Image_1_Altered gray matter structural covariance networks in drug-naïve and treated early HIV-infected individuals.PDF

BackgroundWhile regional brain structure and function alterations in HIV-infected individuals have been reported, knowledge about the topological organization in gray matter networks is limited. This research aims to investigate the effects of early HIV infection and combination antiretroviral therapy (cART) on gray matter structural covariance networks (SCNs) by employing graph theoretical analysis.MethodsSixty-five adult HIV+ individuals (25–50 years old), including 34 with cART (HIV+/cART+) and 31 medication-naïve (HIV+/cART–), and 35 demographically matched healthy controls (HCs) underwent high-resolution T1-weighted images. A sliding-window method was employed to create “age bins,” and SCNs (based on cortical thickness) were constructed for each bin by calculating Pearson's correlation coefficients. The group differences of network indices, including the mean nodal path length (Nlp), betweenness centrality (Bc), number of modules, modularity, global efficiency, local efficiency, and small-worldness, were evaluated by ANOVA and post-hoc tests employing the network-based statistics method.ResultsRelative to HCs, less efficiency in terms of information transfer in the parietal and occipital lobe (decreased Bc) and a compensated increase in the frontal lobe (decreased Nlp) were exhibited in both HIV+/cART+ and HIV+/cART– individuals (P ConclusionEarly HIV+ individuals exhibited a decrease in the efficiency of information transmission in sensory regions and a compensatory increase in the frontal lobe. HIV+/cART+ showed a less specialized regional segregation function, but a stronger global integration function in the network.</p

Crystal Structures of Two New Gold–Copper Bimetallic Nanoclusters: Cu_<i>x</i>Au_{25–<i>x</i>}(PPh₃)₁₀(PhC₂H₄S)₅Cl₂²⁺ and Cu₃Au₃₄(PPh₃)₁₃(^tBuPhCH₂S)₆S₂³⁺

Herein, we report the synthesis and atomic structures of the cluster-assembled Cu_<i>x</i>­Au_{25–<i>x</i>}­(PPh₃)₁₀­(PhCH₂CH₂S)₅­Cl₂²⁺ and Cu₃­Au₃₄­(PPh₃)₁₃­(^tBuPhCH₂S)₆­S₂³⁺ nanoclusters (NCs). The atomic structures of both NCs were precisely determined by single-crystal X-ray crystallography. The Cu_<i>x</i>­Au_{25–<i>x</i>}­(PPh₃)₁₀­(PhC₂H₄S)₅­Cl₂²⁺ NC was assembled by two icosahedral M₁₃ via a vertex-sharing mode. The Cu atom partially occupies the top and waist sites and is monocoordinated with chlorine or thiol ligands. Meanwhile, the Cu₃­Au₃₄­(PPh₃)₁₃­(^tBuPhCH₂S)₆­S₂³⁺ NC can be described as three 13-atom icosahedra sharing three vertexes in a cyclic fashion. The three Cu atoms all occupy the internal positions of the cluster core. What is more important is that all three Cu atoms in Cu₃Au₃₄ are monocoordinated by the bare S atoms. The absorption spectra of the as-synthesized bimetallic NCs reveal that the additional metal doping and different cluster assemblies affect the electronic structure of the monometallic NCs

Crystal Structures of Two New Gold–Copper Bimetallic Nanoclusters: Cu_<i>x</i>Au_{25–<i>x</i>}(PPh₃)₁₀(PhC₂H₄S)₅Cl₂²⁺ and Cu₃Au₃₄(PPh₃)₁₃(^tBuPhCH₂S)₆S₂³⁺

Herein, we report the synthesis and atomic structures of the cluster-assembled Cu_<i>x</i>­Au_{25–<i>x</i>}­(PPh₃)₁₀­(PhCH₂CH₂S)₅­Cl₂²⁺ and Cu₃­Au₃₄­(PPh₃)₁₃­(^tBuPhCH₂S)₆­S₂³⁺ nanoclusters (NCs). The atomic structures of both NCs were precisely determined by single-crystal X-ray crystallography. The Cu_<i>x</i>­Au_{25–<i>x</i>}­(PPh₃)₁₀­(PhC₂H₄S)₅­Cl₂²⁺ NC was assembled by two icosahedral M₁₃ via a vertex-sharing mode. The Cu atom partially occupies the top and waist sites and is monocoordinated with chlorine or thiol ligands. Meanwhile, the Cu₃­Au₃₄­(PPh₃)₁₃­(^tBuPhCH₂S)₆­S₂³⁺ NC can be described as three 13-atom icosahedra sharing three vertexes in a cyclic fashion. The three Cu atoms all occupy the internal positions of the cluster core. What is more important is that all three Cu atoms in Cu₃Au₃₄ are monocoordinated by the bare S atoms. The absorption spectra of the as-synthesized bimetallic NCs reveal that the additional metal doping and different cluster assemblies affect the electronic structure of the monometallic NCs

Structure and Electronic Structure Evolution of Thiolate-Protected Gold Nanoclusters Containing Quasi Face-Centered-Cubic Kernels

A structure evolution map of face-centered cubic (fcc)-structured thiolate-ligand protected gold nanoclusters is outlined on the basis of total structure determination of a new 6e Au₂₁(SR)₁₅ (R = <i>tert</i>-butyl, <i>t</i>-Bu) cluster. The structural evolution map described some basic structural evolution patterns such as a triangle-Au₃ and tetrahedron-Au₄ associated gold-core evolution pattern and the periodic or symmetric growth of gold cores and ligand shells. According to the structural evolution map, a topological structure–electronic structure relationship is also proposed. The delocalized valence electronic properties of any fcc-structured gold clusters may be expressed as the linear combinations of the molecular orbitals of the fragment 2e units (Au₃⁺ and Au₄²⁺). The structural disciplines and topological structure–electronic structure relationships reported in this work laid a basis for understanding the structural evolution and electronic structure of fcc-structured thiolate-protected gold nanoclusters. Particularly, the established structural evolution map provides a tool to explore new magic-sized clusters and cluster structures. In this work, a new fcc-structured 4e Au₁₇(SR)₁₃ and a new isomer structure of the 8e Au₂₈(SR)₂₀ cluster were predicted. The medium-sized fcc-structured gold clusters locating in the size range from 52 to 92 gold atoms and even larger-sized gold clusters can be also explored from the structural regularities described in the map

Structure and Electronic Structure Evolution of Thiolate-Protected Gold Nanoclusters Containing Quasi Face-Centered-Cubic Kernels

A structure evolution map of face-centered cubic (fcc)-structured thiolate-ligand protected gold nanoclusters is outlined on the basis of total structure determination of a new 6e Au₂₁(SR)₁₅ (R = <i>tert</i>-butyl, <i>t</i>-Bu) cluster. The structural evolution map described some basic structural evolution patterns such as a triangle-Au₃ and tetrahedron-Au₄ associated gold-core evolution pattern and the periodic or symmetric growth of gold cores and ligand shells. According to the structural evolution map, a topological structure–electronic structure relationship is also proposed. The delocalized valence electronic properties of any fcc-structured gold clusters may be expressed as the linear combinations of the molecular orbitals of the fragment 2e units (Au₃⁺ and Au₄²⁺). The structural disciplines and topological structure–electronic structure relationships reported in this work laid a basis for understanding the structural evolution and electronic structure of fcc-structured thiolate-protected gold nanoclusters. Particularly, the established structural evolution map provides a tool to explore new magic-sized clusters and cluster structures. In this work, a new fcc-structured 4e Au₁₇(SR)₁₃ and a new isomer structure of the 8e Au₂₈(SR)₂₀ cluster were predicted. The medium-sized fcc-structured gold clusters locating in the size range from 52 to 92 gold atoms and even larger-sized gold clusters can be also explored from the structural regularities described in the map

Structure and Electronic Structure Evolution of Thiolate-Protected Gold Nanoclusters Containing Quasi Face-Centered-Cubic Kernels

A structure evolution map of face-centered cubic (fcc)-structured thiolate-ligand protected gold nanoclusters is outlined on the basis of total structure determination of a new 6e Au₂₁(SR)₁₅ (R = <i>tert</i>-butyl, <i>t</i>-Bu) cluster. The structural evolution map described some basic structural evolution patterns such as a triangle-Au₃ and tetrahedron-Au₄ associated gold-core evolution pattern and the periodic or symmetric growth of gold cores and ligand shells. According to the structural evolution map, a topological structure–electronic structure relationship is also proposed. The delocalized valence electronic properties of any fcc-structured gold clusters may be expressed as the linear combinations of the molecular orbitals of the fragment 2e units (Au₃⁺ and Au₄²⁺). The structural disciplines and topological structure–electronic structure relationships reported in this work laid a basis for understanding the structural evolution and electronic structure of fcc-structured thiolate-protected gold nanoclusters. Particularly, the established structural evolution map provides a tool to explore new magic-sized clusters and cluster structures. In this work, a new fcc-structured 4e Au₁₇(SR)₁₃ and a new isomer structure of the 8e Au₂₈(SR)₂₀ cluster were predicted. The medium-sized fcc-structured gold clusters locating in the size range from 52 to 92 gold atoms and even larger-sized gold clusters can be also explored from the structural regularities described in the map