost the same intermediate electronic correlation strength, with moderate mass enhancement between 3 ~ 4 in the two separate superconducting zones. Our results shed new light on achieving unified mechanism of superconductivity in iron-based superconductors.

Quasi-two-dimensional superconductivity from dimerization of atomically ordered AuTe2Se4/3 cubes.

The emergent phenomena such as superconductivity and topological phase transitions can be observed in strict two-dimensional (2D) crystalline matters. Artificial interfaces and one atomic thickness layers are typical 2D materials of this kind. Although having 2D characters, most bulky layered compounds, however, do not possess these striking properties. Here, we report quasi-2D superconductivity in bulky AuTe2Se4/3, where the reduction in dimensionality is achieved through inducing the elongated covalent Te-Te bonds. The atomic-resolution images reveal that the Au, Te, and Se are atomically ordered in a cube, among which are Te-Te bonds of 3.18 and 3.28 Å. The superconductivity at 2.85 K is discovered, which is unraveled to be the quasi-2D nature owing to the Berezinsky-Kosterlitz-Thouless topological transition. The nesting of nearly parallel Fermi sheets could give rise to strong electron-phonon coupling. It is proposed that further depleting the thickness could result in more topologically-related phenomena.Emergent phenomena often appear in crystals in the two-dimensional limit but are rare in bulky compounds. Here, Guo et al. report a quasi-two-dimensional superconductivity in a bulk material AuTe2Se4/3 at 2.85 K, potentially owing to a topological transition.

[Expression of long non-coding RNA SNHG8 in Epstein-Barr virus-related gastric cancer and clinical outcome].

Objective: To investigate the expression of long non-coding RNA (lncRNA) SNHG8 in EB virus related gastric cancer and their correlation prognosis. Methods: The expression of SNHG8 in 93 gastric cancers and 93 cancer-free controls, matched by age and sex, were determined by real-time PCR. EB virus expression was detected by EBER in situ hybridization. Results: Forty-one gastric cancers were EB virus associated. For all gastric cancers, SNHG8 expression was 14 times higher (P=0.001) than that in non-cancer controls; in the EB virus related gastric cancers, SNHG8 expression was increased 25 times (P<0.05) over EB virus negative gastric cancers. SNHG8 expression level was also significantly associated with TNM staging (P<0.05). Conclusions: SNHG8 may act as a proto-oncogene, participating in gastric carcinogenesis.EB virus infection of gastric mucosa may promote SNHG8 expression.

Growth responses of broiler chickens to different periods of artificial light.

This study aimed to establish response curves between broiler chicken growth parameters and artificial light periods, as opposed to optimizing a lighting regimen for broiler production. Medium-growing broiler chickens were illuminated for periods of 12, 14, 16, 18, 20, 22, or 24 h each day. The BW of the broilers were significantly influenced by light periods ( < 0.05). Moreover, BW responded to light periods in a linear fashion, suggesting that long light periods result in greater BW. In addition, a linear relationship was found between feed intake and light periods. However, the relationship between shank length and light period was quadratic. When the light period was too short (12 h) or too long (24 h), the light stimulus did not enhance shank growth in the broiler chickens ( < 0.05). In addition, a quadratic relationship between the quantity of abdominal adipose tissue and light period suggested that the quantity of abdominal adipose decreases when the period of the light stimulus was too short or too long ( < 0.05). Moreover, a broken-stick analysis suggested that the triiodothyronine (T3) concentration in the blood was minimally affected beyond 18 h ( = 0.267), although a quadratic relationship was found between the period (from 18 to 24 h) and T3 concentrations in the blood. The response curves established in the present study will be valuable for designing future lighting regimes for medium-growing broiler strains.

Medial sural artery perforator flap aided by preoperative computed tomography angiography mapping for tongue reconstruction.

The purpose of this paper is to present an innovative method for tongue reconstruction after cancer ablation using the medial sural artery perforator flap with the aid of preoperative computed tomography angiography (CTA) mapping. We describe the case of one patient treated with this technique and illustrate the anatomy of perforator vessels and the surgical techniques used in flap harvest. CTA was applied preoperatively to assess the number and location of medial sural artery perforators. The result obtained was both aesthetically and functionally satisfactory. The flap presented has the advantage of less donor site morbidity, and being thin, it is a suitable option for tongue reconstruction including that of a hemiglossectomy defect. CTA is an effective means of improving the safety of flap harvest.

Observation of superconductivity at 30~46 K in A(x)Fe2Se2(A = Li, Na, Ba, Sr, Ca, Yb, and Eu).

New iron selenide superconductors by intercalating smaller-sized alkali metals (Li, Na) and alkaline earths using high-temperature routes have been pursued ever since the discovery of superconductivity at about 30 K in KFe2Se2, but all have failed so far. Here we demonstrate that a series of superconductors with enhanced T(c) = 30∼46 K can be obtained by intercalating metals, Li, Na, Ba, Sr, Ca, Yb, and Eu in between FeSe layers by the ammonothermal method at room temperature. Analysis on their powder X-ray diffraction patterns reveals that all the main phases can be indexed based on body-centered tetragonal lattices with a∼3.755-3.831 Å while c∼15.99-20.54 Å. Resistivities show the corresponding sharp transitions at 45 K and 39 K for NaFe2Se2 and Ba0.8Fe2Se2, respectively, confirming their bulk superconductivity. These findings provide a new starting point for studying the properties of these superconductors and an effective synthetic route for the exploration of new superconductors as well.

Structure determination and relative properties of novel chiral orthoborate KMgBO3.

A novel chiral orthoborate, KMgBO(3), has been successfully synthesized via a standard solid-state reaction, and the crystal structure has been determined from powder X-ray diffraction data. It crystallizes in the cubic chiral space group P2(1)3. Isolated [BO(3)](3-) anionic groups, which are the fundamental building units, are distributed around the 111 crystallographic direction in an axial C(3) symmetry, and the configuration of O(3) planes is helical, similar to the aplanar ClO(3) groups in NaClO(3), which indicates an optical activity in it and is validated by the circular dichroism spectrum. The chiral feature of the borate is unique, and because of the noncentrosymmetric structure, the compound exhibits nonlinear optical properties, which are validated by second harmonic generation powder measurement. It has a wide transparency, including the vacuum ultraviolet region. The relations between the structures of KMgBO(3) and NaClO(3) and structural conversion form KMgBO(3) to NaMgBO(3) are also discussed. The ionic radii, interatomic distance, and the rigid tilting of BO(3) groups are considered to be the main factors in the crystallization of different structures.

Multiple regulatory sites in the Bacillus subtilis citB promoter region.

The aconitase (citB) gene of Bacillus subtilis is repressed during growth in a medium that contains a rapidly metabolizable carbon source and a source of 2-ketoglutarate. It is derepressed when either of these nutrient sources becomes limiting. Repression by rapidly metabolizable carbon sources was shown previously to depend at least in part on a DNA sequence located 67 to 84 base pairs upstream of the start point of citB transcription. In the present work, this region and surrounding DNA were mutagenized to identify more precisely the target for carbon catabolite repression. Mutations in a symmetric sequence located between positions -73 and -59 led to constitutive transcription from the citB promoter in media that normally provoke catabolite repression. By gel mobility shift assays, it was shown that at least one protein in extracts of B. subtilis binds to the symmetric sequence and that DNA of constitutive mutants binds to this protein much less effectively. A second sequence located near position -45 was also implicated in this regulation. A second form of regulation of citB was also investigated. This gene is known to be derepressed when cells are induced to sporulate by exhaustion of a nutrient broth medium or limitation of guanine nucleotide synthesis. The mutations that led to constitutivity with respect to the carbon source had no effect on citB expression in nutrient broth medium, indicating that control by catabolite repression and control by components of nutrient broth (presumably amino acids) act by different mechanisms.