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1.
Ann Palliat Med ; 10(3): 2530-2539, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33548991

RESUMO

BACKGROUND: Hypoxaemia in post-surgical patients of esophageal cancer (EC) is common in thoracic departments. However, few studies have investigated the role of high-flow nasal cannula (HFNC) compared with conventional oxygen therapy (COT). METHODS: A retrospective study was implemented to enroll hypoxemic patients after esophagectomy who were treated by HFNC or COT immediately after extubation between January 2019 and December 2019. We compared the effect of HFNC or COT in patients regarding the vital signs and arterial blood gases, the incidence of anastomotic leakage, postoperative pulmonary complications (PPCs), sore throat/nose, and reintubation, length of stay, and sputum production. We also 3D reconstructed the postoperative chest CT, and compared the amount of lung volume loss caused by PPCs (pneumothorax, atelectasis, pulmonary consolidation and pleural effusion) between the two groups. RESULTS: Compared to patients in COT group, sore throat/nose in HFNC group was lower, the sputum production was higher, and the total hospital stay was shorter. Compared to COT, HFNC treatment decreased systolic blood pressure (SBP) at day 1, diastolic blood pressure (DBP) at day 1-4, and heart rate (HR) at day 2-4, increased arterial partial pressure of oxygen (PaO2) at day 1-4, and arterial oxygen saturation (SaO2%) at day 1-2. In addition, the rate of PPCs and anastomotic leakage in HFNC group were lower than those in COT group. Compared to COT, HFNC treatment significantly decreased the amount of lung volume loss caused by PPCs. CONCLUSIONS: HFNC can improve the hypoxemia of patients after esophagectomy, increase the flow of sputum, reduce the incidence of PPC and anastomotic leakage.


Assuntos
Cânula , Neoplasias Esofágicas , Neoplasias Esofágicas/terapia , Humanos , Oxigênio , Oxigenoterapia , Estudos Retrospectivos
2.
ACS Appl Mater Interfaces ; 10(30): 25819-25829, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29972022

RESUMO

Singlet oxygen is a potent agent for the selective killing of a wide range of harmful cells; however, current delivery methods pose significant obstacles to its widespread use as a treatment agent. Limitations include the need for photosensitizer proximity to tissue because of the short (3.5 µs) lifetime of singlet oxygen in contact with water; the strong optical absorption of the photosensitizer, which limits the penetration depth; and hypoxic environments that restrict the concentration of available oxygen. In this article, we describe a novel superhydrophobic singlet oxygen delivery device for the selective inactivation of bacterial biofilms. The device addresses the current limitations by: immobilizing photosensitizer molecules onto inert silica particles; embedding the photosensitizer-containing particles into the plastron (i.e. the fluid-free space within a superhydrophobic surface between the solid substrate and fluid layer); distributing the particles along an optically transparent substrate such that they can be uniformly illuminated; enabling the penetration of oxygen via the contiguous vapor space defined by the plastron; and stabilizing the superhydrophobic state while avoiding the direct contact of the sensitizer to biomaterials. In this way, singlet oxygen generated on the sensitizer-containing particles can diffuse across the plastron and kill bacteria even deep within the hypoxic periodontal pockets. For the first time, we demonstrate complete biofilm inactivation (>5 log killing) of Porphyromonas gingivalis, a bacterium implicated in periodontal disease using the superhydrophobic singlet oxygen delivery device. The biofilms were cultured on hydroxyapatite disks and exposed to active and control surfaces to assess the killing efficiency as monitored by colony counting and confocal microscopy. Two sensitizer particle types, a silicon phthalocyanine sol-gel and a chlorin e6 derivative covalently bound to fluorinated silica, were evaluated; the biofilm killing efficiency was found to correlate with the amount of singlet oxygen detected in separate trapping studies. Finally, we discuss the applications of such devices in the treatment of periodontitis.


Assuntos
Biofilmes , Oxigênio , Fotoquimioterapia , Fármacos Fotossensibilizantes , Dióxido de Silício , Oxigênio Singlete
3.
ACS Appl Mater Interfaces ; 8(17): 10788-99, 2016 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-27070413

RESUMO

Precise dispensing of nanoliter droplets is necessary for the development of sensitive and accurate assays, especially when the availability of the source solution is limited. Conventional approaches are limited by imprecise positioning, large shear forces, surface tension effects, and high costs. To address the need for precise and economical dispensing of nanoliter volumes, we developed a new approach where the dispensed volume is dependent on the size and shape of defined surface features, thus freeing the dispensing process from pumps and fine-gauge needles requiring accurate positioning. The surface we fabricated, called a nanoliter droplet virtual well microplate (nVWP), achieves high-precision dispensing (better than ±0.5 nL or ±1.6% at 32 nL) of 20-40 nL droplets using a small source drop (3-10 µL) on isolated hydrophilic glass pedestals (500 µm on a side) bonded to arrays of polydimethylsiloxane conical posts. The sharp 90° edge of the glass pedestal pins the solid-liquid-vapor triple contact line (TCL), averting the wetting of the glass sidewalls while the fluid is prevented from receding from the edge. This edge creates a sufficiently large energy barrier such that microliter water droplets can be poised on the glass pedestals, exhibiting contact angles greater >150°. This approach relieves the stringent mechanical alignment tolerances required for conventional dispensing techniques, shifting the control of dispensed volume to the area circumscribed by the glass edge. The effects of glass surface chemistry and dispense velocity on droplet volume were studied using optical microscopy and high-speed video. Functionalization of the glass pedestal surface enabled the selective adsorption of specific peptides and proteins from synthetic and natural biomolecule mixtures, such as venom. We further demonstrate how the nVWP dispensing platform can be used for a variety of assays, including sensitive detection of proteins and peptides by fluorescence microscopy or MALDI-TOF.


Assuntos
Nanoestruturas , Vidro , Interações Hidrofóbicas e Hidrofílicas , Proteínas , Molhabilidade
4.
ACS Appl Mater Interfaces ; 7(42): 23575-88, 2015 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-26372672

RESUMO

Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic-hydrophilic surface. An array of hydrophilic needles, thermally connected to a heat sink, was forced through a robust superhydrophobic polymer film. Condensation occurs preferentially on the needle surface due to differences in wettability and temperature. As the droplet grows, the liquid drop on the needle remains in the Cassie state and does not wet the underlying superhydrophobic surface. The water collection rate on this surface was studied using different surface tilt angles, needle array pitch values, and needle heights. Water condensation rates on the hybrid surface were shown to be 4 times greater than for a planar copper surface and twice as large for silanized silicon or superhydrophobic surfaces without hydrophilic features. A convection-conduction heat transfer model was developed; predicted water condensation rates were in good agreement with experimental observations. This type of hybrid superhydrophobic-hydrophilic surface with a larger array of needles is low-cost, robust, and scalable and so could be used for heat transfer and water collection applications.

5.
ACS Appl Mater Interfaces ; 7(4): 2632-40, 2015 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-25525836

RESUMO

Maintaining the long-term stability of superhydrophobic surfaces is challenging because of contamination from organic molecules and proteins that render the surface hydrophilic. Reactive oxygen species generated on a photocatalyst, such as TiO2, could mitigate this effect by oxidizing these contaminants. However, incorporation of such catalyst particles into a superhydrophobic surface is challenging because the particles become hydrophilic under UV exposure, causing the surface to transition to the Wenzel state. Here we show that a high concentration of hydrophilic TiO2 catalytic nanoparticles can be incorporated into a superhydrophobic surface by partially embedding the particles into a printed array of high aspect ratio polydimethylsiloxane posts. A stable Cassie state was maintained on these surfaces, even under UV irradiation, because of the significant degree of hierarchical roughness. By printing the surface on a porous support, oxygen could be flowed through the plastron, resulting in higher photooxidation rates relative to a static ambient. Rhodamine B and bovine serum albumin were photooxidized both in solution and after drying onto these TiO2-containing surfaces, and the effects of particle location and plastron gas composition were studied in static and flowing gas environments. This approach may prove useful for water purification, medical devices, and other applications where Cassie stability is required in the presence of organic compounds.

6.
J Phys Chem A ; 118(45): 10364-71, 2014 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-24885074

RESUMO

We describe physical-organic studies of singlet oxygen generation and transport into an aqueous solution supported on superhydrophobic surfaces on which silicon-phthalocyanine (Pc) particles are immobilized. Singlet oxygen ((1)O2) was trapped by a water-soluble anthracene compound and monitored in situ using a UV-vis spectrometer. When oxygen flows through the porous superhydrophobic surface, singlet oxygen generated in the plastron (i.e., the gas layer beneath the liquid) is transported into the solution within gas bubbles, thereby increasing the liquid-gas surface area over which singlet oxygen can be trapped. Higher photooxidation rates were achieved in flowing oxygen, as compared to when the gas in the plastron was static. Superhydrophobic surfaces were also synthesized so that the Pc particles were located in contact with, or isolated from, the aqueous solution to evaluate the relative effectiveness of singlet oxygen generated in solution and the gas phase, respectively; singlet oxygen generated on particles wetted by the solution was trapped more efficiently than singlet oxygen generated in the plastron, even in the presence of flowing oxygen gas. A mechanism is proposed that explains how Pc particle wetting, plastron gas composition and flow rate as well as gas saturation of the aqueous solution affect singlet oxygen trapping efficiency. These stable superhydrophobic surfaces, which can physically isolate the photosensitizer particles from the solution may be of practical importance for delivering singlet oxygen for water purification and medical devices.


Assuntos
Gases/química , Oxigênio Singlete/química , Antracenos/química , Dimetilpolisiloxanos/química , Indóis/química , Microscopia Eletroquímica de Varredura , Nitrogênio/química , Nylons/química , Processos Fotoquímicos , Polimetil Metacrilato/química , Porosidade , Impressão/métodos , Compostos de Silício/química , Análise Espectral , Água/química , Molhabilidade
7.
J Am Chem Soc ; 135(50): 18990-8, 2013 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-24295210

RESUMO

We describe here a physical-organic study of the first triphasic superhydrophobic sensitizer for photooxidations in water droplets. Control of synthetic parameters enables the mechanistic study of "borderline" two- and three-phase superhydrophobic sensitizer surfaces where (1)O2 is generated in compartments that are wetted, partially wetted, or remain dry in the plastron (i.e., air layer beneath the droplet). The superhydrophobic surface is synthesized by partially embedding silicon phthalocyanine (Pc) sensitizing particles to specific locations on polydimethylsiloxane (PDMS) posts printed in a square array (1 mm tall posts on 0.5 mm pitch). In the presence of red light and oxygen, singlet oxygen is formed on the superhydrophobic surface and reacts with 9,10-anthracene dipropionate dianion (1) within a freestanding water droplet to produce an endoperoxide in 54-72% yields. Control of the (1)O2 chemistry was achieved by the synthesis of superhydrophobic surfaces enriched with Pc particles either at the PDMS end-tips or at PDMS post bases. Much of the (1)O2 that reacts with anthracene 1 in the droplets was generated by the sensitizer "wetted" at the Pc particle/water droplet interface and gave the highest endoperoxide yields. About 20% of the (1)O2 can be introduced into the droplet from the plastron. The results indicate that the superhydrophobic sensitizer surface offers a unique system to study (1)O2 transfer routes where a balance of gas and liquid contributions of (1)O2 is tunable within the same superhydrophobic surface.


Assuntos
Oxigênio/química , Fármacos Fotossensibilizantes/química , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura
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