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Biomedical subjects

Y S Shen

Publications and source records attributed to Y S Shen.

At least 19 recordsLinked to original sources
PubMed2002

Decomposition of gas-phase trichloroethene by the UV/TiO2 process in the presence of ozone.

The decomposition of gas-phase trichloroethene (TCE) in air streams by direct photolysis, the UV/TiO2 and UV/O3 processes was studied. The experiments were carried out under various UV light intensities and wavelengths, ozone dosages, and initial concentrations of TCE to investigate and compare the removal efficiency of the pollutant. For UV/TiO2 process, the individual contribution to the decomposition of TCE by direct photolysis and hydroxyl radicals destruction was differentiated to discuss the quantum efficiency with 254 and 365 nm UV lamps. The removal of gaseous TCE was found to reduce by UV/TiO2 process in the presence of ozone possibly because of the ozone molecules could scavenge hydroxyl radicals produced from the excitation of TiO2 by UV radiation to inhibit the decomposition of TCE. A photoreactor design equation for the decomposition of gaseous TCE by the UV/TiO2 process in air streams was developed by combining the continuity equation of the pollutant and the surface catalysis reaction rate expression. By the proposed design scheme, the temporal distribution of TCE at various operation conditions by the UV/TiO2 process can be well modeled.

Air Pollutants↗
PubMed2001

Nonoperative treatment versus posterior fixation for thoracolumbar junction burst fractures without neurologic deficit.

STUDY DESIGN: A prospective clinical trial was conducted. OBJECTIVE: To compare the results of nonoperative treatment versus short-segment posterior fixation using pedicle screws. SUMMARY OF BACKGROUND DATA: A previous study showed that nonoperative treatment with early mobilization produced good results, even when the posterior column was involved. METHODS: This study involved 80 patients. Inclusion criteria required the following: neurologically intact patient, single-level closed burst fracture involving T11-L2, no fracture dislocations or pedicle fractures, age of 18 to 65 years (nonpathologic adult), and no other major organ system or musculoskeletal injuries. Patients in the nonoperative group (n = 47) were allowed activity to the point of pain tolerance beginning on the day of injury using a hyperextension brace. Patients in the operative group (n = 33) underwent three-level, (one above, one at fracture level, and one below) fixation using VSP or TSRH instrumentation. The follow-up period was 2 years. RESULTS: The surgical group had less pain up to 3 months and a better Greenough Low Back Outcome Score up to 6 months, but the outcome was similar afterward. No neurologic deficit in any patient. In the nonoperative group, the kyphosis angle worsened by 4 degrees, and the retropulsion decreased from 34% to 15%. In the operative group, there was one case of superficial infection and two cases of broken screws. The kyphosis angle was improved initially by 17 degrees, but this was gradually lost. Hospital charges were four times higher in the operative group. CONCLUSIONS: Short-segment posterior fixation provides partial kyphosis correction and earlier pain relief, but the functional outcome at 2 years is similar. Early activity to the point of pain tolerance can be safely allowed.

Adult↗
PubMed2001

[Study on effect of jinshui liujun jian oral liquid on serum superoxide dismutase activity and malonyldialdehyde content in mice with chronic bronchitis].

OBJECTIVE: To study the effect of Jinshui Liujun Jian Oral Liquid (JLJOL) on serum superoxide dismutase (SOD) activity and malonyldialdehyde (MDA) content in mice with chronic bronchitis. METHODS: JLJOL was given to the chronic bronchitis mice model (induced by smoking) through gastrogavage, and then SOD activity and MDA content were tested. RESULTS: SOD activity in model mice after JLJOL treatment was 0.67 +/- 0.15 NU/L, which was significantly higher than that in the untreated model (0.39 +/- 0.13 NU/L, P < 0.01). But the MDA content in treated mice was significantly lower than that in untreated one (9.26 +/- 2.90 nmol/L vs 16.07 +/- 5.62 nmol/L, P < 0.01). CONCLUSION: JLJOL could scavenge the injury of free radical on organism.

Animals↗
PubMed2000

Reaction behaviors of decomposition of monocrotophos in aqueous solution by UV and UV/O processes.

The decomposition of monocrotophos (cis-3-dimethoxyphosphinyloxy-N-methyl-crotonamide) in aqueous solution by UV and UV/O(3) processes was studied. The experiments were carried out under various solution pH values to investigate the decomposition efficiencies of the reactant and organic intermediates in order to determine the completeness of decomposition. The photolytic decomposition rate of monocrotophos was increased with increasing solution pH because the solution pH affects the distribution and light absorbance of monocrotophos species. The combination of O(3) with UV light apparently promoted the decomposition and mineralization of monocrotophos in aqueous solution. For the UV/O(3) process, the breakage of the >C=C< bond of monocrotophos by ozone molecules was found to occur first, followed by mineralization by hydroxyl radicals to generate CO(3)(2-), PO4(3-), and NO(3)(-) anions in sequence. The quasi-global kinetics based on a simplified consecutive-parallel reaction scheme was developed to describe the temporal behavior of monocrotophos decomposition in aqueous solution by the UV/O(3) process.

Absorption↗
PubMed1999

Nonsurgical treatment of three-column thoracolumbar junction burst fractures without neurologic deficit.

STUDY DESIGN: Retrospective review of the outcome of neurologically intact patients with three column thoracolumbar junction burst fractures that were treated nonsurgically. OBJECTIVE: To further define the parameters for nonsurgical management of thoracolumbar junction burst fractures. SUMMARY OF BACKGROUND DATA: Many texts list involvement of the posterior column as an indication for surgery and state that casting or bracing is mandatory. This has not been the authors' experience. METHODS: Thirty-eight patients with nonpathologic, single-level burst fractures of T11, T12, L1, or L2, and with posterior element fractures were studied retrospectively. The selection criteria required that the patient be neurologically intact, that the pedicles and facet joints not be fractured or dislocated, and that the angle of kyphosis be less than 35 degrees. The extent of retropulsion, loss of vertebral height, and presence of lamina or process fractures were not criteria. No attempt was made to reduce the fracture. Patients were allowed immediate ambulation as tolerated. Jewett braces were used in nine patients, but no bracing was used in the remainder. RESULTS: There were 22 males, 16 females. Median age 37 years (range, 16-65). Fracture involved both endplates in 16 patients (12 crush-cleavage type), the superior end-plate in 21, and the inferior endplate in 1. The hospital stay was from 2 to 18 days (median, 8 days). Follow-up averaged 4.1 years (range, 2.1-6.3). All patients remained neurologically intact. Eight patients had no pain, 24 had minimal pain, 4 had moderate pain, and 2 had moderate to severe pain. Twenty-nine of 38 patients (76%) were able to work at the same level. The initial kyphosis angle averaged 20 degrees (range 10-35 degrees). At follow-up it averaged 24 degrees (range 12-38 degrees). The maximum increase was 6 degrees. Some degree of retropulsed fragment resorption was noted in 35 cases. Complications were limited to transient urinary retention. There were no thromboembolisms, decubitus ulcers, or pulmonary complications. CONCLUSION: Despite the use of less restrictive criteria, no brace, and early activity as tolerated, the results are similar to those obtained with more restrictive protocols. The presence of vertical lamina fracture, spinous process fracture, and transverse process fracture are not contra--indications. Activity restriction and bracing may be important for pain control but probably does not change the long-term result.

Adolescent↗
PubMed1999

Plate fixation of fresh displaced midshaft clavicle fractures.

From 1992-1994, we operated on 251 fresh completely displaced mid-third clavicle fractures in adults; 232 were followed up. The fractures were plated with a Mizuho C-type plate or an AO/ASIF 3.5 mm reconstruction plate. Comminuted fragments were reduced and wired (133 cases). There were 150 men and 82 women; the median age was 37.3 years (range 18-79). The mean follow-up was 4.4 years (range 3.0-5.9). The mean time to radiographic union was 10 weeks. Seven patients (3%) developed nonunion. Healing with angulation occurred in 14 patients. Deep infection developed in one patient, and superficial infection in four cases; 21 patients reported soreness with changes in the weather and activity; 28 patients had residual skin numbness caudal to the incision. No patient had shoulder droop, and none had impairment of range of motion or shoulder strength. None developed new or late neurovascular impairment; 171 patients eventually had the hardware removed at an average 401 days post operatively. Overall, 94% were satisfied with the procedure. For completely displaced clavicle fractures in adults, plating is a reliable procedure.

Adolescent↗
PubMed1997

[Separation of pharmaceutical enantiomers on column and thin-layer plate of cellulose triacetate].

Microcrystalline cellulose triacetate (CTA) was prepared by heterogeneous acetylation of microcrystalline cellulose and used as liquid chromatographic chiral stationary phase and chiral thin layer plate to separate pharmaceutical enantiomers. The racemic Troegor's base, mathaqualone, chlormezanone and chloroquine were separated on the CTA chiral column and on the CTA chiral plate. 95% ethanol and the mixtures of 95% ethanol and water with different ratio and different pH values were used as mobile phase. The influences of eluent composition, pH and temperature on the chiral separation were discussed. The experimental results indicate that the CTA chiral plate was more sensitive to eluent composition and pH than chiral column possibly because the chiral adsorbent was not swollen on the plate.

Cellulose↗
PubMed1997

[Clinical and experimental study on jinshui liujun decoction in treating chronic bronchitis].

OBJECTIVE: To assess the effect of Jinshui Liujun decoction (JSL) in treating chronic bronchitis. METHODS: The effect of JSL on expelling the phlegm and strengthening the body resistance were observed. RESULTS: JSL was proved to be efficacious in improving immune function of the body and pulmonary ventilatory function (P < 0.01). JSL could not only increase the secretion of rats' trachea mucosa and dilute sputum, but also increase the motion speed of the pigeons' trachea cilia, thus facilitate the removal of sputum. Compared with the normal saline control group, both animal experiments displayed significant statistical difference (P < 0.01), but without significant difference when compared the JSL group with the positive drug Juhong Tanke Ye control group. CONCLUSION: JSL has the effect of resolving phlegm as well as improving human immunological and pulmonary ventilatory functions.

Aged↗
PubMed1993

MR evaluation of tuberculous spondylitis.

A total of 29 proven tuberculous spondylitis patients underwent MR studies. Gd-DTPA enhancement was performed in 10 patients. Contiguous 2 vertebral involvement, subligamental spread of paraspinal abscesses and cord indentation were observed in 93% of the cases. Destruction of the vertebral body occurred in 76%. Intermediate or low T1 signal intensity and high T2 signal intensity were observed by MR. A combination of these characteristic findings strongly suggests the diagnosis of tuberculous spondylitis. Gd-DTPA administration did not facilitate diagnosis. MR examination should be considered as the main imaging modality for patients with suspected tuberculous spondylitis.

Abscess↗
PubMed1993

Fibular nonunion after fixation of the tibia in lower leg fractures.

In 335 extraarticular tibial-fibular fractures treated by open reduction of the tibia, nonunion of the fibula was noted in 15 cases (4.5%). Four of these cases were symptomatic, but resection of the hypertrophic nonunion provided relief of pain. Fixation of the fibula is not necessary in primary treatment of extraarticular lower leg fractures.

Adolescent↗
PubMed1978

Purification and characterization of an acid protease from Monascus kaoliang.

An acid protease from Monascus kaoliang was purified by consecutive applications of fractional acetone precipitation, batchwise CM-cellulose method and DEAE-cellulose column chromatography. The preparation was homogeneous on disc polyacrylamide gel electrophoresis at pH 4.5 and 7.5. The yield was about 30% with overall increase in specific activity of about 6-fold. The molecular weight as determined by SDS gel electrophoresis was about 34,000. The enzyme was a glycoprotease as indicated by specific carbohydrate staining on gels. It possessed the nature of an acid protease with a pH optimum at 3.0 toward heat-denatured casein and was stable over the range of pH 3.0 to 6.0. Reducing agents and thiol poisons had no effect on this enzyme, suggesting that free sulfhydryl groups were not required for enzyme activity. Diisopropyl fluorophosphate did not inactivate this protease, indicating the probable absence of serine residue in the active site. The enzyme was inactivated by reaction with the carboxy-group specific reagent, 1,2-epoxy-3-(p-nitrophenoxy) propane (EPNP). Pepstatin, a specific inhibitor for pepsin, was shown to inhibit this enzyme strongly. However, biacetyl (2,3-butadione) had little effect on this protease, although it inactivated pepsin to an 85% activity loss. Also, p-bromophenacyl bromide, another specific inhibitor of pepsin, failed to inactivate this acid protease.

Amino Acids↗
PubMed1975

Abduction contracture of the hip in children.

Nine cases of abduction contracture of the hip in children from contracture of the gluteus maximus muscle are reported. Division of the aponeurosis glutens maximus over the greater trochanter always permitted full adduction.

Adolescent↗