bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalytic activity and autoprocessing of murine caspase-11 mediate noncanonical inflammasome assembly in response to cytosolic LPS
Authors: Akuma Daniel C , Wodzanowski Kimberly A , Schwartz Wertman Ronit , Exconde Patrick M , Vázquez Marrero Víctor R , Odunze Chukwuma E , Grubaugh Daniel , Shin Sunny , Taabazuing Cornelius , Brodsky Igor E
Published: January 2024

Inflammatory caspases are cysteine protease zymogens whose activation following infection or cellular damage occurs within supramolecular organizing centers (SMOCs) known as inflammasomes. Inflammasomes recruit caspases to undergo proximity-induced autoprocessing into an enzymatically active form that cleaves downstream targets. Binding of bacterial LPS to its cytosolic sensor, caspase-11 (Casp11), promotes Casp11 aggregation within a high-molecular-weight complex known as the noncanonical inflammasome, where it is activated to cleave gasdermin D and induce pyroptosis. However, the cellular correlates of Casp11 oligomerization and whether Casp11 forms an LPS-induced SMOC within cells remain unknown. Expression of fluorescently labeled Casp11 in macrophages revealed that cytosolic LPS induced Casp11 speck formation. Unexpectedly, catalytic activity and autoprocessing were required for Casp11 to form LPS-induced specks in macrophages. Furthermore, both catalytic activity and autoprocessing were required for Casp11 speck formation in an ectopic expression system, and processing of Casp11 via ectopically expressed TEV protease was sufficient to induce Casp11 speck formation. These data reveal a previously undescribed role for Casp11 catalytic activity and autoprocessing in noncanonical inflammasome assembly, and shed new light on the molecular requirements for noncanonical inflammasome assembly in response to cytosolic LPS.
Spatial transcriptomics in adult Drosophila reveals new cell types in the brain and identifies subcellular mRNA patterns in muscles
Authors: Janssens Jasper , Mangeol Pierre , Hecker Nikolai , Partel Gabriele , Spanier Katina , Ismail Joy , Hulselmans Gert , Aerts Stein , Schnorrer Frank
Published: January 2024

Recently, we have achieved a significant milestone with the creation of the Fly Cell Atlas. This single-nuclei atlas encompasses the entire fly, covering the entire head and body, in addition to all major organs. This atlas catalogs hundreds to thousands of cell types, of which we annotated 250. This still leaves many clusters to be fully characterized, in particular in the brain. Furthermore, with single-nuclei sequencing, all information about the spatial location of the cells and of the mRNAs within these cells is lost. Here, we provide a solution to this problem. In a proof of concept study, we have applied spatial transcriptomics using a selected gene panel to pinpoint the locations of 150 mRNA species in the adult fly. This enabled us to map unknown cell types identified in the Fly Cell Atlas to their spatial locations in the brain. Additionally, spatial transcriptomics discovered interesting principles of mRNA localization in large crowded muscle cells that may spark future mechanistic investigations. Furthermore, we present a set of computational tools that will allow for easier integration of spatial transcriptomics and single-cell datasets.
Revealing intact neuronal circuitry in centimeter-sized formalin-fixed paraffin-embedded brain
Authors: Lin Ya-Hui , Wang Li-Wen , Chen Yen-Hui , Chan Yi-Chieh , Hu Shang-Hsiu , Wu Sheng-Yan , Chiang Chi-Shiun , Huang Guan-Jie , Yang Shang-Da , Chu Shi-Wei , Wang Kuo-Chuan , Lin Chin-Hsien , Huang Pei-Hsin , Cheng Hwai-Jong , Chen Bi-Chang , Chu Li-An
Published: January 2024

Tissue clearing and labeling techniques have revolutionized brain-wide imaging and analysis, yet their application to clinical formalin-fixed paraffin-embedded (FFPE) blocks remains challenging. We introduce MOCAT, a novel method for efficiently clearing and labeling centimeter-thick FFPE specimens using elevated temperature and concentrated detergents. MOCAT with multi-round immunolabeling reveals neuron circuitry regulating multiple neurotransmitter systems in a whole FFPE mouse brain, and is able to be used as the evaluation of disease treatment efficiency. MOCAT also supports expansion microscopy and can be performed on a non-sectioned 15-year-old FFPE specimen. Thus, MOCAT represents a feasible approach for researching archived FFPE specimens for future neuroscientific and 3D neuropathological analyses.
Transcriptome-wide analysis of the function of Ded1 in translation preinitiation complex assembly in a reconstituted in vitro system
Authors: Zhou Fujun , Bocetti Julie M , Hou Meizhen , Qin Daoming , Hinnebusch Alan G , Lorsch Jon R
Published: January 2024

We have developed a deep sequencing-based approach, Rec-Seq, that allows simultaneous monitoring of ribosomal 48S preinitiation complex (PIC) formation on every mRNA in the translatome in an in vitro reconstituted system. Rec-Seq isolates key early steps in translation initiation in the absence of all other cellular components and processes. Using this approach, we show that the DEAD-box ATPase Ded1 promotes 48S PIC formation on the start codons of >1000 native mRNAs, most of which have long, structured 5′-untranslated regions (5′UTRs). Remarkably, initiation measured in Rec-Seq was enhanced by Ded1 for most mRNAs previously shown to be highly Ded1-dependent by ribosome profiling of ded1 mutants in vivo, demonstrating that the core translation functions of the factor are recapitulated in the purified system. Our data do not support a model in which Ded1acts by reducing initiation at alternative start codons in 5′UTRs and instead indicate it functions by directly promoting mRNA recruitment to the 43S PIC and scanning to locate the main start codon. We also provide evidence that eIF4A, another essential DEAD-box initiation factor, is required for efficient PIC assembly on almost all mRNAs, regardless of their structural complexity, in contrast to the preferential stimulation by Ded1 of initiation on mRNAs with long, structured 5′UTRs.
Transcriptome-wide analysis of the function of Ded1 in translation preinitiation complex assembly in a reconstituted in vitro system
Authors: Zhou Fujun , Bocetti Julie M. , Hou Meizhen , Qin Daoming , Hinnebusch Alan G. , Lorsch Jon R.
Published: January 2024

We have developed a deep sequencing-based approach, Rec-Seq, that allows simultaneous monitoring of ribosomal 48S pre-initiation complex (PIC) formation on every mRNA in the translatome in an in vitro reconstituted system. Rec-Seq isolates key early steps in translation initiation in the absence of all other cellular components and processes. Using this approach we show that the DEAD-box ATPase Ded1 promotes 48S PIC formation on the start codons of >1000 native mRNAs, most of which have long, structured 5’-untranslated regions (5’UTRs). Remarkably, initiation measured in Rec-Seq was enhanced by Ded1 for most mRNAs previously shown to be highly Ded1-dependent by ribosome profiling of
ded1
mutants in vivo, demonstrating that the core translation functions of the factor are recapitulated in the purified system. Our data do not support a model in which Ded1acts by reducing initiation at start codons in 5’UTRs and instead indicate it functions by directly promoting mRNA recruitment to the 43S PIC and scanning to locate the start codon. We also provide evidence that eIF4A, another essential DEAD-box initiation factor, is required for efficient PIC assembly on almost all mRNAs, regardless of their structural complexity, in contrast to the preferential stimulation by Ded1 of initiation on mRNAs with long, structured 5’UTRs.
Specific and comprehensive genetic targeting reveals brain-wide distribution and synaptic input patterns of GABAergic axo-axonic interneurons
Authors: Raudales Ricardo , Kim Gukhan , Kelly Sean M. , Hatfield Joshua , Guan Wuqiang , Zhao Shengli , Paul Anirban , Qian Yongjun , Li Bo , Huang Z. Josh
Published: January 2024

Axo-axonic cells (AACs), also called chandelier cells (ChCs) in the cerebral cortex, are the most distinctive type of GABAergic interneurons described in the neocortex, hippocampus, and basolateral amygdala (BLA). AACs selectively innervate glutamatergic projection neurons (PNs) at their axon initial segment (AIS), thus may exert decisive control over PN spiking and regulate PN functional ensembles. However, the brain-wide distribution, synaptic connectivity, and circuit function of AACs remains poorly understood, largely due to the lack of specific and reliable experimental tools. Here, we have established an intersectional genetic strategy that achieves specific and comprehensive targeting of AACs throughout the mouse brain based on their lineage (
Nkx2.1
) and molecular (
Unc5b
,
Pthlh
) markers. We discovered that AACs are deployed across essentially all the pallium-derived brain structures, including not only the dorsal pallium-derived neocortex and medial pallium-derived hippocampal formation, but also the lateral pallium-derived claustrum-insular complex, and the ventral pallium-derived extended amygdaloid complex and olfactory centers. AACs are also abundant in anterior olfactory nucleus, taenia tecta and lateral septum. AACs show characteristic variations in density across neocortical areas and layers and across subregions of the hippocampal formation. Neocortical AACs comprise multiple laminar subtypes with distinct dendritic and axonal arborization patterns. Retrograde monosynaptic tracing from AACs across neocortical, hippocampal and BLA regions reveal shared as well as distinct patterns of synaptic input. Specific and comprehensive targeting of AACs facilitates the study of their developmental genetic program and circuit function across brain structures, providing a ground truth platform for understanding the conservation and variation of a bona fide cell type across brain regions and species.
An empirical study of software ecosystem related tweets by npm maintainers
Authors: Islam Syful , Nugroho Yusuf Sulistyo , Shahrear Chy. Md. , Wahed Nuhash , Gunawan Dedi , Wahyu Pamungkas Endang , Humayun Kabir Mohammed , Indra Kurniawan Yogiek , Uddin Md. Kamal
Published: January 2024

The npm ecosystem is crucial for the JavaScript community and its development is significantly influenced by the opinions and feedback of npm maintainers. Many software ecosystem maintainers have utilized social media, such as Twitter, to share community-related information and their views. However, the communication between npm maintainers via Twitter in terms of topics, nature, and sentiment have not been analyzed. This study conducts an empirical analysis of tweets by npm maintainers related to the software ecosystem to understand their perceptions and opinions better. A dataset of tweets was collected and analyzed using qualitative analysis techniques to identify the topic of tweets, nature, and their sentiments. Our study demonstrates that most tweets belong to the package management category, followed by notifications and community-related information. The most frequently discussed topics among npm maintainers in the package management category are usage scenarios. It appears that the nature of tweets mostly shared by npm maintainers is information, followed by question and answer, respectively. Additionally, the sentiment analysis reveals that npm maintainers express more positive sentiments towards notification and community-related discussion while expressing more neutral opinions towards the package management related discussion. This case study provides valuable insights into the perceptions and opinions of the npm maintainers regarding the software ecosystem and can inform future development and decision making.
Transcriptome analysis of green and purple fruited pepper provides insight into novel regulatory genes in anthocyanin biosynthesis
Authors: Tan Huaqiang , Li Liping , Tie Manman , Lu Ronghai , Pan Shaokun , Tang Youwan
Published: January 2024

Background

Pepper (Capsicum annuum L.) is a valuable horticultural crop with economic significance, and its purple fruit color is attributed to anthocyanin, a phytonutrient known for its health-promoting benefits. However, the mechanisms regulating anthocyanin biosynthesis in pepper have yet to be fully elucidated.

Methods

RNA sequencing (RNA-seq) was utilized to analyze the transcriptome of fruits from three purple-fruited varieties (HN191, HN192, and HN005) and one green-fruited variety (EJT) at various developmental stages. To determine the relationships between samples, Pearson correlation coefficients (PCC) and principal component analysis (PCA) were calculated. Differential expression analysis was performed using the DESeq2 package to identify genes that were expressed differently between two samples. Transcription factors (TF) were predicted using the iTAK program. Heatmaps of selected genes were generated using Tbtools software.

Results

The unripe fruits of HN191, HN192, and HN005, at the stages of 10, 20, and 30 days after anthesis (DAA), display a purple color, whereas the unripe fruits of variety EJT remain green. To understand the molecular basis of this color difference, five transcriptome comparisons between green and purple fruits were conducted: HN191-10 vs EJT-10, HN191-20 vs EJT-20, HN191-30 vs EJT-30, HN192-30 vs EJT-30, and HN005-30 vs EJT-30. Through this analysis, 503 common differentially expressed genes (DEGs) were identified. Among these DEGs, eight structural genes related to the anthocyanin biosynthesis pathway and 24 transcription factors (TFs) were detected. Notably, one structural gene (MSTRG.12525) and three TFs (T459_25295, T459_06113, T459_26036) exhibited expression patterns that suggest they may be novel candidate genes involved in anthocyanin biosynthesis. These results provide new insights into the regulation of anthocyanin biosynthesis in purple pepper fruit and suggest potential candidate genes for future genetic improvement of pepper germplasm with enhanced anthocyanin accumulation.
Prognostic significance of integrating total metabolic tumor volume and EGFR mutation status in patients with lung adenocarcinoma
Authors: Jiang Maoqing , Guo Xiuyu , Chen Ping , Zhang Xiaohui , Gao Qiaoling , Zhang Jingfeng , Zheng Jianjun
Published: January 2024

Background

The objective of this study was to investigate the prognostic significance of total metabolic tumor volume (TMTV) derived from baseline 18F-2-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT), in conjunction with epidermal growth factor receptor (EGFR) mutation status, among patients with lung adenocarcinoma (LUAD).

Methods

We performed a retrospective analysis on 141 patients with LUAD (74 males, 67 females, median age 67 (range 34–86)) who underwent 18F-FDG PET/CT and had their EGFR mutation status determined. Optimal cutoff points for TMTV were determined using time-dependent receiver operating characteristic curve analysis. The survival difference was compared using Cox regression analysis and Kaplan‒Meier curves.

Results

The EGFR mutant patients (n = 79, 56.0%) exhibited significantly higher 2-year progression-free survival (PFS) and overall survival (OS) rates compared to those with EGFR wild-type (n = 62, 44.0%), with rates of 74.2% vs 69.2% (P = 0.029) and 86.1% vs 67.7% (P = 0.009), respectively. The optimal cutoff values of TMTV were 36.42 cm3 for PFS and 37.51 cm3 for OS. Patients with high TMTV exhibited significantly inferior 2-year PFS and OS, with rates of 22.4% and 38.1%, respectively, compared to those with low TMTV, who had rates of 85.8% and 95.0% (both P < 0.001). In both the EGFR mutant and wild-type groups, patients exhibiting high TMTV demonstrated significantly inferior 2-year PFS and OS compared to those with low TMTV. In multivariate analysis, EGFR mutation status (hazard ratio, HR, 0.41, 95% confidence interval, CI [0.18–0.94], P = 0.034) and TMTV (HR 8.08, 95% CI [2.34–28.0], P < 0.001) were independent prognostic factors of OS, whereas TMTV was also an independent prognosticator of PFS (HR 2.59, 95% CI [1.30–5.13], P = 0.007).

Conclusion

Our study demonstrates that the integration of TMTV on baseline 18F-FDG PET/CT with EGFR mutation status improves the accuracy of prognostic evaluation for patients with LUAD.
Analysis of Fall Incidence Rate and Risk Factors at a Tertiary Care Hospital Setting for Inpatient Neurological Care using the Morse Fall Scale: A Prospective Study
Authors: Roy Riya , Chippala Purusotham
Published: January 2024

Introduction: Falls are the most common adverse events related to a patient safety in healthcare institutions. Falls during hospitalisation, particularly in inpatient rehabilitation facilities, are a common phenomenon among hospitalised individuals. The rationale of the present study is to reduce the incidence of falls by early identification of fall risk using an outcome measure. Aim: The aim of this study is to identify the fall incidence rate and associated factors responsible for falls in inpatients with neurological diseases using the Morse Fall Scale (MFS). Materials and Methods: This prospective study included 128 patients hospitalised in the Medicine and Neurosurgery Units of Justice KS Hegde Charitable Hospital in Mangaluru, Karnataka, Southern India. The study was conducted from March 2022 to March 2023. Factors were analysed through direct patient interviews, and fall risk scores were identified using the MFS during admission and discharge. Categorical variables were presented as frequency and percentage, while descriptive variables were presented as Mean±Standard Deviation. The pre-post comparison of the outcome measure was conducted using the Z-test. Results: The fall incidence rate in neurological inpatients was found to be 15 (11.7%), and the majority of the population belonged to moderate to high-risk of falls. During the hospitalisation period, 99 (77.3%) individuals had a fear of falling, while 29 (22.7%) did not have any fear of falling. Among the study population, 113 (88.3%) had no falls during their hospitalisation, while 15 (11.7%) experienced falls. The majority of subjects had a moderate risk of falls: 63 (49.2%) upon admission and 68 (53.1%) at discharge. There was a significant difference in the MFS scores between admission and discharge (p-value=0.024). Conclusion: The present study concludes that the MFS enables the identification of individuals at risk of falling. The variables related to these findings were the use of continuous medications, balance issues, fear of falling, followed by other factors such as age, length of hospital stay, previous hospitalisation, and sensory disorders.
A Case of Adenomatoid Odontogenic Tumour in a 14-year-old Female
Authors: Chakraborty Kaushik , Sardar Joyeeta
Published: January 2024

Adenomatoid Odontogenic Tumour (AOT) is a rare odontogenic neoplasm that primarily affects adolescents and young adults. The present case report discusses the presentation, diagnosis, and successful surgical management of AOT in a 14-year-old patient with a six-month history of upper left jaw swelling. Radiological investigations confirmed the lesion’s characteristics, leading to a provisional diagnosis of AOT. Subsequently, surgical enucleation and histopathological examination {Haematoxylin and Eosin (H&E)} confirmed the diagnosis. The patient showed no recurrence during follow-up at three weeks and six months postsurgery, with excellent functional and aesthetic outcomes. Postoperative follow-up is essential for optimal patient care and long-term outcomes. The present case report contributes to the existing literature on AOT, providing real-world clinical insights and data, which aids in a better understanding and management of this rare condition.
Специфика алмазов перидотитового и эклогитового парагенезиса: петрологические приложения, "Природа"
Authors: Специус З.В. , Богуш И.Н.
Published: January 2024

Изучены морфология, внутреннее строение, дефектно-примесный состав и состав минеральных включений в 50 пластинах алмазов из кимберлитов в шести промышленных месторождениях Якутии. Во всех объектах преобладают кристаллы с макровключениями ультраосновного парагенезиса. Отмечена дискретность алмазообразования и расположение некоторых макровключений на стыке разновозрастных зон. Кристаллы эклогитового парагенезиса (Е-типа), по сравнению с алмазами перидотитового парагенезиса (Р-типа), характеризуются большим суммарным содержанием азота и водорода, повышенным процентом зональных кристаллов. Показана высокая продуктивность ранних генераций алмазов перидотитового парагенезиса для Далдыно-Алакитского района, в то время как в Мало-Ботуобинском районе значительная часть алмазного вещества образовалась на поздних этапах эволюции литосферы в процессах метасоматоза. Приведены данные по изучению алмазосодержащих ксенолитов, преимущественно эклогитов, из трубок Удачной и Нюрбинской, а также сведения по особенностям внутреннего строения и вариациям изотопного состава углерода в алмазах из этих уникальных мантийных пород.
Лауреаты Нобелевской премии по физиологии или медицине 2023 года — Каталин Карико и Дрю Вайсман, "Природа"
Authors: Антропов Д.Н. , Прохорова Д.В. , Степанов Г.А.
Published: January 2024

Нобелевскую премию по физиологии или медицине в 2023 г. получили американские исследователи Каталин Карико и Дрю Вайсман «за открытия, касающиеся модификаций нуклеотидов, которые легли в основу разработки эффективных мРНК-вакцин против COVID-19». Эти исследователи десятилетиями искали стратегию создания вакцин и лекарств на основе мРНК. В 2005 г. они описали способ модификации РНК, благодаря которому создание мРНК-вакцин и мРНК-препаратов стало возможно. Результатом их совместных усилий стала технология, которая позволила использовать мРНК в качестве инструмента доставки генетической информации в клетки и в организм. Этот прорыв стал основой для создания вакцин на основе мРНК, которые показали высокую эффективность в борьбе с инфекционными заболеваниями и открыли перспективы разработки индивидуальных противораковых мРНК-вакцин. Работы Каталин Карико и Дрю Вайсман легли в основу самых массовых прививок против COVID-19 от «Pfi zer/BioNTech» и «Moderna». Хотя последняя пандемия и принесла нам целый букет действенных вакцин, например, «Спутник V», но именно мРНК-вакцины по праву считаются самыми инновационными и технологичными.
Effects of Different Vesicular - arbuscular Mycorrhizal (VAM) Fungi on the Seedling Growth of Tecomella undulata
Authors: Jangra Monika , Dalal Virender , Ahlawat Karan Singh , Chug Rakesh Kumar , Khaiper Mamta , Singh Vikram , Gulab  , Sumit
Published: January 2024

Tecomella undulata (Sm.) Seem. (family Bignoniaceae) is a tree found in desert parts of India, and Arabia. The cultivation of high-quality seedlings is vital for establishing a successful plantation and the contribution of arbuscular mycorrhizal fungi (AMF) in the soil plays a vital role in the nursery phase. A study conducted during the periods of 2021-22 and 2022-23 scrutinised the effect of four distinct species of Glomus spp. (G. mosseae, G. intraradices, G. fasciculatum and Glomus hoi) on Tecomella undulata seedlings in AMF-inoculated soil. The inoculation involved applying of 400-500 sporocarps/kg of soil during sowing and the evaluation encompassed growth and survival parameters. Results revealed that among the 4 Glomus species, soil inoculated with Glomus fasiculatum at 180 days after sowing, significantly increased the root colonization percentage with (50.69 and 46.71 %) in year (2021-22) and (2022-23) compared to the uninoculated control. Additionally, seedlings exhibited significantly higher no. of spores per 100g of soil, when treated with (Glomus fasiculatum) inoculated soil, which was statistically at par with soil inoculated with (Glomus intraradices) at (103.67 and 98.65). During both the experimental year, in terms of germination percentage, root length and root: shoot ratio were found non- significantly with (44.45 %), root length at 360 DAS, (26.67 and 25.74) respectively, root shoot ratio at 360 days after sowing. While, plant survival percentage (30.63 and 25.41%) at 90 DAS. Whereas, at 360 DAS, collar diameter (6.14 and 10.07 mm), shoot length (33.36 and 32.19 cm), plant biomass (8.31 and 8.05 g), leaf area (196.29 and 185.46 cm 2) was observed significantly higher in treatment T3 (Glomus fasiculatum) which was statistically at par with treatment T1 (G. intraradices). It is concluded from study that Glomus fasiculatum were found best for growth and survival of seedlings followed by Glomus intraradices as compare to control.
Successfully Completed Laparoscopic Splenectomy for Young Woman With Immune Thrombocytopenic Purpura During Pregnancy in Reduced Port Surgery: A Case Study
Authors: Baba Shigeaki , Sasaki Akira , Otsuka Koki , Umemura Akira , Takahara Takeshi , Akiyama Yuji , Iwaya Takeshi , Nitta Hiroyuki , Koeda Keisuke , Kimura Yusuke
Published: January 2024

Background

Immune thrombocytopenic purpura (ITP) during pregnancy is a rare condition; however, it can lead to hemorrhagic complications due to gestational thrombocytopenia during delivery. A splenectomy is the treatment that will result in the highest complete remission rate for ITP and is sometimes required when thrombocytopenia is severe and fails to respond to medical treatment. Herein, we present a case of a patient who underwent a reduced port laparoscopic splenectomy (RPLS) for ITP during pregnancy.

Case presentation

A 33-year-old female patient, who had past history of miscarriage at the 12th week of gestation and a stillbirth at the 36th week of gestation, was diagnosed with ITP at the 12th week of gestation. The patient received medical treatment, but the platelet count did not increase enough for spontaneous delivery. Therefore, a 3-port RPLS was scheduled at the 20th week of gestation following treatment with high-dose immunoglobulin therapy for 5 days.

The patient was placed in the right semilateral position. The pneumoperitoneal pressure was set at 8 mmHg, which is lower than that used in a typical operation. The overall procedures were similar to those of a 4-port technique.

Results

There was no change in the fetal heart rate during or after the operation. The platelet counts increased and were maintained after the RPLS, and the course of the pregnancy was successful. The patient was able to deliver a healthy infant via vaginal delivery at the 37th week of gestation.

Conclusion

In our experience, RPLS procedures offer high cosmetic satisfaction and are feasible and safe during the second trimester in pregnant women with ITP that does not respond well to medical treatments.
Weathering of granitic rocks by chlorides: effect of the nature of the solution on weathering morphology
Authors: Rivas T. , Prieto B. , Silva B. , Birginie J. M.
Published: April 2003

Five granites from NW Spain were subjected to two salt‐spray weathering tests under controlled atmospheric conditions. Granite samples were exposed to a sodium chloride solution in the first test and to a complex solution (sea water) in the second. Subsequent examination of the rocks by light and petrographic microscopy clearly demonstrated the development of different weathering morphologies in each test. The distribution of dissolved ions in samples taken at different depths from the weathered surfaces at the end of the experiments, and the changes in weight of the samples during the tests, also differed. In our opinion, these results were determined by the nature of the solution used; although sodium chloride is the predominant salt in sea water, the presence of other ions modifies its solubility, thereby varying the dynamics of mobility and precipitation and thus the weathering morphology that develops. Copyright © 2003 John Wiley & Sons, Ltd.
Biologically Active Polymers, 6
Authors: Kenawy El‐Refaie , Mahmoud Yehia A.‐G.
Published: April 2003

Various copolymers were prepared by the copolymerization of 2‐chloroethyl vinyl ether (CEVE) with methyl methacrylate (MMA), hydroxyethyl methacrylate (HEMA) and vinylbenzyl chloride (VBC). The copolymers were further modified by quaternization with triethylamine, triphenylphosphine, and tributylphosphine. The antimicrobial activities of the prepared, quaternized copolymers were evaluated against Candida albicans, Fusarium oxysporium, Aspergillus flavus, Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. The antimicrobial activity was explored by the cut plug method, viable cell counting (surviving ratio), transmission electron microscopy, and potassium leakage tests. The results indicated that the prepared polymers had a high antimicrobial activity, and control experiments on the main polymer without ammonium, phenyl, or butyl and/or phosphonium groups were carried out. The phosphonium containing polycationic biocides are more effective than the quaternary ammonium salt polymers. Examining the C. albicans and S. aureus polymer‐treated cells by electron microscopy indicated disruption for the cytoplasmic membrane and release of potassium ion as shown by the assay of potassium leakage.

Growth inhibition of different concentrations of polymer (Xb).

magnified image

Growth inhibition of different concentrations of polymer (Xb).
Comparison results for nonlinear elliptic equations with lower–order terms
Authors: Ferone Vincenzo , Messano Basilio
Published: April 2003

We consider a solution u of the homogeneous Dirichlet problem for a class of nonlinear elliptic equations in the form A(u) + g(x, u) = f, where the principal term is a Leray–Lions operator defined on $ W ^{1, p} _{0} (\Omega) $ and g(x, u) is a term having the same sign as u and satisfying suitable growth assumptions. We prove that the rearrangement of u can be estimated by the solution of a problem whose data are radially symmetric.
Macromonomer Chain Growth in the Radical Polymerization of MMA by Cobalt(II) Catalyzed Chain Transfer
Authors: Li Yunying , Wayland Bradford B.
Published: April 2003

Properties of the radical polymerization of methyl methacrylate in the presence of cobalt(II) tetraphenylporphyrin ((TPP)CoII•) as a chain transfer catalyst are reported. Reversible addition of (L)Co‐H to macromonomers gives living character to the oligomer olefins that grow to higher molecular weight without altering the primary polymer structural features. Incorporation of reversible termination of oligomer radicals in the mechanistic model for chain transfer catalysis by (L)CoII• complexes is an essential feature of the catalytic chain transfer process.

Average degree of polymerization as a function of monomer conversion for the (TPP)CoII• mediated CCT polymerization of MMA in C6D6 initiated by AIBN at different concentrations of (TPP)CoII•.

magnified image

Average degree of polymerization as a function of monomer conversion for the (TPP)CoII• mediated CCT polymerization of MMA in C6D6 initiated by AIBN at different concentrations of (TPP)CoII•.
Steric‐Factor‐Directed Alternating Supramolecular Copolymer Composed of Hydrogen‐Bonded Cyclohexanetricarboxamide Units
Authors: Takasawa Ryoichi , Murota Kazutoshi , Yoshikawa Isao , Araki Koji
Published: April 2003

Hydrogen‐bonded supramolecular copolymers were easily prepared by mixing cyclohexanetricarboxamides with three (1) and six (2) alkylsilyl groups, and supramolecular fibers were fabricated. When the composition of 1 and 2 was at or close to equimolarity, the supramolecular copolymer chain was found to have an alternating sequence. This was attributed to the fact that the steric factor of the alkylsilyl side chains effectively controls the unit sequence of the supramolecular polymer chain.

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Vibration analysis and optimization of a primary circuit of the nuclear power plant
Authors: Dupal J.
Published: April 2003

The mathematical model of the primary circuit of a nuclear power plant VVER 420/213 has been developed. The aim of modelling is a vibration analysis and parameter optimization leading to the decrease of velocity and stress amplitudes of the circuit components. For an assemblage of the mathematical model of the whole primary circuit the modal synthesis method with significant DOF reduction is used.
Computation of Controllability and Observability Matrices – Duality and Automatic Differentiation
Authors: Röbenack K.
Published: April 2003

During the last decades, many new methods for controller and observer design for nonlinear state‐space systems have been developed. Several of these design methods require Lie derivaties and Lie brackets. These derivatives are also needed to compute controllability and observability matrices of nonlinear systems. Up to now, these derivatives have been computed symbolically. An alternative approach based on automatic differentiation is presented.
Modellierung eines elastischen Roboterarmes
Authors: Krajcin Idriz
Published: April 2003

In diesem Beitrag wird eine Modellierung für einen hydraulisch angetriebenen Roboterarm vorgestellt. Die Modellierung beinhaltet sowohl die nichtlineare Eigendynamik eines Differenzialzylinders als auch die elastische Verformung des Roboterarmes, die mit Hilfe der Methode der Finiten Elemente modelliert wird. Mit dem vorgestellten Modell können verschiedene Strategien zur Regelung in Simulationen erprobt und verglichen werden. Die erprobten Regelungsstrategien können dann an dem Laborversuchsträger HyRob, der aus einem hydraulischen Antrieb und einem Arm aus Federrundstahl besteht, untersucht werden.
Behandlung der Dynamik von Eisenbahnschotter mittels Molekulardynamischer Simulation
Authors: Kruse Holger , Popp Karl
Published: April 2003

Die Molekulardynamische Simulation stellt ein leistungsstarkes Werkzeug zur Behandlung von granularen Medien wie dem Eisenbahnschotter dar. Im Gegensatz zu einer Kontinuumsbeschreibung wird jeder einzelne Schotterstein vom Modell erfasst. Durch Wahl geeigneter Kontaktgesetze können sowohl kurzzeitdynamische Vorgänge als auch das Setzungsverhalten qualitativ gut abgebildet werden. Interessante Einsatzgebiete sind u. a. eine Optimierung des Schottergleises hinsichtlich der Schwellengeometrie, der Untergrundsteifigkeit oder der Schottersteinform, eine Verbesserung von Stopfverfahren sowie die Berechnung von Verschiebewiderständen.
Microscopic and macroscopic modelling of foams
Authors: Diebels Stefan , Steeb Holger , Ehlers Wolfgang
Published: April 2003

The macroscopic behaviour of foams is influenced by the size and structure of the pores. Therefore, a Cosserat theory is motivated by a micromechanical beam model. A homogenization strategy is applied to the micromechanical model leading to results that are comparable to the predictions of the macroscopic Cosserat model.
Formulierung anisotroper, elektro‐mechanisch gekoppelter Materialgleichungen im Rahmen der Invariantentheorie
Authors: Romanowski H. , Schröder J.
Published: April 2003

Dieser Beitrag behandelt die Konstruktion anisotroper, elektro‐mechanisch gekoppelter Konstitutivgleichungen für geometrisch lineare Probleme. Hierzu führen wir die elektrische Enthalpie ein, die eine Potentialfunktion für die Spannungen und die elektrische Verschiebung darstellt. Als Modellproblem betrachten wir die Elektrostriktion für den Fall der transversalen Isotropie im Rahmen einer koordinateninvarianten Darstellung.
Experimentelle Untersuchung und thermomechanische Modellierung des Materialverhaltens von Gedächtnislegierungen
Authors: Helm D. , Haupt P.
Published: April 2003

Auf der Basis ein‐ und zweiaxialer Experimente an NiTi Formgedächtnislegierungen [1] wird ein geometrisch lineares Materialmodell für Formgedächtnislegierungen vorgestellt. Das Materialmodell basiert auf einer Materialfunktion für die Freie Energie sowie Evolutionsgleichungen für Innere Variable. Die Energiefunktion beschreibt dabei Energiespeicherungsvorgänge aufgrund der Thermoelastizität, der Engergiedifferenz zwischen den beiden betrachteten Phasen sowie die Energiespeicherung infolge der Entwicklung von Inneren Spannungen. Das geschichtsabhängige Materialverhalten von Formgedächtnislegierungen wird dagegen mit Hilfe von Evolutionsgleichungen modelliert. Das System der Konstitutivgleichungen erfüllt den 2. Hauptsatz der Thermodynamik in Form der Clausius–Duhem Ungleichung.
A closed‐form analysis of material and geometry effects on stress singularities at unsymmetric bimaterial notches
Authors: Nachname Müller, A.; Hohe, J.; Becker, W.
Published: April 2003

An important issue in the mechanics of adhesive bonds is the knowledge of local mechanical fields. In the present study, an asymptotic analysis of the stress fields near an unsymmetric bimaterial notch with arbitrary opening angle is performed. Using the complex potential method, the order of the singularity of the stress fields at a notch tip can be determined in closed‐form analytical manner, so that the dependency of the occurring singularity exponents on geometry and material properties can be studied systematically.
Fractional calculus applied to radiation damping
Authors: Trinks C. , Ruge P.
Published: April 2003

Separate treatment of the low– and high–frequency part of the dynamic stiffness is essential when approximating the latter in the frequency–domain. In this paper, a doubly–asymptotic rational approximation of the low–frequency part is combined with an analytical interpretation of the asymptotic part leading to a system of fractional differential equations to represent the force–displacement relationship. Here, an analogy between fading memory of viscoelastic materials and radiation damping of unbounded domains is visible.
Experimentelle Untersuchung des mechanischen Verhaltens von astfreiem Fichtenholz in radialer und tangentialer Richtung des Stamms
Authors: Fleischmann M. , Helnwein P. , Eberhardsteiner J.
Published: April 2003

Basierend auf einer Kleinserie einaxialer Druckversuche an astfreiem Fichtenholz wird in diesem Aufsatz ein viskoelastisch‐plastisches Materialmodell für Druckbeanspruchung in radialer Richtung vorgestellt. Weiters wird das beobachtete Verhalten in tangentialer Richtung erläutert.
Non‐smooth forced oscillations of a delaminated sandwich beam
Authors: Müller I. , Schmieg H. , Vielsack P.
Published: April 2003

Forced oscillations of delaminated sandwich structures are dominated by impacts. During motion the gap between the two adjacent parts of the structure opens and closes periodically. Each contact gives rise to an impact, which leads to energy loss. A 4 DOF beam model with concentrated masses allows discussion of principle on the influence of internal dissipation due to the impacts on the non‐linear system's response and the evolution of impacts near resonance points. Experimental investigations confirm the numerical results.
Choked flows in open capillary channel
Authors: Rosendahl U. , Ohlhoff A. , Dreyer M. , Rath H.J.
Published: April 2003

A forced liquid flow through an open capillary channel with free liquid surfaces is investigated. Since the free surfaces can only withstand a certain difference between the liquid pressure and the ambient pressure the flow rate in the channel is limited. The maximum flow rate is achieved when the surfaces collapse. A theoretical approach is presented which shows that the limitation of flow rate occurs due to choking. This theory confirms the results of an experiment performed on board the sounding rocket TEXUS‐37 to measure the maximum stationary volume flux of a forced flow through an open capillary channel.
Re.ned Modeling of the pressure redistribution/scrambling under consistent consideration of scalar turbulence effects in turbulent combustion
Authors: Maltsev A. , Sadiki A. , Janicka J.
Published: April 2003

In practical turbulent flow problems of engineering importance the coupling between velocity and scalar turbulence along with the variable density plays a non negligible role. For computations using second moment closure approach, the pressure redistribution/scrambling is the most critical term to be modeled as well known. Almost all existing models consist in rescating models derived on a constant density basis in a density weighted form. With regard to turbulent premixed combustion in fact, the application of such models to a range of transient one‐dimensional and two‐dimensional premixed flames in the flamelet regime has been found to yield unsatisfactory results, see [1]. As pointed out by Sadiki [2], the use of the Favre method must be consistently considered as far as open thermodynamic systems are concerned. Furthermore, the need for maintaining certain invariance properties, physical and mathematical realizability conditions in formulating turbulence models is well accepted. Because turbulent processes are irreversible, these efforts demand a carefull consideration of thermodynamic concepts.

Based on the results in [1] and following [2], this work aims to derive a physically consistent formulation of the pressure redistribution/scrambling term under consideration of the variable density. Considering the case of premixed flames, the thermochemistry is included by means of a single reactive scalar ‐ the reaction progress variable.

The accuracy of the model extensions proposed is demonstrated by comparing the numerical results with experimental data in opposed jet premixed flame configuration.
Movement of drops on a solid surface due to a contact angle gradient
Authors: Zielke Paul Ch. , Shankar Subramanian R. , Szymczyk Janusz A. , McLaughlin John B.
Published: April 2003

Experimental results on the motion of liquid drops on horizontal surfaces resulting from a contact angle gradient are presented. Silicon surfaces were modified using dodecyltrichlorosilane to generate the gradient. Water drops with initial diameters of 0.31 ‐ 0.5 mm (15 ‐ 65 nl) were placed on the surface, their movement videotaped, and subsequently analyzed. To characterize the gradient surface the static contact angle was measured along the surface.
Schadenserkennung mit genetischen Algorithmen
Authors: Engelhardt M. , Stavroulakis G.E. , Antes H.
Published: April 2003

Das Erkennen und nachfolgend die Lokalisierung einer Schädigung eines Bauteils mittels gemessener charakteristischer Daten führt auf ein inverses Schädigungsidentifizierungsproblem, welches als Optimierungsaufgabe mittels statischer Untersuchungen formuliert und anschliessend numerisch gelöst wird. Als Anwendungsbeispiel wird eine quadratische Scheibe mit einer oder mehreren Schädigungen im elastostatischen Bereich betrachtet, wobei die Schädigungen als Risse bzw. Ellipsen modelliert werden. Die Erzeugung der Messdaten wird hier ausschliesslich numerisch durchgeführt. Als Optimierungsverfahren zur Identifizierung der Schädigung wird ein genetischer Algorithmus verwendet. Das mechanische Problem wird mit der Hilfe der Randelementmethode modelliert. Die numerische Untersuchung betrachtet den Einfluss verschiedener relevanter Parameter, unter anderem die Anzahl der Ellipsen, die Anzahl und die Genauigkeit der Messungen und die Parameter der genetischen Optimierung.
Duality Based A Posteriori Error Estimator for the Dirichlet Problem
Authors: Repin S. , Sauter S. , Smolianski A.
Published: April 2003

The present work is devoted to the a posteriori error estimation for 2nd order elliptic problems with Dirichlet boundary conditions. Using the duality technique we derive a reliable and efficient a posteriori error estimator that measures the error in the energy norm. All the derivations are done on continuous level, and the estimator can be used in assessing the error of any approximate solution which belongs to the Sobolev space H1, independently of the discretization method chosen. In particular, we make no use of the Galerkin orthogonality, which enables us to implement the estimator for measuring the error of the fictitious domain/penalty finite element method. The estimator is easily computable, and the only constant present in the estimator is the one from Friedrichs' inequality; the constant depends solely on the domain geometry, and the estimator is quite non‐sensitive to the error in the constant evaluation. Finally, we show how accurately the estimator captures the local error distribution, thus, creating a base for a justified adaptivity of an approximation.
Reproducible manufacturing of dye‐sensitized solar cells on a semi‐automated baseline
Authors: Späth M. , Sommeling P. M. , van Roosmalen J. A. M. , Smit H. J. P. , van der Burg N. P. G. , Mahieu D. R. , Bakker N. J. , Kroon J. M.
Published: April 2003

A fully operational baseline consisting of dedicated equipment to process nanocrystalline dye‐sensitized solar cell devices has been installed at ECN. This baseline focuses on the production of glass/glass devices with dimensions up to 10×10 cm2. Present power conversion efficiencies of 6% obtained for cell areas of 2ċ5 cm2 are successfully translated to 100 cm2 devices with an active area of 68 cm2 by application of identical cell components. The power conversion efficiency with respect to total area was 4%. Processing of a large number of devices in the baseline shows good results in terms of process reliability and yield. The overall yield for a series of 27 devices (10×10 cm2) was 96%, while 84% (22 of the remaining 26 devices) generated a cell efficiency within 7% deviation from the average value (4ċ3%). The reproducibility of the titanium dioxide (TiO2) colloid synthesis has been investigated. The deviation from the average efficiency (4ċ9%) of three batches of colloid was at most 3ċ2%. These results prove that complete device manufacturing of nc‐DSC by a baseline process, starting with colloid synthesis is reproducible for surfaces up to 10×10 cm2. Copyright © 2003 John Wiley & Sons, Ltd.
Pierre Favard and Daniel Sandoz
Authors: André Jean
Published: April 2003

During the fall last year the 6th International Congress on Spermatology was held in Siena. This Congress was subtitled: Comparative Spermatology, 20 years after.

Pierre Favard and Daniel Sandoz had in fact participated in the first meeting held in Siena 20 years ago, and had disappeared since, Pierre nearly 2 years before, Daniel only a few months before the onset of the Congress.

When we, at the Organizing Committee, were preparing the Congress, we had first asked Daniel Sandoz to evoke the memory of his friend and former boss, Pierre Favard. Of course he accepted this task with devotion, but alas, his illness inerrupted his life before he could do it.

As they were both close friends to me, I asked for the privilege of commemorating their personalities. As they had been so close to each other — in their scientific life as well as in their editorial action of this Journal — I chose to let them united in the same praising oration.

The text that follows has been pronounced in Siena, on August 30, 1990.
De novo formation of centrioles in parthenogenetically activated, diploidized rabbit embryos
Authors: Szöllosi Daniel , Ozil Jean‐Pierre
Published: April 2003

Summary— In rabbit oocytes activated parthenogenetically by repetitive electric pulses, centrioles develop de novo in blastocysts. Centrioles were not observed in earlier stages of development, not until the blastocoele is formed. Up to the morula stage (between 8–32 cells), a filamentous, electron‐dense material develops and aggregates with a small vesicle fraction within the well developed Golgi apparatus. A spherical to ovoid electron dense mass forms, which is comparable to the deuterosome or to the blepharoplast. The quantity of the electron dense material enlarges and it seems to give rise to the centriole “generating complex”. Centrioles arise in all three differentiated cell types of the blastocysts, the mural and polar trophoblasts and the embryonal cell mass at the same time. Some of the forming centrioles in parthenotes have a co‐linear arrangement, as in control blastocysts. It is not yet known whether the co‐linearly arranged centrioles represent a maturation phase, prior to the formation of the usual diplosome, with centrioles oriented perpendicularly to each other. Nor is it known whether the forming centrioles are functioning as the polar organizer of the mitotic spindle or if they can perform any other centriolar function.