A stable atmospheric-pressure plasma for extreme-temperature synthesis

Plasmas can generate ultra-high-temperature reactive environments that can be used for the synthesis and processing of a wide range of materials1,2. However, the limited volume, instability and non-uniformity of plasmas have made it challenging to scalably manufacture bulk, high-temperature materials3-8. Here we present a plasma set-up consisting of a pair of carbon-fibre-tip-enhanced electrodes that enable the generation of a uniform, ultra-high temperature and stable plasma (up to 8,000 K) at atmospheric pressure using a combination of vertically oriented long and short carbon fibres. The long carbon fibres initiate the plasma by micro-spark discharge at a low breakdown voltage, whereas the short carbon fibres coalesce the discharge into a volumetric and stable ultra-high-temperature plasma. As a proof of concept, we used this process to synthesize various extreme materials in seconds, including ultra-high-temperature ceramics (for example, hafnium carbonitride) and refractory metal alloys. Moreover, the carbon-fibre electrodes are highly flexible and can be shaped for various syntheses. This simple and practical plasma technology may help overcome the challenges in high-temperature synthesis and enable large-scale electrified plasma manufacturing powered by renewable electricity.

[Emphasis on multidisciplinary collaboration in clinical diagnosis and treatment of autoimmune disease-related ulcers]

The global prevalence and incidence of autoimmune diseases are increasing year by year, and the autoimmune diseases have become a major threat to public health. In the progression of the diseases, persistent and complex abnormal immune responses often lead to long-term unhealed skin ulcers, which not only affect the life quality of patients, but also lead to the aggravation of primary diseases. Therefore, doctors in burn surgery and other wound repair surgeries should pay attention to the understanding of autoimmune diseases. In the treatment of autoimmune disease-related ulcers, it is recommended to formulate a unified treatment plan according to the law of occurrence and development of the diseases, and multidisciplinary cooperation is needed to accelerate wound healing and improve the quality of wound healing.

Site-directed mutation of β-galactosidase from Streptococcus thermophilus for galactooligosaccharide-enriched yogurt making

β-Galactosidase is one of the most important enzymes used in dairy processing. It converts lactose into glucose and galactose, and also catalyzes galactose to form galactooligosaccharides (GOS), so-called prebiotics. However, most of the β-galactosidases from the starter cultures have low transgalactosylation activities, the process that results in galactose accumulation in yogurt. Here, a site-directed mutation strategy was attempted, to genetically modify β-galactosidase from Streptococcus thermophilus. Out of 28 Strep. thermophilus strains, a β-galactosidase gene named bgaQ, encoded for high β-galactosidase hydrolysis activity (BgaQ), was cloned from the strain Strep. thermophilus SDMCC050237. It was 3,081 bp in size, with 1,027 deduced amino acid residuals, which belonged to the GH2 family. After replacing the Tyr⁸⁰¹ and Pro⁸⁰² around the active sites of BgaQ with His⁸⁰¹ and Gly⁸⁰², the GOS synthesis of the generated mutant protein BgaQ-8012 increased from 20.5% to 26.7% at 5% lactose, and no hydrolysis activity altered obviously. Subsequently, the purified BgaQ or BgaQ-8012 was added to sterilized milk inoculated with 2 starters from Strep. thermophilus SDMCC050237 and Lactobacillus delbrueckii ssp. bulgaricus ATCC11842. The GOS yields with added BgaQ or BgaQ-8012 rose to 5.8 and 8.3 g/L, respectively, compared with a yield of 3.7 g/L without enzymes added. Meanwhile, the addition of the BgaQ or BgaQ-8012 reduced the lactose content by 49.3% and 54.4% in the fermented yogurt and shortened the curd time. Therefore, this study provided a site-directed mutation strategy for improvement of the transgalactosylation activity of β-galactosidase from Strep. thermophilus for GOS-enriched yogurt making.

Histone methyltransferase DOT1L coordinates AR and MYC stability in prostate cancer

The histone methyltransferase DOT1L methylates lysine 79 (K79) on histone H3 and is involved in Mixed Lineage Leukemia (MLL) fusion leukemogenesis; however, its role in prostate cancer (PCa) is undefined. Here we show that DOT1L is overexpressed in PCa and is associated with poor outcome. Genetic and chemical inhibition of DOT1L selectively impaired the viability of androgen receptor (AR)-positive PCa cells and organoids, including castration-resistant and enzalutamide-resistant cells. The sensitivity of AR-positive cells is due to a distal K79 methylation-marked enhancer in the MYC gene bound by AR and DOT1L not present in AR-negative cells. DOT1L inhibition leads to reduced MYC expression and upregulation of MYC-regulated E3 ubiquitin ligases HECTD4 and MYCBP2, which promote AR and MYC degradation. This leads to further repression of MYC in a negative feed forward manner. Thus DOT1L selectively regulates the tumorigenicity of AR-positive prostate cancer cells and is a promising therapeutic target for PCa.

Histone methyltransferase, DOTL1 is implicated in the pathogenesis of MLL-rearranged leukemia, however, not much is known of its role in prostate cancer (PCa). Here, the authors report that DOTL1 inhibition suppresses both androgen receptor and MYC pathways in a negative feed forward manner to reduce growth of AR-positive PCa.

A general method to synthesize and sinter bulk ceramics in seconds

Ceramics are an important class of materials with widespread applications because of their high thermal, mechanical, and chemical stability. Computational predictions based on first principles methods can be a valuable tool in accelerating materials discovery to develop improved ceramics. It is essential to experimentally confirm the material properties of such predictions. However, materials screening rates are limited by the long processing times and the poor compositional control from volatile element loss in conventional ceramic sintering techniques. To overcome these limitations, we developed an ultrafast high-temperature sintering (UHS) process for the fabrication of ceramic materials by radiative heating under an inert atmosphere. We provide several examples of the UHS process to demonstrate its potential utility and applications, including advancements in solid-state electrolytes, multicomponent structures, and high-throughput materials screening.

Population dynamics of Echinops gmelinii Turcz. at different successional stages of biological soil crusts in a temperate desert in China

The effects of biological soil crusts (BSC) on vascular plant growth can be positive, neutral or negative, and little information is available on the impacts of different BSC successional stages on vascular plant population dynamics. We analysed seedling emergence, survival, plant growth and reproduction in response to different BSC successional stages (i.e. habitats: bare soil, cyanobacteria, lichen and moss crusts) in natural populations of Echinops gmelinii Turcz. in the Tengger Desert of northwest China. The winter annual E. gmelinii is a dominant pioneer herb after sand stabilisation. During the early stages of BSC succession, the studied populations of E. gmelinii were characterised by high density, plant growth and fecundity. As the BSC succession proceeded beyond moss crusts, the fecundity decreased sharply, which limited seedling recruitment. Differences in seedling survival among the successional stages were not evident, indicating that BSC have little effect on survival in arid desert regions. Moreover, E. gmelinii biomass allocation exhibited low plasticity, and only reproductive allocation was sensitive to the various habitats. Our results further suggest that the negative effects of BSC succession on population dynamics are primarily driven by increasing topsoil water-holding capacity and decreasing rain water infiltration into deeper soil. We conclude that BSC succession drives population dynamics of E. gmelinii, primarily via its effect on soil moisture. The primary cause for E. gmelinii population decline during the moss-dominated stage of BSC succession is decreased fecundity of individual plants, with declining seed mass possibly reducing the success of seedling establishment.

[Female reproductive system dysplasia: a clinical study of 924 cases]

Objective: To explore the relationship between different types of female reproductive system dysplasia and age of visit, clinical manifestations, common types of combined malformations and endometriosis. Methods: The patient's medical records in the Second Hospital of Hebei Medical University from December 2002 to June 2016 were collected and retrospectively analyzed. Results: Among 924 cases of genital tract dysplasia, uterine dysplasia (65.3%, 824/1 261) was the most common, followed by vaginal dysplasia (28.3%, 357/1 261), hymen atresia and urogenital fistula (3.7%, 47/1 261), and cervical dysplasia (2.6%, 33/1 261). (1) The youngest age was in patients with hymen atresia and urogenital fistula, with a median of 14.5 years old, while the older age were in patients with uterine, vaginal and cervical dysplasia, with median age of 25.0, 24.0 and 23.0 years old, respectively. (2) The clinical manifestations were lack of specificity, mainly abnormal findings of physical examination or accessory examination, primary amenorrhea, lower abdominal pain, infertility, adverse pregnancy history. (3) About other systemic malformations, urological malformations were the most common (4.8%, 44/924), followed by spinal malformations (0.5%, 5/924), inguinal hernia (0.4%, 4/924), heart malformations (0.2%, 2/924), cleft lip and palate (0.2%, 2/924). Oblique vaginal septal syndrome and MRKH syndrome were the most likely to be associated with other system malformations. (4) About combination with endometriosis, there was no significant difference between obstructive genital tract malformations (2.3%, 9/385) and non obstructive genital tract malformations (1.7%, 9/539; P=0.469). Conclusions: Female reproductive system dysplasia is the most common in uterine dysplasia, followed by vaginal dysplasia, hymen atresia and urogenital fistula, and cervical dysplasia. The age of visit is generally older, often found by abnormal findings of physical examination or accessory examination, primary amenorrhea, lower abdominal pain, infertility, adverse pregnancy history;and could be combined with a variety of other system malformations, most seen by urinary system malformations,there is also the risk of endometriosis.

[Study on the super-antigen genes of group A Streptococcus pyogenes strains isolated from patients with scarlet fever and pharyngeal infection, in Beijing, 2015-2017]

Objective: To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS), isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. Methods: Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS. Eleven currently known SAg genes including SpeA, speC, speG, speH, speI, speJ, speK, speL, speM, smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR. Results: A total of 377 GAS were isolated from 6 801 throat swab specimens, with the positive rate as 5.5%. There were obvious changes noticed among speC, speG, speH and speK in three years. A total of 45 SAg genes profiles were observed, according to the SAgs inclusion. There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emm1 and emm12 strains (χ(2)=38.196, P<0.001; χ(2)=72.310, P<0.001). There also appeared significant differences in the frequencies of speA, speH, speI and speJ between emm1 and emm12 strains (χ(2)=146.154, P<0.001; χ(2)=52.31, P<0.001; χ(2)=58.43, P<0.001; χ(2)=144.70, P<0.001). Conclusions: Obvious changes were noticed among SAg genes including speC, speG, speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. SAg genes including speA, speH, speI and speJ appeared to be associated with the emm 1 and emm 12 strains. More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles, during the epidemic period.

FOXA1 inhibits prostate cancer neuroendocrine differentiation

Neuroendocrine prostate cancer (NEPC) has increasingly become a clinical challenge. The mechanisms by which neuroendocrine (NE) cells arises from prostate adenocarcinoma cells are poorly understood. FOXA1 is a transcription factor of the forkhead family that is required for prostate epithelial differentiation. In this study, we demonstrated that FOXA1 loss drives NE differentiation, demarcated by phenotypical changes and NEPC marker expressions. Mechanistically, this is mediated by FOXA1 binding to the promoter of interleukin 8 (IL-8), a chemokine previously shown elevated in NEPC, to directly inhibit its expression. Further, IL-8 upregulation activates the MAPK/ERK pathway, leading to ERK phosphorylation and enolase 2 (ENO2) expression. IL-8 knockdown or ERK inhibition, on the other hand, abolished FOXA1 loss-induced NE differentiation. Analysis of xenograft mouse models confirmed FOXA1 loss in NEPC tumors relative to its adenocarcinoma counterparts. Importantly, FOXA1 is downregulated in human NEPC tumors compared to primary and castration-resistant prostate cancers, and its expression is negatively correlated with that of ENO2. These findings indicate that FOXA1 transcriptionally suppresses IL-8, the expression of which would otherwise stimulate the MAPK/ERK pathway to promote NE differentiation of prostate cancer cells. Our data strongly suggest that FOXA1 loss may play a significant role in enabling prostate cancer progression to NEPC, whereas IL-8 and MAPK/ERK pathways may be promising targets for therapeutic intervention.

PKK deficiency in B cells prevents lupus development in Sle lupus mice

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies that can result in damage to multiple organs. It is well documented that B cells play a critical role in the development of the disease. We previously showed that protein kinase C associated kinase (PKK) is required for B1 cell development as well as for the survival of recirculating mature B cells and B-lymphoma cells. Here, we investigated the role of PKK in lupus development in a lupus mouse model. We demonstrate that the conditional deletion of PKK in B cells prevents lupus development in Sle1Sle3 mice. The loss of PKK in Sle mice resulted in the amelioration of multiple classical lupus-associated phenotypes and histologic features of lupus nephritis, including marked reduction in the levels of serum autoantibodies, proteinuria, spleen size, peritoneal B-1 cell population and the number of activated CD4 T cells. In addition, the abundance of autoreactive plasma cells normally seen in Sle lupus mice was also significantly decreased in the PKK-deficient Sle mice. Sle B cells deficient in PKK display defective proliferation responses to BCR and LPS stimulation. Consistently, B cell receptor-mediated NF-κB activation, which is required for the survival of activated B cells, was impaired in the PKK-deficient B cells. Taken together, our work uncovers a critical role of PKK in lupus development and suggests that targeting the PKK-mediated pathway may represent a promising therapeutic strategy for lupus treatment.

[The expression of MiR-148a in nasopharyngeal carcinoma and its effect on tumor cell biology functions in nasopharyngeal carcinoma]

Objective:Nasopharyngeal carcinoma(NPC) is a common malignant tumor, in recent years,most of studies have found that micro RNA played an important role in the development of NPC.This study was to explore the expression level of MiR-148a and its effect on the biological functions of NPC cells.Method:The expression of MiR-148a in NPC cell line CNE2 was detected by Real-time PCR method.MTT,clone formation assay and flow cytometry were applied to detect cell proliferation and apoptosis. We predicted that EGFR was the downstream target genes of MiR-148a through the analysis of bioinformatics software. Then the expression change of EGFR was measured by Real-time PCR and Western blot.Result:Comparing with normal nasopharyngeal epithelial tissue cells,MiR-148a expression level was significantly reduced in NPC cell line CNE2.MTT,clone formation assay and flow cytometry test show that overexpression of MiR-148a can inhibit cell proliferation and promote cell apoptosis.Real-time PCR and Western blot test show that MiR 148a can reduce the expression of EGFR.Conclusion:MiR-148a can affect the proliferation and apoptosis of NPC cell,and it is likely to be involved in the development and progression of NPC.

[The clinical application of balloon dilation Eustachian tuboplasty in patients with Eustachian tube dysfunction]

Objective:To evaluate the clinical application of balloon dilation Eustachian tuboplasty (BET) in patients with Eustachian tube dysfunction (ETD). Method:Twenty-five patients who were diagnosed as ETD and reserved BET surgery were retrospectively analyzed in this study. Result:After 1-year's follow-up, among 25 ETD patients, the total cure rate was 55.9% and the effective rate was 85.3%. The cure rate and effective rate was 52.9% and 76.5% in the delayed opening of the ET group; 58.8% and 94.1% in the unopened group, which was higher than the other one. Conclusion:BET surgery is safe and effective in the treatment of BET patients.

FOXA1 acts upstream of GATA2 and AR in hormonal regulation of gene expression

Hormonal regulation of gene expression by androgen receptor (AR) is tightly controlled by many transcriptional cofactors, including pioneer factors FOXA1 and GATA2, which, however, exhibit distinct expression patterns and functional roles in prostate cancer. Here, we examined how FOXA1, GATA2, and AR crosstalk and regulate hormone-dependent gene expression in prostate cancer cells. ChIP-seq analysis revealed that FOXA1 reprograms both AR and GATA2 cistrome by preferably recruiting them to FKHD-containing genomic sites. By contrast, GATA2 is unable to shift AR or FOXA1 to GATA motifs. Rather, GATA2 co-occupancy enhances AR and FOXA1 binding to nearby ARE and FKHD sites, respectively. Similarly, AR increases, but not re-programs, GATA2 and FOXA1 cistromes. Concordantly, GATA2 and AR strongly enhance the transcriptional program of each other, whereas FOXA1 regulates GATA2- and AR-mediated gene expression in a context-dependent manner due to its reprogramming effects. Taken together, our data delineated for the first time the distinct mechanisms by which GATA2 and FOXA1 regulate AR cistrome and suggest that FOXA1 acts upstream of GATA2 and AR in determining hormone-dependent gene expression in prostate cancer.

Genetic diversity and the conservation priority of Glycine soja populations from Northern China

Knowledge of the spatial patterns of genetic variation in wild populations has significant implications for in situ conservation and the determination of conservation order. To study the levels of genetic diversity, spatial genetic structures, and genetic distances in Glycine soja, 11 natural populations in northern China were analyzed by estimating genetic coefficients using inter-simple sequence repeat (ISSR) fingerprints via mixed sampling strategies. Sixteen ISSR primers generated 98 reproducible polymorphic amplification banding patterns of 172 scored, accounting for 56.98% of the polymorphisms among the populations. The dendrogram based on Nei's genetic distance showed that distinct genetic differentiation occurred in G. soja. The Unweighted Pair-Group Method with Arithmetic Mean cluster analysis indicated two broad groups, and one contained all of the populations except three from Chengde, which formed the smaller second group. The spatial genetic structure evident in the wild soybean populations may be attributed to restricted seed dispersal and the dominant breeding system of this species. The detection of genetic structures in wild soybean populations could be a significant index for the effective conservation of many wild populations, and it could be exploited by soybean breeding programs to increase production.

The roles of dihydrogen bonds in amine borane chemistry

A dihydrogen bond (DHB) is an electrostatic interaction between a protonic hydrogen and a hydridic hydrogen. Over the past two decades, researchers have made significant progress in the identification and characterization of DHBs and their properties. In comparison with conventional hydrogen bonds (HBs), which have been widely used in catalysis, molecular recognition, crystal engineering, and supramolecular synthesis, chemists have only applied DHBs in very limited ways. Considering that DHBs and conventional HBs have comparable strength, DHBs could be more widely applied in chemistry. Over the past several years, we have explored the impact of DHBs on amine borane chemistry and the syntheses and characterization of amine boranes and ammoniated metal borohydrides for hydrogen storage. Through systematic computational and experimental investigations, we found that DHBs play a dominant role in dictating the reaction pathways (and thus different products) of amine boranes where oppositely charged hydrogens coexist for DHB formation. Through careful experiments, we observed, for the first time, a long-postulated reaction intermediate, ammonia diborane (AaDB), whose behavior is essential to mechanistic understanding of the formation of the diammoniate of diborane (DADB) in the reaction of ammonia (NH3) with tetrahydrofuran borane (THF·BH3). The formation of DADB has puzzled the boron chemistry community for decades. Mechanistic insight enabled us to develop facile syntheses of aminodiborane (ADB), ammonia borane (AB), DADB, and an inorganic butane analog NH3BH2NH2BH3 (DDAB). Our examples, together with those in the literature, reinforce the fact that DHB formation and subsequent molecular hydrogen elimination are a viable approach for creating new covalent bonds and synthesizing new materials. We also review the strong effects of DHBs on the stability of conformers and the hydrogen desorption temperatures of boron-nitrogen compounds. We hope that this Account will encourage further applications of DHBs in molecular recognition, host-guest chemistry, crystal engineering, supramolecular chemistry, molecular self-assembly, chemical kinetics, and the syntheses of new advanced materials.

Invited article: micron resolution spatially resolved measurement of heat capacity using dual-frequency time-domain thermoreflectance

A pump-probe photothermal technique - dual-frequency time-domain thermoreflectance - was developed for measuring heat capacity with a spatial resolution on the order of 10 μm. The method was validated by measuring several common materials with known heat capacity. Rapid measurement of composition-phase-property relationships was demonstrated on Ti-TiSi2 and Ni-Zr diffusion couples; experimental values of heat capacity of the intermetallic compounds in these diffusion couples were compared with literature values and CALPHAD (CALculation of PHAse Diagram) calculations. The combination of this method and diffusion multiples provides an efficient way to generate thermodynamic data for CALPHAD modeling and database construction. The limitation of this method in measuring low thermal diffusivity materials is also discussed.

Dynamic surface acoustic response to a thermal expansion source on an anisotropic half space

The surface displacement response to a distributed thermal expansion source is solved using the reciprocity principle. By convolving the strain Green's function with the thermal stress field created by an ultrafast laser illumination, the complete surface displacement on an anisotropic half space induced by laser absorption is calculated in the time domain. This solution applies to the near field surface displacement due to pulse laser absorption. The solution is validated by performing ultrafast laser pump-probe measurements and showing very good agreement between the measured time-dependent probe beam deflection and the computed surface displacement.

Enhanced stability of horseradish peroxidase encapsulated in acetalated dextran microparticles stored outside cold chain conditions

Micro- and nanoparticles have been shown to improve the efficacy of safer protein-based (subunit) vaccines. Here, we evaluate a method of improving the vaccine stability outside cold chain conditions by encapsulation of a model enzyme, horseradish peroxidase (HRP), in an acid-sensitive, tunable biodegradable polymer, acetalated dextran (Ac-DEX). Vaccines that are stable outside the cold chain would be desirable for use in developing nations. Ac-DEX particles encapsulating HRP were prepared using two different methods, probe sonication and homogenization. These particles were stored under different storage conditions (-20 °C, 4 °C, 25 °C or 45 °C) for a period of 3 months. On different days, the particles were characterized for various physical and chemical measurements. At all conditions, Ac-DEX particles remained spherical in nature, as compared to PLGA particles that fused together starting at day 3 at 45 °C. Furthermore, our results indicated that encapsulation of HRP in Ac-DEX reduces its storage temperature dependence and enhances its stability outside cold chain conditions. Homogenized particles performed better than probe sonicated particles and retained 70% of the enzyme's initial activity as compared to free HRP that retained only 40% of the initial activity after 3 months of storage at 25 °C or 45 °C. Additionally, HRP activity was more stable when encapsulated in Ac-DEX, and the variance in enzyme activity between the different storage temperatures was not observed for either particle preparation. This suggests that storage at a constant temperature is not required with vaccines encapsulated in Ac-DEX particles. Overall, our results suggest that an Ac-DEX based micro-/nanoparticles system has wide applications as vaccines and drug delivery carriers, including those in developing nations.

Spontaneous cerebrospinal fluid leaks in congenital and acquired temporal bone defects-a long-term follow-up

Twelve patients presenting with tegmen defects and requiring surgical repair were retrospectively reviewed from 1982 to 1993. One half of the patients presented with a cerebrospinal fluid leak at some time in the course of their illness. Nine cases were considered to be acquired, secondary to previous mastoid surgery or trauma. All 9 had encephalocoeles. Three spontaneous leaks were considered congenital; 2 of these patients had encephalocoeles. This report represents a long-term follow-up of these cases, with an average follow-up of 7,6 years. Computed tomography and magnetic resonance imaging technology, as well as contrast studies, have tremendously aided in diagnosis and planning of surgical repair. Nine repairs were done through a dual transmastoid and middle fossa approach, with the other 3 done via a transmastoid approach only. We favored temporalis muscle flaps and temporalis fascia over synthetic materials for defect repairs. The long-term results and complications are discussed.

Ammonium octahydrotriborate (NH4B3H8): new synthesis, structure, and hydrolytic hydrogen release

A metathesis reaction between unsolvated NaB(3)H(8) and NH(4)Cl provides a simple and high-yield synthesis of NH(4)B(3)H(8). Structure determination through X-ray single crystal diffraction analysis reveals weak N-H(δ+)---H(δ-)-B interaction in NH(4)B(3)H(8) and strong N-H(δ+)---H(δ-)-B interaction in NH(4)B(3)H(8)·18-crown-6·THF adduct. Pyrolysis of NH(4)B(3)H(8) leads to the formation of hydrogen gas with appreciable amounts of other volatile boranes below 160 °C. Hydrolysis experiments show that upon addition of catalysts, NH(4)B(3)H(8) releases up to 7.5 materials wt % hydrogen.

Redetermination of di-μ-hydrido-hexa-hydridotetra-kis(tetra-hydro-furan)dialuminium(III)magnesium(II)

The structure of the title compound, [Mg(AlH₄)₂(C₄H₈O)₄], has been redetermined at 150 K. The Mg^II ion is hexa­coordinated to four tetra­hydro­furan (THF) ligands, and two AlH₄⁻ anions through bridging H atoms. The Al—H distances are more precise compared to those previously determined [Nöth et al. (1995 ▶). Chem. Ber. 128, 999–1006; Fichtner & Fuhr (2002 ▶). J. Alloys Compd, 345, 386–396]. The mol­ecule has twofold rotation symmetry.

Preliminary experience with indications for liver transplantation for hepatolithiasis

OBJECTIVE

The aim of this study was to explore the indications for liver transplantation among patients with hepatolithiasis.

PATIENTS AND METHODS

Data from 1,431 consecutive patients who underwent surgical treatment from January 2000 to December 2006 were retrospectively collected for analysis. Surgical procedures included T-tube insertion combined with intraoperative cholangioscopic removal of intrahepatic stones, hepatectomy, cholangiojejunostomy, and liver transplantation.

RESULTS

Nine hundred sixty-one patients who had a stone located in the left or right intrahepatic duct underwent hepatectomy or T-tube insertion combined with intraoperative cholangioscopic removal of intrahepatic stones. The rate of residual stones was 7.5%. Four hundred seventy patients who had a stone located in the bilateral intrahepatic ducts underwent surgical procedures other than liver transplantation; the rate of residual stones was 21.7%. Only 15 patients with hepatolithiasis underwent liver transplantation; they all survived. According to the degree of biliary cirrhosis, recipients were divided into 2 groups: a group with biliary decompensated cirrhosis (n = 7), or group with compensated cirrhosis or no cirrhosis (n = 8). There were significant differences in operative times, transfusion volumes, and blood losses between the 2 groups (P < .05). In the first group, 6 of 7 patients experienced surgical complications, and in the second, 8 recipients recovered smoothly with no complications. Health status, disability, and psychological wellness of all recipients (n = 15) were significantly improved at 1 year after transplantation compared with pretransplantation (P < .05).

CONCLUSIONS

Liver transplantation is a possible method to address hepatolithiasis and secondary decompensated biliary cirrhosis or difficult to remove, diffusely distributed intrahepatic duct stones unavailable by hepatectomy, cholangiojejunostomy, and choledochoscopy.

Estimation of standard liver volume for liver transplantation in the Chinese population

INTRODUCTION

The accurate assessment of standard liver volume (SLV) is necessary for the safety of both the donor and the recipient in living donor liver transplantation. However, the accuracy of SLV formulas relates to cohorts or races. This study examined the accuracy of a simple linear formula versus previous formulas of SLV for Chinese adults.

METHODS

Among 112 patients with normal liver, we created a new formula for SLV with stepwise regression analysis using the following variables: age, gender, body weight, body height, body mass index, and body surface area. The agreement between the actual liver volume (LV) and calculated LV using various formulas was prospectively evaluated among 63 living donors by paired-sample student's t-test and Lin's concordance correlation coefficient.

RESULTS

A new formula was developed SLV (mL) = 949.7 x BSA (m(2)) - 48.3 x age - 247.4 where age was counted as 1 for those <40, 2 if 41-60, and 3 if >60 years old. The calculated LV using our formula showed no significant difference from the actual LV using the paired-samples student's t-test (P = .653). Lin's concordance correlation coefficient showed substantial agreement between estimated LV using our formula and actual LV. Furthermore, this study also observed an almost perfect agreement between our formula and the Yoshizumi et al formula.

CONCLUSION

Our formula, which accurately estimated LV among Chinese adults, may be applicable to adults of other ethnicitis.

Phase transition between nanostructures of titanate and titanium dioxides via simple wet-chemical reactions

Titanate nanofibers of various sizes and layered structure were prepared from inorganic titanium compounds by hydrothermal reactions. These fibers are different from "refractory" mineral substances because of their dimension, morphology, and significant large ratio of surface to volume, and, surprisingly, they are highly reactive. We found, for the first time, that phase transitions from the titanate nanostructures to TiO(2) polymorphs take place readily in simple wet-chemical processes at temperatures close to ambient temperature. In acidic aqueous dispersions, the fibers transform to anatase and rutile nanoparticles, respectively, but via different mechanisms. The titanate fibers prepared at lower hydrothermal temperatures transform to TiO(2) polymorphs at correspondingly lower temperatures because they are thinner, possess a larger surface area and more defects, and possess a less rigid crystal structure, resulting in lower stability. The transformations are reversible: in this case, the obtained TiO(2) nanocrystals reacted with concentrate NaOH solution, yielding hollow titanate nanotubes. Consequently, there are reversible transformation pathways for transitions between the titanates and the titanium dioxide polymorphs, via wet-chemical reactions at moderate temperatures. The significance of these findings arises because such transitions can be engineered to produce numerous delicate nanostructures under moderate conditions. To demonstrate the commercial application potential of these processes, we also report titanate and TiO(2) nanostructures synthesized directly from rutile minerals and industrial-grade rutiles by a new scheme of hydrometallurgical reactions.

Phase transition between nanostructures of titanate and titanium dioxides via simple wet-chemical reactions

Titanate nanofibers of various sizes and layered structure were prepared from inorganic titanium compounds by hydrothermal reactions. These fibers are different from "refractory" mineral substances because of their dimension, morphology, and significant large ratio of surface to volume, and, surprisingly, they are highly reactive. We found, for the first time, that phase transitions from the titanate nanostructures to TiO(2) polymorphs take place readily in simple wet-chemical processes at temperatures close to ambient temperature. In acidic aqueous dispersions, the fibers transform to anatase and rutile nanoparticles, respectively, but via different mechanisms. The titanate fibers prepared at lower hydrothermal temperatures transform to TiO(2) polymorphs at correspondingly lower temperatures because they are thinner, possess a larger surface area and more defects, and possess a less rigid crystal structure, resulting in lower stability. The transformations are reversible: in this case, the obtained TiO(2) nanocrystals reacted with concentrate NaOH solution, yielding hollow titanate nanotubes. Consequently, there are reversible transformation pathways for transitions between the titanates and the titanium dioxide polymorphs, via wet-chemical reactions at moderate temperatures. The significance of these findings arises because such transitions can be engineered to produce numerous delicate nanostructures under moderate conditions. To demonstrate the commercial application potential of these processes, we also report titanate and TiO(2) nanostructures synthesized directly from rutile minerals and industrial-grade rutiles by a new scheme of hydrometallurgical reactions.

Thermal conductivity imaging at micrometre-scale resolution for combinatorial studies of materials

Combinatorial methods offer an efficient approach for the development of new materials. Methods for generating combinatorial samples of materials, and methods for characterizing local composition and structure by electron microprobe analysis and electron-backscatter diffraction are relatively well developed. But a key component for combinatorial studies of materials is high-spatial-resolution measurements of the property of interest, for example, the magnetic, optical, electrical, mechanical or thermal properties of each phase, composition or processing condition. Advances in the experimental methods used for mapping these properties will have a significant impact on materials science and engineering. Here we show how time-domain thermoreflectance can be used to image the thermal conductivity of the cross-section of a Nb-Ti-Cr-Si diffusion multiple, and thereby demonstrate rapid and quantitative measurements of thermal transport properties for combinatorial studies of materials. The lateral spatial resolution of the technique is 3.4 microm, and the time required to measure a 100 x 100 pixel image is approximately 1 h. The thermal conductivity of TiCr(2) decreases by a factor of two in crossing from the near-stoichiometric side of the phase to the Ti-rich side; and the conductivity of (Ti,Nb)(3)Si shows a strong dependence on crystalline orientation.

[Study on chemical constituents of the essential oil from Zanthoxylum Bungeanum Maxim by gas chromatography-mass spectrometry]

The essential oil in Zanthoxylum Bungeanum Maxim was extracted by steam distillation and the distilled liquid was collected by passing through chloroform. The aqueous phase was extracted with chloroform sufficiently. The chloroform solution containing the constituents of essential oils was analyzed by gas chromatography-mass spectrometry(GC-MS). Seventeen peaks were separated by gas chromatography, and 16 of them were identified by MS with "Nist98.L" Mass Spectral Data Registry. The structures of the constituents were further verified by manual analysis. The identified constituents accounted for 97% of the peak areas of the essential oils on total ion chromatogram. The major chemical constituents of them are C9, C10 alcohols and alkenes.

Cladonia furcata polysaccharide induced apoptosis in human leukemia K562 cells

AIM

To study whether Cladonia furcata polysaccharide (CFP-1) might induce apoptosis in human leukemia K562 cells.

METHODS

Inhibition of proliferation was measured by MTT assay. Morphological assessment of apoptosis was performed with fluorescence microscope and electron microscope. DNA fragmentation was visualized by agarose gel electrophoresis. The amount of apoptosis cells was measured by flow cytometry.

RESULTS

CFP-1 (50 - 800 mg/L) inhibited K562 cell proliferation in a concentration-dependent manner. After incubation of K562 cells with CFP-1 300 mg/L for 5 d, morphological changes of typical apoptosis were observed and agarose gel electrophoresis of DNA revealed "ladder" pattern.

CONCLUSION

CFP-1 induced apoptosis in human leukemia K562 cells.

[Study on reversed-phase high performance liquid chromatography separation condition and determination method of organic acids]

The pH values of the mobile phase which affect the chromatographic behavior of organic acids in RP-HPLC have been studied. It was considered that the problem of organic acids on an RP-HPLC column was dissociation. The equation for finding the optimum pH of mobile phase was pHlimit of colunm < or = pH < or = pKa -2. In addition the effects of contents of methanol and acetonitrile in mobile phase were studied. By using the formula the mobile phases used for the analysis of organic monobasic acids--formic, acetic, propionic and butyric acid and of organic dibasic acids--propane diacid, butane diacid, pentane diacid and hexane diacid were proposed. For the analysis of the monobasic acids, the wavelength of UV-detector was set at 210 nm and the mobile phase was a mixture of phosphate buffer solution(15 mmol/L, pH 2.1)-methanol(85:15, V/V) and at a rate of 1.5 mL/min and the column was Diamond C18, 150 mm x 4.6 mm i.d.. The average coefficient of correlation was 0.9997 and RSD was less than 0.90%. The mobile phase for organic dibasic acids was a mixture of phosphate buffer solution (20 mmol/L, pH 2.1)-methanol(75:25, V/V). The other conditions were the same as for organic monobasic acids. The average coefficient of correlation was 0.9998 and RSD was less than 0.70%.

[Determination of bentazon and 2,4-D butyl in mixture formulation by HPLC]

Bentazon and 2,4-D butyl(the active ingredients of Cao Di) were determined by reversed phase HPLC aimultancously using methanol/acetonitrile/citrate buffer(pH 3.1) as a mobile phase on Shim-pack clc-CN column. Results showed that the linear correlation and recovery of 2,4-D butyl were 1.000 and (100.2 +/- 0.8)% respectively, and those of bentazon were 1.000 and (98.6 +/- 0.9)% respectively. The coefficients of variation for bentazon and 2,4-D butyl were all was 0.37%.

Olfactory secretion and sodium, potassium-adenosine triphosphatase: regulation by corticosteroids

OBJECTIVES

To investigate the cellular distribution and relative intensity of the immunoreactivity associated with the expression of sodium, potassium-adenosine triphosphatase (Na, K-ATPase) in cells of the olfactory mucosa. Second, changes in the activity of this enzyme in the olfactory mucosa are correlated with changes in the circulating corticosteroid aldosterone.

METHODS

Combination of immunohistochemical and biochemical techniques were employed to examine the olfactory Na, K-ATPase.

RESULTS

Within the olfactory epithelium, the Na, K-ATPase immunoreactivity was greatest at the supranuclear region of sustentacular cells and/or dendrites of olfactory receptor neurons (ORNs). Cell bodies of ORNs demonstrated moderate immunoreactivity, whereas the duct cells of Bowman's gland exhibited moderate to intense immunoreactivity. Acinar cells of the Bowman's gland were the most intensely stained components of the lamina propria, exhibiting strong immunoreactivity at the basolateral plasma membrane domains of the acinar cells and less within the cytoplasm. Binding of ouabain, a specific inhibitor of Na, K-ATPase, was significantly elevated for aldosterone-injected versus sham-injected controls.

CONCLUSION

These results suggest that olfactory Na, K-ATPase is regulated by the systemic corticosteroid aldosterone. The results are consistent with the hypothesis that corticosteroids regulate olfactory secretion.

Position-dependent variegation of a CD4 minigene with targeted expression to mature CD4+ T cells

The CD4 gene follows a complex and highly regulated pattern of expression throughout T cell development. This expression is governed by different regulatory elements that have been partly identified, including a promoter, a proximal enhancer, and a silencer. Here we show that a CD4 minigene comprising a combination of these elements is specifically expressed in mature CD4+ T cells of transgenic mice, but not in CD4+CD8+ double positive thymocytes. The proportion of transgene-expressing CD4+ T cells was constant within a given transgenic line, but varied greatly from one line to another. We demonstrate that this pattern of expression is due to integration of the transgene within or in the vicinity of centromeric heterochromatin. This position-effect variegation demonstrated with a short CD4 transgene has not been observed with larger ones containing additional regulatory sequences, suggesting that the CD4 gene contains a locus control region. Such position-dependent effects must be taken into consideration when developing transgenic models or gene transfer vectors because they can result in the absence of transgene expression in a subpopulation of target cells. Finally, the combination of the CD4 gene silencer, proximal enhancer, and promoter provides an interesting tool to selectively express genes of interest in mature CD4+ T cells of transgenic mice and for the development of gene therapy vectors.

Position-dependent variegation of a CD4 minigene with targeted expression to mature CD4+ T cells

The CD4 gene follows a complex and highly regulated pattern of expression throughout T cell development. This expression is governed by different regulatory elements that have been partly identified, including a promoter, a proximal enhancer, and a silencer. Here we show that a CD4 minigene comprising a combination of these elements is specifically expressed in mature CD4+ T cells of transgenic mice, but not in CD4+CD8+ double positive thymocytes. The proportion of transgene-expressing CD4+ T cells was constant within a given transgenic line, but varied greatly from one line to another. We demonstrate that this pattern of expression is due to integration of the transgene within or in the vicinity of centromeric heterochromatin. This position-effect variegation demonstrated with a short CD4 transgene has not been observed with larger ones containing additional regulatory sequences, suggesting that the CD4 gene contains a locus control region. Such position-dependent effects must be taken into consideration when developing transgenic models or gene transfer vectors because they can result in the absence of transgene expression in a subpopulation of target cells. Finally, the combination of the CD4 gene silencer, proximal enhancer, and promoter provides an interesting tool to selectively express genes of interest in mature CD4+ T cells of transgenic mice and for the development of gene therapy vectors.