Pressure-induced linear enhancement of the superconducting transition in Nd0.8Sr0.2NiO2thin films.

We report the pressure (P) effect on the superconducting transition temperatureTcand the upper critical fieldµ0Hc2of infinite-layer Nd0.8Sr0.2NiO2thin films by measuring the electrical transport properties under various hydrostatic pressures to 4.6 GPa. At ambient pressure, it shows the clear superconducting transition withTc∼ 10 K. Based on the evolution of resistanceR(T), we found that theTcis monotonically enhanced to ∼14 K upon increasing pressure to 2.9 GPa. The constructed temperature-pressure phase diagram indicates that the calculated slope dTc/dPis about 1.14 K GPa-1and the superconductingTcshows no signatures of saturation with pressure. It thus gives the possibility to further enhanceTcby employing higher pressures or heterostructure engineering. In addition, the normalized slope of upper critical fieldµ0Hc2(0) implies that the electron correlations are gradually decreasing with pressure, which exhibits an opposite evolution with superconductingTc. Our work further confirms the positive pressure effects in nickelate superconductors and gives more insight to further enhance its superconducting transition temperature.

[Bibliometric and bioinformatics analysis of genetic literature on susceptibility to noise induced hearing loss].

Objective: To summarize and analyse of literature on the susceptibility genes of noise induced hearing loss (NIHL) , and the key genes were screened and obtained by bioinformatics method, so as to provide reference for the prevention research of NIHL. Methods: In September 2021, Based on CNKI, NCBI Pubmed database and Web of Science database, this paper conducted bibliometric analysis and bioinformatics analysis on the genetic literature related to the susceptibility to noise-induced hearing loss from 1999 to 2020. Endnote X9 software and the WPS office software were used for bibliometric analysis, and online software STRING and Cytoscape software were used for bioinformatics analysis. Results: A total of 131 literatures were included in the study, involving 40 genes in total. Bibliometric analysis shows that 131 papers which included 36 Chinese articles and 95 English articles were published in 63 biomedical journals; the highest number of published articles was 19 in 2020. Bioinformatics analysis suggests that GAPDH、SOD2、SOD1、CAT、CASP3、IL6 and other genes play a key role in the interaction network. The involved pathways mainly include MAP2K and MAPK activations, PTEN regulation, P53-depardent G1 DNA damage response, signaoling by BRAF and RAF fusions and soon. Conclusion: The study of noise induced hearing loss involves multi gene biological information, and bioinformatics analysis is helpful to predict the occurrence and development of noise induced hearing loss.

[Treatment and prognosis of multiple primary malignant neoplasms complicated with renal cell carcinoma].

OBJECTIVE: To investigate the treatment and prognosis of multiple primary malignant neoplasms (MPMN) complicated with renal cell carcinoma (RCC), and to make risk stratification. METHODS: A retrospective study of 27 cases of MPMN with RCC in two centers, including the different tumors of MPMN, specific treatment methods, and the interval between primary cancers. At the same time, the survival conditions, including recurrence, metastasis and survival, were followed up for statistical analysis. The interval between the two kinds of primary cancer within 6 months was simultaneous MPMNs, and more than 6 months was metachronous MPMNs. For simple risk stratification of cases, as long as one of the MPMNs had a stage Ⅲ or higher malignancy, which was defined as high risk. RESULTS: Among the 27 patients, 20 were male and 7 were female, with age at the time of diagnosis was 42-82 years, with an average age of (61.3±11.7) years. The age at the diagnosis of renal cancer was 43-87 years, with an average age of (66.0±11.3) years. There were 21 cases with duplex primary malignant neoplasms, 4 cases with triple primary malignant neoplasms, and 2 cases with quadruple primary malignant neoplasms. The interval between first cancer and second cancer was 0-360 months, with a median of 18 months. There were 17 cases of metachronous multiple primary malignant neoplasms and 10 cases of simultaneous multiple primary malignant neoplasms. The most common system of MPMN with comorbid RCC involved urologic system, digestive system and respiratory system. The most common locations of MPMN with comorbid RCC were bladder cancer, lung cancer and colon cancer. Follow-up time calcu- lated from the last cancer was 2-156 months, with a median of 32 months. And 14 cases survived and 13 cases died, with 11 cases being tumor related. Tumor stage was the risk factor of prognosis. Any kind of tumor stage in stage Ⅲ or above had a relatively poor prognosis. CONCLUSION: MPMN complicated with RCC is relatively rare. Standard treatment should be used for each cancer type during the treatment process. The prognosis mainly depends on the highest stage of each tumor. Simple risk stratification shows that the prognosis of the high-risk group is worse. This simple stratification method may be helpful to predict the prognosis.

Improved Limit on Tensor Currents in the Weak Interaction from

The electroweak interaction in the standard model is described by a pure vector-axial-vector structure, though any Lorentz-invariant component could contribute. In this Letter, we present the most precise measurement of tensor currents in the low-energy regime by examining the ß-ν[over ¯] correlation of trapped ^{8}Li ions with the Beta-decay Paul Trap. We find a_{ßν}=-0.3325±0.0013_{stat}±0.0019_{syst} at 1σ for the case of coupling to right-handed neutrinos (C_{T}=-C_{T}^{'}), which is consistent with the standard model prediction.

Pressured-induced superconducting phase with large upper critical field and concomitant enhancement of antiferromagnetic transition in EuTe2.

We report an unusual pressure-induced superconducting state that coexists with an antiferromagnetic ordering of Eu2+ moments and shows a large upper critical field comparable to the Pauli paramagnetic limit in EuTe2. In concomitant with the emergence of superconductivity with Tc ≈ 3-5 K above Pc ≈ 6 GPa, the antiferromagnetic transition temperature TN(P) experiences a quicker rise with the slope increased dramatically from dTN/dP = 0.85(14) K/GPa for P ≤ Pc to 3.7(2) K/GPa for P ≥ Pc. Moreover, the superconducting state can survive in the spin-flop state with a net ferromagnetic component of the Eu2+ sublattice under moderate magnetic fields µ0H ≥ 2 T. Our findings establish the pressurized EuTe2 as a rare magnetic superconductor possessing an intimated interplay between magnetism and superconductivity.

Pressure-Induced Superconductivity up to 9 K in the Quasi-One-Dimensional KMn_{6}Bi_{5}.

The Mn-based superconductor is rare owing to the strong magnetic pair-breaking effect. Here we report on the discovery of pressure-induced superconductivity in KMn_{6}Bi_{5}, which becomes the first ternary Mn-based superconductor. At ambient pressure, the quasi-one-dimensional KMn_{6}Bi_{5} is an antiferromagnetic metal with T_{N}≈75 K. By measuring resistance and ac magnetic susceptibility under hydrostatic pressures up to 14.2 GPa in a cubic anvil cell apparatus, we find that its antiferromagnetic transition can be suppressed completely at a critical pressure of P_{c}≈13 GPa, around which bulk superconductivity emerges and displays a superconducting dome with the maximal T_{c}^{onset}=9.3 K achieved at about 14 GPa. The close proximity of superconductivity to a magnetic instability in the temperature-pressure phase diagram of KMn_{6}Bi_{5} and an unusually large µ_{0}H_{c2}(0) exceeding the Pauli paramagnetic limit suggests an unconventional magnetism-mediated paring mechanism. In contrast to the binary MnP, the flexibility of the crystal structure and chemical compositions in the ternary AMn_{6}Bi_{5} (A=alkali metal) can open a new avenue for finding more Mn-based superconductors.

Using Rasch Analysis to Validate the Michigan Hand Outcomes Questionnaire from the Wrist and Radius Injury Surgical Trial.

BACKGROUND: The Michigan Hand Outcomes Questionnaire is a patient-reported outcome measure that has been validated in many upper extremity disorders using classic test theory. Rasch measurement analysis is a rigorous method of questionnaire validation that offers several advantages over classic test theory and was used to assess the psychometric properties of the Michigan Hand Outcomes Questionnaire. This study used Rasch analysis to evaluate the questionnaire for distal radius fractures in older adults. The incidence and costs of distal radius fractures are rising, and reliable assessment tools are needed to measure outcomes in this growing concern. METHODS: Rasch analysis was performed using 6-month assessment data from the Wrist and Radius Injury Surgical Trial. Each domain in the Michigan Hand Outcomes Questionnaire was independently analyzed for threshold ordering, person-item targeting, item fit, differential-item functioning, response dependency, unidimensionality, and internal consistency. RESULTS: After collapsing disordered thresholds and removing any misfitting items from the model, five domains (Function, Activities of Daily Living, Work, Pain, and Satisfaction) demonstrated excellent fit to the Rasch model. The Aesthetics domain demonstrated high reliability and internal consistency but had poor fit to the Rasch model. CONCLUSIONS: Rasch analysis further supports the reliability and validity of using the Michigan Hand Outcomes Questionnaire to assess hand outcomes in older adults following treatment for distal radius fractures. Results from this study suggest that questionnaire scores should be interpreted in a condition-specific manner, with more emphasis placed on interpreting individual domain scores, rather than the summary Michigan Hand Outcomes Questionnaire score.

[Targeted binding of rs1053005 locus of STAT3 with miR-452-3p and the association between STAT3 gene polymorphism and noise-induced hearing loss].

Objective: To investigate the relationship between rs1053005 of signal conversion and transcription activator 3 (STAT3) and miR-452-3p, and the association between STAT3 gene polymorphism and noise-induced hearing loss (NIHL) . Methods: In December 2017, 1220 workers were selected from an automobile manufacturing factory, an energy company and a chemical fiber factory in Jiangsu Province who had occupational noise exposure and working age of more than 3 years. The workers with the mean hearing threshold of ≥26 dB (A) of the two ear high frequency (3000, 4000 and 6000 Hz) were defined as case group (n=609) , and the rest were control group (n=611) . Five single nucleotide polymorphism (SNP) sites of STAT3 (rs4796793, rs1053023, rs1053005, rs1053004 and rs3744483) were selected to explore the association between STAT3 gene polymorphism and NIHL by analyzing the points. The double luciferase reporter gene verified whether miR-452-3p was targeted to bind STAT3, and overexpressed miR-452-3p in HEI-OC1 cells to explore the mechanism of STAT3 expression regulation. Results: There was no significant difference in gender, age, smoking and drinking between the two groups (P>0.05) . Compared with the control group[ (15.58±4.76) dB], the mean hearing threshold of the case group [ (37.50±12.39) dB] was higher, and the difference were statistically significant (P<0.05) . Compared with the control group, the C alleles of rs1053023 and rs1053005 were higher in the case group (OR=1.367, 1.370, P<0.05) . The risk of NIHL in men with TC/CC genotype were 1.545 and 1.531 times higher than that in men with TT genotype (P<0.05) . Compared with the control group, the mRNA expression of STAT3 in the case group was significantly increased (P<0.05) . The STAT3 mRNA expression of miR-452-3p group cells was significantly decreased (P<0.05) . Conclusion: The rs1053023 and rs1053005 polymorphism of STAT3 are related to NIHL. The C alleles of rs1053023 and rs1053005 may be biomarkers of workers exposed to noise.

[Targeted therapy of pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome (PAPA): a case report and literature review].

Objective: To analyze the clinical course and targeted therapy of pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome. Methods: The clinical history of a 6-year-old boy with PAPA syndrome, who was admitted to Hong Kong University Shenzhen Hospital in September 2017, was reviewed. His genetic diagnosis was confirmed by whole exome sequencing. The response to targeted therapy was evaluated by comparing the inflammatory markers (erythrocyte sedimentation rate (ESR) and C reactive protein (CRP) and serum cytokines (interleukin (IL)-1, IL-6 and tumor necrosis factor-α (TNF-α)) before and after biological agents treatment. For literature review, "PAPA syndrome" and"PSTPIP1 gene"were used as keywords to retrieve papers published from January 1997 to December 2019 from Pubmed, Wanfang and CNKI database. Results: The patient was a 6-year-old boy, admitted to the hospital due to recurrent joint swelling and pain for more than 4 years. Before treatment, the CRP (256 mg/L), ESR (105 mm/1 h) and cytokines including serum TNF-α (7.43 ng/L), IL-1 (<5 ng/L), IL-6 (301 ng/L) were significantly elevated. Culture of the joint effusion was negative, but the IL-6 level was above 1 000 ng/L. MRI showed osteomyelitis at the lower end of the right femur. Gene detection found a heterozygous variation of PSTPIP1 gene (c.748G>A, p.E250K). Arthralgia once alleviated after the initiation of tocilizumab and infliximab, but recurred after 1 year of treatment. Thereafter, the anti-IL-1 receptor antagonist (Anakinra) was commenced, followed by a significant improvement of the arthralgia, and a complete remission during the follow-up. Besides, the level of CRP, ESR, serum TNF-α, IL-1 and IL-6 were all decreased to normal on the last followed up in December 2019. Literature review found 29 articles and 87 patients in total. The initial symptoms included those of arthritis (n=58), pyoderma gangrenosum (n=33), and acne (n=24). Among all the cases, 13 genotypes were confirmed, and 47 variations involved amino acid p.E250. Steroid and/or biological agents were used in most patients. Conclusions: PAPA syndrome should be suspected in children with recurrent pyogenic sterile arthritis, and an early diagnosis could be achieved by genetic test. Targeted treatment with biological agent may control the symptoms effectively. Biological agents can control symptoms of this disorder effectively.

[Usefulness of the indocyanine green fluorescence imaging technique in laparoscopic partial nephrectomy].

OBJECTIVE: To detail a novel technique for marking renal tumors with intravenous indocyanine green (ICG) during laparoscopic partial nephrectomy, and to investigate the feasibility and safety of this technique with the use of near-infrared fluorescence imaging. METHODS: Between July 2019 and January 2020, 25 consecutive cases with renal masses underwent intraoperative ICG tumor marking laparoscopic partial nephrectomy, at the department of urology in Peking University Third Hospital by the same surgeon. The key benefits included quick intraoperative identification of the mass with improved visualization and real-time control of resection margins by the ICG Immunofluorescence imaging technique. Clinical data were prospectively collected in our institutional database. Perioperative, pathological, and clinical outcomes of the partial nephrectomy were assessed. Measurement data with normal distribution and count data were respectively described as M(range) and percentage. Among these cases, 16 cases were male and 9 cases female, The median body mass index was 25.4 (20.0-35.4) kg/m2. The average age was 54 (29-77) years. The maximum tumor diameter was 2.75(1.30-5.20) cm. The R.E.N.A.L score was 7.5 (5.0-10.0).The tumor locations were distributed with upper pole (11, 42%), middle (6, 23%), and lower pole (9, 35%).The clinical stages of the tumor were described as follows: T1aN0M0 (23, 88.5%), T1bN0M0(2, 7.7%), T2aN0M0 (1, 3.8%). RESULTS: All the 25 cases were performed 26 times with intraoperative ICG tumor marking laparoscopic partial nephrectomy. There were no allergy, infection and other complications with intravenous indocyanine green. The surgical procedure was successful in all the patients. No conversion and blood transfusion were needed. All the cases of the surgical margin were negative. Overall the operative time was 136 (50-247) min and warm ischemia time was 14 (7-30) min.The estimated blood loss was 50 (10-400) mL and the hospital stay was 5.5 (3.0-31.0) days. One case with perirenal hematoma, one case with urine leak, one with respiratory failure and deep venous thrombosis. All of these cases were cured by the corresponding treatment. The others had no severe complications. There was no tumor recurrence and metastasis during the follow up with 4 to 10 months. CONCLUSION: ICG marking and near-infrared fluorescence imaging technology has now emerged as a safe, feasible and useful tool that may facilitate laparoscopic partial nephrectomy.

[Analysis of self-control trial results of narrow band imaging and white light in transurethral resection of bladder tumor].

OBJECTIVE: To investigate the effect of NBI assisted white light transurethral resection of bladder tumor (TURBT) in the treatment of bladder urothelial carcinoma and to summarize the experience of narrow band imaging (NBI) operation. METHODS: Patients with bladder urothelial carcinoma were selected, and TURBT was performed after anesthesia. First of all, the bladder tumor was found and resected under white light. Then we replaced with NBI, looked for suspicious lesions and resected them, The specimens excised under white light and NBI were collected separately. The number, location and pathological results of the lesions under white light were recorded, and the residual lesions under NBI were also recorded. To evaluate the effect of NBI, the ratio of residual bladder tumor was calculated. The cases were divided into three groups according to the time sequence. The clinical data of each group were collected and the learning curve of TURBT under NBI assisted white light was observed. RESULTS: A prospective study of 45 patients with bladder tumor from April 2018 to January 2020, including 32 males and 13 females, aged from 23 to 89 years, with an average age of 65.2 years. All the operations were successfully completed, without obvious complications after operation. Nine cases were single and 36 cases were multiple. The maximum diameter of the tumors was 0.5 to 4.0 cm, with an average of 2.2 cm. The histopathology of the resected tissue under white light was urothelial carcinoma, and 19 cases (42.2%) were pathologically positive by NBI resection. The 45 cases were divided into three groups according to the time sequence, 15 cases in each group. The true positive rate of NBI was 33.3%, 46.7% and 46.7%, respectively, and the false positive rate was 60.0%, 46.7% and 26.7%, respectively in the three groups. CONCLUSION: TURBT is an effective way to treat bladder urothelial cancer, NBI is an effective supplement of white light, which can increase the detection rate of bladder cancer and reduce post-operative recurrence. The NBI light source has a certain learning curve. With the increase of cases, the false-positive rate of NBI is gradually reduced. After the NBI operator has rich experience, the recognition degree of flat tumor is gradually improved under white light, and the residual rate of NBI is reduced after the removal under white light.

[Role and implementation experience of splints in pediatric burn rehabilitation].

The maintenance of posture and anti-contracture treatment are the critical elements of comprehensive burn rehabilitation in the overall treatment period of pediatric burns. Although domestic experts in burn discipline have formulated guidelines for burn rehabilitation, the maintenance of posture and design and manufacture of splints for anti-scar contractures in children with burns are different from that for adults with burns in many ways. Starting with paying the attention to the rehabilitation problems in pediatric burns, especially considering the anatomical, psychological, and social behavior characteristics of children in developmental period, the author's team effectively applies splints to maximize the prevention of contractures in children and maintain and improve the range of their joint movements. The splints designed to prevent contractures in pediatric burns shall fit the small limb and meet their expected goals of rehabilitation. In each aspect of the production and use of splints, it is necessary to fully evaluate and consider the scar characteristics, growth and development status, activity level, and compliance of children, and adaptability and fixation methods of the splints, so as to select the appropriate splint type and formulate the wearing plan.

[Effect of silencing hepatocyte growth factor receptor c-Met expression on biological characteristics of colon cancer cells].

Objective: To investigate the effect of silencing hepatocyte growth factor receptor (c-Met) expression on the biological characteristics of HCT116 colon cancer cells. Methods: Cellular model of c-Met transient transfection was established by using small interfering RNA (siRNA), the expression of c-Met in colon cancer cells was detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and western blot. The apoptosis assay, cell invasion assay, cell migration and other experiments were conducted to observe the effects of silencing c-Met on the biological characteristics of colon cancer cells. Results: RT-qPCR results showed that the relative expression levels of c-Met mRNA in siRNA-Met group, blank control group and siRNA negative control (siRNA-NC) group were 0.32±0.26, 1.01±0.03 and 1.05±0.23, respectively, and the difference was statistically significant (P<0.05). Western blot analysis showed that the expression level of c-Met protein in the siRNA-Met group was 0.24±0.03, significantly lower than 1.23±0.06 in the blank control group and 1.18±0.11 in the siRNA-NC group (P<0.05). The cell counting kit-8 (CCK8) results showed that the 72-hour absorbance (A) values of the siRNA-Met group, blank control group and the siRNA-NC group were 1.13±0.05, 1.48±0.08 and 1.53±0.07, respectively, and the difference was statistically significant (P<0.01). Cell cycle results showed that the proportion of cells in G(2)/M phase was (14.65±1.41)% in siRNA-Met group , (5.07±0.70)% in blank control group and (5.63±0.71)% in siRNA-NC group, and the difference was statistically significant (P<0.05). The expression levels of cell cycle regulatory proteins Cdc25c and cyclin B1 in siRNA-Met group were significantly decreased. The apoptotic rate in siRNA-Met group was (5.85±0.35)%, significantly higher than (1.00±0.17)% in blank control group and (0.91±1.14)% in siRNA-NC group (P<0.05). The expression level of apoptosis-related protein Bcl-2 in the siRNA-Met group was significantly decreased while Bcl-2 associated X protein (BAX) expression level was significantly increased. The cell scratching result showed that the cell migration abilities of the siRNA-Met group, blank control group and the siRNA-NC group were (51.33±8.62)%, (100.00±3.72)% and (102.33±6.43)%, respectively, and the difference was statistically significant (P<0.05). The number of cell penetrating into the basement membrane of the siRNA-Met group, blank control group and the siRNA-NC group were 47.50±10.60, 100.00±5.33 and 102.50±10.61, respectively, and the difference was statistically significant (P<0.05). The expressions of invasion related proteins including MMP-2 and MMP-9 in siRNA-Met group were decreased significantly. Conclusions: c-Met plays an important role in maintaining the biological characteristics of colon cancer cells. Inhibition of c-Met may have important values in the treatment of colon cancer.

[Expression of long-chain non-coding RNA LINC00152 in laryngeal squamous cell carcinoma and its clinical significance].

Objective:The aim of this study is to explore the relative expression level of LINC00152 in laryngeal squamous cell carcinoma（LSCC） and its clinical significance. Method:The relative expression levels of LINC00152 in LSCC cell lines and 36 paired LSCC specimens were measured by qRT-PCR method. And the correlations between the expression level of LINC00152 and the clinical features derived from LSCC patients were analyzed and compared through the independent sample t-test. Result:The relative expression level of LINC00152 was over-expressed in LSCC cell lines and cancerous tissues than that in paired adjacent normal tissues, and the difference was statistically significant（P=0.006）. Even the associations between LINC00152 expression level and clinicopathological features（P=0.044 for clinical stage, P=0.032 for pathological differentiation degree） were significantly. Conclusion:LINC00152 is highly expressed in LSCC and it may become a new tumor marker for the diagnosis and prognosis of LSCC.

Global transcriptome analysis provides new insights in Thellungiella salsuginea stress response.

Thellungiella salsuginea is highly tolerant to abiotic stress, while its a close relative Arabidopsis thaliana is sensitive to stress. This characteristic makes T. salsuginea an excellent model for uncovering the mechanisms of abiotic stress tolerance. Abscisic acid (ABA) plays essential roles in plant abiotic and biotic stress tolerance. To test the changes in gene expression of T. salsuginea under ABA treatment, in this study, the transcriptomes of T. salsuginea roots and leaves were compared in response to exogenously application of ABA. The results showed that ABA treatment caused different expression of 2,200 and 3,305 genes in leaves and roots, respectively, compared with the untreated control. In particular, genes encoding transcription factors such as WRKY, MYB, NAC, GATA, ethylene-responsive factors (ERFs), heat stress transcription factors, basic helix-loop-helix, PLATZ and B3 domain-containing family members were enriched. In addition, 49 and 114 differentially expressed genes were identified as ABA-regulated genes, separately in leaves and roots, respectively, which were related to biotic and abiotic stresses. The expression levels of some genes were validated by qRT-PCR. Different responses of genes to ABA treatment were discovered in T. salsuginea and A. thaliana. This transcriptome analysis expands our understanding of the role of ABA in stress tolerance in T. salsuginea. Our study provides a wealth of information for improving stress tolerance in crop plants.

Effect of pressure on the self-hole-doped superconductor RbGd2Fe4As4O2.

RbGd2Fe4As4O2 is a newly discovered self-hole-doped stoichiometric superconductor, which has a hybrid structure with separated double FeAs layers and exhibits a high superconducting transition temperature T c = 35 K. Here, we report the effect of pressure (P) on its T c and normal-state transport properties by measuring the temperature dependence of resistivity ρ(T) under various pressures up to 14 GPa with a cubic anvil cell apparatus. We found that the T c is suppressed monotonically to ca. 12.5 K upon increasing pressure to 14 GPa with a slope change of T c(P) at around 4 GPa. In addition, the low-temperature normal-state ρ(T), which is proportional to T n , also evolves gradually from a non-Fermi-liquid with n = 1 at ambient pressure to a Fermi liquid with n = 2 at P ⩾ 4 GPa. Accompanying with the non-Fermi-liquid to Fermi-liquid crossover, the quadratic temperature coefficient of resistivity, which reflects the effective mass of charge carriers, also experiences a significant reduction as commonly observed in the vicinity of a magnetic quantum critical point (QCP). Our results indicate that the stoichiometric RbGd2Fe4As4O2 at ambient pressure might be located near a QCP such that the enhanced critical spin fluctuations lead to high-T c superconductivity. The application of pressure should broaden the electronic bandwidth and weaken the spin fluctuations, and then restore a Fermi-liquid ground state with lower T c.

Pressure-induced enhancement of thermoelectric power factor in pristine and hole-doped SnSe crystals.

We evaluate the influence of pressure on the thermoelectric power factors PF ≡ S 2 σ of pristine and Na-doped SnSe crystals by measuring their electrical conductivity σ(T) and Seebeck coefficient S(T) up to ∼22 kbar with a self-clamped piston-cylinder cell. For both cases, σ(T) is enhanced while S(T) reduced with increasing pressure as expected, but their imbalanced variations lead to a monotonic enhancement of PF under pressure. For pristine SnSe, σ(290 K) increases by ∼4 times from ∼10.1 to 38 S cm-1, while S(290 K) decreases by only ∼12% from 474 to 415 µV K-1, leading to about three-fold enhancement of PF from 2.24 to 6.61 µW cm-1 K-2, which is very close to the optimal value of SnSe above the structural transition at ∼800 K at ambient pressure. In comparison, the PF of Na-doped SnSe at 290 K is enhanced moderately by ∼30% up to 20 kbar. In contrast, the PF of isostructural black phosphorus with a simple band structure was found to decrease under pressure. The comparison with black phosphorus indicates that the multi-valley valence band structure of SnSe is beneficial for the enhancement of PF by retaining a large Seebeck coefficient under pressure. Our results also provide experimental confirmation on the previous theoretical prediction that high pressure can be used to optimize the thermoelectric efficiency of SnSe.

Reemergence of high-Tc superconductivity in the (Li1-xFe x )OHFe1-ySe under high pressure.

In order to elucidate pressure-induced second superconducting phase (SC-II) in A x Fe2-ySe2 (A = K, Rb, Cs, and Tl) having an intrinsic phase separation, we perform a detailed high-pressure magnetotransport study on the isoelectronic, phase-pure (Li1-xFe x )OHFe1-ySe single crystals. Here we show that its ambient-pressure superconducting phase (SC-I) with a critical temperature Tc ≈ 40 K is suppressed gradually to below 2 K and an SC-II phase emerges above Pc ≈ 5 GPa with Tc increasing progressively to above 50 K up to 12.5 GPa. Our high-precision resistivity data uncover a sharp transition of the normal state from Fermi liquid for SC-I to non-Fermi liquid for SC-II phase. In addition, the reemergence of high-Tc SC-II is found to accompany with a concurrent enhancement of electron carrier density. Without structural transition below 10 GPa, the observed SC-II with enhanced carrier density should be ascribed to an electronic origin presumably associated with pressure-induced Fermi surface reconstruction.