Improvement of the estimation of the infiltration function in surface irrigation systems

Surface irrigation systems are widely used on the North China Plain. The design of surface irrigation systems can be improved by developing simulation models including the advanced trajectory, recession trajectory, and infiltration time. Therefore, the objectives of this study were as follows: (1) to evaluate different models to simulate the advanced and recession trajectories, (2) to propose a new method that reduces the required observation data for estimating the infiltration time, and (3) to evaluate the accuracy of the proposed infiltration function based on the modified infiltration time function. Field experiments were conducted. The results indicated that the power function can represent the advanced and recession trajectories well. A modified function that describes the infiltration time has a high correlation and accuracy with the measured data and can be used to estimate the infiltration time. The proposed infiltration function based on the modified infiltration time function is accurate and can be used to estimate the infiltration function.

A reduced latency regional gap-filling method for SMAP using random forest regression

The soil moisture active/passive (SMAP) mission represents a significant advance in measuring soil moisture from satellites. However, its large spatial-temporal data gaps limit the use of its values in near-real-time (NRT) applications. Considering this, the study uses NRT operational metadata (precipitation and skin temperature), together with some surface parameterization information, to feed into a random forest model to retrieve the missing values of the SMAP L3 soil moisture product. This practice was tested in filling the missing points for both SMAP descending (6:00 AM) and ascending orbits (6:00 PM) in a crop-dominated area from 2015 to 2019. The trained models with optimized hyper-parameters show the goodness of fit (R² ≥ 0.86), and their resulting gap-filled estimates were compared against a range of competing products with in situ and triple collocation validation. This gap-filling scheme driven by low-latency data sources is first attempted to enhance NRT spatiotemporal support for SMAP L3 soil moisture.

An improved approach to estimating the infiltration characteristics in surface irrigation systems

The most common methods for estimating the infiltration function are measurements through a double-ring infiltrometer (DRI) and empirical models. Infiltration data always exhibit different kinds of scatter, which affect the accuracy of the estimated infiltration function. This study presents a new methodology to calibrate the infiltration function. The suggested approach is based on combining the DRI method with the changes in the measured soil water content. Furrow irrigation experiments were conducted to estimate the infiltration function using different methods and to investigate the effect of data scatter on the reliability of the estimated infiltration function. Furrow elevations were observed, and for each irrigation event advance times, recession times, and inflow rates were observed. The infiltration depths were measured as a function of the change in the soil water content before and after irrigation event. Infiltration parameters were estimated using DRI treatment, empirical model (Kostiakov model), and suggested approach. Measured and simulated infiltration depths using the described methods were compared. The results show that the infiltration depths estimated using a DRI were lower than the observed infiltration depths, while the infiltration depths estimated using the empirical model were higher than the observed infiltration depths. The results indicate that the infiltration function estimated using the recommended approach was more accurate and reasonable than the infiltration function estimated using the DRI, and empirical (Kostiakov model) methods. In addition, the proposed approach can reduce the required measurements during the irrigation event, and can also reduce the potential scatter in the estimated infiltration function that results from soil variability and measurement errors.

High-order exceptional points in optomechanics

We study mechanical cooling in systems of coupled passive (lossy) and active (with gain) optical resonators. We find that for a driving laser which is red-detuned with respect to the cavity frequency, the supermode structure of the system is radically changed, featuring the emergence of genuine high-order exceptional points. This in turn leads to giant enhancement of both the mechanical damping and the spring stiffness, facilitating low-power mechanical cooling in the vicinity of gain-loss balance. This opens up new avenues of steering micromechanical devices with exceptional points beyond the lowest-order two.

A Modified Soil Moisture Model for Two-Layer Soil

There can be marked variations in soil hydraulic properties in a soil vertical profile from the soil surface to the base of the root zone. Many existing two-layer soil moisture (TLSM) models cannot well describe typical stratified soil profiles. A modified TLSM model is presented in this study. The modified model results and those from two existing models are compared with field observations. The modified TLSM model had the best agreement with the field observations. In both the surface layer and the root zone layer, the root mean square errors of soil moisture estimated by the modified model were smaller than those for the other models. The parameters in the modified TLSM model are relatively easy to determine. The modified TLSM model offers clear advantages over current TLSM models.

Black holes in higher derivative gravity

Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this Letter we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics.

Mediation by calcium/calmodulin-dependent protein kinase II of suppression of GABA(A) receptors by NMDA

Using nystatin-perforated whole-cell recording configuration, the modulatory effect of N-methyl-D-aspartate (NMDA) on gamma-aminobutyric acid (GABA)-activated whole-cell currents was investigated in neurons freshly dissociated from the rat sacral dorsal commissural nucleus (SDCN). The results showed that: (i) NMDA suppressed GABA-and muscimol (Mus)-activated currents (I(gaba) and I(Mus)), respectively in the Mg(2+)-free external solution containing 1 mumol/L glycine at a holding potential (V ( H )) of -40 mV in SDCN neurons. The selective NMDA receptor antagonist, D-2-amino-5-phosphonovaleric acid (APV, 100 gammamol/L), inhibited the NMDA-evoked currents and blocked the NMDA-induced suppression of I(gaba); (ii) when the neurons were incubated in a Ca(2+)-free bath or pre-loaded with a membrane-permeable Ca(2+) chelator, BAPTA AM (10 mumol/L), the inhibitory effect of NMDA on I(GAba) disappeared. Cd(2+) (10 mumol/L) or La(3+) (30 mumol/L), the non-selective blockers of voltage-dependent calcium channels, did not affect the suppression of I(gaba) by NMDA application; (iii) the suppression of I(GAba) by NMDA was inhibited by KN-62, a calcium/calmodulin-dependent protein kinase II (CaMKII) inhibitor. These results indicated that the inhibition of GABA response by NMDA is Ca(2+)-dependent and CaMKII is involved in the process of the Ca(2+)-dependent inhibition.

Critical gravity in four dimensions

We study four-dimensional gravity theories that are rendered renormalizable by the inclusion of curvature-squared terms to the usual Einstein action with a cosmological constant. By choosing the parameters appropriately, the massive scalar mode can be eliminated and the massive spin-2 mode can become massless. This "critical" theory may be viewed as a four-dimensional analogue of chiral topologically massive gravity, or of critical "new massive gravity" with a cosmological constant, in three dimensions. We find that the on-shell energy for the remaining massless gravitons vanishes. There are also logarithmic spin-2 modes, which have positive energy. The mass and entropy of standard Schwarzschild-type black holes vanish. The critical theory might provide a consistent toy model for quantum gravity in four dimensions.

Hypoglycemic effect of the total flavonoid fraction from folium Eriobotryae

The antidiabetic effect of the total flavonoids fraction from leaves of Eriobotrya japonica (EJF) was evaluated through normal and streptozotocin-induced diabetic mice with graded oral doses of 150, 300, 450 mg/kg for 7 days or 14 days. The result showed that the dose of 300 mg/kg and 450 mg/kg resulted significant hypoglycemic effect on normal mice, the dose of 300 mg/kg induced significant decrease in plasma glucose concentration (PGC), glycosylated serum protein (GSP), total cholesterol (TC) and triglyceride (TG), and significant increase in superoxide dismutase (SOD) activity and serum insulin level in streptozotocin-diabetic mice. These results suggested that EJF has hypoglycemic potential.

Solutions to horava gravity

Recently Horava proposed a nonrelativistic renormalizable theory of gravitation, which reduces to Einstein's general relativity at large distances, and that may provide a candidate for a UV completion of Einstein's theory. In this Letter, we derive the full set of equations of motion, and then we obtain spherically symmetric solutions and discuss their properties. We also obtain solutions for the Friedmann-Lemaître-Robertson-Walker cosmological metric.

Hypoglycemic and hypolipidemic effects of the total triterpene acid fraction from Folium Eriobotryae

For seeking the good natural material to develop new agent to treat diabetes, the total triterpene acid (TTA) fraction extracted from Folium Eriobotryae [leaves of Eriobotrya japonica (Thunb.) Lindl.] was evaluated for its hypoglycemic and hypolipidemic potential through normal, alloxan and streptozotocin-induced diabetic mice administered with graded oral doses (100, 200, 300 mg/(kg day)) for 7 or 14 days. The results showed that a dose of 300 mg/kg of TTA is the most effective dose to cause significant (p<0.01) hypoglycemic and/or hypolipidemic effects on normal, alloxan and streptozotocin-induced diabetic mice. This dose also significantly (p<0.01) lowered the glycosylated serum protein (GSP), total cholesterol (TC) and triglyceride (TG) level in severely diabetic mice. Furthermore, TTA increased the superoxide dismutase activity (SOD) and the serum insulin level of diabetic mice. These evidences indicated that the total triperpene acid fraction from Folium Eriobotryae has a high anti-diabetic potential along with a good hypolipidemic profile.

General nonextremal rotating black holes in minimal five-dimensional gauged supergravity

We construct the general solution for nonextremal charged rotating black holes in five-dimensional minimal gauged supergravity. They are characterized by four nontrivial parameters: namely, the mass, the charge, and the two independent rotation parameters. The metrics in general describe regular rotating black holes, providing the parameters lie in appropriate ranges so that naked singularities and closed timelike curves (CTCs) are avoided. We calculate the conserved energy, angular momenta, and charge for the solutions, and show how supersymmetric solutions arise in a Bogomol'nyi-Prasad-Sommerfield limit. These have naked CTCs in general, but for special choices of the parameters we obtain new regular supersymmetric black holes or smooth topological solitons.

New Einstein-Sasaki spaces in five and higher dimensions

We obtain infinite classes of new Einstein-Sasaki metrics on complete and nonsingular manifolds. They arise, after Euclideanization, from BPS limits of the rotating Kerr-de Sitter black hole metrics. The new Einstein-Sasaki spaces L(p,q,r) in five dimensions have cohomogeneity 2 and U(1) x U(1) x U(1) isometry group. They are topologically S(2) x S(3). Their AdS/CFT duals describe quiver theories on the four-dimensional boundary of AdS(5). We also obtain new Einstein-Sasaki spaces of cohomogeneity n in all odd dimensions D = 2n + 1 > or = 5, with U(1)(n + 1) isometry.

Brane worlds in collision

We obtain an exact solution of the supergravity equations of motion in which the four-dimensional observed Universe is one of a number of colliding D3 branes in a Calabi-Yau background. The collision results in the ten-dimensional spacetime splitting into disconnected regions, bounded by curvature singularities. However, near the D3 branes the metric remains static during and after the collision. We also obtain a general class of solutions representing p-brane collisions in arbitrary dimensions, including one in which the universe ends with the mutual annihilation of a positive-tension and a negative-tension 3 brane.

Rotating black holes in higher dimensions with a cosmological constant

We present the metric for a rotating black hole with a cosmological constant and with arbitrary angular momenta in all higher dimensions. The metric is given in both Kerr-Schild and the Boyer-Lindquist form. In the Euclidean-signature case, we also obtain smooth compact Einstein spaces on associated S(D-2) bundles over S2, infinitely many for each odd D>/=5. Applications to string theory and M-theory are indicated.

M-theory conifolds

Seven manifolds of G2 holonomy provide a bridge between M-theory and string theory, via Kaluza-Klein reduction to Calabi-Yau six manifolds. We find first-order equations for a new family of G2 metrics D7, with S3 x S3 principal orbits. These are related at weak string coupling to the resolved conifold, paralleling earlier examples B7 that are related to the deformed conifold, allowing a deeper study of topology change and mirror symmetry in M-theory. The D7 metrics' nontrivial parameter characterizes the squashing of an S3 bolt, which limits to S2 at weak coupling. In general the D7 metrics are asymptotically locally conical, with a nowhere-singular circle action.

Potentiation of docetaxel antitumor activity by batimastat against mouse forestomach carcinoma

OBJECTIVE

To improve the treatment of tumors, we studied the combined effects of docetaxel and batimastat (BB-94) on mouse forestomach carcinoma (MFC), and compared them with doxorubicin.

METHODS AND RESULTS

In vitro, growth curve analysis, MTT assay and clonogenic assay used to determine the cytotoxic effect of docetaxel or/and BB-94 on MFC cell showed that docetaxel but not BB-94 had a significant cytotoxicity, and the effect of docetaxel wasn't enhanced by BB-94. In early stage MFC tumor model, obvious antitumor effect of docetaxel or doxorubicin given i.v. at maximum tolerated dose (MTD, docetaxel: 20 mg/kg; doxorubicin: 6 mg/kg) every 4 days for 3 injections (q4d x 3), even that of BB-94 (30 mg/kg i. p. qd x 20) was observed. Tumor growth inhibition was greater for docetaxel-batimastat (96.0%) than for doxorubicin-batimastat (88.0%), docetaxel (89.0%), doxorubicin (68.0%) and BB-94 (33.0%), and the effect of docetaxel could be potentiated by BB-94. Docetaxel also showed activity against advanced stage MFC tumor in dose-dependent manner, and was more effective at MTD than doxorubicin with 4/5 regressions, 46.5 days tumor growth delay and 2.8log(10) tumor cell kill.

CONCLUSION

Our results suggest that in the MFC model with dose and schedule used, docetaxel is an effective cytotoxic new drug against MFC tumor and BB-94 enchances the antitumor activity of docetaxel.

[An analysis on the forearm bone mass density of rural female and the environmental risk factors]

The distribution of distal and proximal forearm bone mass densities (BMD) with age was discribed and the environmental risk factors of rural female analyzed. A group of 1432 rural female aged 15 and over were sellected. Their demographic characteristics, living and eating habit were obtained by standardized questionnaire. The distal and proximal forearm bone mass density were measured by peripheral dual-energy X ray absorptionmetry (pDEXA). The results showed that the distal and proximal forearm BMDs were increased with age before age 25 and 30 respectively, and reached the peak value at age 30-35. The distal forearm bone density decreased significantly at age 40 while the proximal forearm BMD decreased at age 45. Bone loss rate of the two bone sites was increased significantly at age 50 and reached the peak value at age 55-60. Only the the density of proximal forearm bone, and the year of menopause was the main cause of low bone density. Body weight was the positive factor for bone density at age less than 60. Height only positively affected the proximal forearm bone of those at age 30-45. More ever, drinking tea, parity and educational status may affect distal forearm bone in certain age group while parity, educational status, occupation and marital status were possible risk factors of proximal forearm BMD. It is concluded that environmental risk factors of BMD varied with bone site and age. The prevention of low BMD must rely on subject's age and bone site. The surveillance of low bone density must put the emphasis on spony bone.

Potentiation of docetaxel antitumor activity by batimastat against mouse forestomach carcinoma

Docetaxel is a chemical compound belonging to the taxoid class of anticancer agents. Batimastat (BB-94) is the first matrix metalloproteinase inhibitor entering clinical trials. To improve the treatment of tumors, we studied the combined effects of docetaxel and batimastat on mouse forestomach carcinoma (MFC), and compared them with doxorubicin. In vitro growth curve analysis, MTT assay, and clonogenic assay were used to determine the cytotoxic effect of docetaxel or/and BB-94 on MFC. They showed that docetaxel, but not BB-94, had a significant cytotoxicity and that the effect of docetaxel was not enhanced by BB-94. In an early stage MFC tumor model, an obvious antitumor effect of docetaxel or doxorubicin given iv at maximum tolerated dose (MTD) was observed. Tumor growth inhibition was greater for docetaxel + BB-94 (96.0%) than for doxorubicin + BB-94 (88.0%), docetaxel (89.0%), doxorubicin (68.0%), and BB-94 (33.0%). Docetaxel showed activity against advanced stage MFC tumor in a dose-dependent manner and was more effective at MTD than doxorubicin, with 4/5 regression, 46.5 days tumor growth delay, and 2.8 log10 tumor-cell kill. Our results suggest that docetaxel is an effective new cytotoxic drug against MFC tumor and that BB-94 enhances the antitumor activity of docetaxel in the dose and schedule used.

[Posterior atlantoaxial facet screw fixation in rheumatoid arthritis]

OBJECTIVE

To clarify the characteristics of the clinicopathological factors in cases of atlantoaxial instability due to rheumatoid and to introduce a new method for the treatment of this disease.

METHODS

Fifteen patients with atlantoaxial instability due to rheumatoid were treated with posterior facet screws to obtain immediate rigid fixation of C(1 - 2). In this series of patients, screw fixation was augmented with an interspinous C(1 - 2) strut graft which was wired in place to provide three-point stabilization and to facilitate bone fusion.

RESULTS

In each patient fixation was satisfactory, and C(1 - 2) alignment and stability were restored without complication due to instrumentation. All patients showed osseous union (a mean follow-up period of 10 months; range 6 - 14 months).

CONCLUSION

Posterior atlantoaxial facet screw fixation provides immediate three-dimension rigid fixation of C(1 - 2) that is biomechanically superior to wiring or other fixation.

Cytotoxic effects of 5-fluorocytosine on melanoma cells transduced with cytosine deaminase gene

To investigate the cytotoxic effects of 5-fluorocytosine on melanoma cells genetically modified with cytosine deaminase gene, the gene was transduced into the tumor cells with the retroviral method. The cytotoxicity effects of 5-fluorocytosine on the tumor cells were measured with the MTT assay and clonogenic assay. It was found that the prodrug 5-fluorocytosine had significant cytotoxic effects on melanoma cells transduced with cytosine deaminase in vitro. The IC50 value of 5-fluorocytosine on transgenic and nontransgenic melanoma cells was 572 microg/mL(-1) and 3870 microg/mL(-1), respectively. Our experiment demonstrated the potential value of the cytosine deaminase gene/5-fluorocytosine system in the treatment of melanoma.

[The identification and cloning of human ubiquitin binding enzyme cDNA]

OBJECTIVE

To identify and clone the gene encoding human ubiquitin binding enzyme and study its expression spectrum.

METHODS

According to the sequence of human EST, which is highly homologous to the mouse ubiquitin conjugating enzyme (E2), primers used for library screening were synthesized to screen the human fetal brain cDNA library. The gene was analyzed by making use of bioinformatics and its expression spectrum was studied by using multiple-tissue Northern blot.

RESULTS

Two cDNA clones encoding human ubiquitin conjugating enzyme were isolated and identified. Both containing the ubiquitin conjugating domain, they were 88% identical in amino acid sequences and found to be isoforms of each other with only an exon excised from the short sequence. They belonged to a highly conserved, and widely expressed E2 enzyme family. Northern blot showed that they were expressed exclusively in heart, placenta, and pancreas while no transcripts could be detected in brain, lung, liver, skeletal muscle, or kidney.

CONCLUSIONS

The gene encoding human ubiquitin binding enzyme is expressed under both temporal and spatial control. As a key enzyme in the degradation of proteins, ubiquitin conjugating enzymes play a central role in the expression regulation on the level of post-translation.

[Clinical analysis of 13 infected total knee replacements]

OBJECTIVE

To investigate the cause, treatment and its result of infected total knee replacements (TKRs).

METHODS

Between 1987 and 1999, 13 infected TKRs in 13 patients were treated with surgical debridement and one-stage or two-stage reimplantation. The preoperative average ROM of knees was 55 degrees and the average Hospital for Special Surgery (HSS) knee score was 36.5 points. Clinical results were evaluated after average follow-up for 3 years and 5 months. We analyzed the factors for TKR infection.

RESULTS

No recurrent infection was noted, and pain was significantly alleviated in all patients. The average ROM of knees was 85 degrees and the average HSS knee score was 73.5 points.

CONCLUSIONS

The high risk factors for TKR infection are rheumatoid arthritis, steroid administration, associated diabetes mellitus, hinged prosthesis and previous knee surgery. Early surgical debridement with intravenous antibiotics is necessary as soon as deep infection is detected. Two-stage reimplantation is more effective in eradicating deep infection than single debridement or one-stage reimplantation.

[Risk factors for nosocomial infections after total knee replacement]

OBJECTIVE

To investigate prevalence and risk factors of nosocomial infections in patients with total knee replacement.

METHODS

From August 1993 to October 1998, total knee replacement was performed on 363 patients (503 knees). The difference of nosocomial infection rates was statistically analyzed in comparison with different age, primary disease, and associated disease groups.

RESULTS

No statistically significant difference was observed in nosocomial infection when compared rheumatoid arthritis with osteoarthritis, bilateral total knee replacement (TKR) with unilateral TKR and different ages. However, the higher nosocomial infection rate was related to the following factors: revision surgery, steroid administration and diabetes urinary infection. 28 female patients demonstrated higher urinary infection rate than that in other systems.

CONCLUSIONS

Nosocomial infection rate of TKR in rheumatoid cases is related to steroid administration, accompanying diabetes mellitus, previous knee surgery, aged women and retention of urinary catheter. It is feasible to prevent nosocomial infection by controlling the above-mentioned risk factors.

Engineering human interferon alpha1c/86D with phage display technology

Human interferon-alpha1c/86D (IFNalpha1c/86D) was functionally displayed on the surface of the filamentous bacteriophage using a phagemid vector system (pCANTAB5E). The key amino acid residues involved in the receptor binding were further defined with phage displayed 6-mer peptide library and two neutralizing antibodies against linear epitopes on the IFN-alpha1b, indicating that residues 30, 33, 34, (AB-loop) and residues 124, 126, 127 (D helix, DE-loop) were more critical than the adjacent residues for recognition of receptor. In addition, a cassette mutagenesis library was generated by fully randomizing the sequence of the four positions 29, 31, 32 and 35 in AB-loop, and used to select phage-IFN variants with WISH-based panning method. Three phage-IFN variants were isolated to possess more antiviral activity in the range of 4-16-fold than parental phage-IFN after IPTG-induced soluble expression. The results suggest that phage displayed phage-IFN alpha1c/86D variants with increased specific activity might be obtained after purification procedures.

Tunable output power varying with the splitting ratio of a coupler from a fiber ring semiconductor laser

The tunable output power characteristics of a fiber ring semiconductor laser have been studied by use of rate equations. An expression for the tunable output power is deduced. The analysis confirms that there is an optimum coupler splitting ratio to trade off between wavelength tuning width and output power.

NodD binds to target DNA in isologous octamer

NodD, the major regulatory protein of nodulation, was partially purified from Rhizobium leguminosarum 8401(pIJ1518), and its binding sequences within nodF promoter of R. l. bv. viciae were determined by DNase I footprinting. A series of techniques based on gel retardation were used to analyze the NodD-target DNA interaction, showing that NodD binds to target DNA in isologous octamer.

[Detection of type 6 human herpesvirus (HHV-6) specific DNA sequence in lymphoma tissues by PCR]

OBJECTIVE

To study the relationship between human herpesvirus-6 (HHV-6) and lymphoma in China.

METHODS

The specimens of paraffin-embedded lymphoma tissue, leukemia cell lines and normal blood donor peripheral blood lymphocytes(PBL) were examined for the presence of HHV-6 DNA sequence by polymerase chain reaction (PCR).

RESULTS

Of the 52 cases lymphoma studied, HHV-6 DNA sequence was detected in 21 cases; of 43 normal PBL, HHV-6 DNA sequence was detected in 8 cases. The difference was statistically significant (P < 0.05). HHV-6 DNA sequence was also present in two leukemia cell lines.

CONCLUSION

The results suggest that HHV-6 may be related to lymphoma in China.

Migration and gap junctional intercellular communication determine the metastatic phenotype of human tumor cell lines

Gap junctional intercellular communication (GJIC) as well as cell migration play an essential role in the metastatic cascade of human tumors. We show a dependence of metastatogenic phenotypes of human tumor cells (cell lines T 24, SCC-25, MDA-MB-361 and SK-BR-3) from the GJIC and the migration activity. The GJIC was studied by microinjection of the fluorescent dye Lucifer Yellow (LY) and cell migration was studied by investigating the locomotion of the tumor cells in 3-dimensional collagen matrices. Diminished GJIC seems to be more influential for the metastatic phenotype than modulation of the locomotory behavior of the tumor cells.

Locomotory phenotypes of human tumor cell lines and T lymphocytes in a three-dimensional collagen lattice

Active cellular locomotion is a feature of such diverse cell types as lymphocytes and cancer cells. The locomotory phenotype of a cell should ultimately reflect the biochemical basis of different migratory strategies. We investigated the locomotory behavior of five epithelial cell lines and one non-epithelial human cell-line as well as human CD4+ T lymphocytes in a three-dimensional collagen type I matrix using time-lapse video microscopy and computer assisted cell-tracking. Migration velocity was up to 70 times lower in tumor cells (0.1-0.3 microm/min) as compared to T lymphocytes (7-7.5 microm/min), whereas the percentage of spontaneously active cells was up to twice as high in tumor cells (80-90%) in comparison to T lymphocytes (54%). Persistence, i.e. the degree of roaming, varied appreciably between the different cell types. In conclusion, velocity and persistence may describe distinct migration strategies in different cell types, i.e. discerning T cell migration from tumor cell invasion.

[The study on analgesic effect of local-release delivery system--Huangjiabang]

Laboratory investigation was made on analgesic effect of local release delivery system, Huangjiabang, which mainly includes Chinese medical herbs. Through the application of twisting-body and thermal-plate experiments on white rats. The result showed that the pain threshold was markedly elevated (P < 0.05, P < 0.001) after the rats were fed with Huangjiabang 125 mg/kg or 250 mg/kg body weight, and the number of twisting body's animals significantly decreased (P < 0.001). The analgestic mechanism of Huangjiabang delivery system relates to its effect of invigorating the circulation of blood and accelerating the stasis assimilation, remitting the inflammation.

[Environmental pollution, human exposure and its health effect of sodium pentachlorophenate in schistosomiasis prevalent area]

Sodium pentachlorophenate (Na-PCP) has been used in China for years as an molluscacide to kill oncomelania, which is an intermediate host of Schistosome. To evaluate the effects of its long-term successive usage on environment, human exposure and health, studies were carried out in Sichuan, Jiangxi, Jiangsu and Fujian provinces, with a time gap of more than one month between sample collection and last spray of Na-PCP. Results indicated that PCP contents in surface water, soil, sediment, animals and plants were significantly higher in studied areas than in control areas. The daily intake and the content in urine of PCP were also sigificantify higher in studied areas. But, there was no difference on physical and biochemical examinations except that a 22%-28% decrease of blood cholinesterase activity was found in studied areas. The health effect of impurities in Na-PCP, dioxins and furans, was assessed and discussed.

Ankylosing spondylitis and heterogeneity of HLA-B27 in Chinese

OBJECTIVE

To examine the relationship between ankylosing spondylitis and heterogeneity of HLA-B27 in Chinese.

PATIENTS AND METHODS

We subtyped HLA-B27 in 76 patients with ankylosing spondylitis and 1 200 healthy Chinese of Han nationality. Polymerase chain reaction was designed to amplify specific regions of class I (exon 2 and 3). Amplified sequences were tested with eight sequence-specific oligonucleotides to distinguish all HLA-B27 subtypes.

RESULTS

The HLA-B27 was closely related to ankylosing spondylitis and at least four subtypes presented in Chinese patients. B2704 was the most common subtype, occurring in 54.8% and 50.85% respectively in HLA-B27 positive ankylosing spondylitis patients and healthy controls. The main HLA-B27 subtypes in the HLA-B27 positive patients distributed in similar proportion to those of HLA-B27 positive healthy controls (P < 0.1).

CONCLUSIONS

The prevalences of various subtypes of HLA-B27 vary in different races. HLA-B2704 is the main subtype in Chinese Han nationality. The HLA-B27 specific residues that are shared by the subtypes might be involved in the pathogenesis of ankylosing spondylitis.

Maternal determinants of birth weight: a population-based sample from Qingdao, China

This analysis examines the relationship between maternal determinants and birth weight in a population-based birth cohort of 5,284 mothers with singleton births of 28 completed gestational weeks in Qingdao, China, in 1992. Multiple linear regression models suggest that the length of the menstrual cycle, age at menarche, maternal weight, maternal height, parity, and number of antenatal visits had independent effects on birth weight after controlling for gestational age and sex of infant. The estimated difference in mean birth weight for each year after menarche was 11.7 g (95 per cent CI 4.6-18.8), and for each day of the menstrual cycle was 4.0 g (95 per cent CI, 2.1-6.0), after controlling for gestational age, sex of infant, maternal height, maternal weight, parity and the number of antenatal visits. No substantial differences in determinants of birth weight were found between the sexes. Maternal age, education, and occupation failed to reveal any significant association with birth weight. In sum, those women who reached menarche younger and had a relatively short menstrual cycle had a heavier baby on average, and the determinants of birth weight did not differ between male and female in the cohort.