High energy and power density nanotube-enhanced ultracapacitor design, modeling, testing, and predicted performance

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 161-164).Today's batteries are penalized by their poor cycleability (limited to few thousand cycles), shelf life, and inability to quickly recharge (limited to tens of minutes). Commercial ultracapacitors are energy storage systems that solve these problems by offering more than one million recharges with little capacitance degradation, recharge times on the order of few seconds, and unlimited shelf life. However, today's ultracapacitors are limited by their low energy stored per unit of volume and weight (5% that of a lithium ion battery), and their high cost (ten times greater than that of lithium ion batteries) per unit of energy stored. This thesis presents vertical carbon nanotubes-based electrodes designed to achieve, when packaged into an ultracapacitor cell, a four to seven times higher power density (7.8 kW/1) and a five times higher energy density (31 Wh/1) than those of activated carbon-based ultracapacitors. Models to predict the energy density, power density, and efficiency of an ultracapacitor cell using vertical carbon nanotube electrodes of a given morphology are described. The synthesis of carbon nanotube electrodes fabricated on thin conducting substrates of tungsten and aluminum that have the target nanotube average diameters and lengths is described along with insights on the thermodynamics of the nanotube growth reaction. The low pressure chemical vapor deposition reactor used to fabricate nanotube electrodes on conducting substrates is described. Electrochemical measurements of electrodes are presented to corroborate electrochemical modeling leading to the performance prediction of carbon nanotube-based ultracapacitors. Finally, some key remaining questions to further advance the understanding of nanotubes as electrode materials for ultracapacitor are presented.by Riccardo Signorelli.Ph.D

Role of Sphingolipids in the Pathobiology of Lung Inflammation

Sphingolipid bioactivities in the respiratory airways and the roles of the proteins that handle them have been extensively investigated. Gas or inhaled particles or microorganisms come into contact with mucus components, epithelial cells, blood barrier, and immune surveillance within the airways. Lung structure and functionality rely on a complex interplay of polar and hydrophobic structures forming the surfactant layer and governing external-internal exchanges, such as glycerol-phospholipids sphingolipids and proteins. Sphingolipids act as important signaling mediators involved in the control of cell survival and stress response, as well as secreted molecules endowed with inflammation-regulatory activities. Most successful respiratory infection and injuries evolve in the alveolar compartment, the critical lung functional unit involved in gas exchange. Sphingolipid altered metabolism in this compartment is closely related to inflammatory reaction and ceramide increase, in particular, favors the switch to pathological hyperinflammation. This short review explores a few mechanisms underlying sphingolipid involvement in the healthy lung (surfactant production and endothelial barrier maintenance) and in a selection of lung pathologies in which the impact of sphingolipid synthesis and metabolism is most apparent, such as acute lung injury, or chronic pathologies such as cystic fibrosis and chronic obstructive pulmonary disease. A Brief Overview on Sphingolipids within the Lung Environment The interest in sphingolipid presence and bioactivities in the respiratory airways has produced a steady number of reports since the 1970s. However, a host of publications in the last few years have provided an increasingly detailed picture of the role played in the lungs by this class of lipids and by the proteins that handle them. As vital respiratory organs that mediate air-blood gas exchanges, lungs must undergo delicate and tightly controlled developmental transitions. Antenatally, a 20-week human fetus displays lungs that have branched to generate all airways, but it is not before ∼28 weeks of gestation that alveolarization begins from primordial saccular structures and type I alveolar cells differentiate from the cuboidal epithelium. Concomitantly, at this stage endothelial cells shape the alveolar capillary bed and type II alveolar cells appear, to demarcate alveolar septal junctions. Type II cells start producing surfactant, which accumulates to increasing concentrations by term. The initiation of autonomous ventilation at birth represents a dramatic switch in postnatal lung function. While throughout gestation a chloride-ion driven liquid secretion creates a positive pressure that distends the lungs and stimulates growth, a sudden reversal from net secretion to net adsorption takes place at birth under the effect of O 2 and hormones (epinephrine, glucocorticoids, and thyroid hormones), enabling the rapid elimination of lung liquid. From this moment on, lung lumen will maintain a low-level chloride-ion based liquid secretion to generate a surface liquid layer, known as surfactant and formed by specific secreted lipids and proteins, and a robust absorptive capacity will prevent alveolar flooding and edema. Equally important, being permanently exposed to inhaled particles and microorganisms from birth, pulmonary immunity must be tuned to effectively dispose of them, while minimizing immunopathology to preserve appropriate gas exchange. Thus, the first-line lung defenses, prior to immunity, are based on mechanical weapons including cilia, mucus, and the cough reflex, which concur to prevent pathogen access to the lower airways and in so doing avoid an overt inflammatory response. This is one of the major reasons why lungs are particularly sensitive to the sphingolipid (and Hindawi Publishing Corporatio

Visualization of in Vivo Direct Interaction between HIV-1 TAT and Human Cyclin T1 in Specific Subcellular Compartments by Fluorescence Resonance Energy Transfer

n/

Myriocin modulates the altered lipid metabolism and storage in cystic fibrosis.

Cystic fibrosis (CF) is a hereditary disease mostly related to ΔF508 CFTR mutation causing a proteinopathy that is characterized by multiple organ dysfunction, primarily lungs chronic inflammation, and infection. Defective autophagy and accumulation of the inflammatory lipid ceramide have been proposed as therapeutic targets. Accumulation of lipids and cholesterol was reported in the airways of CF patients, together with altered triglycerides and cholesterol levels in plasma, thus suggesting a disease-related dyslipidemia. Myriocin, an inhibitor of sphingolipids synthesis, significantly reduces inflammation and activates TFEB-induced response to stress, enhancing fatty acids oxidation and promoting autophagy. Myriocin ameliorates the response against microbial infection in CF models and patients' monocytes. Here we show that CF broncho-epithelial cells exhibit an altered distribution of intracellular lipids. We demonstrated that lipid accumulation is supported by an enhanced synthesis of fatty acids containing molecules and that Myriocin is able to reduce such accumulation. Moreover, Myriocin modulated the transcriptional profile of CF cells in order to restore autophagy, activate an anti-oxidative response, stimulate lipid metabolism and reduce lipid peroxidation. Moreover, lipid storage may be altered in CF cells, since we observed a reduced expression of lipid droplets related proteins named perilipin 3 and 5 and seipin. To note, Myriocin up-regulates the expression of genes that are involved in lipid droplets biosynthesis and maturation. We suggest that targeting sphingolipids de novo synthesis may counteract lipids accumulation by modulating CF altered transcriptional profile, thus restoring autophagy and lipid metabolism homeostasis

Development of highly sensitive nanoscale transition edge sensors for gigahertz astronomy and dark matter search

Terahertz and sub-terahertz band detection has a key role both in fundamental interactions physics and technological applications, such as medical imaging, industrial quality control and homeland security. In particular, transition edge sensors (TESs) and kinetic inductance detectors (KIDs) are the most employed bolometers and calorimeters in the THz and sub-THz band for astrophysics and astroparticles research. Here, we present the electronic, thermal and spectral characterization of an aluminum/copper bilayer sensing structure that, thanks to its thermal properties and a simple miniaturized design, could be considered a perfect candidate to realize an extremely sensitive class of nanoscale TES (nano-TES) for the giga-therahertz band. Indeed, thanks to the reduced dimensionality of the active region and the efficient Andreev mirror (AM) heat confinement, our devices are predicted to reach state-of-the-art TES performance. In particular, as a bolometer the nano-TES is expected to have a noise equivalent power (NEP) of $5\times10^{-20}$ W/$\sqrt{\mathrm{Hz}}$ and a relaxation time of $\sim 10$ ns for the sub-THz band, typical of cosmic microwave background studies. When operated as single-photon sensor, the devices are expected to show a remarkable frequency resolution of 100 GHz, pointing towards the necessary energy sensitivity requested in laboratory axion search experiments. Finally, different multiplexing schemes are proposed and sized for imaging applications.Comment: 12 page, 7 figure

Smoking Addiction in Patients with Schizophrenia Spectrum Disorders and Its Perception and Intervention in Healthcare Personnel Assigned to Psycho-Rehabilitation Programs: A Qualitative Research

Patients with schizophrenia spectrum disorders have a higher prevalence and frequency of smoking rates when compared to the rest of the population; to this, it must be added that they develop a greater dependence and have some worse health consequences than the general population. This is qualitative research on the perception of smoking in healthcare professionals assigned to psycho-rehabilitation programs for patients with schizophrenia spectrum disorders. The point of view of health personnel (Psychologists, Psychiatrists, Pedagogists, and Nurses) about cigarette smoking in these patients was analyzed, focusing on their implications in disturbance and comparing them with e-cigarettes too. The methodology used to collect the data was a semi-structured interview with five questions. The research path was carried out in two assisted therapeutic communities that are clinics for the rehabilitation of serious mental illness in the period between November and July 2022. The results showed that the opinion of health professionals on smoking is very negative. Research has also shown that nearly all patients are smokers; however, their high grade of addiction is caused by periods of high stress due to various factors that lead patients to consume a greater number of cigarettes. Almost all respondents have a positive opinion of the e-cigarette, which was defined as an excellent substitute for traditional cigarettes

Smoking Addiction in Patients with Schizophrenia Spectrum Disorders and Its Perception and Intervention in Healthcare Personnel Assigned to Psycho-Rehabilitation Programs: A Qualitative Research

Patients with schizophrenia spectrum disorders have a higher prevalence and frequency of smoking rates when compared to the rest of the population; to this, it must be added that they develop a greater dependence and have some worse health consequences than the general population. This is qualitative research on the perception of smoking in healthcare professionals assigned to psycho-rehabilitation programs for patients with schizophrenia spectrum disorders. The point of view of health personnel (Psychologists, Psychiatrists, Pedagogists, and Nurses) about cigarette smoking in these patients was analyzed, focusing on their implications in disturbance and comparing them with e-cigarettes too. The methodology used to collect the data was a semi-structured interview with five questions. The research path was carried out in two assisted therapeutic communities that are clinics for the rehabilitation of serious mental illness in the period between November and July 2022. The results showed that the opinion of health professionals on smoking is very negative. Research has also shown that nearly all patients are smokers; however, their high grade of addiction is caused by periods of high stress due to various factors that lead patients to consume a greater number of cigarettes. Almost all respondents have a positive opinion of the e-cigarette, which was defined as an excellent substitute for traditional cigarettes

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review

Purpose: The extent of resection (EOR) is an independent prognostic factor for overall survival (OS) in adult patients with Glioma Grade 4 (GG4). The aim of the neuro-oncology section of the Italian Society of Neurosurgery (SINch®) was to provide a general overview of the current trends and technical tools to reach this goal. Methods: A systematic review was performed. The results were divided and ordered, by an expert team of surgeons, to assess the Class of Evidence (CE) and Strength of Recommendation (SR) of perioperative drugs management, imaging, surgery, intraoperative imaging, estimation of EOR, surgery at tumor progression and surgery in elderly patients. Results: A total of 352 studies were identified, including 299 retrospective studies and 53 reviews/meta-analysis. The use of Dexamethasone and the avoidance of prophylaxis with anti-seizure medications reached a CE I and SR A. A preoperative imaging standard protocol was defined with CE II and SR B and usefulness of an early postoperative MRI, with CE II and SR B. The EOR was defined the strongest independent risk factor for both OS and tumor recurrence with CE II and SR B. For intraoperative imaging only the use of 5-ALA reached a CE II and SR B. The estimation of EOR was established to be fundamental in planning postoperative adjuvant treatments with CE II and SR B and the stereotactic image-guided brain biopsy to be the procedure of choice when an extensive surgical resection is not feasible (CE II and SR B). Conclusions: A growing number of evidences evidence support the role of maximal safe resection as primary OS predictor in GG4 patients. The ongoing development of intraoperative techniques for a precise real-time identification of peritumoral functional pathways enables surgeons to maximize EOR minimizing the post-operative morbidity

Lopinavir/Ritonavir and Darunavir/Cobicistat in Hospitalized COVID-19 Patients: Findings From the Multicenter Italian CORIST Study

Background: Protease inhibitors have been considered as possible therapeutic agents for COVID-19 patients. Objectives: To describe the association between lopinavir/ritonavir (LPV/r) or darunavir/cobicistat (DRV/c) use and in-hospital mortality in COVID-19 patients. Study Design: Multicenter observational study of COVID-19 patients admitted in 33 Italian hospitals. Medications, preexisting conditions, clinical measures, and outcomes were extracted from medical records. Patients were retrospectively divided in three groups, according to use of LPV/r, DRV/c or none of them. Primary outcome in a time-to event analysis was death. We used Cox proportional-hazards models with inverse probability of treatment weighting by multinomial propensity scores. Results: Out of 3,451 patients, 33.3% LPV/r and 13.9% received DRV/c. Patients receiving LPV/r or DRV/c were more likely younger, men, had higher C-reactive protein levels while less likely had hypertension, cardiovascular, pulmonary or kidney disease. After adjustment for propensity scores, LPV/r use was not associated with mortality (HR = 0.94, 95% CI 0.78 to 1.13), whereas treatment with DRV/c was associated with a higher death risk (HR = 1.89, 1.53 to 2.34, E-value = 2.43). This increased risk was more marked in women, in elderly, in patients with higher severity of COVID-19 and in patients receiving other COVID-19 drugs. Conclusions: In a large cohort of Italian patients hospitalized for COVID-19 in a real-life setting, the use of LPV/r treatment did not change death rate, while DRV/c was associated with increased mortality. Within the limits of an observational study, these data do not support the use of LPV/r or DRV/c in COVID-19 patients