Flow pattern analysis of a full-scale expanded granular sludge bed-type reactor under different organic loading rates

The hydraulic characteristics of a lab-scale and a full-scale (275 m(3)) expanded granular sludge bed (EGSB)-type reactor under different organic loading rates varying from 10 kg COD m(-3)d(-1) to 45 kg COD m(-3)d(-1) were investigated. A modified combined model composed of two completely mixing regions and a plug flow region was sufficient for simulating the flow pattern of a full-scale EGSB-type reactor. Moreover, the outputs fitted the measured tracer distribution results well. The simplified model structure was in very good agreement with the physical structure of a full-scale EGSB-type reactor. The upflow (liquid+gas) velocity, high concentration of granular sludge, and gas hold-up effect may contribute to the generation of dead spaces (maximum of 19.5%). The bed expansion characteristics indicated that the sludge bed of the EGSB-type reactor performed as a suspended bed, in which the bed expansion was controlled between 20% and 30%, rather than the usually considered expanded bed.

Time-dependent theoretical model for terahertz wave detector using a parametric process

We have presented a time-dependent theoretical model to describe the time behavior of a quasi-monochromatic nanosecond terahertz detector reported by Guo et al. [Appl. Phys. Lett. 93, 021106 (2008)]. The temporal input-output characteristic of the detector is investigated numerically by taking the system parameters close to the experimental ones, and the calculated pulse width for the incident terahertz wave agrees well with the experimental one. Our results demonstrate that the energy and width of an output idler wave pulse are proportional to those of the incident terahertz wave pulse. This study provides a strict theoretical basis and could be used to guide the design and optimization for the highly sensitive coherent terahertz detector.

Allelic differentiation of Kunitz trypsin inhibitor in wild soybean (Glycine soja)

Soybean Kunitz trypsin inhibitor (SKTI) has several polymorphic types, which are controlled by co-dominant multiple alleles at a single locus. Of these types, Tia and Tib are predominant types, and there are nine differences in amino acids between Tia and Tib. Recently, an intermediate transitional type (Tibi5) between them was detected. However, other transitional types have not been detected despite surveys of many cultivated and wild soybeans. One of the reasons why other transitional variants have not been found is inferred to be due to the difficulty of the detection of SKTI protein variants by polyacrylamide gel electrophoresis (PAGE). To detect novel variants of SKTI, nucleotide sequence analysis in addition to PAGE was carried out. Four new variants were found from many Japanese wild soybeans. Of these variants, three (designated as Tiaa1, Tiaa2, Tiab1) were detected through gene sequence analysis on wild soybeans having the same electrophoretic mobility as Tia, and one (Tig) was detected through PAGE. The Tig variant showed a slightly lower electrophoretic mobility than Tic. The nucleotide sequences of Tig were identical to those of Tib except for one T-->C transitional mutation at position +340. The sequences of Tiaa1 and Tiaa2 genes were identical to those of Tia with the exception of a G-->A mutation at position +376 and a T-->C mutation at +404, respectively. The sequence of Tiab1 differed from Tia by three nucleotides: C-->A at position +331, T-->C at +459 and A-->G at +484. Of the three nucleotide changes, two were common to Tiab1, Tibi5 and Tib, suggesting that Tiab1 is an intermediate transitional type between Tia and Tib. Our results suggest that Tib type has been differentiated through a series of mutations from Tia before the domestication of cultivated soybean.

Steroid Withdrawal Increases Risk of Acute Rejection but Reduces Infection: A Meta-Analysis of 1681 Cases in Renal Transplantation

OBJECTIVE

To evaluate the safety of steroid withdrawal in renal transplantation recipients.

METHODS

These following databases were searched: Medline (1966 to September 2005), OVID (1966 to 2004), Embase (1984 to 2004), Cochrane library (issue 4, 2005), Highwire (1849 to September 2005), American Transplant Congress (2005), Chinese Biomedicine database (CBM 1994 to 2005). The safety was measured by the following factors: patient and graft survival, acute rejection, chronic rejection, infection, serum creatinine. We performed meta-analysis by using Revman 4.2.7.

RESULTS

Nine randomized clinical trials were identified to have a steroid withdrawal and a steroid continuing group. They included 1681 patients: 845 with steroid withdrawal and 836 with continuing steroid. The risk of acute rejection after steroid withdrawal was two times higher than steroid-continuing group (RR 2.05; 95% confidence interval [CI]: 1.54, 2.72; P < .00001), while the incidence of opportunistic infection and urinary tract infection of steroid withdrawal group were lower than the control group (RR 0.80; 95%CI 0.64, 1.00; P = .05 vs RR 0.74; 95%CI, 0.60, 0.92; P = .004, respectively). The graft and patient survivals, chronic rejection, and serum creatinine were similar to the steroid continuing group.

CONCLUSION

Steroid withdrawal can significantly increase the risk of acute rejection episodes, but reduces the incidence of infection to a certain extent. To prophylaxis against serious infection, steroid withdrawal is worth considering using a sufficient immunosuppressive regimen. The key point is to balance the benefit and harm for the individual recipient.

Entity evidence for differentiation between Tia and Tib types of soybean Kunitz trypsin inhibitor: detection of a novel transitional variant type between Tia and Tib in wild soybean (Glycine soja Sieb. & Zucc.)

Soybean Kunit trypsin inhibitor (SKTI) has several polymorphic types. Of these SKTI, there are large differences of nine amino acid substitutions between Tia and Tib. So far no transitional type between them has been found. A novel transitional intermediate variant between Tia and Tib was detected in 11 lines from 720 Japanese wild soybeans (Glycine soja Sieb. & Zucc.). This variant showed identical electrophoretic mobility to Tib in the Davis system polyacrylamide gel electrophoresis (PAGE), but higher electric points than other SKTI proteins (Tia, Tib, Tic) in isoelectric focusing PAGE. The genetic analysis of SKTI in F(2) seeds from a cross between the novel variant type and Tib showed that this variant type is inherited as codominant alleles in a multiple allelic system at an SKTI locus. This variant also showed inhibitory activity to trypsin. We propose the genetic symbol Ti b ( i5) for this novel variant. The sequence analysis of Tib ( i5) revealed that six nucleotides were different between Tib ( i5) and Tia, and the nucleotides of these mutated positions were identical to Tib. This causes substitution of five amino acids at the residue position 62 (Tyr-->Phe), 74 (Ser-->Arg), 114 (Met-->Val), 120 (Leu-->Ile) and 137 (Pro-->Thr). These substitutive amino acids are completely in accord with the amino acids of Tib, showing that Tib ( i5) is an intermediate between Tia and Tib types. Tib ( i5) type is widely distributed throughout seven separate areas from northeast to southwest Japan with a 1.5% frequency of total materials examined. This indicated that Tib ( i5) type did not originate from a recent mutation event, but had spread in wild soybean from ancient times.

Changes in the rate of photosynthesis accompanying the yield increase in wheat cultivars released in the past 50 years

Photosynthetic rates in different development stages were carefully investigated in 18 cultivars of winter wheat released in the period between 1945 and 1995 in the area of Beijing, China. During this period, the recorded grain yield has increased eightfold. However, when those cultivars were planted and managed in the same environment, the difference was reduced to only 36%, indicating that agronomic practices are the most important factors for grain yield. Agronomic features have changed greatly in the past 50 years, through increasing the harvest index (R2 = 0.89, P < 0.05), shortening plant height (R2 = 0.77, P < 0.05) and slightly increasing flag leaf areas (R2 = 0.45, P < 0.05), which is mostly in agreement with many other researchers. In contrast to many reports, however, this study found a genetic increase in the rate of photosynthesis per unit leaf area. From the mid-stem elongation to soft dough stages, the average photosynthetic rates at saturated photosynthetic photon flux density (P(sat)) increased by 44%. In the process, the stomatal conductance (g(s)) also increased by 122%. Grain yield was positively related to the mean values of P(sat) (R2 = 0.61, P < 0.01) and g(s) (R2 = 0.67, P < 0.01) in the six development stages. Our experiment may suggest that increase in grain yield was associated with the elevation of leaf photosynthetic rate and stomatal conductance over the past 50 years.

Effect of inhibitors on the montmorillonite clay-catalyzed formation of RNA: studies on the reaction pathway

The Langmuir adsorption isotherms of the phosphoroimidazolides of adenosine (ImpA) and uridine (ImpU), dA5' ppdA and N6,N6-dimethyladenine binding on montmorillonite are consistent with their forming a monolayer on the clay surface. This suggests the condensation of ImpA and ImpU to oligomers proceeds on the surface of the clay and not in groups of monomers stacked on the clay surfaces. The binding and reactions of ImpU and ImpA on montmorillonite are blocked by N6,N6-dimethyladenine and dA5' ppdA. dA5' ppdA is a better inhibitor of oligomer formation than N6,N6-dimethyladenine because both adenine rings of dA5' ppdA bind to the clay surface and block adjacent catalytic sites. An upper limit of 5-10 x 10(15) catalytic sites on 50 mg of clay was estimated from the binding of ImpU and the inhibition of oligomer formation by dA5' ppdA.

[Phylogenetic analysis of interspecies in genus Glycine through SSR markers]

The genetic diversity among 11 species of genus Glycine (altogether 37 accessions) was evaluated through SSR analysis. The number of alleles in different loci ranges from 6 to 29, averaging 15.9 per locus; alleles of subgenus soja account for 71.5% of those in subgenus Glycine, and the fingerprinting among subgenus Glycine is more divergent than that of subgenus soja. Principal factor analysis shows that the first and the second principal factor can classify genus Glycine into two groups which represent subgenus Glycine and subgenus soja. The results of UPGMA indicate that G. mas, G. soja and G. gracilis in subgenus soja are different species.

[Xenogeneic graft-versus-host disease]

OBJECTIVE

To evaluate the histological characteristics of xenogeneic graft-versus-host disease (GVHD), and to differentiate it from the allogeneic GVHD.

METHODS

The original articles related to the characteristics of xenogeneic GVHD and the relationship between xenogeneic GVHD and allogeneic GVHD were widely reviewed in the past decade.

RESULTS

Xenogeneic GVHD was different from allogeneic GVHD in the speed of development, position and features of pathological changes, due to the incompatibility of common simulative signals, adhesive molecules and difference of antigens. Xenogeneic spleen transplantation could induce xenogeneic GVHD.

CONCLUSION

Xenogeneic GVHD can be used as a model to mimic rejection in xenotransplantation and to evaluate the compatibility of xenotransplantation.

A case-control study of hepatitis B and C virus infection as risk factors for hepatocellular carcinoma in Henan, China

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world and is particularly prevalent in China. China is also a hyperendemic area for hepatitis B virus (HBV) infection. Although a strong association between HBV infection and HCC has been established previously, the role of hepatitis C virus (HCV) infection and the interaction between HBV and HCV in the development of HCC has not been adequately explored. The major objective of this study is to determine the relationship between HBV or HCV infection and HCC by use of case-control study in Henan, China.

METHOD

In all, 152 HCC patients and 115 control patients were collected from four hospitals in Henan, China between January 1994 and October 1995. The demographic characteristics of the two groups were comparable. In further analysis, a 1:1 pair-matched case-control study was performed. Of 152 HCC patients, 113 were randomly selected to be pair-matched by sex and age (+/-5 years) to controls with non-hepatic disease. All the cases and controls were interviewed during hospitalization by two specially trained interviewers using a standard questionnaire. All sera were tested for HBV and HCV markers. Odds ratios (OR) and 95% CI for HCC risk factors were calculated by logistic regression model controlling for possible confounding factors such as sex and age. The multivariate analysis was done on the basis of the univariate analysis.

RESULTS

The results of this study indicated that the prevalence of hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were much higher in HCC patients (63.2% and 11.2% respectively) than in the control patients (5.2%, 3.5%). The difference between two groups was significant (P < 0.05). Risk factor analysis revealed that both HBV and HCV infection were important factors for HCC in Henan, China and HBV appeared to have a key role in the development of HCC. Odds ratios of HBsAg and HBV infection were 28.82 (95% CI: 11.18-78.78) and 31.22 (95% CI: 13.86-72.15), respectively. Moreover, the risk of developing HCC increased significantly and showed an additive effect when both viral markers of HBV and HCV infection were considered (OR = 42.85). Results from the 1:1 pair-matched case-control study also showed that HBV infection was an important risk factor for HCC, which was consistent with the results from the group-matched case-control study.

CONCLUSION

This is the first reported case-control study of HCC in Henan, China. This study provides further evidence that chronic HBV infection is strongly associated with the development of HCC among this population. Our results have demonstrated that HCV and HBV infection are independent and probably additive risk factors for HCC.

[Study on the epidemiology of HP infection among 464 school staff in Henan Province]

An epidemiological study of Helicobacter pylori (HP) infection among 464 school staff was carried out by detecting sera urease antibody. The result showed that HP infection rate was 42.03% and increased with age. It was higher among persons with upper gastrointestinal symptoms and with gastric disease than without. The rate of HP infection tended to relate to factors as educational level, income, alcohol consumption but did not reach significant level statistically. HP infection did not seem to be related to gender, members in a family and smoking.

[A case-control study on electrocardiographic abnormalities and hypertension in long-term survivors of cerebrovascular disease]

In order to assess the ECG change and the effect of hypertension in relation to the occurrence and outcome of the cerebrovascular disease (CVD) in its advanced stage. 78 such patients together with the same number of control subjects were selected randomly, studied and compared in a neuroepidemiological survey. This study showed that ECG abnormality was associated with the female patients with CVD (P less than 0.05). The presence of unconsciousness during the acute stage of CVD was related to subsequent ECG abnormality (P less than 0.05) and to late severe disability (P less than 0.05). In the late stage of CVD hypertension was still a risk factor for both sexes (P less than 0.01), and there were more patients above the age of 65 complicated by hypertension than those below the age of 65 (P less than 0.05). Hypertension had a positive relationship with the degree of disabilities in patients with CVD. It was emphasized that cardiac disorders and hypertension should be properly taken care of even though the CVD had been in its later stage.

Monoamine metabolites in cerebrospinal fluid during and after acute cerebral ischemia

In order to understand the role of monoamines in cerebral ischemia, 3-methoxy-4-hydroxyphenylglycol(MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid(HVA), the three major unconjugated monoamine metabolites in cerebrospinal fluid (CSF), of 33 patients and 18 controls were measured with high performance liquid chromatography. Results showed all three metabolites were raised in patients with severe ischemia, but only MHPG and 5-HIAA were elevated significantly, MHPG changes more quickly and regularly as a consequence of cerebral ischemia than the two others. A positive correlation between any pair of metabolites was found in controls and in patients in the first week after stroke, but not at the end of the second week. Computer assisted multivariate analysis indicated 5-HIAA and MHPG correlated more closely with the state of illness in the acute stage, whereas HVA correlated the least. Possible explanations for the changes of CSF levels of amine metabolites are discussed.

Monoamine metabolites in cerebrospinal fluid during acute cerebral ischemia

To clarify the rule of monoamine in cerebral ischemia, 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid (CSF) of 33 patients and 18 controls were measured with high performance liquid chromatography. Results showed all the three metabolites increased in patients with severe ischemia but only MHPG and 5-HIAA increased significantly. MHPG changed more quickly and regularly in cerebral ischemia than the other two. A positive correlation between any couple of the metabolites was found in both the controls and patients in the first week after stroke, but it was disturbed at the end of the second week. Computer-assisted multivariate analysis indicated that 5-HIAA and MHPG are more closely related to the state of illness in the acute stage while HVA the least. Possible explanations for the changes of CSF levels of amine metabolites were discussed.

Serum cholesterol, its lipoprotein fractions among survivors of cerebrovascular disease. A case-control study

A case-control study was conducted in 1983 on 210 cerebrovascular disease (CVD) patients identified from a retrospective cross-sectional door-to-door survey of four cities in the People's Republic of China. One hundred and eleven male (mean age 63.8 +/- 8.9 years) and 99 female (mean age 63.5 +/- 11.1 years) CVD survivors and controls matched for sex, age, race and area were selected. Total serum cholesterol, high-density lipoprotein and low-density lipoprotein cholesterol were measured to see if there were differences between lipids in survivors of CVD and their matched controls. There was a higher level of total cholesterol in cerebral thrombotic patients (n = 114) and a lower level of total cholesterol and high-density lipoprotein cholesterol in cerebral hemorrhagic patients (n = 35) than in controls, although the results were not statistically significant. The only higher level of total serum cholesterol that might be important was in the group of male thrombotic patients of age greater than 70 years (n = 22; nominal p value less than 0.05). The implication of this finding needs further clarification.