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1.
Osteoporos Int ; 35(9): 1645-1659, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38953947

RESUMEN

Our study showed that B vitamins did not have significant effect on fracture incidence, bone mineral density, and bone turnover markers. However, the research data of B vitamins on bone mineral density and bone turnover markers are limited, and more clinical trials are needed to draw sufficient conclusions. PURPOSE: The objective of this study was to identify the efficacy of B vitamin (VB) (folate, B6, and B12) supplements on fracture incidence, bone mineral density (BMD), and bone turnover markers (BTMs). METHODS: A comprehensive search was performed in PubMed, MEDLINE, EMBASE, Cochrane databases, and ClinicalTrials.gov up to September 4, 2023. The risk of bias was assessed according to Cochrane Handbook and the quality of evidence was assessed according to the GRADE system. We used trial sequential analysis (TSA) to assess risk of random errors and Stata 14 to conduct sensitivity and publication bias analyses. RESULTS: Data from 14 RCTs with 34,700 patients were extracted and analyzed. The results showed that VBs did not significantly reduce the fracture incidence (RR, 1.06; 95% CI, 0.95 - 1.18; p = 0.33; I2 = 40%) and did not affect BMD in lumbar spine and femur neck. VBs had no significant effect on bone specific alkaline phase (a biomarker for bone formation), but could increase the serum carboxy-terminal peptide (a biomarker for bone resorption) (p = 0.009; I2 = 0%). The TSA showed the results of VBs on BMD and BTMs may not be enough to draw sufficient conclusions due to the small number of sample data included and needed to be demonstrated in more clinical trials. The inability of VBs to reduce fracture incidence has been verified by TSA as sufficient. Sensitivity analysis and publication bias assessment proved that our meta-analysis results were stable and reliable, with no significant publication bias. CONCLUSIONS: Available evidence from RCTs does not support VBs can effectively influence osteoporotic fracture risk, BMD, and BTMs. TRIAL REGISTRATION: PROSPERO registration number: CRD42023427508.


Asunto(s)
Densidad Ósea , Remodelación Ósea , Fracturas Osteoporóticas , Complejo Vitamínico B , Humanos , Biomarcadores/sangre , Densidad Ósea/fisiología , Densidad Ósea/efectos de los fármacos , Remodelación Ósea/fisiología , Remodelación Ósea/efectos de los fármacos , Suplementos Dietéticos , Ácido Fólico/uso terapéutico , Incidencia , Fracturas Osteoporóticas/prevención & control , Fracturas Osteoporóticas/epidemiología , Ensayos Clínicos Controlados Aleatorios como Asunto , Vitamina B 12/uso terapéutico , Vitamina B 12/sangre , Vitamina B 6/uso terapéutico , Complejo Vitamínico B/uso terapéutico
2.
Phys Rev Lett ; 132(22): 226003, 2024 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-38877959

RESUMEN

The nature of the anomalous metal state has been a major puzzle in condensed matter physics for more than three decades. Here, we report systematic investigation and modulation of the anomalous metal states in high-temperature interface superconductor FeSe films on SrTiO_{3} substrate. Remarkably, under zero magnetic field, the anomalous metal state persists up to 20 K in pristine FeSe films, an exceptionally high temperature standing out from previous observations. In stark contrast, for the FeSe films with nanohole arrays, the characteristic temperature of the anomalous metal state is considerably reduced. We demonstrate that the observed anomalous metal states originate from the quantum tunneling of vortices adjusted by the Ohmic dissipation. Our work offers a perspective for understanding the origin and modulation of the anomalous metal states in two-dimensional bosonic systems.

3.
J Am Chem Soc ; 144(30): 13806-13814, 2022 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-35816081

RESUMEN

Ferroelectric domains and domain walls are unique characteristics of ferroelectric materials. Among them, charged domain walls (CDWs) are a special kind of peculiar microstructure that highly improve conductivity, piezoelectricity, and photovoltaic efficiency. Thus, CDWs are believed to be the key to ferroelectrics' future application in fields of energy, sensing, information storage, and so forth. Studies on CDWs are one of the most attractive directions in conventional inorganic ferroelectric ceramics. However, in newly emerged molecular ferroelectrics, which have advantages such as lightweight, easy preparation, simple film fabrication, mechanical flexibility, and biocompatibility, CDWs are rarely observed due to the lack of free charges. In inorganic ferroelectrics, doping is a traditional method to induce free charges, but for molecular ferroelectrics fabricated by solution processes, doping usually causes phase separation or phase transition, which destabilizes or removes ferroelectricity. To realize stable CDWs in molecular systems, we designed and synthesized an n-type molecular ferroelectric, 1-adamantanammonium hydroiodate. In this compound, negative charges are induced by defects in the I- vacancy, and CDWs can be achieved. Nanometer-scale CDWs that are stable at temperatures as high as 373 K can be "written" precisely by an electrically biased metal tip. More importantly, this is the first time that the charge diffusion of CDWs at variable temperatures has been investigated in molecular ferroelectrics. This work provides a new design strategy for n-type molecular ferroelectrics and may shed light on their future applications in flexible electronics, microsensors, and so forth.

4.
Am J Hum Genet ; 105(5): 996-1004, 2019 11 07.
Artículo en Inglés | MEDLINE | ID: mdl-31587869

RESUMEN

Mechanically activated (MA) ion channels convert physical forces into electrical signals. Despite the importance of this function, the involvement of mechanosensitive ion channels in human disease is poorly understood. Here we report heterozygous missense mutations in the gene encoding the MA ion channel TMEM63A that result in an infantile disorder resembling a hypomyelinating leukodystrophy. Four unrelated individuals presented with congenital nystagmus, motor delay, and deficient myelination on serial scans in infancy, prompting the diagnosis of Pelizaeus-Merzbacher (like) disease. Genomic sequencing revealed that all four individuals carry heterozygous missense variants in the pore-forming domain of TMEM63A. These variants were confirmed to have arisen de novo in three of the four individuals. While the physiological role of TMEM63A is incompletely understood, it is highly expressed in oligodendrocytes and it has recently been shown to be a MA ion channel. Using patch clamp electrophysiology, we demonstrated that each of the modeled variants result in strongly attenuated stretch-activated currents when expressed in naive cells. Unexpectedly, the clinical evolution of all four individuals has been surprisingly favorable, with substantial improvements in neurological signs and developmental progression. In the three individuals with follow-up scans after 4 years of age, the myelin deficit had almost completely resolved. Our results suggest a previously unappreciated role for mechanosensitive ion channels in myelin development.


Asunto(s)
Canales Iónicos/genética , Proteínas de la Membrana/genética , Vaina de Mielina/genética , Enfermedad de Pelizaeus-Merzbacher/genética , Adolescente , Adulto , Preescolar , Femenino , Heterocigoto , Humanos , Masculino , Mutación Missense/genética , Oligodendroglía/metabolismo , Adulto Joven
5.
J Nanobiotechnology ; 20(1): 60, 2022 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-35109862

RESUMEN

The localization of invisible and impalpable small pulmonary nodules has become an important concern during surgery, since current widely used techniques for localization have a number of limitations, such as invasive features of hookwires and microcoils, and rapid diffusion after injection of indocyanine green (ICG). Lanthanide-based metal-organic frameworks (MOFs) have been proven as potential fluorescent agents because of their prominent luminescent characteristics, including large Stokes shifts, high quantum yields, long decay lifetimes, and undisturbed emissive energies. In addition, lanthanides, such as Eu, can efficiently absorb X-rays for CT imaging. In this study, we synthesized Eu-UiO-67-bpy (UiO = University of Oslo, bpy = 2,2'-bipyridyl) as a fluorescent dye with a gelatin-methacryloyl (GelMA) hydrogel as a liquid carrier. The prepared complex exhibits constant fluorescence emission owing to the luminescent characteristics of Eu and the stable structure of UiO-67-bpy with restricted fluorescence diffusion attributed to the photocured GelMA. Furthermore, the hydrogel provides stiffness to make the injection site tactile and improve the accuracy of localization and excision. Finally, our complex enables fluorescence-CT dual-modal imaging of the localization site.


Asunto(s)
Elementos de la Serie de los Lantanoides , Estructuras Metalorgánicas , Difusión , Gelatina/química , Hidrogeles/química
6.
J Nanobiotechnology ; 20(1): 259, 2022 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-35672708

RESUMEN

Patients with diabetic foot ulcers usually suffer from inefficient epithelisation and angiogenesis accompanied by chronic wound healing. Diabetic foot ulcers remain a major challenge in clinical medicine; however, traditional treatments are incapable of transdermal drug delivery, resulting in a low drug delivery rate. We report the development of Ti2C3 MXenes-integrated poly-γ-glutamic acid (γ-PGA) hydrogel microneedles to release asiaticoside (MN-MXenes-AS). Asiaticoside was loaded into PGA-MXenes hydrogel to facilitate cell proliferation while regulating angiogenesis. The characterisation and mechanical strength of the microneedles were investigated in vitro, and the wound-healing efficacy of the microneedles was confirmed in diabetic mice. MXenes significantly improved the mechanical strength of microneedles, while γ-PGA hydrogels provided a moist microenvironment for wound healing. Mice treated with MN-MXenes-AS demonstrated obvious improvements in wound healing process. We successfully fabricated an MXenes-integrated microneedle that possesses sufficient rigidity to penetrate the cuticle for subcutaneous drug delivery, thereby accelerating diabetic wound healing. We demonstrated that MN-MXenes-AS is effective in promoting growth both in vivo and in vitro. Collectively, our data show that MN-MXenes-AS accelerated the healing of diabetic foot ulcers, supporting the use of these microneedles in the treatment of chronic wounds.


Asunto(s)
Diabetes Mellitus Experimental , Pie Diabético , Animales , Diabetes Mellitus Experimental/tratamiento farmacológico , Pie Diabético/tratamiento farmacológico , Humanos , Hidrogeles , Ratones , Triterpenos , Cicatrización de Heridas
7.
Nano Lett ; 21(18): 7486-7494, 2021 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-34460267

RESUMEN

The metallic ground state in two-dimensional (2D) superconductors has attracted much attention but is still under intense scrutiny. Especially, the measurements in the ultralow temperature region are challenging for 2D superconductors due to the sensitivity to external perturbations. In this work, the resistance saturation induced by external noise, named as the "extrinsic anomalous metallic state", is observed in 2D transition metal dichalcogenide (TMD) superconductor 4Ha-TaSe2 nanodevices. However, with further decreasing temperature, credible evidence of the intrinsic anomalous metallic state is obtained by adequately filtering external radiation. Our work indicates that, at ultralow temperatures, the anomalous metallic state can be experimentally revealed as the quantum ground state in 2D crystalline TMD superconductors. Besides, Ising superconductivity revealed by ultrahigh in-plane critical field (Bc2∥) going beyond the Pauli paramagnetic limit (Bp) is detected in 4Ha-TaSe2, from the one-unit-cell device to the bulk situation, which might be due to the weak coupling between the TaSe2 submonolayers.

8.
J Hum Genet ; 66(8): 761-768, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33597727

RESUMEN

Hypomyelinating leukodystrophies (HLDs) are a rare group of disorders characterized by myelin deficit of the brain-based on MRI. Here, we studied 20 patients with unexplained HLD to uncover their genetic etiology through whole-exome sequencing (WES). Trio-based WES was performed for 20 unresolved HLDs families after genetic tests for the PLP1 duplication and a panel of 115 known leukodystrophy-related genes. Variants in both known genes that related to HLDs and promising candidate genes were analyzed. Minigene splicing assay was conducted to confirm the effect of splice region variant. All 20 patients were diagnosed with HLDs clinically based on myelin deficit on MRI and impaired motor ability. Through WES, in 11 of 20 trios, 15 causative variants were detected in seven genes TUBB4A, POLR1C, POLR3A, SOX10, TMEM106B, DEGS1, and TMEM63A. The last three genes have just been discovered. Of 15 variants, six were novel. Using minigene splicing assay, splice variant POLR3A c.1770 + 5 G > C was proved to disrupt the normal splicing of intron 13 and led to a premature stop codon at position 618 (p.(P591Vfs*28)). Our analysis determined the molecular diagnosis of 11 HLDs patients. It emphasizes the heterogenicity of HLDs, the diagnostic power of trio-based WES for HLDs. Comprehensive analysis including a focus on candidate genes helps to discover novel disease-causing genes, determine the diagnosis for the first time, and improve the yield of WES. Moreover, novel mutations identified in TUBB4A, POLR3A, and POLR1C expand the mutation spectrum of these genes.


Asunto(s)
Predisposición Genética a la Enfermedad , Variación Genética , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/genética , Canales de Calcio/genética , Niño , Preescolar , ARN Polimerasas Dirigidas por ADN/genética , Ácido Graso Desaturasas/genética , Femenino , Pruebas Genéticas , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/diagnóstico , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Proteínas de la Membrana/genética , Mutación , Vaina de Mielina/metabolismo , Proteínas del Tejido Nervioso/genética , ARN Polimerasa III/genética , Empalme del ARN , Factores de Transcripción SOXE/genética , Tubulina (Proteína)/genética , Secuenciación del Exoma
9.
Hum Mol Genet ; 26(10): 1927-1941, 2017 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-28334874

RESUMEN

Genomic disorders are the clinical conditions manifested by submicroscopic genomic rearrangements including copy number variants (CNVs). The CNVs can be identified by array-based comparative genomic hybridization (aCGH), the most commonly used technology for molecular diagnostics of genomic disorders. However, clinical aCGH only informs CNVs in the probe-interrogated regions. Neither orientational information nor the resulting genomic rearrangement structure is provided, which is a key to uncovering mutational and pathogenic mechanisms underlying genomic disorders. Long-range polymerase chain reaction (PCR) is a traditional approach to obtain CNV breakpoint junction, but this method is inefficient when challenged by structural complexity such as often found at the PLP1 locus in association with Pelizaeus-Merzbacher disease (PMD). Here we introduced 'capture and single-molecule real-time sequencing' (cap-SMRT-seq) and newly developed 'asymmetry linker-mediated nested PCR walking' (ALN-walking) for CNV breakpoint sequencing in 49 subjects with PMD-associated CNVs. Remarkably, 29 (94%) of the 31 CNV breakpoint junctions unobtainable by conventional long-range PCR were resolved by cap-SMRT-seq and ALN-walking. Notably, unexpected CNV complexities, including inter-chromosomal rearrangements that cannot be resolved by aCGH, were revealed by efficient breakpoint sequencing. These sequence-based structures of PMD-associated CNVs further support the role of DNA replicative mechanisms in CNV mutagenesis, and facilitate genotype-phenotype correlation studies. Intriguingly, the lengths of gained segments by CNVs are strongly correlated with clinical severity in PMD, potentially reflecting the functional contribution of other dosage-sensitive genes besides PLP1. Our study provides new efficient experimental approaches (especially ALN-walking) for CNV breakpoint sequencing and highlights their importance in uncovering CNV mutagenesis and pathogenesis in genomic disorders.


Asunto(s)
Hibridación Genómica Comparativa/métodos , Variaciones en el Número de Copia de ADN/genética , Variaciones en el Número de Copia de ADN/fisiología , Enfermedad de Pelizaeus-Merzbacher/genética , Secuencia de Bases , Replicación del ADN , Femenino , Dosificación de Gen/genética , Duplicación de Gen/genética , Reordenamiento Génico/genética , Estudios de Asociación Genética/métodos , Genoma Humano , Genómica/métodos , Humanos , Masculino , Mutación , Enfermedad de Pelizaeus-Merzbacher/sangre , Análisis de Secuencia de ADN/métodos
10.
BMC Med Genet ; 20(1): 80, 2019 05 14.
Artículo en Inglés | MEDLINE | ID: mdl-31088393

RESUMEN

BACKGROUND: Intellectual disability/developmental delay is a complex condition with extraordinary heterogeneity. A large proportion of patients lacks a specific diagnosis. Next generation sequencing, enabling identification of genetic variations in multiple genes, has become an efficient strategy for genetic analysis in intellectual disability/developmental delay. METHODS: Clinical data of 112 Chinese families with unexplained intellectual disability/developmental delay was collected. Targeted next generation sequencing of 454 genes related to intellectual disability/developmental delay was performed for all 112 index patients. Patients with promising variants and their other family members underwent Sanger sequencing to validate the authenticity and segregation of the variants. RESULTS: Fourteen promising variants in genes EFNB1, MECP2, ATRX, NAA10, ANKRD11, DHCR7, LAMA1, NFIX, UBE3A, ARID1B and PTPRD were identified in 11 of 112 patients (11/112, 9.82%). Of 14 variants, eight arose de novo, and 13 are novel. Nine patients (9/112, 8.03%) got definite molecular diagnoses. It is the first time to report variants in EFNB1, NAA10, DHCR7, LAMA1 and NFIX in Chinese intellectual disability/developmental delay patients and first report about variants in NAA10 and LAMA1 in affected individuals of Asian ancestry. CONCLUSIONS: Targeted next generation sequencing of 454 genes is an effective test strategy for patients with unexplained intellectual disability/developmental delay. Genetic heterogenicity is significant in this Chinese cohort and de novo variants play an important role in the diagnosis. Findings of this study further delineate the corresponding phenotypes, expand the mutation spectrum and support the involvement of PTPRD in the disease.


Asunto(s)
Discapacidades del Desarrollo/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Discapacidad Intelectual/genética , Mutación , Adolescente , Niño , Preescolar , China , Cromosomas Humanos X , Femenino , Genes Dominantes , Genes Recesivos , Heterogeneidad Genética , Humanos , Lactante , Masculino , Linaje , Fenotipo
12.
Insects ; 15(8)2024 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-39194794

RESUMEN

Citrus huanglongbing (HLB) is a devastating disease for citrus production, largely caused by the Asian citrus psyllid (ACP). Poncirus trifoliata exhibits high resistance to ACP; however, this resistance is weakened when C. sinensis is co-cultivated. This study aimed to identify the differentially expressed genes (DEGs) during ACP feeding and to uncover potential ACP resistance genes in P. trifoliata. In comparison to independent cultivation, 1247 and 205 DEGs were identified in P. trifoliata when co-cultivated with C. sinensis after 7 and 14 days, respectively. Analysis of enriched Gene Ontology categories revealed that DEGs were significantly associated with the cell wall, glucometabolic activities, and secondary metabolites. Additionally, these genes were found to be involved in phytohormone signaling, cell wall metabolism, redox state homeostasis, and secondary metabolites, as well as a number of transcription factor genes (TFs). Furthermore, we examined the impact of the ACP feeding factor on the gene expression patterns in P. trifoliata. Results showed an increase in the JA signaling pathway and various TFs. The RNA-seq results were verified using reverse transcription quantitative PCR. Our findings shed light on the molecular basis of ACP resistance in P. trifoliata and identified potential genes associated with this resistance.

13.
Artículo en Inglés | MEDLINE | ID: mdl-39217461

RESUMEN

Esophageal cancer (EC) is one of the most fatal cancers all over the world. Sensitive detection modalities for early-stage EC and efficient treatment methods are urgently needed for the improvement of the prognosis of EC. Exosomes are small vesicles for intercellular communication, mediating many biological responses including cancer progression, which are not only promising biomarkers for diagnosis and prognosis but also therapeutic tools for EC. This review provides an overview of the relationships between exosomes and EC progression, as well as the application of exosomes in the diagnosis, prognosis, and treatment of EC. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.


Asunto(s)
Progresión de la Enfermedad , Neoplasias Esofágicas , Exosomas , Humanos , Exosomas/metabolismo , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/terapia , Neoplasias Esofágicas/metabolismo , Pronóstico , Animales , Biomarcadores de Tumor/metabolismo , Portadores de Fármacos/química
14.
Nat Commun ; 15(1): 4576, 2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38811553

RESUMEN

The flexible distribution network presents a promising architecture to accommodate highly integrated distributed generators and increasing loads in an efficient and cost-effective way. The distribution network is characterised by flexible interconnections and expansions based on soft open points, which enables it to dispatch power flow over the entire system with enhanced controllability and compatibility. Herein, we propose a multi-resource dynamic coordinated planning method of flexible distribution network that allows allocation strategies to be determined over a long-term planning period. Additionally, we establish a probabilistic framework to address source-load uncertainties, which mitigates the security risks of voltage violations and line overloads. A practical distribution network is adopted for flexible upgrading based on soft open points, and its cost benefits are evaluated and compared with that of traditional planning approaches. By adjusting the acceptable violation probability in chance constraints, a trade-off between investment efficiency and operational security can be realised.

15.
Adv Sci (Weinh) ; 11(4): e2305016, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38037482

RESUMEN

With outstanding advantages of chemical synthesis, structural diversity, and mechanical flexibility, molecular ferroelectrics have attracted increasing attention, demonstrating themselves as promising candidates for next-generation wearable electronics and flexible devices in the film form. However, it remains a challenge to grow high-quality thin films of molecular ferroelectrics. To address the above issue, a volume-confined method is utilized to achieve ultrasmooth single-crystal molecular ferroelectric thin films at the sub-centimeter scale, with the thickness controlled in the range of 100-1000 nm. More importantly, the preparation method is applicable to most molecular ferroelectrics and has no dependency on substrates, showing excellent reproducibility and universality. To demonstrate the application potential, two-dimensional (2D) transitional metal dichalcogenide semiconductor/molecular ferroelectric heterostructures are prepared and investigated by optical spectroscopic method, proving the possibility of integrating molecular ferroelectrics with 2D layered materials. These results may unlock the potential for preparing and developing high-performance devices based on molecular ferroelectric thin films.

16.
Adv Mater ; : e2413547, 2024 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-39491796

RESUMEN

Organic-inorganic hybrid perovskite ferroelectric has gained significant attention for its structural flexibility and diversity. They can directly utilize metal nodes and organic groups as active sites in catalysis. Additionally, their ferroelectric polarization occurs around these active sites, significantly enhancing catalytic activity and demonstrating immense potential for applications. However, their catalytic applications remain underexplored. This work marks the first utilization of the molecular perovskite ferroelectric [3,3-difluorocyclobutylammonium]2CuCl4 (Cu-DFCBA) as a catalyst for alkane oxidation. Under ultrasonic stimulation, it achieved a remarkable turnover number as high as 2402. Compared to inorganic ferroelectrics like lithium niobate (LiNbO3), the molecular ferroelectric exhibited a 1200-fold increase in catalytic activity. This highlights Cu-DFCBA's robust ferroelectric properties and underscores the vast potential of molecular ferroelectrics in catalysis, guiding future system designs.

17.
Adv Mater ; 36(31): e2401392, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38821489

RESUMEN

Anatomizing mixed-phases, referring to analyzing the mixing profiles and quantifying the phases' proportions in a material, which is of great significance in the genuine applications. Here, by using second-harmonic generation (SHG) polarimetry and piezoresponse force microscopy (PFM) techniques, this work elucidates the contributions and distributions of two different symmetric phases mixed in an archetype monoaxial molecular ferroelectric, diisopropylammonium chloride (DIPACl). The two competing phases are preferred in thermodynamics or kinetic process respectively, and this work evidences the switching behavior between the two competing phases facilitated by an external electrical field as opposed to a heating process. This research contributes novel insights into phase engineering in the field of molecular ferroelectrics and is poised to serve as a potent analytical tool for subsequent applications.

18.
Nat Commun ; 15(1): 4470, 2024 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-38796520

RESUMEN

Molecular ferroelectrics are attracting great interest due to their light weight, mechanical flexibility, low cost, ease of processing and environmental friendliness. These advantages make molecular ferroelectrics viable alternatives or supplements to inorganic ceramics and polymer ferroelectrics. It is expected that molecular ferroelectrics with good performance can be fabricated, which in turns calls for effective chemical design strategies in crystal engineering. To achieve so, we propose a hydrogen bond modification method by introducing the hydroxyl group, and successfully boost the phase transition temperature (Tc) by at least 336 K. As a result, the molecular ferroelectric 1-hydroxy-3-adamantanammonium tetrafluoroborate [(HaaOH)BF4] can maintain ferroelectricity until 528 K, a Tc value much larger than that of BTO (390 K). Meanwhile, micro-domain patterns, in stable state for 2 years, can be directly written on the film of (HaaOH)BF4. In this respect, hydrogen bond modification is a feasible and effective strategy for designing molecular ferroelectrics with high Tc and stable ferroelectric domains. Such an organic molecule with varied modification sites and the precise crystal engineering can provide an efficient route to enrich high-Tc ferroelectrics with various physical properties.

19.
J Mech Behav Biomed Mater ; 146: 106068, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37639934

RESUMEN

Many biological materials, such as bone and nacre, exhibit remarkable combinations of stiffness, strength, toughness, and impact resistance over millions of years of evolution. They provide prototypes for designing high-performance artificial composites. However, the dynamic properties of biological materials under impact loading are still not clear. In this study, we establish a dynamic shear-lag model to explore the dynamic response and the energy dissipation capacity of bioinspired staggered composites with a viscoelastic matrix under impact loading. The time domain solution of the dynamic shear-lag model is derived. Then, the model is verified by comparing it with the results from the finite element method. The results demonstrate that matrix viscosity plays a significant role in dissipating the impact energy and enhances the wave transformation between adjacent tablets. Furthermore, there exists an optimal viscosity coefficient to achieve an excellent balance between the rate and efficiency of energy dissipation. The model and the results can not only reveal the energy dissipation property of biological materials but also provide guidelines for the design and optimization of high-performance composites.


Asunto(s)
Nácar , Viscosidad
20.
Minerva Pediatr (Torino) ; 75(1): 32-38, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27057822

RESUMEN

BACKGROUND: Clinical and genetic features were analyzed in five pedigrees with Pelizaeus-Merzbacher-like disease (PMLD) to provide bases for genetic counseling and prenatal diagnosis. CONCLUSIONS: Six patients from five pedigrees were diagnosed with PMLD based on their clinical data. Six GJC2 novel mutations were found in this study, expanding the spectrum of GJC2 mutations. This is the second group of GJC2 mutations reported from six Chinese patients with PMLD. METHODS: Clinical data including medical history, physical signs, and auxiliary examinations were collected from six patients and their family numbers in five pedigrees with PMLD. Polymerase chain reaction and sequence analysis were used to amplify GJC2 and PLP1 alterations, while multiplex ligation-dependent probe amplification (MLPA) was performed to detect PLP1 dosage changes. The gene mutations were diagnosed for further analysis of the genetic features. RESULTS: A total of seven GJC2 mutations were identified in these patients, including two novel missense mutations (c.217C>T, p.Pro73Ser; c.1199C>A, p.Ala400Glu), one nonsense mutation (c.735C>A, p.Cys245X), three novel frameshift mutations (c.579delC, p.Gly193fsX17 and c.1296_1297insG, p.Gly433fsX59; c.689delG, p.Gly230AlafsX241), and one known missense mutation (c.814T>G, p.Tyr272Asp). Compound heterozygotes were found for P1-3, while homozygotes were found for P4-6 that were inherited from their parents with normal phenotypes except for P5 and P6, respectively. The c.814T>G (p.Tyr272Asp) mutation in P5 was de novo. A c.1199C>A (p.Ala400Glu) homozygous mutation in GJC2 was identified in P6. A heterozygous variation was found in his father and the wild type was seen in his mother.


Asunto(s)
Conexinas , Enfermedades Desmielinizantes , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias , Enfermedad de Pelizaeus-Merzbacher , Humanos , Pueblos del Este de Asia , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/genética , Mutación , Mutación Missense , Enfermedad de Pelizaeus-Merzbacher/genética , Conexinas/genética
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