Biomedical subjects

Juan Han

Publications and source records attributed to Juan Han.

13 recordsLinked to original sources

PubMed2006

Spectroscopic study of orange G-beta-cyclodextrin complex and its analytical application.

The mechanism of the inclusion of orange G and beta-cyclodextrin (beta-CD) has been studied by using both spectrophotometry and infrared spectroscopy. Effects of the pH, concentrations of beta-CD, and ionic strength on the inclusion complex of beta-CD and orange G were examined. The result showed that orange G reacts with beta-CD to form a 1:1 host-guest complex with an apparent formation constant of 3.03 x 10(3)mol(-1)l. The thermodynamic parameters of inclusion complex, DeltaG(0), DeltaH(0), and DeltaS(0) were obtained. Based on the enhancement of the absorbance of orange G produced through complex formation, a ratiometric method spectrophotometrically for the determination of orange G in bulk aqueous solution in the presence of beta-CD was developed, which overcome the effect of condition change on the determination of orange G. The linear relationship between the absorbance and orange G concentration was obtained in the range of 1.0 x 10(-5) to 4.0 x 10(-5)mol l(-1), with a correlation coefficient of 0.9998. The detection limit was 3.6 x 10(-6)mol l(-1). The principal advantage of the proposed method is high accuracy because ratiometry was used in measurement.

Anions↗

PubMed2006

[Case control study on risk factors of congenital microtia].

OBJECTIVE: To identify the risk factors associated with congenital microtia. METHODS: A case-control, retrospective study was performed. A total of 207 cases of congenital microtia and 209 age-frequently-matched controls were interviewed individually according to the uniform questionnaire. The questionnaire included: (1) Essential information about patients and their parents. (2) First trimester diseases and medication of mother. (3) Past gestation history of mother. (4) Family history and life style of the parent. The available data were analyzed by chi-square test and multivariate Logistic regression model. RESULTS: The factors, such as gender (OR = 5.893), first trimester disease of mother (OR = 34.49) and medication (OR = 4.299), excessive drinking and smoking of father (OR = 4. 347, OR = 4.304), non-primiparous parity (OR = 9.524), abortion (spontaneous and induced, OR = 1.723), low-education of mother (OR = 2.275) were risk factors contributing to microtia in multivariate study. The factors, such as tea (OR = 0.179) were protective factors in multivariate study. CONCLUSIONS: Multi-risks factors are contributing to microtia. Preventive measures according to risk factors should be put forward.

Case-Control Studies↗

PubMed2006

[Ear reconstruction using soft tissue expander in the treatment of congenital microtia].

OBJECTIVE: To explore surgical procedure of congenital microtia. METHODS: Ear reconstruction was made using soft tissue skin expander and autogenous rib cartilage framework. RESULTS: Long time follow-up showed that the flap of reconstructed ear was ruddy, soft, with normal sensory function; cartilage framework had no degeneration, absorption and deformation. In addition, the reconstructed ears were coincidence with the normal side on location, form and dimension. CONCLUSIONS: It was a good method for congenital microtia to use soft tissue skin expander together with autogenous rib cartilage framework at present time.

Child↗

PubMed2005

Study of inclusion complex formation between tropaeolin OO and beta-cyclodextrin by spectrophotometry and Infrared spectroscopy.

The mechanism of the inclusion of tropaeolin OO (TPOO) and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The inclusion depth of the guest molecule in the host molecule was demonstrated by infrared spectrometry. Effect of the pH, concentrations of beta-CD, solvents and ionic strength on the inclusion of TPOO and beta-CD were examined. The result showed that TPOO reacts with beta-CD to form a 1:1 host-guest complex with an apparent formation constant of 1.50 x 10(3) l mol(-1). The thermodynamic parameters of inclusion reaction, DeltaG degrees , DeltaH degrees and DeltaS degrees were obtained.

Azo Compounds↗

PubMed2005

Spectrophotometric study of the inclusion complex between beta-cyclodextrin and dibenzoyl peroxide and its analytical application.

The noncovalent interaction of dibenzoyl peroxide and beta-cyclodextin (beta-CD) has been studied by spectrophotometry. The mechanism of the inclusion was studied. The results showed that beta-CD reacts with dibenzoyl peroxide to form a 2:1 host-guest complex with an apparent formation constant of 2.5 x 10(4)mol(-2)L(2). The beta-CD reacts with benzoic acid to form a 1:1 host-guest complex with an apparent formation constant of 6.9 x 10(2)mol(-1)L after the dibenzoyl peroxide was reduced by hydroxyl ammonium. Based on the enhancement of the absorbance of dibenzoyl peroxide produced through complex formation, a spectrophotometric method for determination of dibenzoyl peroxide in bulk aqueous solution in the presence of beta-CD was developed. A linear relationship between the absorbance and dibenzoyl peroxide concentration was obtained in the range of 0.300-50.0 microg mL(-1). Linear regression equation of the calibration graph C=0.02926+53.25 A, with a correlation coefficient of 0.9984 and a relative standard deviation (R.S.D.) of 3.4%. The detection limit was 0.200 microg mL(-1), and the recovery was from 98.00 to 105.0%. The proposed method was used to determine the dibenzoyl peroxide in the flour with satisfactory results. The principal advantage of the proposed method is its excellent selectivity based on molecule recognition of beta-CD.

Benzoyl Peroxide↗

PubMed2005

Simultaneous determination of dopamine and carvedilol in human serum and urine by first-order derivative fluorometry.

A sensitive and selective method for simultaneous determination of carvedilol and dopamine was described. The emission wavelengths of carvedilol and dopamine were at 354 nm and 314 nm with the excitation at 290 nm, respectively. The determination of carvedilol and dopamine by normal fluorometry was difficult because the emission spectra of carvedilol and dopamine were overlapped seriously. The first derivative peaks of carvedilol and dopamine were at 336 nm and 302 nm, respectively. The linear regression equations of the calibration graphs of carvedilol and dopamine were C = 0.000557H-0.00569 and C = 0.00438H-0.0812, with the correlation coefficients were 0.9953 and 0.9988, respectively. The liner range for the determination of carvedilol was 0.002 microg ml(-1) to 0.02 microg ml(-1), and 0.05 microg ml(-1) to 0.6 microg ml(-1) for dopamine. The detection limits were 1 ng ml(-1) for carvedilol and 0.04 microg ml(-1) for dopamine, respectively. The relative standard derivative (RSD) of 4.38% and 4.35% was observed for carvedilol and dopamine, respectively. The recovery of carvedilol was from 95.00% to 106.7% in human serum and from 97.50% to 105.0% in urine sample. The recovery of dopamine was from 100.0% to 102.5% in human serum and from 97.50% to 105.0% in urine sample. This method is simple and can be used for determination of carvedilol and dopamine in human serum and urine sample with satisfactory results.

Calibration↗

PubMed2005

Simultaneous determination of carvedilol and ampicillin sodium by first-derivative fluorometry in the presence of human serum albumin.

A sensitive and selective method for the simultaneous determination of carvedilol and ampicillin sodium (AS) in the presence of human serum albumin (HSA) is described. The maximum emission wavelengths of carvedilol and AS are at 357 nm and 426 nm with excitation at 254 nm, respectively. The first-derivative peaks of carvedilol and AS were at 337 nm and 398 nm, respectively. The linear-regression equations of the calibration graphs of carvedilol and AS were C = 0.0001H - 0.0063 and C = 1.530H - 43.84; the correlation coefficients were 0.9990 and 0.9986, respectively. The detection limits were 1 ng ml(-1) for carvedilol and 23 microg ml(-1) for AS, respectively. The effects of the pH, the stability of carvedilol and AS and foreign ions on the determination of carvedilol and AS were examined. The recoveries of carvedilol and AS were measured. This method is simple and can be used for the determination of carvedilol and AS in human serum and urine samples with satisfactory results.

Adrenergic beta-Antagonists↗

PubMed2005

[Effects of L-arginine on the microcirculation of rat island skin flaps after ischemia- reperfusion].

OBJECTIVE: To investigate the effects of L-arginine on the microcirculation and survival of rat island skin flaps after ischemia-reperfusion. METHOD: A right lower abdominal island flap was created in SD rats and the microcirculatory blood flow in these flaps measured with laser Doppler velocimetry following L-arginine injection via the contralateral femoral artery. Both NO and malondialdehyde (MDA) levels in the flaps were assayed and the survival of the flaps replanted in situ was evaluated 1 week later. RESULTS: L-arginine treatment caused increase in the microcirculatory blood flow of the flaps and elevation of NO while and decrease of MDA levels. The survival rate of the flaps with L-arginine treatment was significantly higher than the flaps from saline-treated and normal rats. CONCLUSION: L-arginine can improve the survival of island flap through increasing the microcirculatory blood flow and lessening ischemia-reperfusion injury of the flaps.

Animals↗

PubMed2005

Study on self-consciousness of children with learning disabilities and related factors.

OBJECTIVE: To study the self-consciousness of children with learning disabilities (LD) and to identify related factors. METHODS: Five hundred and sixty pupils graded from 1 to 6 in an elementary school were investigated. According to the pupil rating scale revised screening for learning disabilities (PRS), combined Raven's test (CRT) and achievement of main courses, 35 of 560 pupils were diagnosed as LD children. Thirty-five children were selected from the average children and 35 from advanced children in academic achievement equally matched in class, gender, and age with LD children as control groups. The three groups were tested by Piers-Harris children's self-concept scale. Basic information of each subject was collected by self-made questionnaire. RESULTS: Compared with the average and advanced children, LD children got significantly lower scores in self-concept scale. Based on logistic regression analysis, 3 factors were identified, including family income per month, single child and delivery model. CONCLUSION: The results suggest that self-consciousness of children with LD is lower than that of normal children.

Child↗

PubMed2004

The first slipped pseudo-quadruple-decker complex of phthalocyanines.

The first slipped pseudo-quadruple-decker complex of phthalocyanines was formed unexpectedly upon treatment of the protonated double-decker SmIIIH(Pc)[Pc(alpha-OC4H9)8] with NaOH. The supramolecular structure contains two double-decker units linked by two sodium ions by an extremely rare coordination mode of phthalocyanines in which an aza nitrogen atom and two oxygen atoms from neighboring alkoxy substituents form a tridentate ligand.

Journal Article↗

PubMed2004

Spectrophotometric determination of dapsone in pharmaceutical products using sodium 1,2-naphthoquinone-4-sulfonic as the chromogenic reagent.

Spectrophotometric determination of dapsone is described. The dapsone reacts with sodium 1,2-naphthoquinone-4-sulfonic in pH 6.98 buffer solution to form a salmon pink compound, and its maximum absorption wavelength is at 525 nm, epsilon525=3.68 x 10(4) l mol(-1) cm(-1). The absorbance of dapsone from 0.40 to 10 microg ml(-1) obeys Beer's law. The linear regression equation of the calibration graph is C=0.2334 A + 0.01288, with a linear regression correlation coefficient of 0.9998, the detection limit is 0.24 microg ml(-1), and recovery is from 99.2 to 102.4%. Effects of pH, surfactant, organic solvents, foreign ions, and standing time on the determination of dapsone have been examined. This method is simple and can be used for the determination of dapsone in injection solution of dapsone. The results obtained by this method agreed with those by the official method (dead-stop titration method [The Chinese Pharmacopoeia, Pharmacopoeia Commission, Ministry of Health, vol. 2, fifth ed., PRC Chemical Industry Press, Beijing, 2000, p.720]).

Antimalarials↗

PubMed2002

[Reconstruction of the external ear utilizing expanded scarred skin flap].

OBJECTIVE: To investigate the feasibility of ear reconstruction using local expanded scarred skin flap. METHOD: We used local postauricular expanded scar skin flaps to reconstruct external ear in 24 patients. RESULTS: Of these cases, 22 flaps survived completely. In 2 patients, the cartilage framework exposed over the upper pole of helix region because of undue tension in suturing the tissue edges. One year's follow-up revealed satisfactory results. CONCLUSION: Using the expanded scarred skin flap for ear reconstruction is practical and effective, when there's no normal skin available in the local area.

Adolescent↗

PubMed2002

[Surgical depilation in low hairline aurical reconstruction].

OBJECTIVE: Low hairline is one of the most troublesome problem in auricle reconstruction. There was no satisfactory way to manage the problem. This article discuss surgical depilation to deal with this problem and reconstructed auricle. METHODS: According to the degree of the low hairline, Postaurical scalp was expanded and part of the lower follicles within the dermal were removed, or postaurical scalp that part of lower follicles and dermal had been removed was expanded and covered skeleton of ear with this expanded skin to reconstructed auricle. RESULTS: Auricles were reconstructed with this method in 152 lowhairline microtial cases, the result was very satisfactory. CONCLUSION: This procedure is an effective way to deal with low hairline in reconstructing auricle.

Adolescent↗