145 research outputs found
VALUE CREATION THROUGH INTER-ORGANIZATIONAL SYSTEMS (IOS): FROM GOVERNANCE PROCESS VIEW
In this study, we seek to reveal the mechanism of value creation between firms and their partners in B2B context. An integrated conceptual model is constructed grounded in the co-creation theory and the process view, which proposes the interaction between relational assets, IOS support and governance process, as well as their impacts on co-created value. It differs from previous studies by highlighting the mediating effect of governance on value creation. Using a sample of 181 collected from China, our analysis indicates the contribution of governance to co-created value, which is generated through IOS and relational assets. In fact, the IOS support and relational assets alone don’t hold the answer to value co-creation, but they affect the mediating process and enable governance to create value. Especially, the IOS could accommodate the use of relational assets and significantly affect governance process, which is found to be fundamental in value creation. While commodity-like resources have diminishing value in co-creation, governance process with causal ambiguity, social complexity and organizational interconnectedness, becomes the main source of co-created value. Overall, our research sheds light on the key drivers of value co-creation, and provides insights to their impacts on value creation
N-acetylcysteine Protects against Apoptosis through Modulation of Group I Metabotropic Glutamate Receptor Activity
The activation of group I metabotropic glutamate receptor (group I mGlus) has been shown to produce neuroprotective or neurotoxic effects. In this study, we investigated the effects of N-acetylcysteine (NAC), a precursor of the antioxidant glutathione, on group I mGlus activation in apoptosis of glial C6 and MN9D cell lines, and a rat model of Parkinson's disease (PD). We demonstrated that NAC protected against apoptosis through modulation of group I mGlus activity. In glial C6 cells, NAC promoted phosphorylation of ERK induced by (s)-3,5- dihydroxy-phenylglycine (DHPG), an agonist of group I mGlus. NAC enhanced the group I mGlus-mediated protection from staurosporine (STS)-induced apoptosis following DHPG treatment. Moreover, in rotenone-treated MN9D cells and PD rat model, NAC protected against group I mGlus-induced toxicity by compromising the decrease in phosphorylation of ERK, phosphorylation or expression level of TH. Furthermore, the results showed that NAC prohibited the level of ROS and oxidation of cellular GSH/GSSG (Eh) accompanied by activated group I mGlus in the experimental models. Our results suggest that NAC might act as a regulator of group I mGlus-mediated activities in both neuroprotection and neurotoxicity via reducing the oxidative stress, eventually to protect cell survival. The study also suggests that NAC might be a potential therapeutics targeting for group I mGlus activation in the treatment of PD
Large Language Models for Information Retrieval: A Survey
As a primary means of information acquisition, information retrieval (IR)
systems, such as search engines, have integrated themselves into our daily
lives. These systems also serve as components of dialogue, question-answering,
and recommender systems. The trajectory of IR has evolved dynamically from its
origins in term-based methods to its integration with advanced neural models.
While the neural models excel at capturing complex contextual signals and
semantic nuances, thereby reshaping the IR landscape, they still face
challenges such as data scarcity, interpretability, and the generation of
contextually plausible yet potentially inaccurate responses. This evolution
requires a combination of both traditional methods (such as term-based sparse
retrieval methods with rapid response) and modern neural architectures (such as
language models with powerful language understanding capacity). Meanwhile, the
emergence of large language models (LLMs), typified by ChatGPT and GPT-4, has
revolutionized natural language processing due to their remarkable language
understanding, generation, generalization, and reasoning abilities.
Consequently, recent research has sought to leverage LLMs to improve IR
systems. Given the rapid evolution of this research trajectory, it is necessary
to consolidate existing methodologies and provide nuanced insights through a
comprehensive overview. In this survey, we delve into the confluence of LLMs
and IR systems, including crucial aspects such as query rewriters, retrievers,
rerankers, and readers. Additionally, we explore promising directions within
this expanding field
Weight-based Channel-model Matrix Framework provides a reasonable solution for EEG-based cross-dataset emotion recognition
Cross-dataset emotion recognition as an extremely challenging task in the
field of EEG-based affective computing is influenced by many factors, which
makes the universal models yield unsatisfactory results. Facing the situation
that lacks EEG information decoding research, we first analyzed the impact of
different EEG information(individual, session, emotion and trial) for emotion
recognition by sample space visualization, sample aggregation phenomena
quantification, and energy pattern analysis on five public datasets. Based on
these phenomena and patterns, we provided the processing methods and
interpretable work of various EEG differences. Through the analysis of
emotional feature distribution patterns, the Individual Emotional Feature
Distribution Difference(IEFDD) was found, which was also considered as the main
factor of the stability for emotion recognition. After analyzing the
limitations of traditional modeling approach suffering from IEFDD, the
Weight-based Channel-model Matrix Framework(WCMF) was proposed. To reasonably
characterize emotional feature distribution patterns, four weight extraction
methods were designed, and the optimal was the correction T-test(CT) weight
extraction method. Finally, the performance of WCMF was validated on
cross-dataset tasks in two kinds of experiments that simulated different
practical scenarios, and the results showed that WCMF had more stable and
better emotion recognition ability.Comment: 18 pages, 12 figures, 8 table
Lifetime cumulative effect of reproductive factors on stroke and its subtypes in postmenopausal Chinese women: a prospective cohort study
Background and Objectives:Â Multiple reproductive factors are associated with stroke. Little is known about the cumulative effects of reproductive factors during a reproductive life course on stroke and its subtypes, especially among female Chinese individuals. The objective of this study was to assess the associations of lifetime cumulative estrogen exposure due to reproductive factors with stroke and its etiologic subtypes among postmenopausal Chinese women.
Methods: Postmenopausal women without prior stroke at baseline (2004–2008) were selected from the China Kadoorie Biobank (CKB). Lifetime cumulative estrogen exposure due to reproductive factors was assessed using 3 composite indicators: reproductive lifespan (RLS), endogenous estrogen exposure (EEE), and total estrogen exposure (TEE). Stroke and its subtypes, ischemic stroke (IS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH), were identified through linkage to a disease registry system and health insurance data during follow-up (2004–2015). Multivariable-adjusted Cox proportional hazards regression models were applied to estimate the adjusted hazard ratio (aHR) and 95% CIs for the risk of stroke by quartiles of RLS, EEE, and TEE, respectively.
Results: A total of 122,939 postmenopausal participants aged 40–79 years without prior stroke at baseline were included. During a median follow-up period of 8.9 years, 15,139 cases with new-onset stroke were identified, including 12,853 cases with IS, 2,580 cases with ICH, and 269 cases with SAH. Compared with the lowest quartile (Q1) of RLS, the highest quartile (Q4) had a lower risk of total stroke (aHR: 0.95, 95% CI 0.92–0.98), IS (aHR: 0.95, 95% CI 0.92–0.98), and ICH (aHR: 0.87, 95% CI 0.81–0.94). Both EEE and TEE displayed a graded association with the subsequent descending risk of total stroke (aHR for Q4 vs Q1: EEE: 0.85, 95% CI 0.82–0.89; TEE: 0.87, 95% CI 0.84–0.90), IS (aHR for Q4 vs Q1: EEE: 0.86, 95% CI 0.83–0.90; TEE: 0.86, 95% CI 0.83–0.89), and ICH (EEE: 0.73, 95% CI 0.65–0.81; TEE: 0.83,95% CI 0.76–0.91), with a p for trend < 0.001 for all these associations.
Discussion:Â Individuals' cumulative estrogen exposure due to reproductive factors could potentially be a valuable indicator for risk stratification of stroke events after menopause
Myoglobin Post-Translational Modifications Influence Color Stability of Beef Longissimus Lumborum
Post-translational modifications (PTM) of proteins play critical roles in biological processes. PTM of muscle proteins influence meat quality. Nonetheless, myoglobin (Mb) PTM and their impact on fresh beef color stability have not been characterized yet. Therefore, our objectives were to identify Mb PTM in beef longissimus lumborum muscle during postmortem aging and to characterize their influence on color stability. The longissimus lumborum muscles from 9 (n = 9) beef carcasses (24 h postmortem) were subjected to wet aging for 0, 7, 14, and 21 d. At the end of each wet-aging period, steaks were fabricated. One steak for analyses of PTM was immediately frozen at −80°C, whereas other steaks were assigned to refrigerated storage in the darkness under aerobic packaging. Instrumental color and biochemical attributes were evaluated on day 0, 3, or 6 of storage. Mb PTM were analyzed using two-dimensional electrophoresis and tandem mass spectrometry. Surface redness (a* value), color stability, and Mb concentration decreased (P < 0.05) upon aging. Gel image analyses identified 6 Mb spots with similar molecular weight (17 kDa) but different isoelectric pH. Tandem mass spectrometry identified multiple PTM (phosphorylation, methylation, carboxymethylation, acetylation, and 4-hydroxynonenal alkylation) in these 6 isoforms. The amino acids susceptible to phosphorylation were serine (S), threonine (T), and tyrosine, whereas other PTM were detected in lysine (K), arginine (R), and histidine residues. Additionally, distal histidine (position 64), critical to heme stability, was found to be alkylated. Overall, Mb PTM increased with aging. The aging-induced PTM, especially those occurring close to hydrophobic heme pocket, could disrupt Mb tertiary structure, influence heme affinity, and compromise oxygen binding capacity, leading to decreased color stability of fresh beef. Furthermore, PTM at K45, K47, and K87 were unique to Mb from non-aged beef, whereas PTM at R31, T51, K96, K98, S121, R139, and K147 were unique to Mb from aged counterparts, indicating that these Mb PTM could be used as novel biomarkers for fresh beef color stability
Broiler Genetics Influences Proteome Profiles of Normal and Woody Breast Muscle
Wooden or woody breast (WB) is a myopathy of the pectoralis major in fast-growing broilers that influences the quality of breast meat and causes an economic loss in the poultry industry. The objective of this study was to evaluate growth and proteome differences between 5 genetic strains of broilers that yield WB and normal breast (NB) meat. Eight-week-old broilers were evaluated for the WB myopathy and divided into NB and WB groups. Differential expression of proteins was analyzed using 2-dimensional gel electrophoresis and LC-MS/MS to elucidate the mechanism behind the breast myopathy because of the genetic backgrounds of the birds. The percentages of birds with WB were 61.3, 68.8, 46.9, 45.2, and 87.5% for strains 1-5, respectively, indicating variability in WB myopathy among broiler strains. Birds from strains 1, 3, and 5 in the WB group were heavier than those in the NB group (P \u3c 0.05). Woody breast meat from all strains were heavier than NB meat (P \u3c 0.05). Within WB, strain 5 had a greater breast yield than strains 1, 3, and 4 (P \u3c 0.0001). Woody breast from strains 2, 3, 4, and 5 had a greater breast yield than NB (P \u3c 0.05). Six proteins were more abundant in NB of strain 5 than those of strains 2, 3, and 4, and these proteins were related to muscle growth, regeneration, contraction, apoptosis, and oxidative stress. Within WB, 14 proteins were differentially expressed between strain 5 and other strains, suggesting high protein synthesis, weak structural integrity, intense contraction, and oxidative stress in strain 5 birds. The differences between WB from strain 3 and strains 1, 2, and 4 were mainly glycolytic. In conclusion, protein profiles of broiler breast differed because of both broiler genetics and the presence of WB myopathy
Thermal Instability Induced by 4-Hydroxy-2-Nonenal in Beef Myoglobin
The secondary products of lipid oxidation, such as 4-hydroxy-2-nonenal (HNE), compromise myoglobin (Mb) redox stability and can thus impact thermal stability. Previous studies examined HNE-induced redox instability in beef Mb, whereas investigations are yet to be undertaken to evaluate the relationship between lipid oxidation and thermal stability of beef Mb. Therefore, the objective of the present study was to investigate the direct influence of HNE on thermal stability of beef Mb at meat conditions. Beef oxymyoglobin (0.15 mM) was incubated with HNE (1.0 mM) at pH 5.6 and 4°C for 21 d in the dark. Metmyoglobin formation, percentage Mb denaturation (PMD), and HNE adduction sites in Mb were examined on days 0, 7, 14, and 21. The experiment was replicated 3 times (n = 3). The data were evaluated using the MIXED procedure of SAS, and the differences among means were detected at the 5% level using the least significant difference test. The HNE-treated samples exhibited greater (P < 0.05) metmyoglobin formation and PMD than the controls. Additionally, the PMD difference between HNE-treated and control samples increased (P < 0.05) over time. Mass spectrometric analyses indicated that the number of HNE adduction sites increased with storage, and 6 histidines (positions 24, 36, 64, 93, 113, and 152) were adducted on day 21. HNE adduction at the distal histidine (position 64), which is critical to he me stability, was observed only on days 14 and 21. An increase in PMD on days 14 and 21 in HNE-treated samples could be partially due to the adduction at distal histidine. These findings indicated that HNE compromises thermal stability of beef Mb, possibly through altering the conformation of the heme protein by nucleophilic adduction
Improving Performance of All-Polymer Solar Cells Through Backbone Engineering of Both Donors and Acceptors
All-polymer solar cells (APSCs), composed of semiconducting donor and acceptor polymers, have attracted considerable attention due to their unique advantages compared to polymer-fullerene-based devices in terms of enhanced light absorption and morphological stability. To improve the performance of APSCs, the morphology of the active layer must be optimized. By employing a random copolymerization strategy to control the regularity of the backbone of the donor polymers (PTAZ-TPDx) and acceptor polymers (PNDI-Tx) the morphology can be systematically optimized by tuning the polymer packing and crystallinity. To minimize effects of molecular weight, both donor and acceptor polymers have number-average molecular weights in narrow ranges. Experimental and coarse-grained modeling results disclose that systematic backbone engineering greatly affects the polymer crystallinity and ultimately the phase separation and morphology of the all-polymer blends. Decreasing the backbone regularity of either the donor or the acceptor polymer reduces the local crystallinity of the individual phase in blend films, affording reduced short-circuit current densities and fill factors. This two-dimensional crystallinity optimization strategy locates a PCE maximum at highest crystallinity for both donor and acceptor polymers. Overall, this study demonstrates that proper control of both donor and acceptor polymer crystallinity simultaneously is essential to optimize APSC performance
Supranutritional Supplementation of Vitamin E Influences Myoglobin Post-Translational Modifications in Postmortem Beef Longissimus Lumborum Muscle
Post-translational modifications (PTM) in myoglobin (Mb) can influence fresh meat color stability. Dietary supplementation of vitamin E improves beef color stability by delaying lipid oxidation–induced Mb oxidation and influences proteome profile of postmortem beef skeletal muscles. Nonetheless, the influence of vitamin E on Mb PTM in postmortem beef skeletal muscles has yet to be investigated. Therefore, the objective of the current study was to examine the effect of dietary vitamin E on Mb PTM in postmortem beef longissimus lumborum muscle. Beef longissimus lumborum muscle samples (24 h postmortem) were obtained from the carcasses of 9 vitamin E–supplemented (VITE; 1,000 IU vitamin E diet/heifer·d−1for 89 d) and 9 control (CONT; no supplemental vitamin E) heifers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to separate Mb from other sarcoplasmic proteins of beef longissimus lumborum muscle. Tandem mass spectrometry identified multiple PTM (phosphorylation, acetylation, 4-hydroxynonenalalkylation, methylation, dimethylation, trimethylation, and carboxymethylation) in the protein bands (17 kDa) representing Mb. The amino acids susceptible to phosphorylation were threonine (T) and tyrosine (Y), whereas lysine (K) residues were prone to other PTM. The same sites of phosphorylation (T34, T67, Y103), carboxymethylation (K77, K78), and 4-hydroxynonenal alkylation (K77, K78, K79) were identified in Mb from CONT and VITE samples, indicating that these PTM were not influenced by the vitamin E supplementation in cattle. Nonetheless, differential occurrence of acetylation, methylation, dimethylation, and trimethylation were identified in Mb from CONT and VITE samples. Overall, a greater number of amino acids were modified in CONT than VITE, suggesting that the supplementation of vitamin E decreased thenumbers of post-translationally modified residues in Mb. Additionally, PTM at K87, K96, K98, and K102 were unique to CONT, whereas PTM at K118 were unique to VITE. These findings suggested that dietary supplementation of vitamin E in beef cattle might protect amino acid residues in Mb—especially those located spatially close to proximal histidine—from undergoing PTM, thereby improving Mb redox stability
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