bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlling Hierarchy in Solution‐processed Polymer Solar Cells Based on Crosslinked P3HT
Authors: Tao Chen , Aljada Muhsen , Shaw Paul E. , Lee Kwan H. , Cavaye Hamish , Balfour Michael N. , Borthwick Robert J. , James Michael , Burn Paul L. , Gentle Ian R. , Meredith Paul
Published: August 2012

Understanding and controlling the morphology of donor/acceptor blends is critical for the development of solution processable organic solar cells. By crosslinking a poly(3‐n‐hexylthiophene‐2,5‐diyl) (P3HT) film we have been able to spin‐coat [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) onto the film to form a structure that is close to a bilayer, thus creating an ideal platform for investigating interdiffusion in this model system. Neutron reflectometry (NR) demonstrates that without any thermal treatment a smaller amount of PCBM percolates throughout the crosslinked P3HT when compared to a non‐crosslinked P3HT film. Using time‐resolved NR we also show thermal annealing increases the rate of diffusion, resulting in a near‐uniform distribution of PCBM throughout the polymer film. XPS measurements confirm the presence of both P3HT and PCBM at the annealed film's surface indicating that the two components are intermixed. Photovoltaic devices fabricated using this bilayer approach and suitable annealing conditions yielded comparable power conversion efficiencies to bulk heterojunction devices made from the same materials. The crosslinking procedure has also enabled the formation of patterned P3HT films by photolithography. Pillars with feature sizes down to 2 μm were produced and after subsequent deposition of PCBM and thermal annealing devices with efficiencies of up to 1.4% were produced.
Effect of injection zone cracking on fluid catalytic cracking
Authors: Patel Rajesh , Wang Dawei , Zhu Chao , Ho Teh C.
Published: August 2012

Fluid catalytic cracking (FCC) is a refining process for converting heavy oils to valuable products such as gasoline and olefins. Modeling of this process is quite challenging. A common assumption has been that vaporization is instantaneously fast and cracking is negligible in the injection zone. Relaxing this assumption, an approach for quantifying the effect of injection zone cracking on FCC performance is developed. The approach combines a Lagrangian description of the spray behavior with an Eulerian modeling of transport‐cracking coupling in the FCC riser. Included in the model are droplet vaporization, a four‐lump kinetic network, spray penetration trajectory, solid‐fluid and solid‐solid collisions, and multispray interactions. Parametric studies show that precracking in the injection zone plays an important role in steering the overall performance of an FCC riser. The model developed here can accommodate a large number of reactions, thus, allowing for composition‐based modeling of the FCC process. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1226–1235, 2013
Arthrogryposis (multiple congenital contractures) associated with failed termination of pregnancy
Authors: Hall Judith G.
Published: August 2012

The purpose of this study was to establish whether an increase in failed termination of pregnancy is observed among individuals with arthrogryposis (multiple congenital contractures). A total of 2,500 unselected patients with arthrogryposis collected by the author over a 35‐year period were reviewed. The cases included referrals, consultations, personal examinations, and correspondence. They were reviewed for clinical features, pregnancy complications, family history, and a history of attempted terminations of the pregnancy. Eleven cases of failed terminations of pregnancy in which the individuals were subsequently born with arthrogryposis were identified. We conclude that infants who survive attempted termination of pregnancy (both surgical and medical) may be at an increased risk to be born with multiple congenital contractures. Careful examination of the tissue and a post‐procedure ultrasound will help to assure that the termination has been successful. Those infants surviving attempted termination of pregnancy who have arthrogryposis are also at >50% risk for intellectual disability. © 2012 Wiley Periodicals, Inc.
SMARCAL1 deficiency predisposes to non‐Hodgkin lymphoma and hypersensitivity to genotoxic agents in vivo
Authors: Baradaran‐Heravi Alireza , Raams Anja , Lubieniecka Joanna , Cho Kyoung Sang , DeHaai Kristi A. , Basiratnia Mitra , Mari Pierre‐Olivier , Xue Yutong , Rauth Michael , Olney Ann Haskins , Shago Mary , Choi Kunho , Weksberg Rosanna A. , Nowaczyk Malgorzata J.M. , Wang Weidong , Jaspers Nicolaas G.J. , Boerkoel Cornelius F.
Published: August 2012

Schimke immuno‐osseous dysplasia (SIOD) is a multisystemic disorder with prominent skeletal, renal, immunological, and ectodermal abnormalities. It is caused by mutations of SMARCAL1 (SWI/SNF‐related, matrix‐associated, actin‐dependent regulator of chromatin, subfamily a‐like 1), which encodes a DNA stress response protein. To determine the relationship of this function to the SIOD phenotype, we profiled the cancer prevalence in SIOD and assessed if defects of nucleotide excision repair (NER) and nonhomologous end joining (NHEJ), respectively, explained the ectodermal and immunological features of SIOD. Finally, we determined if Smarcal1del/del mice had hypersensitivity to irinotecan (CPT‐11), etoposide, and hydroxyurea (HU) and whether exposure to these agents induced features of SIOD. Among 71 SIOD patients, three had non‐Hodgkin lymphoma (NHL) and one had osteosarcoma. We did not find evidence of defective NER or NHEJ; however, Smarcal1‐deficient mice were hypersensitive to several genotoxic agents. Also, CPT‐11, etoposide, and HU caused decreased growth and loss of growth plate chondrocytes. These data, which identify an increased prevalence of NHL in SIOD and confirm hypersensitivity to DNA damaging agents in vivo, provide guidance for the management of SIOD patients. © 2012 Wiley Periodicals, Inc.
Atypical amyoplasia congenita in an infant with Leigh syndrome: A mitochondrial cause of severe contractures?
Authors: Wilnai Yael , Seaver Laurie H. , Enns Gregory M.
Published: August 2012

Amyoplasia congenita is a distinct form of arthrogryposis with characteristic features including internally rotated and adducted shoulders, extended elbows, flexion, and ulnar deviation of the wrists, and adducted thumbs. Fetal hypokinesia, secondary to a variety of genetic conditions, neuromuscular disorders, and environmental agents, is associated with contractures. In order to increase our understanding of the phenotypic spectrum associated with SURF 1 deficiency, a common cause of mitochondrial respiratory chain complex IV deficiency and Leigh syndrome, we describe a now 6‐year‐old boy who presented in the neonatal period with amyoplasia congenita. His development was normal until age 10.5 months, at which time he developed severe hypotonia and choreoathetosis following an episode of viral gastroenteritis. Following the onset of neurological symptoms, he gradually developed severe kyphosis and lower limb contractures. Blood and cerebrospinal fluid lactate levels were elevated and head imaging showed characteristic features of Leigh syndrome. He was found to harbor two pathogenic heterozygous mutations in the SURF 1 gene. In this case, mitochondrial dysfunction and the resultant energy deficiency may have played a role in causing abnormal neuronal development during embryogenesis, causing arthrogryposis. A variety of mitochondrial respiratory chain complex deficiencies have been associated with contractures of varying severity. Therefore, mitochondrial disorders should be considered in the differential diagnosis of neonatal arthrogryposis, especially if other characteristic findings such as lactic acidemia or basal ganglia abnormalities are present. © 2012 Wiley Periodicals, Inc.
Normative growth charts for individuals with Costello syndrome
Authors: Sammon Mary R. , Doyle Dan , Hopkins Elizabeth , Sol‐Church Katia , Stabley Deborah L. , McGready John , Schulze Kerry , Alade Yewande , Hoover‐Fong Julie , Gripp Karen W.
Published: August 2012

Costello syndrome is a rare condition due to heterozygous germline mutations in the proto‐oncogene HRAS. It affects multiple organ systems and includes severe failure‐to‐thrive, short stature, and macrocephaly. The goal of this study was to develop Costello syndrome‐specific growth curves. We collected height, weight, and head circumference (OFC) measurements from 94 individuals (45 males and 49 females). Their HRAS mutation spectrum reflects previously published cohorts, with p.G12S in 77.7%. Participants received medical care, therefore our data does not reflect natural history per se, but rather growth with nutritional support. Due to limited cohort size, we analyzed data from males and females together. Weight‐for‐age data included 417 separate measurements from 80 individuals age 0–36 months, and 585 measurements from 82 individuals for age 0–10 years. Height‐for‐age data were derived from 391 measurements from 77 individuals age 0–36 months, and 591 measurements from 90 individuals age 0–10 years. Measurements obtained after growth hormone exposure in 15 individuals were excluded in this analysis. The OFC curve was derived from 221 measurements from 55 individuals age 0–36 months. Centiles (5th, 50th, and 95th) were estimated across the age continuum for each growth parameter, and compared to gender‐specific curves for average stature individuals. The resulting curves demonstrate very slow weight gain in the first 2 years. Short stature is seen in many, but after age 4 years the 95th centile for height falls within the low normal range for average stature children. Head circumference curves largely overlap those for average stature, reflecting relative macrocephaly. © 2012 Wiley Periodicals, Inc.
SNP array and phenotype correlation shows that FLI1 deletion per se is not responsible for thrombocytopenia development in Jacobsen syndrome
Authors: Trkova Marie , Becvarova Vera , Hynek Martin , Hnykova Lenka , Hlavova Eva , Kreckova Gabriela , Kulovany Eduard , Cutka David , Zatloukalova Jitka , Markova Kristyna , Sukova Martina , Horacek Jiri , Stejskal David
Published: August 2012

Jacobsen syndrome (JBS) is a rare chromosomal disorder caused by terminal deletion of the long arm of chromosome 11. We report on four prenatally diagnosed patients with JBS with variable prenatal and postnatal phenotypes and 11q deletions of varying sizes. Precise characterization of the deleted region in three patients was performed by SNP arrays. The severity of both the prenatal and postnatal phenotypes did not correlate with the size of the haploinsufficient region. Despite the large difference in the deletion size (nearly 6 Mb), both of the live‐born patients had similar phenotypes corresponding to JBS. However, one of the most prominent features of JBS, thrombocytopenia, was only present in the live‐born boy. The girl, who had a significantly longer deletion spanning all four genes suspected of being causative of JBS‐related thrombocytopenia (FLI1, ETS1, NFRKB, and JAM3), did not manifest a platelet phenotype. Therefore, our findings do not support the traditional view of deletion size correlation in JBS or the causative role of FLI1, ETS1, NFRKB, and JAM3 deletion per se for the development of disease‐related thrombocytopenia. © 2012 Wiley Periodicals, Inc.
Assessment of bone mineral status in children with Marfan syndrome
Authors: Grover Monica , Brunetti‐Pierri Nicola , Belmont John , Phan Kelly , Tran Alyssa , Shypailo Roman J. , Ellis Kenneth J. , Lee Brendan H.
Published: August 2012

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with skeletal involvement. It is caused by mutations in fibrillin1 (FBN1) gene resulting in activation of TGF‐β, which developmentally regulates bone mass and matrix properties. There is no consensus regarding bone mineralization in children with MFS. Using dual‐energy X‐ray absorptiometry (DXA), we evaluated bone mineralization in 20 children with MFS unselected for bone problems. z‐Scores were calculated based on age, gender, height, and ethnicity matched controls. Mean whole body bone mineral content (BMC) z‐score was 0.26 ± 1.42 (P = 0.41). Mean bone mineral density (BMD) z‐score for whole body was −0.34 ± 1.4 (P = 0.29) and lumbar spine was reduced at −0.55 ± 1.34 (P = 0.017). On further adjusting for stature, which is usually higher in MFS, mean BMC z‐score was reduced at −0.677 ± 1.37 (P = 0.04), mean BMD z‐score for whole body was −0.82 ± 1.55 (P = 0.002) and for lumbar spine was −0.83 ± 1.32 (P = 0.001). An increased risk of osteoporosis in MFS is controversial. DXA has limitations in large skeletons because it tends to overestimate BMD and BMC. By adjusting results for height, age, gender, and ethnicity, we found that MFS patients have significantly lower BMC and BMD in whole body and lumbar spine. Evaluation of diet, exercise, vitamin D status, and bone turnover markers will help gain insight into pathogenesis of the reduced bone mass. Further, larger longitudinal studies are required to evaluate the natural history, incidence of fractures, and effects of pharmacological therapy. © 2012 Wiley Periodicals, Inc.
Expression analysis of a 17p terminal deletion, including YWHAE, but not PAFAH1B1, associated with normal brain structure on MRI in a young girl
Authors: Enomoto Keisuke , Kishitani Yasuhiro , Tominaga Makiko , Ishikawa Aki , Furuya Noritaka , Aida Noriko , Masuno Mitsuo , Yamada Ken‐Ichiro , Kurosawa Kenji
Published: August 2012

Tyrosine 3‐monooxygenase/tryptophan 5‐monooxygenase activation protein, epsilon polypeptide (YWHAE), on chromosome 17p13.3, has been shown to play a crucial role in neuronal development. The deletion of YWHAE, but not platelet‐activating factor acetylhydrolase, isoform 1b, subunit 1 (PAFAH1B1), underlies a newly recognized neurodevelopmental disorder, characterized by significant growth retardation, developmental delay/intellectual disability (DD/ID), distinctive facial appearance, and brain abnormalities. Here, we report on a girl with a terminal deletion of 17p13.3, including YWHAE but not PAFAH1B1, showing normal brain structure on MRI. She had mild developmental delay, a distinctive facial appearance, and severe growth retardation despite normal growth hormone levels, which was improved by growth hormone therapy. Expression analysis of YWHAE and PAFAH1B1 yielded results consistent with array CGH and FISH results. These results indicate that the dosage effect of YWHAE varies from severe to very mild structural brain abnormalities, and suggest that the expression of YWHAE is associated with a complex mechanism of neuronal development. © 2012 Wiley Periodicals, Inc.
Outcomes of endoscopy and computed tomography in patients with chronic rhinosinusitis
Authors: Amine Muhamad , Lininger Lauren , Fargo Keith N. , Welch Kevin C.
Published: August 2012

Background:

Chronic rhinosinusitis (CRS) is a common disease diagnosed based on a combination of symptoms, imaging, and/or endoscopy. Computed tomography (CT) is the gold standard in diagnosis of CRS due to inherent low sensitivity of endoscopy. We sought to assess the correlation between symptoms, endoscopy, and imaging in order to reduce the number of CTs without decreasing diagnostic accuracy.

Methods:

Retrospective review of a single practitioner's patients from 2008 to 2010 who presented for evaluation of CRS. Data on demographics, symptoms, and endoscopic and CT findings were collected and analyzed. Exclusion criteria included patients with prior surgery, no imaging, and those that failed to meet the 2007 CRS Task Force symptom criteria.

Results:

A total of 244 patients met the Task Force symptom criteria. Using CT as the gold standard, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of endoscopy alone was 36%, 95%, 89%, and 55%, respectively. The number of symptoms (NOS) strongly correlated with the absence or presence of disease (p < 0.01). Incorporating NOS into a CRS diagnostic algorithm improved sensitivity and NPV of nasal endoscopy to 82% and 79% while maintaining its specificity and PPV at 82% and 84%, respectively. Applying our algorithm retrospectively would have resulted in a reduction in the number of CTs by 69%, resulting in an acceptable 10% (n = 24/244) false negative rate and 8% (n = 20/244) false positive rate.

Conclusion:

Incorporating number of symptoms in a CRS diagnostic algorithm may drastically reduce the number of CTs needed. Clinical diagnostic accuracy is enhanced with this new algorithm while significantly reducing the cost and radiation burden of CTs. © 2013 ARS–AAOA, LLC.
Lumineszierende ionische Übergangsmetallkomplexe für leuchtende elektrochemische Zellen
Authors: Costa Rubén D. , Ortí Enrique , Bolink Henk J. , Monti Filippo , Accorsi Gianluca , Armaroli Nicola
Published: August 2012

Durch die Umsetzung neuer Beleuchtungskonzepte könnte die Verwertung von Energie deutlich effizienter gestaltet werden. Alle derzeit entwickelten Technologien beruhen auf elektrolumineszierenden Festkörpern und lassen sich allgemein als Festkörperbeleuchtung (solid‐state lighting, SSL) einstufen. Die beiden wichtigsten Zweige der SSL‐Technologie sind Leuchtdioden (LEDs) und organische Leuchtdioden (OLEDs), doch seit kurzem bilden auch leuchtende elektrochemische Zellen (LECs) eine Alternative, die als aktive Materialien entweder lumineszierende Polymere in Kombination mit ionischen Salzen oder lumineszierende ionische Spezies wie ionische Übergangsmetallkomplexe (iTMCs) enthalten. Cyclometallierte IrIII‐Komplexe werden bei weitem am häufigsten als iTMCs in LECs verwendet. Hier zeigen wir, wie diese Komplexe hergestellt werden können, und wir diskutieren ihre einzigartigen elektronischen, photophysikalischen und photochemischen Eigenschaften. Schließlich werden die wichtigsten Fortschritte bezüglich Einschaltzeit, Stabilität, Effizienz und Farbe von iTMCs‐LECs präsentiert.
Synthesis and Antimicrobial Activity of Novel Heterocyclic Sulfamoyl‐phenyl‐carboximidamides Derived from Clinically Applied Sulfonamides
Authors: Gobis Katarzyna , Foks Henryk , Wiśniewska Katarzyna , Dąbrowska‐Szponar Maria , Augustynowicz‐Kopeć Ewa , Napiórkowska Agnieszka
Published: August 2012

A series of novel heterocyclic sulfamoyl‐phenyl‐carboximidamides were synthesized in satisfactory yields via condensation of clinically applied sulfonamides with heterocyclic methyl carbimidates. New structures were confirmed by IR and NMR spectra as well as elemental analyses. All the compounds were screened for their antibacterial, antifungal, and tuberculostatic activities. Preliminary results indicated that some target compounds exhibited promising antibacterial potency. Especially, N‐[4‐(thiazol‐2‐sulfamoyl)phenyl]pyrazine‐2‐carboximidamide (16) was found to be as potent as clinically applied sulfamethoxypyridazine.
Reagent‐Based DOS: Developing a Diastereoselective Methodology to Access Spirocyclic‐ and Fused Heterocyclic Ring Systems
Authors: Damerla V. Surendra Babu , Tulluri Chiranjeevi , Gundla Rambabu , Naviri Lava , Adepally Uma , Iyer Pravin S. , Murthy Y. L. N. , Prabhakar Nampally , Sen Subhabrata
Published: August 2012

Herein, we report a diversity‐oriented‐synthesis (DOS) approach for the synthesis of biologically relevant molecular scaffolds. Our methodology enables the facile synthesis of fused N‐heterocycles, spirooxoindolones, tetrahydroquinolines, and fused N‐heterocycles. The two‐step sequence starts with a chiral‐bicyclic‐lactam‐directed enolate‐addition/substitution step. This step is followed by a ring‐closure onto the built‐in scaffold electrophile, thereby leading to stereoselective carbocycle‐ and spirocycle‐formation. We used in silico tools to calibrate our compounds with respect to chemical diversity and selected drug‐like properties. We evaluated the biological significance of our scaffolds by screening them in two cancer cell‐lines. In summary, our DOS methodology affords new, diverse scaffolds, thereby resulting in compounds that may have significance in medicinal chemistry.
Einfluss des Klebstoffes auf das Brandverhalten von Brettschichtholz
Authors: Klippel Michael , Frangi Andrea
Published: August 2012

Die Verwendung von Klebstoffen für die Herstellung von Holzprodukten ist im konstruktiven Holzbau unerlässlich. Die Tragsicherheit von verklebten tragenden Holzbauteilen wie Brettschichtholz wird durch das Verhalten der eingesetzten Klebstoffe maßgeblich beeinflusst. Klebstoffe müssen eine zuverlässige Festigkeit und Dauerhaftigkeit aufweisen, so dass sie unter der vorgesehenen Nutzung ihre Funktionsfähigkeit vollständig behalten. Diese Leistungsanforderung muss auch im Brandfall sichergestellt sein. Zur Untersuchung des Einflusses des Klebstoffes auf das Tragverhalten von Brettschichtholz im Brandfall wurden umfangreiche Untersuchungen durchgeführt. Der vorliegende Artikel fasst die wesentlichen Resultate und Erkenntnisse dieser Untersuchungen zusammen. Die Untersuchungen zeigten den Einfluss des Klebstoffes auf das Tragverhalten bei Brettschichtholz im Brandfall. Bei der flächigen Verklebung (zwischen den Brettlamellen) zeigte sich anhand numerischer Untersuchungen, dass ein Versagen in der Klebstofffuge auch mit Klebstoffen mit geringer thermischer Stabilität kaum maßgebend wird. Die Brandversuche an keilgezinkten Brettschichtholzlamellen zeigten, dass der Feuerwiderstand von der Versagensart dominiert wird. Unter Berücksichtigung der beobachteten Bruchbilder ließen sich keine signifikanten Unterschiede zwischen den geprüften Klebstoffen feststellen.

Influence of the adhesive on the fire behaviour of glued laminated timber. Adhesives are commonly used to produce engineered wood products such as glued laminated timber beams. The load‐bearing capacity of these structural timber elements is strongly influenced by the adhesive used. As a consequence, adhesives have to meet requirements regarding strength and durability to ensure the functionality of structural timber elements during the whole lifetime. Also during fire, the performance requirements have to be fulfilled for a certain time period. To investigate the influence of the adhesive on the load‐carrying capacity of glued laminated timber in fire, comprehensive analysis has been performed. This article summarises the most important results and findings. Based on the numerical analysis performed to investigate the influence of adhesive in the bondline between two lamellas, it can be concluded that also if the adhesive strength in the bondline is strongly influenced by the temperature, in most common design applications failure will occur because the bending resistance of the beam is exceeded. Failure in the bondline is hardly to be expected. The fire tests on finger‐jointed timber boards showed that the fire resistance is dominated by the type of failure. Taking into account the different failure modes, no significant difference was observed between the adhesives studied.
Untersuchung des Gesamtenergiedurchlassgrades an gebäudeintegrierbaren, teiltransparenten Photovoltaik‐Modulen bei elektrischer Leistungsentnahme
Authors: Schäfle Claudia , Feldmeier Franz
Published: August 2012

Der Gesamtenergiedurchlassgrad (g‐Wert) verschiedener teiltransparenter, gebäudeintegrierbarer Photovoltaik‐Module wurde mit und ohne Entnahme elektrischer Leistung kalorimetrisch gemessen. Durch die Leistungsentnahme sinkt die Oberflächentemperatur des Moduls um bis zu 4 K. Gleichzeitig reduziert sich der g‐Wert aufgrund der geringeren sekundären Wärmeabgabe. Die Größe der Abnahme hängt von der entnommenen Leistung ab und stimmt sehr gut mit einem einfachen, auf dem Energiesatz basierenden Rechenmodell überein.

Investigation of the total solar energy transmittance on building‐integrated, semitransparent photovoltaic modules with and without extraction of electrical power. The total solar energy transmittance (g‐value) of different building‐integrated PV‐elements has been measured with and without extracting electrical power from the module. When extracting energy, a reduction in the g‐value has been measured. Moreover, a reduction in temperature up to 4 K on the inner surface is observed. The experimental results are in very good agreement with a physical model based on energy conservation.
Untersuchungen zu Wärmeleitfähigkeit und Feuchteverhalten von Holzfaserplatten und Materialkombinationen
Authors: Brombacher Volker , Michel Franco , Niemz Peter , Volkmer Thomas
Published: August 2012

In der vorliegenden Arbeit wurden wesentliche thermische und hygroskopische Kennwerte von Holzfaserplatten ermittelt. Für die Untersuchungen wurden aktuelle Produkte einzeln oder in Kombination analysiert. Ergänzend wurden Produkte auf Hanf‐ und mineralischer Basis in die Untersuchungen mit einbezogen. Die Bestimmung der Wärmeleitfähigkeit, der Sorptionsgeschwindigkeit sowie des Quell‐ und Schwindverhaltens erfolgte entsprechend den geltenden Normen. In Bezug auf die thermischen Eigenschaften ergibt sich für die verschiedenen Dichtebereiche eine Abhängigkeit zwischen Rohdichte und Wärmeleitfähigkeit, welche jedoch unterschiedlich stark ausgeprägt ist. Bei den Materialkombinationen zeigt sich der dominierende Einfluss der Rohdichte der äußeren Schichten, wobei leichte Materialen zu einer niedrigeren Wärmeleitung führen. Das Dampfdiffusionsverhalten wird durch das Herstellungsverfahren der Platten beeinflusst, darüber hinaus ist teilweise ein Einfluss der Probendicke zu erkennen. Die Sorptionskurven für den Be‐ und Entfeuchtungsprozess zeigen erwartungsgemäß den bekannten Hysterese Effekt des Holzes. Die Sorptionsgeschwindigkeiten für die untersuchten Materialien variieren deutlich, jedoch ist ein Einfluss der Schichtdicke nachweisbar. Die Dickenquellung ist deutlich größer als die Quellung in Plattenebene. Die Herstellungsrichtung wirkt sich dabei nur geringfügig auf die Messwerte aus.

Investigation of thermal conductivity and moisture behaviour of fibreboard and material combinations. In the presented paper relevant thermal and hygroscopic parameters of wood fiberboards were determined. The investigations were conducted on up to date products in a single state or in combination. Furthermore materials based on hemp and mineral fibers were included in the investigations. The determination of the thermal conductivity, the sorption behavior, swelling and shrinkage was done in accordance to the actual standards. Concerning the thermal behavior a correlation between density and thermal conductivity was obvious, but different significant for the several density groups. For the material combination the density of the outer layers dominates the thermal parameters, respectively at this position light material leads to low thermal conductivity. The vapor diffusion gets influence by the production process of the single materials. The thickness of the boards tends to influence the vapor resistance as well. The sorption curves for de‐ and adsorption show the expected hysteresis like for solid wood. But the sorption speed varies clearly for the different materials. The swelling perpendicular to the panel plane is significant higher than in plane. The production direction has a little influence in the swelling behavior only.
Semiparametric transformation models for current status data with informative censoring
Authors: Chen Chyong‐Mei , Lu Tai‐Fang C. , Chen Man‐Hua , Hsu Chao‐Min
Published: August 2012

Current status data arise due to only one feasible examination such that the failure time of interest occurs before or after the examination time. If the examination time is intrinsically related to the failure time of interest, the examination time is referred to as an informative censoring time. Such data may occur in many fields, for example, epidemiological surveys and animal carcinogenicity experiments. To avoid severely misleading inferences resulted from ignoring informative censoring, we propose a class of semiparametric transformation models with log‐normal frailty for current status data with informative censoring. A shared frailty is used to account for the correlation between the failure time and censoring time. The expectation‐maximization (EM) algorithm combining a sieve method for approximating an infinite‐dimensional parameter is employed to estimate all parameters. To investigate finite sample properties of the proposed method, simulation studies are conducted, and a data set from a rodent tumorigenicity experiment is analyzed for illustrative purposes.
Analysis of multivariate recurrent event data with time‐dependent covariates and informative censoring
Authors: Zhao Xingqiu , Liu Li , Liu Yanyan , Xu Wei
Published: August 2012

Multivariate recurrent event data are usually encountered in many clinical and longitudinal studies in which each study subject may experience multiple recurrent events. For the analysis of such data, most existing approaches have been proposed under the assumption that the censoring times are noninformative, which may not be true especially when the observation of recurrent events is terminated by a failure event. In this article, we consider regression analysis of multivariate recurrent event data with both time‐dependent and time‐independent covariates where the censoring times and the recurrent event process are allowed to be correlated via a frailty. The proposed joint model is flexible where both the distributions of censoring and frailty variables are left unspecified. We propose a pairwise pseudolikelihood approach and an estimating equation‐based approach for estimating coefficients of time‐dependent and time‐independent covariates, respectively. The large sample properties of the proposed estimates are established, while the finite‐sample properties are demonstrated by simulation studies. The proposed methods are applied to the analysis of a set of bivariate recurrent event data from a study of platelet transfusion reactions.
Development of a Saccharomyces cerevisiae strain for increasing the accumulation of triacylglycerol as a microbial oil feedstock for biodiesel production using glycerol as a substrate
Authors: Yu Kyung Ok , Jung Ju , Ramzi Ahmad Bazli , Choe Se Hoon , Kim Seung Wook , Park Chulhwan , Han Sung Ok
Published: August 2012

Triacylglycerol (TAG) is a microbial oil feedstock for biodiesel production that uses an inexpensive substrate, such as glycerol. Here, we demonstrated the overproduction of TAG from glycerol in engineered Saccharomyces cerevisiae via the glycerol‐3‐phosphate (G3P) pathway by overexpressing the major TAG synthesis. The G3P accumulation was increased 2.4‐fold with the increased glycerol utilization gained by the overexpression of glycerol kinase (GUT1). By overexpressing diacylglycerol acyltransferase (DGA1) and phospholipid diacylglycerol acyltransferase (LRO1), the engineered YPH499 (pGutDgaLro1) strain produced 23.0 mg/L lipids, whereas the YPH499 (pESC‐TRP) strain produced 6.2 mg/L total lipids and showed a lipid content that was increased 1.4‐fold compared with 3.6% for the wild‐type strain after 96 h of cultivation. After 96 h of cultivation using glycerol, the overall content of TAG in the engineered strain, YPH499 (pGutDgaLro1), yielded 8.2% TAG, representing a 2.3‐fold improvement, compared with 3.6% for the wild‐type strain. The results should allow a reduction of costs and a more sustainable production of biodiesel. Biotechnol. Bioeng. 2013; 110: 343–347. © 2012 Wiley Periodicals, Inc.
Critical review of activated sludge modeling: State of process knowledge, modeling concepts, and limitations
Authors: Hauduc H. , Rieger L. , Oehmen A. , van Loosdrecht M.C.M. , Comeau Y. , Héduit A. , Vanrolleghem P.A. , Gillot S.
Published: August 2012

This work critically reviews modeling concepts for standard activated sludge wastewater treatment processes (e.g., hydrolysis, growth and decay of organisms, etc.) for some of the most commonly used models. Based on a short overview on the theoretical biochemistry knowledge this review should help model users to better understand (i) the model concepts used; (ii) the differences between models, and (iii) the limits of the models. The seven analyzed models are: (1) ASM1; (2) ASM2d; (3) ASM3; (4) ASM3 + BioP; (5) ASM2d + TUD; (6) Barker & Dold model; and (7) UCTPHO+. Nine standard processes are distinguished and discussed in the present work: hydrolysis; fermentation; ordinary heterotrophic organisms (OHO) growth; autotrophic nitrifying organisms (ANO) growth; OHO & ANO decay; poly‐hydroxyalkanoates (PHA) storage; polyphosphate (polyP) storage; phosphorus accumulating organisms PAO) growth; and PAO decay. For a structured comparison, a new schematic representation of these processes is proposed. Each process is represented as a reaction with consumed components on the left of the figure and produced components on the right. Standardized icons, based on shapes and color codes, enable the representation of the stoichiometric modeling concepts and kinetics. This representation allows highlighting the conceptual differences of the models, and the level of simplification between the concepts and the theoretical knowledge. The model selection depending on their theoretical limitations and the main research needs to increase the model quality are finally discussed. Biotechnol. Bioeng. 2013; 110: 24–46. © 2012 Wiley Periodicals, Inc.
Methanol‐driven enhanced biological phosphorus removal with a syntrophic consortium
Authors: Tayà Carlota , Guerrero Javier , Vanneste Gianni , Guisasola Albert , Baeza Juan A.
Published: August 2012

The presence of suitable carbon sources for enhanced biological phosphorus removal (EBPR) plays a key role in phosphorus removal from wastewater in urban WWTP. For wastewaters with low volatile fatty acids (VFAs) content, an external carbon addition is necessary. As methanol is the most commonly external carbon source used for denitrification it could be a priori a promising alternative, but previous attempts to use it for EBPR have failed. This study is the first successful report of methanol utilization as external carbon source for EBPR. Since a direct replacement strategy (i.e., supply of methanol as a sole carbon source to a propionic‐fed PAO‐enriched sludge) failed, a novel process was designed and implemented successfully: development of a consortium with anaerobic biomass and polyphosphate accumulating organisms (PAOs). Methanol‐degrading acetogens were (i) selected against other anaerobic methanol degraders from an anaerobic sludge; (ii) subjected to conventional EBPR conditions (anaerobic + aerobic); and (iii) bioaugmented with PAOs. EBPR with methanol as a sole carbon source was sustained in a mid‐term basis with this procedure. Biotechnol. Bioeng. 2013; 110: 391–400. © 2012 Wiley Periodicals, Inc.
Micropatterned polyelectrolyte nanofilms promote alignment and myogenic differentiation of C2C12 cells in standard growth media
Authors: Palamà Ilaria E. , D'Amone Stefania , Coluccia Addolorata M.L. , Gigli Giuseppe
Published: August 2012

Alignment of skeletal myoblasts is considered a critical step during myotube formation. The C2C12 cell line is frequently used as a model of skeletal muscle differentiation that can be induced by lowering the serum concentration in standard culture flasks. In order to mimic the striated architectures of skeletal muscles in vitro, micro‐patterning techniques and surface engineering have been proven as useful approaches for promoting elongation and alignment of C2C12 myoblasts, thereby enhancing the outgrowth of multi‐nucleated myotubes upon switching from growth media (GM) to differentiative media (DM). Herein, a layer‐by‐layer (LbL) polyelectrolyte multilayer deposition was combined with a micro‐molding in capillaries (MIMIC) method to simultaneously provide biochemical and geometrical instructive cues that induced the formation of tightly apposed and parallel arrays of differentiating myotubes from C2C12 cells maintained in GM media for 15 days. This study focuses on two different types of patterned/self‐assembled nanofilms based on alternated layers of poly (allylamine hydrochloride) (PAH)/poly(sodium 4‐styrene‐sulfonate) (PSS) as biocompatible but not biodegradable polymeric structures, or poly‐L‐arginine sulfate salt (pARG)/dextran sulfate sodium salt (DXS) as both biocompatible and biodegradable surfaces. The influence of these microstructures as well as of the nanofilm composition on C2C12 skeletal muscle cells' differentiation and viability was evaluated and quantified, pointing to give a reference for skeletal muscle regenerative potential in culture conditions that do not promote it. At this regard, our results validate PEM microstructured devices, to a greater extent for (PAH/PSS)5‐coated microgrooves, as biocompatible and innovative tools for tissue engineering applications and molecular dissection of events controlling C2C12 skeletal muscle regeneration without switching to their optimal differentiative culture media in vitro. Biotechnol. Bioeng. 2013; 110: 586–596. © 2012 Wiley Periodicals, Inc.
Interactions between Clostridium beijerinckii and Geobacter metallireducens in co‐culture fermentation with anthrahydroquinone‐2, 6‐disulfonate (AH2QDS) for enhanced biohydrogen production from xylose
Authors: Zhang Xinyu , Ye Xiaofeng , Finneran Kevin T. , Zilles Julie L. , Morgenroth Eberhard
Published: August 2012

To enhance biohydrogen production, Clostridium beijerinckii was co‐cultured with Geobacter metallireducens in the presence of the reduced extracellular electron shuttle anthrahydroquinone‐2, 6‐disulfonate (AH2QDS). In the co‐culture system, increases of up to 52.3% for maximum cumulative hydrogen production, 38.4% for specific hydrogen production rate, 15.4% for substrate utilization rate, 39.0% for substrate utilization extent, and 34.8% for hydrogen molar yield in co‐culture fermentation were observed compared to a pure culture of C. beijerinckii without AH2QDS. G. metallireducens grew in the co‐culture system, resulting in a decrease in acetate concentration under co‐culture conditions and a presumed regeneration of AH2QDS from AQDS. These co‐culture results demonstrate metabolic crosstalk between the fermentative bacterium C. beijerinckii and the respiratory bacterium G. metallireducens and suggest a strategy for industrial biohydrogen production. Biotechnol. Bioeng. 2013; 110: 164–172. © 2012 Wiley Periodicals, Inc.
Photoautotrophic cathodic oxygen reduction catalyzed by a green alga, Chlamydomonas reinhardtii
Authors: Liu Xian‐Wei , Sun Xue‐Fei , Huang Yu‐Xi , Li Dao‐Bo , Zeng Raymond J. , Xiong Lu , Sheng Guo‐Ping , Li Wen‐Wei , Cheng Yuan‐Yuan , Wang Shu‐Guang , Yu Han‐Qing
Published: August 2012

Biofuel cells (BFCs) use enzymes and microbial cells to produce energy from bioavailable substrates and treat various wastewaters, and cathodic oxygen reduction is a key factor governing the efficiency of BFCs. In this study, we demonstrated that a green alga, Chlamydomonas reinhardtii, could directly mediate oxygen reduction. Cyclic voltammogram analysis revealed that the C. reinhardtii biofilm formed on a solid electrode was responsible for oxygen reduction without dosing of electron mediator. Furthermore, 4‐electron oxygen reduction pathway was found in this self‐sustained, light‐responded BFC. The results of this study could expand our understanding and viewpoints of biocathode catalysis, which is essential for novel catalyst design and development for BFCs. Biotechnol. Bioeng. 2013; 110: 173–179. © 2012 Wiley Periodicals, Inc.
Shear‐induced detachment of biofilms from hollow fiber silicone membranes
Authors: Huang Z. , McLamore E.S. , Chuang H.S. , Zhang W. , Wereley S. , Leon J.L.C. , Banks M.K.
Published: August 2012

A suite of techniques was utilized to evaluate the correlation between biofilm physiology, fluid‐induced shear stress, and detachment in hollow fiber membrane aerated bioreactors. Two monoculture species biofilms were grown on silicone fibers in a hollow fiber membrane aerated bioreactors (HfMBR) to assess detachment under laminar fluid flow conditions. Both physiology (biofilm thickness and roughness) and nutrient mass transport data indicated the presence of a steady state mature biofilm after 3 weeks of development. Surface shear stress proved to be an important parameter for predicting passive detachment for the two biofilms. The average shear stress at the surface of Nitrosomonas europaea biofilms (54.5 ± 3.2 mPa) was approximately 20% higher than for Pseudomonas aeruginosa biofilms (45.8 ± 7.7 mPa), resulting in higher biomass detachment. No significant difference in shear stress was measured between immature and mature biofilms of the same species. There was a significant difference in detached biomass for immature vs. mature biofilms in both species. However, there was no difference in detachment rate between the two species. Biotechnol. Bioeng. 2013; 110: 525–534. © 2012 Wiley Periodicals, Inc.
Engineering of recombinant E. coli cells co‐expressing P450pyrTM monooxygenase and glucose dehydrogenase for highly regio‐ and stereoselective hydroxylation of alicycles with cofactor recycling
Authors: Pham Son Q. , Gao Pengfei , Li Zhi
Published: August 2012

E. coli (P450pyrTM‐GDH) with dual plasmids, pETDuet containing P450pyr triple mutant I83H/M305Q/A77S (P450pyrTM) and ferredoxin reductase (FdR) genes and pRSFDuet containing glucose dehydrogenase (GDH) and ferredoxin (Fdx) genes, was engineered to show a high activity (12.7 U g−1 cdw) for the biohydroxylation of N‐benzylpyrrolidine 1 and a GDH activity of 106 U g−1 protein. The E. coli cells were used as efficient biocatalysts for highly regio‐ and stereoselective hydroxylation of alicyclic substrates at non‐activated carbon atom with enhanced productivity via intracellular recycling of NAD(P)H. Hydroxylation of N‐benzylpyrrolidine 1 with resting cells in the presence of glucose showed excellent regio‐ and stereoselectivity, giving (S)‐N‐benzyl‐3‐hydroxypyrrolidine 2 in 98% ee as the sole product in 9.8 mM. The productivity is much higher than that of the same biohydroxylation using E. coli (P450pyrTM)b without expressing GDH. E. coli (P450pyrTM‐GDH) was found to be highly regio‐ and stereoselective for the hydroxylation of N‐benzylpyrrolidin‐2‐one 3, improving the regioselectivity from 90% of the wild‐type P450pyr to 100% and giving (S)‐N‐benzyl‐4‐hydroxylpyrrolidin‐2‐one 4 in 99% ee as the sole product. A high activity of 15.5 U g−1 cdw was achieved and (S)‐4 was obtained in 19.4 mM. E. coli (P450pyrTM‐GDH) was also found to be highly regio‐ and stereoselective for the hydroxylation of N‐benzylpiperidin‐2‐one 5, increasing the ee of the product (S)‐N‐benzyl‐4‐hydroxy‐piperidin‐2‐one 6 to 94% from 33% of the wild‐type P450pyr. A high activity of 15.8 U g−1 cdw was obtained and (S)‐6 was produced in 3.3 mM as the sole product. E. coli (P450pyrTM‐GDH) represents the most productive system known thus far for P450‐catalyzed hydroxylations with cofactor recycling, and the hydroxylations with E. coli (P450pyrTM‐GDH) provide with simple and useful syntheses of (S)‐2, (S)‐4, and (S)‐6 that are valuable pharmaceutical intermediates and difficult to prepare. Biotechnol. Bioeng. 2013; 110: 363–373. © 2012 Wiley Periodicals, Inc.
A system of miniaturized stirred bioreactors for parallel continuous cultivation of yeast with online measurement of dissolved oxygen and off‐gas
Authors: Klein Tobias , Schneider Konstantin , Heinzle Elmar
Published: August 2012

Chemostat cultivation is a powerful tool for physiological studies of microorganisms. We report the construction and application of a set of eight parallel small‐scale bioreactors with a working volume of 10 mL for continuous cultivation. Hungate tubes were used as culture vessels connected to multichannel‐peristaltic pumps for feeding fresh media and removal of culture broth and off‐gas. Water saturated air is sucked into the bioreactors by applying negative pressure, and small stirrer bars inside the culture vessels allow sufficient mixing and oxygen transfer. Optical sensors are used for non‐invasive online measurement of dissolved oxygen, which proved to be a powerful indicator of the physiological state of the cultures, particularly of steady‐state conditions. Analysis of culture exhaust‐gas by means of mass spectrometry enables balancing of carbon. The capacity of the developed small‐scale bioreactor system was validated using the fission yeast Schizosaccharomyces pombe, focusing on the metabolic shift from respiratory to respiro‐fermentative metabolism, as well as studies on consumption of different substrates such as glucose, fructose, and gluconate. In all cases, an almost completely closed carbon balance was obtained proving the reliability of the experimental setup. Biotechnol. Bioeng. 2013; 110: 535–542. © 2012 Wiley Periodicals, Inc.
Chemometrics applications in biotechnology processes: Predicting column integrity and impurity clearance during reuse of chromatography resin
Authors: Rathore Anurag S. , Mittal Shachi , Lute Scott , Brorson Kurt
Published: August 2012

Separation media, in particular chromatography media, is typically one of the major contributors to the cost of goods for production of a biotechnology therapeutic. To be cost‐effective, it is industry practice that media be reused over several cycles before being discarded. The traditional approach for estimating the number of cycles a particular media can be reused for involves performing laboratory scale experiments that monitor column performance and carryover. This dataset is then used to predict the number of cycles the media can be used at manufacturing scale (concurrent validation). Although, well accepted and widely practiced, there are challenges associated with extrapolating the laboratory scale data to manufacturing scale due to differences that may exist across scales. Factors that may be different include: level of impurities in the feed material, lot to lot variability in feedstock impurities, design of the column housing unit with respect to cleanability, and homogeneity of the column packing. In view of these challenges, there is a need for approaches that may be able to predict column underperformance at the manufacturing scale over the product lifecycle. In case such an underperformance is predicted, the operators can unpack and repack the chromatography column beforehand and thus avoid batch loss. Chemometrics offers one such solution. In this article, we present an application of chemometrics toward the analysis of a set of chromatography profiles with the intention of predicting the various events of column underperformance including the backpressure buildup and inefficient deoxyribonucleic acid clearance. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012