scholarly journals A novel therapeutic strategy of multimodal nanoconjugates for state-of-the-art brain tumor phototherapy

2022 ◽  
Vol 20 (1) ◽  
Author(s):  
Hyung Shik Kim ◽  
Minwook Seo ◽  
Tae-Eun Park ◽  
Dong Yun Lee
Keyword(s):  
Oral Administration ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Oral Absorption ◽  
High Heat ◽  
Ros Generation ◽  
Photoconversion Efficiency ◽  
Mice Model ◽  
Maximum Heat ◽  
Aunp Surface

Abstract Background The outcome of phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) for glioblastoma multiforme (GBM), is disappointing due to insufficient photoconversion efficiency and low targeting rate. The development of phototherapeutic agents that target GBM and generate high heat and potent ROS is important to overcome the weak anti-tumor effect. Results In this study, nanoconjugates composed of gold nanoparticles (AuNPs) and photosensitizers (PSs) were prepared by disulfide conjugation between Chlorin e6 (Ce6) and glutathione coated-AuNP. The maximum heat dissipation of the nanoconjugate was 64.5 ± 4.5 °C. Moreover, the proximate conjugation of Ce6 on the AuNP surface resulted in plasmonic crossover between Ce6 and AuNP. This improves the intrinsic ROS generating capability of Ce6 by 1.6-fold compared to that of unmodified-Ce6. This process is called generation of metal-enhanced reactive oxygen species (MERos). PEGylated-lactoferrin (Lf-PEG) was incorporated onto the AuNP surface for both oral absorption and GBM targeting of the nanoconjugate (denoted as Ce6-AuNP-Lf). In this study, we explored the mechanism by which Ce6-AuNP-Lf interacts with LfR at the intestinal and blood brain barrier (BBB) and penetrates these barriers with high efficiency. In the orthotopic GBM mice model, the oral bioavailability and GBM targeting amount of Ce6-AuNP-Lf significantly improved to 7.3 ± 1.2% and 11.8 ± 2.1 μg/kg, respectively. The order of laser irradiation, such as applying PDT first and then PTT, was significant for the treatment outcome due to the plasmonic advantages provided by AuNPs to enhance ROS generation capability. As a result, GBM-phototherapy after oral administration of Ce6-AuNP-Lf exhibited an outstanding anti-tumor effect due to GBM targeting and enhanced photoconversion efficiency. Conclusions The designed nanoconjugates greatly improved ROS generation by plasmonic crossover between AuNPs and Ce6, enabling sufficient PDT for GBM as well as PTT. In addition, efficient GBM targeting through oral administration was possible by conjugating Lf to the nanoconjugate. These results suggest that Ce6-AuNP-Lf is a potent GBM phototherapeutic nanoconjugate that can be orally administered. Graphical Abstract

scholarly journals Investigation of Heat Management in High Thermal Density Communication Cabinet by a Rear Door Liquid Cooling System

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4385
Author(s):  
Wansheng Yang ◽  
Lin Yang ◽  
Junjie Ou ◽  
Zhongqi Lin ◽  
Xudong Zhao
Keyword(s):  
Data Center ◽  
Heat Dissipation ◽  
Cooling System ◽  
Operating Temperature ◽  
High Heat ◽  
Transformer Oil ◽  
Cooling Efficiency ◽  
Domestic Water ◽  
Maximum Heat ◽  
Rear Door

In this paper, a rear door oil-cooling heat exchanger for data center cabinet-level cooling has been proposed. In order to solve the heat dissipation problem of high heat density data center, this paper applied the mature transformer oil cooling technology to the data room. The heat dissipation of liquid-cooled cabinets and traditional air-cooled cabinets was compared, and the heat dissipation performance of the oil-cooled system was theoretically and experimentally investigated. To investigate the heat dissipation system, the cabinet operating temperature, circulating oil system temperature and cabinet exhaust temperature, cabinet heat density, oil flow rates and fan power were analyzed. It was found that the average cooling efficiency of the liquid-cooled cabinet increased by 66% compared with the average cooling efficiency of the conventional air-cooled cabinet. The operating temperature in air-cooled cabinets is as high as 55 °C, and the operating temperature in liquid-cooled cabinets does not exceed 50 °C. Among which, the maximum heat dissipation efficiency of the liquid-cooled cabinets can reach 58.8%. The oil temperature could reach 46.9 °C after heat exchange, and the exhaust air of the cabinet could reach 42.8 °C, which could be used to prepare domestic water and regenerative desiccant. The results from established calculation model agreed well with the testing results and the model could be used to predict the heat dissipation law of the oil cooling system under different conditions. The research has proposed the potential application of the oil-cooled in cabinet-level cooling, which can help realize saving primary energy and reducing carbon emission.

Enhanced Pool Boiling With HFE7000 Over Selectively Sintered Microchannels

2017 ◽  
Author(s):  
Travis S. Emery ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Pool Boiling ◽  
Electronics Cooling ◽  
Fold Increase ◽  
High Heat ◽  
Heat Fluxes ◽  
Dielectric Fluid ◽  
Maximum Heat ◽  
Maximum Heat Transfer

As the need for efficient thermal management grows, pool boiling’s ability to dissipate high heat fluxes has gained significant interest. The objective of this work was to study the performance of pool boiling at atmospheric pressure using a dielectric fluid, HFE7000. Both plain and enhanced copper surfaces were tested, and these results were then compared to similar testing performed with water and FC-87. The enhanced surfaces utilized microchannels with porous coatings selectively located on different regions of the heat transfer surface. A maximum critical heat flux (CHF) of 41.7 W/cm2 was achieved here, which translated to a 29% CHF increase in comparison to a plain chip. A maximum heat transfer coefficient (HTC) of 104.0 kW/m2°C was also achieved, which translated to a 6-fold increase in HTC when compared to a plain copper chip. More notably, this HTC was achieved at a wall temperature of 38.4 °C. This HTC enhancement was greater than that of water and FC-87 when using the same enhanced surface. The effect of sintering location was found to have a similar effect on CHF with HFE7000 in comparison with water. The effect of microchannel size was shown to have similar effects on CHF when compared with FC-87 and water. From the results found here, it is concluded that the employment of selectively sintered open microchannels with HFE7000 has significant potential for enhanced heat dissipation in electronics cooling applications.

The Length of Disulfide Bond-Containing Linkages Impacts the Oral Absorption and Antitumor Activity of Paclitaxel Prodrugs-Loaded Nanoemulsions

Nanoscale ◽  
2021 ◽  
Author(s):  
Yanlin Gao ◽  
Shiyi Zuo ◽  
Lingxiao Li ◽  
Tian Liu ◽  
Fudan Dong ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Oral Administration ◽  
Disulfide Bond ◽  
Rational Design ◽  
Oral Absorption ◽  
Oral Paclitaxel

Rational design of oral paclitaxel (PTX) preparations is still a challenge. Many studies focus on developing PTX-loaded nanoemulsions (NEs) for oral administration. Unfortunately, PTX has poor affinity with the commonly...

Lack of influence of the antidopaminergic drug domperidone on basal and TRH-stimulated TSH-serum levels after oral administration

1982 ◽  
Vol 101 (4) ◽  
pp. 550-554 ◽  
Author(s):  
K. W. Wenzel ◽  
J. Döring
Keyword(s):  
Oral Administration ◽  
Thyroid Function ◽  
Oral Absorption ◽  
Statistical Significance ◽  
Oral Intake ◽  
Serum Levels ◽  
The Novel ◽  
Antiemetic Drug ◽  
First Pass ◽  
The Difference

Abstract. Since antidopaminergic drugs are known to elevate basal and TRH-stimulated TSH-serum levels and since this effect was also shown after iv administration of the novel dopamine antagonistic agent domperidone, it was investigated, whether this antiemetic drug could interfere after oral intake with the evaluation of thyroid function. Oral domperidone caused a marked TSH-enhancement of TRH-induced TSH increments in 6 out of 14 euthyroid subjects, with no statistical significance, however. The difference between oral and parenteral influence as well as inter-individual changes are probably due to the varying first pass effect of the drug after oral absorption.

Heat dissipation system based on electromagnetic driven rotational flow of liquid metal coolant

2021 ◽  
pp. 1-14
Author(s):  
Lei Wang ◽  
Xudong Zhang ◽  
Dr. Jing Liu ◽  
Yixin Zhou
Keyword(s):  
Liquid Metal ◽  
Thermal Resistance ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Cooling System ◽  
Electric Heater ◽  
Power Relationship ◽  
Rotational Flow ◽  
Large Power ◽  
Dissipation System

Abstract Liquid metal owns the highest thermal conductivity among all the currently available fluid materials. This property enables it to be a powerful coolant for the thermal management of large power device or high flux chip. In this paper, a high-efficiency heat dissipation system based on the electromagnetic driven rotational flow of liquid metal was demonstrated. The velocity distribution of the liquid metal was theoretically analyzed and numerically simulated. The results showed that the velocity was distributed unevenly along longitudinal section and the maximum velocity appears near the anode. On the temperature distribution profile of the heat dissipation system, the temperature on the electric heater side was much higher than the other regions and the role of the rotated liquid metal was to homogenize the temperature of the system. In addition, the thermal resistance model of the experimental device was established, and several relationships such as thermal resistance-power curve were experimentally measured. The heating power could be determined from the temperature-power relationship graph once the maximum control temperature was given. The heat dissipation method introduced in the paper provides a novel way for fabricating compact chip cooling system.

Abstract 1696: Compound RVX-208 Modulates HDL-C Levels and Function in Non-human Primates and in Early (phase I) Human Trials

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Larbi Krimbou ◽  
Ravi Jahagirdar ◽  
Dana Bailey ◽  
Anouar Hafiane ◽  
Isabelle Ruel ◽  
...  
Keyword(s):  
Oral Administration ◽  
Healthy Volunteers ◽  
Size Distribution ◽  
Cholesterol Efflux ◽  
Oral Absorption ◽  
Therapeutic Potential ◽  
Human Study ◽  
Treated Group ◽  
Atherosclerotic Cardiovascular Disease ◽  
Hdl Function

The novel compound RVX-208 is a small molecule that upregulates the gene expression of apoA-I and raises HDL-C in non-human primates. Here, we examined the effects of oral administration of RVX-208 on serum apoA-I and HDL-C levels , HDL size distribution, and HDL function. African green monkeys received RVX-208 (7.5, 15 and 30 mg/kg; twice daily and 60 mg/kg; once daily) or vehicle control for 28, 42, and 63 days. We report that RVX-208 chronic treatment resulted in a highly significant increase in the average of serum apoA-I and HDL-C levels (57% and 92%, respectively). Interestingly, RVX-208 treatment modified the distribution of HDL particle size causing a significant increase in preβ1-LpA-I and larger α1-LpA-I species. The ability of serum to promote cholesterol efflux via ABCA1, ABCG1 or SR-BI-dependent pathways in a cell culture model was significantly increased by RVX-208. The phase Ia safety and pharmacokinetic human study comprised of a total of 80 subjects. In the multiple ascending dose arm, 24 participants were randomly assigned to 3 cohorts of 8 healthy volunteers (6 active and 2 placebo), and received oral administration of RVX-208 at 2, 3 and 8 mg/kg per day or placebo for 7 days. The compound was well tolerated and had good oral absorption meeting the objectives of safety and pharmacokinetics. ApoA-I, HDL-C, HDL size distribution and ABCA1-dependent cholesterol efflux were assessed at days 1 (predose) and 7. The percent change from baseline to day 7 for apoA-I was 11% higher (P = 0.03) in the RVX-208 treated participants compared to placebo. Interestingly, preβ1-LpA-I change was 30% (P = 0.02) higher in the actively treated group and was found to strongly correlate with increased apoA-I levels (R2 = 0.72). Furthermore, ABCA1-dependent cholesterol efflux change was 10% higher (P = 0.03) and was found to correlate with increased preβ1-LpA-I . Taken together, these pharmacodynamic data from human healthy volunteers show consistent trends in apoA-I production and HDL functionality, supporting the findings in the African green monkey. Further investigation of the effect of RVX-208 on the HDL metabolic pathway is ongoing in humans and animals to establish the mechanisms of action and therapeutic potential in treating atherosclerotic cardiovascular disease.

Heat Transfer Enhancement in Compact Phase Change Microchannel Heat Exchangers for High Flux Laser Diodes

2018 ◽  
Author(s):  
Jensen Hoke ◽  
Todd Bandhauer ◽  
Jack Kotovsky ◽  
Julie Hamilton ◽  
Paul Fontejon
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Phase Change ◽  
Flow Boiling ◽  
Laser Diodes ◽  
High Heat ◽  
Heat Fluxes ◽  
High Heat Flux ◽  
Maximum Heat ◽  
Average Maximum

Liquid-vapor phase change heat transfer in microchannels offers a number of significant advantages for thermal management of high heat flux laser diodes, including reduced flow rates and near constant temperature heat rejection. Modern laser diode bars can produce waste heat loads >1 kW cm−2, and prior studies show that microchannel flow boiling heat transfer at these heat fluxes is possible in very compact heat exchanger geometries. This paper describes further performance improvements through area enhancement of microchannels using a pyramid etching scheme that increases heat transfer area by ∼40% over straight walled channels, which works to promote heat spreading and suppress dry-out phenomenon when exposed to high heat fluxes. The device is constructed from a reactive ion etched silicon wafer bonded to borosilicate to allow flow visualization. The silicon layer is etched to contain an inlet and outlet manifold and a plurality of 40μm wide, 200μm deep, 2mm long channels separated by 40μm wide fins. 15μm wide 150μm long restrictions are placed at the inlet of each channel to promote uniform flow rate in each channel as well as flow stability in each channel. In the area enhanced parts either a 3μm or 6μm sawtooth pattern was etched vertically into the walls, which were also scalloped along the flow path with the a 3μm periodicity. The experimental results showed that the 6μm area-enhanced device increased the average maximum heat flux at the heater to 1.26 kW cm2 using R134a, which compares favorably to a maximum of 0.95 kw cm2 dissipated by the plain walled test section. The 3μm area enhanced test sections, which dissipated a maximum of 1.02 kW cm2 showed only a modest increase in performance over the plain walled test sections. Both area enhancement schemes delayed the onset of critical heat flux to higher heat inputs.

Experimental Investigation of a Thermosyphon With Microstructure on the Boiling Surface

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Y. Chai ◽  
W. Tian ◽  
J. Tian ◽  
L. W. Jin ◽  
X. Z. Meng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Pool Boiling ◽  
High Heat ◽  
Primary Concern ◽  
Heat Transfer Efficiency ◽  
Heater Wall ◽  
Micro Structures ◽  
Thermal Physical Properties ◽  
Graphite Foam

Abstract In recent years, a primary concern in the development of electronic technology is high heat dissipation of power devices. The advantages of unique thermal physical properties of graphite foam raise up the possibility of developing pool boiling system with better heat transfer efficiency. A compact thermosyphon was developed with graphite foam insertions to explore how different parameters affect boiling performance. Heater wall temperature, superheat, departure frequency of bubbles, and thermal resistance of the system were analyzed. The results indicated that the boiling performance is affected significantly by thermal conductivity and pore diameter of graphite foam. A proposed heat transfer empirical correlation reflecting the relations between graphite foam micro structures and pool boiling performance of Novec7100 was developed in this paper.

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