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1.
Appl Opt ; 63(12): 3108-3116, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38856454

RESUMO

In general, visible light communication (VLC) uses LEDs as transmitters. However, LEDs can serve as receivers to construct a simple duplex VLC system that uses only two LEDs instead of one LED and one photo-diode (PD). There is a lack of effective equivalent analysis models for characterizing and evaluating the inherent behavioral characteristics of LEDs used as receivers. This paper presents an equivalent analysis model for GaN LEDs as receivers. First, based on the proposed receiving equivalent circuit model, a third-order signal transmission mathematical analysis model is established, revealing the transmission relationship between the photocurrent and output voltage. Further research is conducted on the impact of parameter changes on the bandwidth, and the model can be simplified into a first-order low-pass mathematical analysis model under specific conditions, providing theoretical support for improving the bandwidth of LED receiving applications. The experimental results also confirm the theoretical predictions. This research result holds significant importance for revealing the intrinsic mechanisms and the improved optical communication performance of LEDs for effective reception.

2.
Opt Express ; 31(21): 34748-34763, 2023 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37859224

RESUMO

In the current visible light communication (VLC) system, a condenser lens is generally used in the front of receiver to achieve a higher data rate, making an extremely narrow field-of-view for the receiver. With the spread of Industrial Internet of Things (IIoT), the communication between mobile terminals is urgently required. A wide-range detecting method for VLC system in IIoT scenario is asked. In this paper, a novel self-adaptive wide-FoV receiver involving reconfigurable intelligent surfaces (RIS) is proposed. The effective detecting range of the receiver can be expanded by dynamically adjusting the incident light directions with the assistance of RIS. Based on the maximum arrived flux criterion, the mathematical model is established and the optimized RIS parameter tuning algorithm is presented. The feasibility and validity of the method are verified by simulation. The results show that the tolerable transceiver offset can be increased to 2∼4 times as the conventional receiver.

3.
Appl Opt ; 61(36): 10688-10693, 2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36606927

RESUMO

Recently, visible light communication (VLC) has become a promising technology for reliable communication in the industrial Internet of Things. In VLC, light sources with non-uniform parameters make uncontrollable signal blind zones and aliases. The unknown parameters also lead to the problem of channel estimation. Hence, deep coverage of VLC is challenging. In this paper, we design a dual-sensor elongated receiver. The receiver expands the signal receiving area by increasing the distance between photon detectors and realizes aliased signal recovery without channel estimation. Cooperatively, an adaptive blind receiving scheme is proposed. The scheme separates aliased signals by parameter estimation of a Gaussian mixture model without knowing transmitter parameters. It unifies the aliased and blind receiving cases by an adaptive signal combining method. Finally, the simulation results demonstrate that our scheme achieves better reliability and deeper communication coverage in the given system.

4.
BMC Psychiatry ; 20(1): 490, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33023555

RESUMO

BACKGROUND: A number of studies have explored the association between depression and ghrelin, leptin, and cortisol; further, postprandial C-peptide levels have a therapeutic effect on type 2 diabetes mellitus (T2DM). However, the relationship between C-peptide and depression in patients with diabetes, remains unclear. The aim of this study was to explore the association between depression and ghrelin, leptin, cortisol, and C-peptide in patients with diabetes. METHODS: We enrolled 50 adults without T2DM, 77 non-depressed adults with T2DM (free of Axis-I psychiatric disorders as assessed using the Mental Illness Needs Index (MINI), Patient Health Questionnaire (PHQ-9 score ≤ 4)) and 59 patients with T2DM and depression (PHQ-9 ≥ 7 and positive by the Structured Clinical Interview for DSM-5). The age range of the participants was 45-59 years of age. We compared the above three groups and explored the association between ghrelin, leptin, cortisol, C-peptide, and depression in patients with diabetes. A post-hoc power-analysis was finished. RESULTS: Compared with the non-depression T2DM group, the depression T2DM group had significantly higher blood glucose fluctuations. Further, compared with the non-depression T2DM and non-diabetic groups, the depression T2DM group had significantly lower levels of post-meal 2-h C-peptide and elevated evening cortisol (p < 0.01). Regression analysis revealed a significant negative correlation between depression severity and 2-h postprandial C-peptide in patients with diabetes (p < 0.01) and a significant positive correlation with midnight cortisol levels (p < 0.01). A post hoc power analysis showed that we had an adequate sample size and met the minimum requirement to attain 80% power. A post hoc power calculation also demonstrated that this study basically achieved power of 80% at 5% alpha level. CONCLUSIONS: Our findings indicate a correlation of low fasting levels of 2-h C-peptide as well as higher midnight cortisol levels with higher depression severity in middle-aged patients with T2DM.


Assuntos
Diabetes Mellitus Tipo 2 , Hidrocortisona , Adulto , Idoso , Glicemia , Peptídeo C , Depressão/complicações , Diabetes Mellitus Tipo 2/complicações , Grelina , Humanos , Pessoa de Meia-Idade
5.
Appl Opt ; 58(36): 9786-9796, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31873621

RESUMO

Massive multi-color visible light communications (mMC-VLC) sufficiently utilizing space and color domain resources is proposed to satisfy high-spectral-efficiency, high-speed, and high-density-coverage requirements of next-generation indoor data connections. However, the gap between the number of LEDs and photodiodes (PDs) and the high correlation among different channels limit the multiplexing of mMC-VLC. Also, the mobility of the receiver is the bottleneck of mMC-VLC. So, adaptive spatial-layout selection (ASLS) is proposed to settle the above problems, which selects $ N $N sets $ n $n-color LEDs from the transmitter to form an approximate optimal closed-circle layout adapting to the receiver position. First, the optimal parameter problems to minimize the ill condition of the activated system under layout constraints of the closed circle and linear types are formulated for a fixed receiver position. Second, to achieve adaptivity, the fitting curves of the optimal layout parameter and $ {D_v} $Dv under both constraints are researched; $ {D_v} $Dv is the vertical distance between the transmitter and receiver planes. Finally, the closest layout-selected principle (CLSP) is proposed to solve the problem of the LEDs perhaps not perfectly forming the optimal parameter layout for mMC-VLC. The bit-error ratio (BER) performances and application scopes of ASLS under both layout constraints are compared to determine that the constraint layout is a closed circle; meanwhile the available maximal $ N $N corresponding to the receiver position is obtained. The optimal parameter of ASLS is linearly related to the receiver position and not related to $ N $N. The ASLS always achieves better BER performance than optical multi-stream spatial modulation.

6.
Appl Opt ; 58(6): 1433-1441, 2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30874028

RESUMO

A fast-adaptive color-collaborative signal constellation (CCSC) is proposed for chromaticity-changeable multicolor multiple-input multiple-output (MIMO) visible light communications (VLC) systems. The design of CCSC aims at developing the constellation to minimize the average optical power with shaping-based lattice code. For multicolor VLC signals, we arrive at the fact that the optimum shape of the constellation bounding region is an inequilateral N-D simplex. With the densest lattice-packing structure, detailed design steps of CCSC are fully elaborated by lattice construction, effective point selection, and chromaticity adjustment. As CCSC has a low complexity, its constellation structure can adapt quickly to changeable chromaticity demands. Simulation results show that the performance of CCSC is better than enhanced standard color shift keying (CSK) and is close to iterative CSK modulation based on numerical search.

7.
Appl Opt ; 57(20): 5852-5858, 2018 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-30118057

RESUMO

For the long distance single photon avalanche diode (SPAD)-based underwater visible light communication (UVLC) system, the multiple-symbol union detection scheme is presented. However, an error floor curve of the bit-to-error ratio (BER) occurs and cannot vanish even though the transmitted power approaches infinity. In this paper, to solve the problems of error floor and channel estimation in the long distance SPAD-based UVLC system, we propose the one training symbol maximum likelihood (ML) detection receiver. First, we add one training symbol in the head of each frame to eliminate the error floor and ensure the reliable blind estimation of the long distance UVLC channel. Meanwhile, the training ML detection (TMLD) receiver is developed. And then, to improve the system performance, a training modified (TM) quasi-ML receiver with Anscombe root transformation is proposed. Compared to the traditional mean detection scheme of the SPAD receiver, the simulation results show that the proposed TM quasi-ML and TMLD schemes significantly improve the error-rate performance.

8.
Immunol Invest ; 46(3): 305-313, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28332870

RESUMO

Studies demonstrated that deficiency in 17ß-estradiol (E2) in postmenopausal women influences their immune system. However, few studies have reported alterations in immunologic presentation during nonnatural menopause in young females. Here we compared the differences in immune response between young C57BL/6N mice with surgical or medical variectomy and aged C57BL/6N mice with the common feature of E2 deficiency following Con A stimulation. We observed inverted CD4/CD8 ratios in the aged group and apparent reduced production of serum immunoglobin (Ig)G, IgA, and IgM in the surgical group, whereas changes in immune parameters in the medical group were moderate. These data suggested that the immunological response to Con A stimulus differed among the three groups and that E2 deficiency was only partially responsible for the development of immune deficiency in aged mice.


Assuntos
Envelhecimento/fisiologia , Estradiol/deficiência , Menopausa Precoce/imunologia , Pós-Menopausa/fisiologia , Linfócitos T/imunologia , Animais , Relação CD4-CD8 , Concanavalina A/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Ovariectomia
9.
Appl Opt ; 56(32): 8959-8968, 2017 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-29131183

RESUMO

In this paper, we investigate visible light communication (VLC) attocell systems in which any two neighboring attocells overlap. An efficient signal design for VLC called time superposition reuse (TSR) is proposed to mitigate interference and improve spectral efficiency. In the scheme, two neighboring cells are allocated with two time slots that have superposition in the time domain. By adjusting superposition between time slots, the system can achieve a flexible spectral efficiency and system performance. Further, we develop an optimal power allocation strategy for TSR in the system. The strategy is given according to the position of the user and the level of superposition, and then the corresponding optimal Euclidean distance is derived. In addition, we analyze the system performance and prove that the optimal Euclidean distance is an increasing function of the delay between signals and a decreasing function of the sampling period. Simulation results demonstrate that the optimal power allocation has a better performance than uniform power allocation and TSR outperforms time division multiple access significantly for the user in VLC attocell systems.

10.
J Cell Mol Med ; 20(3): 526-36, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26805397

RESUMO

Gastric cancer is one of the most common malignancies worldwide. Interleukin-1-beta (IL-1ß) is a pro-inflammatory cytokine and potent inhibitor of gastric acid secretion. Some studies provided evidence of the association between IL-1B 31 polymorphism and gastric cancer risk while other studies did not. Therefore, we conducted a comprehensive meta-analysis to reassess the association. A systematic literature search of the PubMed and EMBASE databases identified 37 studies with 6108 cases and 8980 controls for this meta-analysis. The crude odd ratios (ORs) and the 95% confidence intervals (CIs) were calculated to evaluate the strength of the association. Meta-regression was used to determine the major source of heterogeneity across the studies. The pooled analysis did not suggest the significant association of IL-1B 31 C>T polymorphism with gastric cancer risk. Stratified analysis was performed by ethnicity, source of control, genotype method, and indicated a significantly increased gastric cancer risk associated with IL-1B 31T variant in the population-based subgroup (heterozygous model: OR = 1.22, 95% CI = 1.03-1.45). Moreover, stratified analysis by Helicobacter pylori infection status indicated that IL-1B 31 polymorphism increased gastric cancer risk in infection-positive subgroup (homozygous model: OR = 1.35, 95% CI = 1.02-1.78; heterozygous model: OR = 1.31, 95% CI = 1.04-1.66; recessive model: OR = 1.29, 95% CI = 1.04-1.61). The study suggested that IL-1B 31 polymorphism might confer susceptibility to gastric cancer in the presence of H. pylori infection, indicating a gene-environment interaction in gastric carcinogenesis.


Assuntos
Infecções por Helicobacter/genética , Helicobacter pylori/fisiologia , Interleucina-1beta/genética , Neoplasias Gástricas/genética , Estudos de Casos e Controles , Interação Gene-Ambiente , Estudos de Associação Genética , Predisposição Genética para Doença , Infecções por Helicobacter/microbiologia , Humanos , Polimorfismo de Nucleotídeo Único , Neoplasias Gástricas/microbiologia
11.
Am J Pathol ; 185(5): 1396-408, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25773177

RESUMO

Obesity poses an increased risk of developing metabolic syndrome and closely associated nonalcoholic fatty liver disease, including liver cancer. Satiety hormone leptin-deficient (ob/ob) mice, considered paradigmatic of nutritional obesity, develop hepatic steatosis but are less prone to developing liver tumors. Sustained activation of peroxisome proliferator-activated receptor α (PPARα) in ob/ob mouse liver increases fatty acid oxidation (FAO), which contributes to attenuation of obesity but enhances liver cancer risk. To further evaluate the role of PPARα-regulated hepatic FAO and energy burning in the progression of fatty liver disease, we generated PPARα-deficient ob/ob (PPARα(Δ)ob/ob) mice. These mice become strikingly more obese compared to ob/ob littermates, with increased white and brown adipose tissue content and severe hepatic steatosis. Hepatic steatosis becomes more severe in fasted PPARα(Δ)ob/ob mice as they fail to up-regulate FAO systems. PPARα(Δ)ob/ob mice also do not respond to peroxisome proliferative and mitogenic effects of PPARα agonist Wy-14,643. Although PPARα(Δ)ob/ob mice are severely obese, there was no significant increase in liver tumor incidence, even when maintained on a diet containing Wy-14,643. We conclude that sustained PPARα activation-related increase in FAO in fatty livers of obese ob/ob mice increases liver cancer risk, whereas deletion of PPARα in ob/ob mice aggravates obesity and hepatic steatosis. However, it does not lead to liver tumor development because of reduction in FAO and energy burning.


Assuntos
Ácidos Graxos/metabolismo , Neoplasias Hepáticas/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/metabolismo , PPAR alfa/deficiência , Animais , Modelos Animais de Doenças , Immunoblotting , Neoplasias Hepáticas/etiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Hepatopatia Gordurosa não Alcoólica/etiologia , Obesidade/complicações , Oxirredução , Reação em Cadeia da Polimerase em Tempo Real
12.
Opt Express ; 24(8): 7905-14, 2016 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-27137232

RESUMO

In this paper, we consider the design of space code for an intensity modulated direct detection multi-input-multi-output optical wireless communication (IM/DD MIMO-OWC) system, in which channel coefficients are independent and non-identically log-normal distributed, with variances and means known at the transmitter and channel state information available at the receiver. Utilizing the existing space code design criterion for IM/DD MIMO-OWC with a maximum likelihood (ML) detector, we design a diversity-optimal space code (DOSC) that maximizes both large-scale diversity and small-scale diversity gains and prove that the spatial repetition code (RC) with a diversity-optimized power allocation is diversity-optimal among all the high dimensional nonnegative space code schemes under a commonly used optical power constraint. In addition, we show that one of significant advantages of the DOSC is to allow low-complexity ML detection. Simulation results indicate that in high signal-to-noise ratio (SNR) regimes, our proposed DOSC significantly outperforms RC, which is the best space code currently available for such system.

13.
Opt Lett ; 41(2): 329-32, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26766706

RESUMO

We consider an indoor multi-input single-output (MISO) visible light communication (VLC) system without channel state information at the transmitter. For such a system, an energy-efficient time-collaborative modulation (TCM) constellation is first designed by minimizing a total optical power subject to a fixed minimum Euclidean distance. Then, a new space-time transmission scheme is proposed. Comprehensive computer simulations indicate that our proposed design always has better average error performance within illumination coverage area than the currently available schemes for this application.

14.
J Biol Chem ; 289(45): 31373-81, 2014 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-25258321

RESUMO

ASH2L is a component of MLL complexes that confer H3K4 trimethylation. The ASH2L gene is located at 8q11-12, which is often amplified in breast cancers. We found that increased ASH2L expression, which can result from gene amplification, is often correlated with increased ERα expression in both breast cancer cell lines and primary breast cancers. Forced expression of ASH2L induced ERα expression in mammary epithelial cells, whereas depletion of ASH2L suppressed ERα expression in breast cancer cells. To understand the mechanism by which ASH2L regulates ERα expression, we identified GATA3 as the binding protein of ASH2L. ASH2L was shown to potentiate the transcriptional activity of GATA3. ASH2L was recruited to the enhancer of the ERα gene through GATA3 to promote ERα transcription. This study established that ASH2L enhances ERα expression as a coactivator of GATA3 in breast cancers.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Receptor alfa de Estrogênio/metabolismo , Fator de Transcrição GATA3/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas Nucleares/fisiologia , Fatores de Transcrição/fisiologia , Animais , Sítios de Ligação , Neoplasias da Mama/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/genética , Elementos Facilitadores Genéticos , Receptor alfa de Estrogênio/genética , Feminino , Regulação da Expressão Gênica , Células HEK293 , Histonas/metabolismo , Humanos , Camundongos , Proteínas Nucleares/genética , Transdução de Sinais , Fatores de Transcrição/genética , Transcrição Gênica , Técnicas do Sistema de Duplo-Híbrido
15.
J Biol Chem ; 288(39): 27898-911, 2013 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-23943624

RESUMO

Mediator, a large multisubunit protein complex, plays a pivotal role in gene transcription by linking gene-specific transcription factors with the preinitiation complex and RNA polymerase II. In the liver, the key subunit of the Mediator complex, Med1, interacts with several nuclear receptors and transcription factors to direct gene-specific transcription. Conditional knock-out of Med1 in the liver showed that hepatocytes lacking Med1 did not regenerate following either partial hepatectomy or treatment with certain nuclear receptor activators and failed to give rise to tumors when challenged with carcinogens. We now report that the adenovirally driven overexpression of Med1 in mouse liver stimulates hepatocyte DNA synthesis with enhanced expression of DNA replication, cell cycle control, and liver-specific genes, indicating that Med1 alone is necessary and sufficient for liver cell proliferation. Importantly, we demonstrate that AMP-activated protein kinase (AMPK), an important cellular energy sensor, interacts with, and directly phosphorylates, Med1 in vitro at serine 656, serine 756, and serine 796. AMPK also phosphorylates Med1 in vivo in mouse liver and in cultured primary hepatocytes and HEK293 and HeLa cells. In addition, we demonstrate that PPARα activators increase AMPK-mediated Med1 phosphorylation in vivo. Inhibition of AMPK by compound C decreased hepatocyte proliferation induced by Med1 and also by the PPARα activators fenofibrate and Wy-14,643. Co-treatment with compound C attenuated PPARα activator-inducible fatty acid ß-oxidation in liver. Our results suggest that Med1 phosphorylation by its association with AMPK regulates liver cell proliferation and fatty acid oxidation, most likely as a downstream effector of PPARα and AMPK.


Assuntos
Adenilato Quinase/metabolismo , Regulação Enzimológica da Expressão Gênica , Fígado/citologia , Subunidade 1 do Complexo Mediador/metabolismo , Complexo Mediador/metabolismo , Animais , Proliferação de Células , Ácidos Graxos/metabolismo , Células HEK293 , Células HeLa , Hepatócitos/citologia , Homeostase , Humanos , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oxigênio/metabolismo , PPAR alfa/metabolismo , Fosforilação
16.
Elife ; 122024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38470230

RESUMO

In the process of synaptic formation, neurons must not only adhere to specific principles when selecting synaptic partners but also possess mechanisms to avoid undesirable connections. Yet, the strategies employed to prevent unwarranted associations have remained largely unknown. In our study, we have identified the pivotal role of combinatorial clustered protocadherin gamma (γ-PCDH) expression in orchestrating synaptic connectivity in the mouse neocortex. Through 5' end single-cell sequencing, we unveiled the intricate combinatorial expression patterns of γ-PCDH variable isoforms within neocortical neurons. Furthermore, our whole-cell patch-clamp recordings demonstrated that as the similarity in this combinatorial pattern among neurons increased, their synaptic connectivity decreased. Our findings elucidate a sophisticated molecular mechanism governing the construction of neural networks in the mouse neocortex.


Assuntos
Proteínas Relacionadas a Caderinas , Neocórtex , Animais , Camundongos , Caderinas/genética , Redes Neurais de Computação
17.
Indian J Med Microbiol ; 42: 85-88, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36400645

RESUMO

Solobacterium moorei is an asporogenous, strictly anaerobic, short-to-long bacillus belonging to the family Erysipelotrichidae and phylum Firmicutes. This bacterium rarely causes bloodstream infections. Here, we report a case of the postoperative recurrence and metastasis of gastric antral adenocarcinoma combined with S. moorei bloodstream infection.


Assuntos
Bacteriemia , Sepse , Humanos , Bacteriemia/diagnóstico , Bacteriemia/microbiologia , RNA Ribossômico 16S , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
18.
Polymers (Basel) ; 14(15)2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35893981

RESUMO

Based on the experience of the foundry industry, reducing the demolding time is the key for mass production of wax patterns with sophisticated geometries. Integration of numerical simulation and rapid tooling technology for decreasing the time to market is essential in advanced manufacturing technology. However, characterization of epoxy-based rapid molds with a profiled conformal cooling channel (PCCC) using computer-aided engineering simulation of the epoxy-based rapid mold with PCCC was not found in the literature. In this study, epoxy-based rapid molds with PCCC were characterized numerically and experimentally. The cooling performance of wax injection molds with two different kinds of cross-sections of the cooling channel was investigated. Four pairs of injection molds with PCCC were implemented using four different kinds of material formulations. It was found that the cooling performance of the PCCC was better than a circular conformal cooling channel (CCCC) since the PCCC maintained a more uniform and steady cooling performance of injection-molded product than CCCC. Epoxy resin added with 41 vol.% Cu powder seems to be a cost-effective empirical material formulation in terms of cooling time and material costs. This empirical material formulation provided an injection mold with low material cost and good cooling performance simultaneously compared to an injection mold fabricated with commercial material. The cooling performance could reach 88% of that of the injection mold fabricated with commercial material. The material cost of making the injection mold was only about 60% of that of the injection mold fabricated with commercial material. The coolant flow rate had no significant effect on the cooling time, whereas the cooling time of the wax pattern was affected by coolant temperature significantly.

19.
Curr Biol ; 32(14): 3137-3145.e3, 2022 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-35659861

RESUMO

Dissecting neural connectivity patterns within local brain regions is an essential step to understanding the function of the brain.1 Neural microcircuits in brain regions, such as the neocortex and the hippocampus, have been extensively studied.2 By contrast, the microcircuit in the hypothalamus remains largely uncharacterized. The hypothalamus is crucial for animals' survival and reproduction.3 Knowledge of how different hypothalamic nuclei coordinate with each other and outside brain regions for hypothalamus-related functions has been significantly advanced.4-9 Although there are limited studies on the neural microcircuit in the lateral hypothalamus (LHA)10,11 and the suprachiasmatic nucleus (SCN),12,13 the patterns of neural microcircuits in most of the given hypothalamic nuclei remain largely unknown. This study applied combinatory approaches to address the local neural circuit pattern in the ventromedial hypothalamus (VMH) and other hypothalamic nuclei. We discovered a unique neural circuit design in the VMH. Neurons in the VMH were electrically coupled at the early postnatal stage like ones in the neocortex.14 However, unlike neocortical neurons,14,15 they developed very few chemical synapses after the disappearance of electrical synapses. Instead, VMH neurons communicated with neuropeptides. The similar scarceness of synaptic connectivity found in other hypothalamic nuclei further indicated that the lack of synaptic connections is a unique feature for local neural circuits in most adult hypothalamic nuclei. Thus, our findings provide a solid synaptic basis at the cellular level to understand hypothalamic functions better.


Assuntos
Hipotálamo , Neuropeptídeos , Animais , Comunicação Celular , Região Hipotalâmica Lateral/fisiologia , Hipotálamo/fisiologia , Neurônios/fisiologia , Núcleo Hipotalâmico Ventromedial/fisiologia
20.
Polymers (Basel) ; 14(2)2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-35054687

RESUMO

Metal additive manufacturing techniques are frequently applied to the manufacturing of injection molds with a conformal cooling channel (CCC) in order to shorten the cooling time in the injection molding process. Reducing the cooling time in the cooling stage is essential to reducing the energy consumption in mass production. However, the distinct disadvantages include higher manufacturing costs and longer processing time in the fabrication of injection mold with CCC. Rapid tooling technology (RTT) is a widely utilized technology to shorten mold development time in the mold industry. In principle, the cooling time of injection molded products is affected by both injection mold material and coolant medium. However, little work has been carried out to investigate the effects of different mold materials and coolant media on the cooling performance of epoxy-based injection molds quantitatively. In this study, the effects of four different coolant media on the cooling performance of ten sets of injection molds fabricated with different mixtures were investigated experimentally. It was found that cooling water with ultrafine bubble is the best cooling medium based on the cooling efficiency of the injection molded parts (since the cooling efficiency is increased further by about 12.4% compared to the conventional cooling water). Mold material has a greater influence on the cooling efficiency than the cooling medium, since cooling time range of different mold materials is 99 s while the cooling time range for different cooling media is 92 s. Based on the total production cost of injection mold and cooling efficiency, the epoxy resin filled with 41 vol.% aluminum powder is the optimal formula for making an injection mold since saving in the total production cost about 24% is obtained compared to injection mold made with commercially available materials.

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