Biomedical subjects

Hong-Bin Xie

Publications and source records attributed to Hong-Bin Xie.

6 recordsLinked to original sources

PubMed2006

Ylidic radical-molecule reactions.

The known reactions between a neutral radical and a neutral closed-shell sigma-type molecule are generally associated with the atom/group-abstraction (e.g., CN, OH reactions) or the carbenoid insertion processes (e.g., CH reactions). In this article, we describe a new type of neutral radical-molecule reaction that feature the nucleophilic addition and elimination mechanism based on the systematic Gaussian-3//MP2(full)/6-31G(d) investigations on the PH(3)CH+HX model reactions (X = CH(3), NH(2), OH, F, CH(2)F, CHF(2), CF(3), NHCH(3)/CH(2)NH(2), OCH(3)/CH(2)OH). The novel properties are found to benefit both from the radical and ylidic characters of PH(3)CH, and the type of reagent HX determines the nucleophilic addition reactivity. The present work is the first study on the chemical reactivity of the ylidic radicals.

Computer Simulation↗

PubMed2006

Radical reaction C3H+NO: a mechanistic study.

Although a number of hydrocarbon radicals including the heavier C(3)-radicals C(3)H(3) and C(3)H(5) have been experimentally shown to deplete NO effectively, no theoretical or experimental attempts have been made on the reactivity of the simplest C(3)-radical towards NO. In this article, we report our detailed mechanistic study on the C(3)H+NO reaction at the Gussian-3//B3LYP/6-31G(d) level by constructing the singlet and triplet electronic state [H,C(3),N,O] potential energy surfaces (PESs). The l-C(3)H+NO reaction is shown to barrierlessly form the entrance isomer HCCCNO followed by the direct O-elimination leading to HCCCN+(3)O on triplet PES, or by successive O-transfer, N-insertion, and CN bond-rupture to generate the product (1)HCCN+CO on singlet PES. The possible singlet-triplet intersystem crossings are also discussed. Thus, the novel reaction l-C(3)H+NO can proceed effectively even at low temperatures and is expected to play an important role in both combustion and interstellar processes. For the c-C(3)H+NO reaction, the initially formed H-cCCC-NO can most favorably isomerize to HCCCNO, and further evolution follows that of the l-C(3)H+NO reaction. Quantitatively, the c-C(3)H+NO reaction can take place barrierlessly on singlet PES, yet it faces a small barrier 2.7 kcal/mol on triplet PES. The results will enrich our understanding of the chemistry of the simplest C(3)-radical in both combustion and interstellar processes, which to date have received little attention despite their importance and available abundant studies on its structural and spectroscopic properties.

Computer Simulation↗

PubMed2006

Theoretical study on structures and stabilities of [H,Ge,C,N].

Theoretical investigations are performed for the first time on the simplest hydrogenated germanium cyanide [H,Ge,C,N], whose analogs [H,C(2),N] and [H,Si,C,N] have been detected in space and laboratory, respectively. The detailed potential energy surfaces in both singlet and triplet states are constructed at the CCSD(T)/6-311+G(3df,2p)//B3LYP/6-31G(d)+ZPVE level, including 18 minimum isomers and 26 interconversion transition states. The former three low-lying and kinetically stabilized isomers are HGeCN (1)1 (0.0 kcal/mol), HGeNC (1)2 (5.1 kcal/mol), and cyclic cCHNGe(1)7 (11.1 kcal/mol). In addition, five isomers HCNGe (1)3 (33.8), HNCGe (1)5 (29.8), cNHCGe (1)8 (37.9), HGeCN (3)1 (30.1), and HNCGe (3)5 (26.5) each have considerable barriers, despite their high energies. Future laboratory characterization and astrophysical detection of the eight [H,Ge,C,N] isomers, especially the former three low-lying species (1)1, (1)2, and (1)7, are highly recommended. The accurate spectroscopic data at the QCISD/6-311G(d,p) level are provided. For some species, the CBS-QB3 calculations are also performed. Wherever possible, comparisons with the analogous [H,C(2),N] and [H,Si,C,N] are made on the structural, energetic, and bonding properties.

Chemical Phenomena↗

PubMed2005

[Implementation analysis of public functions of centers of disease prevention and control of China].

OBJECTIVE: To evaluate the implementation of public function and items of the centers of disease prevention and control(CDC). METHODS: 161 centers of disease prevention and control have been investigated by two-stage stratified sampling. The implementation analysis of public function and items of CDC is measured by multiplying average operational proportion and average operational degree. RESULTS: 1. For investigated centers, the average rate of function implementation is 42.9% ,with 56.0% at provincial level and 43.7% at city level, 41.3% for the county level; while 49.3% in east areas, 45.4% in middle areas and 35.3% in west areas. 2. Among all 7 functional items, the implemented rate of disease prevention and control is 54.3%, 65.8% for emergency treatment, 35.0% for epidemic situation report and information management of health relative factors, 31.3% for inspection and control of health risk factors, 39.1% for the laboratory examination and evaluation, 36.4% for health education and health promotion, and 56.7% for technological guidance and application study. CONCLUSION: The implemented degree of public function of CDC was generally lower, varied with regions and levels. Among 7 public functional items, the emergency treatment function had the highest implementation, with the lowest for the inspection and control of health relative factors.

China↗

PubMed2005

[Implementation analysis of public functions of 161 centers of disease prevention and control in 7 provinces].

OBJECTIVE: To evaluate the implementation of public function and items of the centers of disease prevention and control (CDC). METHODS: 161 centers of disease prevention and control have been investigated by two-stage stratified sampling. The implementation analysis of public function and items of CDC is measured by multiplying average operational proportion and average operational degree. RESULTS: (1) For investigated centers, the average rate of function implementation is 42.9%, with 56.0% at provincial level and 43.7% at city level, 41.3% for the county level, while 49.3% in east areas, 45.4% in middle areas and 35.3% in west areas. (2) Among all 7 functional items, the implemented rate of disease prevention and control is 54.3%, 65.8% for emergency treatment, 35.0% for epidemic situation report and information management of health relative factors, 31.3% for inspection and control of health risk factors, 39.1% for the laboratory examination and evaluation, 36.4% for health education and health promotion, and 56.7% for technological guidance and application study. CONCLUSION: The implemented degree of public function of CDC was generally lower, varied with regions and levels. Among 7 public functional items, the emergency treatment function had the highest implementation, with the lowest for the inspection and control of health relative factors.

China↗

PubMed2005

[Human resources allocation in centers of disease prevention and control in China].

OBJECTIVE: To compare the human resources allocation of CDC in different areas and different levels. METHODS: By stratified cluster sampling we get 70 CDC's manpower data, which come from different areas(east, middle part, west)and different levels (province, city, county). RESULTS: (1) The average number of CDC's staff is 62. (2)CDC of province level are understaffed by 15%, while CDC of county level are overstaffed by 3%, and CDC of county level are overstaffed by 12%. (3) Structure of age: The average age of CDC's staff is 62, people under 35 years old in CDC is 39.4%, people above 55 years old is 3.5% (4) Structure of education: People with graduate degree are only 0.8%, and people come from technicalsecondary school are 57.0%. (5) Structure of specialty: A majority of people's majors are clinical medicine, and the percent of people having a non-medical-major are 36.6%. (6) Area distributing. Distribution of average quality score of staff are imbalance in different areas, the average quality score of staff in east area are 1.07 times than that in middle area, and 1.12 times than that in west area.

China↗