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Grain and flag leaf size are two important agronomic traits that influence grain yield in rice (Oryza sativa). Many QTLs and genes that regulate these traits individually have been identified, however, few QTLs and genes that simultaneously control these two traits have been identified. In this study, we conducted a genome-wide association analysis in rice and detected a major locus, WIDTH OF LEAF AND GRAIN (WLG), that associated with both grain and flag leaf width. WLG encodes a RING-domain E3 ubiquitin ligase. WLGhap.B, which possesses five SNP variations compared to WLGhap.A, encodes a protein with enhanced ubiquitination activity that confers increased rice leaf width and grain size, whereas mutation of WLG leads to narrower leaves and smaller grains. Both WLGhap.A and WLGhap.B interact with LARGE2, a HETC-type E3 ligase, however, WLGhap.B exhibits stronger interaction with LARGE2, thus higher ubiquitination activity towards LARGE2 compared with WLGhap.A. Lysine1021 is crucial for the ubiquitination of LARGE2 by WLG. Loss-of-function of LARGE2 in wlg-1 phenocopies large2-c in grain and leaf width, suggesting that WLG acts upstream of LARGE2. These findings reveal the genetic and molecular mechanism by which the WLG-LARGE2 module mediates grain and leaf size in rice, and suggest the potential of WLGhap.B in improving rice yield.
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Maize is one of the world's most important staple crops, yet its production is increasingly threatened by the rising frequency of high-temperature stress (HTS). To investigate the genetic basis of anther thermotolerance under field conditions, we performed linkage and association analysis to identify HTS response quantitative trait loci (QTL) using three recombinant inbred line (RIL) populations and an association panel containing 375 diverse maize inbred lines. These analyses resulted in the identification of 16 co-located large QTL intervals. Among the 37 candidate genes identified in these QTL intervals, five have rice or Arabidopsis homologs known to influence pollen and filament development. Notably, one of the candidate genes, ZmDUP707, has been subject to selection pressure during breeding. Its expression is suppressed by HTS, leading to pollen abortion and barren seeds. We also identified several additional candidate genes potentially underly QTL previously reported by other researchers. Taken together, our results provide a pool of valuable candidate genes that could be employed by future breeding programs aiming at enhancing maize HTS tolerance.
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Locos de Características Quantitativas , Termotolerância , Zea mays , Zea mays/genética , Zea mays/fisiologia , Locos de Características Quantitativas/genética , Termotolerância/genética , Ligação Genética , Mapeamento Cromossômico , Genes de Plantas/genética , Flores/genética , Flores/fisiologia , Pólen/genética , Pólen/fisiologiaRESUMO
Grain chalkiness is an undesirable trait that negatively regulates grain yield and quality in rice. However, the regulatory mechanism underlying chalkiness is complex and remains unclear. We identified a positive regulator of white-belly rate (WBR). The WBR7 gene encodes sucrose synthase 3 (SUS3). A weak functional allele of WBR7 is beneficial in increasing grain yield and quality. During the domestication of indica rice, a functional G/A variation in the coding region of WBR7 resulted in an E541K amino acid substitution in the GT-4 glycosyltransferase domain, leading to a significant decrease in decomposition activity of WBR7A (allele in cultivar Jin23B) compared with WBR7G (allele in cultivar Beilu130). The NIL(J23B) and knockout line NIL(BL130)KO exhibited lower WBR7 decomposition activity than that of NIL(BL130) and NIL(J23B)COM, resulting in less sucrose decomposition and metabolism in the conducting organs. This caused more sucrose transportation to the endosperm, enhancing the synthesis of storage components in the endosperm and leading to decreased WBR. More sucrose was also transported to the anthers, providing sufficient substrate and energy supply for pollen maturation and germination, ultimately leading to an increase rate of seed setting and increased grain yield. Our findings elucidate a mechanism for enhancing rice yield and quality by modulating sucrose metabolism and allocation, and provides a valuable allele for improved rice quality.
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Grain size is a crucial agronomic trait that affects stable yield, appearance, milling quality, and domestication in rice. However, the molecular and genetic relationships among QTL genes (QTGs) underlying natural variation for grain size remain elusive. Here, we identified a novel QTG SGW5 (suppressor of gw5) by map-based cloning using an F2 segregation population by fixing same genotype of the master QTG GW5. SGW5 positively regulates grain width by influencing cell division and cell size in spikelet hulls. Two nearly isogenic lines exhibited a significant differential expression of SGW5 and a 12.2% increase in grain yield. Introducing the higher expression allele into the genetic background containing the lower expression allele resulted in increased grain width, while its knockout resulted in shorter grain hulls and dwarf plants. Moreover, a cis-element variation in the SGW5 promoter influenced its differential binding affinity for the WRKY53 transcription factor, causing the differential SGW5 expression, which ultimately leads to grain size variation. GW5 physically and genetically interacts with WRKY53 to suppress the expression of SGW5. These findings elucidated a new pathway for grain size regulation by the GW5-WRKY53-SGW5 module and provided a novel case for generally uncovering QTG interactions underlying the genetic diversity of an important trait in crops.
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Grão Comestível , Regulação da Expressão Gênica de Plantas , Oryza , Proteínas de Plantas , Locos de Características Quantitativas , Oryza/genética , Oryza/anatomia & histologia , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Locos de Características Quantitativas/genética , Grão Comestível/genética , Grão Comestível/anatomia & histologia , Grão Comestível/crescimento & desenvolvimento , Genes de Plantas , Regiões Promotoras Genéticas/genética , Alelos , Fenótipo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/anatomia & histologia , Ligação ProteicaRESUMO
A class I PCF type protein, TCP4, was identified as a transcription factor associated with both grain size and tillering through a DNA pull-down-MS assay combined with a genome-wide association study. This transcription factor was found to have a significant role in the variations among the 533 rice accessions, dividing them into two main subspecies. A Tourist-like miniature inverted-repeat transposable element (MITE) was discovered in the promoter of TCP4 in japonica/geng accessions (TCP4M+), which was found to suppress the expression of TCP4 at the transcriptional level. The MITE-deleted haplotype (TCP4M-) was mainly found in indica/xian accessions. ChIP-qPCR and EMSA demonstrated the binding of TCP4 to promoters of grain reservoir genes such as SSIIa and Amy3D in vivo and in vitro, respectively. The introduction of the genomic sequence of TCP4M+ into different TCP4M- cultivars was found to affect the expression of TCP4 in the transgenic rice, resulting in decreased expression of its downstream target gene SSIIa, increased tiller number, and decreased seed length. This study revealed that a Tourist-like MITE contributes to subspecies divergence by regulating the expression of TCP4 in response to environmental pressure, thus influencing source-sink balance by regulating starch biosynthesis in rice.
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Elementos de DNA Transponíveis , Oryza , Elementos de DNA Transponíveis/genética , Oryza/genética , Estudo de Associação Genômica Ampla , Regiões Promotoras Genéticas/genética , Grão Comestível/genética , Fatores de Transcrição/genéticaRESUMO
BACKGROUND: The temporomandibular joint (TMJ) disc is a critical fibrocartilaginous structure with limited regenerative capacity in the oral system. Perforation of the TMJ disc can lead to osteoarthritis and ankylosis of the TMJ because of the lack of disc protection. Clinical treatments for TMJ disc perforation, such as discectomy, hyaluronic acid injection, endoscopic surgery and high position arthroplasty of TMJ, are questionable with regard to long-term outcomes, and only three fourths of TMJ disc perforations are repairable by surgery, even in the short-term. Tissue engineering offers the potential for cure of repairable TMJ disc perforations and regeneration of unrepairable ones. OBJECTIVES: This review discusses the classification of TMJ disc perforation and defines typical TMJ disc perforation. Advancements in the engineering-based repair of TMJ disc perforation by stem cell therapy, construction of a disc-like scaffold and functionalization by offering bioactive stimuli are also summarized in the review, and the barriers developing engineering technologies need to overcome to be popularized are discussed.
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Osteoartrite , Disco da Articulação Temporomandibular , Humanos , Disco da Articulação Temporomandibular/cirurgia , Engenharia TecidualRESUMO
BACKGROUND: Patients with schizophrenia (SCZ) exhibit sex differences in various aspects, and patients with SCZ have a high prevalence of internet addiction (IA). However, sex differences in IA among patients with SCZ mostly remain unstudied, particularly in Chinese adolescent patients with SCZ. This study investigated sex differences in prevalence, risk factors, and clinical correlates of IA among Chinese adolescent patients with SCZ. METHODS: A total of 706 adolescent patients with SCZ were enrolled in this study using a cross-sectional design and a convenience sampling method. Demographics and clinical data of the patients were collected using a standardized clinical assessment form. The Positive and Negative Syndrome Scale (PANSS) and the Young's Internet Addiction Test were used to evaluate psychopathological symptoms and IA respectively. RESULTS: Overall, the prevalence of IA among Chinese adolescent patients with SCZ was 26.30% (95% CI: 23.09-29.60%). In Chinese adolescents with SCZ, there was a sex difference in the comorbidity of IA (males: 33.33% vs. females: 21.69%). Binary logistic regression analysis showed that IA was significantly predicted by good socioeconomic status in male and female patients with SCZ. City of living and PANSS total score were associated with IA in male patients with SCZ. In contrast, hospitalization rate and depression score were associated with IA in female patients with SCZ. CONCLUSION: Our study suggests sex differences in clinical correlates of IA in Chinese adolescent patients with SCZ. An additional longitudinal study is required to confirm the findings of the present study.
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Comportamento Aditivo , Esquizofrenia , Humanos , Masculino , Feminino , Adolescente , Caracteres Sexuais , Prevalência , Estudos Transversais , Transtorno de Adição à Internet , Esquizofrenia/epidemiologia , Comportamento Aditivo/diagnóstico , Comportamento Aditivo/epidemiologia , China/epidemiologia , InternetRESUMO
The attainment of a substantial aperture in the rotating synthetic aperture imaging system involves the rotation of a slender rectangular primary mirror. This constitutes a pivotal avenue of exploration in space telescope research. Due to the considerable aspect ratio of the primary mirror, environmental disturbances can significantly impact its surface shape. Active optical technology can rectify surface shape irregularities through the detection of wavefront information. The Phase Diversity (PD) method utilizes images captured by the imaging system to compute wavefront information. In this study, the PD method is applied to rotating synthetic and other rectangular aperture imaging systems, employing Legendre polynomials to model the wavefront. The study delved into the ramifications stemming from the aperture aspect ratio and aberration size.
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Segmented plane mirrors constitute a crucial component in the self-aligned detection process for large-aperture space optical imaging systems. Surface shape errors inherent in segmented plane mirrors primarily manifest as tilt errors and piston errors between sub-mirrors. While the detection and adjustment techniques for tilt errors are well-established, addressing piston errors poses a more formidable challenge. This study introduces a novel approach to achieve long-range, high-precision, and efficient co-phase detection of segmented plane mirrors by proposing a segmented plane mirror shape detection method based on grazing incidence interferometry. This method serves to broaden the detection range of piston errors, mitigate the issue of the 2π ambiguity resulting from piston errors in co-phase detection, and extend the detection capabilities of the interferometer. By manipulating the incident angle of the interferometer, both rough and precise adjustments of the segmented plane mirrors can be effectively executed.
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We have developed tailor-designed mesoporous silica nanoparticles (MSNPs) specifically for delivering mRNA. Our unique assembly protocol involves premixing mRNA with a cationic polymer and then electrostatically binding it to the MSNP surface. Since the key physicochemical parameters of MSNPs could influence the biological outcome, we also investigated the roles of size, porosity, surface topology, and aspect ratio on the mRNA delivery. These efforts allow us to identify the best-performing carrier, which was able to achieve efficient cellular uptake and intracellular escape while delivering a luciferase mRNA in mice. The optimized carrier remained stable and active for at least 7 days after being stored at 4 °C and was able to enable tissue-specific mRNA expression, particularly in the pancreas and mesentery after intraperitoneal injection. The optimized carrier was further manufactured in a larger batch size and found to be equally efficient in delivering mRNA in mice and rats, without any obvious toxicity.
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Nanopartículas , Dióxido de Silício , Animais , Camundongos , Ratos , PorosidadeRESUMO
BACKGROUND: The rapid and accurate detection of moisture content is important to ensure maize quality. However, existing technologies for rapidly detecting moisture content often suffer from the use of costly equipment, stringent environmental requirements, or limited accuracy. This study proposes a simple and effective method for detecting the moisture content of single maize kernels based on viscoelastic properties. RESULTS: Two types of viscoelastic experiments were conducted involving three different parameters: relaxation tests (initial loads: 60, 80, 100 N) and frequency-sweep tests (frequencies: 0.6, 0.8, 1 Hz). These experiments generated corresponding force-time graphs and viscoelastic parameters were extracted based on the four-element Maxwell model. Then, viscoelastic parameters and data of force-time graphs were employed as input variables to explore the relationships with moisture content separately. The impact of different preprocessing methods and feature time variables on model accuracy was explored based on force-time graphs. The results indicate that models utilizing the force-time data were more accurate than those utilizing viscoelastic parameters. The best model was established by partial least squares regression based on S-G smoothing data from relaxation tests conducted with initial force of 100 N. The correlation coefficient and the root mean square error of the calibration set were 0.954 and 0.021, respectively. The corresponding values of the prediction set were 0.905 and 0.029, respectively. CONCLUSIONS: This study confirms the potential for accurate and fast detection of moisture content in single maize kernels using viscoelastic properties, which provides a novel approach for the detection of various components in cereals. © 2024 Society of Chemical Industry.
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Elasticidade , Sementes , Água , Zea mays , Zea mays/química , Viscosidade , Água/análise , Sementes/químicaRESUMO
Wheat (Triticum aestivum L.) radiation use efficiency (RUE) must be raised through crop breeding to further increase the yield potential, as the harvest index is now close to its theoretical limit. Field experiments including 209 wheat cultivars which have been widely cultivated in China since the 1940s were conducted in two growing seasons (2018-2019 and 2019-2020) to evaluate the variations of phenological, physiological, plant architectural, and yield-related traits and their contributions to RUE and to identify limiting factors for wheat yield potential. The average annual genetic gain in grain yield was 0.60% (or 45.32 kg ha-1 year-1 ; R2 = 0.44, P < 0.01), mainly attributed to the gain in RUE (r = 0.85, P < 0.01). The net photosynthetic rates were positively and closely correlated with grain RUE and grain yield, suggesting source as a limiting factor to future yield gains. Thirty-four cultivars were identified, exhibiting not only high RUE, but also traits contributing to high RUE and 11 other critical traits - of known genetic basis - as potential parents for breeding to improve yield and RUE. Our findings reveal wheat traits and the associated loci conferring RUE, which are valuable for facilitating marker-assisted breeding to improve wheat RUE and yield potential.
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Melhoramento Vegetal , Triticum , Triticum/genética , Fenótipo , Grão Comestível/genética , Fotossíntese/genéticaRESUMO
BACKGROUND: Predicting relationships between plant functional traits and environmental effects in their habitats is a central issue in terms of classic ecological theories. Yet, only weak correlation with functional trait composition of local plant communities may occur, implying that some essential information might be ignored. In this study, to address this uncertainty, the objective of the study is to test whether and how the consistency of trait relationships occurs by analyzing broad variation in eight traits related to leaf morphological structure, nutrition status and physiological activity, within a large number of plant species in two distinctive but comparable harsh habitats (high-cold alpine fir forest vs. north-cold boreal coniferous forest). RESULTS: The contrasting and/or consistent relationships between leaf functional traits in the two distinctive climate regions were observed. Higher specific leaf area, photosynthetic rate, and photosynthetic nitrogen use efficiency (PNUE) with lower N concentration occurred in north-cold boreal forest rather than in high-cold alpine forest, indicating the acquisitive vs. conservative resource utilizing strategies in both habitats. The principal component analysis illuminated the divergent distributions of herb and xylophyta groups at both sites. Herbs tend to have a resource acquisition strategy, particularly in boreal forest. The structural equation modeling revealed that leaf density had an indirect effect on PNUE, primarily mediated by leaf structure and photosynthesis. Most of the traits were strongly correlated with each other, highlighting the coordination and/or trade-offs. CONCLUSIONS: We can conclude that the variations in leaf functional traits in north-cold boreal forest were largely distributed in the resource-acquisitive strategy spectrum, a quick investment-return behavior; while those in the high-cold alpine forest tended to be mainly placed at the resource-conservative strategy end. The habitat specificity for the relationships between key functional traits could be a critical determinant of local plant communities. Therefore, elucidating plant economic spectrum derived from variation in major functional traits can provide a fundamental insight into how plants cope with ecological adaptation and evolutionary strategies under environmental changes, particularly in these specific habitats.
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Florestas , Plantas , Ecossistema , Fotossíntese/fisiologia , Clima , Folhas de Planta/fisiologiaRESUMO
Genetic markers can be linked with eco-physiological crop models to accurately predict genotype performance and individual markers' contributions in target environments, exploring interactions between genotype and environment. Here, wheat (Triticum aestivum L.) yield was dissected into seven traits corresponding to cultivar genetic coefficients in an eco-physiological model. Loci for these traits were discovered through the genome-wide association studies (GWAS). The cultivar genetic coefficients were derived from the loci using multiple linear regression or random forest, building a marker-based eco-physiological model. It is then applied to simulate wheat yields and design virtual ideotypes. The results indicated that the loci identified through GWAS explained 46%-75% variations in cultivar genetic coefficients. Using the marker-based model, the normalized root mean square error (nRMSE) between the simulated yield and observed yield was 13.95% by multiple linear regression and 13.62% by random forest. The nRMSE between the simulated and observed maturity dates was 1.24% by multiple linear regression and 1.11% by random forest, respectively. Structural equation modelling indicated that variations in grain yield could be well explained by cultivar genetic coefficients and phenological data. In addition, 24 pleiotropic loci in this study were detected on 15 chromosomes. More significant loci were detected by the model-based dissection method than considering yield per se. Ideotypes were identified by higher yield and more favourable alleles of cultivar genetic traits. This study proposes a genotype-to-phenotype approach and demonstrates novel ideas and tools to support the effective breeding of new cultivars with high yield through pyramiding favourable alleles and designing crop ideotypes.
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Estudo de Associação Genômica Ampla , Triticum , Marcadores Genéticos , Triticum/genética , Estudo de Associação Genômica Ampla/métodos , Desequilíbrio de Ligação , Alelos , Locos de Características Quantitativas/genética , Fenótipo , Genótipo , Polimorfismo de Nucleotídeo ÚnicoRESUMO
BACKGROUND AND AIMS: Physiological and morphological traits play essential roles in wheat (Triticum aestivum) growth and development. In particular, photosynthesis is a limitation to yield. Increasing photosynthesis in wheat has been identified as an important strategy to increase yield. However, the genotypic variations and the genomic regions governing morphological, architectural and photosynthesis traits remain unexplored. METHODS: Here, we conducted a large-scale investigation of the phenological, physiological, plant architectural and yield-related traits, involving 32 traits for 166 wheat lines during 2018-2020 in four environments, and performed a genome-wide association study with wheat 90K and 660K single nucleotide polymorphism (SNP) arrays. KEY RESULTS: These traits exhibited considerable genotypic variations in the wheat diversity panel. Higher yield was associated with higher net photosynthetic rate (r = 0.41, P < 0.01), thousand-grain weight (r = 0.36, P < 0.01) and truncated and lanceolate shape, but shorter plant height (r = -0.63, P < 0.01), flag leaf angle (r = -0.49, P < 0.01) and spike number per square metre (r = -0.22, P < 0.01). Genome-wide association mapping discovered 1236 significant stable loci detected in the four environments among the 32 traits using SNP markers. Trait values have a cumulative effect as the number of the favourable alleles increases, and significant progress has been made in determining phenotypic values and favourable alleles over the years. Eleven elite cultivars and 14 traits associated with grain yield per plot (GY) were identified as potential parental lines and as target traits to develop high-yielding cultivars. CONCLUSIONS: This study provides new insights into the phenotypic and genetic elucidation of physiological and morphological traits in wheat and their associations with GY, paving the way for discovering their underlying gene control and for developing enhanced ideotypes in wheat breeding.
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Estudo de Associação Genômica Ampla , Locos de Características Quantitativas , Locos de Características Quantitativas/genética , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único/genética , Triticum/genética , Fenótipo , Grão Comestível/genéticaRESUMO
BACKGROUND: Robotic-assisted Kasai portoenterostomy (RAKPE) has been utilized to treat biliary atresia (BA). However, RAKPE is not widely performed and its efficacy remains unknown. We summarized the experience of RAKPE for BA and determined its efficacy. MATERIALS AND METHODS: We retrospectively analyzed 25 consecutive infants with non-syndromic type III BA who received RAKPE in our center from January 2020 to July 2021. RAKPE is a three-arm setup and four-trocar operation. Bipolar coagulation was used to dissect the small blood vessels at the hepatic portal. The fibrous cone was shallowly transected with bending electric scissors, followed by gelatin sponge compression to staunch the hemorrhage. Finally, a wide anastomosis was accurately constructed. Demographics and outcomes were recorded. RESULTS: The mean operative time was 211.64 ± 18.93 min. No conversion to laparotomy or intraoperative complications occurred. The mean estimated blood loss was 7.64 ± 2.43 mL. Enteral feeding was resumed after 3.44 ± 1.23 days. All patients achieved bile excretion postoperatively, and dark green bile-stained stools were passed 1.50 days (range 1.00-3.00 days) after surgery. The average postoperative length of hospital stay was 10.32 ± 2.59 days. The jaundice clearance (JC) rate was 76.00% within 6 months after surgery and the incidence of cholangitis was 48.00% within 1 year following surgery. The survival with native liver (SNL) rate was 80.00% at 1 year and 66.67% at 2 years. CONCLUSION: RAKPE can be regarded as a treatment option for patients with BA due to the good outcomes reported. However, long-term studies comparing open or laparoscopic approaches are needed.
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Atresia Biliar , Laparoscopia , Procedimentos Cirúrgicos Robóticos , Lactente , Humanos , Atresia Biliar/cirurgia , Portoenterostomia Hepática , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/efeitos adversos , Laparoscopia/efeitos adversos , Resultado do TratamentoRESUMO
BACKGROUND: Robotic-assisted surgery (RAS) is being increasingly used in pediatric choledochal cysts (CCs), but is most commonly performed in older children and adolescents. The outcomes in young infants remain to be explored. The purpose of this study is to compare outcomes in infants aged ≤ 1 year with an older cohort. METHODS: From July 2015 to January 2020, a retrospective study was conducted to evaluate the RAS in patients with CCs at our institution. Patients were divided into two groups (group A ≤ 1 year old and group B > 1 year old). Demographics, intraoperative details, complications, and outcomes were analyzed. RESULTS: A total of 79 patients were included in the study (28 patients in group A and 51patients in group B). The median age of patients at the surgery in group A was 4.9 months (IQR: 3.1-9.1), compared with 46.8 months (IQR: 28.5-86.5) in group B. Three patients in group A were neonates. No conversion to open surgery was required. No significant differences were found between the two groups including sex, Todani type, or diameter of the cysts. The diameter of the common hepatic duct was smaller in group A (6.0 ± 1.7 vs. 9.0 ± 3.0 mm; p < 0.001). Group A had the longer hepaticojejunostomy time [51(44-58) vs. 42(38-53) min; p = 0.013], while Group B had the longer cyst excision time [43(41-59) vs. 50(43-60) min; p = 0.005]. However, their total operative time and console time were similar. There were no statistical differences in length of hospital stay and complications between the two groups. CONCLUSIONS: Robot-assisted cyst resection and hepaticojejunostomy are feasible and safe in infants ≤ 1 year old. Age cannot be considered an absolute contraindication for robotic surgery in patients with CCs.
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Cisto do Colédoco , Laparoscopia , Procedimentos Cirúrgicos Robóticos , Lactente , Recém-Nascido , Adolescente , Criança , Humanos , Cisto do Colédoco/cirurgia , Estudos Retrospectivos , Anastomose em-Y de Roux/efeitos adversos , Fígado/cirurgia , Resultado do TratamentoRESUMO
Allostery is an important regulatory mechanism of protein functions. Among allosteric proteins, certain protein structure types are more observed. However, how allosteric regulation depends on protein topology remains elusive. In this study, we extracted protein topology graphs at the fold level and found that known allosteric proteins mainly contain multiple domains or subunits and allosteric sites reside more often between two or more domains of the same fold type. Only a small fraction of fold-fold combinations are observed in allosteric proteins, and homo-fold-fold combinations dominate. These analyses imply that the locations of allosteric sites including cryptic ones depend on protein topology. We further developed TopoAlloSite, a novel method that uses the kernel support vector machine to predict the location of allosteric sites on the overall protein topology based on the subgraph-matching kernel. TopoAlloSite successfully predicted known cryptic allosteric sites in several allosteric proteins like phosphopantothenoylcysteine synthetase, spermidine synthase, and sirtuin 6, demonstrating its power in identifying cryptic allosteric sites without performing long molecular dynamics simulations or large-scale experimental screening. Our study demonstrates that protein topology largely determines how its function can be allosterically regulated, which can be used to find new druggable targets and locate potential binding sites for rational allosteric drug design.
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Simulação de Dinâmica Molecular , Proteínas , Regulação Alostérica , Proteínas/química , Sítio Alostérico , Sítios de Ligação , Ligação ProteicaRESUMO
Strontium (Sr) is a trace element in the human body that can promote bone formation and inhibit bone absorption. A conversion coating of strontium phosphate (Sr-P) on the surface of titanium (Ti) can improve its biological properties and has many potential applications in the fields of dentistry and orthopedics. In the present study, Sr-P coatings with SrHPO4 and Sr3(PO4)2 crystals on Ti are prepared by a phosphate chemical conversion (PCC) treatment and the effect of pH values on the properties of the Sr-P coatings is researched. The results prove that the phase composition, morphology, and corrosion resistance of the coated Ti vary according to the pH values of the PCC solution. The morphology of the conversion deposition on Ti changes from plat-like to cluster-like and then to homogeneous microcrystals as the pH value changes from 2.50 to 3.25. Only discrete SrHPO4 crystals are generated on the substrate at lower pH values, while relatively stable Sr3(PO4)2 and SrHPO4 crystals grow and subsequently form an integrated coating on the Ti as the pH exceeds 2.50. The cross-sectional morphologies and bonding strength of different coatings are also researched. The corrosion resistance of coated Ti improves compared with that of bare Ti because of the Sr-P coatings with a Sr3(PO4)2 phase. In addition, it is indicated that the Sr-P coatings on Ti can improve the adhesion and differentiation of BMSCs.
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Magnesium phosphate (MgP) has garnered growing interest in hard tissue replacement processes due to having similar biological characteristics to calcium phosphate (CaP). In this study, an MgP coating with the newberyite (MgHPO4·3H2O) was prepared on the surface of pure titanium (Ti) using the phosphate chemical conversion (PCC) method. The influence of reaction temperature on the phase composition, microstructure, and properties of coatings was systematically researched with the use of an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a laser scanning confocal microscope (LSCM), a contact angle goniometer, and a tensile testing machine. The formation mechanism of MgP coating on Ti was also explored. In addition, the corrosion resistance of the coatings on Ti was researched by assessing the electrochemical behavior in 0.9% NaCl solution using an electrochemical workstation. The results showed that temperature did not obviously affect the phase composition of the MgP coatings, but affected the growth and nucleation of newberyite crystals. In addition, an increase in reaction temperature had a great impact on properties including surface roughness, thickness, bonding strength, and corrosion resistance. Higher reaction temperatures resulted in more continuous MgP, larger grain size, higher density, and better corrosion resistance.