34 research outputs found

    Perfect quantum excitation energy transport via single edge perturbation in a complete network

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    We consider quantum excitation energy transport (EET) in a network of two-state nodes in the Markovian approximation by employing the Lindblad formulation. We find that EET from an initial site, where the excitation is inserted to the sink, is generally inefficient due to the inhibition of transport by localization of the excitation wave packet in a symmetric, fully-connected network. We demonstrate that the EET efficiency can be significantly increased up to ≈100% by perturbing hopping transport between the initial node and the one connected directly to the sink, while the rate of energy transport is highest at a finite value of the hopping parameter. We also show that prohibiting hopping between the other nodes which are not directly linked to the sink does not improve the efficiency. We show that external dephasing noise in the network plays a constructive role for EET in the presence of localization in the network, while in the absence of localization it reduces the efficiency of EET. We also consider the influence of off-diagonal disorder in the hopping parameters of the network

    Complete Versus Incomplete Surgical Resection in Intramedullary Astrocytoma: Systematic Review with Individual Patient Data Meta-Analysis

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    Study Design: Systematic review Background: Considering the infiltrative nature of intramedullary astrocytoma, the goal of surgery is to have a better patient related outcome. Objective: To compare the overall survival (OS) and neurologic outcomes of complete vs incomplete surgical resection for patients with intramedullary astrocytoma. Methods: A comprehensive search of MEDLINE, CENTRAL and EMBASE was conducted by two independent reviewers. Individual patient data (IPD) analysis and multivariate Cox Proportional Hazard Model was developed to measure the effect of surgical strategies on OS, post-operative neurological improvement (PNI), and neurological improvement in the last follow up (FNI). Results: We included 1079 patients from 35 studies. Individual patient data of 228 patients (13 articles) was incorporated into the integrative IPD analysis. Kaplan-Meier survival analysis showed complete resection (CR) significantly improved OS in comparison with the incomplete resection (IR) (log-rank test, P =.004). In the multivariate IPD analysis, three prognostic factors had significant effect on the OS: (1) Extent of Resection, (2) pathology grade, and (3) adjuvant therapy. We observed an upward trend in the popularity of chemotherapy, but CR, IR, and radiotherapy had relatively stable trends during three decades. Conclusion: Our study shows that CR can improve OS when compared to IR. Patients with spinal cord astrocytoma undergoing CR had similar PNI and FNI compared to IR. Therefore, CR should be the primary goal of surgery, but intraoperative decisions on the extent of resection should be relied on to prevent neurologic adverse events. Due to significant effect of adjuvant therapy on OS, PNI and FNI, it could be considered as the routine treatment strategy for spinal cord astrocytoma

    Complete Versus Incomplete Surgical Resection in Intramedullary Ependymomas: A Systematic Review and Meta-analysis

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    Study Design: Systematic review. Objective: To compare outcomes of complete versus incomplete resection in primary intramedullary spinal cord ependymoma. Methods: A comprehensive search of the MEDLINE, CENTRAL, and Embase databases was conducted by 2 independent investigators. Random-effect meta-analysis and meta-regression with seven covariates were performed to evaluate the reason for the heterogeneity among studies. We also used individual patient data in the integrative analysis to compare complete and incomplete resection based on 4 outcomes: progression-free survival (PFS), overall survival (OS), postoperative neurological improvement (PNI), and follow-up neurological improvement (FNI). Results: A total of 23 studies were identified, including 407 cases. Significant heterogeneity among included studies was observed in risk estimates (I2 for PFS, FNI, and PNI were 49.5%, 78.3%, and 87.2%, respectively). The mean follow-up time across cases was 48.6 ± 2.35 months. Cox proportional multivariable analysis revealed that the complete resection can prolong PFS (model, hazard ratio = 0.18, CI 0.05-0.54, P =.004,) and improve the FNI (binary logistic regression, adjusted odds ratio = 16.5, CI 1.6-171, P =.019). However, PNI and OS were similar in patients with incomplete resected spinal cord ependymoma compared with complete resection (binary logistic regression respectively and Cox multivariable analysis, P >.5). Conclusion: The data presented in this study showed that OS was not significantly affected by the degree of surgery. However, complete resection of intramedullary ependymomas provides the optimal outcomes with longer PFS and better long-term neurological outcomes than incomplete resection

    Evaluating the Serum Levels of CCL17, CCL22, and CCL28 Chemokines and the Gene Expression of α4β1 and α4β7 Integrins in Patients With Allergic Rhinitis

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    Allergic rhinitis (AR) is a chronic inflammatory disease involving the nasal mucosa. Leukocytes recruitment to the inflammation sites is controlled by chemokines, cytokines, and adhesion molecules. Retinoic acid (RA), a vitamin A metabolite, plays an essential role in mucosal immunity and the production of inflammatory cytokines and chemokines. This study intended to evaluate the serum levels of RA, CCL17, CCL22, CCL28, and the mRNA expression levels of α4, β1, and β7 integrins in AR patients compared to healthy subjects. Peripheral blood was collected from 37 patients with AR and 30 age- and gender-matched healthy individuals. Serum levels of RA, CCL17, CCL22, and CCL28 were measured by the enzyme-linked immunosorbent assay (ELISA) technique, and the mRNA expression levels for α4, β1, and β7 integrins were assessed using the quantitative real-time PCR method. Our results showed that the serum levels of CCL22 and CCL28 chemokines are significantly higher in the AR group compared to the healthy controls (P<0.01). However, the gene expression of the β1 integrin in the AR group was significantly lower than that of the control group (P<0.001). Besides, there was a positive association between serum RA and CCL17 levels in patients (P<0.0001, r=0.6). In conclusion, increased serum levels of CCL22 and CCL28 chemokines, as well as decreased gene expression of β1 integrin in AR patients, may contribute to the pathogenesis and/or exacerbation of AR

    The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

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    Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

    The Effect of glial cells inhibition on the progression of seizures induced by chemical kindling in male rats

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    Background &amp; Objectives: Considering the role of glial cells in synaptic transmission, regulation of neurotransmitter concentration in synaptic cleft, K+ buffering, and releasing the gliotransmitters, the purpose of this study is to investigate the effect of glial cells inhibition on the progression of seizures induced by chemical kindling in rats. Materials &amp; Methods: In chemical kindling, animals received Pentylenetetrazol, 35 mg/kg each 48 hours, intraperitoneally and five different stages of seizure were appeared gradually and seizure parameters including maximum seizure stage (SS), stage 4 latency (S4L), stage 4&amp;5 duration (S5D), and seizure duration (SD) were measured during 20 min after PTZ injection. Then seizure parameters were evaluated in animals treated with intracerebroventricular (icv) administration of Fluorocitrate (as a glial cells inhibitor), injected 30 min before PTZ, and compared with PTZ treated animals. Results: Results showed that glial cells inhibition with ICV injection of Fluorocitrate decreased SS, S5D, and SD and increased S4L significantly (P<0.05, P<0.01, P<0.001). Â Conclusion: On the basis of obtained results, it may be concluded that glial cells inhibition reduces spreading rate of epileptiform activity in the nervous system, and the duration of neuronal hyperexcitability and, also, prevents the progression of seizure to final stages

    Validity Examination of the Dissipative Quantum Model of Olfaction

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    A study of the diagnostic value of Inhibin A Tests for occurrence of preeclampsia in pregnant women

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    Background: Hypertensive disorders are common during pregnancy, and are among 3 important causes of maternal death. Preeclampsia occurs in 3 to 5% of pregnancies. Early diagnosis of this disorder can lead to better pregnancy outcomes. Objective: The aim of this study was to determine the relationship between inhibin A serum levels during second stage pregnancy screening tests, and incidence and severity of preeclampsia. Methods: In this study, 300 pregnant women who referred to Kowsar Hospital and carried out second stage pregnancy screening tests from September 2014 to March 2015 in Urmia city, Iran, were enrolled. Five ml venous blood samples were obtained from each participant, and inhibin A serum levels were evaluated in all cases. Finally, all the necessary information was obtained from the pregnancy files of participants after delivery, and gathered in a questionnaire. The data were analyzed using SPSS software version 18 and independent t-test, ANOVA and descriptive statistics were used. P-values less than 0.05 were considered significant. Results: Among the 300 pregnant women who were studied, the gestational age at the time of acquiring blood samples was as follows: 169 cases (56.3%) at 16-17 weeks, 77 cases (25.7%) at 18-19 weeks and 14 cases at 20 weeks (4.7%). In this study, MOM of inhibin A was more than 1.25 in 12 cases that finally, preeclampsia occurred in them. This relationship was statistically significant (p=0.001). The relationship between MOM of inhibin A and severe preeclampsia was evaluated, and the relationship was significant (p=0.004). The relationship between MOM of inhibin A and pregnancy hypertension was not significant (p=0.643). Conclusion: Considering the results of this study, we can conclude that MOM of inhibin A levels in maternal serum during second stage pregnancy screening tests can predict incidence and severity of developing preeclampsia in pregnant women. This is not true in cases of pregnancy hypertension

    The Physical Mechanism for Retinal Discrete Dark Noise: Thermal Activation or Cellular Ultraweak Photon Emission?

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    For several decades the physical mechanism underlying discrete dark noise of photoreceptors in the eye has remained highly controversial and poorly understood. It is known that the Arrhenius equation, which is based on the Boltzmann distribution for thermal activation, can model only a part (e.g. half of the activation energy) of the retinal dark noise experimentally observed for vertebrate rod and cone pigments. Using the Hinshelwood distribution instead of the Boltzmann distribution in the Arrhenius equation has been proposed as a solution to the problem. Here, we show that the using the Hinshelwood distribution does not solve the problem completely. As the discrete components of noise are indistinguishable in shape and duration from those produced by real photon induced photo-isomerization, the retinal discrete dark noise is most likely due to 'internal photons' inside cells and not due to thermal activation of visual pigments. Indeed, all living cells exhibit spontaneous ultraweak photon emission (UPE), mainly in the optical wavelength range, i.e., 350-700 nm. We show here that the retinal discrete dark noise has a similar rate as UPE and therefore dark noise is most likely due to spontaneous cellular UPE and not due to thermal activation
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