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In this study, a non-intrusive method to directly measure the fluid temperature and two-phase flow patterns in micro-scale system was developed. To achieve this goal, an adequate calibration process of infrared (IR) thermography measurement and an experimental design of IR transparent convective flow in a microchannel were established. The temperature distribution of the fluid along the microchannel was measured by IR thermography through a germanium window of thickness 5 mm. The transparent germanium window was used to facilitate the transmission of long-wavelength IR rays. The infrared images were obtained at a frame rate of 200 fps, which enabled observation of the transient temperature behavior during flow boiling in the microchannel. A semi-transparent liquid, namely ethanol, was used as the working fluid, with a mass flux of 20.3 kg/m 2 s and heat flux range of 3.1–244.1 kW/m 2 . The experimental results confirmed that IR thermography could be used to capture the transient single- and two-phase flow patterns as well as the fluid temperature along the channel. To the best of our knowledge, this paper is the first presentation of IR visualization of two-phase flow patterns in a microchannel. The trends of the local heat transfer coefficients with respect to the two-phase flow patterns are discussed, and the experimentally determined coefficients are compared with those calculated by commonly used equations.

This study investigates the evolution of an Escherichia coli sequence type 219 clone in a patient with recurrent urinary tract infection, comparing isolate EC974 obtained prior to antibiotic treatment and isolate EC1515 recovered after exposure to several β-lactam antibiotics (ceftriaxone, cefixime, and imipenem). EC974 had a smooth colony morphology, while EC1515 had a rough colony morphology on sheep blood agar. RAPD-PCR analysis suggested that both isolates belonged to the same clone. Antimicrobial susceptibility tests showed that EC1515 was more resistant to piperacillin/tazobactam, cefepime, cefpirome, and ertapenem than EC974. Comparative genomic analysis was used to investigate the genetic changes of EC974 and EC1515 within the host, and showed three plasmids with replicons IncI1, P0111, and IncFII in both isolates. P0111-type plasmids pEC974-2 and pEC1515-2, contained the antibiotic resistance genes aadA2, tetA, and drfA12. IncFII-type plasmids pEC974-3 and pEC1515-3 contained the antibiotic resistance genes blaTEM−1, aadA1, aadA22, sul3, and inuF. Interestingly, blaCMY−111 and blaCMY−4 were found in very similar IncI1 plasmids that also contained aadA22 and aac(3)-IId, from isolates EC974 (pEC974-1) and EC1515 (pEC1515-1), respectively. The results showed in vivo amino acid substitutions converting blaCMY−111 to blaCMY−4 (R221W and A238V substitutions). Conjugation experiments showed a high frequency of IncI1 and IncFII plasmid co-transference. Transconjugants and DH5α cells harboring blaCMY-4 or blaCMY-111 showed higher levels of resistance to ampicillin, amoxicillin, cefazolin, cefuroxime, cefotaxime, cefixime, and ceftazidime, but not piperacillin/tazobactam, cefpime, or ertapenem. All known genes (outer membrane proteins and extended-spectrum AmpC β-lactamases) involved in ETP resistance in E. coli were identical between EC974 and EC1515. This is the first study to identify the evolution of an IncI1 plasmid within the host, and to characterize blaCMY−111 in E. coli.

This study investigates the evolution of an Escherichia coli sequence type 219 clone in a patient with recurrent urinary tract infection, comparing isolate EC974 obtained prior to antibiotic treatment and isolate EC1515 recovered after exposure to several β-lactam antibiotics (ceftriaxone, cefixime, and imipenem). EC974 had a smooth colony morphology, while EC1515 had a rough colony morphology on sheep blood agar. RAPD-PCR analysis suggested that both isolates belonged to the same clone. Antimicrobial susceptibility tests showed that EC1515 was more resistant to piperacillin/tazobactam, cefepime, cefpirome, and ertapenem than EC974. Comparative genomic analysis was used to investigate the genetic changes of EC974 and EC1515 within the host, and showed three plasmids with replicons IncI1, P0111, and IncFII in both isolates. P0111-type plasmids pEC974-2 and pEC1515-2, contained the antibiotic resistance genes aadA2, tetA, and drfA12. IncFII-type plasmids pEC974-3 and pEC1515-3 contained the antibiotic resistance genes blaTEM−1, aadA1, aadA22, sul3, and inuF. Interestingly, blaCMY−111 and blaCMY−4 were found in very similar IncI1 plasmids that also contained aadA22 and aac(3)-IId, from isolates EC974 (pEC974-1) and EC1515 (pEC1515-1), respectively. The results showed in vivo amino acid substitutions converting blaCMY−111 to blaCMY−4 (R221W and A238V substitutions). Conjugation experiments showed a high frequency of IncI1 and IncFII plasmid co-transference. Transconjugants and DH5α cells harboring blaCMY-4 or blaCMY-111 showed higher levels of resistance to ampicillin, amoxicillin, cefazolin, cefuroxime, cefotaxime, cefixime, and ceftazidime, but not piperacillin/tazobactam, cefpime, or ertapenem. All known genes (outer membrane proteins and extended-spectrum AmpC β-lactamases) involved in ETP resistance in E. coli were identical between EC974 and EC1515. This is the first study to identify the evolution of an IncI1 plasmid within the host, and to characterize blaCMY−111 in E. coli.

According to cytogenetic aberrations, sarcomas can be categorized as complex or simple karyotype tumors. Alternative lengthening of telomeres is a telomere-maintenance mechanism common in sarcomas. Recently, this mechanism was found to be associated with loss of either α-thalassemia/mental retardation syndrome X-linked (ATRX) or death domain-associated (DAXX) protein. We previously reported that alternative lengthening of telomeres and loss of ATRX expression were common in leiomyosarcoma, angiosarcoma, pleomorphic liposarcoma, and dedifferentiated liposarcoma. In the present study, we screened an additional 245 sarcomas of other types to determine the prevalence of alternative lengthening of telomeres, loss of ATRX/DAXX expression, and their relationship. Undifferentiated pleomorphic sarcomas were frequently alternative lengthening of telomeres positive (65%) and loss of ATRX was seen in approximately half of the alternative lengthening of telomeres-positive tumors. Nineteen of 25 myxofibrosarcomas were alternative lengthening of telomeres-positive, but only one was ATRX deficient. Three of 15 radiation-associated sarcomas were alternative lengthening of telomeres positive, but none of them was ATRX deficient. Alternative lengthening of telomeres and/or loss of ATRX were uncommon in malignant peripheral nerve sheath tumors, gastrointestinal stromal tumors, and embryonal rhabdomyosarcomas. By contrast, none of the 71 gene fusion-associated sarcomas was ATRX deficient or alternative lengthening of telomeres positive. All tumors exhibited preserved DAXX expression. Combining our previous studies and this study, a total of 384 sarcomas with complex karyotypes were examined, 83 of which were ATRX deficient (22%). By telomere-specific fluorescence in situ hybridization, 45% (138/308) were alternative lengthening of telomeres positive, 55% (76/138) of which were ATRX deficient. Loss of ATRX was highly associated with alternative lengthening of telomeres (P

The distribution of Lrp target genes in different functional categories. (DOCX 334Â kb)

Location of point mutation in lrp of V. vulnificus mutant NY303. (DOCX 72Â kb)

The mRNA levels of genes predicted to be involved in iron-acquisition and chemotaxis in the wild-type strain and Î lrp mutant. (DOCX 219Â kb)

Phagocytosis of various V. vulnificus strains by RAW 264.7 cells after mixed infection. (DOCX 55Â kb)

The mRNA levels of lrp in the wild-type strain incubated in various media. (DOCX 158Â kb)

In this paper, we present an experimental study on a two-phase boiling heat transfer of liquid methanol in co- and counter-current microchannel heat exchangers (MCHEs) with gas heating. The silicon-based MCHE with dimensions of 20 × 20 × 2 mm is designed with 18 microchannels. The working fluids on the hot and cold sides of the MCHE are helium and liquid methanol, respectively. During the study, the helium fluid inlet temperature is varied from 40 to 250 °C, while the mass flux is fixed at 10 kg/m 2 s; additionally, the mass flux of the liquid methanol is varied from 3 to 9 kg/m 2 s, and the inlet temperature is varied from room temperature to the saturation temperature of methanol, depending on the hot-side heat flux. The results demonstrate that the convective boiling heat transfer increases with the mean vapor quality until approaching the critical heat flux (CHF) condition. The counter-current MCHE exhibits a higher CHF due to a higher inlet subcooling temperature than the co-current MCHE. The single-phase and convective boiling heat transfer coefficients are measured and compared with the existing correlations. Moreover, two empirical correlations for the two-phase boiling heat transfer coefficient for the MCHEs are proposed in this study.

To learn how to utilize the exhaust heat from a high-temperature gas product of a methanol reformer, the present study experimentally investigates the boiling two-phase flow in co- and counter-current microchannel heat exchangers (MCHE) with gas heating. Boiling two-phase flow patterns, two-phase flow instability, and efficiency are explored. The working fluid on the hot and cold sides are helium and liquid methanol, respectively. The silicon-based MCHE, which has dimensions of 20 mm × 20 mm, is designed with 18 parallel microchannels on both sides and is prepared using microfabrication processes. Four types of two-phase flow patterns – bubbly-elongated slug flow, annular flow, annular flow with liquid film breakup, and dryout are identified in both types of MCHE that are studied. A flow pattern map is then constructed on the plane of the methanol mass flux versus heat flux for both types of MCHE. In the counter-current MCHE, the efficiency increases significantly with an increase in the mass flux in both the single- and two-phase flow regions, while the effect of mass flux is insignificant in the co-current MCHE. In the two-phase flow region, the efficiency of both types of MCHEs gradually increases with an increase in the hot-side thermal power until the CHF is approached. The highest efficiency obtained in the present study is about 0.85 and 0.90 for the co- and counter-current MCHEs, respectively.

Transport of water through the gas diffusion layer (GDL) is explored to simulate the water flow in the cathode of a proton exchange membrane fuel cell (PEMFC). In this study, several commercial GDL media, including carbon paper and carbon cloth with or without a microporous layer (MPL), are employed. Liquid water is injected through the GDL media, and the differential pressure drop is measured to analyze the dynamic features of the water flow through the different structures of the GDL samples. Moreover, by combining the top-view images of the water droplet that emerges out of the GDL with the results of the dynamic measurement of the differential pressure drop, the water saturation inside the GDL after the water breakthrough through the GDL is analyzed. The “self-eruption transport” mechanism, which may control the water contained inside the GDL regardless of the water generation rate, is observed in the GDL whose one side is treated with MPL only. This suggests that a GDL with single-side MPL treatment may help effectively water management.

The present study investigates the effect of flow arrangement on heat transfer characteristics in two-phase microchannel heat exchangers (MCHEs) with gas heating. The microchannel heat exchangers are developed to utilize the exhaust heat from a high-temperature gas product of a methanol reformer (a part of a reformed methanol fuel cell). Co-and counter-current flow types of MCHE are tested. Working fluids in the hot and cold sides are helium and liquid methanol, respectively. For both single-phase flow regions, the experimental results indicate that the actual effectiveness of the counter-current MCHE is higher than that of the co-current MCHE. Both of the actual effectiveness of co-and counter-current MCHEs significantly increases with an increase of cold side mass flux. Moreover, the actual effectiveness for both types of MCHE is less relationship to the hot-side thermal power in single-phase zone. The highest actual effectiveness is about 0.6 and 0.72 for co-and counter-current MCHEs, respectively.