bluuebunny/crossref_metadata_2025_split huggingface dataset:
Charge‐exchange X‐ray emission at hot/cool gas interfaces
Authors: Lallement R. 
Published: April 2012

AbstractCharge‐transfer (CT) X‐ray emission may occur at interfaces between a partially neutral gas and gas possessing high ions, provided there is a relative motion between those two phases. The CTX surface brightness from distant objects must be taken into account if it is not far below other “classical” emission sources, especially the thermal emission from the hot phase. I discuss those conditions and potential spectroscopic or photometric diagnostics. I also mention potential indirect effects of the CT reactions by means of pickup ion production, acceleration and subsequent modification of interface and plasma properties (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transfer reactions at interfaces between neutral gas and plasma: Dynamical effects and X‐ray emission
Authors: Provornikova E. , Izmodenov V.V. , Lallement R. 
Published: April 2012

AbstractCharge‐transfer is the main process linking neutrals and charged particles in the interaction regions of neutral (or partly ionized) gas with a plasma. In this paper we illustrate the importance of charge‐transfer with respect to the dynamics and the structure of neutral gas‐plasma interfaces. We consider the following phenomena: (1) the heliospheric interface ‐ region where the solar wind plasma interacts with the partly‐ionized local interstellar medium (LISM) and (2) neutral interstellar clouds embedded in a hot, tenuous plasma such as the million degree gas that fills the so‐called “Local Bubble”. In (1), we discuss several effects in the outer heliosphere caused by charge exchange of interstellar neutral atoms and plasma protons. In (2) we describe the role of charge exchange in the formation of a transition region between the cloud and the surrounding plasma based on a two‐component model of the cloud‐plasma interaction. In the model the cloud consists of relatively cold and dense atomic hydrogen gas, surrounded by hot, low density, fully ionized plasma. We discuss the structure of the cloud‐plasma interface and the effect of charge exchange on the lifetime of interstellar clouds. Charge transfer between neutral atoms and minor ions in the plasma produces X‐ray emission. Assuming standard abundances of minor ions in the hot gas surrounding the cold interstellar cloud, we estimate the X‐ray emissivity consecutive to the charge transfer reactions. Our model shows that the charge‐transfer X‐ray emission from the neutral cloud‐plasma interface may be comparable to the diffuse thermal X‐ray emission from the million degree gas cavity itself (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chondroitin sulfate and dynamic loading alter chondrogenesis of human MSCs in PEG hydrogels
Authors: Steinmetz Neven J. , Bryant Stephanie J. 
Published: April 2012

AbstractWhile biochemical and biomechanical cues are known to play important roles in directing stem cell differentiation, there remains little known regarding how these inextricably linked biological cues impact the differentiation fate of human marrow stromal cells (hMSCs). This study investigates the chondrogenic differentiation potential of hMSCs when encapsulated in a three dimensional (3D) hydrogel and exposed to a biochemical cue, chondroitin sulfate (ChS), a biomechanical cue, dynamic loading, and their combination. hMSCs were encapsulated in bioinert poly(ethylene glycol) (PEG) hydrogels only, PEG hydrogels modified with covalently incorporated methacrylated ChS and cultured under free swelling conditions or subjected to delayed intermittent dynamic loading for 2 weeks. The 3D hydrogel environment led to the expression of chondrogenic genes (SOX9) and proteins (aggrecan and collagen II), but also upregulated hypertrophic genes (RUNX2 and Col X mRNA) and proteins (collagen X), while the application of loading generally led to a downregulation in chondrogenic proteins (collagen II). The presence of ChS led to elevated levels of aggrecan, but also collagen I, protein expression and when combined with dynamic loading downregulated, but did not suppress, hypertrophic genes (Col X and RUNX2) and collagen I protein expression. Taken together, this study demonstrates that while the 3D environment induces early terminal differentiation during chondrogenesis of hMSCs, the incorporation of ChS into PEG hydrogels may slow the terminal differentiation process down the hypertrophic lineage particularly when dynamic loading is applied. Biotechnol. Bioeng. 2012; 109: 2671–2682. © 2012 Wiley Periodicals, Inc.
Predictive models for transient protein expression in tobacco (Nicotiana tabacum L.) can optimize process time, yield, and downstream costs
Authors: Buyel J.F. , Fischer R. 
Published: April 2012

AbstractThe transient expression of recombinant biopharmaceutical proteins in plants can suffer inter‐batch variation, which is considered a major drawback under the strict regulatory demands imposed by current good manufacturing practice (cGMP). However, we have achieved transient expression of the monoclonal antibody 2G12 and the fluorescent marker protein DsRed in tobacco leaves with ∼15% intra‐batch coefficients of variation, which is within the range reported for transgenic plants. We developed models for the transient expression of both proteins that predicted quantitative expression levels based on five parameters: The OD600nm of Agrobacterium tumefaciens (from 0.13 to 2.00), post‐inoculation incubation temperature (15–30°C), plant age (harvest at 40 or 47 days after seeding), leaf age, and position within the leaf. The expression models were combined with a model of plant biomass distribution and extraction, generating a yield model for each target protein that could predict the amount of protein in specific leaf parts, individual leaves, groups of leaves, and whole plants. When the yield model was combined with a cost function for the production process, we were able to perform calculations to optimize process time, yield, or downstream costs. We illustrate this procedure by transferring the cost function from a production process using transgenic plants to a hypothetical process for the transient expression of 2G12. Our models allow the economic evaluation of new plant‐based production processes and provide greater insight into the parameters that affect transient protein expression in plants. Biotechnol. Bioeng. 2012; 109: 2575–2588. © 2012 Wiley Periodicals, Inc.
Improvement of surfactin production in Bacillus subtilis using synthetic wastewater by overexpression of specific extracellular signaling peptides, comX and phrC
Authors: Jung Ju , Yu Kyung Ok , Ramzi Ahmad Bazli , Choe Se Hoon , Kim Seung Wook , Han Sung Ok 
Published: April 2012

AbstractSurfactin is a biological surfactant with numerous potential applications. In this study, Bacillus subtilis was engineered to improve surfactin production by the activation of two competence‐stimulating pheromones, ComX and competence and sporulation factor (CSF) to stimulate the transcription of srfA operon. Both signaling factors, encoded by comX and phrC, were successfully overexpressed and subsequently increased surfactin production. Surfactin produced by engineered strains showed functional groups similar to the commercially available surfactin analyzed via Fourier transform infrared spectroscopy (FTIR). Surfactin production in the B. subtilis (pHT43‐comXphrC) strain was 6.4‐fold greater than in the wild strain, with approximately 135.1 mg/L surfactin produced after 48 h cultivation. To reduce the production costs of surfactin, synthetic wastewater was used, from which the B. subtilis (pHT43‐comXphrC) strain produced approximately 140.2 mg/L surfactin. The results obtained demonstrated the production of surfactin from synthetic wastewater, which is beneficial in lowering the overall production costs. Biotechnol. Bioeng. 2012;109: 2349–2356. © 2012 Wiley Periodicals, Inc.
Photosynthetic efficiency of Chlamydomonas reinhardtii in attenuated, flashing light
Authors: Vejrazka Carsten , Janssen Marcel , Streefland Mathieu , Wijffels René H. 
Published: April 2012

AbstractAs a result of mixing and light attenuation, algae in a photobioreactor (PBR) alternate between light and dark zones and, therefore, experience variations in photon flux density (PFD). These variations in PFD are called light/dark (L/D) cycles. The objective of this study was to determine how these L/D cycles affect biomass yield on light energy in microalgae cultivation. For our work, we used controlled, short light path, laboratory, turbidostat‐operated PBRs equipped with a LED light source for square‐wave L/D cycles with frequencies from 1 to 100 Hz. Biomass density was adjusted that the PFD leaving the PBR was equal to the compensation point of photosynthesis. Algae were acclimated to a sub‐saturating incident PFD of 220 µmol m−2 s−1 for continuous light. Using a duty cycle of 0.5, we observed that L/D cycles of 1 and 10 Hz resulted on average in a 10% lower biomass yield, but L/D cycles of 100 Hz resulted on average in a 35% higher biomass yield than the yield obtained in continuous light. Our results show that interaction of L/D cycle frequency, culture density and incident PFD play a role in overall PBR productivity. Hence, appropriate L/D cycle setting by mixing strategy appears as a possible way to reduce the effect that dark zone exposure impinges on biomass yield in microalgae cultivation. The results may find application in optimization of outdoor PBR design to maximize biomass yields. Biotechnol. Bioeng. 2012; 109: 2567–2574. © 2012 Wiley Periodicals, Inc.
Rapid micropatterning of cell lines and human pluripotent stem cells on elastomeric membranes
Authors: Paik Isha , Scurr David J. , Morris Bryan , Hall Graham , Denning Chris , Alexander Morgan R. , Shakesheff Kevin M. , Dixon James E. 
Published: April 2012

AbstractTissue function during development and in regenerative medicine completely relies on correct cell organization and patterning at micro and macro scales. We describe a rapid method for patterning mammalian cells including human embryonic stem cells (HESCs) and induced pluripotent stem cells (iPSCs) on elastomeric membranes such that micron‐scale control of cell position can be achieved over centimeter‐length scales. Our method employs surface engineering of hydrophobic polydimethylsiloxane (PDMS) membranes by plasma polymerization of allylamine. Deposition of plasma polymerized allylamine (ppAAm) using our methods may be spatially restricted using a micro‐stencil leaving faithful hydrophilic ppAAm patterns. We employed airbrushing to create aerosols which deposit extracellular matrix (ECM) proteins (such as fibronectin and Matrigel™) onto the same patterned ppAAm rich regions. Cell patterns were created with a variety of well characterized cell lines (e.g., NIH‐3T3, C2C12, HL1, BJ6, HESC line HUES7, and HiPSC line IPS2). Individual and multiple cell line patterning were also achieved. Patterning remains faithful for several days and cells are viable and proliferate. To demonstrate the utility of our technique we have patterned cells in a variety of configurations. The ability to rapidly pattern cells at high resolution over macro scales should aid future tissue engineering efforts for regenerative medicine applications and in creating in vitro stem cell niches. Biotechnol. Bioeng. 2012; 109: 2630–2641. © 2012 Wiley Periodicals, Inc.
Hepatic venous pressure gradient in the assessment of portal hypertension before liver resection in patients with cirrhosis
Authors: Boleslawski E , Petrovai G , Truant S , Dharancy S , Duhamel A , Salleron J , Deltenre P , Lebuffe G , Mathurin P , Pruvot F R 
Published: April 2012

Abstract

Background
Preoperative measurement of hepatic venous pressure gradient (HVPG) is not performed routinely before hepatectomy in patients with cirrhosis, although it has been suggested to be useful. This study investigated whether preoperative HVPG values and indirect criteria of portal hypertension (PHT) predict the postoperative course in these patients.

Methods
Between January 2007 and December 2009, consecutive patients with resectable hepatocellular carcinoma (HCC) in a cirrhotic liver were included in this prospective study. PHT was assessed by transjugular HVPG measurement and by classical indirect criteria (oesophageal varices, splenomegaly and thrombocytopenia). The main endpoints were postoperative liver dysfunction and 90-day mortality.

Results
Forty patients were enrolled. A raised HVPG was associated with postoperative liver dysfunction (median 11 and 7 mmHg in those with and without dysfunction respectively; P = 0·017) and 90-day mortality (12 and 8 mmHg in those who died and survivors respectively; P = 0·026). Oesophageal varices, splenomegaly and thrombocytopenia were not associated with any of the endpoints. In multivariable analysis, body mass index, remnant liver volume ratio and preoperative HVPG were the only independent predictors of postoperative liver dysfunction.

Conclusion
An increased HVPG was associated with postoperative liver dysfunction and mortality after liver resection in patients with HCC and liver cirrhosis, whereas indirect criteria of PHT were not. This study suggests that preoperative HVPG measurement should be measured routinely in these patients.
Selective separation of biobutanol from acetone–butanol–ethanol fermentation broth by means of sorption methodology based on a novel macroporous resin
Authors: Lin Xiaoqing , Wu Jinglan , Jin Xiaohong , Fan Jiansheng , Li Renjie , Wen Qingshi , Qian Wenbin , Liu Dong , Chen Xiaochun , Chen Yong , Xie Jingjing , Bai Jianxin , Ying Hanjie 
Published: April 2012

AbstractThe traditional distillation method for recovery of butanol from fermentation broth is an energy‐intensive process. Separation of butanol based on adsorption methodology has advantages in terms of biocompatibility and stability, as well as economy, and therefore gains much attention. However, the application of the commercial adsorbents in the integrated acetone–butanol–ethanol (ABE) fermentation process is restricted due to the low recovery (less than 85%) and the weak capability of enrichment in the eluent (3–4 times). In this study, we investigated the sorption properties of butanol onto three kinds of adsorbents with different polarities developed in our laboratory, that is, XD‐41, H‐511, and KA‐I resin. The sorption behaviors of single component and ABE ternary mixtures presented in the fermentation broths on KA‐I resin were investigated. KA‐I resin had higher affinity for butanol than for acetone, ethanol, glucose, acetic acid, and butyric acid. Multicomponent ABE sorption on KA‐I resin was modeled using a single site extended Langmuir isotherm model. In a desorption study, all the adsorbed components were desorbed in one bed volume of methanol, and the recovery of butanol from KA‐I resin was 99.7%. The concentration of butanol in the eluent was increased by a factor of 6.13. In addition, KA‐I resin was successfully regenerated by two bed volumes of water. Because of its quick sorption, high sorption capacity, low cost, and ease of desorption and regeneration, KA‐I resin exhibits good potential for compatibility with future ABE fermentation coupled with in situ recovery product removal techniques. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 28: 962–972, 2012
Diminished left ventricular function is associated with poor mid‐term outcomes in neonates after balloon aortic valvuloplasty
Authors: Petit Christopher J. , Ing Frank F. , Mattamal Raphael , Pignatelli Ricardo H. , Mullins Charles E. , Justino Henri 
Published: April 2012

AbstractObjectivesWe studied outcomes of neonatal aortic valvuloplasty to determine the risk factors for poor outcomes.BackgroundBalloon aortic valvuloplasty (BAV) is the primary therapy for neonates with severe aortic stenosis (AS). Limited data are available on the mid‐term and long‐term outcomes in this population, and reported risk factors for poor outcomes vary among studies.MethodsWe reviewed all cases of BAV in neonates in our institution between 1998 and 2009. We reviewed patient characteristics, preintervention echocardiographic, and procedural details. We tracked repeat BAV, aortic valve replacement (AVR), and death/transplant. Kaplan–Meier and Cox regression analyses were performed. Changes in dimensions of left heart structures post‐BAV were also studied.ResultsForty‐eight neonates were included—of these, 30 (62%) had critical AS. There was one procedural death. The remaining 47 neonates were followed for 4.8 ± 4.4 years. Repeat BAV was performed in 19 (40%) neonates; AVR was performed in 9 (19%), and death/transplant occurred in 4 (8%) neonates. Multivariate analysis revealed that lower LV shortening fraction pre‐BAV, higher pre‐BAV and final valve gradient, and need for inotropes were associated with poor long‐term outcomes. LV diastolic and systolic dimensions normalized over time, and left heart structures improved in size early and late after BAV.ConclusionsNeonatal BAV is associated with low mortality. Lower LV shortening fraction pre‐BAV is associated with risk of future interventions, while repeat valvuloplasty is safe and effective for recurrent AS. There is significant improvement in dimensions of the LV and aortic valve annulus following BAV. © 2012 Wiley Periodicals, Inc.
Over‐the‐wire‐technique device implantation
Authors: Butera Gianfranco , Castaldi Biagio , MacDonald Simon T. 
Published: April 2012

AbstractIntroductionTranscatheter closure of cardiac defects is a mainstay of treatment in congenital and structural heart disease. Occasionally, the devices used are useful in nonstandard or difficult positions but device embolization and malposition can be complicating factors necessitating percutaneous retrieval or emergency surgery. We describe a new “over‐the‐wire” technique that allows guided safe deployment and easy retrievability if required.MethodsWe describe 5 cases in which Amplatzer devices were delivered over a wire in challenging anatomy in high‐risk patients. These cases included baffle leak in complex congenital heart disease, paravalvular leak, a large patent ductus arteriosus, and complex ventricular septal defects. In each case, the device was punctured close to the release mechanism and a guidewire fed through it, the device and guidewire then being loaded into the appropriate delivery system. The procedure is described in each case, illustrating the use of the technique.ConclusionWe describe a novel over‐the‐wire technique that is useful in deployment of Amplatzer devices in difficult and challenging anatomy, allowing careful controlled delivery and easy retrieval. This will help minimize procedural patient risk in complex cases. © 2012 Wiley Periodicals, Inc.
Novel use of the Mguard™ mesh‐covered stent to treat coronary arterial perforations
Authors: Romaguera Rafael , Gomez‐Hospital Joan Antoni , Cequier Angel 
Published: April 2012

AbstractCovered stents seem to be an effective tool to seal severe perforations that have persisted despite prolonged balloon inflation. However, the high profile and low flexibility of previous covered stents compromise the deliverability of these devices, particularly in emergency situations. The Mguard™ stent (InspireMD, Tel Aviv, Israel) is a novel mesh‐covered stent that has been designed to prevent distal embolization in thrombotic lesions. We herein report two cases that describe a new potential use of the Mguard stent for sealing perforations in coronary circulation. © 2012 Wiley Periodicals, Inc.
Embolic protection device utilization during stenting of native coronary artery lesions with large lipid core plaques as detected by near‐infrared spectroscopy
Authors: Brilakis Emmanouil S. , Abdel‐Karim Abdul‐Rahman R. , Papayannis Aristotelis C. , Michael Tesfaldet T. , Rangan Bavana V. , Johnson Jason L. , Banerjee Subhash 
Published: April 2012

AbstractBackgroundStenting of large lipid core plaques (LCPs), as assessed by near‐infrared spectroscopy (NIRS), has been associated with periprocedural myocardial infarction (MI), possibly due to distal embolization.MethodsAn embolic protection device (EPD) was inserted before stenting in nine native coronary arteries with large LCP, as assessed by NIRS. Embolized material was assessed by histopathology.ResultsMean age was 64 ± 7 years and all patients were men. The target lesion was located in the right (67%) or left anterior descending (33%) coronary artery. A filter was utilized in eight patients (89%) and proximal embolic protection in one (11%). In one patient two filters were required because the originally placed filter became obstructed with debris after initial stent placement. The mean percent angiographic stenosis prestenting and poststenting was 87% ± 9% and 2% ± 4%, respectively and final TIMI 3 flow was achieved in all patients. Embolized material was retrieved in eight of nine patients (89%) and consisted mainly of platelet and fibrin thrombi. The mean target segment lipid core burden index decreased from 395 ± 114 before stenting to 152 ± 106 after stenting (P < 0.001) and the lesion angular extent decreased from 312° ± 70° to 240° ± 90° (P = 0.07). Postprocedural MI occurred in two of nine patients (22%), in one of whom two filters were required.ConclusionUse of EPDs frequently resulted in embolized material retrieval after stenting of native coronary artery lesions with large LCPs. These findings support further study of EPDs as a means to prevent poststenting MI. © 2012 Wiley Periodicals, Inc.
Severe hemolysis associated with use of the impella LP 2.5 mechanical assist device
Authors: Sibbald Matthew , Džavík Vladimír 
Published: April 2012

AbstractThe Impella LP 2.5 is a percutaneously implantable axial flow device designed to offer circulatory support for patients in cardiogenic shock during percutaneous coronary interventions (PCI). While most axial flow devices are associated with hemolysis, clinically relevant hemolysis with this device has not been reported. We report a case of a 66‐year‐old woman with hemodynamic collapse during an elective PCI who was successfully resuscitated with an Impella device. She developed marked biochemical evidence of intravascular hemolysis. This necessitated device removal which resulted in prompt resolution of the hemolysis. We advise routine measurement of biochemical markers of hemolysis and serial hemoglobin values during Impella device support to allow timely detection and treatment of this important complication. © 2012 Wiley Periodicals, Inc.