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This study used a self-administered questionnaire to investigate the relationship between HIV/AIDS knowledge, social discrimination, HIV self-efficacy, sexual behavioral characteristics and HIV testing behavior among young students with a history of sexual activity in Chongqing. Propensity score matching was used to construct a control group with similar demographic characteristics to the HIV testing group, only without HIV testing behaviors. Structural equation modeling was used to conduct chain-mediated effect analysis. The HIV testing rate among young students with a history of sexual behavior was 17.16%. Young students with HIV testing behavior had higher levels of HIV/AIDS knowledge, lower social discrimination, better self-efficacy, and no difference in sexual behavior characteristic scores between the two groups (P = 0.062). The mediated effect values of social discrimination and self-efficacy were 0.022 and 0.063, respectively, while their chain mediated effect value was 0.007. There was no mediated effect of sexual behavior characteristics. The level of young students' HIV/AIDS knowledge does not directly influence their HIV testing behavior but plays a complete chain mediating effect on HIV testing behavior through social discrimination and self-efficacy. HIV testing behavior should be promoted through the perspectives of enhancing HIV/AIDS knowledge level, reducing social discrimination, and improving self-efficacy.
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Síndrome de Inmunodeficiencia Adquirida , Infecciones por VIH , Humanos , Infecciones por VIH/diagnóstico , Autoeficacia , Análisis de Mediación , Conocimientos, Actitudes y Práctica en Salud , Conducta Sexual , Encuestas y Cuestionarios , Estudiantes , Prueba de VIH , Discriminación SocialRESUMEN
BACKGROUND: Brucellosis poses a significant public health concern. This study explores the spatial and temporal dynamic evolution of human brucellosis in China and analyses the spatial heterogeneity of the influencing factors related to the incidence of human brucellosis at the provincial level. METHODS: The Join-point model, centre of gravity migration model and spatial autocorrelation analysis were employed to evaluate potential changes in the spatial and temporal distribution of human brucellosis in mainland China from 2005 to 2021. Ordinary Least Squares (OLS), Geographically Weighted Regression (GWR), and Multi-scale Geographically Weighted Regression (MGWR) models were constructed to analyze the spatial and temporal correlation between the incidence rate of human brucellosis and meteorological and social factors. RESULTS: From 2005 to 2021, human brucellosis in China showed a consistent upward trend. The incidence rate rose more rapidly in South, Central, and Southwest China, leading to a shift in the center of gravity from the North to the Southwest, as illustrated in the migration trajectory diagram. Strong spatial aggregation was observed. The MGWR model outperformed others. Spatio-temporal plots indicated that lower mean annual temperatures and increased beef, mutton, and milk production significantly correlated with higher brucellosis incidence. Cities like Guangxi and Guangdong were more affected by low temperatures, while Xinjiang and Tibet were influenced more by beef and milk production. Inner Mongolia and Heilongjiang were more affected by mutton production. Importantly, an increase in regional GDP and health expenditure exerted a notable protective effect against human brucellosis incidence. CONCLUSIONS: Human brucellosis remains a pervasive challenge. Meteorological and social factors significantly influence its incidence in a spatiotemporally specific manner. Tailored prevention strategies should be region-specific, providing valuable insights for effective brucellosis control measures.
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Brucelosis , Animales , Bovinos , Humanos , China/epidemiología , Análisis Espacial , Brucelosis/epidemiología , Regresión Espacial , Ciudades , Incidencia , Análisis Espacio-TemporalRESUMEN
We aimed to obtain the optimal formula for human milk fat substitute (HMFS) through a combination of software and an evaluation model and further verify its practicability through an animal experiment. The results showed that a total of 33 fatty acid (FA) and 63 triglyceride (TAG) molecular species were detected in vegetable oils. Palmitic acid, oleic acid, linoleic acid, 18:1/16:0/18:1, 18:2/16:0/18:2, 18:1/18:1/18:1 and 18:1/18:2/18:1, were the main molecular species among the FAs and TAGs in the vegetable oils. Based on the HMFS evaluation model, the optimal mixed vegetable oil formula was blended with 21.3% palm oil, 2.8% linseed oil, 2.6% soybean oil, 29.9% rapeseed oil and 43.4% maize oil, with the highest score of 83.146. Moreover, there was no difference in the weight, blood routine indices or calcium and magnesium concentrations in the feces of the mice between the homemade mixed vegetable oil (HMVO) group and the commercial mixed vegetable oil (CMVO) group, while nervonic acid (C24:1) and octanoic acid (C8:0) were absorbed easily in the HMVO group. Therefore, these results demonstrate that the mixing of the different vegetable oils was feasible via a combination of computer software and an evaluation model and provided a new way to produce HMFS.
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Sustitutos de Grasa , Ácidos Grasos , Leche Humana , Aceites de Plantas , Programas Informáticos , Triglicéridos , Humanos , Animales , Aceites de Plantas/química , Ácidos Grasos/química , Leche Humana/química , Ratones , Triglicéridos/química , Sustitutos de Grasa/química , Aceite de Palma/química , Aceite de Soja/química , Aceite de Linaza/química , Aceite de Brassica napus/química , Aceite de Maíz/química , Caprilatos/química , Ácido Palmítico/química , Ácido Oléico/químicaRESUMEN
This study aimed to investigate the crystal network of bulk milk fat fractions and the partial coalescence, and the rheological properties of their oil-in-water (O/W) emulsions. Different milk fat fraction model systems were compared for their physicochemical properties, crystallization kinetics, and fat crystal networks across a range of temperatures. The extent of partial coalescence and rheological properties of the O/W emulsion prepared by different milk fat fractions were further analyzed. The results demonstrated that the ratio between saturated fatty acids (SFA) and unsaturated fatty acids and triacylglycerides (TAG) influenced the melting thermal behaviors, solid fat contents (SFC), and crystal networks of various milk fat fractions, which in turn influenced the partial coalescence and rheological characteristics of their O/W emulsions. Moreover, an excellent fit of the trend line confirmed that hardness increased exponentially with SFC. Trisaturated TAG in fractions with high melting points (HMF) such as milk fat fraction MF45, whose clarification temperature was 45°C, enriched long-chain SFA (saturated:unsaturated fatty acid = 2.2:1). We found that MF45 achieved higher SFC and hardness in the range of 0 to 40°C and, ultimately, formed a well-defined microstructural network with thick, rod-like crystals. Further, TAG in fractions with low melting points (LMF) such as MF10, whose clarification temperature was 10°C, were enriched with short-chain and unsaturated fatty acids (saturated:unsaturated fatty acid = 1.5:1), and a disordered crystal network in MF10, composed of randomly arranged, translucent platelets, was detected. Although fat globules of HMF and LMF were stabilized against coalescence, this could be attributed to a variety of mechanisms involving SFC, liquid fat, protective film around the fat globule, and minor lipids. According to the rheological profiles, all O/W emulsions exhibited weak viscoelastic "gel-like" structures [storage modulus (G') > loss modulus (G")] over most of the measured range. The G' values and apparent viscosity of HMF were greater than those of other fractions, indicating that the large and rigid crystals strengthen the networks more effectively.
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In this study, we aimed to detect the physicochemical properties of distilled products (residue and distillate) obtained from anhydrous milk fat (AMF) and its dry fractionation products (liquid and solid fractions at 25°C [25 L and 25 S]). The results showed that the saturated fatty acids and low- and medium molecular-weight triglycerides were easily accumulated in the distillate, and the percentage of unsaturated fatty acid and high molecular-weight triglycerides in the residue were higher, and these components in 25 S and 25 L were influenced more significantly than those in the AMF. In addition, the distillate had larger melting ranges in comparison with the distilled substrate, while the melting ranges of residue was smaller. The triglycerides were presented as the mixture crystal forms (α, ß', and ß crystal) in 25 S, AMF, and their distilling products, and it was transformed gradually to a single form as the increasing of distilling temperature. Moreover, the accumulated pattern of triglycerides was double chain length in 25 S, AMF, and their distilling products. These results provide a new approach to obtain the milk fat fractions with different properties, and the findings of this study enrich the theoretical basis of milk fat separation in practical production.
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Ácidos Grasos , Leche , Animales , Ácidos Grasos/análisis , Triglicéridos/análisis , Leche/química , Destilación , Fraccionamiento QuímicoRESUMEN
This study aimed to evaluate the effects of different concentration methods (nanofiltration and evaporation) and heat treatments on the gel properties of milk protein concentrate (MPC). The MPC gels were produced using glucono-δ-lactone (GDL) as an acidifier with different preheat treatments (30 min at 80°C and 5 min at 92°C). We then evaluated the effect of preheat treatments on MPC gel properties, including storage modulus (G'), loss tangent (tan δ), firmness, whey separation, and microstructure. The results indicated that without preheating, evaporation (EP)-MPC had higher G' and firmness, and lower tan δ and whey separation than nanofiltration (NF)-MPC. These results suggest that EP-MPC produced a better acid-induced gel than NF-MPC when no preheat treatments were performed. After preheating, however, except for a very small difference in the final G' (EP-MPC was higher), the 2 MPC did not differ significantly in firmness, final tan δ, or whey separation. Additionally, compared with the gel of unheated MPC, both preheat-treated gels (NF-MPC and EP-MPC) achieved increased G' and firmness and decreased tan δ and whey separation. The preheat-treated MPC also displayed a more flexible-stranded network. These findings demonstrate that, given a suitable heating treatment, NF-MPC compares favorably with EP-MPC in achieving desired gel properties.
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Filtración/métodos , Manipulación de Alimentos/métodos , Proteínas de la Leche/química , Leche/química , Animales , Bovinos , Gluconatos/química , Concentración de Iones de Hidrógeno , Lactonas/química , ReologíaRESUMEN
Aim: This paper determines the polymorphism distribution of the VDR BsmI gene in 350 patients and provides medication recommendations for osteoporosis based on detection results. Materials & methods: Chi-square tests compared genotype and allele frequencies with other populations. Results: Genotype frequencies were 91.66 bb, 8.72 Bb and 0.21% BB, with allelic frequencies of 95.43 b and 4.57% B, adhering to Hardy-Weinberg equilibrium. These findings suggest that VDR gene polymorphisms, particularly at the BsmIlocus, play an essential role in bone health and osteoporosis treatment. Genotype-based drug selection reduced adverse reactions from 14 to two cases. Conclusion: These findings improve clinical treatment efficacy and guide rational drug use for osteoporosis patients.
[Box: see text].
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Frecuencia de los Genes , Osteoporosis , Receptores de Calcitriol , Humanos , Osteoporosis/genética , Osteoporosis/tratamiento farmacológico , Receptores de Calcitriol/genética , Femenino , Persona de Mediana Edad , Frecuencia de los Genes/genética , Anciano , Masculino , Genotipo , Conservadores de la Densidad Ósea/uso terapéutico , Conservadores de la Densidad Ósea/farmacología , Polimorfismo de Nucleótido Simple/genética , Adulto , Anciano de 80 o más Años , Polimorfismo Genético/genética , AlelosRESUMEN
Human milk phospholipids (HMPLs) play an indispensable role in the neurodevelopment and growth of infants. In this study, a total of 37 phospholipid fatty acid (PLFA) species and 139 phospholipid molecular species were detected from human milk and other natural phospholipid sources (including 5 animal-derived species and 2 plant species). Moreover, a similarity evaluation model for HMPLs was established, including phospholipid classes, PLFAs, and phospholipid molecular species, to evaluate their natural substitutes. The closest scores for HMPL substitute in these three dimensions was 0.89, 0.72, and 0.77, which belonged to mare milk, goat milk, and camel milk, respectively. The highest comprehensive similarity score was obtained by camel milk at 0.75, while the lowest score was observed in soybean phospholipid (0.22). Therefore, these results not only monitored the stereochemical structure of HMPLs and their substitutes, but also further provided new insights for the development of infant formulae.
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The physicochemical properties of anhydrous milk fats (AMF) often change according to different regions and seasons, inevitably affecting dry fractionation. This study analyzed the differences in the fraction yields and physicochemical characteristics of four AMFs from different sources. The results showed that single-stage dry fractionation conducted at 25 °C easily separated AMFs into liquid fractions (L25) and solid fractions (S25) via pressure filtration, both producing satisfactory yields. Moreover, all L25s exhibited few crystals with good fluidity at 25 °C, while S25s presented as semi-solids supported by ß crystal networks with a certain hardness and plasticity. However, four AMFs displayed fractionation efficiency variation, while the thermal differences among them showed no obvious correlation with those among their fractions. Generally, more trisaturated triglycerides with 48 to 54 carbon atoms in the AMF increased the S25 yield and decreased the slip melting points (SMP) of both fractions.
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This study aimed to find new strategies for enhancing the stability and texture properties of aerated emulsion by combining different animal fats with different ratios. Beef tallow (BT)/ lard (LA) were mixed at different ratios to prepare oil-in-water (O/W) emulsions, with and without aeration. The compatibility, crystallization behavior, stability, and rheology in both O/W and aerated emulsion systems prepared with BT/LA binary blends were further investigated. Larger and inhomogeneous ß' and ß crystal mixtures appeared as the BT ratio increased. Monotectic or eutectic interaction was displayed according to different BT/LA ratios, solid fat content (SFC) and temperatures. O/W emulsion prepared with BT/LA binary showed higher apparent viscosity with larger fat globules distributed as the BT ratio increased. BT had higher SFC at any given temperature and the fat globule aggregation extent was higher. Partial coalescence occurred as the LA ratio increased when SFC < 35 %. Higher foam firmness of the aerated emulsion was achieved by BT/LA binary with higher BT ratios. As a result, combining BT and LA with different ratios achieved higher emulsion stability and foam properties. This study provides a novel insight into the application of different animal fats and the improvement of high-quality whippable products.
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Grasas de la Dieta , Animales , Bovinos , Emulsiones , ReologíaRESUMEN
The effects of different pH levels and ionic strength in calcium on the stability and aeration characteristics of dairy emulsions were investigated in this study. The results revealed that the stability and aeration characteristics of the emulsion were enhanced as the pH value increased from 6.5 to 7.0 and were optimal within the pH of 6.8~7.0, while the concentration of free calcium ions (Ca2+) was 2.94~3.22 mM. With the pH subsequently fixed at 6.8 and 7.0, when the addition of CaCl2 was increased to 2.00 mM (free Ca2+ strength > 4.11 mM), stability and aeration characteristics reduced significantly, including the flocculation of fat globules, an increase in particle size, and a decrease in the zeta potential and viscosity of the O/W emulsion, all leading to an increase in interfacial protein mass and decreased overrun and foam firmness. Overall, the results indicated that pH changes and CaCl2 addition significantly influenced the stability and aeration characteristics of dairy emulsions, by influencing free Ca2+ strength, which is an important factor in determining the quality of dairy emulsions.
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Chongqing is one of the focuses of leprosy control in China. Although leprosy control in Chongqing has achieved remarkable results over the years, there are also some problems, such as recurrent epidemics and insufficient early detection in some areas. The aim of this study was to analyze the epidemiological characteristics of leprosy in Chongqing, from 1949 to 2019 and explore the potential factors sociated with cure of leprosy to provide a basis for improving leprosy prevention and treatment strategies in Chongqing. Epidemiological indicators such as incidence and prevalence rates were used to evaluate the prevalence of leprosy. The epidemiological characteristics and control situation of leprosy in patients were analyzed using demographic characteristics, diagnosis, and treatment. Survival analysis was conducted to explore factors associated with the cure of leprosy. From 1949 to 2019, 3,703 cases of leprosy were registered in Chongqing. The incidence of leprosy in the city peaked at 0.853/105 in 1960 and remained below 0.100/105 after 2003. The number of high incidence areas decreased significantly, but they were mainly concentrated in the northeast and southeast regions. The early detection rate increased yearly from 1949 to 2019, and the rate of grade 2 disability ranged from 38.2% to 21.7%, with a fluctuating downward trend after 1960. Male, young age, employment as a farmer, delayed diagnosis, and multibacillary leprosy were risk factors for leprosy cure. Chongqing should continue to strengthen leprosy monitoring to improve the early detection of leprosy and focus on sociated risk factors to carry out multiple strategies.
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Lepra Multibacilar , Lepra , Humanos , Masculino , Lepra/diagnóstico , Lepra/tratamiento farmacológico , Lepra/epidemiología , Ciudades , China/epidemiología , Incidencia , Brasil/epidemiologíaRESUMEN
Camel milk has unique compositional, functional and therapeutic properties compared to cow's milk and also contains many protective proteins with anti-cancer, anti-diabetic and anti-bacterial properties. In this experiment, fresh camel milk was heat-treated at different temperatures and times, and the changes in Millard reaction products were analyzed. Meanwhile, headspace-gas chromatography-ion migration spectrometry (HS-GC-IMS), electronic nose and electronic tongue were used to analyze the changes of volatile components in camel milk after different heat treatments. The results showed that the Maillard reaction was more severe with the increase of heat treatment, and the contents of furosine and 5-hydroxymethylfurfural increased significantly when the heat treatment temperature was higher than 120°C. HS-GC-IMS results showed that the contents of aldehydes and ketones increased obviously with the increase of heat treatment degree. The study clarifies the effects of different heat treatment degrees on Maillard reaction degree and flavor of camel milk, which has practical production guidance significance for the research and industrialization of liquid camel milk products.
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Equol is the most potent soy isoflavone metabolite and is produced by specific intestinal microorganisms of mammals. It has promising application possibilities for preventing chronic diseases such as cardiovascular disease, breast cancer, and prostate cancer due to its high antioxidant activity and hormone-like activity. Thus, it is of great significance to systematically study the efficient preparation method of equol and its functional activity. This paper elaborates on the metabolic mechanism of equol in humans; focuses on the biological characteristics, synthesis methods, and the currently isolated equol-producing bacteria; and looks forward to its future development and application direction, aiming to provide guidance for the application and promotion of equol in the field of food and health products.
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OBJECTIVE: To compare the clinical efficacy between visual trephine arthroplasty assisted percutaneous transforaminal endoscopic discectomy (VPTED) and traditional percutaneous transforaminal endoscopic discectomy(PTED) in the treatment of lumbar disc herniation. METHODS: The clinical data of 60 patients with lumbar disc herniation admitted from June 2019 to December, 2020 was retrospectively analyzed. There were 38 males and 22 females, aged from 26 to 58 years old with an average of (43.63±8.48) years, 47 cases were on L4,5 segment and 13 cases were on L5S1 segment. Among them, 32 were treated with VPTED (group A) and 28 were treated with traditional PTED (group B). The general conditions of all the patients were recorded, including intraoperative fluoroscopy times, operation time, hospital stay and surgical complications during follow-up. The arthroplasty area ratio was observed by sagittal CT at the middle level of the intervertebral foramen. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score of low back pain, Oswestry disability index (ODI) were used to evaluate the clinical efficacy between two groups. RESULTS: All patients were followed up from 9 to 15 months with an average of (12.10±1.16) months. There was no statistical difference of preoperative general data between two groups. The operation time, fluoroscopy times and hospital stay were (70.47±5.87) min, (13.66±1.34) times and (6.31±0.69) d in group A, and (90.71±7.66) min, (22.82±2.48) times and (6.54±0.92) d in group B. The operation time and intraoperative fluoroscopy times in group A were lower than those in group B(P<0.05). There was no significant difference in hospital stay between two groups (P>0.05). No obvious surgical complications were found during the follow-up in both groups. The arthroplasty area ratio in group A was (29.72±2.84)% and (29.57±2.20)% in group B, respectively, with no significant difference (P>0.05). There was no significant difference in VAS, ODI and JOA score between two groups before operation and at the final follow-up(P>0.05), but the final follow-up was significantly improved(P<0.05). CONCLUSION: The two surgical methods have definite clinical efficacy in the treatment of lumbar disc herniation. Visual trephine arthroplasty assisted percutaneous transforaminal endoscopic discectomy has the advantages of high efficiency and rapidity when establishing the channel, and can significantly reduce the operation time and intraoperative fluoroscopy times.
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Discectomía Percutánea , Desplazamiento del Disco Intervertebral , Masculino , Femenino , Humanos , Adulto , Persona de Mediana Edad , Desplazamiento del Disco Intervertebral/cirugía , Estudios Retrospectivos , Vértebras Lumbares/cirugía , Endoscopía/métodos , Discectomía Percutánea/métodos , Discectomía/métodos , Resultado del Tratamiento , ArtroplastiaRESUMEN
Milk phospholipids (PLs) are critical components of infant growth. This study aimed to discover PL in mature human milk (HM) from China (n = 201) and mainly assessed the effect caused by sampled regions. The average total PL concentration was quantified from 3.65 to 11.25 mg per g of lipid, and the major PL class identified was sphingomyelin (SM, 38.06-47.62 %), followed by phosphatidylcholine (PC, 29.61-34.39 %), and phosphatidylethanolamine (PE, 10.54-24.46 %). In addition, the 36:2 (18:0/18:2), 38:6 (16:0/22:6), 40:1 (d18:1/22:0), and 42:2 (d18:1/24:1) were the most abundant molecular species identified in glycerophospholipid and SM molecular species respectively. Some PL molecular species were strongly related with region of sampling, like lysophosphatidylinositol 18:1 was only detected in Beijing. In conclusion, those findings showed that the PL molecular species and concentration of HM had significant regional diversity, and it will give the Chinese human milk database more accurate PL data.
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Glicerofosfolípidos , Leche Humana , Lactante , Humanos , Esfingolípidos , Pueblos del Este de Asia , FosfolípidosRESUMEN
Background: The relationship between retirement and health is important to the formulation of retirement related policies but is a controversial topic, perhaps because selection bias has not been well-addressed in previous studies through traditional analysis methods. Using data from the China Health and Retirement Longitudinal Study (CHARLS), this study explored the potential impact of retirement on the health of elderly Chinese individuals, adjusting for selection bias. Methods: We balanced the baseline differences between retirement groups and working groups based on nearest neighbor matching and genetic matching with a generalized boosted model (GBM), and regression analysis was used to evaluate the impact of retirement on the health of elderly individuals. Results: No significant difference was found in any of the covariates between the two groups after matching. Genetic matching performed better than nearest neighbor matching in balancing the covariates. Compared to the working group, the retirement group had a 0.78 (95% CI: 0.65-0.94, P = 0.026) times higher probability of self-reported physical pain, a 0.76 (95% CI: 0.62-0.93, P = 0.023) times higher probability of depression, and a 0.57-point (95% CI: 0.37-0.78, P < 0.001) improvement in cognitive status score. Among male, the retirement group had a 0.89-point (95% CI: 0.45-1.33, P < 0.001) improvement in cognitive status score for low education, a 0.65 (95% CI: 0.46-0.92, P = 0.042) times higher probability of self-reported physical pain for middle education. For female with low education, the cognitive status of the retirement group was significantly higher by 0.99 points (95% CI: 0.42-1.55, P = 0.004), the probability of depression was 0.56 (95% CI: 0.36-0.87, P = 0.031) times higher in the retirement group than in the working group. There was no difference for the middle and high education. Conclusion: Retirement can exert a beneficial effect on the health of elderly individuals. Therefore, the government and relevant departments should consider this potential effect when instituting policies that delay retirement.
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Dolor , Jubilación , Humanos , Masculino , Femenino , Anciano , Jubilación/psicología , Estudios Longitudinales , Puntaje de Propensión , China/epidemiologíaRESUMEN
Objectives: This study aimed to describe the HIV/AIDS knowledge, sexual attitudes, and sexual behaviors of young students (14-25 years) in Chongqing, China, and to examine their use of preventive services and related factors. Method: A cross-sectional study was conducted with students from 67 schools from December 2019 to June 2021. The chi-square test, non-parametric test to assess the differences between respondents with different characteristics in the above aspects. Additionally, univariate and multivariate logistic regression analyses were conducted to examine factors associated with the awareness of HIV/AIDS knowledge. Confidence intervals without crossover or P < 0.05 was considered significant. Results: A total of 31,782 participants were included in the study. A total of 62.62% of the respondents were considered to be aware of basic HIV/AIDS knowledge, including 78.44%, 62.15%, and 52.08% in undergraduate colleges, junior colleges and secondary vocational schools, respectively. In total, 60.96% of males and 29.42% of females accepted premarital sex, 15.49% of males and 6.18% of females reported being sexually experienced, and only 57.18% of the students used condoms every time they had sex. The percentage of condom use among students who were aware of HIV/AIDS knowledge was higher than that among students who were not aware. A total of 85.60% of the students thought they needed HIV/AIDS prevention and control knowledge, and 94.60% thought more health education activities on HIV/AIDS prevention needed to be conducted in schools. Entrance education, lectures or consultation hotlines, WeChat official accounts and other media platforms were rated as the most acceptable HIV/AIDS prevention education methods. Conclusion: These respondents lacked knowledge about HIV/AIDS, and an increasing number of students show an open attitude toward premarital sex and engage in risky sexual behaviors. It is urgent to enhance and widely disseminate comprehensive HIV/AIDS and sexual health education in multiple formats.
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Síndrome de Inmunodeficiencia Adquirida , Masculino , Femenino , Humanos , Síndrome de Inmunodeficiencia Adquirida/prevención & control , Estudios Transversales , Conocimientos, Actitudes y Práctica en Salud , Estudiantes , ChinaRESUMEN
The current study aimed to compare the effectiveness of two extraction techniques, namely simultaneous distillation-extraction (SDE) and solid-phase microextraction (SPME), in evaluating key aroma compounds in butters. Volatile compounds' contributions to butter flavors were evaluated employing both odor active values (OAVs) and gas chromatography olfactometry (GC-O). The results showed that the species of volatile compounds detected by the two techniques were almost the same, whereas their volatile profiles were obviously different. Using SDE method, methyl ketones took up the largest proportion of the volatile compounds, followed by fatty acids. Using SPME method, the most abundant compounds were the fatty acids, followed by lactones. More methyl ketones were detected in the SDE extract owing to lipid degradation as a consequence of the high temperature during extraction. Lactones were considered to be the key aroma compounds, especially δ-decalactone, which was identified by both OAVs and GC-O.
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The experiments reported in this study provided a more comprehensive insight into the effect of chemical composition on the crystallization behavior of milk fat (MF). MF was fractionated between 20 and 40 °C into nine fractions with different melting points and was first subjected to the heating step (L20, L30, L40, and S40) followed by the cooling phase (SS40, SL40, SS30, SL30, and LL40). Furthermore, the species of fatty acids (FAs) and triglycerides (TAGs) of the MF fractions were identified. The thermodynamics, crystallization behavior, and polymorphs were determined using differential scanning calorimetry, pulsed nuclear magnetic resonance, and X-ray diffraction, respectively. The results indicated that L40 yielded the highest percentage (â¼35% of the total MF) of all the fractions. Enthalpies of the melting and crystallization processes of solid fat content in this study were related to the different FA and TAG compositions of MF and its fractions. High melting fractions (HMFs) were enriched with long-chain saturated fatty acids and tri-saturated (S3) TAGs, and low melting fractions (LMFs) were enriched with short-chain unsaturated FAs and tri-unsaturated (U3) TAGs. Moreover, the various nucleation mechanisms of MF fractions were identified according to the Avrami equation. The polymorphic transformation from a ß' form of double chain length structures to a ß form of triple chain length occurred in the native MF and HMFs, whereas the LMFs displayed almost no crystals. PRACTICAL APPLICATION: This study represented the first time that nine fractions were obtained using MF fractionation via a heating step, followed by a cooling phase. Furthermore, the chemical composition of MF fractions was investigated. The results obtained from this study might be of specific value in understanding the functional properties of fat-based dairy food in both storage conditions and real-time applications.