A new type of implantable drug delivery devices （ DDD ） with complicated architectures were fubricated by three-dimensional printing technique, employing levofloxacin （LVFX） as a model drug. Processing parameters...A new type of implantable drug delivery devices （ DDD ） with complicated architectures were fubricated by three-dimensional printing technique, employing levofloxacin （LVFX） as a model drug. Processing parameters were optimized in riew of the layer thickness, spucing between printed lines, flow rate of liquid binder and the fast axis speed. The prepared DDD prototype consists of a double-layer structure, of which the upper region is a reservoir system and the lower region is a matrix one. The in vitro release test revealed that LVFX was released in a dual-puse pattern. This DDD may present a new strategy for the prophylaxis and treatment of diseases such as bone infection in the near future.展开更多
We present an extended analytical model including the depletion effect and the dimension of ligand-receptor complex, aiming to elucidate their influences on endocytosis of spherocylindrical nanoparticles （NPs）. It i...We present an extended analytical model including the depletion effect and the dimension of ligand-receptor complex, aiming to elucidate their influences on endocytosis of spherocylindrical nanoparticles （NPs）. It is found that the dimension of ligand-receptor complex （δ） and the depletion effect interrelatedly govern the optimal conditions of NP endocytosis. The endocytosis phase diagram constructed in the space of NP radius and relative aspect ratio indicates that the endocytosis of NP is enhanced evidently by reducing the optimal radius and the threshold radius of endocytosed NP. Meanwhile, through thermodynamic and kinetic analysis of the diffusion of receptors, the dependence of diffusion length on depletion effect and the dimension of ligand-receptor complex can be identified in great detail. For small aspect ratio, diffusion length decreases with increasing concentration c of small bioparticles in cellular environment. Endocytosis speed corresponding to large radius R and high concentration c of small bioparticles strongly depends on the increasing （2r-δ）. These results may show some highlights into the conscious design of NPs for diagnostic agents and therapeutic drug delivery applications.展开更多
Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution ...Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution and characterized by X-ray diffraction. 1 crystallizes in the monoclinic space, group P21/n, a = 17.341（6）A, b = 6.744（2）A, c = 34.555（12）A, β = 100.493（6）°, V = 3974（2） A^3, Z = 4. Each copper（H） ion has a distorted octahedral coordination geometry. Nitrate anion adopts the unusual coordination mode linking two adjacent copper（H） ions to form a one-dimensional coordination polymer and these chains are further linked by noncovalent interactions.展开更多
The title complex Mn（H2O）2（HNic）2 （C22H12MnN2O8, Mr = 367.18） crystallizes in monoclinic, space group P21/c with a = 7.5735（8）, b = 12.5295（13）, c = 7.6466（8）A.β = 101.2790（10）°, Z = 2, V= 711.59...The title complex Mn（H2O）2（HNic）2 （C22H12MnN2O8, Mr = 367.18） crystallizes in monoclinic, space group P21/c with a = 7.5735（8）, b = 12.5295（13）, c = 7.6466（8）A.β = 101.2790（10）°, Z = 2, V= 711.59（13） A^3, D, = 1.714 g/cm^3,μ（MoKa） = 0.974 mm^-1, F（000） = 374, R1 （1255 observed reflections （Ⅰ 〉 2σ（Ⅰ）） = 0.0250） and wR2 = 0.0662 （all data）. In this paper, we report the complexation of Mn（Ⅱ） by the bidentate ligand 2-hydroxynicotinic acid （HNic）. In the crystal the Mn（Ⅱ） ion exhibits a deformed octahedron structure. The title complex Mn（H2O）2（HNic）2 has a three-dimensional （3D） network structure extended by hydrogen bonds, which are formed by two typical eight-membered hydrogen-bonded rings.展开更多
This paper uses the concept of algorithmic efficiency to present a unified theory of intelligence. Intelligence is defined informally, formally, and computationally. We introduce the concept of dimensional complexity ...This paper uses the concept of algorithmic efficiency to present a unified theory of intelligence. Intelligence is defined informally, formally, and computationally. We introduce the concept of dimensional complexity in algorithmic efficiency and deduce that an optimally efficient algorithm has zero time complexity, zero space complexity, and an infinite dimensional complexity. This algorithm is used to generate the number line.展开更多
The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt)...The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- .展开更多
Some functional lanthanide metal complexes, such as acetylacetonato complexes, ethylenediaminetetraacetato complexes, were successfully applied for diagnostic technique. The authors are interested in investigating the...Some functional lanthanide metal complexes, such as acetylacetonato complexes, ethylenediaminetetraacetato complexes, were successfully applied for diagnostic technique. The authors are interested in investigating the structure and bonding in lanthanide and actinide metal complexes using 166Er, t55Gd, and 237Np Mtissbauer spectroscopies in connection with single-crystal and/or powder X-ray diffraction, making clear the differences on their structures as well as the differences in the participation of 4f and 5f orbitals in the chemical bonds. In this article, the crystal structures of two novel Gd（Ⅲ） acetylacetonato complexes, Gd（pta）3 · 2H2O （pta = 1,1,1 -trifluoro-5,5-dimethy 1-2,4-hexanedione） and Gd（bfa）3 · 2H2O （bfa = 1, 1, 1 -trifluoro-4-phenyl-2-4-butanedione） were reported. Though both of them were dihydrate and had distorted square antiprismatical structure, Gd（pta）3 · 2H2O crystallizes in the P 2 1/n （#14） monoclinic space group and its lattice parameters are a = 1.4141（6） nm, b = 1.0708（3） nm, c =2.2344（4） nm, β =952.4（2）°, and Gd（bfa）3· 2H2O crystallizes in P 212121 orthorhombic space group and its lattice parameters were a = 1.322 （1） nm, b = 2.295 （1） nm, c = 1. 0786（8） nm. In the meantime, the authors had finished a systematic investigation on the ^155Gd Mossbauer isomer shift （δ） of various Gd（Ⅲ） metal complexes having a different coordination number （C.N.） and different ratios coordinating oxygen to nitrogen. A tendency for the 6 value to decrease with an increase in the C.N, and the number of the nitrogen atom coordinating to Gd was confirmed. This indicated that the Gd-O and/or Gd-N bond in the investigated Gd（Ⅲ） metal complexes had a small covalent contribution, which was possible to be deduced from the O and/or N atoms of the lisands donating electrons to 6s, 5d, and 4f orbitals of Gd.展开更多
A novel one-dimensional chain-like coordination polymer constructed from 3-nitrobenzene- 1,2-dicarboxylic acid, [Cd2（C8H3NO6）2（H2O）4]n·2nH2O, has been synthesized and its structure was determined by X-ray cry...A novel one-dimensional chain-like coordination polymer constructed from 3-nitrobenzene- 1,2-dicarboxylic acid, [Cd2（C8H3NO6）2（H2O）4]n·2nH2O, has been synthesized and its structure was determined by X-ray crystallography method. The crystal belongs to monoclinic, space group P21/c with a = 6.1252（8）, b = 20.706（3）, c = 8.8067（11）A, β = 95.608（2）^o, V = 1111.6（2）A^3, Mr = 751.12, De= 2.244 g/cm^3, F（000） = 736,μ = 2.011 mm^-1, Z= 2, the final R = 0.0262 and wR = 0.0692 for 2338 observed reflections with I 〉 2a（I）. The structure of the title compound presents a 1-D chain-like structure constructed by dimer units, [Cd2（C8H3NO6）2（H2O）4]n, through two carboxylate oxygen atoms. The fluorescence of the title compound has been also discussed in this paper.展开更多
Cryo-electron microscopy makes use of transmission electron microscopy to image vitrified biological samples and reconstruct their three-dimensional structures from two-dimensional projections via computational approa...Cryo-electron microscopy makes use of transmission electron microscopy to image vitrified biological samples and reconstruct their three-dimensional structures from two-dimensional projections via computational approaches. After over40 years of development, this technique is now reaching its zenith and reforming the research paradigm of modern structural biology. It has been gradually taking over X-ray crystallography as the mainstream method. In this review, we briefly introduce the history of cryo-EM, recent technical development and its potential power to reveal dynamic structures. The technical barriers and possible approaches to tackle the upcoming challenges are discussed.展开更多
The title compound, [Mn2·（dinitrobenzoic acid）4·（1,10-phen）2]n, has a linear chain structure containing binuclear [Mn2·（dinitrobenzoic acid）4（1,10-phen）2] repeat units. It crystallizes in the tr...The title compound, [Mn2·（dinitrobenzoic acid）4·（1,10-phen）2]n, has a linear chain structure containing binuclear [Mn2·（dinitrobenzoic acid）4（1,10-phen）2] repeat units. It crystallizes in the triclinic system, space group Pi with a = 7.9261（8）, b = 12.1329（15）, c = 14.847（2）A, α = 103.845（5）, β = 101.424（5）, γ = 92.618（4）°, Mr= 657.37, V = 1352.3（2）A^3, Z = 2, De= 1.614 g/cm^3, F（000） = 666,μ = 0.567 mm^-1, the final R = 0.0407 and wR = 0.1015 for 4081 observed reflections with I 〉 2σ（I）. The Mn atom is six-coordinated by two N and four O atoms, forming a slightly distorted octahedral geometry. All Mn-O and Mn-N bond distances range from 2.093（2） to 2.310（2）A. Two adjacent octahdral units are bridged together by two pairs of bi-monodentate carboxyl groups of different dinitrobenzoic acids to form an eight-membered ring with chair-typed configuration, thus generating a one-dimensional chain along the a axis.展开更多
3 D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3 D printing was developed in the 1980 s and ...3 D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3 D printing was developed in the 1980 s and the technology has found widespread industrial applications for production from automotive parts to machine tools,its application in pharmaceutical area is still limited. However,the potential of 3 D printing in the pharmaceutical industry is now being recognized. The ability of 3 D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes,sizes and textures that are difficult to produce using traditional techniques. However,there are various challenges associated with the proper application of3 D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review,an overview is provided on the various 3 D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.展开更多
Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） ...Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.展开更多
文摘A new type of implantable drug delivery devices （ DDD ） with complicated architectures were fubricated by three-dimensional printing technique, employing levofloxacin （LVFX） as a model drug. Processing parameters were optimized in riew of the layer thickness, spucing between printed lines, flow rate of liquid binder and the fast axis speed. The prepared DDD prototype consists of a double-layer structure, of which the upper region is a reservoir system and the lower region is a matrix one. The in vitro release test revealed that LVFX was released in a dual-puse pattern. This DDD may present a new strategy for the prophylaxis and treatment of diseases such as bone infection in the near future.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11047022,11204045,and 11464004)the Tracking Key Program of Social Development of Guizhou Province,China(Grant Nos.SY20123089 and SZ20113069)+2 种基金the General Financial Grant from the China Postdoctoral Science Foundation(Grant No.2014M562341)the Research Foundation for Young University Teachers from Guizhou University(Grant No.201311)the College Innovation Talent Team of Guizhou Province,China(Grant No.(2014)32)
文摘We present an extended analytical model including the depletion effect and the dimension of ligand-receptor complex, aiming to elucidate their influences on endocytosis of spherocylindrical nanoparticles （NPs）. It is found that the dimension of ligand-receptor complex （δ） and the depletion effect interrelatedly govern the optimal conditions of NP endocytosis. The endocytosis phase diagram constructed in the space of NP radius and relative aspect ratio indicates that the endocytosis of NP is enhanced evidently by reducing the optimal radius and the threshold radius of endocytosed NP. Meanwhile, through thermodynamic and kinetic analysis of the diffusion of receptors, the dependence of diffusion length on depletion effect and the dimension of ligand-receptor complex can be identified in great detail. For small aspect ratio, diffusion length decreases with increasing concentration c of small bioparticles in cellular environment. Endocytosis speed corresponding to large radius R and high concentration c of small bioparticles strongly depends on the increasing （2r-δ）. These results may show some highlights into the conscious design of NPs for diagnostic agents and therapeutic drug delivery applications.
基金This project is supported by the Natural Science Foundation of Education Bureau of Liaoning Province,China.
文摘Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution and characterized by X-ray diffraction. 1 crystallizes in the monoclinic space, group P21/n, a = 17.341（6）A, b = 6.744（2）A, c = 34.555（12）A, β = 100.493（6）°, V = 3974（2） A^3, Z = 4. Each copper（H） ion has a distorted octahedral coordination geometry. Nitrate anion adopts the unusual coordination mode linking two adjacent copper（H） ions to form a one-dimensional coordination polymer and these chains are further linked by noncovalent interactions.
基金This work was supported by the National Natural Science Foundation of China (No. 50572040)
文摘The title complex Mn（H2O）2（HNic）2 （C22H12MnN2O8, Mr = 367.18） crystallizes in monoclinic, space group P21/c with a = 7.5735（8）, b = 12.5295（13）, c = 7.6466（8）A.β = 101.2790（10）°, Z = 2, V= 711.59（13） A^3, D, = 1.714 g/cm^3,μ（MoKa） = 0.974 mm^-1, F（000） = 374, R1 （1255 observed reflections （Ⅰ 〉 2σ（Ⅰ）） = 0.0250） and wR2 = 0.0662 （all data）. In this paper, we report the complexation of Mn（Ⅱ） by the bidentate ligand 2-hydroxynicotinic acid （HNic）. In the crystal the Mn（Ⅱ） ion exhibits a deformed octahedron structure. The title complex Mn（H2O）2（HNic）2 has a three-dimensional （3D） network structure extended by hydrogen bonds, which are formed by two typical eight-membered hydrogen-bonded rings.
文摘This paper uses the concept of algorithmic efficiency to present a unified theory of intelligence. Intelligence is defined informally, formally, and computationally. We introduce the concept of dimensional complexity in algorithmic efficiency and deduce that an optimally efficient algorithm has zero time complexity, zero space complexity, and an infinite dimensional complexity. This algorithm is used to generate the number line.
文摘The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- .
基金Project supported by the Grants-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan andin Part by the Inter-University Joint Research Program for the Common Use of JAERI (Japan Atomic Energy Research Institute)Facilities
文摘Some functional lanthanide metal complexes, such as acetylacetonato complexes, ethylenediaminetetraacetato complexes, were successfully applied for diagnostic technique. The authors are interested in investigating the structure and bonding in lanthanide and actinide metal complexes using 166Er, t55Gd, and 237Np Mtissbauer spectroscopies in connection with single-crystal and/or powder X-ray diffraction, making clear the differences on their structures as well as the differences in the participation of 4f and 5f orbitals in the chemical bonds. In this article, the crystal structures of two novel Gd（Ⅲ） acetylacetonato complexes, Gd（pta）3 · 2H2O （pta = 1,1,1 -trifluoro-5,5-dimethy 1-2,4-hexanedione） and Gd（bfa）3 · 2H2O （bfa = 1, 1, 1 -trifluoro-4-phenyl-2-4-butanedione） were reported. Though both of them were dihydrate and had distorted square antiprismatical structure, Gd（pta）3 · 2H2O crystallizes in the P 2 1/n （#14） monoclinic space group and its lattice parameters are a = 1.4141（6） nm, b = 1.0708（3） nm, c =2.2344（4） nm, β =952.4（2）°, and Gd（bfa）3· 2H2O crystallizes in P 212121 orthorhombic space group and its lattice parameters were a = 1.322 （1） nm, b = 2.295 （1） nm, c = 1. 0786（8） nm. In the meantime, the authors had finished a systematic investigation on the ^155Gd Mossbauer isomer shift （δ） of various Gd（Ⅲ） metal complexes having a different coordination number （C.N.） and different ratios coordinating oxygen to nitrogen. A tendency for the 6 value to decrease with an increase in the C.N, and the number of the nitrogen atom coordinating to Gd was confirmed. This indicated that the Gd-O and/or Gd-N bond in the investigated Gd（Ⅲ） metal complexes had a small covalent contribution, which was possible to be deduced from the O and/or N atoms of the lisands donating electrons to 6s, 5d, and 4f orbitals of Gd.
基金Supported by the Project of Fujian Science & Technology Committee (2006F5067)National Natural Science Foundations of China(20705031)
文摘A novel one-dimensional chain-like coordination polymer constructed from 3-nitrobenzene- 1,2-dicarboxylic acid, [Cd2（C8H3NO6）2（H2O）4]n·2nH2O, has been synthesized and its structure was determined by X-ray crystallography method. The crystal belongs to monoclinic, space group P21/c with a = 6.1252（8）, b = 20.706（3）, c = 8.8067（11）A, β = 95.608（2）^o, V = 1111.6（2）A^3, Mr = 751.12, De= 2.244 g/cm^3, F（000） = 736,μ = 2.011 mm^-1, Z= 2, the final R = 0.0262 and wR = 0.0692 for 2338 observed reflections with I 〉 2a（I）. The structure of the title compound presents a 1-D chain-like structure constructed by dimer units, [Cd2（C8H3NO6）2（H2O）4]n, through two carboxylate oxygen atoms. The fluorescence of the title compound has been also discussed in this paper.
文摘Cryo-electron microscopy makes use of transmission electron microscopy to image vitrified biological samples and reconstruct their three-dimensional structures from two-dimensional projections via computational approaches. After over40 years of development, this technique is now reaching its zenith and reforming the research paradigm of modern structural biology. It has been gradually taking over X-ray crystallography as the mainstream method. In this review, we briefly introduce the history of cryo-EM, recent technical development and its potential power to reveal dynamic structures. The technical barriers and possible approaches to tackle the upcoming challenges are discussed.
基金This work was financially supported by the NNSF of China (20472085)
文摘The title compound, [Mn2·（dinitrobenzoic acid）4·（1,10-phen）2]n, has a linear chain structure containing binuclear [Mn2·（dinitrobenzoic acid）4（1,10-phen）2] repeat units. It crystallizes in the triclinic system, space group Pi with a = 7.9261（8）, b = 12.1329（15）, c = 14.847（2）A, α = 103.845（5）, β = 101.424（5）, γ = 92.618（4）°, Mr= 657.37, V = 1352.3（2）A^3, Z = 2, De= 1.614 g/cm^3, F（000） = 666,μ = 0.567 mm^-1, the final R = 0.0407 and wR = 0.1015 for 4081 observed reflections with I 〉 2σ（I）. The Mn atom is six-coordinated by two N and four O atoms, forming a slightly distorted octahedral geometry. All Mn-O and Mn-N bond distances range from 2.093（2） to 2.310（2）A. Two adjacent octahdral units are bridged together by two pairs of bi-monodentate carboxyl groups of different dinitrobenzoic acids to form an eight-membered ring with chair-typed configuration, thus generating a one-dimensional chain along the a axis.
基金supported by Keimyung University Research Grant of 2017
文摘3 D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3 D printing was developed in the 1980 s and the technology has found widespread industrial applications for production from automotive parts to machine tools,its application in pharmaceutical area is still limited. However,the potential of 3 D printing in the pharmaceutical industry is now being recognized. The ability of 3 D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes,sizes and textures that are difficult to produce using traditional techniques. However,there are various challenges associated with the proper application of3 D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review,an overview is provided on the various 3 D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.
基金funded by the National Natural Science Foundation of China(Grant No.41172126)the State Key Laboratory of Petroleum Resources and Prospecting(PRP/indep-2-1402)
文摘Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.
