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Mild alkali treatment can potentially be developed as a greener alternative to the traditional alkali treatment of starch, but the effect of mild alkali on starch is still understudied. Normal and waxy rice starches were subjected to mild alkali combined with hydrothermal treatment to investigate their changes in physicochemical properties. After mild alkali treatment, the protein content of normal and waxy rice starches decreased from 0.76% to 0.23% and from 0.89% to 0.23%, respectively. Mild alkali treatment decreased gelatinization temperature but increased the swelling power and solubility of both starches. Mild alkali treatment also increased the gelatinization enthalpy of waxy rice starch from 20.01 J/g to 25.04 J/g. Mild alkali treatment at room temperature increased the pasting viscosities of both normal and waxy rice starches, whereas at high temperature, it decreased pasting viscosities during hydrothermal treatment. Alkali treatment significantly changed the properties of normal and waxy rice starch by the ionization of hydroxyl groups and the removal of starch granule-associated proteins. Hydrothermal conditions promoted the effect of alkali. The combination of hydrothermal and alkali treatment led to greater changes in starch properties.
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Antibacterial resistance in wild animals has been increasingly reported worldwide, even though they are usually not directly exposed to clinically relevant antibiotics. Crested ibis, one of the rarest birds in the world, usually forages in paddy fields and prefer to nest and breed near villages that is greatly influenced by anthropogenic activities. We sampled the feces of crested ibises, as well as their habitat environment samples, to explore the pollution characteristics of heavy metals, antibiotics and antibiotic resistance genes (ARGs). Results showed that the pollution characteristics of heavy metals, antibiotic, ARGs and gut microbiota of crested ibis were more related by host lifestyle and habitats. Captive ibises had higher relative abundances of the total ARGs and tetracycline concentrations compared with feralization and wild ibises, while the heavy metal contents had shown the opposite result. The Characteristics of pollutants in the corresponding environmental samples also exhibited high similarity with the results of fecal samples. The relative abundances of Proteobacteria and Actinobacteria were significantly different between captive and wild individuals, while the abundance of majority bacterial genera was generally higher in wild populations. The concentrations of heavy metals in soil (Cd, Cu and Zn) and water (Cd, Cu, Zn and Cr) were both exceeded the background soil levels or surface water quality standards, suggesting multi-element contamination in the habitat. Ecological risk assessments of soils by Igeo and Er showed that the habitats of wild ibises were heavily and moderately contaminated by Cd, which would possibly pose a threat to the health of ibises. PLS-PM analysis indicated that microbial compositions and residual antibiotics had the most substantial impact on the dynamic changes in ARGs of ibis. Overall, this work provides a comprehensive understanding of the characteristics, risks of those contaminations, and their effects on the ARGs in the habitat of crested ibis.
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Sarcomatoid renal cell carcinoma typically signifies an exceptionally poor prognosis, with patients rarely surviving beyond one year. An 83-year-old male presented to our hospital with complaints of headache and left-sided limb weakness. Computed tomography (CT) scans of the head and lungs disclosed a mass within the right temporal lobe, accompanied by peritumoral edema in the right cerebral hemisphere. Brain magnetic resonance imaging (MRI) with contrast enhancement and diffusion-weighted imaging (DWI) delineated a mass in the right temporal lobe, measuring 3 × 3 × 3 cm. He underwent cytoreductive surgery successively in the neurosurgery and urology departments. Despite experiencing postoperative tumour recurrence, the patient has lived close to four years to date. This case report illustrates that cytoreductive surgery combined with systemic pharmacotherapy can still confer significant survival benefits for elderly patients.
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Neoplasias Encefálicas , Carcinoma de Células Renais , Neoplasias Renais , Humanos , Masculino , Carcinoma de Células Renais/secundário , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/diagnóstico por imagem , Neoplasias Renais/patologia , Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/diagnóstico por imagem , Idoso de 80 Anos ou mais , Procedimentos Cirúrgicos de Citorredução/métodos , Tomografia Computadorizada por Raios X , Imageamento por Ressonância Magnética , Lobo Temporal/patologia , Lobo Temporal/diagnóstico por imagemRESUMO
Rice was collected over the entire grain filling period (about 40 days) to explore the multi-structure evolution and gelatinization behavior changes of starch. During the early stage (DAA 6-14), the significant reduction in lamellar repeat distance (10.04 to 9.68 nm) and relative crystallinity (26.6 % to 22.7 %) was due to initial rapid accumulation of amylose (from 9.38 % to 14.05 %) and short amylopectin chains. Meanwhile, the decreased proportion of aggregation structure resulted in a decrease in the gelatinization temperature and a narrowed range of gelatinization temperature also indicated an increase in homogeneity as starch matured. Gelatinization enthalpy was mainly controlled by aggregation structure, which was negatively and positively related to the amylose content and the degree of order respectively. Peak viscosity of starch pasting increased and reached a maximum (924 cP) at DAA-21 due to larger granule size. Amylose and short amylopectin chains with degree of polymerization 6-12 showed positive and negative correlation with short-term retrogradation ability (setback value) respectively. The dynamics of different scale structure during grain filling had varying degrees of impact on gelatinization properties.
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Amilopectina , Amilose , Oryza , Amido , Oryza/química , Amilose/química , Amido/química , Amilopectina/química , Viscosidade , Temperatura , Gelatina/química , Grão Comestível/químicaRESUMO
Two complementary regiodivergent C-H alkynylations of 2-arylthiazoles are reported. When RuII catalysis is employed, an aryl ortho-alkynylation process is favored. The alkynylated products are gained in good yields. With the use of PdII catalysis, a thiazole C5-alkynylation process is developed, allowing for the construction of C5-alkynylated products. This strategy not only expands the methods for the functionalization of 2-arylthiazoles, but also provides new opportunities for the rapid assembly of complex molecular structures, which may have great potential in organic synthesis, medicinal chemistry, and materials science.
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Normal and waxy maize starches were treated with mild alkali treatment (pH 8.5, 9.9, 11.3) in two temperature-time combinations (25 °C for 1 h and 50 °C for 18 h) to investigate the effect on starch structure and properties. Mild alkali treatment partly removed the starch granule-associated proteins and lipids of normal (from 0.31 % to 0.24 % and from 0.77 % to 0.55 %, respectively) and waxy maize starches (from 0.22 % to 0.18 % and from 0.24 % to 0.15 %, respectively). Gelatinization enthalpy of waxy maize starch increased with alkali treatment from 16.20 J·g-1 to 21.95 J·g-1, indicating that amylopectin (AP) rearrangement and AP-AP double helices formation might occur. But amylose could inhibit these effects by restricting mobility of amylopectin, and no such changes occurred for normal maize starch. Alkali treatment decreased gelatinization temperature and increased peak and final viscosity. Alkali treatment decreased trough viscosity and increased setback of normal maize starch. The hydrothermal treatment promoted the effect of alkali, attributed to the more rapid molecular motion at higher temperature. Normal and waxy starches showed different changes after alkali treatment, indicating that amylose played an important role in controlling the effect of alkali and hydrothermal treatment, primarily as an obstructer of amylopectin rearrangement in mild alkali treatment.
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Álcalis , Amilopectina , Amilose , Amido , Zea mays , Zea mays/química , Amido/química , Álcalis/química , Viscosidade , Amilopectina/química , Amilose/química , Temperatura , Concentração de Íons de HidrogênioRESUMO
BACKGROUND: A three-dimensional (3D) reconstruction of the kidney, parapelvic cyst and the collecting system was conducted using the 3D Slicer software. The reconstructed image was used to form a virtual endoscope to assist flexible ureteroscopic incision and drainage was performed with a holmium laser for treating parapelvic cysts. The effectiveness of this assistive technique was assessed. METHODS: This was a retrospective cohort study. The clinical information of 59 patients undergoing flexible ureteroscopic incision and drainage for parapelvic cysts in two medical centers was collected. 3D Slicer software reconstruction and virtual endoscopic imaging were performed for 28 cases. Before the operation, the best point for incision on the collecting system's mucosa was assessed by virtual endoscope imaging. Propensity score matching was adopted for the reconstructive and non-reconstructive groups. RESULTS: After matching, the reconstructive group and non-reconstructive group both had 21 cases each. The operation time in the reconstructive and non-reconstructive groups was 38.81±5.01 and 51.00±18 minutes, respectively. Statistically significant differences existed between the two groups (t=7.024, P<0.001). No statistical significance was found in postoperative fever, immediate postoperative C reactive protein (CRP), length of postoperative hospital stay and cyst diameter three months after the operation. CONCLUSIONS: The operator was provided with a more direct and real vision when 3D Slicer software reconstruction was adopted via virtual endoscopic imaging to assist flexible ureteroscopic parapelvic cyst incision. This helped reduce the operation time. Further follow-ups and observations are required to assess the long-term efficacy of flexible ureteroscopic parapelvic cyst incision.
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Ureteroscopia , Humanos , Estudos Retrospectivos , Ureteroscopia/métodos , Feminino , Masculino , Pessoa de Meia-Idade , Estudos de Coortes , Imageamento Tridimensional/métodos , Adulto , Idoso , Doenças Renais Císticas/cirurgia , Doenças Renais Císticas/diagnóstico por imagem , Drenagem/métodos , Lasers de Estado Sólido/uso terapêutico , Pelve Renal/cirurgia , Pelve Renal/diagnóstico por imagemRESUMO
Near-infrared (NIR) responsive nanoparticles are an important platform for multimodal phototherapy. Importantly, the simultaneous NIR-triggered photodynamic (PDT) and photothermal (PTT) therapy is a powerful approach to increase the antitumor efficiency of phototherapic nanoparticles due to the synergistic effect. Herein, a boron dipyrromethene (BODIPY)-based amphiphilic dye with enhanced electron donor-acceptor-donor (D-A-D) structure (BDP-AP) was designed and synthesized, which could self-assemble into stable nanoparticles (BDP-AP NPs) for the synergistic NIR-triggered PDT/PTT therapy. BDP-AP NPs synchronously generated singlet oxygen (1O2) and achieved preeminent photothermal conversion efficiency (61.42%). The in vitro and in vivo experiments showed that BDP-AP NPs possessed negligible dark cytotoxicity and infusive anticancer performance. BDP-AP NPs provide valuable guidance for the construction of PDT/PTT-synergistic NIR nanoagents to improve the efficiency of photoinduced cancer therapy in the future.
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Antineoplásicos , Compostos de Boro , Ensaios de Seleção de Medicamentos Antitumorais , Raios Infravermelhos , Fotoquimioterapia , Fármacos Fotossensibilizantes , Terapia Fototérmica , Compostos de Boro/química , Compostos de Boro/farmacologia , Compostos de Boro/síntese química , Humanos , Animais , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/síntese química , Camundongos , Estrutura Molecular , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Nanopartículas/química , Sobrevivência Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Relação Estrutura-Atividade , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/síntese química , Relação Dose-Resposta a Droga , Neoplasias Experimentais/patologia , Neoplasias Experimentais/tratamento farmacológico , Camundongos Endogâmicos BALB CRESUMO
Granule-associated surface lipids (GASLs) and internal lipids showed different lipid-amylose relationships, contents, and distributions, suggesting their differing biological origins and functions, among waxy, normal, and high-amylose rice starch. The GASL content mainly depended on the pore size, while internal lipids regulated starch biosynthesis, as indicated by correlations of internal lipids with the chain length distribution of amylopectin and amylose content. Of the 1346 lipids detected, 628, 562, and 408 differentially expressed lipids were observed between normal-waxy, high-amylose-waxy, and normal-high-amylose starch, respectively. After the removal of GASLs, the higher lysophospholipid content induced greater decreases in the peak and breakdown viscosity and swelling power, while the highest digestibility increase was found with the highest triacylglycerol content. Thus, different GASL compositions led to different digestibility, swelling, and pasting outcomes. This study sheds new light on the mechanism of the role of GASLs in the structure and properties of starch, as well as in potential modifications and amyloplast membrane development.
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Amilose , Digestão , Lipidômica , Lipídeos , Oryza , Amido , Oryza/química , Oryza/metabolismo , Amilose/metabolismo , Amilose/análise , Amilose/química , Lipídeos/química , Amido/química , Amido/metabolismo , ViscosidadeRESUMO
Studying diversity in local barley varieties can help advance novel uses for the grain. Therefore, starch was isolated from nine Ethiopian food barley varieties to determine starch structural, pasting, thermal, and digestibility characteristics, as well as their inter-relationships. The amylose content in the varieties significantly varied from 24.5 to 30.3%, with a coefficient of variation of 6.1%. The chain length distributions also varied significantly, and fa, fb1, fb2, and fb3 ranged from 26.3 to 29.0, 48.0 to 49.7, 15.0 to 15.9, and 7.5 to 9.5%, respectively. Significant variations were also exhibited in absorbance peak ratios, as well as thermal, pasting, and in vitro digestibility properties, with the latter two parameters showing the greatest diversity. Higher contents of amylose and long amylopectin fractions contributed to higher gelatinization temperatures and viscosities and lower digestibility. Structural characteristics showed strong relationships with viscosity, thermal, and in vitro digestibility properties. Cross 41/98 and Dimtu varieties are more suitable in functional food formulations and for bakery products. These results might inspire further studies to suggest target-based starch modifications and new product development.
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Normal and waxy maize starches with and without removal of starch granule surface lipids (SGSLs) were crosslinked by POCl3 (0.01 %, 0.1 % and 1 %). Crosslinked starches showed lower swelling power and solubility, but higher pasting viscosity, pseudoplasticity, thixotropy, storage modulus and loss modulus. Crosslinking increased the double helical structure but decreased the crystallinity for waxy maize starch. The phosphorus content of crosslinked waxy maize starches after SGSLs removal increased, indicating SGSLs removal promoted crosslinking. SGSLs removal increased G' and G" for crosslinked waxy maize starches. SGSLs removal increased SP and solubility and decreased pasting and rheological parameters of starches. With increased POCl3 dosage, the effect of SGSLs removal on starch properties was gradually suppressed by crosslinking. Waxy and normal maize starches showed significantly different changes with crosslinking and SGSLs removal, and the presence of amylose seemed to impede the effect of crosslinking and SGSLs removal. The removal of SGSLs could extend the application of crosslinked starch in frozen foods, drinks, and canned foods as thickener and stabilizer, due to its better hydrophilicity and viscous liquid-like rheological properties. The study will assist carbohydrate chemists and food processors in developing new food products.
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Amido , Zea mays , Zea mays/química , Amido/química , Amilose/química , Amilopectina/química , Viscosidade , Ceras/químicaRESUMO
Roles of temperature, moisture and starch granule-associated surface lipids (SGASL) during heat-moisture treatment (HMT) of waxy highland barley starch were elucidated. Starch without SGASL showed a higher increase in ratio (1016/993 cm-1) (0.095-0.121), lamellar peak area (88), radius of gyration (Rg1, 0.9-1.8 nm) and power-law exponents (0.19-0.42) than native starch (0.038-0.047, 46, 0.1-0.6 nm, 0.04-0.14), upon the same increase in moisture or temperature. Thus, removing SGASL promoted HMT. However, after HMT (30 % moisture, 120 °C), native starch showed lower relative crystallinity (RC, 11.67 %) and lamellar peak area (165.0), longer lamellar long period (L, 14.99 nm), and higher increase in peak gelatinization temperature (9.2-13.3 °C) than starch without SGASL (12.04 %, 399.2, 14.52 nm, 4.7-6.1 °C). This suggested that the resulting SGASL-amylopectin interaction further destroyed starch structure. Starch with and without SGASL showed similar trends in RC, lamellar peak area, L and Rg1 with increasing temperature, but different trends with increasing moisture, suggesting that removing SGASL led to more responsiveness to the effects of increasing moisture. Removing SGASL resulted in similar trends (RC and lamellar peak area) with increasing moisture and temperature, suggesting that the presence of SGASL induced different effects on moisture and temperature.
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Amilopectina , Hordeum , Temperatura , Temperatura Alta , Amido/química , LipídeosRESUMO
Characterization of local varietal barley quality diversity can help boost further development of novel value-added utilization of the grain. Therefore, in this study starch was isolated from 11 Ethiopian malting barley varieties to determine starch structural, pasting, thermal and digestibility characteristics, and their inter-relationships. The varieties showed significant differences in all amylopectin chain length fractions, and the A, B1, B2 and B3 chains ranged from 25.4 to 30.1, 47.4-50.1, 14.3-16.0 and 7.8-9.0 %, respectively. The varieties also exhibited significant variation in amylose content, relative crystallinity, absorbance peak ratios, pasting and thermal properties. Moreover, on average about 83 % raw starch of the varieties was classified as slowly digestible and resistant, whereas after gelatinization this was reduced to 9 %. Molecular and crystalline structures were strongly related to pasting properties, thermal characteristics and in vitro digestibility of the starches. The study provides information on some starch quality characteristics and the inter-relationships among the parameters, and might inspire further studies to suggest possible target-based starch modifications, and future novel utilization of barley. More studies are required to investigate the association of starch quality parameters with malting quality attributes.
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Hordeum , Amido , Amido/química , Estrutura Molecular , Amilopectina/química , Amilose/química , ViscosidadeRESUMO
A gentle and effective method for the photocatalytic dual functionalization of allenes with high regio- and stereoselectivity using a nonmetallic catalyst is described. Inexpensive and easily available sulfinates and TMSN3 were employed as sulfone and azido sources, respectively. The method is characterized by satisfactory substrate compatibility and tolerance toward functional groups. The straightforward initial mechanistic experiments suggested that the reaction could follow a radical pathway. The synthesis of vinylsulfone azide derivatives presented here offers a promising scaffold for the future development of vinyl sulfone-based drugs and functional bioorthogonal reagents.
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Background: Erectile dysfunction (ED) is a complex disorder of biopsychosocial etiology. Approximately 3%-77 % of adult men worldwide are more or less affected by ED. Objective: This cross-sectional study investigated the association between ED and socioeconomic status (SES) based on a nationally representative adult male population. Methods: The poverty income ratio (PIR), which refers to household income ratio to the established poverty line, was used to assess SES. Oxidative stress related to diet and lifestyle was reflected by oxidative balance score (OBS). Erectile function was evaluated using a questionnaire. Based on the results of the questionnaire, participants were divided into two groups of those without ED (always or almost always be able to erect and keep erection, usually be able to erect and keep erection) and with ED (sometimes be able to erect and keep erection, never be able to erect and keep erection). Multivariate logistic regression, multiple models, and restricted cubic spline (RCS) were used to analyze and describe the interaction between ED, OBS, and SES. Results: Compared with men without ED, those with ED were more likely to be older in age (43.98 vs 37.74, Pï¼0.0001), and less educated (P < 0.001), and with a ratio of family income to poverty less than 3.5 (P = 0.02), higher BMI (30.11 vs 27.84, Pï¼0.0001), lower OBS (21.71 vs 23.17, P = 0.04), having habit of smoking (P = 0.04), with diabetes (Pï¼0.0001), and with hypertension (P = 0.003). Participants with higher PIR were more likely to report good erectile function than those with lower PIR through multivariate analysis (OR = 0.49, 95 % CI = 0.31-0.78, P = 0.005). The RCS model revealed a negative non-linear correlation of PIR with ED when PIR ≤3.89. It is interesting to note that PIR wasï¼3.89 showed a positive non-linear relationship with ED. Conclusion: The social determinants of health and intake of oxidants and antioxidants were considered as risk factors for ED and could be studied as a research focus in the future.
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Background: Gliomas are the most common primary tumors of the central nervous system, with high heterogeneity and highly variable survival rates. Accurate classification and prognostic assessment are key to the selection of treatment strategies. One hallmark of the tumor is resistance to cell death. PANoptosis, a novel mode of programmed cell death, has been frequently reported to be involved in the innate immunity associated with pathogen infection and played an important role in cancers. However, the intrinsic association of PANoptosis with glioma requires deeper investigation. Methods: The genetics and expression of the 17 reported PANoptosome-related genes were analyzed in glioma. Based on these genes, patients were divided into two subtypes by consensus clustering analysis. After obtaining the differentially expressed genes between clusters, a prognostic model called PANopotic score was constructed after univariate Cox regression, LASSO regression, and multivariate Cox regression. The expression of the 5 genes included in the PANopotic score was also examined by qPCR in our cohort. The prognostic differences, clinical features, TME infiltration status, and immune characteristics between PANoptotic clusters and score groups were compared, some of which even extended to pan-cancer levels. Results: Gene mutations, CNVs and altered gene expression of PANoptosome-related genes exist in gliomas. Two PANoptotic clusters were significantly different in prognosis, clinical features, immune characteristics, and mutation landscapes. The 5 genes included in the PANopotic score had significantly altered expression in glioma samples in our cohort. The high PANoptotic score group was inclined to show an unfavorable prognosis, lower tumor purity, worse molecular genetic signature, and distinct immune characteristics related to immunotherapy. The PANoptotic score was considered as an independent prognostic factor for glioma and showed superior prognostic assessment efficacy over several reported models. PANopotic score was included in the nomogram constructed for the potential clinical prognostic application. The associations of PANoptotic score with prognostic assessment and tumor immune characteristics were also reflected at the pan-cancer level. Conclusion: Molecular subtypes of glioma based on PANoptosome-related genes were proposed and PANoptotic score was constructed with different clinical characteristics of anti-tumor immunity. The potential intrinsic association between PANoptosis and glioma subtypes, prognosis, and immunotherapy was revealed.
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Background: Arf GTPase-activating proteins are aberrantly expressed in a variety of tumors, but their role in clear cell renal cell carcinoma (ccRCC) was unclear. Exploring the biological role of Arf GAP with GTP binding protein like domain, Ankyrin repeat and PH domain 2 (AGAP2) in ccRCC could improve our understanding on the aggressiveness and immune relevance of ccRCC. Methods: The expression of AGAP2 was analyzed based on the Cancer Genome Atlas (TCGA) database and verified in ccRCC samples using immunohistochemistry. The association between AGAP2 and clinical cancer stages was explored by TCGA dataset and UALCAN. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed to analyze the biological functions of AGAP2-related genes. Moreover, the relationship between AGAP2 and immune cell infiltration was investigated with TIME and TCGA dataset. Results: Compared to normal tissues, AGAP2 was upregulated in ccRCC tissues. Higher expression of AGAP2 was associated with clinical cancer stages, TNM stages, pathologic stages, and status. Prognostic analysis on AGAP2 showed that AGAP2 overexpression was associated with KIRC overall survival (OS) reduction (P = 0.019). However, higher expression of AGAP2 may improve the OS of CESC (P = 0.002), THYM (P = 0.006) and UCEC (P = 0.049). GO and KEGG analysis showed that AGAP2-related genes was related to T cell activation, immune activity and PD-L1 expression and PD-1 checkpoint pathway. Furthermore, our study showed that AGAP2 were significantly associated with T cells, Cytotoxic cells, Treg, Th1 cells, CD8 T cells, T helper cells. And AGAP2 expression level affected the abundance of immune cells infiltration. The infiltrating level of immune cells was different between the AGAP2 high-expression and low-expression groups. Conclusion: The expression of AGAP2 in ccRCC was higher than that in normal kidney tissues. It was significantly associated with clinical stage, poor prognosis, and immune cell infiltration. Therefore, AGAP2 may become an important component for ccRCC patients who receive precision cancer therapy and may be a promising prognostic biomarker.
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The effects of starch granule-associated surface lipids removal on hull-less barley starch structure formed by heat-moisture treatment were investigated. Removing surface lipids made the peak at 2θ of 13° disappear and resulted in higher lamellar peak intensity after harsh treatment and a lower reduction in mass fractal dimension (from 2.49 to 2.43) and radius of gyration (from 24.3 to 24.0) when temperature increased from 100 to 120 °C at 20 % moisture. Treatment at 25 % moisture and 120 °C decreased relative crystallinity (from 15.73 % to 7.43 %) and Gaussian peak area (from 646.7 to 137.7) of native starch, and decreased relative crystallinity (from 14.24 % to 12.56 %) and Gaussian peak area (from 604.1 to 539.6) for starch without surface lipids. Different trends of change in lamellar thickness, linear crystallinity, peak temperatures, and enthalpy of gelatinization were observed among modified starches with increasing temperature and/or moisture content. These results demonstrate that removing surface lipids changes structure of heat-moisture treated starch.
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Hordeum , Amido , Amido/química , Temperatura Alta , Temperatura , LipídeosRESUMO
Starch granule-associated surface and channel lipids (SGALs) were effectively removed from waxy maize starch (WMS) and normal maize starch (NMS), then the starches were crosslinked by different levels of sodium trimetaphosphate (STMP) (0.25 %, 0.5 %, 1 % and 2 %). The effective removal of SGALs and successful crosslinking, were evidenced by the disappearance of surface-fluorescence and channel-fluorescence of Pro-Q Diamond-stained granules, and the increased phosphorus content respectively. STMP crosslinking increased peak and final viscosity for WMS and NMS. Crosslinking at high STMP levels (0.5 %, 1 % and 2 %) transformed the starch pastes from thixotropic to anti-thixotropic. STMP crosslinking significantly decreased the tan δ values of maize starches, enhancing the elastic structure of the gel. Crosslinked maize starches without SGALs had lower breakdown than crosslinked starches at same STMP level, indicating higher tightened crosslinked starch granules after SGALs removal. Removal of SGALs increased the anti-thixotropy of crosslinked starches, facilitating the reorientation of crosslinked amylopectin/amylose molecules during shearing. Removal of SGALs increased the tan δ values from frequency sweep of WMS and NMS during STMP crosslinking, indicating the presence of surface-lipids and channel-lipids could enhance the elastic gel network structure of crosslinked maize starch.
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Amilopectina , Amilose , Amilopectina/química , Amilose/química , Diamante , Lipídeos , Fósforo , Polifosfatos , Amido/química , Zea mays/químicaRESUMO
Large A-type and small B-type starch granules separated from waxy and normal hull-less barley starches were investigated for their physicochemical properties. Hull-less barley starch granules were covered by a membrane composed mainly of phospholipids. Channels of waxy A- and B-type granules were rich in proteins and phospholipids. Compared with A-type starch, B-type starch exhibited higher specific surface area, volume and average diameter of mesopores. Waxy A-type granules exhibited the higher peak, breakdown, final and setback viscosity than did B-type granules, while normal A-type granules showed the lower peak, breakdown, final viscosity and the higher setback viscosity than did B-type granules. B-type starch gels with lower storage modulus exhibited a less elastic gel network structure and retrograded more slowly. Moreover, in vitro hydrolysis of starch showed that the B-type granules exhibited a higher hydrolysis extent and rate than the A-type granules in the first stage, which was consistent with higher initial α-amylase binding ability of B-type granules. The study showed that the A-type and B-type starch separated from waxy and normal hull-less barley exhibited very different physicochemical properties.