Development of DRAGON electron cyclotron resonance ion source at Institute of Modern Physics

A new room temperature electron cyclotron resonance (ECR) ion source, DRAGON, is under construction at IMP. DRAGON is designed to operate at microwaves of frequencies of 14.5-18 GHz. Its axial solenoid coils are cooled with evaporative medium to provide an axial magnetic mirror field of 2.5 T at the injection and 1.4 T at the extraction, respectively. In comparison to other conventional room temperature ECR ion sources, DRAGON has so far the largest bore plasma chamber of inner diameter of 126 mm with maximum radial fields of 1.4-1.5 T produced by a non-Halbach permanent sextupole magnet.

Status of the laser ion source at IMP

A laser (Nd:YAG laser, 3 J, 1064 nm, 8-10 ns) ion source has been built and under development at IMP to provide pulsed high-charge-state heavy ion beams to a radio frequency quadrupole (RFQ) for upgrading the IMP accelerators with a new low-energy beam injector. The laser ion source currently operates in a direct plasma injection scheme to inject the high charge state ions produced from a solid target into the RFQ. The maximum power density on the target was about 8.4 × 10(12) W∕cm(2). The preliminary experimental results will be presented and discussed in this paper.

A 2.45 GHz electron cyclotron resonance proton ion source and a dual-lens low energy beam transport

The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.

Study of ion beam transport from the SECRAL electron cyclotron resonance ion source at the Institute of Modern Physics

Ion beam transport from the Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) electron cyclotron resonance ion source was studied at the Institute of Modern Physics during 2010. Particle-in-cell simulations and experimental results have shown that both space charge and magnetic aberrations lead to a larger beam envelope and emittance growth. In the existing SECRAL extraction beam line, it has been shown that raising the solenoid lens magnetic field reduces aberrations in the subsequent dipole and results in lower emittance. Detailed beam emittance measurements are presented in this paper.

Nonpenetrating clips successfully replacing sutures in base of skull surgery

Reconstructive challenges engendered by skull base surgery are critical determinants of outcome. A novel nonpenetrating, arcuate-legged clip has proven to be both technically and biologically effective for management of these difficult closures. Clips have facilitated reconstructions associated with the surgical management of eight skull base cases: leiomyosarcoma of the orbit, middle fossa, ptyergopalatine fossa, two meningiomas (petrotentorial, cavernous sinus), vagus nerve paraganglioma, complex traumatic orbital dural tear, and one basilar and two vertebral artery aneurysms.

Measurement of the parity-violating longitudinal single-spin asymmetry for W± boson production in polarized proton-proton collisions at sqrt[s] = 500 GeV

We report the first measurement of the parity-violating single-spin asymmetries for midrapidity decay positrons and electrons from W+ and W- boson production in longitudinally polarized proton-proton collisions at sqrt[s] = 500 GeV by the STAR experiment at RHIC. The measured asymmetries, A(L)(W+) = -0.27 ± 0.10(stat.) ± 0.02(syst.) ± 0.03(norm.) and A(L)(W-) = 0.14 ± 0.19(stat.) ± 0.02(syst.) ± 0.01(norm.), are consistent with theory predictions, which are large and of opposite sign. These predictions are based on polarized quark and antiquark distribution functions constrained by polarized deep-inelastic scattering measurements.

Use of EBSD to study electropulsing induced reverse phase transformations in a Zn-Al alloy (ZA22)

Multi-phase identification and phase transformations in electropulsing treated Zn-Al based alloy wire specimens were studied using electron back-scattered diffraction, back-scattered scanning electron microscopy and X-ray diffraction techniques. By using electron back-scattered diffraction, two phases: η'(S) and η'(T) with a small difference of about 1% in lattice parameters (c(0)/a(0) ) were identified, based on the determined lattice parameters of the phases, and the reverse eutectoid phase transformations: η'(T) +ɛ'(T) +α'(T) →η'(S) and ɛ+α→T'+η were successfully detected. Electron back-scattered diffraction appeared to be an effective technique for studying complex electropulsing induced phase transformations.

Characterization of skin friction coefficient, and relationship to stratum corneum hydration in a normal Chinese population

BACKGROUND AND OBJECTIVES

Studies have demonstrated that some cutaneous biophysical properties vary with age, gender and body sites. However, the characteristics of the skin friction coefficient in different genders and age groups have not yet been well established. In the present study, we assess the skin friction coefficient in a larger Chinese population.

METHODS

A total of 633 subjects (300 males and 333 females) aged 0.15-79 years were enrolled. A Frictiometer FR 770 and Corneometer CM 825 (C&K MPA 5) were used to measure the skin friction coefficient and stratum corneum hydration, respectively, on the dorsal surface of the hand, the forehead and the canthus.

RESULTS

In the females, the maximum skin friction coefficients on both the canthus and the dorsal hand skin were observed around the age of 40 years. In the males, the skin friction coefficient on the dorsal hand skin gradually increased from 0 to 40 years of age, and changed little afterward. Skin friction coefficients on some body sites were higher in females than in age-matched males in some age groups. On the canthus and the dorsal hand skin of females, a positive correlation was found between skin friction coefficient and stratum corneum hydration (p < 0.001 and p < 0.0001, respectively). In contrast, in males, the skin friction coefficient was positively correlated with stratum corneum hydration on the forehead and the dorsal hand skin (p < 0.05 and p < 0.0001, respectively).

CONCLUSION

The skin friction coefficient varies with age, gender and body site, and positively correlates with stratum corneum hydration on some body sites.

Measurement of the bottom quark contribution to nonphotonic electron production in p + p collisions at √s=200 GeV

The contribution of B meson decays to nonphotonic electrons, which are mainly produced by the semileptonic decays of heavy-flavor mesons, in p + p collisions at √s=200  GeV has been measured using azimuthal correlations between nonphotonic electrons and hadrons. The extracted B decay contribution is approximately 50% at a transverse momentum of pT≥5  GeV/c. These measurements constrain the nuclear modification factor for electrons from B and D meson decays. The result indicates that B meson production in heavy ion collisions is also suppressed at high pT.

Higher moments of net proton multiplicity distributions at RHIC

We report the first measurements of the kurtosis (κ), skewness (S), and variance (σ2) of net-proton multiplicity (Np-Np) distributions at midrapidity for Au+Au collisions at square root of s(NN)=19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (μB) between 200 and 20 MeV. Our measurements of the products κσ2 and Sσ, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the square root of s(NN) dependence of κσ2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for μB below 200 MeV.

[Two outbreaks of eosinophilic meningitis in Yunann (China) clinical, epidemiological and therapeutical issues]

Eosinophilic meningitis is an uncommon clinical entity, which is mostly caused by Angiostrongylus cantonensis, a nematode which parasitizes rat's lungs. Humans represent a dead-end in the parasite's lifecycle and become infected by ingesting snails, slugs or transport hosts. Due to uncontrolled proliferation and circulation of snails and rats, human angiostrongyliasis has emerged in new foci in continental China. The treatment, which relies upon a combination of albendazole and corticosteroids, is still a matter of debate. In order to assess the epidemiological features of two outbreaks which occurred in Kunming, capital of the Yunnan province, 2003 and 2005, along with the clinical and treatment issues, a retro-prospective study was carried out among thirty-four clinical cases of eosinophilic meningitis. Furthermore, a parasitological survey was carried out on randomized samples of snails sold in the markets of the city On admission, all cases were found to have acute headaches and an eosinophilic pleocytosis rate > 5% in the cerebro spinal fluid (CSF). All patients reported the consumption of raw snails Pomacea canaliculata, 14 days on average before the onset of headaches (range 1-30 days). Hyperesthesia due to radiculitis was observed in 68% of the cases and the meningitis syndrome was present in 41%. The average value of blood eosinophil count in CSF and in peripheral blood was 38% and 900/ml, respectively. Two treatment schedules were used (without randomization): one with progressive doses over 4 weeks; the other with immediate high doses for 10 days with 3 sessions separated by 14-day intervals. The results were compared by the Kaplan Meier log rank test. All the cases had a favorable evolution. The analysis suggested better effectiveness and tolerance of the albendazole - dexamethasone combination used at the highest dosage, namely 20mglkg daily and 10mg daily respectively. Eosinophilic meningitis appeared to be recently emerging or re-emerging in Kunming. Deep-rooted culinary habits of eating raw food, and large amount of snails sold on local markets (about one ton per day) provide ideal conditions for the outbreak, or occurrence of this disease. According to the resdjlts of this study Chinese local authorities should be urged to improve information to the population about the risks of eating raw snails, in order to strengthen the control of both rat and snail populations and reinforce the supervision of local food markets.

Effect of early insulin therapy on nuclear factor kappaB and cytokine gene expressions in the liver and skeletal muscle of high-fat diet, streptozotocin-treated diabetic rats

To clarify the effect of early insulin therapy on nuclear factor kappaB (NFkappaB) pathway and inflammatory cytokine responses in the liver and skeletal muscle in type 2 diabetes. High-fat diet and low dose streptozotocin (STZ) induced diabetic rats were given NPH insulin or gliclazide for 3 weeks initiated at the 3rd day after STZ injection as early treatment and NPH for 3 weeks at 1 month as late treatment. Intraperitoneal glucose tolerance test (IPGTT) was performed at 3rd day after the end of treatment. Early interventions caused a decrease in glucose-insulin index in IPGTT, promoted glucose transporter 4 (Glut4) gene and protein expressions in muscle and reduced phosphoenolpyruvate carboxykinase (PEPCK) protein levels in the liver. There was an increase in inhibitor kappaB (IkappaBalpha) protein and a decrease in NFkappaB p65 DNA binding activity. A decreased level in mRNAs encoding tumor necrosis factor (TNF)alpha in the liver and muscle and interleukin (IL)-1beta in the liver were observed. Our results suggested that early insulin treatment inhibits NFkappaB activity and inflammatory cytokine responses in the liver and skeletal muscle that were involved in the amelioration of insulin resistance in type 2 diabetic rats.

Extreme ultraviolet narrow band emission from electron cyclotron resonance plasmas

Extreme ultraviolet lithography (EUVL) is considered as the most promising solution at and below dynamic random access memory 32 nm half pitch among the next generation lithography, and EUV light sources with high output power and sufficient lifetime are crucial for the realization of EUVL. However, there is no EUV light source completely meeting the requirements for the commercial application in lithography yet. Therefore, ECR plasma is proposed as a novel concept EUV light source. In order to investigate the feasibility of ECR plasma as a EUV light source, the narrow band EUV power around 13.5 nm emitted by two highly charged ECR ion sources -- LECR2M and SECRAL -- was measured with a calibrated EUV power measurement tool. Since the emission lines around 13.5 nm can be attributed to the 4d-5p transitions of Xe XI or the 4d-4f unresolved transition array of Sn VIII-XIII, xenon plasma was investigated. The dependence of the EUV throughput and the corresponding conversion efficiency on the parameters of the ion source, such as the rf power and the magnetic confinement configurations, were preliminarily studied.

Experimental study of hot electrons in LECR2M plasma

In order to investigate the hot electron component in electron cyclotron resonance (ECR) plasmas, the volume bremsstrahlung spectra in the x-ray photon energy range were measured with a high-purity germanium detector on Lanzhou ECR Ion Source No. 2 Modified (LECR2M). A collimation system similar to Bernhardi's was used to focus at the central part of the plasma. The ion source was operated under various source conditions with argon; sometimes oxygen was added to enhance high charge state ion beam intensities. The spectral temperature of hot electrons T(spe) was derived from the measured bremsstrahlung spectra. The evolution of the deduced temperature of hot electrons T(spe) with the ion source parameters, such as the rf frequency, power, and the magnetic confinement configuration, was investigated.

Short Communication: Changes in Micromineral, Magnesium, Cytokine, and Cortisol Concentrations in Blood of Dairy Goats Following Intramammary Inoculation with Staphylococcus aureus

The aim of this study was to investigate mineral metabolism and immune response in dairy goats following intramammary inoculation with varying doses of Staphylococcus aureus. Blood samples were collected at 0, 2, 4, 8, 12, 24, 48, and 72 h after intramammary inoculation. Lowered plasma Fe concentrations were observed from 12 to 24 h postinoculation in groups SAA (Staph. aureus at 10(4) cfu, n = 5) and SAB (Staph. aureus at 10(8) cfu, n = 5). Plasma Cu concentrations increased in group SAB 2 h after inoculation and maintained greater concentrations until the end of the experiment compared with the control group (phosphate-buffered saline, n = 5). Increased plasma Zn concentrations in group SAB were observed 48 h after inoculation, and the concentration was still greater 72 h after inoculation compared with the control group. Greater plasma Mg concentrations were detected in groups SAA and SAB compared with the control group at all timepoints after inoculation. Plasma Mg concentrations were generally greater in group SAA than in group SAB through 72 h (except at 2 h). Plasma tumor necrosis factor-alpha concentrations were unchanged following intramammary inoculation with Staph. aureus throughout the study. Plasma IL-6 concentrations in groups SAA and SAB increased gradually compared with the control group and peaked at 48 h after inoculation. In group SAB, serum cortisol concentrations started to increase from 8 h postinoculation and peaked at 12 h postinoculation. In conclusion, increasing the inoculum dose does not induce more rapid proinflammatory cytokine responses, whereas the data indicate that mineral metabolic alterations occur during the course of Staph. aureus mastitis in the goat.

Cerebral response to patient's own name in the vegetative and minimally conscious states

BACKGROUND

A challenge in the management of severely brain-damaged patients with altered states of consciousness is the differential diagnosis between the vegetative state (VS) and the minimally conscious state (MCS), especially for the gray zone separating these clinical entities.

OBJECTIVE

To evaluate the differences in brain activation in response to presentation of the patient's own name spoken by a familiar voice (SON-FV) in patients with VS and MCS.

METHODS

By using fMRI, we prospectively studied residual cerebral activation to SON-FV in seven patients with VS and four with MCS. Behavioral evaluation was performed by means of standardized testing up to 3 months post-fMRI.

RESULTS

Two patients with VS failed to show any significant cerebral activation. Three patients with VS showed SON-FV induced activation within the primary auditory cortex. Finally, two patients with VS and all four patients with MCS not only showed activation in primary auditory cortex but also in hierarchically higher order associative temporal areas. These two patients with VS showing the most widespread activation subsequently showed clinical improvement to MCS observed 3 months after their fMRI scan.

CONCLUSION

The cerebral responses to patient's own name spoken by a familiar voice as measured by fMRI might be a useful tool to preclinically distinguish minimally conscious state-like cognitive processing in some patients behaviorally classified as vegetative.

Use of EBSD to identify phases in interdendrite region of a cast Zn-Al-based alloy (ZA27)

Electron backscattered Kikuchi diffraction methodology was used to identify phases in the interdendrite region of an alloy ZA27. Two Zn-rich hexagonal close-packed structure phases eta and epsilon phases were distinguished using predetermined lattice parameters of the phases. In relation to studies of scanning electron microscopy and X-ray diffraction, electron backscattered diffraction results revealed that the Al-rich precipitates of the alpha phase were from decomposition of the eta'(T), and the four-phase transformation: alpha+epsilon--> T'+eta, had occurred in the epsilon phase after ageing at 150 degrees C for 8 h.

In vitro fermentation of various fiber and starch sources by pig fecal inocula1

Freeze-dried ileal effluent (1% wt/vol) from cannulated pigs fed rice-based diets with the inclusion of either animal protein (CON), animal protein plus potato starch (PS), animal protein plus sugar beet pulp (SBP), or animal protein plus wheat bran (WB) was incubated anaerobically at pH 6.0 in fermenters containing 5% (wt/vol) fecal slurry comprising mineral salts medium and 50 g/L of fresh feces from pigs fed the same diets as the cannulated pigs. Samples were collected from the fermenters at 0, 2, 4, 12, 24, and 48 h during in vitro fermentation for measuring nonstarch polysaccharides (NSP), starch, and short-chain fatty acids (SCFA). Results showed that the major SCFA produced were acetate, propionate, and butyrate. The inclusion of soluble dietary fiber (diet SBP) caused the highest concentrations of acetate, propionate, butyrate, and total SCFA, whereas the increase in the production of propionate resulting from the addition of insoluble dietary fiber (diet WB) only occurred at the initial stages during 48 h in vitro fermentation. At all sampling occasions (except for 4 h), the levels of butyrate were increased (P < 0.01) by resistant starch compared with fiber sources, showing that a higher level of butyrate can be achieved through microbial fermentation by potato starch. Lowered (P < 0.05) butyrate concentrations were observed with diet WB during in vitro fermentation. With the inclusion of fiber sources, the energy originating from SCFA was similar to that from NSP disappearance, whereas the values were lower (P < 0.05) from NSP disappearance than for SCFA generated without fiber sources supplemented. We conclude that more substrate is available in ileal effluent with the addition of soluble dietary fiber, and an increased level of butyrate could be achieved through microbial fermentation by resistant starch.

Distal rotational alignment of the Chinese femur and its relevance in total knee arthroplasty

The rotational alignments of the distal femur in southern Chinese subjects were investigated. Chinese femurs are significantly more externally rotated. This is new evidence to suggest a racial difference in the distal femoral geometry. During total knee arthroplasty, a common recommendation is to allow 4 degrees of external rotation. The clinical significance of our study is that this need to be modified to 6 degrees for Chinese women and 5 degrees for Chinese men. This racial difference can be incorporated into a new concept of "a mountain and a molehill." This concept is presented in this report.

Impact of nonpenetrating clips on intimal hyperplasia of vascular anastomoses

Non-penetrating, arcuate-legged titanium clips create an interrupted, non-penetrated, yet compliant vascular anastomoses that is associated with significantly reduced anastomotic neointimal hyperplasia. Recent experimental and clinical studies provide evidence that the non-suture alternative changes the biology of vessel-to-vessel and graft-to-vessel connections that reduces the stimulus for hyperplasia at a number of critical points in the response to injury schema. The compliant, "blood-tight" characteristics of clipped vascular reconstructions are associated with no endothelial injury or intraluminal foreign body, minimal platelet aggregation and laminal flow. Clinical applications including vascular access, femoropopliteal bypass, and closure of carotid endarterectomies are remarkable for the absence of restenosis and preserved anastomotic patency.

Sutureless vascular anastomosis: the VCS clip

Non-penetrating, arcuate-legged clips facilitate vascular reconstructions and significantly reduce the incidence of anastomotic neointimal hyperplasia. Though originally developed as a microvascular-approximating instrument, by far the largest application has been for hemodialysis vascular access. Long-term studies comparing suture to clip for access creation have demonstrated the clear technical and biological superiority of the clip for this procedure. This "sutureless" vascular anastomotic technique is more demanding than conventional suturing, requiring precise vessel preparation and supervised training.

An alternative system for cerebrovascular reconstructions: non-penetrating arcuate-legged clips

Non-penetrating, arcuate-legged titanium clips (VCS) have been utilized successfully over the past five years for a variety of cerebrovascular reconstructions. These applications, including both micro and macrovascular reconstructions, their clinical outcomes and technical considerations are described. Applications include patch angioplasty of cervical carotid endarterectomies, superficial temporal to middle cerebral artery 'bypass' procedures, Takayasu's arteritis and cavernous carotid reconstructions. The non-penetrating clip has proven to be a safe and reliable alternative to suture for these demanding reconstructions. Clips provide the advantages of improved anastomotic compliance, reduced operative time, and reduced incidence of post-operative anastomotic intimal hyperplasia and stenosis. Clip related pitfalls are discussed with recommendations regarding usage.

Altered extracellular matrix remodeling and angiogenesis in sponge granulomas of thrombospondin 2-null mice

The matricellular angiogenesis inhibitor, thrombospondin (TSP) 2, has been shown to be an important modulator of wound healing and the foreign body response. Specifically, TSP2-null mice display improved healing with minimal scarring and form well-vascularized foreign body capsules. In this study we performed subcutaneous implantation of sponges and investigated the resulting angiogenic and fibrogenic responses. Histological and immunohistochemical analysis of sponges, excised at 7, 14, and 21 days after implantation, revealed significant differences between TSP2-null and wild-type mice. Most notably, TSP2-null mice exhibited increased angiogenesis and fibrotic encapsulation of the sponge. However, invasion of dense tissue was compromised, even though its overall density was increased. Furthermore, histomorphometry and biochemical assays demonstrated a significant increase in the extracellular distribution of matrix metalloproteinase (MMP) 2, but no change in the levels of active transforming growth factor-beta(1). The alterations in neovascularization, dense tissue invasion, and MMP2 in TSP2-null mice coincided with the deposition of TSP2 in the extracellular matrix of wild-type animals. These observations support the proposed role of TSP2 as a modulator of angiogenesis and matrix remodeling during tissue repair. In addition, they provide in vivo evidence for a newly proposed function of TSP2 as a modulator of extracellular MMP2 levels.

Review Article: Polyethylene wear and osteolysis in total hip arthroplasty

Polyethylene wear has been accepted as a major cause of osteolysis in total hip arthroplasty. Submicron particles, which are secondary to abrasive wear, migrate into the effective joint space and stimulate a foreign-body response resulting in bone loss which is mainly mediated by macrophages. Diagnosis depends on serial radiographic evaluation and frequent follow-up. Polyethylene wear and osteolysis can be prevented by reducing the wear such as using a small femoral head, adaptive polyethylene thickness, suitable surgical techniques, non-polyethylene articulation, etc. The presence of cement or circumferential coatings may also retard the distal migration of particles. Medicines such as NSAIDs and bisphosphonate appear to inhibit the progress of osteolysis. As far as treatment, revision surgery is able to reconstruct the joint by replacing partial or total prosthesis and repair the defect by bone grafting according to intraoperative assessment.

Axial alignment of the lower extremity in Chinese adults

BACKGROUND

The restoration of normal axial alignment of the lower extremity is important to surgeons who perform reconstructive surgery of the knee. However, data on the normal alignment of the lower extremity in Chinese adults are not available.

METHODS

The axial alignment of the lower extremity in twenty-five adult male and twenty-five adult female volunteers of southern Chinese origin was measured on weight-bearing radiographs of the entire lower limb. The mean age was twenty-four years for the male volunteers and twenty-three years for the female volunteers. The results were compared with those of two similar studies of white volunteers in the United States.

RESULTS

The medial inclination of the tibial plateau in the Chinese subjects (mean and standard deviation, 5.4 +/- 2.5 degrees for women and 4.9 +/- 2.3 degrees for men) was greater than the commonly reported 3 degrees. The extremities of the Chinese women were found to have a mean of 2.2 +/- 2.5 degrees of varus alignment, and those of the Chinese men had a mean of 2.2 +/- 2.7 degrees of varus alignment.

CONCLUSIONS

Compared with the white subjects described in the studies by Moreland et al. and Hsu et al., the Chinese subjects had significantly larger medial inclination of the knee joint (knee-joint obliquity) (p < 0.005) and the female Chinese subjects had significantly more varus alignment of the lower extremity (p < 0.025).

CLINICAL RELEVANCE

Five degrees of external rotation of the femoral component, instead of the commonly reported 3 degrees, may be required to obtain a rectangular flexion gap in total knee arthroplasty in Chinese patients. The racial difference in the knee-joint obliquity may contribute to the racial difference in the ratio of knee osteoarthritis to hip osteoarthritis. Additional studies are necessary to confirm this relationship.

[Bacterial genetic diversity in soils and their correlation with vegetation]

Soil is an important epicenter of biodiversity. Human activity has threatened such biodiversity through vegetation shift. As the major type of microbes, bacteria have played key roles in material cycling. Since simple morphological characters and the failure of the major portion of bacteria in surviving artificial cultivation have hindered bacterial diversity from analyses using traditional taxonomic approaches, bacterial diversity and its correlation with vegetation is less understood. In order to detour cultivation, tag serial sequencing strategy was developed in this study, in which a 26 base pair highly variable region has been chosen from 16S ribosomal RNA gene as variant-representing tags, ligated into serials and sequenced. Molecular bacterial diversity in soils has been determined using tag types, tag frequencies and diversity index as parameters. The correlation of bacterial diversity with vegetation has been explored as well. Bacterial diversity and differentiation correlate highly with contents of organic matter and nitrogen of soils and further vegetation.

Characterization of the major DNA adducts in the liver of rats chronically exposed to tamoxifen for 18 months

Our previous study has shown that chronic exposure to tamoxifen (TAM) induced formation of high levels of DNA adducts in the liver, the target tissue of TAM-induced carcinogenesis in rats. One of the major DNA adducts (spot 1), as detected by 32P-postlabeling, accounted for 53% of the total adducts. To characterize this major adduct, the current study has compared spot 1 with two previously identified TAM-DNA adducts, i.e. alpha-TAM-N2-deoxyguanine (alpha-TAM-N2-dG) and alpha-N-desmethyl TAM-N2-deoxyguanine (alpha-N-dmTAM-N2-dG) by various rechromatography methods. It was found that spot 1 was further resolved into two fractions during rechromatography analysis, one fraction co-migrated with the alpha-TAM-N2-dG and the other fraction co-migrated with the alpha-N-dmTAM-N2-dG. These findings have demonstrated that chronic exposure to tamoxifen induced the same major DNA adducts, i.e. alpha-TAM-N2-dG and alpha-N-dmTAM-N2-dG as those detected in acutely exposed rats.

Cyclosporin-induced dyslipoproteinemia is associated with selective activation of SREBP-2

The use of cyclosporin A has contributed greatly to the success of organ transplantation. However, cyclosporin-associated side effects of hypertension, nephrotoxicity, and dyslipoproteinemia have tempered these benefits. Cyclosporin-induced dyslipoproteinemia may be an important risk factor for the accelerated atherosclerosis observed posttransplantation. Using a mouse model, we treated Swiss-Webster mice for 6 days with a daily dose of 20 microg/g body wt of cyclosporin and observed significant elevations of plasma cholesterol, triglyceride, and apolipoprotein B (apoB) levels relative to vehicle-alone treated control animals. Measurement of the rate of secretion of very low-density lipoprotein (VLDL) by the liver in vivo showed that cyclosporin treatment led to a significant increase in the rate of hepatic VLDL triglyceride secretion. Total apoB secretion was unaffected. Northern analysis showed that cyclosporin A treatment increased the abundance of hepatic mRNA levels for a number of key genes involved in cholesterol biosynthesis relative to vehicle-alone treated animals. Two key transcriptional factors, sterol regulatory element-binding protein (SREBP)-1 and SREBP-2, also showed differential expression; SREBP-2 expression was increased at the mRNA level, and there was an increase in the active nuclear form, whereas the mRNA and the nuclear form of SREBP-1 were reduced. These results show that the molecular mechanisms by which cyclosporin causes dyslipoproteinemia may, in part, be mediated by selective activation of SREBP-2, leading to enhanced expression of lipid metabolism genes and hepatic secretion of VLDL triglyceride.

Dural closure with nonpenetrating clips prevents meningoneural adhesions: an experimental study in dogs

OBJECTIVE

Meningospinal and cranial dural adhesions were compared in a canine model, after duraplasty using nonpenetrating clips or penetrating needles and sutures.

METHODS

Fourteen dogs underwent bilateral craniotomies and duraplasties, with implantation of dural prostheses (DuraGuard; Biovascular Corp., Minneapolis, MN), using either 6-0 silk sutures or titanium clips (DuraClose; Surgical Dynamics, Norwalk, CT). Fourteen other dogs underwent L3-L4 laminectomies; three longitudinal dural incisions were closed with 6-0 silk sutures, 6-0 polyglactin 910 (Vicryl) sutures, or clips. Groups of eight dogs (four cranially treated and four spinally treated) were killed 6, 12, 24, and 52 weeks after surgery, and specimens were collected for study after perfusion and fixation (two cranial and two spinal dural reconstructions at 52 wk). Evaluations included assessment of the appearance of approximated dural margins and responses to clips, sutures, and dural prostheses (inflammation, foreign body reaction, fibrosis, and severity of meningospinal/meningocerebral adhesions). Data were evaluated using the Wilcoxon signed-rank and McNemar tests.

RESULTS

Duraplasties with clips displayed significantly less extensive acute and chronic inflammation, foreign body reaction, and meningoneural adhesions than did repairs with needles and sutures.

CONCLUSION

This report is the first long-term experimental study comparing two fundamentally different methods for dural repair in a relevant animal model.

Effects of fenfluramine combined with electroacupuncture on monoamine release in periaqueductal gray of rat brain

AIM

To study the changes of monoamines in ventrolatoral periaqueductal gray of rat brain before and after electroacupuncture (EA) analgesia (EAA) was enhanced by fenfluramine (Fen), a 5-hydroxytryptamine (5-HT) releaser.

METHODS

Monoamines were collected by in vivo microdialysis and measured by HPLC connected with electrochemical detector.

RESULTS

The level of norepinephrine (Nor) after EA was decreased (P < 0.05 vs NS group). The contents of 5-HT, 5-hydroxyindol acetic acid (5-HIAA), dopamine (DA), and homovanillic acid (HVA) in periaqueductal gray dialysate were increased (P < 0.05 vs NS group). When Fen was combined with EA, the level of 5-HT and 5-HIAA were further increased (P < 0.05 vs NS + EA group). There was no obvious change of Nor, DA, and HVA.

CONCLUSION

Fen potentiating EAA may be related to further activation of serotoninergic system.

Applying neural networks as software sensors for enzyme engineering

The on-line control of enzyme-production processes is difficult, owing to the uncertainties typical of biological systems and to the lack of suitable on-line sensors for key process variables. For example, intelligent methods to predict the end point of fermentation could be of great economic value. Computer-assisted control based on artificial-neural-network models offers a novel solution in such situations. Well-trained feedforward-backpropagation neural networks can be used as software sensors in enzyme-process control; their performance can be affected by a number of factors.

Neural networks as "software sensors" in enzyme engineering

Industrial applications of enzyme technology are rapidly increasing. On-line control of enzyme production processes, however, is difficult owing to the uncertainties typical of biological systems and to the lack of suitable on-line sensors for key process variables and quality attributes. We demonstrate that well-trained feedforward backpropagation neural networks with one hidden layer can be employed to overcome such problems with no need for a priori knowledge of the relationships of the process variables involved. Neural network programs were written in Microsoft Visual C++ for Windows and implemented in a personal computer. The goodness of fit of the trained neural network to the reference data was determined by the coefficient of determination, R2. Case studies of beta-galactosidase, glucoamylase, lipase, and xylanase production processes will be used as examples.

The distribution of the matricellular protein thrombospondin 2 in tissues of embryonic and adult mice

Mice that lack the matricellular protein thrombospondin 2 (TSP2) develop a pleiotropic phenotype characterized by morphological changes in connective tissues, an increase in vascular density, and a propensity for bleeding. Furthermore, dermal cells derived from TSP2-null mice display adhesion defects, a finding that implicates TSP2 in cell-matrix interactions. To gain a better understanding of the participation of TSP2 in the development and maturation of the mouse, we examined its distribution in embryonic and adult tissues. Special attention was paid to the presence of TSP2 in collagen fibers, because collagen fibrils in the TSP2-null mouse appear to be irregular in size and contour by electron microscopy. Immunohistochemical analysis of Day 15 and Day 18 embryos revealed TSP2 in areas of chondrogenesis, osteogenesis, and vasculogenesis, and in dermal and other connective tissue-forming cells. Distinctly different patterns of deposition of TSP2 were observed in areas of developing cartilage and bone at Days 15 and 18 of embryonic development. A survey of adult tissues revealed TSP2 in dermal fibroblasts, articular chondrocytes, Purkinje cells in the cerebellum, Leidig cells in the testis, and in the adrenal cortex. Dermal fibroblasts were also shown to synthesize TSP2 in vitro. The distribution of TSP2 during development is in keeping with its participation in the formation of a variety of connective tissues. In adult tissues, TSP2 is located in the pericellular environment, where it can potentially influence the cell-matrix interactions associated with cell movement and tissue repair.

Facilitated vascular anastomoses: the one-shot device

BACKGROUND

A mechanical system for facilitating vascular anastomosis (end-to-side, end-to-end) is described that enables the rapid construction of nonpenetrated, compliant junctions. The instrument (United States Surgical One-Shot system) simultaneously applies either 10 or 12 nonpenetrating, arcuate-legged titanium clips to everted vessel or prosthetic conduit edges.

METHODS AND RESULTS

The instrument has been tested in animals (jugular and femoral vein jump grafts in carotid and femoral arteries, interpositional grafts, 20 pigs) and human cadaveric constructs (saphenous veins to left anterior descending coronary arteries, 20 cases, 5 brachiocephalic access fistulas) as end-to-side constructs. Clipped constructs have equivalent or superior physical properties to control sutured constructs (6-0 polypropylene) as gauged by burst and tensile strength. All studies were performed under Food and Drug Administration Good Laboratory Practice standards, and the device has been approved for marketing by the Food and Drug Administration.

CONCLUSIONS

The device enables rapid and reproducible vascular anastomotic constructs with vessels as small as 1.8 mm outer diameter. The constructs are flanged, interrupted, and nonpenetrated.

A far upstream, cell type-specific enhancer of the mouse thrombospondin 3 gene is located within intron 6 of the adjacent metaxin gene

Thrombospondin 3 (TSP3) is a secreted, pentameric glycoprotein whose regulation of expression and function are not well understood. Mouse Thbs3 is located just downstream from the divergently transcribed metaxin gene (Mtx), which encodes an outer mitochondrial membrane import protein. Although Thbs3 and Mtx share a common promoter region, previous studies showed that Mtx is regulated by proximal elements that had little effect on Thbs3 expression. In this study, transient transfection of rat chondrosarcoma cells and NIH-3T3 fibroblasts demonstrated that Thbs3 is regulated in a cell type-specific manner by a position- and orientation-independent far upstream enhancer located within intron 6 of Mtx. Despite its greater proximity to the transcription start site of Mtx, the Thbs3 enhancer did not have a significant effect on Mtx expression. Two DNA-protein complexes, which were both required for activity, were identified when nuclear extracts were assayed with a probe containing the enhancer sequence. The protein in one of these complexes was identified as Sp1, while the other DNA-protein complex remains uncharacterized. A 6-kilobase pair promoter containing the enhancer was able to direct specific expression of the E. coli lacZ gene in transgenic mice, whereas a 2-kilobase pair promoter that lacked the enhancer was inactive. Thus, despite their close proximity, the genes of the Mtx/Thbs3 gene cluster are regulated independently.

Mice that lack thrombospondin 2 display connective tissue abnormalities that are associated with disordered collagen fibrillogenesis, an increased vascular density, and a bleeding diathesis

Thrombospondin (TSP) 2, and its close relative TSP1, are extracellular proteins whose functions are complex, poorly understood, and controversial. In an attempt to determine the function of TSP2, we disrupted the Thbs2 gene by homologous recombination in embryonic stem cells, and generated TSP2-null mice by blastocyst injection and appropriate breeding of mutant animals. Thbs2-/- mice were produced with the expected Mendelian frequency, appeared overtly normal, and were fertile. However, on closer examination, these mice displayed a wide variety of abnormalities. Collagen fiber patterns in skin were disordered, and abnormally large fibrils with irregular contours were observed by electron microscopy in both skin and tendon. As a functional correlate of these findings, the skin was fragile and had reduced tensile strength, and the tail was unusually flexible. Mutant skin fibroblasts were defective in attachment to a substratum. An increase in total density and in cortical thickness of long bones was documented by histology and quantitative computer tomography. Mutant mice also manifested an abnormal bleeding time, and histologic surveys of mouse tissues, stained with an antibody to von Willebrand factor, showed a significant increase in blood vessels. The basis for the unusual phenotype of the TSP2-null mouse could derive from the structural role that TSP2 might play in collagen fibrillogenesis in skin and tendon. However, it seems likely that some of the diverse manifestations of this genetic disorder result from the ability of TSP2 to modulate the cell surface properties of mesenchymal cells, and thus, to affect cell functions such as adhesion and migration.

Semiquantitative PCR of alpha2 and alpha4 integrin mRNA shows differential response to the transcriptional modulators TGF-beta1 and TPA

The differential expression of VLA integrins in different cell types under different conditions has been mainly studied at the protein level. Since these cell surface proteins have a rather slow turn-over, quantitative changes in their transcription may go unnoticed. The expression of alpha2 and alpha4 mRNA was studied by relative quantitative RT-PCR on Molt-4 (human T-cell lymphoma) and A875 (human melanoma) cells. Modulation of the expression was investigated by treatment with TGF-beta1 and TPA. Stimulation with TGF-beta1 increased the expression of alpha4 in Molt-4 cells and of alpha2 in A875 cells. Treatment with TPA did not alter the expression of alpha4 mRNA on Molt-4 cells but significantly increased their alpha2 expression. Thus, integrin expression can be modulated differentially and this modulation can be reinforced by transcriptional activators.

Expression of preproopiomelanocortin mRNA and preprodynorphin mRNA in brain of spontaneously hypertensive rats

AIM

To compare the expressions of prepropiomelanocortin (POMC) mRNA and preprodynorphin (PPD) mRNA between 16-wk-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY).

METHODS

The expression of POMC mRNA and PPD mRNA were detected with nonradioactive in situ hybridization by digoxigenin-labeled RNA probe.

RESULTS

POMC mRNA mainly was expressed in arcuate nucleus, compared with WKY, SHR had higher level of POMC mRNA (542). PPD mRNA was found in hippocampus, hypothalamus, central gray, nucleus of the solitary tract (NTS), and thoracic spinal cord (T4-T6). Compared with WKY, PPD mRNA level of SHR decreased in dentate gyrus (2342), NTS (381), and medial preoptic area (467); no difference was observed in arcuate nucleus (263), thoracic spinal cord (750-1800) and CA1, CA2, CA3 of hippocampus (1674, 2014, 2626).

CONCLUSION

Increase of POMC mRNA in arcuate nucleus and decrease of PPD mRNA in dentate gyrus of SHR may be associated with the genesis of spontaneous hypertension.

[Effect on intratumoral T lymphocyte and its subset in oral squamous cell carcinoma following immumnochemotherapy]

The relative numbers of CD(3)(+),CD(3)(+),CD(8)(+) and HLA-RD(+) cells in the tumor tissue before and after inductive therapy was counted using immunohistochemical technique of Avidin Biotin-Peroxidase Complex(ABC),and then the effect on local immune cell following two different inductive therapies was comparatively analysed.The results showed that S-PVP therapy could result in significant increasing in numbers of CD(3)(+)and CD(4)(+) cells intratumorally as compared with pre-therapy(P<0.05),and in slignt increasing in numbers of CD(8)(+) and HLA-DR(+) cell,which is no significant difference between pre-and post-therapy.In the PVP group,there was no significant difference in numbers of CD(3)(+),CD(4)(+),CD(8)(+) and HLA-DR(+) cells between pre-and post-treatment.The results suggested that T lymphocyte in the tumor site could significantly increase in numbers following the S-PVP therapy,and PVP chemotherapy did not obviously affect the local cellular immunity.

[Alteration of monoamine contents in microdialysate following droperidol enhanced electroacupuncture]

The monoamine contents in microdialysate from rat brain before and after droperidol (DRO), a dopamine (DA) antagonist, enhanced electroacupuncture-induced analgesia (EA) were measured using techniques of in vivo microdialysis and high performance liquid chromatography with electrochemical detection (HPLC-EC), so as to investigate the monoamine mechanism of the potentiating effect of DRO on acupuncture analgesia (AA). The results showed that the levels of DA and its metabolites homovanillic acid (HVA) in perfusate increased after EA (P < 0.05 or 0.01), and further increased after DRO + EA (P < 0.05 and 0.01, vs EA treatment). A significant decrease in norepinephrine (NE) content after EA (P < 0.01) was observed, but no further change after DRO + EA (P > 0.05, vs EA treatment). The contents of 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindole acetic acid (5-HIAA) we elevated after EA treatment, and a further elevation in 5-HT and 5-HIAA contents induced by DRO + EA was noted. The results in the present study suggest that DRO potentiated AA not only via antagonizing the activity of dopaminergic system, but also by coordinating the activities of other monoamines in the brain.

Nonpenetrating clips for coronary anastomosis

BACKGROUND

A nonsuture clip technique (nonpenetrating titanium clips applied to everted tissue edges at high compressive forces) was used to perform coronary anastomoses in a clinical setting.

METHODS

Clipped coronary anastomoses were performed in 10 patients. The anastomoses incorporated the left internal mammary artery to the left anterior descending artery (n = 1) and the saphenous vein to the right coronary artery (n = 5), the posterior descending artery (n = 2), the diagonal artery (n = 2), and one vein-to-vein proximal anastomosis (n = 1).

RESULTS

The mean duration for completion of the anastomoses was 15 minutes (range, 7 to 20 minutes). This time was reduced from 20 minutes at the beginning of the clinical experience to 7 minutes for the last 3 patients. No technical complication was related to clip application and all patients had uneventful outcomes. Three anastomoses studied by coronary angiography were patent without stenosis.

CONCLUSION

The clipped anastomotic technique has a rapid learning curve, the same safety as suture methods, and the potential for facilitating endoscopic vascular reconstructions.

Cross-species comparison of angiogenesis during the premalignant stages of squamous carcinogenesis in the human cervix and K14-HPV16 transgenic mice

Infection of the human cervix with certain papillomavirus subtypes is associated with the development of neoplastic squamous lesions that can progress to overt cervical malignancies. Recently, multistage squamous carcinogenesis has been achieved in K14-HPV16 transgenic mice, wherein expression of the human papillomavirus (HPV) type 16 early genes is targeted to basal squamous epithelial cells by regulatory elements of the human keratin-14 (K14) promoter. Immunostaining of the endothelial marker vWf revealed a parallel upregulation of angiogenesis during the early neoplastic stages in both human cervix and the epidermis of K14-HPV16 transgenic mice. Moreover, high-grade premalignant lesions and cancers in humans and transgenic mice were characterized by an additional increment in the number of new capillaries and close apposition of the microvasculature to the overlying neoplastic epithelium. Expression of the potent angiogenic factor VEGF was progressively up-regulated during carcinogenesis in both species, correlating with the increased density and altered distribution of the microvasculature. Thus, angiogenesis occurs during the premalignant stages of squamous carcinogenesis in both human cervical disease and a relevant transgenic model and may be controlled by similar molecular mechanisms in both species. These results validate the use of the transgenic model to elucidate the role of angiogenesis during HPV-associated neoplastic progression.

Neural networks as 'software sensors' in enzyme production

Industrial applications of enzyme technology are rapidly increasing. On-line control of enzyme production processes, however, is difficult, owing to the uncertainties typical of biological reactions and to the lack of suitable sensors. We demonstrate that well-trained feedforward backpropagation neural networks with one hidden layer can be employed to overcome such problems with no need for a priori knowledge of the relationships of the process variables involved. Neural network programs were written in Microsoft Visual C+2 for Windows and implemented in a personal computer. The goodness of fit of the trained neural network to the reference data was determined by the coefficient of determination R2. On-line state estimation and multi-step ahead prediction of enzyme activity and biomass concentration, both in a yeast lipase and fungal glucoamylase production could be satisfactorily carried out. Results showed an excellent fit for estimated lipase activity (R2 = 0.988) and biomass concentration (R2 = 0.989). In glucoamylase production, both enzyme activity and biomass concentration could also be reliably predicted for 2 time intervals (10 h) ahead with only on-line measurable parameter values as the input data.