Role of extracellular exopolymers in biological phosphorus removal

Three sequencing batch reactors (SBRs) supplied with different carbon sources were investigated. The system supplied with glucose gained the best enhanced biological phosphorus removal (EBPR), although all of them were seeded from the same sludge. With the measurement of poly-beta-hydroxyalkanoate (PHA) concentration, phosphorus content in sludge and extracellular exopolymers (EPs) with scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS), it was found that the biosorption effect of EPs played an important role in phosphorus removal and that the amount of PHA at the end of anaerobic phase was not the only key factor to determine the following phosphorus removal efficiency.

Crystal structure of 2,3-bis(2-cyanoethylthio)-6,7-vinylenedithiotetrathiafulvalene, C14H10N2S8

C14H10N2S8, triclinic, P1̅ (no. 2), a = 7.753(2) Å, b = 11.403(3) Å, c = 12.371(5) Å, α = 64.10(2)°, β = 84.62(2)°, γ = 77.34(2)°, V = 959.9 Å3, Z = 2, Rgt(F) = 0.061, wRref(F2) = 0.168, T = 293 K.

Crystal structure of tricalcium tantalum trigallium disilicon oxide, Ca3TaGa3Si2O14

Ca3Ga3O14Si2Ta, trigonal, P321 (No. 150), a = 8.1081(4) Å, c = 4.9850(4) Å, V = 283.8 Å3, Z = 1, Rgt(F) = 0.025, wRref(F2) = 0.064, T = 293 K.

Crystal structure of 4,5-(ethoxyethylenedithio)-1,3-dithiole-2-thione, C7H8OS5

C7H8OS5, monoclinic, P121/c1 (No. 14), a = 8.3699(7) Å, b = 17.573(2) Å, c = 7.5305(7) Å, β = 103.584(7)°, V = 1076.6 Å3, Z=4, Rgt(F) = 0.033, wRref(F2) = 0.082, T = 293 K.

Crystal structure of tetra-n-butylammonium (1,3-dithiol-2-thione-4,5-dithiolato)-( diethyldithiocarbamato-S,S')-nickelate(II), (C16H36N)(C8H10NNiS7)

C24H46N2NiS7, monoclinic, C1c1 (No. 9), a = 8.846(2) Å, b = 24.702(6) Å, c = 15.392(3) Å, β = 95.12(1)°, V = 3349.9Å3, Z = 4, Rgt(F) = 0.059, wRref(F2) = 0.166, T = 293 K.

Depletion effect on partial organization of atactic polymer chain segments in microcells

Glass transition for atactic poly(methyl methacrylate) (a-PMMA) prepared in nano-cells by microemulsion polymerization was measured at a faster heating rate after slow cooling of the sample from a temperature above Tg. An additional enthalpy relaxation and glass transition were observed at higher temperatures for the a-PMMA sample due to the partial organization of the chain segments which occurred during microemulsion polymerization. The re-precipitated a-PMMA did not show any self-organization under the same thermal conditions, although there are no changes in molecular weight or tacticity of the polymer chains. A depletion-interaction phenomenon was understood to provide entropic force for the self-organization of polymer chains inside the walls of the microemulsion cells.

Fluorescence detection in capillary arrays based on galvanometer step scanning

A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluoresceins is 3 x 10(-11) M (S/N = 3) for 5 mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

Rubbing-induced molecular reorientation on an alignment surface of an aromatic polyimide containing cyanobiphenyl side chains

Surface lamellar decoration (SLD), surface enhanced Raman scattering (SERS) and optical second harmonic generation (SHG) experiments have been utilized to study the molecular orientation and conformation changes at a rubbed polyimide alignment-layer surface. This aromatic polyimide containing pendent cyanobiphenyl mesogens was synthesized via a polycondensation of 2,2'-bis(3,4-dicarboxy-phenyl)hexafluoropropane dianhydride (6FDA) with bis[omega-[4-(4-cyanophenyl)phenoxy]hexyl] 4,4'-diamino-2,2'-biphenyldicarboxylate (nCBBP, n = 6), abbreviated as 6FDA--6CBBP. Uniform alignment layers, possessing high pretilt angles ranging from 39 degrees to 43 degrees, have been achieved after mechanical rubbing of the polyimide thin film surface at room temperature and subsequent annealing. This is the first time that high pretilt angles have been detected to possess a negative angle (-theta(c)) with respect to the rubbing direction (i.e., opposite to the rubbing direction), considerably different from the conventional pretilt angle (theta(c)) observed along the rubbing direction. This observation is confirmed using magnetic null and SHG methods. Combined polyethylene (PE) SLD and atomic force microscopy experiments reveal that the azimuthal orientation distribution of the long axis of the edge-on PE lamellar crystals is oriented normal to the rubbing direction, indicating that the PE chains are aligned parallel to the rubbing direction. This SLD technique probes the anisotropic surface orientation of the outermost molecules of the rubbed polyimide layer. The SERS results show that prior to rubbing the surface, both the pendent cyanobiphenyls in the side chains and backbones possess nearly planar chain conformations at the polyimide surface. Mechanical rubbing causes not only tilting of the backbone moieties, such as imide-phenylene structure, but also significant conformational rearrangements of the pendent side chains at the surfaces. The molecular mechanism of this unusual alignment is due to the fact that the pendent cyanobiphenyls forms a uniformly tilted conformation on the rubbed surface, and the polar cyano groups point down toward the layer surface deduced from SHG phase measurements. This conformational rearrangement of the side chains results in the formation of fold-like bent structures on the surface, which directly leads to the long axis of cyanobiphenyls having the -theta(c) pretilt angle with respect to the rubbing direction.

Selective detection of individual DNA molecules by capillary polymerase chain reaction

On-line capillary polymerase chain reaction (PCR) coupled with laser-induced fluorescence detection was successfully demonstrated for individual DNA molecules. A single 30-microm-i.d. fused-silica capillary was used both as the reaction vessel and for isolating single molecules. SYBR green I dye was added into the reaction mixture for dynamic fluorescent labeling. Because of the small inside diameter of the capillary, PCR-amplified DNA fragments from single molecules were localized in the capillary, providing discrete product zones with concentrations at readily detectable levels. By counting the number of peaks in the capillary via electromigration past a detection window, the number of starting DNA molecules could be determined. With selective primer design, only the molecule of interest was detected. Amplification of the 110-bp fragment from an individual human beta-globin gene and the 142-bp fragment from an individual HIV-1 DNA was demonstrated. This opens the possibility of highly selective and sensitive disease diagnosis at a very early stage.

On-line nanoliter cycle sequencing reaction with capillary zone electrophoresis purification for DNA sequencing

An integrated system for DNA sequencing based on a nanoreactor for cycle-sequencing reaction coupled with on-line capillary zone electrophoresis (CZE) for purification and capillary gel electrophoresis (CGE) for separation is presented. Less than 100 nl of premixed reagent solution, which includes dye-labeled terminator pre-mix, bovine serum albumin and template, was hydrodynamically injected into a fused-silica capillary (75 microm I.D.) inside a laboratory-made microthermocycler for cycle sequencing reaction. In the same capillary, the reaction products were purified by CZE followed by on-line injection of the DNA fragments into another capillary for CGE. Over 540 base pairs (bp) of DNA can be separated and the bases called for single-standed DNA with 0.9% error rate. The total time was about 3.5 h, or a cycle time of 2 h with staggered operation. For double-stranded DNA, a longer reaction time was required and base calling up to 490 bp with 1.2% error rate was achieved. The whole system is readily adaptable to automated multiplex operation for DNA sequencing or polymerase chain reaction analysis.

Multiplexed capillary zone electrophoresis and micellar electrokinetic chromatography with internal standardization

Although liquid chromatography and gas chromatography are the main workhorses in the analytical laboratory, samples can only be analyzed consecutively in an instrument. In this study, capillary zone electrophoresis and micellar electrokinetic chromatography separations are performed in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis.

[Compatible leaching effect of Concha Ostreae and some commonly-used Chinese medicinal materials]

OBJECTIVE

Based on a study of Concha Ostreae, to provide some reference for the rational approach to leaching mineral drugs.

METHOD

Taking the change rates of compatible leaching and value of A as targets, the compatible leaching effect of Concha Ostreae with Radix et Rhizoma Rhei Praeparata, Radix Scutellariae, Pollen Typhae and Fructus Aurantii lmmaturus was studied.

RESULT

If Concha Ostreae and the above cited medicinal herbs are decocted together, the yield of extract may be reduced to a certain extent, but the target composition of Radix et Rhizoma Rhei Praeparata and Fructus Aurantii lmmaturus remains intact, only the content of Radix Scutellariae baicalin may be influenced.

CONCLUSION

The relationship of technology with preparation must be taken into consideration when making choice of the proper way to leach Concha Ostreae.

[Variation of female migraine after menopause and its prophylaxis and treatment]

320 cases of female migraine after menopause according to the diagnostic criteria were studied by using 1:1 matched analysis. It was found that the additional symptoms increased after menopause. Eighty cases available for follow-up were divided into two groups, on which the treatment tests were done. Each patient in group I took Nilestrioli 2 mg twice a month and Perphenazine 12 mg and Doxepin 75 mg per day, while each patient in group II took Tolfenamic acid 300 mg a day. Two months after treatment, the cure rates were 57.58% in group I and 27.78% in group II. Two monthes after the cessation of therapy, 2 cases had relapses in group I. These data indicate that the decrease of estrin disorder and the additional symptoms after monopause play important roles in the change of migraine physiology, and the corresponding treatment methods are rational.

[Separation and preparation of indole alkaloids in Lycorma delicatula White. by HPLC]

A HPLC method for separating and preparing indole alkaloids is described. HPLC conditions for analysis: BIO-RAD series 700 HPLC, model 700 data station, UV: model 1749 UV-VIS monitor, column: BIO-RAD Hi-pore RP318, 250 mm x 10 mm, mobile phase: 80% methanol-H2O(gradient), flow rate: 1.5 ml/min, detection wavelength: 254 nm. On the basis of spectral (1HNMR, 13CNMR, H-H COSY, MS, DEPT) and chemical evidence, the structures of two compounds were elucidated as beta-yohimbine (yohimban-16-carboxylic acid-17-hydroxy methylester (3 alpha, 16 alpha, 17 beta)) and ajmalicine (oxayohimban-16-carboxylic acid-16,17-didehydro-19-ethyl methyl ester (19 alpha)).

Carcinoma of the minor salivary glands: results of surgery and combined therapy

PURPOSE

This article reports the results of treatment of 7 histologic types of minor salivary gland carcinoma.

PATIENTS AND METHODS

Of 256 cases, local excision was used in 194, extended excision in 62, excision accompanied by neck dissection in 98, and surgery with adjunctive radiation therapy or chemotherapy in 101. Forty-five of the 98 neck dissection cases had cervical node metastases.

RESULTS

Survival rates were analyzed for 233 patients. The 3-year survival rate was (167 of 215) (77.67%), the 5-year survival rate was 134 of 187 (71.76%), and the 10-year survival rate was 79 of 113 (69.91%).

CONCLUSIONS

These data confirm that surgery is still the mode of choice in the treatment of minor salivary gland carcinoma, but a combination with radiation therapy or chemotherapy is advisable in some patients.

[The indication and technique in total correction of tetralogy of Fallot: experiences in 212 patients]

Two hundred and twelve consecutive patients underwent total correction of tetralogy of Fallot at Fuwai Hospital in Beijing between Sept. 1987 to Dec. 1993. They were 131 males and 81 females. Their age ranged from 1 year and 6 months to 37 years. 53 patients were more than 16 years old. Most of them had a typical symptoms and manifestations like cyanosis and clubbing fingers etc. Their HB ranged 155 to 325g/L (mean 21.2 +/- 3g/L). It was more thant 180g/L in 134 patients. SBE was complicated in one patient and reoperation was performed in 3 patients. Maldevelopment or hypoplasia of pulmonary artery and left ventricle were found in 52 patients. Only 2 patients died from nonsurgical cause postoperatively. The mortality was 0.9%. The remaining patients recovered uneventfully. The results suggested that hypoplastic pulmonary artery and left ventricle were not a absolute contraindication of total correction of tetralogy of Fallot. The high hematocrit was also not a high risk factor for death. The key was to correct the pathology completely and manage the complications properly.

[Some new concepts of cardiac myxoma]

The surgical treatment of cardiac myxoma in 211 consecutive cases (single tumor in 204 cases, multiple in 7, and recurrent in 3) from Dec. 1975 through Dec. 1993 was reviewed. Totally 228 myxomas were found and 215 operations performed. Data from this series and literature show that there were some complicated cases so that cardiac myxoma can not be simply regarded as a benign tumor only, but may be classified into two kinds: simple (or sporadic) cardiac myxoma and complicated cardiac myxoma. The latter includes myxoma complex, familial myxoma, and myxoma from multicenters. The clinical features, main points of diagnosis and surgery are concisely summarized.

Clinical analysis of steroid glaucoma

PURPOSE

The authors accumulated 15 cases (26 eyes) of steroid glaucoma due to topical administration of dexamethasone or prednisolone.

METHODS

From 1970 to 1990, 26 eyes in 15 cases were observed (bilateral 11 cases, unilateral 4 cases) including 12 right eyes and 14 left eyes. 10 cases were male and 5 cases female with age ranging from 14 to 52 years averaging 28 years. 25 eyes had the manifestation of chronic open angle glaucoma in the clinical course, and 1 eye simulated an acute glaucoma attack.

RESULTS

All patients had taken antiglaucoma medication before coming to our hospital, but the IOP was over 6.7 kPa in 9 eyes. The C/D ratio was equal to or over 0.6 in 9 cases (16 eyes), and the values were inconsistent between both eyes in 55% of the patients. Treatment for glaucoma was immediate discontinuation of the steroids with antiglaucoma medication if necessary. Three eyes received filtering operations and 2 eyes had the removal of subconjunctival residual steroid. Normal IOP was restored in months up to a year.

CONCLUSION

Dexamethasone or prednisolone were the easiest to induce steroid glaucoma when the patients had long-term use of steroid eyedrops.