18 research outputs found
Primary familial brain calcification presenting with parkinsonism and motor complications caused by a novel SLC20A2 variant: a case report
Primary familial brain calcification (PFBC), also known as Fahr’s disease, is a central nervous system calcium deposition disorder with symmetrical basal ganglia calcification. Most PFBC cases are caused by SLC20A2 gene variant. We report a Chinese female patient with PFBC and dopamine-responsive parkinsonism who had motor fluctuations and dyskinesia and recovered effectively after symptomatic medication adjustment. A novel heterozygous missense variant was found by whole-exome sequencing and proven harmful by family validation and genetic analysis. This example expands the phenotype of SLC20A2-associated PFBC patients and shows the clinical efficacy of dopaminergic replacement treatment
Density Functional Theory Study of Selective Deacylation of Aromatic Acetate in the Presence of Aliphatic Acetate under Ammonium Acetate Mediated Conditions
Aromatic
acetates can be selectively deprotected in the presence
of aliphatic acetates under ammonium acetate mediated condition. B3LYP/6-31++G**
level of theory was demonstrated to be successfully used to model
the relative reaction rates for deacylation reactions for aliphatic
and aromatic ester systems. On the basis of the mechanistic studies,
acetate anion is most likely to be the active catalyst for the ester
deacylation reactions under ammonium acetate mediated condition
Establishing Reference Intervals for Normal Fetal Lung Biological Parameters at 21–40 Weeks of Gestation in the Chinese Population: A Cross-Sectional Study
(1) Background: There is no reliable way to assess antenatal fetal pulmonary hypoplasia; however, the biological parameters of the fetal lung can help in evaluating fetal lung development. This study aimed to establish the reference intervals for normal fetal lung biological parameters at 21–40 weeks among the Chinese population. (2) Methods: This was a cross-sectional study of Chinese groups, and included a total of 1388 normal single pregnant women at 21–40 weeks’ gestation. We selected 2134 images of a standard four-chamber view (4CV). ImageJ software (Release 2.14.0) was used to measure the left and right lung areas using a manual tracing method; the elliptic function key was used to measure the fetal thoracic circumference (TC), thoracic area (TA), head circumference (HC), heart area (HA), and abdominal circumference (AC). Based on the above measurements, the following parameters were calculated: lung area to head circumference ratio (LHR), total lung area (TLA), TLA/Weight (mm2/g), cardiothoracic ratio (CTR), lung–thoracic area ratio (TLA/TA), lung–heart area ratio (TLA/HA), TC/AC, and TC/HC. (3) Results: The left and right lung areas and LHRs positively correlated with gestational age (R2 = 0.85, 0.88, 0.66, 0.71, p 2/g) was weakly correlated with gestational age, while CTR, TLA/TA, TLA/HA, TC/AC, and TC/HC had no significant correlation with gestational age. There was no statistically significant difference in fetal lung parameters between different genders of newborns, p > 0.05. (4) Conclusions: Our study establishes the reference intervals for normal Chinese fetal lung biological parameters at 21–40 weeks. Moreover, the reference intervals apply to fetuses of different genders. This paper can provide a reference for the prenatal non-invasive assessment of fetal pulmonary hypoplasia
Allosteric regulation of the conformational dynamics of a cavitand receptor
Inspired by allostery in nature, we synthesized cavitand 1 and investigated regulation of its conformational dynamics. Quantitative H-1 NMR studies have revealed that the rate of the conformational isomerization of 1 can be modulated using the external addition of acid. As 1 maintains its vase-like conformation in an acidic environment, ample opportunities for controlling the kinetics of molecular recognition, and thus reactivity, in this and related receptors have arisen
Extensive Sampling Provides New Insights into Phylogenetic Relationships between Wild and Domesticated <i>Zanthoxylum</i> Species in China
Zanthoxylum, belonging to the Rutaceae family, is widely distributed in tropical and subtropical regions. The genus has high economic value as spices, oils, medicinal plants, and culinary applications. Zanthoxylum has a long history of domestication and cultivation in China. However, the phylogenetic relationships and origin of wild and cultivated Zanthoxylum species in China remain largely unknown. Moreover, there is still no clear molecular phylogenetic system for Zanthoxylum species. Herein, 373 Zanthoxylum samples were collected from all presently known provenances of Zanthoxylum in China. In this study, four chloroplast DNA (cpDNA) markers (matK, ndhH, psbB, rbcL) were used to comprehensively analyze the genetic diversity, relatedness, and geographical origin of Chinese Zanthoxylum species. The results were as follows: (1) The aligned length of the four pairs of cpDNA sequences was 3836 bp, and 68 haplotypes were identified according to 219 variable polymorphic sites, including 90 singleton variable sites, 129 parsimony informative sites, 3 Indels (insertions and deletions). (2) Phylogenetic tree and haplotype network strongly supported the division of Zanthoxylum species consistent with the taxonomic recognition of five species: Z. bungeanum, Z. piasezkii, Z. piperitum, Z. armatum, and Z. micranthum. (3) Divergence time estimation suggested that Zanthoxylum genus originated from the Late Eocene, and most Zanthoxylum species diverged after the Middle Miocene. (4) Haplotype 16 (H16) was at the bottom of the phylogenetic tree, had higher haplotype diversity (Hd) and nucleotide polymorphism (Pi) than other haplotypes, and was located in the center of the network figure. Therefore, we deduced that the cultivated Zanthoxylum species may originate in Zhouqu County, Gansu Province, China. Meanwhile, our research provided a scientific basis for the identification and breeding programs of Chinese Zanthoxylum species
Rationally designed ultrathin Ni(OH)2/titanate nanosheet heterostructure for photocatalytic CO2 reduction
Dye-sensitized photocatalysis has been extensively studied for photocatalytic solar energy conversion due to the advantage in capturing long-wavelength photons with a high absorption coefficient. The rational integration of photosensitizer with semiconductor and cocatalyst to collaboratively operate in one system is highly desired. Here, we fabricate a Ni(OH)2-loaded titanate nanosheet (Ni(OH)2/H2Ti6O13) composite for high-performance dye-sensitized photocatalytic CO2 reduction. The ultrathin H2Ti6O13 nanosheets with negative surface charge provide an excellent support to anchor the dye photosensitizer, while the loaded Ni(OH)2 serves as an adsorbent of CO2 and electron sink of photoelectrons. As such, the photoelectrons derived from the [Ru(bpy)3]Cl2 sensitizer can be targeted transfer to the Ni(OH)2 active sites via the H2Ti6O13 nanosheets linker. A high CO production rate of 1801 μmol g-1 h-1 is obtained over the optimal Ni(OH)2/H2Ti6O13, while the pure H2Ti6O13 shows significantly lower CO2 reduction performance. The work is anticipated to trigger more research attention on the rational design and synthesis of earth-abundant transition metal-based cocatalysts decorated on ultrathin 2D platforms for artificially photocatalytic CO2 reduction
Supramolecular catalysis at work: Diastereoselective synthesis of a molecular bowl with dynamic inner space
[GRAPHICS] The supramolecular assistance to Pd(0)/Cu(I)-catalyzed cyclotrimerization of stannylated norbornene 7 has been investigated to give molecular bowl 1(syn) in a stereoselective fashion. Following a divergent strategy, racemic norbornene 7 was synthesized in satisfactory yield. Self-coupling, promoted by Pd(0)/Cu(I) catalysis acting in synergy with CsF, yielded molecular bowl 1(syn) in a moderate 30% yield. The reaction diastereoselectivity is affected by the concentration of Cu(I) and Cs+: increasing quantities of the cations enhanced the synlanti ratio of the isolated cyclotrimer from statistical (1:3) to a more desirable (4.5:1) ratio, in favor of the molecular bowl 1(syn) H-1 NMR spectroscopic studies suggested the coordinating affinity of 1(syn) toward transition metals Cu(I), Ag(I), and Au(I), to account for the observed templation effect. In particular, the tridentate 1(syn) has been shown to bind to one Ag(I) cation in the assembly process that is driven with enthalpy (Delta H-0 = - 19 +/- 2 kcal/mol, Delta S-0 = -45 eu). The complete coordination was not cooperative, and was hypothesized to be impeded with the adverse entropy. Accordingly, density functional theory (BP86) calculations of 1(syn) and its mono-, bis-, and tris-Ag(I) complexes suggested that the coordination of one to three silver cations is highly exothermic. The calculations also revealed that the bowl constriction is necessary for the aromatic arms to become preorganized and bind to a silver cation(s) (Delta E approximate to 8 kcal/mol). Ultimately, Ag(I) has been shown to assist the diastereoselective formation of lending support to the notion, of template-directed synthesis
Reactivity of molecular oxygen with ethoxycarbonyl derivatives of tetrathiatriarylmethyl radicals
[Image: see text] Tetrathiatriarylmethyl (TAM) radicals are commonly used as oximetry probes for electron paramagnetic resonance imaging (EPRI) applications. In this study, the electronic properties and the thermodynamic preferences for O(2) addition to various TAM-type triarylmethyl (trityl) radicals were theoretically investigated. The radicals' stability in the presence of O(2) and biological milieu were also experimentally assessed using EPR spectroscopy. Results show that H substitution on the aromatic ring affects the trityl radical's stability (tricarboxylate salt 1-CO(2)Na > triester 1-CO(2)Et > diester 2-CO(2)Et > monoester 3-CO(2)Et) and may lead to substitution reactions in cellular systems. We propose that this degradation process involves an arylperoxyl radical which can further decompose to alcohol or quinone products. This study demonstrates how computational chemistry can be used as a tool to rationalize radical stability in the redox environment of biological systems and aid in the future design of more biostable trityl radicals
Silver(I) mediated folding of a molecular basket
We have investigated Ag(I) mediated folding of a tridentate compound, containing three pyridine flaps tethered to a semirigid scaffold, into a molecular basket, using both experimental and theoretical methods. The basket formation has been shown to be highly favorable in organic media (Delta G degrees = -7.2 kcal/mol), with the assembly process allowing for another ligand to bind preferentially on the outer side