Biomedical subjects
Publications and source records attributed to Shi-Wei Zhang.
The first asymmetric synthesis of 1,3-dinitro compounds through Michael addition of nitroalkanes to nitroalkenes catalyzed by C2-symmetric chiral tridentate bis(oxazoline) and bis(thiazoline) zinc complexes was achieved with high enantioselectivities (up to 95% ee).
[reaction: see text] A series of new chiral C(3)-symmetric tris(beta-hydroxy phosphoramide) ligands have been synthesized via the reaction of trisphosphoramide ester and Grignard reagents. The catalytic asymmetric borane reduction of ketones with these new C(3)-symmetric chiral tris(beta-hydroxy phosphoramide)s was investigated. Structurally well-defined, recoverable ligand 1d is an efficient catalyst for the enantioselective borane reduction of both electron-deficient and electron-rich ketones, and high enantioselectivities were achieved (up to 98% ee).
OBJECTIVE: To analyze and reduce the omission factors in detecting early stage prostate cancer by TRUS needle biopsy, and to improve the diagnosis of the disease. METHODS: A total of 80 benign prostatic hyperplasia patients suspected of prostatic carcinoma underwent TRUS sextant biopsies. The pathological results being negative, the patients received transurethral resection of the prostate (TURP). RESULTS: After TURP, 25 cases were pathologically diagnosed as prostate cancer, with an omission rate of 31.25% (25/80). Of the diagnosed cancer patients, 10 were treated by radical perineum prostatectomy, 8 by surgical castration, and 7 by medical castration. CONCLUSION: Some tumors may fail to be detected by TRUS needle biopsy. Serial or multi-core needle biopsies can decrease the omission rate in the diagnosis of organ confined cancer.
Three isomorphous compounds M(CHOO)3[NH2(CH3)2] (M = Mn(1 x Mn), Co(2 x Co), Ni(3 x Ni)) have been synthesized in solvothermal conditions. Single-crystal X-ray diffraction shows that they are all crystallized in the trigonal space group R c with small differences in the lattice parameters. Bridged by the three-atom single-bridge CHOO-, M ions form a three-dimensional distorted perovskite-like structure with dimethylamine (DMA) cations located in the cages of the network. Based on the magnetic data, these three 3D compounds are weak ferromagnets with the critical temperature Tc = 8.5 K (1 x Mn), 14.9 K (2 x Co), and 35.6 K (3 x Ni), and for 2 x Co and 3 x Ni, spin reorientation might take place at 13.1 and 14.3 K, respectively. At 1.8 K, hysteresis loops can be observed for all three compounds with the coercivity field ca. 90 Oe (1 x Mn), 920 Oe (2 x Co), and 320 Oe (3 x Ni). The canting angles are estimated to be 0.08 degrees, 0.5 degrees, and 0.6 degrees for 1 x Mn, 2 x Co, and 3.Ni, respectively. The magnetic coupling between MnII ions in 1.Mn was estimated based on the model developed by Rushbrook and Wood for a Heisenberg antiferromagnet on a simple cubic lattice and the best fit gives J = -0.23 cm(-1). At the same time, according to molecular field theory of antiferromagnetism, the J values for compounds 1 x Mn, 2 x Co, and 3 x Ni were estimated to be -0.32 cm(-1), -2.3 cm(-1), and -4.85 cm(-1), respectively. The spin cant in these compounds may originate from the noncentrosymmetric character of the three-atom single-bridge CHOO-. Furthermore, amorphous materials 4 x Mn238, 5 x Mn450, 6 x Co320, and 7 x Ni300 were prepared from precursors 1-3 under an argon atmosphere at different temperatures according to the thermogravimetric analyses. As an interesting result, 5 x Mn450 was confirmed to be an amorphous form of Mn3O4 with a considerably large coercivity field HC = 4.1 kOe at 30 K compared to that value (250 Oe) for bulk Mn3O4.
Cyano-bridged corrugated ladder-like chains are connected by mu(1,1)-N(3) (end-on, EO) bridges to form a layered coordination polymer, [Mn(N(3))(CH(3)OH)[Cr(phen)(CN)(4)].CH(3)OH (2), which is the first mixed cyano-azide bridged compound, and shows metamagnetism below 21.8 K, a temperature much higher than that (3.4 K) of the crossed double chain [Cr(phen)(CN)(4)](2) [Mn(H(2)O)(2)].4H(2)O (1) based on the same building block [Cr(phen)(CN)(4)](-).
OBJECTIVE: To investigate the clinical outcome of sigma rectum pouch as a continent form of urinary diversion. METHODS: The clinical data of 38 patients, 32 males and 7 females, aged 53.2 (42 - 68) with muscle-invading bladder carcinoma who underwent a Mainz pouch II procedure after radical cystectomy 1996 - 2001 were analyzed. The intestine was incised over a length of 20 - 24 cm with the junction of sigmoid colon and rectum as the midpoint so as to create a low-pressure reservoir for urine and side-to-side anastomosis was performed on the posterior borders of the rectosigmoid wall. Submucosal tunnel technique was employed in antireflux urethral implantation. The patients were followed up for 7 - 60 months with a mean of 30 months postoperatively. RESULTS: Continence has been achieved in all the 38 patients with a micturition frequency of 3 - 5 times during daytime and 0 - 3 times at night. The mean volume of pouch was 515.6 ml (400 - 650 ml). The basal intra-reservoir pressure was 8 - 23 cm H(2)O (mean 16.5 cm H(2)O, 1 cm H(2)O = 0.098 kPa), the highest peak pressure was 12 - 33 cm H(2)O (mean 21.3 cm H(2)O). CONCLUSION: A modified sigmoid rectal pouch procedure provides a reservoir with a higher capacity and lower pressure without a reflux to the upper urinary tract and descending colon with lower incidence of complication, it is also a better alternative diversion procedure that would be easily accepted by surgeons and patients.
Allenyl alcohols such as 4-hydroxybuta-1,2-dienes and 5-hydroxypenta-1,2-dienes having a variety of substituents undergo cyclocarbonylation in the presence of a ruthenium catalyst under mild conditions selectively to give five- and six-membered lactones in a high yield with 100% atom economy. 5-Aminopenta-1,2-dines are also cyclocarbonylated to give gamma-lactams. A possible carbonylation mechanism involving a ruthenium cluster intermediate is proposed on the basis of experimental results.
Two three-dimensional (3D) malonate bridged networks, [Cu(mal)(DMF)](n) (1) and [[Cu(mal)(0.5pyz)].H(2)O](n) (2), have been synthesized in H(2)O-DMF solution. Compound 1 exhibits ferromagnetic ordering below 2.6 K (T(c)), and 2 displays a metamagnetic behavior below 3.2 K (T(N)).
Indicators providing highly sensitive and functional group specific fluorescent response to diisopropyl fluorophosphate (DFP, a nerve gas (G-agent) simulant) are reported. Nonemissive indicator 2 reacts with DFP to give a cyclized compound 2+A- that shows a high emission due to its highly planar and rigid structure. Very weak emission was observed by the addition of HCl. Another indicator based on pyridyl naphthalene exhibits a large shift in its emission spectrum after reaction with DFP, which provides for quantitative ratiometric detection.
From the reduction of heptamolybdate, a polyoxomolybdate was obtained with the formula [Na(6)(+)(H(2)O)(16)(NH(2)CH(2)COO)(2)(-)](4+).[Na(+)[H(9)Mo(10)(VI)Mo(8)(V)O(56)(NH(2)CH(2)COO)(2)(-)](5-)](4-).20H(2)O, i.e. heptasodium nonahydrogen tetracarbamate hexadecaaquahexapentacontaoxaoctadecamolybdate(V,VI) icosahydrate. The 18 Mo atoms are connected by bridging O atoms to form a centrosymmetric girdle-like structure, in which Mo(V)-Mo(V) units are found. An Na(+) cation occupies the central hole of the girdle, while four Na(+) cations are bonded to the O atoms on the girdle edge. The girdles are linked into a one-dimensional chain by the other Na(+) cations.