Characteristics of children with IgA nephropathy.

BACKGROUND: We analyzed the demographic and clinical characteristics of children with immunoglobulin A (IgA) nephropathy using data in the first pages of electronic health records of 22 hospitals from 2016 to 2018. METHODS: Information collected included gender, age, infection site, etiological infection, acute kidney injury (AKI), and chronic kidney disease (CKD) stages 2-5. We analyzed the gender and age distribution of children with IgA nephropathy, the characteristics of children complicated with AKI and CKD, and the influence of geographical distribution and economic status on the incidence of IgA nephropathy. RESULTS: We included a total of 4006 patients with IgA nephropathy. Incidence in males gradually increased with age. Seventy-nine cases (1.97%) had AKI. We found no significant difference in gender (P = 0.19) or age (P = 0.07) between the AKI and non-AKI groups. Twenty-nine patients had CKD (0.72%), who were significantly older than those in the non-CKD group (P < 0.0001). The incidence of IgA nephropathy in less-developed areas was significantly lower than that in developed areas (P = 0.0002). CONCLUSIONS: The incidence of IgA nephropathy was high mainly in males. Age was an important factor affecting CKD. The disease was related to environment and economic status. IMPACT: We analyze the demographic and clinical characteristics of children with immunoglobulin A (IgA) nephropathy using data in the first pages of electronic health records. This is a large sample, multi-center study. The incidence of IgA nephropathy in males increased gradually with age. Age was an important factor affecting CKD. The disease was related to environment and economic status.

Berry-Phase Switch in Electrostatically Confined Topological Surface States.

Here, we visualize the trapping of topological surface states in the circular n-p junctions on the top surface of the seven-quintuple-layer three dimensional (3D) topological insulator (TI) Sb_{2}Te_{3} epitaxial films. As shown by spatially dependent and field-dependent tunneling spectra, these trapped resonances show field-induced splittings between the degenerate time-reversal-symmetric states at zero magnetic field. These behaviors are attributed unambiguously to Berry-phase switch by comparing the experimental data with both numerical and semiclassical simulations. The successful electrostatic trapping of topological surface states in epitaxial films and the observation of Berry-phase switch provide a rich platform of exploiting new ideas for TI-based quantum devices.

Generation of a human iPSC line from a Bardet-Biedl syndrome patient compound heterozygous for the BBS7 variants c.849 + 1G > C/c.754G > A.

Bardet-Biedl syndrome (BBS) is primarily a multisystem nonmotile ciliopathy. In this study, we describe the successful establishment and characterization of an iPSC line from a patient diagnosed with BBS who was compound heterozygous for the BBS7 variants c.849 + 1G > C (splicing) and c.754G > A (p.D252N).

Selective trapping of hexagonally warped topological surface states in a triangular quantum corral.

The surface of a three-dimensional topological insulator (TI) hosts two-dimensional massless Dirac fermions (DFs), the gapless and spin-helical nature of which leads to their high transmission through surface defects or potential barriers. Here, we report the behaviors of topological surface states (TSS) in a triangular quantum corral (TQC) which, unlike a circular corral, is supposed to be totally transparent for DFs. By real-space mapping of the electronic structure of TQCs, both the trapping and detrapping behaviors of the TSS are observed. The selection rules are found to be governed by the geometry and spin texture of the constant energy contour of TSS upon the strong hexagonal warping in Bi2Te3. Our work indicates the extended nature of TSS and elucidates the selection rules of the trapping of TSS in the presence of a complicated surface state structure, giving insights into the effective engineering of DFs in TIs.

Nutrition imbalance in Chinese chronic kidney disease children.

BACKGROUND: Nutrition imbalance is common in chronic kidney disease (CKD) children. This study evaluated the nutrition status of CKD children at different stages using bioimpedance analysis (BIA) compared with anthropometry. METHODS: Fifty-five CKD children at stages III, IV, V and 19 age- and sex-matched healthy controls were recruited. Fat, protein and mineral composition on BIA were analyzed together with anthropometry for height, weight and body mass index (BMI). Biochemistry was also checked in CKD children. RESULTS: Of the CKD children, 23.6%, 10.9% and 56.3% were underweight, overweight/obese and stunted, respectively. On BIA, 52.7%, 70.9%, 14.5% and 40.0% of the CKD children had protein reduction, fat reduction, fat enhancement and mineral reduction, respectively. Growth retardation and nutrition reduction became remarkable at stages IV and V. Approximately 65% of healthy-weight children had nutrition reduction. In the underweight and healthy-weight groups, fat reduction rates were higher than protein reduction rate. In the overweight/obese group, fat enhancement was most notable. Mineral reduction was less remarkable. CONCLUSIONS: The nutrition imbalance in CKD children on BIA correlated well with anthropometry and disease process, supporting BIA as an auxiliary diagnosis tool.

Urinary CD80 excretion is a predictor of good outcome in children with primary nephrotic syndrome.

BACKGROUND: The level of urinary cluster of differentiation 80 (uCD80) is elevated in most children with minimal change disease (MCD) as opposed to focal segmental glomerulosclerosis (FSGS) during the acute phase. The objective of this follow-up study was to evaluate whether uCD80 elevation is actually associated with MCD and whether it signals better prognosis. METHODS: We evaluated uCD80 levels and a series of putative progression factors in a cohort of 64 patients with nephrotic syndrome (NS) seen between 2011 and 2016. We monitored progression of chronic kidney disease (CKD), assessed as a glomerular filtration rate of < 90 ml/min/1.73 m2 for at least 3 months. Patients were classified according to uCD80 level and to the progression rate as calculated by Kaplan-Meier survival analysis and Cox's regression analysis. RESULTS: During a mean follow-up period of 4.8 ± 0.6 (range 3.5-6.0) years, 13 children (20%) evolved to at least CKD stage 2. The 64 patients with NS and normal baseline renal function were divided into two groups based on uCD80 excretion, i.e. below or above a defined cutoff (< or > 328.98 ng/g creatinine). The predicted response to immunosuppression therapy was 34.5 and 100% in the low- and high-uCD80 excretion, respectively (p < 0.001). Progression to CKD was 41.4 vs. 2.9% in NS patients (p < 0.001). Using the Cox model, only uCD80 excretion (p = 0.013, relative risk 6.171) predicted progression to CKD. CONCLUSIONS: Urinary CD80 predicts progression and remission in children with NS. The use of uCD80 as a prognostic marker facilitates the identification of high-risk patients at an early stage and may lead to better treatment selection.

[An assessment of nutritional status in children on maintenance hemodialysis due to stage 5 chronic kidney disease].

OBJECTIVE: To investigate the nutritional status of children on maintenance hemodialysis due to stage 5 chronic kidney disease (CKD) and the clinical significance of nutritional assessment indices. METHODS: A total of 21 children on maintenance hemodialysis due to stage 5 CKD were grouped according to body mass index. The nutritional status was assessed based on anthropometric parameters, biochemical parameters, inflammatory factors, residual renal function, indices of dialysis adequacy, and resting energy expenditure. Related indices were compared between the children with malnutrition and those with normal nutritional status. RESULTS: Of the 21 children, 10 had malnutrition and 11 had normal nutritional status. There were significant differences between the two groups in anthropometric parameters, levels of leptin, insulin-like growth factor-1, interleukin-1, interleukin-6, and tumor necrosis factor-α, and mean 24-hour residual urine volume (P<0.05), while there were no significant differences in albumin, prealbumin, CONCLUSIONS: urea clearance index (Kt/V), and measured resting energy expenditure. CONCLUSIONS: Anthropometric parameters, biochemical parameters, residual renal function, and inflammatory factors have an important value in evaluating the nutritional status of children with stage 5 CKD on maintenance hemodialysis. Further studies are needed to investigate the value of the measurement of resting energy expenditure in the evaluation and monitoring of nutritional status in children with stage 5 CKD on maintenance hemodialysis.

Charge ordering in the electron-doped superconductor Nd(2-x)Ce(x)CuO4.

In cuprate high-temperature superconductors, an antiferromagnetic Mott insulating state can be destabilized toward unconventional superconductivity by either hole or electron doping. In hole-doped (p-type) cuprates, a charge ordering (CO) instability competes with superconductivity inside the pseudogap state. We report resonant x-ray scattering measurements that demonstrate the presence of charge ordering in the n-type cuprate Nd(2-x)Ce(x)CuO4 near optimal doping. We find that the CO in Nd(2-x)Ce(x)CuO4 occurs with similar periodicity, and along the same direction, as in p-type cuprates. However, in contrast to the latter, the CO onset in Nd(2-x)Ce(x)CuO4 is higher than the pseudogap temperature, and is in the temperature range where antiferromagnetic fluctuations are first detected. Our discovery opens a parallel path to the study of CO and its relationship to antiferromagnetism and superconductivity.

Urinary CD80 levels as a diagnostic biomarker of minimal change disease.

BACKGROUND: Early diagnosis of minimal change disease (MCD) in nephrotic syndrome (NS) patients remains challenging. Doctors often make a diagnosis of MCD using invasive renal biopsy. CD80, a transmembrane protein, is present on podocytes in a number of experimental models of NS. Urinary CD80 levels are significantly elevated in MCD but not in focal segmental glomerulosclerosis (FSGS) or other glomerulopathies. The purpose of this study was to investigate the feasibility of using urinary CD80 levels as a biomarker for the diagnosis of MCD. MATERIALS AND METHODS: A total of 165 subjects, 129 men and 36 women, were enrolled in this study. Urinary samples were collected from 37 patients with MCD, 27 patients with FSGS, 30 patients with other glomerulopathies, and 71 healthy people. Using ELISA, experimental values were compared with those produced by kidney biopsy samples. RESULTS: The concentration of urinary CD80 was significantly higher in the active MCD group (689.66 ± 378.21 ng/g creatinine) than in the FSGS group (123.49 ± 167. 88 ng/g creatinine, P < 0.00), other glomerulopathies group (152.37 ± 220. 14 ng/g creatinine, P < 0.001) and the control group (81.83 ± 23.01 ng/g creatinine; P < 0.001). A cutoff value of 328.98 (ng/g creatinine) was proposed, with a sensitivity of 81.1 % and specificity of 94.4 %. The area under the receiver operating characteristic (ROC) curve for the urinary CD80 to diagnose MCD was 0.925 (95 % confidence interval: 0.873-0.978). CONCLUSIONS: This experiment has preliminarily confirmed urinary CD80 as a non-invasive diagnostic biomarker. It may have significant value in the diagnosis of MCD.

Imaging the electron-boson coupling in superconducting FeSe films using a scanning tunneling microscope.

Scanning tunneling spectroscopy has been used to reveal signatures of a bosonic mode in the local quasiparticle density of states of superconducting FeSe films. The mode appears below Tc as a "dip-hump" feature at energy Ω∼4.7kBTc beyond the superconducting gap Δ. Spectra on strained regions of the FeSe films reveal simultaneous decreases in Δ and Ω. This contrasts with all previous reports on other high-Tc superconductors, where Δ locally anticorrelates with Ω. A local strong coupling model is found to reconcile the discrepancy well, and to provide a unified picture of the electron-boson coupling in unconventional superconductors.

Survey of chronic haemodialysis in children between 2007 and 2012 in China.

AIM: The prevalence of chronic kidney disease (CKD) in children has been on the rise in China and more and more paediatric patients are now relying on chronic renal replacement therapies to sustain their lives. However, there is still a lack of literature in China about their outcomes, thus making it difficult, if not impossible for the paediatric nephrology community to develop strategies to guide future developments and to better serve this group of sick children. METHODS: Our institution has recently conducted a nation-wide survey to obtain data of children with end-stage renal disease (ESRD) between the years 2007 to 2012. Questionnaires were distributed to 39 member hospitals of the Chinese Paediatric Nephrology Association. Only 28 of our member hospitals were actively providing dialysis services to children and their responses were included in this study. RESULTS: There were a total of 1033 children with ESRD and within this cohort, 474 patients (45.9%) received chronic dialysis and 380 patients (80.2%) preferred haemodialysis. CONCLUSION: Haemodialysis is far more commonly used than peritoneal dialysis in China and the outcomes were similar to the experiences in North America. The data we gained through this survey provides the foundation for future planning and development of the paediatric dialysis services in China.

Transareola single-site endoscopic thyroidectomy: clinical study of 28 cases with thyroid nodules.

OBJECTIVES: To investigate the feasibility and safety of transareola single-site endoscopic thyroidectomy. SUBJECTS AND METHODS: Twenty-eight patients with thyroid nodules were involved in this study. An incision was cut on a single areola, and a laparoendoscope apparatus and an operating apparatus were implanted. The thyroid gland was exposed using the neck suture suspension technique, and the damaged thyroid gland was removed with an ultrasonic scalpel. The operation time, intraoperative bleeding volume, postoperative pain score, and cosmetic satisfaction score were calculated. RESULTS: Unilateral subtotal thyroidectomy was performed in 12 cases, unilateral partial thyroidectomy in 14 cases, and bilateral partial thyroidectomy in 2 cases. For the former 14 cases, the operation time was 145-205 minutes, with a mean duration of 170 minutes; the operation time ranged from 125 to 150 minutes, with a mean of 135 minutes, for the latter 14 cases. The intraoperative bleeding volume was 15-40 mL, with a mean of 25 mL. The total postoperative wound drainage was 80-135 mL, with a mean of 110 mL. The drainage tube was removed 3-4 days after surgery. The visual analog scale score was 1-5 at 24 hours postoperatively, with a mean score of 3.10. Postoperative pathological examination diagnosed thyroid adenoma in 11 cases and nodular goiter in 17 cases. CONCLUSIONS: Transareola single-site endoscopic thyroidectomy is feasible and safe and has the advantages of a covert incision, small subcutaneous separation area, and high cosmetic satisfaction. The operation time shortens with the increasing number of patients undergoing operations.

Scanning tunneling microscopy of interface properties of Bi2Se3 on FeSe.

We investigate the heteroepitaxial growth of Bi(2)Se(3) films on FeSe substrates by low-temperature scanning tunneling microscopy/spectroscopy. The growth of Bi(2)Se(3) on FeSe proceeds via van der Waals epitaxy with atomically flat morphology. A striped moiré pattern originating from the lattice mismatch between Bi(2)Se(3) and FeSe is observed. Tunneling spectra reveal the spatially inhomogeneous electronic structure of the Bi(2)Se(3) thin films, which can be ascribed to the charge transfer at the interface.

Suppression of superconductivity by twin boundaries in FeSe.

Low-temperature scanning tunneling microscopy and spectroscopy are employed to investigate twin boundaries in stoichiometric FeSe films grown by molecular beam epitaxy. Twin boundaries can be unambiguously identified by imaging the 90° change in the orientation of local electronic dimers from Fe site impurities on either side. Twin boundaries run at approximately 45° to the Fe-Fe bond directions, and noticeably suppress the superconducting gap, in contrast with the recent experimental and theoretical findings in other iron pnictides. Furthermore, vortices appear to accumulate on twin boundaries, consistent with the degraded superconductivity there. The variation in superconductivity is likely caused by the increased Se height in the vicinity of twin boundaries, providing the first local evidence for the importance of this height to the mechanism of superconductivity.

Identification and analysis of mutations in WTX and WT1 genes in peripheral blood and tumor tissue of children with Wilms' tumor.

BACKGROUND: Wilms' tumor (nephroblastoma) is the most common pediatric kidney cancer. Only one Wilms' tumor gene is known, WT1 at 11p13, which is mutated in 5% - 10% of Wilms' tumors. Recently, mutations were reported in WTX at Xq11.1 in Wilms' tumors. This study investigated the mutation proportion, type, and distribution in WTX and WT1 in children with Wilms' tumor. The role of WTX/WT1 in the development of Wilms' tumor, and the relationship between clinical phenotype and genotype, were also studied. METHODS: Wilms' tumor specimens (blood samples from 70 patients and tumor tissue samples from 52 patients) were used. A long fragment of WTX and 10 exons and intron sequences of WT1 were amplified by polymerase chain reaction (PCR) from extracted genomic DNA and sequenced. A chi-square test compared the difference between the WTX mutation group and the no mutation group. The relationship between the mutations and clinical phenotype was analyzed. RESULTS: WTX mutations were found in 5/52 tumor tissues and in 2/70 peripheral blood samples (five cases in total, all point mutations). Two patients had a WTX mutation in both samples. WT1 mutations were found in 2/52 tumor tissues and in 4/70 peripheral blood samples (five cases in total, all point mutations). One patient had a WT1 mutation in both samples. Ten cases had WTX or WT1 mutation (19.2% of Wilms' tumors). No overlapping WTX and WT1 mutations were found. No significant differences in clinical parameters were found between patients with and without a WTX mutation. CONCLUSIONS: WTX mutations occur early in Wilms' tumor development, but at a low proportion. There was no evidence that WTX is the main cause of Wilms' tumor. Clinical parameters of patients with WTX mutations are not related to the mutation, indicating a limited impact of WTX on tumor progression. WTX and WT1 mutations occur independently, suggesting a relationship between their gene products.

Charge-transfer-induced cesium superlattices on graphene.

We investigate cesium (Cs) adsorption on graphene formed on a 6H-SiC(0001) substrate by a combined scanning tunneling microscopy and density functional theory study. Individual Cs atoms adsorb preferentially at the rim region of the well-defined 6×6 substrate superstructure and on multilayer graphene. By finely controlling the graphene thickness and Cs coverages (1/3 ML and 1 ML), we here demonstrate two intriguing and well-ordered Cs superlattices on bilayer and multilayer graphene (<6 layers). Statistical analysis of the Cs-Cs interatomic distance reveals a hitherto unobserved Cs-Cs long-range electrostatic potential caused by charge transfer from Cs to graphene, which couples with the inhomogeneous substrate potential to stabilize the observed Cs superlattices. The present study provides a new avenue to fabricate atomic and molecular superlattices for applications in high-density recording and data storage.

Fermi-level tuning of epitaxial Sb2Te3 thin films on graphene by regulating intrinsic defects and substrate transfer doping.

High-quality Sb2Te3 films are obtained by molecular beam epitaxy on a graphene substrate and investigated by in situ scanning tunneling microscopy and spectroscopy. Intrinsic defects responsible for the natural p-type conductivity of Sb2Te3 are identified to be the Sb vacancies and Sb(Te) antisites in agreement with first-principles calculations. By minimizing defect densities, coupled with a transfer doping by the graphene substrate, the Fermi level of Sb2Te3 thin films can be tuned over the entire range of the bulk band gap. This establishes the necessary condition to explore topological insulator behaviors near the Dirac point.

Landau quantization and the thickness limit of topological insulator thin films of Sb2Te3.

We report the experimental observation of Landau quantization of molecular beam epitaxy grown Sb{2}Te{3} thin films by a low-temperature scanning tunneling microscope. Different from all the reported systems, the Landau quantization in a Sb{2}Te{3} topological insulator is not sensitive to the intrinsic substitutional defects in the films. As a result, a nearly perfect linear energy dispersion of surface states as a 2D massless Dirac fermion system is achieved. We demonstrate that four quintuple layers are the thickness limit for a Sb{2}Te{3} thin film being a 3D topological insulator. The mechanism of the Landau-level broadening is discussed in terms of enhanced quasiparticle lifetime.

Direct observation and measurement of mobile charge carriers in a monolayer organic semiconductor on a dielectric substrate.

We report the electrical characterization of a single layer of an organic semiconductor grown on a dielectric surface. The dynamic response of the charge carriers in the monolayer film of pentacene was characterized through the electrostatic interactions between an electric force microscope (EFM) probe and pentacene islands of various sizes. These islands were formed in situ by segmenting a coalesced pentacene monolayer into separated regions. The size-dependent dielectric responses of the pentacene islands suggest that mobile charges exist in the organic monolayer. Local capacitance spectroscopy revealed that the charge carriers in the p-type pentacene monolayer could be depleted at high bias voltages, enabling a further determination of the charge-carrier concentration in the organic semiconductor ultrathin film.