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1.
Nature ; 582(7810): 89-94, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32483373

RESUMO

A hexanucleotide-repeat expansion in C9ORF72 is the most common genetic variant that contributes to amyotrophic lateral sclerosis and frontotemporal dementia1,2. The C9ORF72 mutation acts through gain- and loss-of-function mechanisms to induce pathways that are implicated in neural degeneration3-9. The expansion is transcribed into a long repetitive RNA, which negatively sequesters RNA-binding proteins5 before its non-canonical translation into neural-toxic dipeptide proteins3,4. The failure of RNA polymerase to read through the mutation also reduces the abundance of the endogenous C9ORF72 gene product, which functions in endolysosomal pathways and suppresses systemic and neural inflammation6-9. Notably, the effects of the repeat expansion act with incomplete penetrance in families with a high prevalence of amyotrophic lateral sclerosis or frontotemporal dementia, indicating that either genetic or environmental factors modify the risk of disease for each individual. Identifying disease modifiers is of considerable translational interest, as it could suggest strategies to diminish the risk of developing amyotrophic lateral sclerosis or frontotemporal dementia, or to slow progression. Here we report that an environment with reduced abundance of immune-stimulating bacteria10,11 protects C9orf72-mutant mice from premature mortality and significantly ameliorates their underlying systemic inflammation and autoimmunity. Consistent with C9orf72 functioning to prevent microbiota from inducing a pathological inflammatory response, we found that reducing the microbial burden in mutant mice with broad spectrum antibiotics-as well as transplanting gut microflora from a protective environment-attenuated inflammatory phenotypes, even after their onset. Our studies provide further evidence that the microbial composition of our gut has an important role in brain health and can interact in surprising ways with well-known genetic risk factors for disorders of the nervous system.


Assuntos
Proteína C9orf72/genética , Microbioma Gastrointestinal/fisiologia , Gliose/microbiologia , Gliose/patologia , Inflamação/genética , Inflamação/microbiologia , Medula Espinal/patologia , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Antibacterianos/farmacologia , Autoimunidade/efeitos dos fármacos , Autoimunidade/genética , Autoimunidade/imunologia , Movimento Celular/efeitos dos fármacos , Citocinas/imunologia , Transplante de Microbiota Fecal , Feminino , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/imunologia , Gliose/genética , Gliose/prevenção & controle , Inflamação/patologia , Inflamação/prevenção & controle , Mutação com Perda de Função/genética , Masculino , Camundongos , Microglia/imunologia , Microglia/microbiologia , Microglia/patologia , Medula Espinal/imunologia , Medula Espinal/microbiologia , Taxa de Sobrevida
2.
Genes Dev ; 32(13-14): 929-943, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29950492

RESUMO

While a mutation in C9ORF72 is the most common genetic contributor to amyotrophic lateral sclerosis (ALS), much remains to be learned concerning the function of the protein normally encoded at this locus. To elaborate further on functions for C9ORF72, we used quantitative mass spectrometry-based proteomics to identify interacting proteins in motor neurons and found that its long isoform complexes with and stabilizes SMCR8, which further enables interaction with WDR41. To study the organismal and cellular functions for this tripartite complex, we generated Smcr8 loss-of-function mutant mice and found that they developed phenotypes also observed in C9orf72 loss-of-function animals, including autoimmunity. Along with a loss of tolerance for many nervous system autoantigens, we found increased lysosomal exocytosis in Smcr8 mutant macrophages. In addition to elevated surface Lamp1 (lysosome-associated membrane protein 1) expression, we also observed enhanced secretion of lysosomal components-phenotypes that we subsequently observed in C9orf72 loss-of-function macrophages. Overall, our findings demonstrate that C9ORF72 and SMCR8 have interdependent functions in suppressing autoimmunity as well as negatively regulating lysosomal exocytosis-processes of potential importance to ALS.


Assuntos
Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/fisiopatologia , Autoimunidade/genética , Proteínas de Transporte/metabolismo , Exocitose/genética , Lisossomos/metabolismo , Animais , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Proteínas de Transporte/genética , Regulação da Expressão Gênica/genética , Humanos , Linfonodos/patologia , Proteína 1 de Membrana Associada ao Lisossomo/genética , Macrófagos/patologia , Camundongos , Camundongos Knockout , Mutação , Isoformas de Proteínas , Estabilidade Proteica , Esplenomegalia/genética
3.
Anal Chem ; 96(14): 5694-5701, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38538547

RESUMO

Immunochromatography is a commonly used immediate detection technique, using signal labels to generate detection signals for rapid medical diagnosis. However, its detection sensitivity is affected by background fluorescence caused by the excitation light source. We have developed an immunochromatographic test strip using Zn2GeO4:Mn2+ (ZGM) persistent luminescent nanoparticles (PLNPs) for immediate fluorescence detection and highly sensitive persistent luminescence (PersL) detection without background fluorescence interference. ZGM emits a strong green light when exposed to ultraviolet (UV) excitation, and its green PersL can persist for over 30 min after the excitation light is turned off. We modified the surface of ZGM with heparin-binding protein (HBP) antibodies to create immunochromatographic test strips for the detection of HBP as the target analyte. Under UV excitation, the chromatography test paper can be visually observed at concentrations as low as 25 ng/mL. After the excitation light source is switched off, PersL can achieve a detection limit of 4.7 ng/mL without background interference. This dual-mode immunochromatographic detection, based on ZGM, shows great potential for in vitro diagnostic applications.


Assuntos
Germânio , Luminescência , Nanopartículas , Nanopartículas/química , Óxidos , Cromatografia de Afinidade/métodos
4.
Arch Gynecol Obstet ; 309(4): 1151-1163, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37957365

RESUMO

PURPOSE: The aim of this meta-analysis was comparing the efficacy of GnRH antagonist (GnRH-ant) protocol and progestin-primed ovarian stimulation (PPOS) in polycystic ovarian syndrome (PCOS) women. METHODS: A search was conducted from PubMed, Embase, The Cochrane library, Web of Science, and Scopus databases to collect clinical papers regarding GnRH-ant protocol and PPOS protocol from inception to September 2023. Subsequently, the retrieved documents were screened, and the content of the documents that conformed to the requirements was extracted. Moreover, statistical meta-analyses were conducted using the RevMan 5.4 software. Furthermore, with the use of a star-based system and the Cochrane handbook, the methodological quality of the covered papers was evaluated on the Ottawa-Newcastle scale. RESULTS: A total of eight papers were covered in the meta-analysis, with 2156 PCOS women enrolled (i.e., 1085 patients in the GnRH-ant protocol group and 1071 patients in the PPOS group). As indicated by the meta-analysis results, the PPOS group was correlated with a lower risk of ovarian hyperstimulation syndrome (OHSS) (SMD = 9.24, [95% CI: (2.50, 34.21)], P = 0.0009), more gonadotropin (Gn) dose (SMD = - 0.34, [95% CI: (- 0.56, - 0.13)], P = 0.002) compared with GnRH-ant group. No statistical difference was identified on the oocytes condition and pregnancy outcomes. CONCLUSIONS: As revealed by the data of this study, the progesterone protocol is comparable with the GnRH-ant protocol in oocytes condition and clinical outcomes. The progestin-primed ovarian stimulation could serve as an alternative for polycystic ovarian syndrome women who have failed in GnRH antagonist protocol. The above-described conclusions should be verified by more high-quality papers due to the limitation of the number and quality of included papers. TRIAL REGISTRATION: PROSPERO registration: CRD42023411284.


Assuntos
Síndrome do Ovário Policístico , Progestinas , Gravidez , Humanos , Feminino , Progestinas/farmacologia , Progestinas/uso terapêutico , Síndrome do Ovário Policístico/tratamento farmacológico , Fertilização in vitro/métodos , Hormônio Liberador de Gonadotropina , Indução da Ovulação/métodos , Esteroides , Antagonistas de Hormônios/uso terapêutico , Metanálise como Assunto , Revisões Sistemáticas como Assunto
5.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 41(3): 312-316, 2024 Mar 10.
Artigo em Zh | MEDLINE | ID: mdl-38448020

RESUMO

OBJECTIVE: To analyze the clinical phenotype and genetic characteristics of a Chinese pedigree affected with Hereditary antithrombin deficiency. METHODS: A pedigree diagnosed at the the Second Affiliated Hospital of Wenzhou Medical University, Yuying Children's Hospital in June, 2020 was selected as the study subject. Plasma prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), and thrombin time (TT) of the probands and their pedigree members were determined using a STA-R automatic coagulation analyzer. Antithrombin activity (AT: A) and antithrombin antigen (AT: Ag) in plasma were determined with chromogenic substrate and immunonephelometry assays. All exons and flanking sequences of the anticoagulant protein gene SERPINC1 were amplified by PCR and subjected to Sanger sequencing. Candidate variants were verified with bioinformatic tools (PolyPhen-2, SIFT, Mutation Taster and PYMOL) to explore their effect on the function and structural conformation of the protein. RESULTS: The probands (II-2, II-10), their brother (II-5) and sons (III-1, III-8) had shown normal PT, APTT, FIB, and TT, but significantly decreased AT: A and AT: Ag, with their levels being 34%, 57%, 56%, 48%, 53% and 13.51 mg/dL, 13.44 mg/dL, 18.39 mg/dL, 17.36 mg/dL, 17.71 mg/dL, respectively. The remaining pedigree members had normal values. Sanger sequencing revealed that the probands and all affected pedigree members had harbored a heterozygous c.851T>C (p.Met284Thr) missense variant in exon 5 of the SERPINC1 gene. Bioinformatic analysis and simulation suggested that the variant has resulted in alteration of hydrogen bonds at the c.851 position, which may affect the structure of the protein. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PS1+PM1+PM5+PP1+PP4). CONCLUSION: The probands and other affected members were all diagnosed with type I hereditary AT deficiency, for which the c.851T>C (p.Met284Thr) variant of the SERPINC1 gene may be accountable.


Assuntos
Deficiência de Antitrombina III , Masculino , Criança , Humanos , Deficiência de Antitrombina III/genética , Linhagem , Éxons , Fibrinogênio , Anticoagulantes , Antitrombinas , China , Antitrombina III/genética
6.
Virol J ; 20(1): 264, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37968757

RESUMO

The porcine pseudorabies virus (PRV) is one of the most devastating pathogens and brings great economic losses to the swine industry worldwide. Viruses are intracellular parasites that have evolved numerous strategies to subvert and utilize different host processes for their life cycle. Among the different systems of the host cell, the cytoskeleton is one of the most important which not only facilitate viral invasion and spread into neighboring cells, but also help viruses to evade the host immune system. RhoA is a key regulator of cytoskeleton system that may participate in virus infection. In this study, we characterized the function of RhoA in the PRV replication by chemical drugs treatment, gene knockdown and gene over-expression strategy. Inhibition of RhoA by specific inhibitor and gene knockdown promoted PRV proliferation. On the contrary, overexpression of RhoA or activation of RhoA by chemical drug inhibited PRV infection. Besides, our data demonstrated that PRV infection induced the disruption of actin stress fiber, which was consistent with previous report. In turn, the actin specific inhibitor cytochalasin D markedly disrupted the normal fibrous structure of intracellular actin cytoskeleton and decreased the PRV replication, suggesting that actin cytoskeleton polymerization contributed to PRV replication in vitro. In summary, our data displayed that RhoA was a host restriction factor that inhibited PRV replication, which may deepen our understanding the pathogenesis of PRV and provide further insight into the prevention of PRV infection and the development of anti-viral drugs.


Assuntos
Herpesvirus Suídeo 1 , Pseudorraiva , Suínos , Animais , Herpesvirus Suídeo 1/fisiologia , Actinas , Linhagem Celular , Replicação Viral
7.
Org Biomol Chem ; 21(9): 1878-1882, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36789479

RESUMO

Pd-catalyzed ortho-C(sp3)-H arylation of aromatic aldehydes using 2-amino-N-methyl-acetamide as a simple, efficient and commercially available L,L-type transient directing group (TDG) is reported. The reaction exhibited excellent substrate compatibility and generated the desired products in moderate-to-high yields up to 78%. Further acid-catalyzed cyclization and dehydrative aromatization were also tested, and furnished some polycyclic aromatic hydrocarbons with excellent yields up to 96%. The X-ray crystal structure of a 2-methylbenzaldehyde ortho-C(sp3)-H palladation intermediate was obtained. Then, a plausible reaction mechanism involving the formation of a [5,6]-fused palladacycle was proposed. This approach offers valuable insights for exploiting novel L,L-type TDGs.

8.
Reprod Biol Endocrinol ; 20(1): 45, 2022 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-35255928

RESUMO

Diabetes mellitus (DM), a high incidence metabolic disease, is related to the impairment of male spermatogenic function. Spermidine (SPM), one of the biogenic amines, was identified from human seminal plasma and believed to have multiple pharmacological functions. However, there exists little evidence that reported SPM's effects on moderating diabetic male spermatogenic function. Thus, the objective of this study was to investigate the SPM's protective effects on testicular spermatogenic function in streptozotocin (STZ)-induced type 1 diabetic mice. Therefore, 40 mature male C57BL/6 J mice were divided into four main groups: the control group (n = 10), the diabetic group (n = 10), the 2.5 mg/kg SPM-treated diabetic group (n = 10) and the 5 mg/kg SPM-treated diabetic group (n = 10), which was given intraperitoneally for 8 weeks. The type 1 diabetic mice model was established by a single intraperitoneal injection of STZ 120 mg/kg. The results showed that, compare to the control group, the body and testis weight, as well the number of sperm were decreased, while the rate of sperm malformation was significantly increased in STZ-induced diabetic mice. Then the testicular morphology was observed, which showed that seminiferous tubule of testis were arranged in mess, the area and diameter of which was decreased, along with downregulated anti-apoptotic factor (Bcl-2) expression, and upregulated pro-apoptotic factor (Bax) expression in the testes. Furthermore, testicular genetic expression levels of Sertoli cells (SCs) markers (WT1, GATA4 and Vimentin) detected that the pathological changes aggravated observably, such as the severity of tubule degeneration increased. Compared to the saline-treated DM mice, SPM treatment markedly improved testicular function, with an increment in the body and testis weight as well as sperm count. Pro-apoptotic factor (Bax) was down-regulated expression with the up-regulated expression of Bcl-2 and suppression of apoptosis in the testes. What's more, expression of WT1, GATA4, Vimentin and the expressions of glycolytic rate-limiting enzyme genes (HK2, PKM2, LDHA) in diabetic testes were also upregulated by SPM supplement. The evidence derived from this study indicated that the SMP's positive effect on moderating spermatogenic disorder in T1DM mice's testis. This positive effect is delivered via promoting spermatogenic cell proliferation and participating in the glycolytic pathway's activation.


Assuntos
Diabetes Mellitus Experimental , Glicólise/efeitos dos fármacos , Infertilidade Masculina , Espermatogênese/efeitos dos fármacos , Espermidina/farmacologia , Animais , Complicações do Diabetes/tratamento farmacológico , Complicações do Diabetes/metabolismo , Complicações do Diabetes/patologia , Complicações do Diabetes/fisiopatologia , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Infertilidade Masculina/tratamento farmacológico , Infertilidade Masculina/etiologia , Infertilidade Masculina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Análise do Sêmen , Espermatogênese/fisiologia , Espermidina/uso terapêutico , Estreptozocina , Testículo/efeitos dos fármacos , Testículo/metabolismo
9.
Cell Commun Signal ; 20(1): 61, 2022 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-35534864

RESUMO

OBJECTIVE: Polycystic ovary syndrome (PCOS) is characterized by follicular dysplasia. An insufficient glycolysis-derived energy supply of granulosa cells (GCs) is an important cause of follicular dysplasia in PCOS. Follicular fluid (FF) exosomal microRNAs (miRNAs) have been proven to regulate the function of GCs. In this study, exosomes extracted from clinical FF samples were used for transcriptome sequencing (RNA-seq) analysis, and a human ovarian granulocyte tumour cell line (KGN cells) was used for in vitro mechanistic studies. METHODS AND RESULTS: In FF exosomal RNA-seq analysis, a decrease in glycolysis-related pathways was identified as an important feature of the PCOS group, and the differentially expressed miR-143-3p and miR-155-5p may be regulatory factors of glycolysis. By determining the effects of miR-143-3p and miR-155-5p on hexokinase (HK) 2, pyruvate kinase muscle isozyme M2 (PKM2), lactate dehydrogenase A (LDHA), pyruvate, lactate and apoptosis in KGN cells, we found that upregulated miR-143-3p expression in exosomes from the PCOS group inhibited glycolysis in KGN cells; knockdown of miR-143-3p significantly alleviated the decrease in glycolysis in KGN cells in PCOS. MiR-155-5p silencing attenuated glycolytic activation in KGN cells; overexpression of miR-155-5p significantly promoted glycolysis in KGN cells in PCOS. In this study, HK2 was found to be the mediator of miR-143-3p and miR-155-5p in FF-derived exosome-mediated regulation of glycolysis in KGN cells. Reduced glycolysis accelerated apoptosis of KGN cells, which mediated follicular dysplasia through ATP, lactate and apoptotic pathways. CONCLUSIONS: In conclusion, these results indicate that miR-143-3p and miR-155-5p in FF-derived exosomes antagonistically regulate glycolytic-mediated follicular dysplasia of GCs in PCOS. Video Abstract.


Assuntos
MicroRNAs , Síndrome do Ovário Policístico , Proliferação de Células , Feminino , Líquido Folicular/metabolismo , Glicólise , Células da Granulosa/metabolismo , Células da Granulosa/patologia , Humanos , Lactatos/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Síndrome do Ovário Policístico/genética , Síndrome do Ovário Policístico/metabolismo , Síndrome do Ovário Policístico/patologia
10.
J Biochem Mol Toxicol ; 36(6): e23038, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35307907

RESUMO

Antioxidants may provide a complementary treatment for patients with chronic diseases. Nevertheless, studies that have measured the effects of antioxidant on diabetes complications have provided conflicting results. This study aimed to elucidate the association between antioxidant and diabetic complications and to develop robust evidence for clinical decisions by systematic reviews and meta-analysis. PubMed, Embase, The Cochrane Library, Web of Science, Scopus databases were searched to collect clinical studies related to the efficacy of antioxidants in the treatment of diabetes complications from inception to May 5, 2021. Statistical meta-analyses were performed using the RevMan 5.4 software. Stata16 software was used to detect publication bias. The data of diabetic nephropathy (DN), diabetic nonalcoholic fatty liver disease (NAFLD), and diabetic periodontitis were collected to analyze the effect of antioxidant on diabetes and the above three complications. The meta-analysis results showed that antioxidant treatment was associated with significantly changes in the fasting plasma glucose (FPG) (standardized mean difference [SMD]: - 0.21 [95% confidence interval [CI]: - 0.33, -0.10], p < 0.001), hemoglobin A1c (HbA1c) (MD: - 0.41 [95% CI: - 0.63, -0.18], p < 0.001), total antioxidant capacity (TAC) (SMD: 0.44 [95% CI: 0.24, 0.63], p < 0.001) and malondialdehyde (MDA) (SMD: - 0.82 [95% CI: - 1.24, -0.41], p < 0.001) than the control group. Antioxidant supplements have the potential to treat three complications of diabetes. In conclusion, the meta-analysis results indicate that antioxidant treatment is effective clinically for diabetes mellitus and its complications.


Assuntos
Diabetes Mellitus Tipo 2 , Nefropatias Diabéticas , Antioxidantes/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Nefropatias Diabéticas/tratamento farmacológico , Suplementos Nutricionais , Hemoglobinas Glicadas , Humanos
11.
J Opt Soc Am A Opt Image Sci Vis ; 39(10): 1839-1848, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36215556

RESUMO

The effective deployment of an intelligent reflecting mirror array (IRMA) can enhance channel quality and improve the system performance in visible light communications (VLC) systems. This paper focuses on the performance analysis and parameter optimization of an IRMA-aided VLC system. Initially, the channel gains of both line-of-sight (LoS) link and non-LoS links are analyzed. Then, considering the blockage probability of a LoS link, a theoretical expression of the average bit error rate (ABER) is derived. To further improve the system performance, the optimization problems about the parameters of the IRMA are formulated, and schemes are proposed to solve these problems. Moreover, a kind of hardware implementation of the IRMA is provided. Numerical results verify the accuracy of the derived ABER expression and the effectiveness of the proposed schemes.

12.
Acta Biochim Biophys Sin (Shanghai) ; 54(9): 1314-1324, 2022 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-35929593

RESUMO

Spermatogenic dysfunction is one of the major secondary complications of diabetes; however, the underlying mechanisms remain ill-defined, and there is no available drug or strategy for the radical treatment of diabetic spermatogenic dysfunction. Therefore, the objective of this study is to investigate the protective effects of nicotinamide mononucleotide (NMN) on testicular spermatogenic function in streptozotocin (STZ)-induced diabetic mice. The results show that oral administration of NMN significantly increases the body and testis weight and the number of sperms. Moreover, the abnormal sperm count and the rate of sperm malformation are significantly decreased compared with the saline-treated diabetic mice. Histological analysis reveals that NMN treatment significantly increases the area and diameter of seminiferous tubules, accompanied by an increased number of spermatogenic cells and sperms. Immunohistochemistry and qRT-PCR results show that NMN increases Bcl-2 expression and decreases Bax expression in the testis. NMN also increases the protein expression of Vimentin and the mRNA expressions of WT1 and GATA4. In addition, qRT-PCR, western blot analysis and immunohistochemistry results also show that NMN increases the expressions of glycolysis-related rate-limiting enzymes including HK2, PKM2, and LDHA. In summary, this study demonstrates the protective effects of NMN on the testis in an STZ-induced diabetic mice model. NMN exerts its protective effects via reducing spermatogenic cell apoptosis by regulating glycolysis of Sertoli cells in diabetic mice. This study provides an experimental basis for the future clinical application of NMN in diabetes-induced spermatogenic dysfunction.


Assuntos
Diabetes Mellitus Experimental , Mononucleotídeo de Nicotinamida , Masculino , Camundongos , Animais , Mononucleotídeo de Nicotinamida/efeitos adversos , Mononucleotídeo de Nicotinamida/metabolismo , Estreptozocina/efeitos adversos , Diabetes Mellitus Experimental/induzido quimicamente , Sêmen/metabolismo , Glicólise
13.
J Opt Soc Am A Opt Image Sci Vis ; 38(5): 654-662, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33983270

RESUMO

In previous studies, the receivers in indoor visible light communication (VLC) were usually fixed. However, in reality, the receivers in VLC have random locations and orientations. Therefore, it is important to consider these random factors for performance analysis in VLC. In this paper, we consider a typical VLC system with a fixed transmitter and a random receiver. Two types of receivers are investigated: (1) those with random location and (2) those with random orientation. Based on the established system model, the statistical characteristics of the channel were obtained, and closed-form expressions of the average channel capacity and the outage probability were derived, respectively. Finally, numerical results verified the accuracy of derived theoretical expressions. Moreover, the effects of the nominal optical intensity, the dimming target, the transmitter height, the receiver zone's radius, the outage threshold, and the Lambertian emission order on system performance were also provided.

14.
Entropy (Basel) ; 23(12)2021 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-34945902

RESUMO

This paper focuses on an unmanned aerial vehicle (UAV) assisted hybrid free-space optical (FSO)/radio frequency (RF) communication system. Considering the rate imbalance between the FSO and RF links, a buffer is employed at the UAV. Initially, theoretical models of energy consumption and throughput are obtained for the hybrid system. Based on these models, the theoretical expression of the energy efficiency is derived. Then, a nonconvex trajectory optimization problem is formulated by maximizing the energy efficiency of the hybrid system under the buffer constraint, velocity constraint, acceleration constraint, start-end position constraint, and start-end velocity constraint. By using the sequential convex optimization and first-order Taylor approximation, the nonconvex problem is transformed into a convex one. An iterative algorithm is proposed to solve the problem. Numerical results verify the efficiency of the proposed algorithm and also show the effects of buffer size on a UAV's trajectory.

15.
Acta Oncol ; 59(8): 933-939, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32568616

RESUMO

Background: Efficient and accurate methods are needed to automatically segmenting organs-at-risk (OAR) to accelerate the radiotherapy workflow and decrease the treatment wait time. We developed and evaluated the use of a fused model Dense V-Network for its ability to accurately segment pelvic OAR.Material and methods: We combined two network models, Dense Net and V-Net, to establish the Dense V-Network algorithm. For the training model, we adopted 100 kV computed tomography (CT) images of patients with cervical cancer, including 80 randomly selected as training sets, by which to adjust parameters of the automatic segmentation model, and the remaining 20 as test sets to evaluate the performance of the convolutional neural network model. Three representative parameters were used to evaluate the segmentation results quantitatively.Results: Clinical results revealed that Dice similarity coefficient values of the bladder, small intestine, rectum, femoral head and spinal cord were all above 0.87 mm; and Jaccard distance was within 2.3 mm. Except for the small intestine, the Hausdorff distance of other organs was less than 9.0 mm. Comparison of our approaches with those of the Atlas and other studies demonstrated that the Dense V-Network had more accurate and efficient performance and faster speed.Conclusions: The Dense V-Network algorithm can be used to automatically segment pelvic OARs accurately and efficiently, while shortening patients' waiting time and accelerating radiotherapy workflow.


Assuntos
Redes Neurais de Computação , Órgãos em Risco/diagnóstico por imagem , Pelve/diagnóstico por imagem , Neoplasias do Colo do Útero/diagnóstico por imagem , Fluxo de Trabalho , Algoritmos , Aprendizado Profundo , Feminino , Fêmur/diagnóstico por imagem , Humanos , Intestinos/diagnóstico por imagem , Reto/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Tempo para o Tratamento , Bexiga Urinária/diagnóstico por imagem , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/cirurgia
17.
Opt Express ; 25(19): 22805-22819, 2017 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-29041587

RESUMO

This paper analyzes the received power distribution of a generalized indoor visible light communication (VLC) system. The generalization includes: both ceiling-mounted and wall-mounted layouts are considered on the transmitting end to cover some special scenarios; a generally applicable sum-of-sine luminous intensity pattern (SSLIP) is used to fit light emitting diodes (LEDs)' radiation curve; the receiver is considered to have a large light receiving area (LRA) with non-uniformly distributed received power. Through mathematical calculation, the expression of received power at any point of the room is derived. Using the expression, the impact of transmitting LEDs' radiation pattern on received power performance is investigated. It is suggested that in the ceiling-mounted scenario, the LED transmitters with sharp luminous intensity patterns have bigger received power variations and shorter optimal receiving distances. In the wall-mounted case in contrast, sharp luminous intensity patterns lead to smaller received power variations and longer optimal receiving distances.

19.
Opt Express ; 24(12): 13060-74, 2016 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-27410325

RESUMO

Multi-input multi-output (MIMO) technique is attractive for visible light communication (VLC), which exploits the high signal-to-noise ratio (SNR) of a single channel to overcome the capacity limitation due to the small modulation bandwidth of the light emitting diode. This paper establishes a MIMO VLC system under the non-negativity, peak power and dimmable average power constraints. Assume that perfect channel state information at the transmitter is known, the MIMO channel is changed to parallel, non-interfering sub-channels by using the singular value decomposition (SVD). Based on the SVD, the lower bound on the channel capacity for MIMO VLC is derived by employing entropy power inequality and variational method. Moreover, by maximizing the derived lower bound on the capacity under the given constraints, the receiver deployment optimization problem is formulated. The problem is solved by employing the principle of particle swarm optimization. Numerical results verify the derived capacity bound and the proposed deployment optimization scheme.

20.
Org Biomol Chem ; 14(10): 2978-84, 2016 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-26881829

RESUMO

A highly efficient one-pot synthesis of imidazo[2,1-b]thiazole derivatives has been developed and proceeds via a ring-opening and ring-closing reconstruction of imidazo[2,1-b][1,3,4]thiadiazoles with phenylacetylene in the presence of potassium tert-butoxide (t-BuOK) under very mild reaction conditions. A proposed mechanism is calculated computationally using a DFT method at the B3LYP/6-31+G(d,p) level. The imidazo[2,1-b][1,3,4]thiadiazoles are also successfully converted to a series of 2-(arylthio)-1H-imidazoles using aryl halide as a reactant and copper(ii) acetylacetonate (Cu(acac)2) as a catalyst under microwave irradiation conditions. The key features of these reactions are the use of readily available reagents, simple operation, the convenient utilization of new heterocyclic synthons, and a great variety of substrates with functional group compatibility.

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