Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 209
Filtrar
1.
J Hum Genet ; 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38866925

RESUMO

BACKGROUND: Intronic GAA repeat expansion ([GAA] ≥250) in FGF14 is associated with the late-onset neurodegenerative disorder, spinocerebellar ataxia 27B (SCA27B, GAA-FGF14 ataxia). We aim to determine the prevalence of the GAA repeat expansion in FGF14 in Chinese populations presenting late-onset cerebellar ataxia (LOCA) and evaluate the characteristics of tandem repeat inheritance, radiological features and sympathetic nerve involvement. METHODS: GAA-FGF14 repeat expansion was screened in an undiagnosed LOCA cohort (n = 664) and variations in repeat-length were analyzed in families of confirmed GAA-FGF14 ataxia patients. Brain magnetic resonance imaging (MRI) was used to evaluate the radiological feature in GAA-FGF14 ataxia patients. Clinical examinations and sympathetic skin response (SSR) recordings in GAA-FGF14 patients (n = 16) were used to quantify sympathetic nerve involvement. RESULTS: Two unrelated probands (2/664) were identified. Genetic screening for GAA-FGF14 repeat expansion was performed in 39 family members, 16 of whom were genetically diagnosed with GAA-FGF14 ataxia. Familial screening revealed expansion of GAA repeats in maternal transmissions, but contraction upon paternal transmission. Brain MRI showed slight to moderate cerebellar atrophy. SSR amplitude was lower in GAA-FGF14 patients in pre-symptomatic stage compared to healthy controls, and further decreased in the symptomatic stage. CONCLUSIONS: GAA-FGF14 ataxia was rare among Chinese LOCA cases. Parental gender appears to affect variability in GAA repeat number between generations. Reduced SSR amplitude is a prominent feature in GAA-FGF14 patients, even in the pre-symptomatic stage.

2.
J Am Chem Soc ; 146(20): 13886-13893, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38739909

RESUMO

Guest-induced (crystal-to-crystal) transformation, i.e., periodic flexibility, is a typical feature of molecule-based crystalline porous materials, but its role for adsorptive separation is controversial. On the other hand, aperiodic flexibility is rarely studied. This work reports a pair of isomeric Cu(I) triazolate frameworks, namely, α-[Cu(fetz)] (MAF-2Fa) and ß-[Cu(fetz)] (MAF-2Fb), which show typical periodic and aperiodic flexibility for CO chemical adsorption, respectively. Quantitative mixture breakthrough experiments show that, while MAF-2Fa exhibits high adsorption capacity at high pressures but negligible adsorption below the threshold pressure and with leakage concentrations of 3-8%, MAF-2Fb exhibits relatively low adsorption capacity at high pressures but no leakage (residual CO concentration <1 ppb). Tandem connection of MAF-2Fa and MAF-2Fb can combine their advantages of high CO adsorption capacities at high and low pressures, respectively. MAF-2Fa and MAF-2Fb can both keep the separation performances unchanged at high relative humidities, but only MAF-2Fb shows a unique coadsorption behavior at a relative humidity of 82%, which can be used to improve purification performances.

3.
Angew Chem Int Ed Engl ; : e202404271, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38700507

RESUMO

Integrating controllable spin states into single-molecule magnets (SMMs) enables precise manipulation of magnetic interactions at a molecular level, but remains a synthetic challenge. Herein, we developed a 3d-4f metallacrown (MC) magnet [DyNi5(quinha)5(Clsal)2(py)8](ClO4) ⋅ 4H2O (H2quinha=quinaldichydroxamic acid, HClsal=5-chlorosalicylaldehyde) wherein a square planar NiII is stabilized by chemical stacking. Thioacetal modification was employed via post-synthetic ligand substitutions and yielded [DyNi5(quinha)5(Clsaldt)2(py)8](ClO4) ⋅ 3H2O (HClsaldt=4-chloro-2-(1,3-dithiolan-2-yl)phenol). Thanks to the additional ligations of thioacetal onto the NiII site, coordination-induced spin state switching (CISSS) took place with spin state altering from low-spin S=0 to high-spin S=1. The synergy of CISSS effect and magnetic interactions results in distinct energy splitting and magnetic dynamics. Magnetic studies indicate prominent enhancement of reversal barrier from 57 cm-1 to 423 cm-1, along with hysteresis opening and an over 200-fold increment in coercive field at 2 K. Ab initio calculations provide deeper insights into the exchange models and rationalize the relaxation/tunnelling pathways. These results demonstrate here provide a fire-new perspective in modulating the magnetization relaxation via the incorporation of controllable spin states and magnetic interactions facilitated by the CISSS approach.

4.
Angew Chem Int Ed Engl ; : e202407675, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38770616

RESUMO

Manipulating the crystal orientation plays a crucial role in the conversion efficiency during second harmonic generation (SHG). Here, we provide a new strategy in controlling the surface-dependent anisotropic SHG with the precise design of (101) and (2 1 ‾ ${\bar 1}$ 0) MAGeI3 facets. Based on the SHG measurement, the (101) MAGeI3 single crystal exhibits larger SHG (1.3×(2 1 ‾ ${\bar 1}$ 0) MAGeI3). Kelvin probe force microscopy imaging shows a smaller work function for the (101) MAGeI3 compared with the (2 1 ‾ ${\bar 1}$ 0), which indirectly demonstrates the stronger intrinsic polarization on the (101) surface. X-ray photoelectron spectroscopy confirms the band bending within the (101) facet. Temperature-dependent steady-state and time-resolved photoluminescence spectroscopy show shorter lifetime and wider emission band in the (101) MAGeI3 single crystal, revealing the higher defect states. Additionally, powder X-ray diffraction patterns show the (101) MAGeI3 possesses larger in-plane polar units [GeI3]- density, which could directly enhance the spontaneous polarization in the (101) facet. Density functional theory (DFT) calculation further demonstrates the higher intrinsic polarization in the (101) facet compared with the (2 1 ‾ ${\bar 1}$ 0) facet, and the larger built-in electric field in the (101) facet facilitates surface vacancy defect accumulation. Our work provides a new angle in tuning and optimizing hybrid perovskite-based nonlinear optical materials.

5.
J Genet Genomics ; 51(5): 554-565, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38575109

RESUMO

The Fagaceae, a plant family with a wide distribution and diverse adaptability, has garnered significant interest as a subject of study in plant speciation and adaptation. Meanwhile, certain Fagaceae species are regarded as highly valuable wood resources due to the exceptional quality of their wood. In this study, we present two high-quality, chromosome-scale genome sequences for Quercus sichourensis (848.75 Mb) and Quercus rex (883.46 Mb). Comparative genomics analysis reveals that the difference in the number of plant disease resistance genes and the nonsynonymous and synonymous substitution ratio (Ka/Ks) of protein-coding genes among Fagaceae species are related to different environmental adaptations. Interestingly, most genes related to starch synthesis in the investigated Quercoideae species are located on a single chromosome, as compared to the outgroup species, Fagus sylvatica. Furthermore, resequencing and population analysis of Q. sichourensis and Q. rex reveal that Q. sichourensis has lower genetic diversity and higher deleterious mutations compared to Q. rex. The high-quality, chromosome-level genomes and the population genomic analysis of the critically endangered Q. sichourensis and Q. rex will provide an invaluable resource as well as insights for future study in these two species, even the genus Quercus, to facilitate their conservation.


Assuntos
Adaptação Fisiológica , Cromossomos de Plantas , Genoma de Planta , Quercus , Quercus/genética , Genoma de Planta/genética , Cromossomos de Plantas/genética , Adaptação Fisiológica/genética , Evolução Molecular , Filogenia , Variação Genética/genética , Genômica , Resistência à Doença/genética
6.
Inorg Chem ; 63(17): 7966-7972, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38620044

RESUMO

Hybrid ferroelastic crystals have emerged as a hot research topic in recent years owing to their prospective applications in piezoelectric sensors, mechanical switches, and optoelectronic devices. Nevertheless, most of the documented materials exhibit one-step or two-step ferroelastic phase transition(s), and those with multistep ferroelastic transitions are extremely scarce. We present a new hexagonal molecular perovskite based on a fluoro-substituted flexible cyclic ammonium cation, (1-fluoromethyl-1-methylpyrrolidine)[CdCl3] (1), undergoing unusual three-step ferroelastic phase transitions from hexagonal paraelastic phase to orthorhombic, monoclinic, and triclinic ferroelastic phases at 388, 376, and 311 K, respectively, with Aizu notation of 6/mmmFmmm, mmmF2/m, and 2/mF-1, featuring spontaneous strain of 0.002, 0.023, and 0.110, respectively. Furthermore, variable-temperature single-crystal diffraction reveals that the phase-transition mechanism in 1 principally originates from intriguing dynamic change of organic cations and synchronous displacement of inorganic chains. This scarce instance of multistep hybrid ferroelastic provides important clues for finding advanced ferroelastic materials.

7.
Chem Sci ; 15(10): 3661-3669, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38455005

RESUMO

Ferroelastic materials have gained widespread attention as promising candidates for mechanical switches, shape memory, and information processing. Their phase-transition mechanisms usually originate from conventional order-disorder and/or displacive types, while those involving dynamic coordination bonds are still scarce. Herein, based on a strategic molecular design of organic cations, we report three new polar hybrid crystals with a generic formula of AA'RbBiCl6 (A = A' = Me3SO+ for 1; A = Me3SO+ and A' = Me4N+ for 2; A = A' = Me3NNH2+ for 3). Their A-site cations link to the [RbBiCl6]n2n- inorganic framework with lon topology through Rb-O/N coordination bonds, while their significantly different interactions between A'-site cations and inorganic frameworks provide distinct phase-transition behaviour. In detail, the strongly coordinative A'-site Me3SO+ cations prevent 1 from a structural phase transition, while coordinatively free A'-site Me4N+ cations trigger a conventional order-disorder ferroelastic transition at 247 K in 2, accompanied by a latent heat of 0.63 J g-1 and a usual "high → low" second-harmonic-generation (SHG) switch. Interestingly, the A'-site Me3NNH2+ cations in 3 reveal unusual dynamic coordination bonds, driving a high-temperature ferroelastic transition at 369 K with a large latent heat of 18.34 J g-1 and an unusual "low → high" SHG-switching behaviour. This work provides an effective molecular assembly strategy to establish dynamic coordination bonds in a new type of host-guest model and opens an avenue for designing advanced ferroelastic multifunctional materials.

8.
Asian J Psychiatr ; 91: 103803, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37992593

RESUMO

BACKGROUND: Symptom-based diagnostic criteria of depression leads to notorious heterogeneity and subjectivity. METHODS: The study was conducted in two stages at two sites: development of a neuroimaging-based subtyping and precise repetitive transcranial magnetic stimulation (rTMS) strategy for depression at Center 1 and its clinical application at Center 2. Center 1 identified depression subtypes and subtype-specific rTMS targets based on amplitude of low frequency fluctuation (ALFF) in a cohort of 238 major depressive disorder patients and 66 healthy controls (HC). Subtypes were identified using a Gaussian Mixture Model, and subtype-specific rTMS targets were selected based on dominant brain regions prominently differentiating depression subtypes from HC. Subsequently, one classifier was employed and 72 hospitalized, depressed youths at Center 2 received two-week precise rTMS. MRI and clinical assessments were obtained at baseline, midpoint, and treatment completion for evaluation. RESULTS: Two neuroimaging subtypes of depression, archetypal and atypical depression, were identified based on distinct frontal-posterior functional imbalance patterns as measured by ALFF. The dorsomedial prefrontal cortex was identified as the rTMS target for archetypal depression, and the occipital cortex for atypical depression. Following precise rTMS, ALFF alterations were normalized in both archetypal and atypical depressed youths, corresponding with symptom response of 90.00% in archetypal depression and 70.73% in atypical depression. CONCLUSIONS: A precision medicine framework for depression was developed based on objective neurobiomarkers and implemented with promising results, actualizing a subtyping-treatment-evaluation closed loop in depression. Future randomized controlled trials are warranted.


Assuntos
Transtorno Depressivo Maior , Humanos , Adolescente , Transtorno Depressivo Maior/diagnóstico por imagem , Transtorno Depressivo Maior/terapia , Depressão , Medicina de Precisão , Encéfalo/diagnóstico por imagem , Estimulação Magnética Transcraniana/métodos , Neuroimagem , Córtex Pré-Frontal , Resultado do Tratamento
9.
Nat Mater ; 23(1): 116-123, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37957269

RESUMO

Carbon monoxide (CO) separation relies on chemical adsorption but suffers from the difficulty of desorption and instability of open metal sites against O2, H2O and so on. Here we demonstrate quasi-open metal sites with hidden or shielded coordination sites as a promising solution. Possessing the trigonal coordination geometry (sp2), Cu(I) ions in porous frameworks show weak physical adsorption for non-target guests. Rational regulation of framework flexibility enables geometry transformation to tetrahedral geometry (sp3), generating a fourth coordination site for the chemical adsorption of CO. Quantitative breakthrough experiments at ambient conditions show CO uptakes up to 4.1 mmol g-1 and CO selectivity up to 347 against CO2, CH4, O2, N2 and H2. The adsorbents can be completely regenerated at 333-373 K to recover CO with a purity of >99.99%, and the separation performances are stable in high-concentration O2 and H2O. Although CO leakage concentration generally follows the structural transition pressure, large amounts (>3 mmol g-1) of ultrahigh-purity (99.9999999%, 9N; CO concentration < 1 part per billion) gases can be produced in a single adsorption process, demonstrating the usefulness of this approach for separation applications.

10.
Langmuir ; 39(48): 17308-17317, 2023 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-37974298

RESUMO

The adhesion of probiotics plays an important role in the gastrointestinal tract. Understanding the effect of the coverage of colonized probiotics on enteric pathogens is critical for the design of effective probiotic therapies. In the present work, we have investigated the adaptive behaviors of the intestinal pathogenic bacteria Enterobacter sakazakii (ES) near the surfaces coated with a probiotic─Lactobacillus rhamnosus GG (LGG) as a function of surface coverage ratio (CRLGG) by using a home-setup digital holographic microscopy. It shows that ES cells can adaptively sense LGG within a distance of 4.2 µm, even at CRLGG values as low as 0.05%. The growth inhibition of ES cells slightly varies with CRLGG, but the near-surface acceleration and accumulation of ES cells have much dependence on CRLGG. As CRLGG increases from 0.05 to 24.6%, the percentage of actively swimming ES, the motion bias, the acceleration, and the interplay duration do not linearly vary with CRLGG. Instead, each of them shows an extreme at CRLGG of 13.4%, corresponding to the chemotaxis behaviors of ES cells induced by diffusing stimuli (organic acids, bacteriocins, etc.) released from LGG, which showed an extreme concentration gradient at CRLGG = 13.4% by simulations. Our study clearly demonstrates that surface coverage of sessile probiotics profoundly influences their interplay with pathogen bacteria, which should be taken into account in designing probiotic therapies.


Assuntos
Lacticaseibacillus rhamnosus , Probióticos , Microscopia , Trato Gastrointestinal
11.
Langmuir ; 39(49): 17632-17643, 2023 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-38033279

RESUMO

To understand the antimicrobial effect of surfaces fabricated with dead probiotics, we prepared surfaces decorated with dead probiotics Lactobacillus rhamnosus GG (LGG) with varied inactivation methods and explored their inhibitory interactions with Pseudomonas aeruginosa (PAO1). By combining several techniques, i.e., digital holographic microscopy (DHM), atomic force microscopy (AFM), RNA sequencing, and metabolomic analysis, we studied the three-dimensional (3D) swimming behaviors, surface adhesion, biofilm formation, and adaptive responses of PAO1 near such surfaces. The results show that planktonic PAO1 decreases their flick and reverse motions by downregulating the chemotaxis pathway and accelerates with less accumulation near dead LGG surfaces by upregulating the flagellar assembly pathway and decreasing cyclic adenosine monophosphate. Distinct from live siblings, the surfaces decorated with dead LGG show a significant reduction in adhesion strength with PAO1 and inhibit biofilm formation with more downregulated genes in the Pseudomonas quinolone signal and biofilm formation pathway. We demonstrate that the antibacterial ability of such surfaces stems from the gradually released lysate from the dead LGG that is unfavorable to PAO1 in close proximity. The releasing rate and order depend on the cell membrane integrity, which closely relates to the inactivation methods.


Assuntos
Lacticaseibacillus rhamnosus , Probióticos , Biofilmes , Pseudomonas aeruginosa/fisiologia , Microscopia de Força Atômica , Probióticos/farmacologia
12.
Biol Direct ; 18(1): 55, 2023 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-37670359

RESUMO

BACKGROUND: The active pursuit of network medicine for drug repurposing, particularly for combating Covid-19, has stimulated interest in the concept of structural controllability in cellular networks. We sought to extend this theory, focusing on the defense rather than control of the cell against viral infections. Accordingly, we extended structural controllability to total structural controllability and introduced the concept of control hubs. Perturbing any control hub may render the cell uncontrollable by exogenous stimuli like viral infections, so control hubs are ideal drug targets. RESULTS: We developed an efficient algorithm to identify all control hubs, applying it to a largest homogeneous network of human protein interactions, including interactions between human and SARS-CoV-2 proteins. Our method recognized 65 druggable control hubs with enriched antiviral functions. Utilizing these hubs, we categorized potential drugs into four groups: antiviral and anti-inflammatory agents, drugs acting on the central nervous system, dietary supplements, and compounds enhancing immunity. An exemplification of our approach's effectiveness, Fostamatinib, a drug initially developed for chronic immune thrombocytopenia, is now in clinical trials for treating Covid-19. Preclinical trial data demonstrated that Fostamatinib could reduce mortality rates, ICU stay length, and disease severity in Covid-19 patients. CONCLUSIONS: Our findings confirm the efficacy of our novel strategy that leverages control hubs as drug targets. This approach provides insights into the molecular mechanisms of potential therapeutics for Covid-19, making it a valuable tool for interpretable drug discovery. Our new approach is general and applicable to repurposing drugs for other diseases.


Assuntos
COVID-19 , Humanos , Tratamento Farmacológico da COVID-19 , SARS-CoV-2 , Antivirais
13.
Chem Commun (Camb) ; 59(75): 11264-11267, 2023 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-37661855

RESUMO

Integrating NH4+ as a B'-site ion within a three-dimensional double hybrid perovskite resulted in a novel high-temperature ferroelastic, (Me3NOH)2(NH4)[Co(CN)6], which uniquely demonstrates a reversible triclinic-to-cubic phase transition at 369 K and offers a record-setting 24 orientation states, the highest ever reported among all ferroelastics.

14.
J Phys Chem Lett ; 14(36): 8009-8015, 2023 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-37651131

RESUMO

Free accessible confined space and loose interaction are crucial for most solid-state ionic motions. Here, by using a near-spherical anion and a disc-shaped ammonium as two distinct but rigid building blocks, we report a new ionic crystal, (HMIm)3[La(NO3)6] (HMIm = 1-methyl-1H-imidazol-3-ium), in which the different confined spaces of three (HMIm)+ ions are fine-tuned over a broad temperature range. This effect can be utilized to modulate the dipolar polarization across a wide temperature/frequency range. Additionally, small-scale substitution of (HMIm)+ by its isomer of almost identical shape/size affords molecular solid solutions, which can further tune the dipolar polarization by varying the doping ratio. It is revealed that the differences in dipole moment and hydrogen bond rather than that of shape/size lead to a distorted crystalline environment for these solid solutions. Overall, we provide an exceptional model for understanding and regulating the dipole motion of polar aromatic molecules/ions in a crystalline environment.

15.
Chem Asian J ; 18(19): e202300608, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37553296

RESUMO

Endowing room-temperature polymorphs with both long-term stability and easy interconvertibility is a big challenge due to the complexity of intermolecular interactions. Herein, we present a chiral hexagonal perovskite (R-3-hydroxy-1-methylpiperidinium)[CdCl3 ] having two room-temperature crystalline forms featuring obviously distinct second-harmonic-generation (SHG) signals with a high switching contrast of ~18 times. The two room-temperature forms could be long-term stable yet easily interconvertible through an irreversible thermal-induced phase transition and a pressure-driven backward transition, by switching hydrogen bonds via collective reorientation of ordered homochiral cations. Based on the essential role of homochiral organic cations in inducing switchable hydrogen bond linkages, this present instance provides good evidence that relatively irregular organic cations could induce more obvious inorganic chain deformations, thus endowing polymorphs with significantly different SHG signals at room temperature.

16.
Res Sq ; 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37503262

RESUMO

Background The active pursuit of network medicine for drug repurposing, particularly for combating Covid-19, has stimulated interest in the concept of structural control capability in cellular networks. We sought to extend this theory, focusing on the defense rather than control of the cell against viral infections. Accordingly, we extended structural controllability to total structural controllability and introduced the concept of control hubs. Perturbing any control hub may render the cell uncontrollable by exogenous stimuli like viral infections, so control hubs are ideal drug targets. Results We developed an efficient algorithm to identify all control hubs, applying it to the largest homogeneous network of human protein interactions, including interactions between human and SARS-CoV-2 proteins. Our method recognized 65 druggable control hubs with enriched antiviral functions. Utilizing these hubs, we categorized potential drugs into four groups: antiviral and anti-inflammatory agents, drugs acting on the central nervous system, dietary supplements, and compounds enhancing immunity. An exemplification of our approach's effectiveness, Fostamatinib, a drug initially developed for chronic immune thrombocytopenia, is now in clinical trials for treating Covid-19. Preclinical trial data demonstrated that Fostamatinib could reduce mortality rates, ICU stay length, and disease severity in Covid-19 patients. Conclusions Our findings confirm the efficacy of our novel strategy that leverages control hubs as drug targets. This approach provides insights into the molecular mechanisms of potential therapeutics for Covid-19, making it a valuable tool for interpretable drug discovery.

17.
iScience ; 26(8): 107296, 2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37520717

RESUMO

Finding cancer-driver genes has been a central theme of cancer research. We took a different perspective; instead of considering normal cells, we focused on cancerous cells and genes that maintained abnormal cell growth, which we named cancer-keeper genes (CKGs). Intervening CKGs may rectify aberrant cell growth, making them potential cancer therapeutic targets. We introduced control-hub genes and developed an efficient algorithm by extending network controllability theory. Control hub are essential for maintaining cancerous states and thus can be taken as CKGs. We applied our CKG-based approach to bladder cancer (BLCA). All genes on the cell-cycle and p53 pathways in BLCA were identified as CKGs, showing their importance in cancer. We discovered that sensitive CKGs - genes easily altered by structural perturbation - were particularly suitable therapeutic targets. Experiments on cell lines and a mouse model confirmed that six sensitive CKGs effectively suppressed cancer cell growth, demonstrating the immense therapeutic potential of CKGs.

18.
J Am Chem Soc ; 145(25): 13663-13673, 2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37329320

RESUMO

The development of photo-responsive ferroelectrics whose polarization may be remotely controlled by optical means is of fundamental importance for basic research and technological applications. Herein, we report the design and synthesis of a new metal-nitrosyl ferroelectric crystal (DMA)(PIP)[Fe(CN)5(NO)] (1) (DMA = dimethylammonium, PIP = piperidinium) with potential phototunable polarization via a dual-organic-cation molecular design strategy. Compared to the parent non-ferroelectric (MA)2[Fe(CN)5(NO)] (MA = methylammonium) material with a phase transition at 207 K, the introduction of larger dual organic cations both lowers the crystal symmetry affording robust ferroelectricity and increases the energy barrier of molecular motions, endowing 1 with a large polarization of up to 7.6 µC cm-2 and a high Curie temperature (Tc) of 316 K. Infrared spectroscopy shows that the reversible photoisomerization of the nitrosyl ligand is accomplished by light irradiation. Specifically, the ground state with the N-bound nitrosyl ligand conformation can be reversibly switched to both the metastable state I (MSI) with isonitrosyl conformation and the metastable state II (MSII) with side-on nitrosyl conformation. Quantum chemistry calculations suggest that the photoisomerization significantly changes the dipole moment of the [Fe(CN)5(NO)]2- anion, thus leading to three ferroelectric states with different values of macroscopic polarization. Such optical accessibility and controllability of different ferroelectric states via photoinduced nitrosyl linkage isomerization open up a new and attractive route to optically controllable macroscopic polarization.

19.
Chem Sci ; 14(22): 5965-5973, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37293638

RESUMO

Hybrid ferroelastics have attracted increasing attention for their potential application as mechanical switches. The sporadically documented anomalous ferroelastic phase transitions, i.e., ferroelasticity that appears at a high-temperature phase rather than a low-temperature phase, are of particular interest but are not well understood at the molecular level. By judiciously choosing a polar and flexible organic cation (Me2NH(CH2)2Br+) with cis-/anti- conformations as an A-site component, we obtained two new polar hybrid ferroelastics, A2[MBr6] (M = Te for 1 and Sn for 2). These materials undergo distinct thermal-induced ferroelastic phase transitions. The larger [TeBr6]2- anions anchor the adjacent organic cations well and essentially endow 1 with a conventional ferroelastic transition (P21 → Pm21n) arising from a common order-disorder transition of organic cations without conformational changes. Moreover, the smaller [SnBr6]2- anions can interact with the adjacent organic cations in energetically similar sets of intermolecular interactions, enabling 2 to undergo an anomalous ferroelastic phase transition (P212121 → P21) arising from an unusual cis-/anti-conformational reversal of organic cations. These two instances demonstrate the importance of the delicate balance of intermolecular interactions for inducing anomalous ferroelastic phase transitions. The findings here provide important insights for seeking new multifunctional ferroelastic materials.

20.
Sci Rep ; 13(1): 7957, 2023 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-37198299

RESUMO

Biosurfactants are attracting much interest due to their potential application as therapeutic agents in the medical and cosmetic field. Previous studies have demonstrated that biosurfactant such as sophorolipid (SL) exhibits immunomodulatory effects. In this article, we found the potential of sophorolipid for inhibiting histamine-induced itch and preliminarily explored its molecular basis. First, behavioral tests indicated that SL can remit the histamine-induced scratching behaviors of mice. Second, SL can suppress the the calcium influx induced by histamine, HTMT and VUF8430 in HaCaT cells. RT-PCR analysis showed that the histamine-induced upregulation of mRNA levels of phospholipase Cγ1, 1,4,5-trisphosphate receptor (IP3R), and protein kinase Cα can be inhibted by SL, suggesting that SL may impede the PLC/IP3R signaling pathway activated by histamine. In further tests, the capsaicin-induced calcium influx can also be inhibited by SL. The immunofluorescence and molecular docking analysis indicated that SL acts as an inhibitor of transient receptor potential vanilloid-1 (TRPV1) activation to decrease calcium influx against stimuli. In summary, these results revealed that SL may inhibit histamine-induced itch by decreasing PLC/IP3R signaling pathway activation and modulating TRPV1 activity. This paper indicates that SL can be a useful treatment for histamine-dependent itch.


Assuntos
Cálcio , Histamina , Camundongos , Animais , Histamina/metabolismo , Cálcio/metabolismo , Simulação de Acoplamento Molecular , Prurido/induzido quimicamente , Prurido/tratamento farmacológico , Prurido/metabolismo , Transdução de Sinais , Canais de Cátion TRPV/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...