185 research outputs found
A double-walled triangular metal-organic macrocycle based on a [Cu-2(COO)(4)] square paddle-wheel secondary building unit
A metal-organic macrocycle (MOM), [(Cu-2)(3)L-6(DMF)(2)(H2O)(4)], was prepared using a long and "pseudo-rigid" dicarboxylic acid, 1,4-bis(3-carboxylphenylethynyl) benzene (H2L), with some rotational flexibility, where the MOM has a double-walled triangular geometry with three Cu paddle-wheel secondary building units (SBUs) doubly connected by the ligands in a cis-conformation.close8
A two-fold interpenetrated (3,6)-connected metal-organic framework with rutile topology showing a large solvent cavity
A two-fold interpenetrated metal-organic framework (MOF), [(Zn(4)O)(2)L(4)(DMF)(2)(H(2)O)(3)], was prepared using the tritopic ligand 4,4',4 ''-[1,3,5-benzenetriyltris(carbonylimino)]trisbenzoic acid (H(3)L) and zinc nitrate. The MOF, based on the hexatopic tetranuclear Zn(4)O(COO)(6) secondary building unit, has a (3,6)-connected network with an rtl topology and a large solvent cavity.close302
Preparation of Edible Corn Starch Phosphate with Highly Reactive Sodium Tripolyphosphate in the Absence of Catalyst
Purpose: To prepare edible corn starch phosphate under optimized experimental conditions.Methods: Edible corn starch phosphate was prepared via the reaction of starch with active sodium tripolyphosphate. Reaction efficiency and viscosity were used as indices to optimize experimental conditions. Freeze-thaw stability and transparency of starch phosphate and native starch were comparatively studied.Results: Starch phosphate with optimal combined phosphate content (0.39 %) was obtained under optimized conditions: reaction duration, 90 min; temperature, 160 oC; pH, 5.0; and phosphate, 1.5 g. Starch phosphate with optimal viscosity (230 cp) was obtained under different conditions: reaction duration, 120 min; temperature, 140 oC; pH, 6.0; and phosphate, 1.5 g. Significant differences (p < 0.05) were observed in syneresis and paste transparency of starch phosphate and native starch.Conclusion: Edible corn starch phosphate has been successfully prepared under optimized experimental conditions whose freeze-thaw stability and paste transparency has obvious improvement compared with native starch.Keywords: Starch phosphate, Combined phosphate, Sodium tripolyphosphate, Syneresis, Paste efficienc
Entropically driven self-assembly of a strained hexanuclear indium metal-organic macrocycle and its behavior in solution
The self-assembly of a polyprotic pentadentate ligand, N-cyclopentanoylaminobenzoylhydrazide (H4L4), and an In(III) nitrate hydrate in methanol led to a strained hexanuclear indium metal-organic macrocycle (In-MOM), [In(III)(6)(H2L4)(6)(NO3)(x)(solvent)(6-x)](NO3)(6-x) (where, the solvent is either methanol or a water molecule and x is the number of the nitrate anions ligated). The ligand in the doubly deprotonated state serves as an unsymmetric linear ditopic donor and the alternating indium ions in two different chelation modes serve as two different bent ditopic metal acceptors, which led to a D-3-symmetric hexanuclear In-MOM. Although the hexanuclear In-MOM is enthalpically unfavorable because of the ring strain, the combination of the soft coordination characteristic of the indium ion and the slight ligand deformation from the conjugated planar conformation allows the formation of the entropically favored hexanuclear In-MOM rather than the enthalpically favored octanuclear In-MOM. While the hexanuclear In-MOM is stable in acetonitrile, it partially dissociates into its components in dimethylsulfoxide, and then slowly reaches a new equilibrium state with several different indium species yet to be identified in addition to the free ligand.close4
Practical Quantum Simulation of Non-Hermitian Dynamics
Non-Hermitian quantum systems have recently attracted considerable attentions
due to their exotic properties. Though many experimental realizations of
non-Hermitian systems have been reported, the non-Hermiticity usually resorts
to the hard-to-control environments. An alternative approach is to use quantum
simulation with the closed system, whereas how to simulate general
non-Hermitian Hamiltonian dynamics remains a great challenge. To tackle this
problem, we propose a protocol by combining a dilation method with the
variational quantum algorithm. The dilation method is used to transform a
non-Hermitian Hamiltonian into a Hermitian one through an exquisite quantum
circuit, while the variational quantum algorithm is for efficiently
approximating the complex entangled gates in this circuit. As a demonstration,
we apply our protocol to simulate the dynamics of an Ising chain with nonlocal
non-Hermitian perturbations, which is an important model to study quantum phase
transition at nonzero temperatures. The numerical simulation results are highly
consistent with the theoretical predictions, revealing the effectiveness of our
protocol. The presented protocol paves the way for practically simulating
general non-Hermitian dynamics in the multi-qubit case.Comment: 9 pages, 5 figure
An unprecedented twofold interpenetrated layered metal-organic framework with a MoS2-H topology
An unprecedented twofold interpenetrated layered metal-organic framework with a two-dimensional 3,6-connected net topology has been prepared using a tricarboxylic acid as a 3-connected node and a Zn4O(COO)(6) cluster as a 6-connected node, where the ligand flexibility and the combination of pi-pi stacking and hydrogen bonding interactions render the 6-connected node into a topological trigonal prismatic node.close10
Contextualizing the Revised Patient Perception of Patient-Centeredness (Pppc-R) Scale in Primary Healthcare Settings: a Validity and Reliability Evaluation Study
BACKGROUND: An English version of the Patient Perception of Patient-Centeredness (PPPC) scale was recently revised, and it is necessary to test this instrument in different primary care populations.
AIM: This study aimed to assess the validity and reliability of a Chinese version of the PPPC scale.
DESIGN: A mixed method was used in this study. The Delphi method was used to collect qualitative and quantitative data to address the content validity of the PPPC scale by calculating the Content Validity Index, Content Validity Ratio, the adjusted Kappa, and the Item Impact Score. Confirmatory factor analysis (CFA) and exploratory factor analysis (EFA) were used to assess the construct validity of the PPPC scale through a cross-sectional survey. The internal consistency was also assessed.
SETTING/PARTICIPANTS: In the Delphi consultation, seven experts were consulted through a questionnaire sent by email. The cross-sectional survey interviewed 188 outpatients in Guangzhou city and 108 outpatients in Hohhot City from community health service centers or stations face-to-face.
RESULTS: The 21 items in the scale were relevant to their component. The Item-level Content Validity Index for each item was higher than 0.79, and the average Scale-level content validity index was 0.97 in each evaluation round. The initial proposed 4-factor CFA model did not fit adequately. Still, we found a 3-factor solution based on our EFA model and the validation via the CFA model (model fit: [Formula: see text], P \u3c 0.001, RMSEA = 0.044, CFI = 0.981; factor loadings: 0.553 to 0.888). Cronbach\u27s α also indicated good internal consistency reliability: The overall Cronbach\u27s α was 0.922, and the Cronbach\u27s α for each factor was 0.851, 0.872, and 0.717, respectively.
CONCLUSIONS: The Chinese version of the PPPC scale provides a valuable tool for evaluating patient-centered medical service quality
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