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1.
Ageing Res Rev ; : 100965, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31678652

RESUMO

Dementia represents one of the most common neurodegenerative disorders in older adults. However, it is still unclear whether non-pharmacological therapies (NPTs) are effective or not and which treatment should be preferred. We applied a series of search strategies to identify eligible randomized controlled trials on 1st October, 2018, investigating the effects of NPTs of dementia in the older persons. Pairwise and network meta-analyses were sequentially performed. A total of 31 trials were included, which enrolled 1895 participants and 7 NPTs. Compared with control group, all the NPTs included were statistically beneficial to cognitive function, and our study indicated Comprehensive Therapy(CT) [the surface under the cumulative ranking curve(SUCRA=92.42%)] might be the best choice for dementia patients. Our study suggests CT might be the optimal NPT for improving the cognitive function of dementia patients. However, the above conclusions need to be further analyzed.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31621994

RESUMO

Galvanic replacement is a versatile approach to prepare hollow nanostructures with controllable morphology and elemental composition. The primary issue is to identify its fundamental mechanism. In this study, in situ liquid cell transmission electron microscopy was employed to monitor the dynamic reaction process and to explore the mechanism of galvanic replacement. The detailed reaction process was revealed based on in situ experiments in which small Au particles first appeared around Ag nanowires; they coalesced, grew, and adhered to Ag nanowires. After that, small pits grew from the edge of Ag nanowires to form tubular structures, and then extended along the Ag nanowires to obtain hollowed structures. All of our experimental observations from the viewpoint of electron microscopy, combined with DFT calculations, contribute towards an in-depth understanding of the galvanic replacement reaction process and the design of new materials with hollow structures.

3.
Int J Cancer ; 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31584185

RESUMO

We have developed an oncolytic Newcastle disease virus (NDV) that has potent in vitro and in vivo anti-tumor activities and attenuated pathogenicity in chickens. In this ex vivo study using the same recombinant NDV backbone with GFP transgene (NDV-GFP, designated as rNDV), we found that rNDV induces maturation of monocyte-derived immature dendritic cells (iDCs) by both direct and indirect mechanisms, which promote development of antigen-specific T cell responses. Addition of rNDV directly to iDCs culture induced DC maturation, as demonstrated by the increased expression of costimulatory and antigen-presenting molecules as well as the production of type I interferons (IFNs). rNDV infection of the HER-2 positive human breast cancer cell line (SKBR3) resulted in apoptotic cell death, release of proinflammatory cytokines, and danger-associated molecular pattern molecules (DAMPs) including high-mobility group protein B1 (HMGB1) and heat shock protein 70 (HSP70). Addition of rNDV-infected SKBR3 cells to iDC culture resulted in greatly enhanced upregulation of the maturation markers and release of type I IFNs by DCs than rNDV-infected DCs only. When co-cultured with autologous T cells, DCs pre-treated with rNDV-infected SKBR3 cells cross-primed T cells in an antigen-specific manner. Altogether, our data strongly support the potential of oncolytic NDV as efficient therapeutic agent for cancer treatment.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31627192

RESUMO

We performed first-principles calculations to investigate the phononic properties of these materials and theoretically confirmed that the Kohn anomaly originates from the lower transverse acoustic mode along the ГX direction, thereby revealing the frequency derivative discontinuity of the mode. In particular, the Kohn anomaly region is found to move from the interior to the boundary X point of the Brillouin zone with increasing number of valence electrons. We deduced that the Kohn anomaly originated from the electrons of the filled energy level near the van Hove singularity. These results suggest that the screening of the ionic electric field decreases, while the coupling of conduction electrons with the highly degenerate modes between the TA∥ and LA via Umklapp scattering process increases. The Fermi surface nesting also plays a role in enhancing the superconductivity. The electronic excitation effect induces a stabilization of the VB group transition metal nitrides.

5.
ACS Appl Mater Interfaces ; 11(39): 35924-35934, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31525945

RESUMO

Imide functionalization is one of the most effective approaches to develop electron-deficient building blocks for constructing n-type organic semiconductors. Driven by the attractive properties of imide-functionalized dithienylbenzodiimide (TBDI) and the promising device performance of TBDI-based polymers, a novel acceptor with increased electron affinity, fluorinated dithienylbenzodiimide (TFBDI), was designed with the hydrogen replaced by fluorine on the benzene core, and the synthetic challenges associated with this highly electron-deficient fluorinated imide building block are successfully overcome. TFBDI showed suppressed frontier molecular orbital energy levels as compared with TBDI. Copolymerizing this new electron-withdrawing TBDI with various donor co-units afforded a series of n-type polymer semiconductors TFBDI-T, TFBDI-Se, and TFBDI-BSe. All these TFBDI-based polymers exhibited a lower-lying lowest unoccupied molecular orbital (LUMO) energy level than the polymer analogue without fluorine. When applied in organic thin-film transistors, three polymers showed unipolar electron transport with large on-current/off-current ratios (Ion/Ioff) of 105-107. Among them, the selenophene-based polymer TFBDI-Se with the deepest-positioned LUMO and optimal chain stacking exhibited the highest electron mobility of 0.30 cm2 V-1 s-1. This result demonstrates that the new TFBDI is a highly attractive electron-deficient unit for enabling n-type polymer semiconductors, and the fluorination of imide-functionalized arenes offers an effective approach to develop more electron-deficient building blocks in organic electronics.

6.
Dalton Trans ; 48(40): 14989-14995, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31498343

RESUMO

Designing photocatalysts with heterostructures is an effective way to promote visible-light-driven photocatalytic degradation. Herein, a series of 2D/2D heterojunction photocatalysts, denoted as CuPor-Ph-COF/g-C3N4 composites, were prepared through in situ synthesis on the surface of g-C3N4 by a facile liquid-assisted grinding method. The photocatalytic performance of the as-prepared CuPor-Ph-COF/g-C3N4 composites was evaluated by the degradation of a model pollutant rhodamine B. The CuPor-Ph-COF/g-C3N4 composites displayed superior photocatalytic performance to pure g-C3N4 or pure CuPor-Ph-COF because of the faster separation of photogenerated charges. This represents the first composite fabricated between a 2D porphyrin-based covalent organic framework (COF) and g-C3N4, demonstrating not only the possibility but also more importantly the affordability of the application of costly porphyrin-based COFs in catalysis.

7.
Transplantation ; 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31343576

RESUMO

BACKGROUND: Given the potential utility of frailty, a clinical phenotype of decreased physiologic reserve and resistance to stressors, to predict post-kidney transplant (KT) outcomes, we sought to understand the perceptions and practices regarding frailty measurement in US KT programs. METHODS: Surveys were emailed to American Society of Transplantation Kidney/Pancreas Community of Practice members and 202 US transplant programs (11/2017-4/2018). Program characteristics were gleaned from SRTR. RESULTS: The 133 responding programs (response rate=66%) represented 77% of adult KTs and 79% of adult KT candidates in the US. Respondents considered frailty to be a useful concept in evaluating candidacy (99%) and endorsed a need to develop a frailty measurement specific to KT (92%). Frailty measurement was more common during candidacy evaluation (69%) than during KT admission (28%). Of the 202 programs, 38% performed frailty assessments in all candidates while 23% performed assessments only for older candidates. There was heterogeneity in the frailty assessment method; 18 different tools were utilized to measure frailty. The most common tool was a timed walk test (19%); 67% reported performing >1 tool. Among programs that measure frailty, 53% reported being less likely to list frail patients for KT. CONCLUSIONS: Among US KT programs, frailty is recognized as a clinically relevant construct and is commonly measured at evaluation. However, there is considerably heterogeneity in the tools used to measure frailty. Efforts to identify optimal measurement of frailty using either an existing or novel tool and subsequent standardization of its measurement and application across KT programs should be considered.

8.
Biomaterials ; 217: 119326, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31288173

RESUMO

Spinal cord injury (SCI) leads to immediate disruption of neuronal membranes and loss of neurons, followed by extensive secondary injury process. Treatment of SCI still remains a tremendous challenge clinically. Minocycline could target comprehensive secondary injury via anti-inflammatory, anti-oxidant and anti-apoptotic mechanisms. Polyethylene glycol (PEG), a known sealing agent, is able to seal the damaged cell membranes and reduce calcium influx, thereby exerting neuroprotective capacity. Here, an E-selectin-targeting sialic acid - polyethylene glycol - poly (lactic-co-glycolic acid) (SAPP) copolymer was designed for delivering hydrophobic minocycline to achieve combinational therapy of SCI. The obtained SAPP copolymer could self-assemble into micelles with critical micelle concentration being of 13.40 µg/mL, and effectively encapsulate hydrophobic minocycline. The prepared drug-loaded micelles (SAPPM) displayed sustained drug release over 72 h, which could stop microglia activation and exhibited excellent neuroprotective capacity in vitro. The SAPP micelles were efficiently accumulated in the lesion site of SCI rats via the specific binding between sialic acid and E-selectin. Due to the targeting distribution and combinational effect between PEG and minocycline, SAPPM could obviously reduce the area of lesion cavity, and realize more survival of axons and myelin sheaths from the injury, thus distinctly improving hindlimb functional recovery of SCI rats and conferring superior therapeutic effect in coparison with other groups. Our work presented an effective and safe strategy for SCI targeting therapy. Besides, neuroprotective capacity of PEG deserves further investigation on other central nervous system diseases.

9.
Brain Res ; 1718: 75-82, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31054885

RESUMO

The molecular mechanisms underlying cervical spondylotic myelopathy (CSM) are poorly understood. To assess the correlation between HIF-1α, MMP-9 and functional recovery following chronic cervical spinal cord compression (CSCI). Rats in the sham group underwent C5 semi-laminectomy, while a water-absorbable polyurethane polymer was implanted into the C6 epidural space in the chronic CSCI group. Basso, Beattie and Bresnahan score and somatosensory evoked potentials were used to evaluate neurological function. Hematoxylin and eosin staining was performed to assess pathological changes in the spinal cord, while immunohistochemical analysis was used to examine HIF-1α and MMP-9 expression on days 7, 28, 42 and 70 post-surgery. Normal rats were only used for HE staining. The BBB score was significantly reduced on day 28 following CSCI, while SEPs exhibited decreased amplitude and increased latency. In chronic CSCI group, the BBB score and SEPs significantly improved on day 70 compared with day 28. HE staining revealed different level of spinal cord edema after chronic CSCI. Compared with the sham group, immunohistochemical analyses revealed that HIF-1α- and MMP-9-positive cells were increased on day 7 and peaked on day 28. HIF-1α and MMP-9 expression were demonstrated to be significantly positively correlated, whereas HIF-1α expression and BBB score were significantly negatively correlated, as well MMP-9 expression and BBB score. HIF-1α and MMP-9 expression are increased following chronic spinal cord compression and are positively correlated with one another. Decreased expression of HIF-1α and MMP-9 may contribute to functional recovery following CSCI. This expression pattern of HIF-1α and MMP-9 may give a new perspective on the molecular mechanisms of CSM.

10.
ACS Appl Mater Interfaces ; 11(25): 22429-22438, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31140774

RESUMO

Based on the high theoretical capacity and relatively high safety voltage, niobium-based oxides are regarded as promising intercalation-type electrode materials for advanced lithium-ion batteries (LIBs). Here, ZrNb14O37 nanowires are fabricated via a facile electrospinning method, presenting a nanoparticle-in-nanowire architecture. As an anode for LIBs, the as-fabricated ZrNb14O37 nanowires maintain a capacity of 244.9 mA h g-1 at 100 mA g-1 and present excellent cycling capability (0.026% of capacity fading per cycle during 1000 cycles) as well as outstanding rate performance. In situ X-ray diffraction measurement is conducted to understand the fundamental reaction mechanism during the lithiation/delithiation process. The ex situ observations, including X-ray photoelectron spectroscopy and transmission electron microscopy, are further performed to provide more lines of evidence of the reaction mechanism. Moreover, the excellent electrochemical performance of the full cell constructed using ZrNb14O37 nanowires and LiCoO2 suggests that ZrNb14O37 nanowires are a promising anode material. This work sheds new light on understanding the lithium storage mechanism and may open new opportunities to develop new anode materials for LIBs.

11.
Proc Natl Acad Sci U S A ; 116(20): 9820-9824, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31036653

RESUMO

Middle to Late Pleistocene human evolution in East Asia has remained controversial regarding the extent of morphological continuity through archaic humans and to modern humans. Newly found ∼300,000-y-old human remains from Hualongdong (HLD), China, including a largely complete skull (HLD 6), share East Asian Middle Pleistocene (MPl) human traits of a low vault with a frontal keel (but no parietal sagittal keel or angular torus), a low and wide nasal aperture, a pronounced supraorbital torus (especially medially), a nonlevel nasal floor, and small or absent third molars. It lacks a malar incisure but has a large superior medial pterygoid tubercle. HLD 6 also exhibits a relatively flat superior face, a more vertical mandibular symphysis, a pronounced mental trigone, and simple occlusal morphology, foreshadowing modern human morphology. The HLD human fossils thus variably resemble other later MPl East Asian remains, but add to the overall variation in the sample. Their configurations, with those of other Middle and early Late Pleistocene East Asian remains, support archaic human regional continuity and provide a background to the subsequent archaic-to-modern human transition in the region.

12.
Chemosphere ; 229: 169-180, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31078031

RESUMO

Although silver nanoparticles (AgNPs) are used in various commercial products, the biological effects of AgNPs on fish embryogenesis and the underlying molecular mechanisms are still poorly understood. In this study, both touch responses and neuron membrane potential were found to be abnormal in AgNPs-stressed embryos. Moreover, neurogenesis genes were unveiled to be down-regulated and were enriched in ligand-gated ion channel activity, dopamine receptor signaling pathway, etc. in AgNPs-stressed embryos by microarray assays. Additionally, the down-regulated expression of otpa/sncgb - gad1b/gad2 dopaminergic neurotransmitter genes, robo2 - vim and glrbb synaptic transmission genes, and motor neuron genes isl1 &isl2a was further identified in both AgNPs- and Ag+-stressed embryos by qPCR, whole-mount in situ hybridization (WISH), and by using specific promoter-derived GFP fluorescence transgenic zebrafish. Moreover, the reduced expression of gad1b, gad2, and isl1 could be recovered by adding Ag+ chelating compound l-cysteine in AgNPs stressed embryos. Our results reveal for the first time that it is through damaging the formation of neural circuits, including dopaminergic neurotransmitter, synaptic transmission, and motor activities, that AgNPs induce abnormal electrical membrane properties, leading to dysfunctional touch responses and locomotor escape responses mostly via their released Ag+ during embryogenesis.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Fenômenos Fisiológicos do Sistema Nervoso/efeitos dos fármacos , Prata/química , Prata/toxicidade , Tato/efeitos dos fármacos , Peixe-Zebra/embriologia , Animais , Embrião não Mamífero/fisiologia , Tato/fisiologia , Peixe-Zebra/metabolismo , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
13.
Exp Mol Pathol ; 110: 104255, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31028725

RESUMO

The 150-kDa oxygen-regulated protein (ORP150) belongs to a family of the heat shock protein implicated in the cellular response to environmental stress. Previous data demonstrated that ORP150 regulates the secretion of vascular endothelial growth factor (VEGF) to drive progression of angiogenesis associated with proliferative diabetic retinopathy. However, the expression and biological functions of serum ORP150 levels in diabetic nephropathy (DN) remain unclear. In this study, we reported for the first time that ORP150 was up-regulated in serum of patients with DN. Moreover, we observed the dramatic increase in serum ORP150 accompanied with the elevated levels of proteinuria and serum VEGF levels in DN, indicating the possible involvement of ORP150 in regulation of albuminuria via mediating VEGF in DN. Employing the streptozotocin (STZ) to construct the DN model, we confirmed the positive correlation of ORP150 with VEGF in vivo. Monoclonal anti-ORP150 antibodies treatment significantly decreased the secretion of VEGF and albuminuria in STZ-induced DN models. Consequently, our data suggested that ORP150 levels were positively correlated with proteinuria burden via mediating VEGF in DN. It may be considered as a novel diagnostic and therapeutic target.

14.
Int J Mol Sci ; 20(4)2019 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-30813425

RESUMO

Kaempferol (Kae) is a natural flavonoid with potent antioxidant activity, but its therapeutic use is limited by its low aqueous solubility. Here, a series of Kae derivatives were synthesized to improve Kae dissolution property in water and antioxidant activity. These compounds included sulfonated Kae (Kae-SO3), gallium (Ga) complexes with Kae (Kae-Ga) and Kae-SO3 (Kae-SO3-Ga). The compound structures were characterized by high-resolution mass spectrometry (HRMS), nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and thermal methods (TG/DSC). The results showed that a sulfonic group (-SO3) was successfully tethered on the C3' of Kae to form Kae-SO3. And in the metal complexation, 4-CO and 3-OH of the ligand participated in the coordination with Ga(III). The metal-to-ligand ratio 1:2 was suggested for both complexes. Interestingly, Kae-SO3-Ga was obviously superior to other compounds in terms of overcoming the poor water-solubility of free Kae, and the solubility of Kae-SO3-Ga was about 300-fold higher than that of Kae-Ga. Furthermore, the evaluation of antioxidant activities in vitro was carried out for Kae derivatives by using α,α-diphenyl-ß-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical scavenging. The results showed that Kae-SO3-Ga was also optimal for scavenging free radicals in a dose-dependent manner. These data demonstrate that sulfonate kaempferol-gallium complex has a promising future as a potential antioxidant and as a potential therapeutic agent for further biomedical studies.


Assuntos
Antioxidantes/farmacologia , Depuradores de Radicais Livres/farmacologia , Quempferóis/síntese química , Quempferóis/farmacologia , Água/química , Compostos de Bifenilo/química , Varredura Diferencial de Calorimetria , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Espectrometria de Massas , Picratos/química , Espectroscopia de Prótons por Ressonância Magnética , Solubilidade , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Ácidos Sulfônicos/química , Temperatura Ambiente , Termogravimetria
15.
ACS Appl Mater Interfaces ; 11(9): 9136-9143, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30763061

RESUMO

HTiNbO5 has been widely investigated in many fields because of its distinctive properties such as good redox activity, high photocatalytic activity, and environmental benignancy. Here, this work reports the synthesis of one-dimensional H0.92K0.08TiNbO5 nanowires via simple electrospinning followed by an ion-exchange reaction. The H0.92K0.08TiNbO5 nanowires consist of many small "lumps" with a uniform diameter distribution of around 150 nm. Used as an anode for lithium-ion batteries, H0.92K0.08TiNbO5 nanowires exhibit high capacity, fast electrochemical kinetics, and high performance of lithium-ion uptake. A capacity of 144.1 mA h g-1 can be carried by H0.92K0.08TiNbO5 nanowires at 0.5 C in the initial charge, and even after 150 cycles, the reversible capacity can remain at 123.7 mA h g-1 with an excellent capacity retention of 85.84%. For H0.92K0.08TiNbO5 nanowires, the diffusion coefficient of lithium ions is 1.97 × 10-11 cm2 s-1, which promotes the lithium-ion uptake effectively. The outstanding electrochemical performance is ascribed to its morphology and the formation of a stable phase during cycling. In addition, the in situ X-ray diffraction and ex situ transmission electron microscopy techniques are applied to reveal its lithium storage mechanism, which proves the structure stability and electrochemical reversibility, thus achieving high-performance lithium-ion uptake. All these advantages demonstrate that H0.92K0.08TiNbO5 nanowires can be a possible alternative anode material for rechargeable batteries.

16.
Phys Chem Chem Phys ; 21(4): 2006-2016, 2019 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-30633272

RESUMO

Thio-substituted nucleobases have received long-standing interest from experimental and theoretical scientists due to their potential applications in photodynamic therapy and crosslinking studies. Though the thymidine:4-thiothymidine dimer is an important structure in the DNA duplex, the molecular-level photoreaction mechanisms are still obscure. Herein, high-level QM/MM methods were adopted to investigate the photoinduced cycloaddition and (6-4) reactions of the thymidine:4-thiothymidine dimer in the DNA duplex, namely, d(ACCT(4ST)CGC:TGGAAGCG). Based on the calculated results, we identified five efficient nonadiabatic decay pathways to populate the T1 state from the initially occupied S2 state of Tp4ST via two crucial intersection structures, i.e., S2/S1 and S2/T2/S1/T1. Such photophysical processes are mainly localized on the 4-thiothymidine chromophore. After hopping to the T1 state, the light-induced [2+2] cycloaddition reaction could take place via a stepwise and nonadiabatic reaction pathway, which starts from Tp4ST via T1cc or T1cs intermediates in the T1 state and ends up with S5-thietane in the S0 state. By contrast, the concerted and thermal cycloaddition pathway in the ground state has a remarkable energy barrier, which is mechanistically less important. The subsequent generation of S5-(6-4) from S5-thietane is a concerted process in the S0 state with the simultaneous fission of the C4-S8 bond and the formation of the S8-H9 bond. In the end, we believe our present work will provide important mechanistic insights into photo-isomerization of thio-substituted nucleobases in DNA duplexes.


Assuntos
DNA/química , Timidina/análogos & derivados , Reação de Cicloadição , Dimerização , Modelos Químicos , Conformação de Ácido Nucleico , Timidina/química
17.
J Am Chem Soc ; 141(5): 2128-2134, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30633514

RESUMO

Among the Mo- and W-based two-dimensional (2D) transition metal dichalcogenides, MoTe2 is particularly interesting for phase-engineering applications, because it has the smallest free energy difference between the semiconducting 2H phase and metallic 1T' phase. In this work, we reveal that, under the proper circumstance, Mo and Te atoms can rearrange themselves to transform from a polycrystalline 1T' phase into a single-crystalline 2H phase in a large scale. We manifest the mechanisms of the solid-to-solid transformation by conducting density functional theory calculations, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The phase transformation is well described by the time-temperature-transformation diagram. By optimizing the kinetic rates of nucleation and crystal growth, we have synthesized a single-crystalline 2H-MoTe2 domain with a diameter of 2.34 mm, a centimeter-scale 2H-MoTe2 thin film with a domain size up to several hundred micrometers, and a seamless 1T'-2H MoTe2 coplanar homojunction. The 1T'-2H MoTe2 homojunction provides an elegant solution for ohmic contact of 2D semiconductors. The controlled solid-to-solid phase transformation in 2D limit provides a new route to realize wafer-scale single-crystalline 2D semiconductor and coplanar heterostructure for 2D circuitry.

18.
Plant Physiol Biochem ; 135: 404-410, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30635221

RESUMO

Cuticular wax is the main transpiration barrier against uncontrolled water loss for all aerial plant organs. This study presents water permeability and chemical composition of the cuticle on the petals and leaves of two cultivars of Rosa chinensis ('Movie star' and 'Tineke'). Numerous cultivar- and organ-specific differences, such as the water permeability and total cuticular wax, were detected among rose petals and leaves. Overall, the permeability to water is higher in petals than in leaves, varying between 1.8 × 10-5 m s-1 ('Tineke' leaves) and 1.0 × 10-4 m s-1 ('Tineke' petals). The cuticular wax coverage ranges from 4.9 µg cm-2 ('Tineke' petals) to 13.2 µg cm-2 ('Movie star' petals). The most prominent components of the waxes are n-alkanes with the odd-numbered chain lengths C27 and C29 in petals, and C31 and C33 in leaves. The lower water permeability of leaves is deduced to be associated with the higher weighted average chain length of their acyclic cuticular waxes. This study on transpiration via the cuticular wax barrier of the leaf and petal of rose provides further insight to link the chemical composition to the cuticular transpiration barrier properties.


Assuntos
Flores/química , Epiderme Vegetal/química , Folhas de Planta/química , Rosa/química , Ceras/química , Flores/metabolismo , Permeabilidade , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Transpiração Vegetal , Rosa/metabolismo , Água/metabolismo , Ceras/metabolismo
19.
Virology ; 528: 144-151, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30616204

RESUMO

A codon modification strategy was used to attenuate the avian pathogenicity of an oncolytic mesogenic Newcastle disease virus (NDV) by targeting the three major virulence factors: the fusion (F) protein, hemagglutinin neuraminidase (HN) and phosphoprotein (P). Recoding the F and HN genes with rare codons greatly reduced expression of both F and HN proteins and resulted in their low incorporation into virions. The F and HN recoded virus was partially attenuated in chickens even when the F protein cleavage site was modified. Full attenuation was achieved when the 5' portion of the P gene was recoded. The recoded P, F and HN triple gene mutant exhibited delayed cell death in human cancer cells with prolonged expression of a GFP transgene. While this engineered attenuated NDV strain has lower oncolytic potency, its capacity for prolonged transgene expression may allow its use as a vaccine or gene delivery vector.


Assuntos
Códon , Proteína HN/genética , Vírus da Doença de Newcastle/genética , Fosfoproteínas/genética , Proteínas Virais de Fusão/genética , Animais , Galinhas , Células HeLa , Humanos , Virulência/genética
20.
J Comput Chem ; 40(4): 657-670, 2019 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-30565268

RESUMO

Density functional theory (DFT) can be used to study the three-center two-electron (3c2e) bonding mode, which is universal in catalysts containing alkaline-earth (Ae) and boron-group (Bg) elements. However, because of the delocalization pattern of the 3c2e bond, the wavefunction cannot be accurately described by DFT methods. The calculated energies of Ae and Bg catalysts therefore fluctuate greatly when different functionals are used, largely because of inconsistent DFT-calculated binding energies of 3c2e bonds. Nevertheless, with the development of supercomputers and theoretical calculation software, the DFT method is becoming increasingly popular for studying Ae and Bg catalysts. In this study, we compared the performances of 21 functionals with the high-level composite G3B3 method in calculations for the binding energies of 3c2e bonds. Several frequently used post-Hartree-Fock methods were also tested. The calculation results indicate that the M06-2X, MN12-L, and MN15 functionals give consistent and reliable binding energies for common 3c2e bonds. © 2018 Wiley Periodicals, Inc.

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