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1.
J Proteome Res ; 23(7): 2367-2375, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38814071

RESUMO

Investigating snake venom is necessary for developing new treatments for envenoming and harnessing the therapeutic potential that lies within venom toxins. Despite considerable efforts in previous research, several technical challenges remain for characterizing the individual components within such complex mixtures. Here, we present native and top-down mass spectrometry (MS) workflows that enable the analysis of individual venom proteins within complex mixtures and showcase the utility of these methodologies on King cobra (Ophiophagus hannah) venom. First, we coupled ion mobility spectrometry for separation and electron capture dissociation for charge reduction to resolve highly convoluted mass spectra containing multiple proteins with masses ranging from 55 to 127 kDa. Next, we performed a top-down glycomic analysis of a 25.5 kDa toxin, showing that this protein contains a fucosylated complex glycan. Finally, temperature-controlled nanoelectrospray mass spectrometry facilitated the top-down sequence analysis of a ß-cardiotoxin, which cannot be fragmented by collisional energy due to its disulfide bond pattern. The work presented here demonstrates the applicability of new and promising MS methods for snake venom analysis.


Assuntos
Venenos Elapídicos , Animais , Venenos Elapídicos/química , Elapidae , Venenos de Serpentes/química , Espectrometria de Mobilidade Iônica/métodos , Espectrometria de Massas/métodos , Proteômica/métodos , Sequência de Aminoácidos
2.
Artigo em Inglês | MEDLINE | ID: mdl-38978283

RESUMO

INTRODUCTION: The QDOT MICROTM Ablation Catheter is a next-generation ablation catheter that allows for high-power ablation up to 90 watts. METHODS: We aimed to assess AE associated with the QDOT MICROTM catheter using the MAUDE database. A MAUDE database search was conducted on May 25, 2024, to capture all AEs (since FDA approval) associated with this ablation catheter. RESULTS: A total of 302 AEs from November 23, 2022, to April 30, 2024, were reported including 148 (49%) catheter-related issues and 154 (51%) clinical complications. Among the catheter-related issues, physical catheter damage (74.3%, n = 110) was most common, followed by communication or display issue (10.8%, n = 16), irrigation issue (9.5%, n = 14), signal issue or artifact (3.4%, n = 5), and inaccurate temperature measurement (2.0%, n = 3). Regarding clinical complications, the most common AE was pericardial effusion (43.5%, n = 67), followed by char formation (11.7%, n = 18), catheter thrombosis (7.1%, n = 11), stroke (7.1%, n = 11), pericarditis (7.1%, n = 11), esophageal complications (6.5%, n = 10), phrenic nerve palsy (3.9%, n = 6), cardiac arrest (3.9%, n = 6), significant AV block (3.9%, n = 6), pulmonary vein stenosis (3.2%, n = 5), coronary artery spasm (1.3%, n = 2), and pulmonary embolism (0.6%, n = 1). There were 11 deaths (five related to esophageal complications, five related to cardiac arrest, and one related to pericardial effusion with cardiac tamponade). CONCLUSION: As high-power ablation strategy with novel ablation catheters is becoming more widely utilized, operators must be aware of potential catheter-related issues and clinical complications that may arise. More data are needed to further evaluate risks of these complications to improve the catheter's safety and efficacy.

3.
J Cardiovasc Electrophysiol ; 35(5): 886-894, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38433316

RESUMO

INTRODUCTION: Through systematic scientific rigor, the CLOSE guided workflow was developed and has been shown to improve pulmonary vein isolation durability. However, this technique was developed at a time when using power-controlled ablation catheters with conventional power ranges was the norm. There has been increased adoption of a high-power and very high-power short-duration ablation practice propelled by the availability of the temperature-controlled radiofrequency QDOT MICRO catheter. METHODS: There are fundamental differences in biophysics between very high-powered temperature guided ablation and conventional ablation strategy that may impact patient outcomes. The catheter's design and ablation modes offer flexibility in technique while accommodating the individual operator's clinical discretion and preference to deliver a durable, transmural, and contiguous lesion set. RESULTS: Here, we provide recommendations for 3 different workflows using the QDOT MICRO catheter in a step-by-step manner for pulmonary vein isolation based on our cumulative experience as early adopters of the technology and the data available in the scientific literature. CONCLUSIONS: With standardization, temperature-controlled ablation with the QDOT MICRO catheter provides operators the flexibility of implementing different ablation strategies to ensure durable contiguous pulmonary vein isolation depending on patient characteristics.


Assuntos
Fibrilação Atrial , Cateteres Cardíacos , Ablação por Cateter , Desenho de Equipamento , Veias Pulmonares , Humanos , Potenciais de Ação , Fibrilação Atrial/cirurgia , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/diagnóstico , Ablação por Cateter/instrumentação , Frequência Cardíaca , Veias Pulmonares/cirurgia , Veias Pulmonares/fisiopatologia , Temperatura , Fatores de Tempo , Resultado do Tratamento , Fluxo de Trabalho
4.
Environ Res ; 256: 119245, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38810821

RESUMO

Microalgae have been renowned as the most promising energy organism with significant potential in carbon fixation. In the large-scale cultivation of microalgae, the 3D porous substrate with higher specific surface area is favorable to microalgae adsorption and biofilm formation, whereas difficult for biofilm detachment and microalgae harvesting. To solve this contradiction, N-isopropylacrylamide, a temperature-responsive gels material, was grafted onto the inner surface of the 3D porous substrate to form temperature-controllable interface wettability. The interfacial free energy between microalgae biofilm and the substrates increased from -63.02 mJ/m2 to -31.89 mJ/m2 when temperature was lowered from 32 °C to 17 °C, weakening the adsorption capacity of cells to the surface, and making the biofilm detachment ratio increased to 50.8%. When further cooling the environmental temperature to 4 °C, the detachment capability of microalgae biofilm kept growing. 91.6% of the cells in the biofilm were harvesting from the 3D porous substrate. And the biofilm detached rate was up to 19.84 g/m2/h, realizing the temperature-controlled microalgae biofilm harvesting. But, microalgae growth results in the secretion of extracellular polymeric substances (EPS), which enhanced biofilm adhesion and made cell detachment more difficult. Thus, ultrasonic vibration was used to reinforce biofilm detachment. With the help of ultrasonic vibration, microalgae biofilm detached rate increased by 143.45% to 41.07 g/m2/h. These findings provide a solid foundation for further development of microalgae biofilm detachment and harvesting technology.


Assuntos
Biofilmes , Géis , Microalgas , Temperatura , Biofilmes/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Porosidade , Géis/química , Acrilamidas/química
5.
Artigo em Inglês | MEDLINE | ID: mdl-39249514

RESUMO

PURPOSE: To evaluate the impact of temperature-controlled pars plana vitrectomy (PPV) on structural and functional outcomes in a rabbit eye model in vivo. METHODS: Ten healthy New Zealand White rabbits underwent temperature-controlled PPV in the right eye (group A), using a device specifically designed to heat the infusion fluid/air and integrated into the vitrectomy machine, and conventional PPV in the left eye (group B). Both eyes received ophthalmic examination and electroretinography (ERG) before and 1 week postoperatively. After 1-week ERG, rabbits were enucleated and then sacrificed. Histological and immunohistochemical examinations were performed on enucleated eyes and expression of glial fibrillary acidic protein (GFAP) and vimentin investigated. RESULTS: Postoperatively, only group B showed significantly decreased amplitude and increased latency of a-wave at 3 cd·s/m2 (p = 0.001 and 0.005, respectively). Significant increase of b-wave latency at 0.01 cd·s/m2 was detected in both groups (p = 0.019 and 0.023, respectively). Postoperatively, amplitude of oscillatory potentials (OPs) increased significantly in group A (p = 0.023) and decreased in group B. In both groups, OPs latency significantly increased at 1-week test (P < 0.05). A greater number of eyes without structural retinal alterations was detected in group A compared to group B (6 vs 5, respectively). GFAP expression was higher in group B than group A, even if the difference was not statistically significant. CONCLUSION: Temperature-controlled PPV resulted in more favorable functional and structural outcomes in rabbit eyes compared with conventional PPV, supporting the potential beneficial role of the intraoperative management of intraocular temperature in vitreoretinal surgery.

6.
Molecules ; 29(8)2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38675526

RESUMO

Herein, a general and practical temperature-controlled approach for the divergent synthesis of pyrazoles and 1-tosyl-1H-pyrazoles via electrophilic cyclization in the absence of transition-metal catalysts and oxidants was developed. The desired products were obtained in moderate to excellent yields from common starting materials in both ionic liquids and ethanol by simply tuning the reaction temperature. This strategy employs easily synthesized substrates, mild reaction conditions, and excellent functional-group tolerance.

7.
Molecules ; 29(5)2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38474597

RESUMO

Rhodium-catalyzed cycloaddition reactions are a powerful tool for the construction of polycyclic compounds. Combined experimental and DFT studies were used to investigate the temperature-controlled chemoselectivity of cationic rhodium-catalyzed intramolecular cycloaddition reactions of ene-vinylidenecyclopropanes. After a series of mechanistic studies, it was found that trace amounts of water in the reaction system play an important role in generating the product with endo double bond located on a five-membered ring and revealed that trace amounts of water in the reaction system, including the rhodium catalyst, substrate and solvent, were sufficient to promote the formation of the product with endo double bond located on a five-membered ring, and additional water could not further accelerate the reaction. DFT calculation results show that the addition of water indeed significantly lowers the energy barrier of the proton transfer step, making the formation of the product with endo double bond located on a five-membered ring more likely to occur and confirming the rationality of water-assisted proton transfer occurring in the selective access to the product with endo double bond located on a five-membered ring.

8.
J Cardiovasc Electrophysiol ; 34(12): 2493-2503, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37870157

RESUMO

INTRODUCTION: The prospective, nonrandomized, multicenter Q-FFICIENCY study demonstrated the safety and 12-month efficacy of paroxysmal atrial fibrillation (AF) ablation with the novel QDOT MICRO temperature-controlled, contact force-sensing, radiofrequency (RF) catheter. Participants underwent pulmonary vein isolation with very high-power short-duration (vHPSD) mode (90 W, ≤4 s) alone or combined with conventional-power temperature-controlled (CPTC) mode (25-50 W). This study aimed to assess quality-of-life (QOL) and healthcare utilization (HCU) benefits experienced by Q-FFICIENCY study participants. METHODS: Besides evaluating procedural efficiency, QOL and HCU were assessed through 12 months postablation via Atrial Fibrillation Effect on Quality-of-Life Tool (AFEQT) score, antiarrhythmic drug (AAD) use, and incidence of cardioversion and cardiovascular hospitalization. RESULTS: Of 191 participants enrolled, 166 were ablated with the new catheter. Compared to baseline, statistically significant, clinically meaningful improvements in composite and subcategories of AFEQT scores were observed at 3 months and sustained through 12 months (12-month increase, 29.3-44.2 points). Class I/III AAD use decreased from 97.6% (162/166) at baseline to 19.6% (31/158) during Months 6-12, representing a significant 79.9% reduction. The cardioversion rate significantly declined by 93.9% from 31.3% (12 months preablation) to 1.9% (evaluation period). One-year Kaplan-Meier estimates of freedom from all-cause and cardiovascular hospitalization were 80.9% (95% confidence interval [CI], 74.8%-86.9%) and 88.8% (95% CI, 84.0%-93.7%), respectively. CONCLUSIONS: Paroxysmal AF ablation with the novel temperature-controlled RF catheter in vHPSD mode, alone or with CPTC mode, led to clinically meaningful improvement in QOL and significant reduction in AAD use, cardioversion, and cardiovascular hospitalization.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Humanos , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Fibrilação Atrial/tratamento farmacológico , Estudos Prospectivos , Qualidade de Vida , Temperatura , Resultado do Tratamento , Catéteres , Antiarrítmicos/uso terapêutico , Veias Pulmonares/cirurgia , Aceitação pelo Paciente de Cuidados de Saúde , Ablação por Cateter/efeitos adversos
9.
Environ Res ; 216(Pt 3): 114645, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36323351

RESUMO

Microalgae biofilm-based culture provides an efficient CO2 reduction and wastewater treatment method for its high photosynthetic efficiency and density. As supporting substrates for microalgae biofilm, porous materials have a big available adsorption area, but mutual shading makes it difficult to transmit external light to the internal surface for attached cells' photosynthesis. Thus, light-guided particles (SiO2) were introduced into photosensitive resin to fabricate a light-guided ordered porous photobioreactor (PBR) by 3D printing technology in this study. The space utilization of the PBR was significantly enhanced and the effective microalgae adsorption area was increased by 13.6 times. Further, a thermo-responsive hydrogel was grafted onto the surface of the substrate to form a smart temperature-controllable interface that could enhance microalgae adsorption and desorption in both directions. When the thermo-responsive layer received light, it would generate heat due to the hydrogel's photo-thermal effect. And the surface temperature would then raise to 33 °C, higher than the hydrogel phase transition point of 32 °C, making the surface shrinking and more hydrophobicity for microalgae cells attachment. The microalgae cells' adsorption capacity increased by 103%, resulting in a high microalgae growth rate of 3.572 g m-2 d-1. When turning off the light, the surface temperature would cool down to below 20 °C, the surface would shrink. And the biofilm shows a 564.7% increase in desorption ability, realizing temperature-controlled microalgae harvesting.


Assuntos
Microalgas , Dióxido de Carbono , Adsorção , Temperatura , Porosidade , Dióxido de Silício , Fotobiorreatores , Biofilmes , Hidrogéis , Biomassa
10.
BMC Womens Health ; 23(1): 121, 2023 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-36959573

RESUMO

OBJECTIVE: Vaginal laxity could negatively influence women's sexual function. This study aimed to explore the efficacy and safety of temperature controlled dual-mode (monopolar and bipolar) radiofrequency (RF) in women with vaginal laxity. METHODS: A total of 102 patients with vaginal laxity were treated with temperature-controlled RF. The present study implemented Vaginal Laxity Questionnaire (VLQ), Female Sexual Function Index (FSFI) questionnaire and Sexual Satisfaction Questionnaire (SSQ) on all patients at baseline and after treatment. Pelvic Organ Prolapse Quantification System (POP-Q) system was applied to physical examination, and vaginal manometer to examine the strength of voluntary contractions of the pelvic floor muscles. RESULTS: The VLQ score was gradually increased after RF treatment at 1, 3, 6 and 12 months, accompanying by the significant improvement in total FSFI scores and the six domains (sexual desire, sexual arousal, lubrication, orgasm, satisfaction, pain). The increased sexual satisfaction based on the SSQ score was found after temperature-controlled RF. The result of POP-Q stage showed significant difference in women after treatment, with the women having Stage I of 45.10% at baseline, 36.27% at 1 month, 28.43% at 3 months, 19.61% at 6 months and 10.78% at 12 months. The mean pressure and mean duration of pelvic contractions were increased gradually at the 1-, 3-, 6- and 12- month follow-up. CONCLUSION: Temperature controlled dual-mode (monopolar and bipolar) radiofrequency may be associated with improvement of vaginal laxity, and contribute to enhancement to female sexual function and pelvic floor muscles.


Assuntos
Libido , Vagina , Feminino , Humanos , Temperatura , Pelve , Inquéritos e Questionários , Resultado do Tratamento
11.
BMC Pulm Med ; 22(1): 407, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36352399

RESUMO

PURPOSE: Uncontrolled severe asthma constitutes a major economic burden to society. Add-ons to standard inhaled treatments include inexpensive oral corticosteroids and expensive biologics. Nocturnal treatment with Temperature-controlled Laminar Airflow (TLA; Airsonett®) could be an effective, safe and cheaper alternative. The potential of TLA in reducing severe asthma exacerbations was addressed in a recent randomised placebo-controlled trial (RCT) in patients with severe asthma (Global Initiative for Asthma (GINA) step 4/5), but the results were inconclusive. We re-analysed the RCT with severe exacerbations stratified by the level of baseline asthma symptoms and Quality of Life. METHODS: More uncontrolled patients, defined by Asthma Control Questionnaire 7 (ACQ7) > 3, EuroQoL 5-Dimension Questionnaire Visual Analogue Scale (EQ5D-VAS) ≤ 65 and Asthma Quality of Life Questionnaire (AQLQ) ≤ 4 were selected for re-analysis. The rates of severe asthma exacerbations, changes in QoL and health-economics were analysed and compared between TLA and placebo. RESULTS: The study population included 226 patients (113 TLA / 113 placebo.) The rates of severe asthma exacerbations were reduced by 33, 31 and 25% (p = 0.083, 0.073, 0.180) for TLA compared to placebo, dependent on selected control measures (ACQ7, EQ5D-VAS, AQLQ, respectively). For patients with less control defined by AQLQ≤4, the difference in mean AQLQ0-12M between TLA and placebo was 0.31, 0.33, 0.26 (p = 0.085, 0.034, 0.150), dependent on selected covariate (AQLQ, EQ5D-VAS, ACQ7, respectively). For patients with poor control defined by ACQ7 > 3, the difference in EQ5D-5 L utility scores between TLA and placebo was significant at 9 and 12 months with a cost-effective ICER. The results from the original study did not demonstrate these differences. CONCLUSION: This post hoc analysis demonstrated an effect of TLA over placebo on severe exacerbations, asthma control and health economics in a subgroup of patients with more symptomatic severe allergic asthma. The results are consistent with the present recommendations for TLA. However, these differences were not demonstrated in the full study. Several explanations for the different outcomes have been outlined, which should be addressed in future studies. FUNDING: NIHR Health Technology Assessment Programme and Portsmouth Hospitals NHS Trust.


Assuntos
Antiasmáticos , Asma , Hipersensibilidade , Humanos , Corticosteroides/uso terapêutico , Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Qualidade de Vida , Temperatura
12.
Int J Mol Sci ; 23(24)2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36555248

RESUMO

This study evaluated the mechanism of temperature-controlled repeated thermal stimulation (TRTS)-mediated neuronal differentiation. We assessed the effect of SP600125, a c-Jun N-terminal kinase (JNK) inhibitor, on neuronal differentiation of rat PC12-P1F1 cells, which can differentiate into neuron-like cells by exposure to TRTS or neurotrophic factors, including bone morphogenetic protein (BMP) 4. We evaluated neuritogenesis by incubating the cells under conditions of TRTS and/or SP600125. Cotreatment with SP600125 significantly enhanced TRTS-mediated neuritogenesis, whereas that with other selective mitogen-activated protein kinase (MAPK) inhibitors did not-e.g., extracellular signal-regulated kinase (ERK)1/2 inhibitor U0126, and p38 MAPK inhibitor SB203580. We tried to clarify the mechanism of SP600125 action by testing the effect of U0126 and the BMP receptor inhibitor LDN193189 on the SP600125-mediated enhancement of intracellular signaling. SP600125-enhanced TRTS-induced neuritogenesis was significantly inhibited by U0126 or LDN193189. Gene expression analysis revealed that TRTS significantly increased ß3-Tubulin, MKK3, and Smad7 gene expressions. Additionally, Smad6 and Smad7 gene expressions were substantially attenuated through SP600125 co-treatment during TRTS. Therefore, SP600125 may partly enhance TRTS-induced neuritogenesis by attenuating the negative feedback loop of BMP signaling. Further investigation of the mechanisms underlying the effect of SP600125 during TRTS-mediated neuritogenesis may contribute to the future development of regenerative neuromedicine.


Assuntos
Butadienos , Crescimento Neuronal , Animais , Ratos , Butadienos/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Células PC12 , Temperatura
13.
J Environ Manage ; 318: 115626, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35777156

RESUMO

In cold and arid areas, variations of ambient temperature not only lead to a large amount of heat loss from anaerobic digestion reactors but also greater challenges in the stable production of biogas. Common temperature-controlled methods of biogas production, such as coal combustion, electric heating, biogas combustion and so on, are expensive and high energy-consuming. Openly, solar energy is economical and suitable for stable biogas production. However, no pilot studies have yet shown the feasibility of controlling the temperature of annual biogas production with solar energy in cold and arid areas. This paper first theoretically analyzed the energy balance between evacuated tube solar collectors and anaerobic reactors. Then a biogas production system was developed in Lanzhou City, China, consisting mainly of a 3 m3 insulated anaerobic reactor and a solar collector with 30 sticks Φ58 × L1800mm evacuated tubes. Annual batch experiments have been carried out to test the feasibility of stable biogas production at a temperature-controlled by solar energy in cold and arid areas. The results show that dry anaerobic digestion with 20% total solid (TS) can start and operate smoothly even under the condition of low solar irradiation for 3-4 consecutive days. The system can run stability by anaerobic digestion at 26 ± 1 °C in winter and spring, by mesophilic (37 ± 1 °C) and thermophilic (52 ± 1 °C) anaerobic digestion in summer and autumn, which implies a highly efficient operation strategy for agricultural and animal husbandry wastes treatment. These theoretical and experimental results provide a scientific basis and engineering reference for the application of biogas production temperature-controlled by solar energy and have important value for the efficient and low-cost anaerobic digestion treatment of agricultural and animal husbandry wastes in cold and arid areas.


Assuntos
Biocombustíveis , Energia Solar , Anaerobiose , Animais , Reatores Biológicos , Estudos de Viabilidade , Metano , Temperatura
14.
Int Heart J ; 63(3): 504-509, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35650152

RESUMO

Pulmonary vein (PV) isolation (PVI) by continuous, transmural and durable lesions is decisive for ensuring long-term freedom from atrial fibrillation (AF). AF ablation requires irrigated tip catheters to reduce thromboembolic complications. This precluded temperature-controlled delivery of radiofrequency (RF) energy.The aim of this study was to evaluate feasibility, acute efficacy, and safety of an irrigated, temperature-controlled ablation catheter [DiamondTemp™ (DT) Medtronic®] for PVI.Consecutive patients with AF underwent PVI using the DT catheter combined with high-power short-duration RF applications. Ablation settings were (1) a catheter tip temperature limit of 60°C, (2) a temperature-controlled power of 50 W, and (3) application duration of 10 seconds. The primary endpoint was acute isolation of PVs, reassessed after a 30-minute waiting period. Secondary endpoints included procedural parameters (defined as a catheter tip temperature of 50°C > 3 seconds, an impedance drop of 5-10 Ω) and the occurrence of serious adverse events.Fifty consecutive patients [mean age 66 ± 12 years, 38 (76%) women, 24 patients with paroxysmal AF (48%)] were included. Median procedure and left atrial dwell time was 89 [68; 107] and 63 [52; 79] minutes, respectively. Mean number of RF applications was 59 ± 20, and mean total RF duration was 14 ± 6 minutes. Acute PVI was achieved in all patients solely using DT ablation. Acute PV reconnection within the waiting period occurred in five patients; all reconnected PVs were successfully reisolated. One major complication occurred.In this study, the DT ablation system demonstrated high acute efficacy for PVI. Temperature-controlled ablation in conjunction with high-power short-duration applications might be effectively supported.


Assuntos
Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Idoso , Fibrilação Atrial/cirurgia , Ablação por Cateter/métodos , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Veias Pulmonares/cirurgia , Resultado do Tratamento
15.
NMR Biomed ; 34(6): e4494, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33586271

RESUMO

MRI phantom studies often fail to mimic the temperature of the human body, which can negatively impact accuracy. An artifact induced by increasing temperature in liquid phantoms was observed, presenting a significant challenge to temperature-controlled experiments. In this study we characterize and provide a solution to eliminate this temperature-induced MRI artifact. Low concentration (0.5-2.5 mM) agar phantoms were prepared. Utilizing a temperature-controlled phantom holder, T1 - and T2 -weighted structural images were acquired at 7 T along with quantitative B0 , B1 , T1 , T2 and ADC maps at both 25 and 37°C. Additionally, computer simulations were conducted to demonstrate the fluid flow and thermal flux patterns in water to provide an insight into the origins of the artifact. Evidence from computer simulation and quantitative MRI strongly suggest the artifact was caused by heat transfer in the form of natural convection leading to structured patterns of signal loss in MR images. The artifact was present up to agar concentrations of 1.5 mM (T1 = 3068 ± 16 ms, T2 = 1052 ± 20 ms, ADC = 2.29 ± 0.36 × 10-3 mm2 /s at 25°C; T1 = 3928 ± 44 ms, T2 = 1122 ± 24 ms, ADC = 2.64 ± 0.49 × 10-3 mm2 /s at 37°C), above which point increased sample viscosity no longer allows for convection currents, thereby eliminating the artifact. The methodology described in this work simplifies quantitative MR acquisition of liquid phantoms at physiological temperature by suppressing convection currents with relatively small changes to intrinsic MR parameters (T1 increased by 1.4% and T2 decreased by 17% for 1.5 mM agar at 25°C).


Assuntos
Artefatos , Convecção , Imageamento por Ressonância Magnética , Imagens de Fantasmas , Temperatura , Simulação por Computador , Difusão
16.
Lasers Surg Med ; 53(3): 370-376, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32644221

RESUMO

BACKGROUND AND OBJECTIVES: Temperature-controlled radiofrequency inferior turbinate ablation (TCRFA) uses a feedback system to control thermal injury and achieve precise volumetric heating to induce specific scar formation. However, it requires costly single-use proprietary consumables. Comparable volumetric tissue heating may be achieved for a fraction of the cost by adjusting the power settings on traditional monopolar electrosurgery devices that use low-cost needle tips. This pre-clinical study aims to determine the optimized power parameters to achieve electrosurgical coagulum volume similar to that of TCRFA. STUDY DESIGN/MATERIALS AND METHODS: An electrosurgery submucosal diathermy (SMD) system (cut mode, 4-32 W, 5-120 seconds) and a temperature-controlled radiofrequency ablation system (standard clinical parameters for treating inferior turbinate hypertrophy) were used to coagulate egg white and chicken breast. Coagulum major and minor axis were measured, and lesion volume was approximated as prolate spheroid. RESULTS: No significant difference in volume was found between the temperature-controlled system and the electrosurgery system at 8 W for 30 seconds, 8 W for 60 seconds, 16 W for 30 seconds, 32 W for 5 seconds, and 32 W for 15 seconds. The time to achieve equivalent lesion size was significantly less in the SMD system when compared to the temperature-controlled system (P < 0.05). CONCLUSION: Electrosurgery handpieces may achieve similar lesion volume effects as the temperature feedback-controlled, single-use handpieces when set to the optimized parameters. SMD handpieces are significantly more cost and time effective than proprietary devices, and they are easily used in the office. SMD devices may be a more affordable alternative to temperature-controlled systems with comparable lesion volume effect and may be valuable for office-based therapy. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.


Assuntos
Ablação por Cateter , Diatermia , Eletrocirurgia , Retroalimentação , Calefação , Conchas Nasais/cirurgia
17.
Nano Lett ; 20(3): 2137-2143, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32048853

RESUMO

Photothermal therapy (PTT) is an effective approach to cancer therapy. However, the high temperature during the therapy increases the damage to surrounding normal tissues. Thermochromic material, which exhibits temperature-activated color change and optical absorption, is a promising photothermal agent for precisely temperature-controlled PTT. Nevertheless, the construction of nanosized thermochromic particles with an appropriate transition temperature (44-47 °C) is still a great challenge. Here, thermochromic nanoparticles with the transition temperature at 45 °C based on a leuco dye-developer-solvent system are developed for thermostatic photothermal tumor therapy. Below the temperature, the nanoparticles take a dark green color to absorb light and convert it into heat efficiently. Once the temperature reaches the transition point, the colored nanoparticles switch to a colorless state, maintaining the temperature at the predefined level and allowing deeper light penetration. The autoregulated nanoparticles exhibit a prominent therapeutic effect for the tumor without destroying normal tissues.


Assuntos
Nanopartículas , Neoplasias Experimentais/terapia , Terapia Fototérmica , Animais , Humanos , Células MCF-7 , Camundongos , Nanopartículas/química , Nanopartículas/uso terapêutico , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
18.
J Sci Food Agric ; 101(6): 2371-2379, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33009832

RESUMO

BACKGROUND: Chinese horsebean-chili-paste (CHCP) is a traditional fermented condiment in China, known as 'the soul of Sichuan cuisine'. The horsebean-to-meju phase in its preparation is important for CHCP production and contributes significantly to its taste and odor. In this study, a comprehensive flavor compound profiling analysis of the naturally brewed horsebean meju (NBHM) and the temperature-controlled brewed horsebean meju (TCBHM) was performed with two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS), and the analysis of physicochemical characteristics and free amino acids. Their aroma-active components and characteristic flavor compounds were evaluated. The flavor compounds responsible for differentiating NBHM and TCBHM were also determined based on the Fisher ratio and principal component analysis. RESULTS: The pH and the reducing sugar and amino-acid nitrogen content of NBHM were 5.38, 64.43, and 5.76 g kg-1 , respectively, whereas those of TCBHM were 5.13, 29.20, and 7.43 g kg-1 . A total of 356 volatiles were identified from 2571 compounds, and 257 volatile compounds were identified in NBHM compared to 322 volatiles in TCBHM. These two horsebean mejus (HMs) exhibited a similar proportion profile for 30 aroma-active compounds. Benzoic acid ethyl ester, 4-ethyl-2-methoxy-phenol and argnine were determined to be characteristic flavor components for NBHM, while 1-(2-furanyl)-ethanone, 2,6-dimethyl-pyrazine, threonine, valine and tyrosine were specific to TCBHM. CONCLUSION: Temperature-controlled brewed horsebean meju possessed better physicochemical and flavor characteristics than NBHM. The temperature-controlled brewing technique in CHCP production can be used as a promising alternative to the traditional natural brewing method. © 2020 Society of Chemical Industry.


Assuntos
Manipulação de Alimentos/métodos , Vicia faba/química , China , Condimentos/análise , Fermentação , Alimentos Fermentados/análise , Aromatizantes/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Odorantes/análise , Sementes/química , Paladar , Temperatura
19.
Angew Chem Int Ed Engl ; 60(28): 15390-15398, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33822450

RESUMO

Quadruplexes are non-canonical nucleic acid structures essential for many cellular processes. Hybrid quadruplex-duplex oligonucleotide assemblies comprised of multiple domains are challenging to study with conventional biophysical methods due to their structural complexity. Here, we introduce a novel method based on native mass spectrometry (MS) coupled with a custom-built temperature-controlled nanoelectrospray ionization (TCnESI) source designed to investigate interactions between proximal DNA domains. Thermal denaturation experiments were aimed to study unfolding of multi-stranded oligonucleotide constructs derived from biologically relevant structures and to identify unfolding intermediates. Using the TCnESI MS, we observed changes in Tm and thermodynamic characteristics of proximal DNA domains depending on the number of domains, their position, and order in a single experiment.

20.
Bioessays ; 40(7): e1700216, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29869389

RESUMO

The circadian clock is a cell autonomous oscillator that controls many aspects of physiology through generating rhythmic gene expression in a time of day dependent manner. In addition, in endothermic mammals body temperature cycles contribute to rhythmic gene expression. These body temperature-controlled rhythms are hard to distinguish from classic circadian rhythms if analyzed in vivo in endothermic organisms. However, they do not fulfill all criteria of being circadian if analyzed in cell culture or in conditions where body temperature of an endothermic organism can be manipulated. Here we review and compare these characteristics, discuss the core clock independent mechanism of temperature-controlled alternative splicing and highlight the requirement of double-checking rhythms that appear circadian within an endothermic organism in a system that allows temperature manipulation.


Assuntos
Relógios Circadianos/genética , Ritmo Circadiano/genética , Mamíferos/crescimento & desenvolvimento , Processamento Alternativo/genética , Animais , Expressão Gênica/genética , Mamíferos/genética , Temperatura
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