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1.
J Orthop Surg Res ; 15(1): 58, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32075662

RESUMO

BACKGROUND: Pediatric femoral neck fracture is a rare injury but yields frequent complications. However, there is a paucity of data regarding the risk factors for these complications. PURPOSE: The present article reports the rate of complications after femoral neck fracture in pediatric patients and investigates the possible risk factors. METHODS: We retrospectively reviewed 44 children (mean age of 9.0 years, range from 2 to 14 years) who were surgically treated for femoral neck fracture in a single trauma center with a mean follow-up of 57.75 months (range from 11 to 224 months). Related clinical factors were recorded and analyzed by multivariable logistic regression. RESULTS: Fracture displacement or Delbet-type fracture had no relation to the injury mechanism. However, younger children experienced severe trauma, combined injury, and low fracture location more than older individuals did. Children with combined injuries were more likely to have a longer waiting time for surgical reduction. Common complications included avascular necrosis (AVN) in 14 cases, nonunion of fracture in 2 cases, coxa vara in 4 cases, and premature physeal closure (PPC) in 7 cases. Only the Delbet type was an independent predictor of AVN (OR = 0.14, p = 0.030). Inadequate reduction was associated with higher rates of coxa vara (OR = 33.19, p = 0.032). Epiphysis penetration in children younger than 10 years old increased the rate of PPC (p = 0.032). No significant risk factor was found for fracture nonunion. CONCLUSION: For femoral neck fracture in pediatric patients, both the injury mechanism and fracture characteristics have age-related distributions. Early reduction should be carried out as early as possible based on the safe condition of the child, but for younger children, transepiphyseal fixation should be avoided. AVN may be intrinsic to injury characteristics rather than resulting from the choice of treatment mode.

2.
Nutr Metab Cardiovasc Dis ; 29(12): 1418-1428, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31653519

RESUMO

BACKGROUND AND AIMS: Intrauterine growth restriction (IUGR) is a state of slower fetal growth usually followed by a catch-up growth. Postnatal catch-up growth in IUGR models increases the incidence of pulmonary arterial hypertension in adulthood. Here, we hypothesize that the adverse pulmonary vascular consequences of IUGR may be improved by slowing down postnatal growth velocity. Meanwhile, cognitive function was also studied. METHODS AND RESULTS: We established an IUGR rat model by restricting maternal food throughout gestation. After birth, pups were fed a regular or restricted diet during lactation by changing litter size. Thus, there were three experimental groups according to the dam/offspring diet: C/C (gold standard), IUGR with catch-up growth (R/C) and IUGR with delayed growth (R/D). In adulthood (14 weeks of age), we assessed pulmonary vascular development by hemodynamic measurement and immunohistochemistry. Our results showed that adult R/C offspring developed an elevated mean pulmonary arterial pressure (mPAP) and pulmonary arteriolar remodeling accompanied with decreased eNOS mRNA and protein expressions compared to C/C or R/D offspring. This suggested that delayed postnatal growth improved pulmonary circulation compared to postnatal catch-up growth. Conversely, adult R/D offspring performed poorly in cognition. Behavior test and electrophysiology results exhibited a reduced synaptic plasticity. Furthermore, decreased mRNA expression levels of the memory-related gene zif268 and transcription factor recruitment factor p300 in the hippocampus region were also observed in R/D group. CONCLUSION: These findings indicate that delayed postnatal growth results in cognitive impairment, but it reverses elevations in mPAP induced by postnatal catch-up growth following IUGR.


Assuntos
Comportamento Animal , Encéfalo/crescimento & desenvolvimento , Restrição Calórica/efeitos adversos , Cognição , Disfunção Cognitiva/etiologia , Retardo do Crescimento Fetal/dietoterapia , Hipertensão Pulmonar/prevenção & controle , Artéria Pulmonar/crescimento & desenvolvimento , Fatores Etários , Fenômenos Fisiológicos da Nutrição Animal , Animais , Encéfalo/metabolismo , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/fisiopatologia , Disfunção Cognitiva/psicologia , Modelos Animais de Doenças , Proteína p300 Associada a E1A/genética , Proteína p300 Associada a E1A/metabolismo , Proteína 1 de Resposta de Crescimento Precoce/genética , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Feminino , Retardo do Crescimento Fetal/fisiopatologia , Retardo do Crescimento Fetal/psicologia , Hemodinâmica , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/metabolismo , Hipertensão Pulmonar/fisiopatologia , Masculino , Plasticidade Neuronal , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Artéria Pulmonar/metabolismo , Ratos Sprague-Dawley , Remodelação Vascular , Ganho de Peso
3.
Hypertension ; 74(5): 1160-1171, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31596625

RESUMO

Intrauterine life represents a window of phenotypic plasticity which carries consequences for later health in adulthood as well as health of subsequent generations. Intrauterine growth-restricted fetuses (intrauterine growth restriction [IUGR]) have a higher risk of pulmonary arterial hypertension in adulthood. Endothelial dysfunction, characterized by hyperproliferation, invasive migration, and disordered angiogenesis, is a hallmark of pulmonary arterial hypertension pathogenesis. Growing evidence suggests that intergenerational transmission of disease, including metabolic syndrome, can be induced by IUGR. Epigenetic modification of the paternal germline is implicated in this transmission. However, it is unclear whether offspring of individuals born with IUGR are also at risk of developing pulmonary arterial hypertension and endothelial dysfunction. Using a model of maternal caloric restriction to induce IUGR, we found that first and second generations of IUGR exhibited elevated pulmonary arterial pressure, myocardial, and vascular remodeling after prolonged exposure to hypoxia. Primary pulmonary vascular endothelial cells (PVECs) from both first and second generations of IUGR exhibited greater proliferation, migration, and angiogenesis. Moreover, in 2 generations, PVECs-derived ET-1 (endothelin-1) was activated by IUGR and hypoxia, and its knockdown mitigated PVECs dysregulation. Most interestingly, within ET-1 first intron, reduced DNA methylation and enhanced tri-methylation of lysine 4 on histone H3 were observed in PVECs and sperm of first generation of IUGR, with DNA demethylation in PVECs of second generation of IUGR. These results suggest that IUGR permanently altered epigenetic signatures of ET-1 from the sperm and PVECs in the first generation, which was subsequently transferred to PVECs of offspring. This mechanism would yield 2 generations with endothelial dysfunction and pulmonary arterial hypertension-like pathophysiological features in adulthood.


Assuntos
Epigênese Genética , Retardo do Crescimento Fetal/genética , Predisposição Genética para Doença , Hipertensão Pulmonar/genética , Prenhez , Animais , Western Blotting , Proliferação de Células/genética , Metilação de DNA , Modelos Animais de Doenças , Células Endoteliais , Feminino , Retardo do Crescimento Fetal/fisiopatologia , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Hipertensão Pulmonar/fisiopatologia , Masculino , Gravidez , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Sensibilidade e Especificidade , Espermatozoides
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 216: 98-104, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-30884353

RESUMO

In order to characterize molecular structure changes of drugs upon co-crystallization by means of spectroscopic techniques, vibrational spectra of solid-state diflunisal (DIF), isonicotinamide (ISO) and their 2:1 co-crystal have been investigated by using terahertz time-domain spectroscopy (THz-TDS) and Raman spectroscopy. A 2:1 DIF-ISO co-crystal between DIF and ISO has been synthesized by slow solution crystallization from ethanol. The experimental THz spectroscopy shows that the co-crystal has a few significantly different absorption peaks compared with raw parent materials within the frequency region from 0.2 to 1.6 THz. Likewise, some differences of vibrational spectra between the co-crystal and starting compounds could also be characterized by Raman spectral results. Density functional theory (DFT) was used to simulate optimized structures and vibrational modes of two kind of possible co-crystal theoretical forms (form I and II) between DIF and ISO. Theoretical co-crystal form I is shown with 2:1 theoretical binary-adduct formed by carboxylic acid-amide and carboxylic acid-pyridine under inter-molecular hydrogen bonding. Theoretical co-crystal form II has a similar structure as form I, meanwhile the only difference is that O63 atom simultaneously forms hydrogen bond with H33 and H64. Also the hydroxyl -OH and carboxyl group -COOH establish molecular heterocycle under intra-molecular hydrogen bonds in both forms. The theoretical results show that both THz and Raman spectra of co-crystal form II between DIF and ISO is more consistent with the experimental observations than those of co-crystal form I. These results provide us with a wealth of information and unique method for characterizing the composition of co-crystal structures and also inter-molecular hydrogen bonding interactions shown within pharmaceutical co-crystallization at the molecular level.

5.
Pharmaceutics ; 11(2)2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30704026

RESUMO

The co-crystallization of active pharmaceutical ingredients (APIs) has received increasing attention due to the modulation of the relative physicochemical properties of APIs such as low solubility, weak permeability and relatively inferior oral bioavailability. Crystal engineering plays a decisive role in the systematic design and synthesis of co-crystals by means of exerting control on the inter-molecular interactions. The characterization and detection of such co-crystal formations plays an essential role in the field of pharmaceutical research and development. In this work, nitrofurantoin (NF), melamine (MELA) and their hydrated co-crystal form were characterized and analyzed by using terahertz time-domain spectroscopy (THz-TDS) and Raman vibrational spectroscopy. According to the experimental THz spectra, the hydrated co-crystal form has characteristic absorption peaks at 0.67, 1.05, 1.50 and 1.73 THz, while the THz spectra for the two raw parent materials (NF and MELA) are quite different within this spectral region. Similar observations were made from the experimental Raman vibrational spectra results. Density functional theory (DFT) calculation was performed to help determine the major vibrational modes of the hydrated co-crystal between nitrofurantoin and melamine, as well as identify the structural changes due to inter- and/or intra-molecular hydrogen bonding motifs between NF and MELA. The results of the theoretical frequency calculations corroborate the THz and Raman experimental spectra. The characteristic bands of the NF⁻MELA-hydrated co-crystal between nitrofurantoin and melamine were also determined based on the DFT simulated calculation. The reported results in this work provide us with a wealth of structural information and a unique vibrational spectroscopic method for characterizing the composition of specific co-crystals and inter-molecular hydrogen bonding interactions upon pharmaceutical co-crystallization.

6.
J Am Heart Assoc ; 8(2): e010456, 2019 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-30636484

RESUMO

Background Intrauterine growth retardation ( IUGR ) is related to pulmonary artery hypertension in adults, and mi croRNA -206 (miR-206) is proposed to affect the proliferation and apoptosis of pulmonary artery smooth muscle cells ( PASMC s) via post-transcriptional regulation. Methods and Results In an IUGR rat model, we found that the expression and function of potassium voltage-gated channel subfamily A member 5 (Kv1.5) in PASMC s was inhibited, and pulmonary artery hypertension was exaggerated after chronic hypoxia ( CH ) treatment as adults. micro RNA expression was investigated in PASMC s from 12-week-old male IUGR rats with CH by microarray, polymerase chain reaction, and in situ hybridization. The expression levels of Kv1.5 in primary cultured PASMC s and pulmonary artery smooth muscle from IUGR or control rats were evaluated with and without application of an miR-206 inhibitor. Right ventricular systolic pressure, cell proliferation, luciferase reporter assay, and IK v were also calculated. We found increased expression of miR-206 in resistance pulmonary arteries of IUGR rats at 12 weeks compared with newborns. Application of an miR-206 inhibitor in vivo or in vitro increased expression of Kv1.5 α-protein and KCNA 5. Also, decreased right ventricular systolic pressure and cell proliferation were observed in PASMC s from 12-week-old control and IUGR rats after CH , while inhibitor did not significantly affect control and IUGR rats. Conclusions These results suggest that expression of Kv1.5 and 4-aminopyridine (Kv channel special inhibitor)-sensitive Kv current were correlated with the inhibition of miR-206 in PA rings of IUGR - CH rats and cultured IUGR PASMC s exposed to hypoxia. Thus, miR-206 may be a trigger for induction of exaggerated CH-pulmonary artery hypertension of IUGR via Kv1.5.


Assuntos
Retardo do Crescimento Fetal/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Hipertensão Pulmonar/genética , Canal de Potássio Kv1.5/genética , MicroRNAs/genética , Músculo Liso Vascular/metabolismo , Animais , Animais Recém-Nascidos , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Retardo do Crescimento Fetal/patologia , Hipertensão Pulmonar/etiologia , Hipertensão Pulmonar/metabolismo , Hibridização In Situ , Canal de Potássio Kv1.5/biossíntese , MicroRNAs/biossíntese , Análise em Microsséries , Músculo Liso Vascular/patologia , Artéria Pulmonar/metabolismo , Artéria Pulmonar/patologia , Artéria Pulmonar/fisiopatologia , RNA/genética , Ratos , Resistência Vascular/fisiologia
7.
Nanoscale ; 11(15): 7111-7116, 2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30644935

RESUMO

The controlled construction of organic heterostructured architectures derived from molecules with similar nucleation thresholds and concentrations has been rare and remains a great challenge. Herein, we report a sequential epitaxial growth to synthesize dual-color-emitting organic heterostructures with 9,10-bis(phenylethynyl)anthracene (BPEA) microwire trunks and tris-(8-hydroxyquinoline)aluminium (Alq3) microstructure branches by an anti-solvent induced sequential crystallization strategy. During the epitaxial growth process, the hydrogen-bonding interactions of the anti-solvent and solvent cause a large change in the solubility and crystallization rate of BPEA and Alq3 molecules in the mixed system, which facilitates sequential crystallization of organic molecule pairs with similar nucleation thresholds and concentrations into desired heterostructures by manipulating the synergism of anti-solvents and solvents. The Förster resonant energy transfer process in heterostructures could be modulated by varying the structure of heterostructures, such as the shape, amount and angles of the branches. The present synthesis strategy provides a unique insight into the detailed formation mechanism of complex organic heterostructures, further guiding the construction of more functional heterostructure materials.

8.
Ann Thorac Surg ; 107(1): e23-e25, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29944878

RESUMO

A 26-year-old woman with a diagnosis of congenital heart disease was admitted to the hospital with exertional dyspnea, cyanotic complexion, and bilateral lower limb edema. All tests revealed isolated severe right ventricular hypertrophy. She was in poor condition, with a diminishing chance for routine surgical treatment, so she was scheduled for orthotopic homologous heart transplantation. After the operation, isolated severe right ventricular hypertrophic cardiomyopathy was confirmed histologically and pathologically. After the operation, the patient's cardiac function was normal. Exertional dyspnea, cyanotic complexion, and bilateral lower limb edema all improved postoperatively.


Assuntos
Ecocardiografia , Hipertrofia Ventricular Direita/diagnóstico por imagem , Adulto , Tamponamento Cardíaco/etiologia , Erros de Diagnóstico , Dispneia/etiologia , Anomalia de Ebstein/diagnóstico , Edema/etiologia , Emergências , Feminino , Transplante de Coração , Humanos , Hipertrofia Ventricular Direita/complicações , Hipertrofia Ventricular Direita/patologia , Hipertrofia Ventricular Direita/cirurgia , Imagem por Ressonância Magnética , Derrame Pericárdico/etiologia
9.
Mater Sci Eng C Mater Biol Appl ; 94: 376-384, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30423720

RESUMO

Titanium and titanium alloys have been widely used as dental and orthopedic materials. The infection and the bacterium influenced corrosion both are concerned problems. Ti-3Cu alloy exhibits strong antibacterial properties against E. coli and S. aureus. The strong antibacterial properties of Ti-3Cu provides with a potential new method to reduce the bacterium influenced corrosion. S. aureus suspension was selected to simulate a serious bacterial condition. The corrosion behavior of Ti-3Cu alloy in S. aureus suspension was investigated by an electrochemical testing and an immersion test in comparison with pure titanium. Electrochemical results showed that Ti-3Cu exhibited a much better anti-corrosion property than cp-Ti in S. aureus suspension. Surface observation demonstrated that no corrosion pit was observed on Ti-3Cu alloy after 30 days immersion in the suspension while lots of corrosion pits were found on cp-Ti. The biofilm formation on the surface was observed by scanning electronic microscopy (SEM) in different periods. It has been revealed that S. aureus could grow and gather on the surface of cp-Ti to form biofilm after 18 h immersion, but only several bacteria were found on Ti-3Cu alloy even after 24 h immersion, displaying that Ti-3Cu alloy exhibits very strong anti-adhesion properties against S. aureus. It was concluded that Ti-3Cu performs a super anti-corrosion property due to the strong anti-adhesion property, in which Ti2Cu precipitate plays a critical role.


Assuntos
Ligas/farmacologia , Antibacterianos/farmacologia , Tecnologia Biomédica/métodos , Staphylococcus aureus/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Biofilmes , Ensaio de Unidades Formadoras de Colônias , Corrosão , Técnicas Eletroquímicas , Íons , Testes de Sensibilidade Microbiana , Propriedades de Superfície , Suspensões
10.
J Orthop Surg Res ; 13(1): 218, 2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-30165867

RESUMO

BACKGROUND: Osteomyelitis (OM) is an uncommon disease that originates from many different mechanisms in children. Treatment often involves a combination of surgical debridement combined and antibiotic therapy. The purpose of this article is to evaluate the effect of debridement combined with a new resorbable bone graft substitute (RBGS) mixed with antibiotics in the treatment of infants with OM. METHODS: Twenty-two patients diagnosed with OM at our institution underwent debridement combined with implantation of RBGS mixed with vancomycin within 48 h after admission. Clinical and epidemiological factors, preoperative and postoperative radiographs, and laboratory parameters, including white blood cell (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and neutrophil percentage (NEU%), were documented. The function of the involved extremity was evaluated at the final follow-up. RESULTS: The mean age was 6.3 ± 4.8 months (range, 0.5 to 12 months). The mean duration of the symptoms was 14.5 ± 8.4 days (range, 2 to 30 days). The average length of hospitalization was 13.7 ± 6.2 days (range, 6 to 28 days). 13.64% (3/22) had positive results of purulent material obtained at the time of open biopsy and 18.18% (4/22) had positive blood cultures. The most common sites were located in the proximal femur (12), the distal femur (3), and the proximal humerus (3). Ten patients presented with concurrent pyogenic arthritis, while another 12 infants suffered from simple isolated hematogenous OM. The mean follow-up time was 3.0 ± 1.6 years (range, 1.0 to 6.0 years). Seven of 22 patients (31.82%) had complications such as limb length deformity (LLD), avascular necrosis (AVN), and pathologic subluxation of the hip. Fifteen out of 22 (68.18%) patients achieved good results. Additionally, patients who had concomitant pyogenic arthritis were more likely to develop complications than those with isolated OM (p = 0.02). CONCLUSIONS: Early debridement combined with implantation of RBGS mixed with vancomycin in the treatment of infants with OM achieved acceptable results in this series. Compared to those with simple isolated OM, patients with secondary pyogenic arthritis had a more virulent course.


Assuntos
Antibacterianos , Substitutos Ósseos , Desbridamento , Osteomielite , Antibacterianos/uso terapêutico , Substitutos Ósseos/uso terapêutico , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Osteomielite/terapia , Estudos Retrospectivos
11.
Nanoscale ; 10(23): 11006-11012, 2018 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-29868653

RESUMO

Directing the architecture of complex organic nanostructures is desirable and still remains a challenge in areas of materials science due to their structure-dependent collective optoelectronic properties. Herein, we demonstrate a simple and versatile solution strategy that allows surface tension to drive low-dimensional nanostructures to aggregate into complex structures via a lab in a droplet technique. By selecting a suitable combination of a solvent and an anti-solvent with controllable surface tension difference, the droplets can be automatically cracked into micro-droplets, which provides an aggregation force directed toward the centre of the droplet to drive the low-dimensional building blocks to form the special aggregations during the self-assembly process. This synthetic strategy has been shown to be universal for organic materials, which is beneficial for further optimizing the optoelectronic properties. These results contribute to gaining an insightful understanding on the detailed growth mechanism of complex organic nanostructures and greatly promoting the development of organic nanophotonics.

12.
Front Pharmacol ; 9: 241, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29615911

RESUMO

Recent advances in epigenetics have made a tremendous impact on our knowledge of biological phenomena and the environmental stressors on complex diseases. Understanding the mechanism of epigenetic reprogramming during the occurrence of pulmonary hypertension (PH) is important for advanced studies and clinical therapy. In this article, we review the discovery of novel epigenetic mechanisms associated with PH including DNA methylation, histone modification, and noncoding RNA interference. In addition, we highlight the role of epigenetic mechanisms in adult PAH resulting from undesirable perinatal environments-Extrauterine growth restriction (EUGR) and Intrauterine growth retardation (IUGR). Lastly, we give a comprehensive summary for the remaining challenges and discuss future methods of epigenetic targeted therapy for pulmonary hypertension.

13.
Int J Low Extrem Wounds ; 17(2): 130-132, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29577794

RESUMO

A 2-year-old girl who was badly injured by a forklift, was presented to the emergency department with open and comminuted pelvic fracture, dislocation of right sacroiliac jointand femoral neck fracture on the left side. An urgent debridement was performed. However, postoperatively, the girl had apparent abdominal distension. The results of contrast-enhanced CT implied that the intestineherniated through the fissure formed by dislocation of the sacroiliac joint, which was confirmed during the operation. Therefore, hernia repair and reduction of the sacroiliac joint were performed by a Multidisciplinary team.With regard to patient's age, the sacroiliac joint was reduced and sutured with two absorbable anchors. The fracture healed in the following 3 months after discharge.


Assuntos
Amputação/métodos , Fixação Interna de Fraturas/métodos , Fraturas Ósseas , Hérnia , Herniorrafia/métodos , Ossos Pélvicos , Trombose/cirurgia , Pré-Escolar , Feminino , Fraturas Ósseas/diagnóstico , Fraturas Ósseas/cirurgia , Hérnia/diagnóstico , Hérnia/etiologia , Humanos , Ossos Pélvicos/lesões , Ossos Pélvicos/cirurgia , Pelve/diagnóstico por imagem , Pelve/cirurgia , Articulação Sacroilíaca/lesões , Articulação Sacroilíaca/cirurgia , Trombose/etiologia , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
14.
Inorg Chem ; 57(7): 4098-4103, 2018 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-29561597

RESUMO

Doping has been a reliable way to improve the properties of black phosphorus (BP). However, a uniform and large amount of doping in BP remains a challenge. Herein, the synthesis of tellurium-doped black phosphorus (Te-doped BP) single crystals with high crystalline quality is achieved by the chemical vapor transport reaction method. The synthetic route enables a uniform and relatively large amount (up to 0.5% atomic ratio) of Te-doping in BP single crystals. The electrocatalytic oxygen evolution reaction (OER) properties of few-layer Te-doped BP nanosheets prepared by liquid exfoliation were also investigated for the first time. Electrochemical tests demonstrated that the OER onset-potential of undoped and Te-doped BP nanosheets was 1.63 and 1.49 V, respectively. The result implies that doping provides an effective route to enhance the electrochemical OER performance of BP.

15.
IEEE Trans Pattern Anal Mach Intell ; 40(5): 1209-1223, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28541893

RESUMO

We are motivated by the need for a generic object proposal generation algorithm which achieves good balance between object detection recall, proposal localization quality and computational efficiency. We propose a novel object proposal algorithm, BING++, which inherits the virtue of good computational efficiency of BING [1] but significantly improves its proposal localization quality. At high level we formulate the problem of object proposal generation from a novel probabilistic perspective, based on which our BING++ manages to improve the localization quality by employing edges and segments to estimate object boundaries and update the proposals sequentially. We propose learning the parameters efficiently by searching for approximate solutions in a quantized parameter space for complexity reduction. We demonstrate the generalization of BING++ with the same fixed parameters across different object classes and datasets. Empirically our BING++ can run at half speed of BING on CPU, but significantly improve the localization quality by 18.5 and 16.7 percent on both VOC2007 and Microhsoft COCO datasets, respectively. Compared with other state-of-the-art approaches, BING++ can achieve comparable performance, but run significantly faster.

16.
Hereditas ; 155: 4, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28690479

RESUMO

BACKGROUND: Osteoarthritis (OA) is one of the most prevalent chronic joint diseases while the precise genetic mechanism remains elusive. In this study, we investigated the gene expression profile in OA by microarray analysis. RESULTS: Histopathological characteristics of OA cartilage were examined using a rat model of leptin-induced OA. Gene expression profile of leptin-induced articular cartilage and healthy rat cartilage were compared using genome-wide microarray hybridization. A total of 1857 genes differentially expressed genes (1197 upregulated and 660 downregulated) were identified, some of which are known to be associated with leptin-induced OA phenotype. These included genes related to MMPs, inflammatory factors, growth factors, apoptotic genes and osteogenic genes. In addition, upregulated expressions of some new candidate genes, which have hitherto fore not been linked to OA (such as BCL2L11) were detected in leptin-induced OA cartilage, which suggests that these genes might be important for OA molecular mechanism. CONCLUSION: Our findings suggest that pathogenesis of leptin-induced OA involves modulation of expression of multiple genes, although the underlying molecular mechanisms need to be studied further. Further investigation of leptin-induced gene expression changes is needed to gain new insights into the molecular mechanism of OA pathogenesis.


Assuntos
Cartilagem Articular/metabolismo , Osteoartrite do Joelho/genética , Transcriptoma , Animais , Articulação do Joelho/patologia , Leptina , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Osteoartrite do Joelho/induzido quimicamente , Ratos , Ratos Sprague-Dawley , Transdução de Sinais
17.
Nanotechnology ; 28(42): 424001, 2017 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-28825413

RESUMO

Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

18.
Small ; 13(32)2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28696584

RESUMO

A systematic cytotoxicity study of layered black phosphorus (BP) is urgently needed before moving forward to its potential biomedical applications. Herein, bulk BP crystals are synthesized and exfoliated into layered BP with different lateral size and thickness. The cytotoxicity of as-exfoliated layered BP is evaluated by a label-free real-time cell analysis technique, displaying a concentration-, size-, and cell type-dependent response. The IC50 values can vary by 40 and 30 times among the BP sizes and cell types, respectively. BP-1 with the largest lateral size and thickness has the highest cytotoxicity; whereas the smallest BP-3 only shows moderate toxicity. The sensitivity of three tested cell lines follows the sequence of 293T > NIH 3T3 > HCoEpiC. Two possible mechanisms for BP to induce cytotoxicity are proposed and verified: (1) the generation of intracellular reactive oxygen species (ROS) is detected by a ROS sensitive probe using the inverted fluorescence microscopy and flow cytometry; (2) the interaction of layered BP and model cell membrane is examined by quartz crystal microbalance with dissipation, illustrating the disruption of cell membrane integrity especially by the largest BP-1. This systematic study of BP's cytotoxicity will shed light on its future biomedical and environmental applications.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Fósforo/farmacologia , Animais , Citometria de Fluxo , Células HEK293 , Humanos , Camundongos , Microscopia de Fluorescência , Células NIH 3T3 , Fósforo/química
19.
PLoS One ; 12(5): e0177270, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28486510

RESUMO

The transfer of an acetyl group from acetyl-CoA to an acceptor amine is a ubiquitous biochemical transformation catalyzed by Gcn5-related N-acetyltransferases (GNATs). Although it is established that the reaction proceeds through a sequential ordered mechanism, the role of the acetyl group in driving the ordered formation of binary and ternary complexes remains elusive. Herein, we show that CoA and acetyl-CoA alter the conformation of the substrate binding site of an arylalkylamine N-acetyltransferase (AANAT) to facilitate interaction with acceptor substrates. However, it is the presence of the acetyl group within the catalytic funnel that triggers high affinity binding. Acetyl group occupancy is relayed through a conserved salt bridge between the P-loop and the acceptor binding site, and is manifested as differential dynamics in the CoA and acetyl-CoA-bound states. The capacity of the acetyl group carried by an acceptor to promote its tight binding even in the absence of CoA, but also its mutually exclusive position to the acetyl group of acetyl-CoA underscore its importance in coordinating the progression of the catalytic cycle.


Assuntos
Arilalquilamina N-Acetiltransferase/metabolismo , Catálise
20.
Biomol NMR Assign ; 11(1): 105-109, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28236225

RESUMO

Arylalkylamine N-acetyltransferases (AANATs) catalyze the transfer of an acetyl group from the acetyl-group donor, acetyl-CoA, to an arylalkylamine acceptor. Although a single AANAT has been identified in mammals, insects utilize multiple AANATs in a diverse array of biological processes. AANATs belong to the GCN5-related acetyltransferase (GNAT) superfamily of enzymes, which despite their overall very low sequence homology, are characterized by a well conserved catalytic core domain. The structural properties of many GNATs have been extensively studied by X-ray crystallography that revealed common features during the catalytic cycle. Here we report the 1H, 13C and 15N backbone NMR resonance assignment of the 24 kDa AANAT3 from Bombyx mori (bmAANAT3) as a first step towards understanding the role of protein dynamics in the catalytic properties of AANATs. Our preliminary solution NMR studies reveal that bmAANAT3 is well-folded in solution. The P-loop, which is responsible for cofactor binding, is flexible in the free-state, while a large region of the enzyme interconverts between two distinct conformations in the slow exchange regime.


Assuntos
Arilalquilamina N-Acetiltransferase/química , Arilalquilamina N-Acetiltransferase/metabolismo , Bombyx/enzimologia , Ressonância Magnética Nuclear Biomolecular , Animais , Biocatálise , Modelos Moleculares , Conformação Proteica
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