DPSCs regulate epithelial-T cell interactions in oral submucous fibrosis

BACKGROUND

Oral submucous fibrosis (OSF) is a precancerous lesion characterized by fibrous tissue deposition, the incidence of which correlates positively with the frequency of betel nut chewing. Prolonged betel nut chewing can damage the integrity of the oral mucosal epithelium, leading to chronic inflammation and local immunological derangement. However, currently, the underlying cellular events driving fibrogenesis and dysfunction are incompletely understood, such that OSF has few treatment options with limited therapeutic effectiveness. Dental pulp stem cells (DPSCs) have been recognized for their anti-inflammatory and anti-fibrosis capabilities, making them promising candidates to treat a range of immune, inflammatory, and fibrotic diseases. However, the application of DPSCs in OSF is inconclusive. Therefore, this study aimed to explore the pathogenic mechanism of OSF and, based on this, to explore new treatment options.

METHODS

A human cell atlas of oral mucosal tissues was compiled using single-cell RNA sequencing to delve into the underlying mechanisms. Epithelial cells were reclustered to observe the heterogeneity of OSF epithelial cells and their communication with immune cells. The results were validated in vitro, in clinicopathological sections, and in animal models. In vivo, the therapeutic effect and mechanism of DPSCs were characterized by histological staining, immunohistochemical staining, scanning electron microscopy, and atomic force microscopy.

RESULTS

A unique epithelial cell population, Epi1.2, with proinflammatory and profibrotic functions, was predominantly found in OSF. Epi1.2 cells also induced the fibrotic process in fibroblasts by interacting with T cells through receptor-ligand crosstalk between macrophage migration inhibitory factor (MIF)-CD74 and C-X-C motif chemokine receptor 4 (CXCR4). Furthermore, we developed OSF animal models and simulated the clinical local injection process in the rat buccal mucosa using DPSCs to assess their therapeutic impact and mechanism. In the OSF rat model, DPSCs demonstrated superior therapeutic effects compared with the positive control (glucocorticoids), including reducing collagen deposition and promoting blood vessel regeneration. DPSCs mediated immune homeostasis primarily by regulating the numbers of KRT19 + MIF + epithelial cells and via epithelial-stromal crosstalk.

CONCLUSIONS

Given the current ambiguity surrounding the cause of OSF and the limited treatment options available, our study reveals that epithelial cells and their crosstalk with T cells play an important role in the mechanism of OSF and suggests the therapeutic promise of DPSCs.

[Study of the predictive role of serum HBV RNA on HBeAg serological conversion in children with chronic hepatitis B]

Objective: To investigate the role of serum hepatitis B virus RNA (HBV RNA) in predicting HBeAg serological conversion in children with chronic hepatitis B. Methods: 175 children aged 1~17 years with chronic hepatitis B who received interferon α (IFNα) for 48 weeks were selected. Patients were divided into HBeAg seroconversion and non-conversion based on whether HBeAg seroconversion occurred at 48 weeks of treatment.T-test and Mann-Whitney U test were used to compare between groups; chisquare test or Fisher exact probability method was used to compare the frequency between groups of classified variables; and Pearson correlation was used to analyze the correlation between indicators. Univariate and multivariate logistic regression analyses were used to identify influencing factors associated with HBeAg serological conversion. The predictive effect of HBV RNA, HBV DNA, and HBsAg on HBeAg serological conversion was compared and analyzed by the receiver operating characteristic curve (ROC). Results: The seroconversion rate of HBeAg at 48 weeks was 36.0% (63/175). The reduction in HBVRNA levels from baseline to the 12th, 24th, 36th, and 48th weeks of antiviral therapy was significantly greater in the HBeAg serological conversion group than that in the non-conversion group, and the difference was statistically significant between the two groups (P < 0.05). Univariate and multivariate regression analyses showed that age and a decline in HBV RNA levels at week 12 were independent predictors of HBeAg serological conversion. The area under the ROC curve (AUROC) of HBV RNA decline at week 12 was 0.677(95% CI∶0.549-0.806, P = 0.012), which was significantly better than the same period of AUROC of HBV DNA (0.657, 95% CI∶0.527-0.788, P = 0.025) and HBsAg (0.660, 95% CI∶0.526-0.795, P = 0.023) decline. HBV RNA levels decreased (>1.385 log10 copies/ml) at week 12, with a positive predictive value of 53.2%, a negative predictive value of 72.2%, a sensitivity of 77.4%, and a specificity of 57.9% for HBeAg seroconversion. Conclusion: HBV RNA level lowering during the 12th week of antiviral therapy can serve as an early predictor marker for HBeAg serological conversion in children with chronic hepatitis B.

Investigation on knowledge level about rational use of antimicrobial drugs among pharmacists in medical institutions in Shanxi province, China

OBJECTIVE

To investigate the pharmacist's knowledge about rational use of antimicrobials in Shanxi of China, so as to find out the problems and provide support for the management of antimicrobials.

METHODS

A questionnaire survey was conducted, which included the basic information of the respondents, the basic knowledge about antimicrobial management and the related knowledge about antimicrobial drugs. SPSS 25.0 was used for statistical analysis.

RESULTS

A total of 462 pharmacists were investigated. The average score of the knowledge related to rational use of antimicrobials was 10.49 ± 4.05. It showed that the hospital type, grade, pharmacist's education, professional title and years of experience had effect on the pharmacist's knowledge level about antimicrobial drugs (P < 0.05). Multivariable logistic regression analysis showed that hospital grade and pharmacist's education were the main influencing factors (P < 0.05).

CONCLUSION

Pharmacists have insufficient knowledge about the rational use of antibacterial drugs. It is essential to strengthen the training in management regulations and application of antibacterial drugs.

Identification and expression analysis of cobia (Rachycentron canadum) liver-related miRNAs under hypoxia stress

At present, due to the influence of global warming, seasonal change, diurnal variation, and eutrophication of the water body, hypoxia has become one of the major factors limiting the stable development of cobia (Rachycentron canadum) culture. In this study, the miRNAs involved in hypoxia stress were screened, and the target genes of miRNAs were annotated and analyzed. The results showed that a total of 184 conservative microRNA (miRNA) and 121 newly predicted miRNA were obtained by sequencing the liver of control (C) and hypoxic (dissolved oxygen, DO (2.64 ± 0.25) mg/L; 3 h) (S) groups. The pathways involved in energy metabolism included starch and sucrose metabolism (ko00500), glycosaminoglycan degradation (ko00531), and galactose metabolism (ko00052). The results indicate that the body maintains physiological activities by regulating some important pathways at the transcriptional level under hypoxia stress, such as the conversion of aerobic metabolism and anaerobic metabolism, the reduction of energy consumption, and the promotion of red blood cell proliferation to maintain the homeostasis of the body.

Treatment Choice of Complete Distal Forearm Fractures in 8 to 14 Years Old Children

BACKGROUND

New surgical techniques have challenged traditional guidelines for nonsurgical treatment in pediatric and adolescent distal forearm fractures. This study was performed to compare outcomes and costs between closed reduction with percutaneous pinning (CRPP) and closed reduction with casting in the treatment of complete distal forearm fractures in children 8 to 14 years old.

METHODS

A retrospective cohort study was performed of 175 displaced distal forearm fractures treated with 2 different methods in the emergency department of a children's trauma center. One hundred and fourteen children were managed using CRPP. The remaining 61 were treated with closed reduction and casting. All patients had initial follow-up radiographs. The quality of reduction and the residual angulation in both the coronal and sagittal planes were recorded. Outcomes included the angulation after reduction, residual angulation at final follow-up, radiation exposure, total immobilization time, days absent from school, total costs, and postoperative complications.

RESULTS

The postreduction sagittal plane angulation was significantly lower in the CRPP group (P=0.037). While residual deformity between the groups at the 6-month final follow-up was not significantly different in either the sagittal or coronal planes (P=0.486, 0.726), patients in the nonoperative group received greater radiation than those in the operative group (P<0.001). Patients in the nonoperative group missed fewer classes and sustained lower costs (P<0.001, <0.001). The mean immobilization time in each group was not significantly different (31.4±4.4 vs. 32.8±5.9 d; P=0.227).

CONCLUSIONS

Although the postreduction quality was a little better and radiation exposure was less in the CRPP group, there was no difference between the 2 groups in angulation, total immobilization time, or complication rates after 6 months. The cost and time absent from school of patients in the nonoperative group was significantly lower than in the operative group. There is no clear advantage to CRPP treatment on outcomes. Therefore, closed reduction and casting is recommended in complete distal forearm fractures of children 8 to 14 years old.

LEVEL OF EVIDENCE

Level III-therapeutic study.

Open reduction and Herbert screw fixation of Pipkin type IV femoral head fracture in an adolescent: A case report

BACKGROUND

Femoral head fracture is extremely rare in children. This may be the youngest patient with femoral head fracture ever reported in the literature. There are few pediatric studies that focus on cases treated with open reduction via the modified Hardinge approach.

CASE SUMMARY

A 14-year-old female adolescent suffered a serious traffic accident when she was sitting on the back seat of a motorcycle. A pelvic radiograph and computed tomography revealed a proximal femoral fracture and slight acetabular rim fracture. This was diagnosed as a Pipkin type IV femoral head fracture. An open reduction and Herbert screw fixation was performed via a modified Hardinge approach. After 1-year follow-up, the patient could walk without aid and participate in physical activities. The X-ray results showed that the fractures healed well with no evidence of complications.

CONCLUSION

Open reduction and Herbert screw fixation is an available therapy to treat Pipkin type IV femoral head fractures in children.

miR-143 is implicated in growth plate injury by targeting IHH in precartilaginous stem cells

Precartilaginous stem cells (PCSCs) are able to initiate chondrocyte and bone development. The present study aimed to investigate the role of miR-143 and the underlying mechanisms involved in PCSC proliferation. In a rat growth plate injury model, tissue from the injury site was collected and the expression of miR-143 and its potential targets was determined. PCSCs were isolated from the rabbits' distal epiphyseal growth plate. Cell viability, DNA synthesis, and apoptosis were determined with MTT, BrdU, and flow cytometric analysis, respectively. Real time PCR and western blot were performed to detect the mRNA and protein expression of the indicated genes. Indian hedgehog (IHH) was identified as a target gene for miR-143 with luciferase reporter assay. Decreased expression of miR-143 and increased expression of IHH gene were observed in the growth plate after injury. miR-143 mimics decreased cell viability and DNA synthesis and promoted apoptosis of PCSCs. Conversely, siRNA-mediated inhibition of miR-143 led to increased growth and suppressed apoptosis of PCSCs. Transfection of miR-143 decreased luciferase activity of wild-type IHH but had no effect when the 3'-UTR of IHH was mutated. Furthermore, the effect of miR-143 overexpression was neutralized by overexpression of IHH. Our study showed that miR-143 is involved in growth plate behavior and regulates PCSC growth by targeting IHH, suggesting that miR-143 may serve as a novel target for PCSC-related diseases.

[Studies on the role of chromobox protein homolog 2 in the inhibition of progression of hepatoma]

Objective: To explore chromobox protein homolog 2 (CBX2) expressions in relation to clinical features of patients and elucidate its role in the progression of hepatocellular carcinoma. Methods: Using the Cancer Genome Atlas (TCGA) database, R language was used to analyze the distribution of differentially expressed mRNA in hepatocellular carcinoma. The different expression of CBX2 in HCC and adjacent tissues and its relationship with survival and clinical characteristics of patients were further analyzed. The expression of CBX2 in liver tissues, liver cancer tissue, and L02, HepG2 and SMMC-7721 cell lines was detected by real time-PCR and western blot. The expression of CBX2 was interfered by siRNA in hepatoma cell line. MTT, colony formation, transwell assays, and flow cytometry were used to identify the proliferation, apoptosis, invasion and clone-formation ability of HepG2 and SMMC-7721 cells after CBX2 down-regulation. According to the different data, t-test, ANOVA, chi-square test, and COX regression model were used for statistical analysis. Survival curve was plotted through Kaplan-Meier method. Results: TCGA public database analysis showed that the expression of CBX2 mRNA in hepatocellular carcinoma tissues (7.296 ± 1.6115) was significantly higher than normal liver tissues (4.706 ± 0.940) (P = 0.000). In addition, the overall survival time of patients with low CBX2 mRNA expression was significantly longer than that of patients with high CBX2 mRNA expression [(5.971 ± 0.411) years vs. (4.650 ± 0.503) years, P = 0.001]. The expression level of CBX2 mRNA was correlated with the pathological TNM stage (P = 0.025) and differentiation degree (P < 0.001) of liver cancer. COX regression analysis showed that CBX2 mRNA expression was an independent predictor of patient survival (P = 0.013). siRNA was transfected and compared with the blank control group. The transgenic ability of HepG2 and SMMC-77221 cells decreased significantly at 72h (P < 0.05) and 96h (P < 0.05), and the apoptosis rate (11.430% ± 0.215%) was higher than blank control group (6.6 00% ± 0.170%) (P = 0.003). The number of invasive cells ((both P < 0.05) and relative colony forming cells ((both P < 0.001) were significantly decreased. In 20 cases of tissue samples, the expression of CBX2 protein (relative expression level 3.020 ± 0.269) in liver cancer was higher than that in adjacent tissues (relative expression level 0.886±0.065) (P < 0.001). The overall survival time of patients with low CBX2 expression in liver cancer was longer than that of patients with high expression [(3.670 + 0.576) years vs. (0.834 + 0.153) years, P = 0.004]. Conclusion: An evident high expression of CBX2 is an independent poor prognostic factor in hepatoma. Down-regulation of CBX2 expression can inhibit the progression of liver cancer. Therefore, CBX2 may be a prognostic biomarker and a new target for HCC treatment.

Whole genome sequencing of pairwise human subjects reveals DNA mutations specific to developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a common congenital malformation characterized by mismatch in shape between the femoral head and acetabulum, and leads to hip dysplasia. To date, the pathogenesis of DDH is poorly understood and may involve multiple factors, including genetic predisposition. However, comprehensive genetic analysis has not been applied to investigate a genetic component of DDH. In the present study, 10 pairs of healthy fathers and DDH daughters were enrolled to identify genetic hallmarks of DDH using high throughput whole genome sequencing. The DDH-specific DNA mutations were found in each patient. Overall 1344 genes contained DDH-specific mutations. Functional enrichment analysis showed that these genes played important roles in the cytoskeleton, microtubule cytoskeleton, sarcoplasm and microtubule associated complex. These functions affected osteoblast and osteoclast development. Therefore, we proposed that the DDH-specific mutations might affect bone development, and caused DDH. Our pairwise high throughput sequencing results comprehensively delineated genetic hallmarks of DDH. Further research into the biological impact of these mutations may inform the development of DDH diagnostic tools and allow neonatal gene screening.

[Analysis and discussion of risk factors related to dental implant failure]

The implant prosthesis has been extensively used in clinic recently, and implant failure is appearing. Many factors may cause the failure, and they work together generally. This paper summarizes and analyzes the failure cases related to implant treatment and relevant risk factors of oral implants in Department of Implantation, School of Stomatology, The Fourth Military Medical University during the past six years, in order to improve the success rate of implant prosthesis and provide guidance for clinical application.

From single atoms to self-assembled quantum single-atomic nanowires: noble metal atoms on black phosphorene monolayers

Transition metal (TM) nanostructures, such as one dimensional (1D) nanowires with/without substrates, usually possess drastically different properties from their bulk counterparts, due to their distinct stacking and electronic confinement. Correspondingly, it is of great importance to establish the dominant driving force in forming 1D single-metal-atom-wires (SMAWs). Here, with first-principles calculations, taking the black phosphorene (BP) monolayer as a prototype 2D substrate, we investigate the energetic and kinetic properties of all the 5d-TM atoms on the 2D substrate to reveal the mechanism of formation of SMAWs. In contrast to other 5d- and 4d-TMs, noble metal elements Pd and Pt are found to prefer to grow along the trough in an atom-by-atom manner, self-assembling into SMAWs with a significant magic growth behavior. This is due to distinct binding energies and diffusion barriers along the trough, i.e., zig-zag direction, as compared to other directions of the BP. The present findings are valuable in the fabrication and modulation of 1D nanostructures which can be anticipated to possess desirable functionalities for potential applications such as in nanocatalysis, nanosensors, and related areas.

Substrate co-doping modulates electronic metal-support interactions and significantly enhances single-atom catalysis

Transitional metal nanoparticles or atoms deposited on appropriate substrates can lead to highly economical, efficient, and selective catalysis. One of the greatest challenges is to control the electronic metal-support interactions (EMSI) between the supported metal atoms and the substrate so as to optimize their catalytic performance. Here, from first-principles calculations, we show that an otherwise inactive Pd single adatom on TiO₂(110) can be tuned into a highly effective catalyst, e.g. for O₂ adsorption and CO oxidation, by purposefully selected metal-nonmetal co-dopant pairs in the substrate. Such an effect is proved here to result unambiguously from a significantly enhanced EMSI. A nearly linear correlation is noted between the strength of the EMSI and the activation of the adsorbed O₂ molecule, as well as the energy barrier for CO oxidation. Particularly, the enhanced EMSI shifts the frontier orbital of the deposited Pd atom upward and largely enhances the hybridization and charge transfer between the O₂ molecule and the Pd atom. Upon co-doping, the activation barrier for CO oxidation on the Pd monomer is also reduced to a level comparable to that on the Pd dimer which was experimentally reported to be highly efficient for CO oxidation. The present findings provide new insights into the understanding of the EMSI in heterogeneous catalysis and can open new avenues to design and fabricate cost-effective single-atom-sized and/or nanometer-sized catalysts.

Relative edge energy in the stability of transition metal nanoclusters of different motifs

When a structure is reduced to a nanometer scale, the proportion of the edge atoms increases significantly, which can play a crucial role in determining both their geometric and electronic properties, as demonstrated by the recently established generalized Wulff construction principle [S. F. Li, et al., Phys. Rev. Lett., 2013, 111, 115501]. Consequently, it is of great interest to clarify quantitatively the role of the edge atoms that dominate the motifs of these nanostructures. In principle, establishing an effective method valid for determining the absolute value of the surface energy and particularly the edge energy for a given nanostructure is expected to resolve such a problem. However, hitherto, it is difficult to obtain the absolute edge energy of transition metal clusters, particularly when their sizes approach the nanometer regime. In this paper, taking Ru nanoclusters as a prototypical example, our first-principles calculations introduce the concept of relative edge energy (REE), reflecting the net edge atom effect over the surface (facet) atom effect, which is fairly powerful to quasi-quantitatively estimate the critical size at which the crossover occurs between different configurations of a given motif, such as from an icosahedron to an fcc nanocrystal. By contrast, the bulk effect should be re-considered to rationalize the power of the REE in predicting the relative stability of larger nanostructures between different motifs, such as fcc-like and hcp-like nanocrystals.

Treatment of Severely Displaced Radial Neck Fractures in Children With Percutaneous K-wire Leverage and Closed Intramedullary Pinning

To evaluate the efficacy and safety of percutaneous K-wire leverage (PKWL) reduction and closed intramedullary pinning (CIMP) for the treatment of pediatric radial neck fractures. From June 2010 to December 2013, a total of 50 children with Judet III and IV radial neck fractures were treated at our hospital. Manual closed reduction was first attempted to reduce the radial neck fractures. Upon successful closed reduction or the radial neck-shaft angle was reduced to <45°, radial intramedullary pinning or CIMP was performed for fixation. Unsuccessful manual reduction was corrected using percutaneous K-wire leverage and CIMP. The injured arm was fixed at the functional position using plaster for 4 to 6 weeks. Sixteen patients were treated with manual closed reduction and CIMP (group A). Percutaneous K-wire leverage and CIMP were performed for 30 patients (group B). Another 4 patients were treated with open reduction and CIMP (group C). Groups B and C showed no significant difference in the radial neck-shaft angle, fracture displacement, and angle/displace ratio (P > 0.05), but were significantly larger than group A in the radial neck-shaft angle and fracture displacement (P < 0.05). Group A and B had significantly shorter operation time than group C (58.4 ± 14.5 minutes, 55.2 ± 11.2 minutes, versus 81.4 ± 7.5 minutes, P < 0.05). Forty-five patients were followed up for a mean of 2 years. Bone union was achieved in all patients within a mean time of 4.1 months. The patients treated with manual reduction or percutaneous leverage reduction showed excellent results. Three patients, however, treated with open reduction showed 10 to 20° limitation in range of motion of the elbow. No other complications were seen. Percutaneous K-wire leverage and CIMP are safe and effective for the treatment of pediatric Judet III and IV radial neck fractures.

Silencing FKBP38 gene by siRNA induces activation of mTOR signaling in goat fetal fibroblasts

FKBP38 (also known as FKBP8) is a unique member of the FK506-binding protein (FKBP) family, and its role is controversial because it acts as an upstream regulator of the mTOR signaling pathway, which controls cell growth, proliferation, and differentiation. This study aimed to explore the role of FKBP38 in the activation of mTOR signaling in Cashmere goat (Capra hircus) fetal fibroblasts. To construct a Cashmere goat FKBP38 siRNA eukaryotic expression vector that targets FKBP38 mRNA, we designed shRNA based on the gene sequence deposited in GenBank (accession No. JF714970) and synthesized a DNA fragment encoding the shRNA. The DNA fragment was inserted into the pRNAT-U6.1/Neo vector to construct an expression vector of shRNA, which was labeled pRNAT-FKBP38-shRNA. The recombinant plasmid was used to transfect Cashmere goat fetal fibroblasts (GFb) using lipofectamine™2000. We found that cells were successfully transfected with pRNAT-U6.1/Neo-FKBP38-shRNA. Green fluorescence could be observed in cells following 48-h transfection. Proteins were then isolated from GFbs transfected with pRNAT-FKBP38-shRNA and from control cells, and protein expression was analyzed by western blot. Expression of FKBP38 decreased and mTOR signaling was activated, which induced the phosphorylation of mTOR, S6, and 4EBP1. Thus, FKBP38 gene-silencing activates mTOR signaling in goat cells.

Specific lignin accumulation in granulated juice sacs of Citrus maxima

Juice sac granulation occurring in pummelo fruits [Citrus maxima (Burm.) Merr.] is an undesirable trait, and the underlying mechanism remains unresolved. Previous studies have shown that lignin metabolism is closely associated with the process of juice sac granulation. Here, a method suitable for lignin isolation from pummelo tissues is established. Acetylated lignins from different pummelo tissues and cultivars were analyzed by HSQC NMR. The results showed that lignins in granulated juice sacs were characterized by an extremely high abundance of guaiacyl units (91.13-96.82%), in contrast to lignins from other tissues, including leaves, stems, and segment membranes. The abnormally accumulated lignins in granulated juice sacs were specific and mainly polymerized from coniferyl alcohol. No significant difference was found in lignin types among various cultivars. These findings indicated that the mechanism of juice sac granulation might be similar among various cultivars, although very different degrees of juice sac granulation can be observed.

Cloning of NAD-SDH cDNA from plum fruit and its expression and characterization

A full-length cDNA consisting of 1444 bp for NAD dependent sorbitol dehydrogenase (NAD-SDH) was cloned from fruit of plum (Prunus salicina var. cordata cv. Younai) by means of RT-PCR and RACE. The cDNA containing an open reading frame (ORF) of 1101 bp encoded a polypeptide of 367 amino acid residues. The maltose binding protein fusion SDH (MBP-SDH) was expressed and partially purified from Escherichia coli cells, and biochemical properties of MBP-SDH and SDH cleaved from the fusion protein by factor Xa were characterized. The MBP-SDH had the specific affinity for NAD and was able to oxidize sorbitol, xylitol, l-ribitol and mannitol but not ethyl alcohol, arabitol and other polyols. The optimum pH for the oxidation of sorbitol and the reduction of fructose was 9.0 and 7.0, respectively; the maximum reaction rate occurred when temperature increased up to 50 °C in the presence of sorbitol. The MBP-SDH with a subunit of 80 kDa appears to be a hexamer. Its molecular weight was 478.6 kDa estimated by gel filtration and 493.2 kDa estimated using native linear gradient PAGE. The K(m) values for sorbitol, NAD, fructose and NADH were 95.86 mM, 0.31 mM, 1.04 M and 0.038 mM, respectively. However, when MBP was cleaved from the fusion enzyme, the SDH exists as a homotetramer with the native molecular weight of 164.8 kDa estimated by gel filtration. The K(m) values were 111.8 mM, 0.35 mM, 1.25 M and 0.048 mM for sorbitol, NAD, fructose and NADH, respectively. The MBP-SDH and the SDH were similar with respect to their kinetic characteristics despite their difference in quaternary structures.

Advances in computational studies of energy materials

We review recent developments and applications of computational modelling techniques in the field of materials for energy technologies including hydrogen production and storage, energy storage and conversion, and light absorption and emission. In addition, we present new work on an Sn2TiO4 photocatalyst containing an Sn(II) lone pair, new interatomic potential models for SrTiO3 and GaN, an exploration of defects in the kesterite/stannite-structured solar cell absorber Cu2ZnSnS4, and report details of the incorporation of hydrogen into Ag2O and Cu2O. Special attention is paid to the modelling of nanostructured systems, including ceria (CeO2, mixed Ce(x)O(y) and Ce2O3) and group 13 sesquioxides. We consider applications based on both interatomic potential and electronic structure methodologies; and we illustrate the increasingly quantitative and predictive nature of modelling in this field.

The formation of nanocrystallite bone-like apatite on chemically treated Ti-24Nd-4Zr-7.9Sn alloy

Ti-24Nd-4Zr-7.9Sn alloy with low elastic modulus and high strength is a great candidate for artificial biomaterials used in orthopedic and dental implants. In order to improve biocompatibility, a biomimetic process was employed to deposit a bone-like apatite nanocrystal coating on alloy. Analysis of the coatings showed that a net-like Na2TiO3 layer with about 100 nm in size was formed on Ti-24Nd-4Zr-7.9Sn treated by NaOH. Consequently, a carbonated apatite nanocrystal coating, namely bone-like apatite, was biomimetically deposited on Na2TiO3 layer, which has similar mineral composition to that of natural bone. The growth mechanism of bone-like layer is also discussed.

Fabrication of porous titanium scaffold materials by a fugitive filler method

A clean powder metallurgy route was developed here to produce Ti foams, using a fugitive polymeric filler, polypropylene carbonate (PPC), to create porosities in a metal-polymer compact at the pre-processing stage. The as-produced foams were studied by scanning electron microscopy (SEM), LECO combustion analyses and X-ray diffraction (XRD). Compression tests were performed to assess their mechanical properties. The results show that titanium foams with open pores can be successfully produced by the method. The compressive strength and modulus of the foams decrease with an increasing level of porosity and can be tailored to those of the human bones. After alkali treatment and soaking in a simulated body fluid (SBF) for 3 days, a thin apatite layer was formed along the Ti foam surfaces, which provides favourable bioactive conditions for bone bonding and growth.

Oxidation investigation of nickel nanoparticles

This work reported an experimental investigation of complete oxidation of nickel nanoparticles using simultaneous thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Nickel nanoparticles and their elemental compositions were characterized by Brunauer-Emmett-Teller (BET) analysis, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The oxidation experiments were performed under isoconversion conditions for seven heating rates, varying from 2 to 20 K min(-1), with temperatures up to 1000 degrees C. The experiments revealed unique oxidation behaviour of nickel at the nanometre scale, such as early oxidation and melting phenomena, variable activation energies and different oxidation kinetics between low and high conversion ratios. Unlike its bulk counterpart where the activation energy is a constant, the activation energy of nickel nanoparticles depended on the conversion ratio, ranging between 1.4 and 1.8 eV. The oxidation kinetics of nickel nanoparticles changed from the classical diffusion controlled mechanism to a pseudo-homogeneous reaction as conversion ratios were over 50%. The oxidation mechanisms of nickel nanoparticles were further discussed and future studies to enhance understanding were identified.

Raman frequency shift in oxygen-functionalized carbon nanotubes

Based on density functional theory, the geometrical and electronic structures of oxygen-functionalized single-wall carbon nanotubes (O-SWCNs) are obtained, of which the vibrational properties are calculated in terms of lattice dynamics theory. Both bond expansion and contraction are found to coexist in O-SWCNs. A distinct Raman shift is observed in the radial breathing mode (RBM) and the G modes, depending not only on the tube diameter and chirality but also on oxygen coverage and adsorption configurations. With the oxygen coverage increasing, interestingly, a nonmonotonic upshift and downshift is observed in the G modes, which is attributed to the competition between the bond expansion and contraction. In addition, the resonance Raman effect at different oxygen coverage, which may be observable in O-SWCNs, is discussed.

Lattice Dynamics of Carbon Chain Inside a Carbon Nanotube

Based on the density functional theory, we obtain the optimum geometry of carbon chain inside a carbon nanotube. The phonon spectrum and specific heat of such a chain and nanotube hybrid system are calculated in terms of lattice dynamics theory. Some new phonon branches that have been obtained come from the coupling vibrations of the nanotube and the chain. The bending and stretching modes of the chain appear at about 520 cm(-1)and 1935 cm(-1) at Gamma point, respectively. It is found that the softening of G modes results mainly from the chain induced variations in the bond length on nanotube, independent of van der Waals interaction, while the stiffening of radial breathing mode is developed by the competition between the two factors. In the low-frequency region, the vibrational density of states are very different from that of the bare nanotube. Its specific heat implies the underlying quantized phonon structures and much large thermal conductivity in the hybrid system. In addition, the chain-length dependent vibration modes are calculated, from which it is expected that a finite chain of about 14 carbon atoms in the nanotube may produce the experimental Raman peak at about 1850 cm(-1).

A First-Principles Study of the Electronic Structure and Stability of a Lithium Aluminum Hydride for Hydrogen Storage

LiAlH4 holds great promise for reversible hydrogen storage, where a fundamental understanding of hydrogen interaction with the metal elements is essential to further improve its properties. The present paper reports a first-principles study of its stability and electronic structure, using a full potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation (GGA) for high accuracy. The theoretically calculated heat of formation agrees well with experiment. The electronic structures show that the H atoms bond nonequivalently with the Al in the [AlH4]- ligand, which leads to complex dehydrogenation characteristics of LiAlH4.

Metal organic chemical vapour deposition (MOCVD) of bone mineral like carbonated hydroxyapatite coatingsElectronic supplementary information (ESI) available: experimental data. See http://www.rsc.org/suppdata/cc/b3/b312855p/

For the first time, the MOCVD technique has been used to deposit carbonated hydroxyapatite onto Ti6AL4V substrates using volatile monomeric (liquid) complexes [Ca(beta-diketonate)(2)(L)] and P(OEt)(3).

[The software design for the molecular biological image processing system]

With the use of Visual Basic 6.0 language and molecular biological technology, we have developed a new molecular biological information processing system to detect the characteristic parameter of molecular biological electrophoresis image. The software can determine the molecular weight of the restriction endonuclease hydrolytic DNA fragment and protein or other macromolecules. The application indicates that the system with its accuracy reliability high efficiency and a large capacity of data to be stored, It is very useful to gene diagnosis and molecular biological researches.

[Production of u-PA with rCHO cell culture on porous microcarriers in serum-free growth medium]

A novel technique was developed to deal with apoptosis in large-scale animal cell culture. By means of replacing part of Cytopore porous microcarriers at regular intervals, a rCHO cell line, which produces urokinase-type plasminogen activitor(u-PA), was cultivated continuously with serum-free medium in a 30 L stirred tank for 91 days. The cell density was maintained at (1.3-2.6) x 10(7)/mL, and > 90% of cells was viable. In order to reduce the effect of cell density on cell growth and expression, a cyclic pressure oscillation was exerted on a 7.5 L reactor headspace to enhance cell expression at high cell density to a certain extent. During the 67 days of medium-replacement culture, the maximal cell density reached 2.64 x 10(7)/mL, and cell viability was always kept above 95% when combined with microcarrier-replacement. Compare to control culture, culture with cyclic pressure oscillation could enhance cell expression level and reduce the ratio of glucose metabolized anaerobically to produce lactate. With four-step purification process, about 80 g u-PA(approximately 90% scu-PA) was recovered from approximately 2100 liters supernatant which contained approximately 135 g u-PA.

[Expression of prourokinase in different mammalian cells]

Comparison studies of recombinant prourokinase(pro-UK) in various host cells, and expression vectors were carried out. Expression levels of vectors constructed in this study in different cell lines were compared. Mammalian cells expressing pro-UK were established. The levels of pro-UK expression in recombinant Namalwa, Vero and Sp2/0 cells are 200, 12.5 and 50 IU/(10(6) cells 24 h). pro-UK purities separated by immunoaffinity chromatograph are above 90%. Immunoabsorbent assay showed the ratio of pro-UK in CHO cells is lower than that from Vero and Namalwa cells. This study provide new host cells for pro-UK production.

A highly sensitive assay for protein using resonance light-scattering technique with dibromohydroxyphenylfluorone-molybdenum(VI) complex

At pH 2.8 and in the presence of 0.090% p-octylpolyethyleneglycol phenylether, the resonance light-scattering (RLS) spectrum of molybdenum(VI) complex with dibromohydroxyphenylfluorone (DBHPF) has a sharp peak at 586 nm. If the micro protein coexists with Mo(VI) and DBHPF, the RLS intensity of the complex at 586 nm is significantly enhanced by protein due to the binding interaction between protein and DBHPF-Mo(VI) complex. Based on this a new assay for protein is described. The dynamic ranges for bovine and human serum albumins are both 0.05-0.75 mg l-1 with detection limits of 13 and 15 ng ml-1, respectively. Besides high sensitivity, the method is characterized by good reproducibility, rapidity of reaction, good stability of chemical system, commonality of spectrofluorometer, few coexisting substances, especially detergents. The determinations of diluted human serum and urine by this method give the results very close to these by the Coomassie brilliant blue G-250 colorimetry, with relative standard deviations of five duplicates of 1.8-2.5%.

[Clinical observation on treatment of 40 cases of apoplexy hemiplegia complicated shoulder-hand syndrome with electro-acupuncture]

The authors treated 40 cases of shoulder-hand syndrome of apoplexy hemiplegia with electro-acupuncture (EA) and filiform needle acupuncture (FNA) respectively. The results showed that EA had better results in treating hand back swelling, hand skin temperature elevating and the bending finger caused pain than that with FNA (P < 0.05). The finger joint and shoulder joint improvement (the functional scoring increased for 3 points or more) in EA was also better than that of FNA (P < 0.05). The total marked effective rate was higher in EA group (75%) than that in FNA (50%), P < 0.05). It suggested that EA produced rhythmic muscle contraction which had a "shoulder-hand pump" like action, and is significant in eliminating hand back swelling and preventing atrophy of hand muscles.

[Surgical treatment of laryngeal cancer]

From March 1974 to December 1982, 186 patients with laryngeal cancer were treated by operation alone in our hospital. In this series, the average age was 56.5 years. The sex ratio of male and female was 2.9:1. Total laryngectomy comprised 42%, partial laryngectomy 20.4% and postlaryngectomy reconstruction 37.6%. The 3 and 5 year survival rates were 75% and 74% for glottic cancer, 67% and 61% for supraglottic cancer, 67% and 67% for infraglottic cancer, 70% and 38% for transglottic cancer. The authors believe that, at present, operation is the main method of treatment. For early laryngeal cancer, partial laryngectomy is indicated for better postoperative functions in addition to higher survival rate. In advanced laryngeal cancer, total laryngectomy and other radical operation as well as combined therapy are advocated.