Phonon-assisted radiofrequency absorption by gold nanoparticles resulting in hyperthermia

It is suggested that in gold nanoparticles (GNPs) of about 5 nm sizes used in the radiofrequency (RF) hyperthermia, an absorption of the RF photon by the Fermi electron occurs with involvement of the longitudinal acoustic vibrational mode (LAVM), the dominating one in the distribution of vibrational density of states (VDOS). This physical mechanism helps to explain two observed phenomena: the size dependence of the heating rate (HR) in GNPs and reduced heat production in aggregated GNPs. The argumentation proceeds within the one-electron approximation, taking into account the discretenesses of energies and momenta of both electrons and LAVMs. The heating of GNPs is thought to consist of two consecutive processes: first, the Fermi electron absorbs simultaneously the RF photon and the LAVM available in the GNP; hereafter the excited electron gets relaxed within the GNP's boundary, exciting a LAVM with the energy higher than that of the previously absorbed LAVM. GNPs containing the Ta and/or Fe impurities are proposed for the RF hyperthermia as promising heaters with enhanced HRs, and GNPs with rare-earth impurity atoms are also brought into consideration. It is shown why the maximum HR values should be expected in GNPs with about 5-7 nm size.Comment: proceedings at the NATO Advanced Research workshop FANEM-2015 (Minsk, May 25-27, 2015). To be published in the final form in: "Fundamental and Applied NanoElectroMagnetics" (Springer Science + Business Media B.V.

How I Do It: High Flow, Non-invasive ventilation and Awake (non-intubation) Proning in Covid-19 Patients with Respiratory Failure.

The coronavirus disease 2019 pandemic will be remembered for the rapidity with which it spread, the morbidity and mortality associated with it, and the paucity of evidence-based management guidelines. One of the major concerns of hospitals was to limit spread of infection to health-care workers. Because the virus is spread mainly by respiratory droplets and aerosolized particles, procedures that may potentially disperse viral particles, the so-called “aerosol-generating procedures” were avoided whenever possible. Included in this category were noninvasive ventilation (NIV), high-flow nasal cannula (HFNC), and awake (nonintubated) proning. Accordingly, at many health-care facilities, patients who had increasing oxygen requirements were emergently intubated and mechanically ventilated to avoid exposure to aerosol-generating procedures. With experience, physicians realized that mortality of invasively ventilated patients was high and it was not easy to extubate many of these patients. This raised the concern that HFNC and NIV were being underutilized to avoid intubation and to facilitate extubation. In this article, we attempt to separate fact from fiction and perception from reality pertaining to the aerosol dispersion with NIV, HFNC, and awake proning. We describe precautions that hospitals and health-care providers must take to mitigate risks with these devices. Finally, we take a practical approach in describing how we use the three techniques, including the common indications, contraindications, and practical aspects of application

Imaging algorithm for COVID-19: A practical approach

© 2020 Elsevier Inc. The global pandemic of COVID-19 pneumonia caused by the novel coronavirus (SARS-CoV-2) has strained healthcare resources across the world with emerging challenges of mass testing, resource allocation and management. While reverse transcriptase-polymerase chain reaction (RT-PCR) test is the most commonly utilized test and considered the current gold standard for diagnosis, the role of chest imaging has been highlighted by several studies demonstrating high sensitivity of computed tomography (CT). Many have suggested using CT chest as a first-line screening tool for the diagnosis of COVID-19. However, with advancement of laboratory testing and challenges in obtaining a CT scan without significant risk to healthcare providers, the role of imaging in diagnosis has been questioned. Several imaging societies have released consensus statements and guidelines on utilizing imaging resources and optimal reporting. In this review, we highlight the current evidence on various modalities in thoracic imaging for the diagnosis of COVID-19 and describe an algorithm on how to use these resources in an optimal fashion in accordance with the guidelines and statements released by major imaging societies

Geopolímeros de metakaolin basados en potasio: papel de la relación K/Al y del curado en agua o con vapor a diferentes temperaturas

K-based geopolymer binder was prepared by reacting metakaolin with alkaline solutions having different potassium contents and by water curing at room temperature and 80 °C as well as steam curing at 150 and 180 °C. The phase formation, microstructure and Al and Si nearest neighbor environments were studied using XRD, TEM and 27Al and 29Si MAS NMR spectroscopy, respectively. The results revealed that amorphous alumino-silicates were predominant in geopolymer prepared by curing up to 28 days at room temperature or at 80 °C. The amorphous alumino-silicates persisted after hydrothermal treatment at 150 °C/48 hrs and even at 180 °C/30 hrs. However, the samples cured hydrothermally at 180 °C/48 hrs revealed formation of crystalline potassium aluminum silicate and chabazite phases. The Al nearest neighbor environments was not significantly affected by increasing the K/Al ratio up to 1.55 or by the curing temperatures. On the other hand, the geopolymer reaction appears to have increased when cured at 80 °C or steam cured at 150° and 180 °C and crystalline aluminosilicates resulted when the geopolymer sample was hydrothermally treated at 180 °C/48 hrs.Se prepararon geopolímeros por reacción de metacaolín con disoluciones alcalinas con diferentes contenidos de potasio. Se realizó un curado con agua a temperatura ambiente y a 80 °C, y con vapor de agua a 150 y 180 °C. La formación de las diferentes fases así como la microestructura y entornos del Al y Si se estudiaron mediante DRX, TEM y espectroscopia de RMN MAS de 27Al y 29Si. Los aluminosilicatos amorfos fueron predominantes en aquellos geopolímeros sometidos a curado de hasta 28 días a temperatura ambiente o a 80 °C. Los aluminosilicatos amorfos persistieron tras el tratamiento hidrotermal a 150 °C/48 horas e incluso a 180 °C/30 h. Sin embargo, las muestras curadas hidrotermalmente a 180 °C/48 h revelaron la formación de fases cristalinas de silicatos de aluminio y potasio, así como de chabazita. Los entornos de Al no resultaron afectados significativamente por el aumento de la relación K/Al de hasta 1.55, ni por las temperaturas de curado. Por otro lado, la reacción de geopolimerización aumentó cuando el curado se realizó a 80 °C o con curado a vapor a 150 y 180 °C

Antibacterial activity of deer musk and Ziziphus spina-christi against carbapebem resis-tant gram negative bacteria isolated from patients with burns and wounds

Bacteria were isolated from 250 specimens obtained from patients attending the Plastic Reconstructive and Burn Surgery Hospital in the Sulaymaniyah (Kurdistan region) and the burn and wound care units of the Azadi Teaching Hospital (Kirkuk), Iraq. Gram-negative bacteria were isolated from 100 (40%) of the samples which identified by BD phoenix, 66 isolates (66%) were carbapenem-resistant species, Rapidec® Carba NP test and sensitivity tests revealed 17 different genera and species of carbapenem-resistant bacteria. The BD Phoenix system was used to evaluate the susceptibility test of the isolates to 18 different antibiotics. The number of isolates that exhibited resistance to the carbapenem antibiotics, ertapenem, imipenem and meropenem, was 40 (61%), 35 (54%) and 28 (42%) respectively. Meanwhile, the number of isolates resistant to the penicillin antibiotics, ampicillin, amoxicillin-clavulanic acid and piperacillin-tazobactam, was 61 (92%), 54 (82%) and 24 (36%) respectively. The isolates were also evaluated for their resistance to the cephalosporins, cefazolin, cefuroxime, ceftazidime, ceftriaxone, cefepime, and ceftolozane-tazobactam; the respective number of resistant isolates were 60 (91%), 60 (91%), 39 (59%), 48 (73%), 42 (64%) and 27(41%). In contrast, a fraction of Ziziphus spina-christi leaves that was extracted using ethyl acetate inhibited all of the carbapenem-resistant isolates studied. The zone of inhibition (ZoI) Ø was between 19 and 24 mm. The ZoI Ø of black deer musk was 11–19 mm. The minimum inhibitory concentration (MICs) of ethyl acetate extract of Ziziphus spina-christi leaves for Acinetobacter baumannii (PDR), CR-Citrobacter farmeri, CR-Escherichia coli, CR-Proteus mirabilis, CR-Pseudomonas fluorescens, CR-Escherichia vulneris, CR-Kluyvera ascorbata, CR-Pantoea agglomerans, CR-Pseudomonas putida and CR-Serratia marcescens, was 6.25 mg/mL. Meanwhile, the MIC for Acinetobacter calcoaceticus–baumannii complex, Citrobacter freundii, Enterobacter cloacae, Klebsiella pneumoniae, Morganella morganii, Pseudomonas aeruginosa and Stenotrophomonas maltophilia was 12.5 mg/mL. High-performance liquid chromatography (HPLC) was used to analyse the components of the ethyl acetate-extract of Ziziphus spina-christi leaves. The analysis found gallic acid (760.3 ppm/mL), caffeine (84.0 ppm/mL) and quercetin (2.2 ppm/mL); the total phenolic content was 846.5 ppm/mL. The evidence obtained from this study indicates that leaves of this plant (named sidr in the Middle East) have the potential to be used as a natural antibiotic against carbapenem-resistant Gram-negative bacteria. Thus, the leaves of this tree present an important opportunity in the development of novel therapeutic agents. The study found the MIC of deer musk for CR-Citrobacter farmeri, CR-Citrobacter freundii, CR-Enterobacter cloacae, CR-Escherichia vulneris, CR-Klebsiella pneumoniae, CR-Kluyvera ascorbata, CR-Morganella morganii, CR-Pantoea agglomerans, CR-Proteus mirabilis, CR-Pseudomonas fluorescens, CR-Pseudomonas putida and CR-Serratia marcescens to be 50 mg/mL. In contrast, the MIC of deer musk was 100 mg/mL for Acinetobacter baumannii (PDR), CR-Acinetobacter calcoaceticus–baumannii complex, CR-Escherichia coli, CR-Pseudomonas aeruginosa and CR-Stenotrophomonas maltophilia. The results of the gas chromatography–mass spectrometry (GC–MS) indicate that the primary constituents of musk were1,4,4-tetramethyltetralin, 7-acetyl-6-ethyl-1, diethyl phthalate and tonalid; their contribution to the whole ranged from 12.2% to 19.6%. Black musk exhibits considerable antibacterial activity, able to inhibit seventeen different species of carbapenem-resistant Gram-negative bacteria. The non-natural form of black musk can be used to scent detergent

Management of Lung Nodules and Lung Cancer Screening During the COVID-19 Pandemic: CHEST Expert Panel Report

BACKGROUND:The risks from potential exposure to coronavirus disease 2019 (COVID-19), and resource reallocation that has occurred to combat the pandemic, have altered the balance of benefits and harms that informed current (pre-COVID-19) guideline recommendations for lung cancer screening and lung nodule evaluation. Consensus statements were developed to guide clinicians managing lung cancer screening programs and patients with lung nodules during the COVID-19 pandemic. METHODS:An expert panel of 24 members, including pulmonologists (n = 17), thoracic radiologists (n = 5), and thoracic surgeons (n = 2), was formed. The panel was provided with an overview of current evidence, summarized by recent guidelines related to lung cancer screening and lung nodule evaluation. The panel was convened by video teleconference to discuss and then vote on statements related to 12 common clinical scenarios. A predefined threshold of 70% of panel members voting agree or strongly agree was used to determine if there was a consensus for each statement. Items that may influence decisions were listed as notes to be considered for each scenario. RESULTS:Twelve statements related to baseline and annual lung cancer screening (n = 2), surveillance of a previously detected lung nodule (n = 5), evaluation of intermediate and high-risk lung nodules (n = 4), and management of clinical stage I non-small cell lung cancer (n = 1) were developed and modified. All 12 statements were confirmed as consensus statements according to the voting results. The consensus statements provide guidance about situations in which it was believed to be appropriate to delay screening, defer surveillance imaging of lung nodules, and minimize nonurgent interventions during the evaluation of lung nodules and stage I non-small cell lung cancer. CONCLUSIONS:There was consensus that during the COVID-19 pandemic, it is appropriate to defer enrollment in lung cancer screening and modify the evaluation of lung nodules due to the added risks from potential exposure and the need for resource reallocation. There are multiple local, regional, and patient-related factors that should be considered when applying these statements to individual patient care

Effects of different dosages of caffeine administration on wrestling performance during a simulated tournament

The aim of the present study was to investigate the effects of different forms of caffeine administration on physical performance during a simulated wrestling tournament. In a double-blind and randomized experiment, twelve male freestyle wrestlers competed in a simulated wrestling tournament (5 wrestling matches consisting of 2×3-min wrestling rounds) following the ingestion of: a placebo, a high-dose of caffeine (10 mg/kg), a moderate-dose caffeine (4 mg/kg), a repeated-dose caffeine (2 mg/kg before each match to a total of 10 mg/kg) or a selective caffeine administration based on performance decrement previously measured (6.16±1.58 mg/kg). The Pittsburgh Wrestling Performance Test (PWPT) was measured before each match to assess physical performance. In comparison to the placebo, the high dose of caffeine only reduced PWPT time before the first match (56.8±2.0 vs. 52.9±1.8 s; p < 0.05). The moderate dose of caffeine did not affect PWPT performance during the tournament. Both, the repeated dose and the selective administration of caffeine reduced PWPT time with respect to the placebo in the third (66.7±1.8 vs. ~63.1±1.4 s; p < 0.05) and fourth matches (72.3±2.4 vs. ~65.9±1.3 s; p < 0.05). However, only the selective dose of caffeine reduced PWPT time before the fifth match (62.7±3.0 vs. 56.3±2.0; p < 0.05). The dosage and administration of caffeine affect the ergogenic effects obtained following the ingestion of this substance. An individualized protocol to provide caffeine when physical performance is expected to be reduced might improve wrestling performance during the latter stages of a tournament

The Role of Chest Imaging in Patient Management During the COVID-19 Pandemic: A Multinational Consensus Statement From the Fleischner Society.

With more than 900,000 confirmed cases worldwide and nearly 50,000 deaths during the first three months of 2020, the COVID-19 pandemic has emerged as an unprecedented healthcare crisis. The spread of COVID-19 has been heterogeneous, resulting in some regions having sporadic transmission and relatively few hospitalized patients with COVID-19 and others having community transmission that has led to overwhelming numbers of severe cases. For these regions, healthcare delivery has been disrupted and compromised by critical resource constraints in diagnostic testing, hospital beds, ventilators, and healthcare workers who have fallen ill to the virus exacerbated by shortages of personal protective equipment. While mild cases mimic common upper respiratory viral infections, respiratory dysfunction becomes the principal source of morbidity and mortality as the disease advances. Thoracic imaging with chest radiography (CXR) and computed tomography (CT) are key tools for pulmonary disease diagnosis and management, but their role in the management of COVID-19 has not been considered within the multivariable context of the severity of respiratory disease, pre-test probability, risk factors for disease progression, and critical resource constraints. To address this deficit, a multidisciplinary panel comprised principally of radiologists and pulmonologists from 10 countries with experience managing COVID-19 patients across a spectrum of healthcare environments evaluated the utility of imaging within three scenarios representing varying risk factors, community conditions, and resource constraints. Fourteen key questions, corresponding to 11 decision points within the three scenarios and three additional clinical situations, were rated by the panel based upon the anticipated value of the information that thoracic imaging would be expected to provide. The results were aggregated, resulting in five main and three additional recommendations intended to guide medical practitioners in the use of CXR and CT in the management of COVID-19

Dorsal Root Ganglia Macrophages Maintain Osteoarthritis Pain

Pain is the major debilitating symptom of osteoarthritis (OA), which is difficult to treat. In OA patients joint tissue damage only poorly associates with pain, indicating other mechanisms contribute to OA pain. Immune cells regulate the sensory system, but little is known about the involvement of immune cells in OA pain. Here, we report that macrophages accumulate in the dorsal root ganglia (DRG) distant from the site of injury in two rodent models of OA. DRG macrophages acquired an M1-like phenotype, and depletion of DRG macrophages resolved OA pain in male and female mice. Sensory neurons innervating the damaged knee joint shape DRG macrophages into an M1-like phenotype. Persisting OA pain, accumulation of DRG macrophages, and programming of DRG macrophages into an M1-like phenotype were independent of Nav1.8 nociceptors. Inhibition of M1-like macrophages in the DRG by intrathecal injection of an IL4-IL10 fusion protein or M2-like macrophages resolved persistent OA pain. In conclusion, these findings reveal a crucial role for macrophages in maintaining OA pain independent of the joint damage and suggest a new direction to treat OA pain. SIGNIFICANCE STATEMENT: In OA patients pain poorly correlates with joint tissue changes indicating mechanisms other than only tissue damage that cause pain in OA. We identified that DRG containing the somata of sensory neurons innervating the damaged knee are infiltrated with macrophages that are shaped into an M1-like phenotype by sensory neurons. We show that these DRG macrophages actively maintain OA pain remotely and independent of joint damage. The phenotype of these macrophages is crucial for a pain-promoting role. Targeting the phenotype of DRG macrophages with either M2-like macrophages or a cytokine fusion protein that skews macrophages into an M2-like phenotype resolves OA pain. Our work reveals a mechanism that contributes to the maintenance of OA pain distant from the affected knee joint and suggests that dorsal root ganglia macrophages are a target to treat osteoarthritis chronic pain