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Yogurt, a traditional fermented dairy product, is made with a starter that contains Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. The aim of this study was to investigate the effects of different concentrations of epigallocatechin gallate (EGCG; 0, 0.5, 1.0, 3.0, and 5.0 mg/mL) on the growth, metabolism, and acid production of lactic acid bacteria, as well as the texture, stability, and antioxidant activity of fermented milk (yogurt). The results showed that a low concentration of EGCG had no significant effect on the acid production capacity of the starter or on the water-holding capacity of the yogurt but did increase its viscosity. A high concentration (5.0 mg/mL) of EGCG delayed the acid production rate of the starter and decreased the water-holding capacity, but significantly increased the antioxidant activity of yogurt. The addition of EGCG significantly increased the hardness of yogurt. Therefore, EGCG can improve the texture of fermented milk and enhance its antioxidant activity and stability, thus improving the overall quality of yogurt.
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Lactobacillus delbrueckii , Leche , Ácidos/metabolismo , Animales , Antioxidantes/metabolismo , Catequina/análogos & derivados , Fermentación , Lactobacillus delbrueckii/metabolismo , Leche/química , Streptococcus thermophilus/metabolismo , Agua/análisis , Yogur/microbiologíaRESUMEN
OBJECTIVE: To study the effect of milk enriched with phytosterol ester on blood cholesterol. METHODS: Participants with hypercholesterolemia were recruited from community health center and randomly assigned to 3 groups: milk enriched with phytosterol ester group( PS group, n = 59), normal milk group( n = 58) and non-dairy group( n = 62). The intervention lasted for 2 months. At baseline, all subjects in the 3groups received health education on prevention and control of hypercholesterolemia. For PS and normal milk groups, subjects consumed 500 g milk per day, the intake ofphytosterol in PS group was 1. 58 g / d. For non-dairy group, subjects did not consume any dairy products during the trial. Subjects were assessed on their physical activity level and blood cholesterols were measured during monthly follow-up. RESULTS: Finally 157 subjects completed the trial. By the end of the first month, the TC and LDL-C levels of PS group were significantly lower than that of normal milk group. After adjustment, there was no significant difference between baseline and 1-month TC levels in PS group. The levels of TG and HDL-C in PS group were significantly increased while the LDL-C level was significantly decreased after 1-month intervention. Compared with normal milk and nondairy groups, no differences were observed for these four indicators. After 2-month intervention, the TC and LDL-C levels of PS group were significantly lower than that of normal milk and non-dairy groups. The levels of TC and LDL-C in PS group were significantly reduced compared to baseline levels after adjustment. TG level was increased while HDL-C level was unchanged. Compared with normal milk and non-dairy groups, the levels of TC and LDL-C in PS group were significantly declined while no significant difference was observed for TG and HDL-C levels. CONCLUSION: s Milk enriched with phytosterol ester has a notable effect on lowering TC and LDL-C levels in subjects with hypercholesterolemia.
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Colesterol/sangre , Hipercolesterolemia/dietoterapia , Leche/química , Fitosteroles/farmacología , Animales , HDL-Colesterol , LDL-Colesterol/sangre , Método Doble Ciego , Humanos , Fitosteroles/administración & dosificaciónRESUMEN
The objective of this study was to investigate the potential of Lacticaseibacillus rhamnosus L08 (L. rhamnosus L08) to enhance the functionality, improve the taste, and explore efficient storage methods of blue honeysuckle juice (BHJ). The fermentation process resulted in an increase in the levels of polyphenols, flavonoids, and anthocyanins in blue honeysuckle juice, which was attributed to the action of ß-glucosidase on specific phenolic compounds, namely Cyanidin-3-Glucoside and Quinic acid. The increase in phenolic content resulted in an enhancement of the antioxidant capacity of BHJ. The fermentation processed, utilizing L. rhamnosus L08, not only enhanced the flavor and taste of BHJ, but also mitigated its bitter aftertaste while minimizing the loss of bioactive components during storage. In conclusion, this study demonstrated a potential avenue for enhancing the commercial value and dietary significance of this lesser-known superfruit, with fermented BHJ emerging as a promising innovation in the field of functional foods.
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The impact of milk on bone health in rural preschoolers is under-researched. This study, through a clinical trial and a meta-analysis, finds that milk supplementation enhances forearm and calcaneus bone acquisition in children, supporting the benefits of daily milk consumption. PURPOSE: This study evaluated the impact of dairy supplementation on bone acquisition in children's limbs through a cluster-randomized controlled trial and a meta-analysis. METHODS: The trial involved 315 children (4-6 year) from Northwest China, randomized to receive either 390 ml of milk daily (n = 215) or 20-30 g of bread (n = 100) over 12 months. We primarily assessed bone mineral density (BMD) and content (BMC) changes at the limbs, alongside bone-related biomarkers, measured at baseline, the 6th and 12th months. The meta-analysis aggregated BMD or BMC changes in the forearm/legs/calcaneus from published randomized trials involving children aged 3-18 years supplemented with dairy foods (vs. control group). RESULTS: Of 278 completed the trial, intention-to-treat analysis revealed significant increases in BMD (4.05% and 7.31%) and BMC (4.69% and 7.34%) in the left forearm at the 6th and 12th months in the milk group compared to controls (P < 0.001). The calcaneus showed notable improvements in BMD (2.01%) and BMC (1.87%) at 6 months but not at 12 months. Additionally, milk supplementation was associated with beneficial changes in bone resorption markers, parathyroid hormone (- 12.70%), insulin-like growth factor 1 (6.69%), and the calcium-to-phosphorus ratio (2.22%) (all P < 0.05). The meta-analysis, encompassing 894 children, indicated that dairy supplementation significantly increased BMD (SMD, 0.629; 95%CI: 0.275, 0.983) and BMC (SMD, 0.616; 95%CI: 0.380, 0.851) (P < 0.05) in the arms, but not in the legs (P > 0.05). CONCLUSION: Milk supplementation significantly improves bone health in children's forearms, underscoring its potential as a strategic dietary intervention for bone development. Trial registration NCT05074836.
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Densidad Ósea , Suplementos Dietéticos , Niño , Preescolar , Femenino , Humanos , Masculino , Densidad Ósea/efectos de los fármacos , Desarrollo Óseo/fisiología , Calcáneo/diagnóstico por imagen , China , Antebrazo , Leche , AdolescenteRESUMEN
Herein, we explored the effects of Poria cocos extract, protein powder mixture, and their combined intervention on weight loss in high-fat diet (HFD)-induced obese mice. Male C57BL/6J mice were selected and fed a HFD for 8 weeks; obese mice that were successfully modeled were divided into modeling and five intervention groups, and given the corresponding treatment for 10 weeks. Body weight, fat, and muscle tissue, blood glucose, lipids, inflammatory factors, and other glucose and lipid metabolism-related indicators were measured to evaluate the effect of P. cocos and protein powder intervention on weight loss in obese mice. The body weight of the intervention group was reduced compared with the HFD group. Fat content of mice in F3PM group decreased significantly (p < .05). Levels of blood glucose, lipids, adiponectin, leptin, and inflammatory factors, including interleukin-1 ß and tumor necrosis factor- α showed improvement. Lipoprotein lipase (lower about 2.97 pg/ml, vs. HFD mice 10.65 mmoL/ml) and sterol regulatory element-binding transcription factor (lower about 1413.63 pg/ml, vs. HFD mice 3915.33 pg/ml) levels in liver tissue were decreased. The respiratory exchange rate (RER) of mice in the HFD and subject intervention groups had no circadian rhythm and was maintained at approximately 0.80. The protein powder mixture (PM) group had the lowest RER (p < .05), the P. cocos extract (FL) and F1PM groups had similar RER to the HFD group (p < .05), and the F2PM group had a higher RER than the HFD group (p < .05). And food intake and energy metabolism returned to circadian rhythm, with an increase in the dose of P. cocos extract, the feeding rhythms of F1PM, F2PM, and F3PM were closer to that of the normal diet (ND) group. Feeding intervention with P. cocos and protein powder improved fat distribution, glucolipid metabolism, and energy metabolism, with the combination of F3PM showing more diverse benefits.
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Introduction: Anxiety disorders continue to prevail as the most prevalent cluster of mental disorders following the COVID-19 pandemic, exhibiting substantial detrimental effects on individuals' overall well-being and functioning. Even after a search spanning over a decade for novel anxiolytic compounds, none have been approved, resulting in the current anxiolytic medications being effective only for a specific subset of patients. Consequently, researchers are investigating everyday nutrients as potential alternatives to conventional medicines. Our prior study analyzed the antianxiety and memory-enhancing properties of the combination of Walnut Peptide (WP) and Casein Peptide (CP) in zebrafish. Methods and Results: Based on this work, our current research further validates their effects in mice models exhibiting elevated anxiety levels through a combination of gavage oral administration. Our results demonstrated that at 170 + 300 mg human dose, the WP + CP combination significantly improved performances in relevant behavioral assessments related to anxiety and memory. Furthermore, our analysis revealed that the combination restores neurotransmitter dysfunction observed while monitoring Serotonin, gamma-aminobutyric acid (GABA), dopamine (DA), and acetylcholine (ACh) levels. This supplementation also elevated the expression of brain-derived neurotrophic factor mRNA, indicating protective effects against the neurological stresses of anxiety. Additionally, there were strong correlations among behavioral indicators, BDNF (brain-derived neurotrophic factor), and numerous neurotransmitters. Conclusion: Hence, our findings propose that the WP + CP combination holds promise as a treatment for anxiety disorder. Besides, supplementary applications are feasible when produced as powdered dietary supplements or added to common foods like powder, yogurt, or milk.
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Coix seed extract (CSE) and probiotics have been reported to regulate glycolipid metabolism through different modes of action. We tested the effects of CSE, Lactobacillus paracasei K56, and their combination to determine whether they have synergistic effects on glycolipid metabolism of obese mice. We fed male C57BL/6J mice with high-fat diet for 8 weeks to establish an obesity model. The obesity mice were selected and divided into five groups: the model control group and four intervention groups. After 10 weeks of continuous gavage intervention, the mice in the intervention groups exhibited lower body weight (lower about 2.31-4.41 g, vs. HFD 42.25 g, p < 0.01), and epididymal (lower about 0.58-0.92 g, vs. HFD 2.50 g, p < 0.01) and perirenal fat content (lower about 0.24-0.42 g, vs. HFD 0.88 g, p < 0.05); decreased fasting blood glucose, total cholesterol, triglycerides, and VLDL; and increased HLDL, respiratory exchange ratio, energy expenditure, and amount of exercise performed. K56 + CSE-combined intervention groups were more effective in lowering blood glucose, IL-1ß, and TNF-α levels than the CSE and K56 alone interventions. The content of fatty acid synthase and SREBP-1c protein in liver tissue was lower. The combination has synergistic effects on weight control, fat reduction, and blood glucose regulation by improving the chronic inflammatory state and reducing the content of lipid synthesis-related enzymes of obese mice, which can hinder chronic disease progression. PRACTICAL APPLICATION: Coix seed extract can be used in obese people to regulate abnormal glucose and lipid metabolism and delay the development of chronic diseases.
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Coix , Lacticaseibacillus paracasei , Ratones , Masculino , Animales , Ratones Obesos , Glucemia/metabolismo , Ratones Endogámicos C57BL , Obesidad/metabolismo , Metabolismo de los Lípidos , Hígado/metabolismo , Dieta Alta en Grasa/efectos adversos , GlucolípidosRESUMEN
Dairy foods are crucial for adequate calcium intake in young children, but scarce data are available on the effects of formula milk on bone acquisition. This cluster-randomized controlled trial investigated the effects of the supplementation of formula milk on bone health in rural children accustomed to a low-calcium diet between September 2021 and September 2022. We recruited 196 healthy children aged 4-6 years from two kindergartens in Huining County, Northwest China. A class-based randomization was used to assign them to receive 60 g of formula milk powder containing 720 mg calcium and 4.5 µg vitamin D or 20-30 g of bread per day for 12 months, respectively. Bone mineral density (BMD) and bone mineral content (BMC) at the left forearm and calcaneus, bone biomarkers, bone-related hormones/growth factors, and body measures were determined at baseline, 6, and 12 months. A total of 174 children completed the trial and were included in the analysis. Compared with the control group, formula milk intervention showed significant extra increments in BMD (3.77% and 6.66%) and BMC (4.55% and 5.76%) at the left forearm at 6th and 12th months post-intervention (all p < 0.001), respectively. Similar trends were observed in BMD (2.83%) and BMC (2.38%) in the left calcaneus at 6 months (p < 0.05). The milk intervention (vs. control) also showed significant changes in the serum concentrations of osteocalcin level (-7.59%, p = 0.012), 25-hydroxy-vitamin-D (+5.54%, p = 0.001), parathyroid hormone concentration (-15.22%, p = 0.003), and insulin-like growth factor 1 (+8.36%, p = 0.014). The percentage increases in height were 0.34%, 0.45%, and 0.42% higher in the milk group than in the control group after 3-, 6-, and 9-month intervention, respectively (p < 0.05). In summary, formula milk supplementation enhances bone acquisition at the left forearm in young Chinese children.
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Calcio , Leche , Humanos , Niño , Preescolar , Animales , Calcio/farmacología , Pueblos del Este de Asia , Huesos , Calcio de la Dieta/farmacología , Densidad Ósea , Vitamina D/farmacología , Suplementos DietéticosRESUMEN
Objectives: Obesity is often associated with glucolipid and/or energy metabolism disorders. Ascophyllum nodosum extract (seaweed extract, SE) and Camellia sinensis-leaf extract (tea extract, TE) have been reported to promote positive metabolic effects through different mechanisms. We investigated the effects of SE and TE on metabolic homeostasis in diet-induced obese mice and discussed their functional characteristics. Methods: Male C57BL/6J mice fed with high-fat diets for 8 weeks were established as obese models and subsequently divided into different intervention groups, followed by SE, TE, and their joint interventions for 10 weeks. Body weight and food intake were monitored. Fasting glucose and oral glucose tolerance tests were interspersed during the experiment. After the intervention, the effects on obesity control were assessed based on body composition, liver pathology section, blood lipids and glucose, respiratory exchange ratio (RER), energy expenditure (EE1, EE2, and EE3), inflammatory factors, lipid anabolism enzymes, and gut flora of the obese mice. Results: After continuous gavage intervention, the mice in the intervention groups exhibited lower body weight (lower ~4.93 g, vs. HFD 38.02 g), peri-testicular fat masses (lower ~0.61 g, vs. HFD 1.92 g), and perirenal fat masses (lower ~0.21 g, vs. HFD mice 0.70 g). All interventions prevented diet-induced increases in plasma levels of glucose, adiponectin, leptin, and the inflammatory factors IL-1ß and TNF-α. The RER was modified by the interventions, while the rhythm of the RER was not. Blood lipids (total cholesterol, triglycerides, and LDL) decreased and were associated with lower lipid anabolism enzymes. In addition, the SE and TE interventions altered the structure and abundance of specific flora. Different interventions inhibited the growth of different genera positively associated with obesity (Escherichia-Shigella, Helicobacter, etc.) and promoted the growth of Akkermansia and Bacteroides, thus affecting the chronic inflammatory state. Conclusion: SE and TE both have synergistic effects on weight control and glucolipid metabolism regulation by improving insulin sensitivity and reducing lipid synthesis-related enzyme expression, whereas the combination of SE and TE (3:1) has a better effect on regulating energy metabolism and inhibiting chronic inflammation.
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Introduction: Brain development during infancy is crucial for later health and development. Although Milk Fat Globule Membrane (MFGM) has been demonstrated to enhance brain development, further investigation is needed to determine the optimal dose. Methods: In this study, 80 piglets aged 2 days were randomly assigned to four groups: Control group, MFGM-L (1.74 g MFGM per 100 g diet), MFGM-M (4.64 g MFGM per 100 g diet), and MFGM-H (6.09 g MFGM per 100 g diet). Daily body weight and milk intake of the piglets were recorded until 31 days postnatal. Learning and memory abilities were evaluated using the spatial T-maze test on day 15. MRI analysis was conducted to assess functional and structural changes in brain tissues. Additionally, mRNA and protein expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NTF-3) in the hippocampus and prefrontal cortex were evaluated. Results: The results indicated that the MFGM supplemented diet significantly improved the accuracy of the piglets in the T-maze test, with the MFGM-L group exhibiting the best performance. MRI showed no volumetric differences in the gray and white matter between the groups. However, the fractional anisotropy in the left and right hippocampus of piglets in the MFGM-L group was significantly higher than in the other three groups. Furthermore, there was a strong correlation between the accuracy of the T-maze test and hippocampal fractional anisotropy. Discussion: The MFGM supplemented diet also increased the expression of BDNF in the cerebral cortex. However, the changes in BDNF were not consistent with the results of the T-maze test. In conclusion, adding 1.74 g MFGM per 100 g diet can significantly improve neonatal piglets' learning and memory abilities, potentially by enhancing the connection of white matter fiber bundles in the brain.
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It has been well known that the influxing meteoric water can hydrothermally lower oxygen and hydrogen isotopes of rocks and/or minerals during continental magmatic or metamorphic processes in certain appropriate cases. Its opposite, however, is not implicitly true and needs independent testing. In terms of a novel procedure recently proposed for dealing with thermodynamic re-equilibration of oxygen isotopes between constituent minerals and water from fossil hydrothermal systems, the initial oxygen isotopes of water ([Formula: see text]) are theoretically inverted from the early Cretaceous post-collisional granitoids and Triassic gneissic country rock across the Dabie orogen in central-eastern China. Despite ancient meteoric waters with low [Formula: see text] value down to - 11.01 ± 0.43 (one standard deviation, 1SD), oxygen isotopes of hydrothermally altered rock-forming minerals from a granitoid were unexpectedly but concurrently lowered by an evolved magmatic water with mildly high [Formula: see text] value of 2.81 ± 0.05 at 375 °C with a water/rock (W/R)c ratio of 1.78 ± 0.20 for the closed system. The lifetime of fossil hydrothermal systems studied herein is kinetically constrained to no more than 1.2 million years (Myr) via surface-reaction oxygen exchange in the late-stage of continental magmatism or metamorphism. Thereby, caution should be paid when lowered oxygen isotopes of hydrothermally altered rocks and/or minerals were intuitively and/or empirically inferred from the external infiltration of the purely meteoric water with a low [Formula: see text] value alone.
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Anxiety disorders are the most common mental disorders and, without proper treatment, may lead to severe conditions: e.g., somatic disorders or permanent damage to central nervous system. Although there are drugs in clinical trials, this study focuses on exploring the efficacy of nutrients in treating these diseases. We built different zebrafish models and screened several nutrient combinations for their antianxiety, antioxidant, neuro-protecting, and memory-improving activities. Our results showed that the combinations of nutrients (e.g., Walnut Peptides + Theanine at 14.2 + 33.3 µg/ml) have similar or better activities than the positive control drugs. In addition, we discovered that the effects of the nutrients in the above four aspects were universal and highly related. This study is noteworthy as it suggested that nutrients could be healthier and greener drug alternatives and provide similar or better universal treatments for anxiety and related conditions.
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Coix seed extract (CSE) and probiotics have been reported to regulate glycolipid metabolism via different modes of action. We tested the effects of CSE, Bifidobacterium BPL1, and their combination to determine their effects on glycolipid metabolism in obese mice. Male C57BL/6J mice were fed a high-fat diet for 8 weeks to establish an obesity model. Obese mice were selected and divided into four groups: the model control group and three intervention groups. After 10 weeks of continuous gavage intervention, the mice in the intervention groups exhibited lower body weight (lower about 2.31 g, vs. HFD mice 42.23 g) and epididymal (lower about 0.37 g, vs. HFD mice 2.5 g) and perirenal fat content (lower about 0.47 g, vs. HFD mice 0.884 g); decreased fasting blood glucose, total cholesterol, triglycerides, and VLDL; and increased HLDL, respiratory exchange ratio, energy expenditure, and amount of exercise performed. CSE, BPL1 and their combination can effectively control the weight gain in obese mice, reduce fat content, and regulate blood lipids and abnormal blood sugar. These results may be related to reduce the chronic inflammatory states, improve energy metabolism, exercise, relieve insulin sensitivity, and reduce lipid synthesis via the intervention of CSE, BPL1 and their combination. Compared with the single use of CSE alone, the combination of CSE + BPL1 can better exert the regulation function of intestinal flora, and change in the abundance of bacteria that could improve the level of inflammatory factors, such as increasing Bifidobacterium, reducing Lactococcus. Compared with the use of BPL1 alone, the combination of CSE and BPL1 can better regulate pancreatic islet and improve blood sugar. CSE may act directly on body tissues to exert anti-inflammatory effects. BPL1 and CSE + BPL1 may improve the structure and function of the intestinal flora, and reduce tissue inflammation.
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BACKGROUND: L-theanine (L-THE), a natural amino acid found in green tea, has been shown to improve anxiety and sleep. Neumentix proprietary spearmint extract (PSE), which is commonly found in beverage flavoring a pharmaceutical, also has a wide range of health benefits, including cognitive performance improvement. METHODS: Four experiments tested the effects of L-THE and PSE on sleep: a direct sleeping test, pentobarbital-induced sleeping test, sub-hypnotic pentobarbital-induced sleeping test, and sodium barbital-induced sleeping test. Presence of neurotransmitters in brain tissue was detected by liquid chromatography mass spectroscopy (HP LC-MS) during these studies. RESULTS: Pentobarbital-induced sleeping and sodium barbital-induced sleeping tests examined the potential effect of L-THE/PSE mixture on synergistic sleep, while neurotransmitter levels in the brain were determined by the high performance liquid chromatography/mass spectroscopy (HPLC/MS) method. L-THE and L-THE/PSE mixture showed increased sleep duration and shortened sleep latency when co-administrated with pentobarbital or sodium barbital. The mixture also increased sleeping rate when co-administrated with the pentobarbital at sub-hypnotic dose. Additionally, the L-THE, PSE and L-THE/PSE mixture significantly increased the concentrations of acetylcholine (Ach), γ-aminobutyric acid (GABA), and decreased the concentration of serotonin (5-HT) in the brain. CONCLUSIONS: These data demonstrated that L-THE/PSE mixture regulates sleep disorders via the GABA receptor and neurotransmitter systems.
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Neurotransmisores , Ácido gamma-Aminobutírico , Animales , Encéfalo , Glutamatos , Ratones , SueñoRESUMEN
BACKGROUND: γ-aminobutyric acid (GABA) is a naturally occurring non-protein amino acid in the nervous system and has a wide range of physiological functions in the body. Walnut peptide (WP) contains high levels of arginine, aspartic acid, and glutamate, and has been shown to improve cognitive deficits and memory impairment in mice, while restoring antioxidant enzyme levels and reducing brain inflammatory mediators. METHODS: This study investigated the effects of GABA and WP, either alone or in combination, on sleep disturbances in mice. The pentobarbital-prolonged sleep test, pentobarbital-threshold sleep test, and barbital-induced sleep test were conducted to assess the effects of GABA and WP on sleep quality by gavage for 30 days as follows: GABA (102.25 mg/kg), WP (102.25 mg/kg), GABA (33.95, 102.25, 306.75 mg/kg)/WP (102.25 mg/kg) mixture. Furthermore, neurotransmitter tests were performed using mice brain tissue to investigate the possible mechanisms of GABA and WP on sleep status. RESULTS: The results showed that the combined use of GABA and WP significantly increased sleep duration compared with single administration of either WP or GABA. Increasing doses of GABA in mice treated with combined GABA and WP elevated the sleep rate to 50.00%, 64.28%, and 64.28%, respectively, compared to mice treated with GABA alone (35.71%) or mice treated with WP alone (28.57%). In mice that received a combination of GABA and WP orally, the latency time was significantly decreased after 30 days compared to control mice (P<0.05). Additionally, in mice treated with GABA, WP, or the combination of GABA and WP, the concentrations of GABA and acetylcholine (Ach) in the brain were significantly elevated and the concentration of serotonin (5-HT) was decreased compared to untreated mice. CONCLUSIONS: These results demonstrated that the combined administration of GABA and WP could prolong the sleep duration, increase sleep rate, and shorten the sleep latency more effectively than the administration of either GABA or WP alone. The mechanisms of action may be related to the regulation of neurotransmitters in the brain tissue by the combination of GABA and WP.
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Juglans , Animales , Ratones , Pentobarbital , Péptidos , Sueño , Ácido gamma-AminobutíricoRESUMEN
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
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Crustal components may be incorporated into continental basalts by either shallow contamination or deep mixing. While the former proceeds at crustal depths with common preservation of refractory minerals, the latter occurs at mantle depths with rare survival of relict minerals. Discrimination between the two mechanisms has great bearing to subcontinental mantle geochemistry. Here we report the occurrence of relict zircons in Cenozoic continental basalts from eastern China. A combined study of zircon U-Pb ages and geochemistry indicates that detrital zircons were carried by terrigenous sediments into a subcontinental subduction zone, where the zircon were transferred by fluids into the magma sources of continental basalts. The basalts were sampled from three petrotectonic units with distinct differences in their magmatic and metamorphic ages, making the crustal contamination discernible. The terrigenous sediments were carried by the subducting oceanic crust into the asthenospheric mantle, producing both soluble and insoluble materials at the slab-mantle interface. These materials were served as metasomatic agents to react with the overlying mantle wedge peridotite, generating a kind of ultramafic metasomatites that contain the relict zircons. Therefore, the occurrence of relict zircons in continental basalts indicates that this refractory mineral can survive extreme temperature-pressure conditions in the asthenospheric mantle.
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Since water is only composed of oxygen and hydrogen, δ18O and δ2H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known. Here we show that two sources of externally derived water interactions were revealed by oxygen isotopes for the gneissic country rocks intruded by the early Cretaceous postcollisional granitoids. Inverse modellings indicate that the degree of disequilibrium (doD) of meteoric water interactions was more evident than that of magmatic one (-65 ± 1o vs. -20 ± 2°); the partial reequilibration between quartz and alkali feldspar oxygen isotopes with magmatic water was achieved at 340 °C with a water/rock (W/R) ratio of about 1.2 for an open-hydrothermal system; two-stage meteoric water interactions were unraveled with reequilibration temperatures less than 300 °C and W/R ratios around 0.4. The lifetime of fossil magmatic hydrothermal system overprinted on the low zircon δ18O orthogneissic country rocks was estimated to maintain up to 50 thousand years (Kyr) through oxygen exchange modellings. Four-stage isotopic evolutions were proposed for the magmatic water interacted gneiss.
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Findings of coesite and microdiamond in metamorphic rocks of supracrustal protolith led to the recognition of continental subduction to mantle depths. The crust-mantle interaction is expected to take place during subduction of the continental crust beneath the subcontinental lithospheric mantle wedge. This is recorded by postcollisional mafic igneous rocks in the Dabie-Sulu orogenic belt and its adjacent continental margin in the North China Block. These rocks exhibit the geochemical inheritance of whole-rock trace elements and Sr-Nd-Pb isotopes as well as zircon U-Pb ages and Hf-O isotopes from felsic melts derived from the subducted continental crust. Reaction of such melts with the overlying wedge peridotite would transfer the crustal signatures to the mantle sources for postcollisional mafic magmatism. Therefore, postcollisonal mafic igneous rocks above continental subduction zones are an analog to arc volcanics above oceanic subduction zones, providing an additional laboratory for the study of crust-mantle interaction at convergent plate margins.