Validation of the

The cluster structure of the neutron-rich isotope ^{10}Be has been probed via the (p,pα) reaction at 150 MeV/nucleon in inverse kinematics and in quasifree conditions. The populated states of ^{6}He residues were investigated through missing mass spectroscopy. The triple differential cross section for the ground-state transition was extracted for quasifree angle pairs (θ_{p},θ_{α}) and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using successively the Tohsaki-Horiuchi-Schuck-Röpke product wave function and the wave function deduced from antisymmetrized molecular dynamics calculations. The remarkable agreement between calculated and measured cross sections in both shape and magnitude validates the molecular structure description of the ^{10}Be ground-state, configured as an α-α core with two valence neutrons occupying π-type molecular orbitals.

[Alterations in erythrocytic oligomeric alpha-synuclein in patients with Parkinson's disease and multiple system atrophy].

Objective: To analyze the content of α-synuclein oligomer(O-α-Syn) in erythrocytes in patients with Parkinson's disease (PD) and multiple system atrophy (MSA) and the correlation with clinical symptoms. Methods: Two hundred and ninety-six PD patients and 85 MSA patients were recruited from the Department of Functional Neurosurgery and Neurology of Xuanwu Hospital, Capital Medical University from July 2020 to October 2021. Four hundred and three healthy controls (HC) were recruited from the Beijing Longitudinal Study of Aging community cohort during the same period. The levels of RBC-O-α-Syn were measured by enzyme-linked immunosorbent assay (ELISA). Univariate linear regression model was used to analyze the correlation between the content of RBD-O-α-Syn and various motor and non-motor functional scores, such as Unified Parkinson Disease Rating Scale (UPDRS) Ⅲ, Unified Multiple System Atrophy Rating Scale (UMSARS) Ⅲ, Mini-Mental State Examination (MMSE), rapid eye movement sleep disorder questionnaire-HongKong(RBDQ-HK) and Montreal Cognitive Assessment (MoCA). Receiver operating characteristic (ROC) curves was used to evaluate the specificity, sensitivity, and the area under the curve (AUC) of RBC-O-α-Syn in distinguishing PD and MSA patients from HC subjects. Results: The average age of HC subjects was (70±8) years old, the average age of PD patients was (64±9) years old, including 115 (38.9%) cases with tremor dominant PD (TD-PD), 132 cases (44.6%) of postural instability disorder predominant PD (PIGD-PD), and 142 cases (48.0%) of patients with H-Y stage 2. UPDRS Ⅲ score was 31.2±17.8. The mean age of MSA patients was (64±9) years, with the mean UMSARS Ⅱ score of 18.9±10.3. The non-motor symptoms of PD and MSA patients were significantly different from those of HC subjects (P<0.001). The levels of RBC-O-α-Syn in PD [(50±17) ng/mg] and MSA [(52±19) ng/mg] were significantly higher than those in HC subjects [(21±10) ng/mg] (P<0.001). The sensitivity and specificity of RBC-O-α-Syn in distinguishing PD patients and HC subjects were 87.16% (95%CI: 82.87%-90.50%) and 86.10% (95%CI: 82.38%-89.14%), with an AUC of 0.933 (95%CI: 0.914-0.951), and the sensitivity and specificity in distinguishing MSA patients and HC subjects were 85.88% (95%CI: 76.93%-91.74%) and 81.39% (95%CI: 77.30%-84.89%), with an AUC of 0.921 (95%CI: 0.884-0.957). The levels of RBC-O-α-Syn in PD patients with rapid eye movement sleep behavior disorder (RBD) were higher than that in PD patients without RBD [(53±16) ng/mg vs (48±17) ng/mg, P=0.029].The content of RBC-O-α-Syn in female PD patients and HC subjects was higher than that in male, but there was no significant difference between subjects of different ages and disease duration (P>0.05). In addition, RBC-O-α-Syn content was positively correlated with UPDRS Ⅲ (r=0.18, P=0.002) and the score of rapid eye movement sleep behavior disorder questionnaire(Hong Kong) (RBDQ-HK)(r=0.19, P<0.001). But there was no correlation with H-Y stage, non-motor symptoms scale (NMSS), MMSE, Moca, Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA) scores (all P>0.05). There was no correlation between RBC-O-α-Syn content and UMSARS Ⅱ, NMSS, MMSE, MoCA, HAMD, HAMA in patients with MSA (all P>0.05). Conclusions: Levels of RBC-O-α-Syn are significantly increased in PD and MSA patients. There are positive correlations between levels of RBC-O-α-Syn and scores of UPDRS Ⅲ and RBDQ-HK.

[Efficacy of alcohol septal ablation in mildly symptomatic or severely symptomatic patients with hypertrophic obstructive cardiomyopathy].

Objective: To compare the prognosis of mildly or severely symptomatic patients with obstructive hypertrophic cardiomyopathy (OHCM) who underwent alcohol septal ablation (ASA). Methods: This retrospective study cohort consisted of patients with OHCM who received ASA treatment in Beijing Anzhen Hospital, Capital Medical University from March 2001 to August 2021. These patients were divided into mildly and severely symptomatic groups according to the severity of clinical symptoms. Long-term follow-up was conducted, and the following data were collected: duration of follow-up, postoperatire treatment, New York Heart Association (NYHA) classification, arrhythmia events and pacemaker implantation, echocardiographic parameters, and cause of death. Overall survival and survival free from OHCM-related death were observed, and the improvement of clinical symptoms and resting left ventricular outflow tract gradient (LVOTG) and the incidence of new-onset atrial fibrillation were evaluated. The Kaplan-Meier method and log-rank test were used to determine and compare the cumulative survival rates of the different groups. Cox regression analysis models were used to determine predictors of clinical events. Results: A total of 189 OHCM patients were included in this study, including 68 in the mildly symptomatic group and 121 in the severely symptomatic group. The median follow-up of the study was 6.0 (2.7, 10.6) years. There was no statistical difference in overall survival between the mildly symptomatic group (5-year and 10-year overall survival were 97.0% and 94.4%, respectively) and the severely symptomatic group (5-year and 10-year overall survival were 94.2% and 83.9%, respectively, P=0.405); there was also no statistical difference in survival free from OHCM-related death between the mildly symptomatic group (5-year and 10-year survival free from HCM-related death were 97.0% and 94.4%, respectively) and the severely symptomatic group (5-year and 10-year survival free from HCM-related death were 95.2% and 92.6%, respectively, P=0.846). In the mildly symptomatic group, NYHA classification was improved after ASA (P<0.001), among which 37 patients (54.4%) were in NYHA class Ⅰ, and the resting left ventricular outflow tract gradient (LVOTG) decreased from 67.6 (42.7, 90.1) mmHg (1 mmHg=0.133 kPa) to 24.4 (11.7, 35.6) mmHg (P<0.001). In severely symptomatic group, NYHA classification was also improved post ASA (P<0.001), among which 96 patients (79.3%) improved by at least one NYHA classification, and the resting LVOTG decreased from 69.6 (38.4, 96.1) mmHg to 19.0 (10.6, 39.8) mmHg (P<0.001). The incidence of new-onset atrial fibrillation was similar between the mildly and severely symptomatic groups (10.2% vs. 13.3%, P=0.565). Cox multivariate regression analysis showed that age was an independent predictor of all-cause mortality in OHCM patients post ASA (HR=1.068, 95%CI 1.002-1.139, P=0.042). Conclusions: Among patients with OHCM treated with ASA, overall survival and survival free from HCM-related death were similar between mildly symptomatic group and severely symptomatic group. ASA therapy can effectively relieve resting LVOTG and improve clinical symptoms in mildly or severely symptomatic patients with OHCM. Age was an independent predictor of all-cause mortality in OHCM patients post ASA.

Observation of a Strongly Isospin-Mixed Doublet in

ß decay of proton-rich nuclei plays an important role in exploring isospin mixing. The ß decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055 keV and two new high-lying states at 13 380 and 11 912 keV in ^{26}Si are unambiguously identified through ß-delayed two-proton emission (ß2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P ß decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21) keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in ß-decay experiments.

Observation of a correlated free four-neutron system.

A long-standing question in nuclear physics is whether chargeless nuclear systems can exist. To our knowledge, only neutron stars represent near-pure neutron systems, where neutrons are squeezed together by the gravitational force to very high densities. The experimental search for isolated multi-neutron systems has been an ongoing quest for several decades1, with a particular focus on the four-neutron system called the tetraneutron, resulting in only a few indications of its existence so far2-4, leaving the tetraneutron an elusive nuclear system for six decades. Here we report on the observation of a resonance-like structure near threshold in the four-neutron system that is consistent with a quasi-bound tetraneutron state existing for a very short time. The measured energy and width of this state provide a key benchmark for our understanding of the nuclear force. The use of an experimental approach based on a knockout reaction at large momentum transfer with a radioactive high-energy 8He beam was key.

[Therapeutic effects of alcohol septal ablation in mildly symptomatic patients with hypertrophic obstructive cardiomyopathy].

Objective: To observe the therapeutic effects of alcohol septal ablation (ASA) in mildly symptomatic patients (NYHA class Ⅱ) with hypertrophic obstructive cardiomyopathy(HOCM). Methods: This retrospective study included 150 mildly symptomatic patients with HOCM hospitalized in Beijing Anzhen Hospital affiliated to Capital Medical University from March 2001 to December 2017, consisting of medical therapy group (n=102) and ASA group (n=48). Baseline clinical data were collected, patients were followed up to a mean of 6.0 (3.5, 8.1) years. Overall and HCM-related mortality events (including chronic heart failure, atrial fibrillation related stroke, sudden cardiac death) were observed in the two groups. Moreover, the improvement of NYHA function classification and left ventricular outflow tract gradient (LVOTG) were also evaluated. Survival analysis was performed by Kaplan-Meier method. Results: Age of this cohort was (52.9±14.5)years, 92 cases(61.3%) were male. In the follow-up, LVOTG was reduced from (85.8±35.4)mmHg (1 mmHg=0.133 kPa) to (27.7±19.8)mmHg (P<0.001) in the ASA group, and from (66.3±35.0)mmHg to (56.5±27.7)mmHg in medical therapy group(P<0.01). At the last clinical follow-up, there were 32 patients (66.7%) whose LVOTG were<30 mmHg, septal thickness decreased from (20.3±3.8)mm to (16.1±3.4)mm (P<0.001), NYHA classification was also remarkably improved (P<0.001). New-onset atrial fibrillation tended to be lower in the ASA group compared to medical therapy group (9.3%(4/43) vs. 20.8%(20/96),P=0.096). Eleven patients (10.8%) in the medical therapy group and 2 patients (4.2%) in the ASA group died during the follow-up. One patient received pacemaker during the peri-procedural period, 1 patient was implanted with two-chamber pacemaker due to Ⅲ° atrioventricular block at 10 years after operation in the ASA group. Survival free of all-cause mortality of ASA group at 5 and 10 years was 97.9% and 97.9%, respectively, which was comparable to the medical therapy group (P=0.231). Survival free of HCM-related mortality was similar between the two groups (P=0.397). Conclusions: Compared with medical therapy in mildly symptomatic patients with HOCM, long-term survival rate is similar after ASA. Meanwhile, ASA can remarkably reduce LVOTG and improve the clinical status of the patients. Therefore, ASA may be used as an alternative therapy for mildly symptomatic HOCM patients.

[Effects of reduced portosystemic flow on hepatic myelopathy in patients with cirrhosis after TIPS].

Objective: To investigate the impact of a reduced portacaval shunt on hepatic myelopathy (HM) in patients with cirrhosis after a transjugular intrahepatic portosystemic shunt (TIPS). Methods: Patients who developed HM after receiving TIPS at the First Affiliated Hospital of Xi'an Jiaotong University from January 2013 to June 2018 were retrospectively analyzed. HM severity was quantified by clinical spasticity index (CSI) and Fugl-Meyer Assessment (FMA) of the lower extremity. Clinical manifestations were combined with grades Ⅰ-Ⅳ. HM patients were divided into drug treatment (group A) and flow restriction group (group B) according to different treatment methods. The changes in CSI and FMA of the lower extremity after treatment were statistically analyzed in the two groups. P<0.05 was considered a statistically significant difference. Results: A total of 421 cases of cirrhosis who underwent TIPS were enrolled. Among them, 30 developed HM, with 22 in group A and 8 in group B. The incidence of HM after TIPS surgery was about 7.13%. After treatment, CSI was gradually increased and FMA of lower extremity was gradually decreased in group A, while vice-versa in group B. CSI in the two groups were differed significantly at 6, 12, 18, and 24 months after treatment (P<0.05), while the difference in FMA of the lower extremity was statistically significant at 12, 18, and 24 months after treatment (P<0.05). CSI was decreased and FMA of lower extremity was increased after treatment in patients with group A HM grade I. CSI, and FMA of lower extremity changes were statistically significant (P<0.05) when compared with patients with HM grades Ⅱ-Ⅳ. The incidence of hepatic encephalopathy was significantly lower in group B than that in group A (P=0.034), but there was no statistically significant difference between the two groups in the incidence of gastrointestinal bleeding, ascites, infection, MELD score and mortality. Conclusion: A reduced portacaval shunt can improve HM in patients with liver cirrhosis after TIPS, and drug therapy alone is effective for patients with early HM grade I.

Large Isospin Asymmetry in

ß-delayed one-proton emissions of ^{22}Si, the lightest nucleus with an isospin projection T_{z}=-3, are studied with a silicon array surrounded by high-purity germanium detectors. Properties of ß-decay branches and the reduced transition probabilities for the transitions to the low-lying states of ^{22}Al are determined. Compared to the mirror ß decay of ^{22}O, the largest value of mirror asymmetry in low-lying states by far, with δ=209(96), is found in the transition to the first 1^{+} excited state. Shell-model calculation with isospin-nonconserving forces, including the T=1, J=2, 3 interaction related to the s_{1/2} orbit that introduces explicitly the isospin-symmetry breaking force and describes the loosely bound nature of the wave functions of the s_{1/2} orbit, can reproduce the observed data well and consistently explain the observation that a large δ value occurs for the first but not for the second 1^{+} excited state of ^{22}Al. Our results, while supporting the proton-halo structure in ^{22}Al, might provide another means to identify halo nuclei.

Cost analysis of oral and maxillofacial free flap reconstruction for patients at an institution in China.

Free flap transplantation has become a mainstay for the restoration of oral and maxillofacial defects. However, the complexity of the surgical procedure and long hospitalization time result in high hospitalization costs. This study was performed to retrospectively analyse the composition of hospitalization expenses and factors influencing this for 507 patients who underwent oral and maxillofacial free flap transplantation at a representative medical institution in China. The aim was to provide evidence for the reasonable control of expenditure and effective utilization of medical resources, and to gain an indirect reflection of the healthcare model characteristics of public hospitals in China. The average hospitalization cost was found to be US$ 9265±2284. Factors affecting hospitalization expenses were the type of free flap, tracheotomy, postoperative complications, and length of stay. The largest proportion of hospitalization expenses was the cost of materials (44.94%). Although the total hospitalization cost was lower than that in Western countries, the medical burden of patients was higher, and the corresponding medical charges do not fully reflect the value of medical services. We recommend reducing hospitalization expenses and the medical burden by shortening the hospital stay, selecting reasonably priced medical materials, strengthening airway management of patients undergoing tracheotomy, and enhancing the control and treatment of comorbidities in order to reduce the incidence of postoperative complications.

[Central venous-arterial carbon dioxide tension to arterial-central venous oxygen content ratio combined with lactate clearance rate as early resuscitation goals of septic shock].

Objective: To investigate the prognostic significance of central venous-arterial carbon dioxide tension to arterial-venous oxygen content ratio (Pcv-aCO(2)/Ca-cvO(2)) combined with lactate clearance rate (LCR) as early resuscitation goals of septic shock. Methods: One hundred and forty-five septic shock patients admitted to Second Department of Critical Care Medicine of Lanzhou University Second Hospital from March 2013 to May 2017 were enrolled in this study.All septic shock patients received an initial resuscitation therapy according to early goal-directed therapy.The arterial and central venous blood gases were measured simultaneously at baseline (T0) and 6 hours after resuscitation (T6). Pcv-aCO(2)/Ca-cvO(2) and LCR were calculated.Patients were classified into four groups according to Pcv-aCO(2)/Ca-cvO(2) and LCR at T6: group A, Pcv-aCO(2)/Ca-cvO(2)>1.8 and LCR<30%; group B, Pcv-aCO(2)/Ca-cvO(2)>1.8 and LCR≥30%; group C, Pcv-aCO(2)/Ca-cvO(2)≤1.8 and LCR<30%; group D, Pcv-aCO(2)/Ca-cvO(2)≤1.8 and LCR≥30%.General demographics, hemodynamic parameters, oxygen metabolism parameters, acute physiology and chronic health evaluation (APACHE Ⅱ) scores, sequential organ failure assessment (SOFA) scores, length of intensive care unit (ICU) stay, and 28-day mortality rate were compared among the 4 groups.A Kaplan-Meier curve showed the survival probabilities at day 28 using a log-rank test for multiple comparisons.Parameters were introduced into a Cox's proportional hazards regression model to analyze the prediction of 28-day mortality.Receiver operating characteristics (ROC) curves were constructed to evaluate the ability of Pcv-aCO(2)/Ca-cvO(2), LCR, Pcv-aCO(2)/Ca-cvO(2) combined with LCR at T6 to predict 28-day mortality. Results: Compared with patients in group A, patients from group D had the lower APACHE Ⅱ and SOFA score at day 3 (t=-2.909, -3.630, both P<0.05), shorter ICU stay (t=-2.575, P=0.011), and lower mortality rate at day 28 (χ(2)=3.124, P=0.011). Survival curves up to day 28, illustrated by Kaplan-Meier method, showed that group A had the shortest median survival time (χ(2)=10.332, P=0.016), difference between group A and group D was statistically significant (χ(2)=8.304, P=0.004). The Cox regression analysis revealed that Pcv-aCO(2)/Ca-cvO(2) (RR=3.888, 95%CI: 2.443-6.189, P<0.001) and LCR (RR=0.073, 95%CI: 0.008-0.640, P=0.018) at T6 were independent predictors of 28-day mortality.The area under ROC curve for Pcv-aCO(2)/Ca-cvO(2) combined with LCR (0.919, 95%CI: 0.862-0.958) was significantly greater than whether Pcv-aCO(2)/Ca-cvO(2) (0.862, 95%CI: 0.795-0.914) or LCR (0.820, 95%CI: 0.748-0.879) alone (Z=2.032, 2.364, both P<0.05). Conclusion: Combination of Pcv-aCO(2)/Ca-cvO(2) and LCR is better than single parameter to predict the risk of adverse outcomes of septic shock patients, and may provide useful information for assessing the adequacy of resuscitation at early stage of septic shock.

Ultrafast consolidation of bulk nanocrystalline titanium alloy through ultrasonic vibration.

Nanocrystalline (NC) materials have fascinating physical and chemical properties, thereby they exhibit great prospects in academic and industrial fields. Highly efficient approaches for fabricating bulk NC materials have been pursued extensively over past decades. However, the instability of nanograin, which is sensitive to processing parameters (such as temperature and time), is always a challenging issue to be solved and remains to date. Herein, we report an ultrafast nanostructuring strategy, namely ultrasonic vibration consolidation (UVC). The strategy utilizes internal friction heat, generated from mutually rubbing between Ti-based metallic glass powders, to heat the glassy alloy rapidly through its supercooled liquid regime, and accelerated viscous flow bonds the powders together. Consequently, bulk NC-Ti alloy with grain size ranging from 10 to 70 nm and nearly full density is consolidated in 2 seconds. The novel consolidation approach proposed here offers a general and highly efficient pathway for manufacturing bulk nanomaterials.

A new insight into high-strength Ti62Nb12.2Fe13.6Co6.4Al5.8 alloys with bimodal microstructure fabricated by semi-solid sintering.

It is well known that semi-solid forming could only obtain coarse-grained microstructure in a few alloy systems with a low melting point, such as aluminum and magnesium alloys. This work presents that semi-solid forming could also produce novel bimodal microstructure composed of nanostructured matrix and micro-sized (CoFe)Ti2 twins in a titanium alloy, Ti62Nb12.2Fe13.6Co6.4Al5.8. The semi-solid sintering induced by eutectic transformation to form a bimodal microstructure in Ti62Nb12.2Fe13.6Co6.4Al5.8 alloy is a fundamentally different approach from other known methods. The fabricated alloy exhibits high yield strength of 1790 MPa and plastic strain of 15.5%. The novel idea provides a new insight into obtaining nano-grain or bimodal microstructure in alloy systems with high melting point by semi-solid forming and into fabricating high-performance metallic alloys in structural applications.

Inhibition of hepatic fibrosis with artificial microRNA using ultrasound and cationic liposome-bearing microbubbles.

We sought to investigate the antifibrotic effects of an artificial microRNA (miRNA) targeting connective tissue growth factor (CTGF) using the ultrasound-targeted cationic liposome-bearing microbubble destruction gene delivery system. Cationic liposomes were conjugated with microbubbles using a biotin-avidin system. Plasmids carrying the most effective artificial miRNA sequences were delivered by ultrasound-targeted cationic liposome-bearing microbubble destruction gene delivery system to rats with hepatic fibrosis. The results show that this method of gene delivery effectively transported the plasmids to the rat liver. The artificial miRNA reduced hepatic fibrosis pathological alterations as well as the protein and mRNA expressions of CTGF and transforming growth factor ß1. Furthermore, the CTGF gene silencing decreased the levels of type I collagen and α-smooth muscle actin (P<0.01). These data suggest that delivery of an artificial miRNA targeted against CTGF using ultrasound-targeted cationic liposome-bearing microbubble destruction may be an efficacious therapeutic method to ameliorate hepatic fibrosis.

Abrogated expression of DEC1 during oesophageal squamous cell carcinoma progression is age- and family history-related and significantly associated with lymph node metastasis.

BACKGROUND: Oesophageal squamous cell carcinoma (SCC) causes the highest number of cancer deaths in some regions of Northern China. Previously, we narrowed down a critical region at 9q33-34, identified to be associated with tumour-suppressive function of deleted in oesophageal cancer 1 (DEC1) in oesophageal SCC. METHODS: We generated DEC1 antibody and constructed tissue microarrays (TMAs) utilising tissue specimens from Henan, a high-risk region for oesophageal SCC, to investigate the importance of DEC1 expression in this cancer. RESULTS: Tissue microarray immunohistochemical staining reveals significant loss of DEC1 from hyperplasia, to tumour, and to lymph node metastasis. In addition, the loss of DEC1 in tumour is age-dependent. Interestingly, there is significant abrogation of DEC1 expression in patients with a family history of oesophageal SCC. Deleted in oesophageal cancer 1 localises to both the cytoplasm and nucleus. The vesicular pattern of DEC1 in the cytoplasm appears to localise at the Golgi and Golgi-endoplasmic reticulum intermediate compartment. CONCLUSION: This is the first TMA study to suggest a clinical association of DEC1 in lymph node metastatic oesophageal SCC, early onset oesophageal SCC and familial oesophageal SCC development. Subcellular localisation of DEC1 and its expression in oesophageal SCC tissues provide important insight for further deciphering the molecular mechanism of DEC1 in oesophageal SCC development.

Selective adsorption of Mycobacterium Phlei on pyrite and sphalerite.

The adsorption of Mycobacterium Phlei cells on the surfaces of pyrite and sphalerite was studied as functions of time and pH. The results indicated that a higher amount of cells adsorbing onto pyrite compared with that onto sphalerite under neutral and alkaline conditions, and it was also observed from photographs of scanning electron micrograph. To gain a better insight into the mechanisms of differential adsorption, the functional groups on cell surfaces and the chemical states of each element on mineral surfaces before and after interaction with bacterial cells were investigated. The results showed that many groups presented on cells surface, such as C-O-H, C-O-C, C=O, C-N, N-H and P=O. The change in state of each element on pyrite and sphalerite surfaces after interaction with bacterial cells revealed that there were chemical reactions between metal ions and S on mineral surface and atoms like N, O, P, etc. on cell surface, and the shifts in binding energy of each element on pyrite surface is larger than that of sphalerite. Possible mechanisms for selective adsorption of bacterial cells onto pyrite and sphalerite were discussed in the latter part of this paper.

Unique histological features of the left atrial posterior wall.

The left atrial posterior wall (LAPW) plays a critical role in atrial fibrillation, but the underlying mechanism remains unclear. In the present study, we sought to characterize the histological features of the LAPW. Different atrial regions were dissected from hearts of normal Sprague-Dawley rats and humans. Haematoxylin/eosin and van Gieson staining were used to analyse atrial cardiomyocyte arrangement and collagen distribution, respectively. Intercellular junctions were evaluated by transmission electron microscopy. In contrast with other atrial regions, the LAPW exhibited more disorganized cardiomyocytes, larger intercellular spaces and variable myocardial fibre arrangement. The proportion of collagen was significantly higher in the LAPW than in other atrial regions. Interestingly, desmosomes were sparse along with intercellular gaps in the LAPW. In summary, distinct disarrangement of cardiomyocytes and an abundance of collagen exist in the LAPW. The sparsity of desmosomes in the LAPW may be related to the heterogeneous distribution and separation of atrial myocytes.

Temporal and spatial distribution patterns of heavy metals in soil at a long-standing sewage farm.

Australia's oldest sewage farm in Werribee, Victoria is a significant public asset with more than 110 years of history and it now treats half of Melbourne's municipal sewage. Currently three parallel methods, i.e. lagoon, land filtration and grass filtration were used to treat raw sewage from Melbourne. The land filtration area is soil-pasture-cattle complex system and it operates on 3,633 ha of permanent pastures for livestock grazing. The land filtration area by intermittent irrigation of sewage occurs during the months of high evaporation from October to April. The monitoring study was aimed to find out the temporal and spatial distribution patterns of heavy metals in the soil at land filtration area in the long standing sewage farm. The monitoring results show that the temporal distribution patterns of Cd, Cr, Cu, Ni, Pb and Zn follow the exponential regression equations in soil layer 0-20 cm and the linear equations in soil layer 20-40 cm respectively. The accumulated concentrations of heavy metals in the soils are high enough for the land to be considered contaminated. The exponential trend of heavy metal of soil in land filtration area should be controlled immediately by soil remediation or by change of treatment process of flow configuration.

Risk assessment of cadmium-contaminated soil on plant DNA damage using RAPD and physiological indices.

Impact assessment of contaminants in soil is an important issue in environmental quality study and remediation of contaminated land. A random amplified polymorphic DNA (RAPD) 'fingerprinting' technique was exhibited to detect genotoxin-induced DNA damage of plants from heavy metal contaminated soil. This study compared the effects occurring at molecular and population levels in barley seedlings exposed to cadmium (Cd) contamination in soil. Results indicate that reduction of root growth and increase of total soluble protein level in the root tips of barley seedlings occurred with the ascending Cd concentrations. For the RAPD analyses, nine 10-base pair (bp) random RAPD primers (decamers) with 60-70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 129 RAPD fragments of 144-2639 base pair in molecular size in the root tips of control seedlings. Results produced from nine primers indicate that the changes occurring in RAPD profiles of the root tips following Cd treatment included alterations in band intensity as well as gain or loss of bands compared with the control seedlings. New amplified fragments at molecular size from approximately 154 to 2245 bp appeared almost for 10, 20 and 40 mg L(-1) Cd with 9 primers (one-four new polymerase chain reaction, (PCR) products), and the number of missing bands enhanced with the increasing Cd concentration for nine primers. These results suggest that genomic template stability reflecting changes in RAPD profiles were significantly affected and it compared favourably with the traditional indices such as growth and soluble protein level at the above Cd concentrations. The DNA polymorphisms detected by RAPD can be applied as a suitable biomarker assay for detection of the genotoxic effects of Cd stress in soil on plants. As a tool in risk assessment the RAPD assay can be used in characterisation of Cd hazard in soil.

The effects of contacts and ambipolar electrical transport in nitrogen doped multiwall carbon nanotubes.

The electrical transport properties of pristine single wall carbon nanotubes (SWCNTs) and lower nitrogen content doped multiwall carbon nanotubes (MWCNTs) (lower than in the experiments of Xiao et al (2005 J. Am. Chem. Soc. 127 8614)) in contact with Au and Pt were studied. Compared with pristine SWCNTs, the Fermi level of the lower nitrogen content doped MWCNTs also moved to the valence band edge with the contact metal's work function increasing. In contrast to Derycke et al' s results (2002 Appl. Phys. Lett. 80 2773), the lower nitrogen content doped MWCNTs exhibited ambipolar behavior, and increasing the doping level led to a reduction of the Schottky barrier height of electrons. Consistent with theoretical calculations, the results support the opinion that the degree of Fermi level pinning is minor for doped carbon nanotubes.