bluuebunny/crossref_metadata_2025 huggingface dataset:
An Arabidopsis Basic Helix-Loop-Helix Leucine Zipper Protein Modulates Metal Homeostasis and Auxin Conjugate Responsiveness
Authors: Rampey Rebekah A , Woodward Andrew W , Hobbs Brianne N , Tierney Megan P , Lahner Brett , Salt David E , Bartel Bonnie
Published: October 2006

The plant hormone auxin can be regulated by formation and hydrolysis of amide-linked indole-3-acetic acid (IAA) conjugates. Here, we report the characterization of the dominant Arabidopsis iaa–leucine resistant3 (ilr3-1) mutant, which has reduced sensitivity to IAA–Leu and IAA–Phe, while retaining wild-type responses to free IAA. The gene defective in ilr3-1 encodes a basic helix-loop-helix leucine zipper protein, bHLH105, and the ilr3-1 lesion results in a truncated product. Overexpressing ilr3-1 in wild-type plants recapitulates certain ilr3-1 mutant phenotypes. In contrast, the loss-of-function ilr3-2 allele has increased IAA–Leu sensitivity compared to wild type, indicating that the ilr3-1 allele confers a gain of function. Microarray and quantitative real-time PCR analyses revealed five downregulated genes in ilr3-1, including three encoding putative membrane proteins similar to the yeast iron and manganese transporter Ccc1p. Transcript changes are accompanied by reciprocally misregulated metal accumulation in ilr3-1 and ilr3-2 mutants. Further, ilr3-1 seedlings are less sensitive than wild type to manganese, and auxin conjugate response phenotypes are dependent on exogenous metal concentration in ilr3 mutants. These data suggest a model in which the ILR3/bHLH105 transcription factor regulates expression of metal transporter genes, perhaps indirectly modulating IAA-conjugate hydrolysis by controlling the availability of metals previously shown to influence IAA–amino acid hydrolase protein activity.
The Association Among Gene Expression Responses to Nine Abiotic Stress Treatments inArabidopsis thaliana
Authors: Swindell William R
Published: October 2006

The identification and analysis of genes exhibiting large expression responses to several different types of stress may provide insights into the functional basis of multiple stress tolerance in plant species. This study considered whole-genome transcriptional profiles from Arabidopsis thaliana root and shoot organs under nine abiotic stress conditions (cold, osmotic stress, salt, drought, genotoxic stress, ultraviolet light, oxidative stress, wounding, and high temperature) and at six different time points of stress exposure (0.5, 1, 3, 6, 12, and 24 hr). In roots, genomewide correlations between transcriptional responses to different stress treatments peaked following 1 hr of stress exposure, while in shoots, correlations tended to increase following 6 hr of stress exposure. The generality of stress responses at the transcriptional level was therefore time and organ dependent. A total of 67 genes were identified as exhibiting a statistically significant pattern of gene expression characterized by large transcriptional responses to all nine stress treatments. Most genes were identified from early to middle (1–6 hr) time points of stress exposure. Analysis of this gene set indicated that cell rescue/defense/virulence, energy, and metabolism functional classes were overrepresented, providing novel insight into the functional basis of multiple stress tolerance in Arabidopsis.
Structure–Function Analysis of Delta Trafficking, Receptor Binding and Signaling in Drosophila
Authors: Parks Annette L , Stout Jane R , Shepard Scott B , Klueg Kristin M , Dos Santos Ana A , Parody Todd R , Vaskova Martina , Muskavitch Marc A T
Published: October 2006

The transmembrane proteins Delta and Notch act as ligand and receptor in a conserved signaling pathway required for a variety of cell fate specification events in many organisms. Binding of Delta to Notch results in a proteolytic cascade that releases the Notch intracellular domain, allowing it to participate in transcriptional activation in the nucleus. Recent research has implicated the endocytic and ubiquitylation machinery as essential components of Delta–Notch signaling. Our analysis of chimeric and missense Delta variants has delineated a number of structural requirements for Delta trafficking, receptor binding, and signaling. We find that while the Delta N-terminal domain is necessary and sufficient for binding to Notch, the integrity of the epidermal-growth-factor-like repeat (ELR) 2 is also required for Notch binding. Screening of 117 Delta mutant lines for proteins that exhibit aberrant subcellular trafficking has led to the identification of 18 Delta alleles (DlTD alleles) that encode “trafficking-defective” Delta proteins. We find, unexpectedly, that many DlTD alleles contain missense mutations in ELRs within the Delta extracellular domain. Finally, we find that two DlTD alleles contain lysine missense mutations within the Delta intracellular domain (DeltaICD) that may identify residues important for DeltaICD mono-ubiquitylation and subsequent Delta endocytosis and signaling.
Molecular Diversity After a Range Expansion in Heterogeneous Environments
Authors: Wegmann Daniel , Currat Mathias , Excoffier Laurent
Published: October 2006

Recent range expansions have probably occurred in many species, as they often happen after speciation events, after ice ages, or after the introduction of invasive species. While it has been shown that range expansions lead to patterns of molecular diversity distinct from those of a pure demographic expansion, the fact that many species do live in heterogeneous environments has not been taken into account. We develop here a model of range expansion with a spatial heterogeneity of the environment, which is modeled as a gamma distribution of the carrying capacities of the demes. By allowing temporal variation of these carrying capacities, our model becomes a new metapopulation model linking ecological parameters to molecular diversity. We show by extensive simulations that environmental heterogeneity induces a loss of genetic diversity within demes and increases the degree of population differentiation. We find that metapopulations with low average densities are much more affected by environmental heterogeneity than metapopulations with high average densities, which are relatively insensitive to spatial and temporal variations of the environment. Spatial heterogeneity is shown to have a larger impact on genetic diversity than temporal heterogeneity. Overall, temporal heterogeneity and local extinctions are not found to leave any specific signature on molecular diversity that cannot be produced by spatial heterogeneity.
Double-Strand Break Repair in Bacteriophage T4: Recombination Effects of 3′–5′ Exonuclease Mutations
Authors: Shcherbakov Victor P , Kudryashova E A , Shcherbakova T S , Sizova S T , Plugina L A
Published: October 2006

The role of 3′–5′ exonucleases in double-strand break (DSB)-promoted recombination was studied in crosses of bacteriophage T4, in which DSBs were induced site specifically within the rIIB gene by SegC endonuclease in the DNA of only one of the parents. Frequency of rII+ recombinants was measured in two-factor crosses of the type i × ets1, where ets1 designates an insertion in the rIIB gene carrying the cleavage site for SegC and i's are rIIB or rIIA point mutations located at various distances (12–2040 bp) from the ets1 site. The frequency/distance relationship was obtained in crosses of the wild-type phage and dexA1 (deficiency in deoxyribonuclease A), D219A (deficiency in the proofreading exonuclease of DNA polymerase), and tsL42 (antimutator allele of DNA polymerase) mutants. In all the mutants, recombinant frequency in crosses with the i-markers located at 12 and 33 bp from ets1 was significantly enhanced, implying better preservation of 3′-terminal sequences at the ends of the broken DNA. The effects of dexA1 and D219A were additive, suggesting an independent action of the corresponding nucleases in the DSB repair pathway. The recombination enhancement in the dexA1 mutant was limited to short distances (<100 bp from ets1), whereas in the D219A mutant a significant enhancement was seen at all the tested distances. From the character of the frequency/distance relationship, it is inferred that the synthesis-dependent strand-annealing pathway may operate in the D219A mutant. The recombination-enhancing effect of the tsL42 mutation could be explained by the hypothesis that the antimutator 43Exo removes a shorter stretch of paired nucleotides than the wild-type enzyme does during hydrolysis of the unpaired terminus in the D-loop intermediate. The role of the proofreading exonuclease in the formation of a robust replicative fork is discussed.
Long-Term Culturing of Undifferentiated Embryonic Stem Cells in Conditioned Media and Three-Dimensional Fibrous Matrices Without Extracellular Matrix Coating
Authors: Ouyang Anli , Ng Robin , Yang Shang-Tian
Published: October 2006

ESCs have unlimited proliferation potential and capability to differentiate into all tissue types. They are ideal cell sources for tissue engineering and cell therapy, but their supplies are limited. Current in vitro ESC cultures are carried out in tissue flasks with the surface precoated with extracellular matrix (ECM) proteins. T-flask cultures also require frequent subculturing because their limited surface area cannot support long-term growth of ESCs. In this work, ECM coating and frequent subculturing required in two-dimensional (2D) cultures were circumvented by culturing murine ESCs in three-dimensional (3D) polyethylene terephthalate (PET) fibrous matrices. Also, media conditioned with STO fibroblast cells were used to replace leukemia inhibitory factor and to effectively maintain the pluripotency of murine ESCs in a long-term static culture. However, the lactic acid present in the conditioned medium could inhibit ESC growth and induce spontaneous differentiation when its concentration exceeded 1.5 g/l. In addition, the 3D static culture could be limited by oxygen, which was depleted in the long-term culture when cell density in the matrix was high. However, these problems can be alleviated in dynamic culture with improved oxygen transfer and continuous media perfusion. The matrix pore size also had profound effects on ESCs. The smaller-pore (30–60 μm) matrix gave a higher proliferation rate and Oct-4 and stage specific embryonic antigen-1 expressions. Overall, the 3D culturing method is superior to the 2D culture method and can provide an economical way to mass-produce undifferentiated ESCs in uncoated matrices and conditioned media.
Clonogenic Endothelial Progenitor Cells Are Sensitive to Oxidative Stress
Authors: Ingram David A. , Krier Theresa R. , Mead Laura E. , McGuire Colleen , Prater Daniel N. , Bhavsar Janak , Saadatzadeh M. Reza , Bijangi-Vishehsaraei Khadijeh , Li Fang , Yoder Mervin C. , Haneline Laura S.
Published: October 2006

Endothelial progenitor cells (EPCs) circulate in the peripheral blood and reside in blood vessel walls. A hierarchy of EPCs exists where progenitors can be discriminated based on their clonogenic potential. EPCs are exposed to oxidative stress during vascular injury as residents of blood vessel walls or as circulating cells homing to sites of neovascularization. Given the links between oxidative injury, endothelial cell dysfunction, and vascular disease, we tested whether EPCs were sensitive to oxidative stress using newly developed clonogenic assays. Strikingly, in contrast to previous reports, we demonstrate that the most proliferative EPCs (high proliferative potential-endothelial colony-forming cells and low proliferative potential-endothelial colony-forming cells) had decreased clonogenic capacity after oxidant treatment. In addition, EPCs exhibited increased apoptosis and diminished tube-forming ability in vitro and in vivo in response to oxidative stress, which was directly linked to activation of a redox-dependent stress-induced kinase pathway. Thus, this study provides novel insights into the effect of oxidative stress on EPCs. Furthermore, this report outlines a framework for understanding how oxidative injury leads to vascular disease and potentially limits the efficacy of transplantation of EPCs into ischemic tissues enriched for reactive oxygen species and oxidized metabolites.
Concise Review: Epigenetic Mechanisms Contribute to Pluripotency and Cell Lineage Determination of Embryonic Stem Cells
Authors: Gan Qiong , Yoshida Tadashi , McDonald Oliver G. , Owens Gary K.
Published: October 2006

Epigenetic mechanisms, such as histone modifications and DNA methylation, have been shown to play a key role in the regulation of gene transcription. Results of recent studies indicate that a novel “bivalent” chromatin structure marks key developmental genes in embryonic stem cells (ESCs), wherein a number of untranscribed lineage-control genes, such as Sox1, Nkx2-2, Msx1, Irx3, and Pax3, are epigenetically modified with a unique combination of activating and repressive histone modifications that prime them for potential activation (or repression) upon cell lineage induction and differentiation. However, results of these studies also showed that a subset of lineage-control genes, such as Myf5 and Mash1, were not marked by these histone modifications, suggesting that distinct epigenetic mechanisms might exist for lineage-control genes in ESCs. In this review article, we summarize evidence regarding possible mechanisms that control these unique histone modifications at lineage-control gene loci in ESCs and consider their possible contribution to ESC pluripotency. In addition, we propose a novel “histone modification pulsing” model wherein individual pluripotent stem cells within the inner cell mass of blastocysts undergo transient asynchronous histone modifications at these developmental gene loci, thereby conferring differential responsiveness to environmental cues and morphogenic gradients important for cell lineage determination. Finally, we consider how these rapid histone modification exchanges become progressively more stable as ESCs undergo differentiation and maturation into specialized cell lineages.
Identification ofCXCR4as a New Nitric Oxide-Regulated Gene in Human CD34+ Cells
Authors: Zhang Yanyan , Wittner Monika , Bouamar Hakim , Jarrier Peggy , Vainchenker William , Louache Fawzia
Published: October 2006

As an intracellular second messenger, nitric oxide (NO) is increasingly implicated in the control of transcriptional machinery and gene expression. Here, we show that cell surface expression of CXCR4 on CD34+ cells was increased in a dose- and time-dependent manner in response to NO donors. Augmented surface expression was correlated with an increase in CXCR4 mRNA level. A specific NO scavenger prevented the elevation in CXCR4 mRNA caused by NO donors, suggesting a direct signaling action mediated by NO on CXCR4 transcription. NO treatment had no significant effect on CXCR4 mRNA stability. However, induction of CXCR4 mRNA by NO was still observed in conditions in which initiation of translation was inhibited, suggesting that the NO effect must be mediated by a pre-existing protein. CXCR4 mRNA induction did not involve cGMP (guanosine 3′, 5′-cyclic monophosphate) generation but was most likely mediated via oxidation of intracellular protein thiols. Finally, CD34+ cells pretreated with NO donors exhibited an increased chemotactic response. This study demonstrates that the NO pathway can modulate CXCR4 expression in human CD34+ cells and suggests that NO may play a critical role in the trafficking of hematopoietic progenitors.
Update on Capecitabine in Colorectal Cancer
Authors: Schmoll Hans-Joachim , Arnold Dirk
Published: October 2006

Learning Objectives

After completing this course, the reader will be able to: Discuss the potential use of oral capecitabine versus i.v. 5-FU in the treatment of colorectal cancer.Explain the evolving role of capecitabine in combination with novel, targeted therapeutics.Describe the role of capecitabine in combination with radiation therapy.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Referral to Medical Oncology: A Crucial Step in the Treatment of Older Patients with Stage III Colon Cancer
Authors: Luo RuiLi , Giordano Sharon H. , Freeman Jean L. , Zhang Dong , Goodwin James S.
Published: October 2006

Learning Objectives

After completing this course, the reader will be able to: Identify the predictors of seeing a medical oncologist for older colon cancer patients.Discuss the association between seeing a medical oncologist and chemotherapy use in stage III colon cancer.Outline the clinical implications for colon cancer care.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Therapy for Metastatic Colorectal Cancer
Authors: Goldberg Richard M.
Published: October 2006

Learning Objectives

After completing this course, the reader will be able to: Compare toxicity profiles among combination chemotherapy programs for colorectal cancer.Identify median survival times for chemotherapy programs for colorectal cancer.Discuss the new Intergroup trial schema and the rationale behind the study.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
The Present and Future of Angiogenesis-Directed Treatments of Colorectal Cancer
Authors: O'Dwyer Peter J.
Published: October 2006

Learning Objectives

After completing this course, the reader will be able to: Discuss the current status of clinical trials targeting angiogenesis in colorectal cancer.Identify the potential different mechanisms whereby antiangiogenic agents may interact with cytotoxic chemotherapy.Define potential mechanisms for resistance and sensitivity to antiangiogenic agents in colorectal cancer.

Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
The crystallization of arsenate‐contaminated iron hydroxide solids at high pH
Authors: Paige C. R. , Snodgrass W. J. , Nicholson Ronald V. , Scharer J. M.
Published: October 2006

A potential alternative technology for wastewater treatment streams involves coprecipitation with colloidal iron hydroxide followed by aging at elevated temperatures and high pH to produce crystalline iron oxides. The resultant crystalline oxides, in addition to having reduced sludge volume, may chemically/physically incorporate metal ions and/or metalloid oxyanions. The increased stability of the crystalline solids may be advantageous in reducing the rate of release of the contaminants to groundwater. The rate of transformation of iron hydroxide model wastewater treatment solids contaminated with arsenate into crystalline products was measured at 60 and 70°C. The rate of transformation was found to be described by either a solid‐state reaction equation for powdered compacts or a zero‐order reaction controlled by desorption. X‐ray diffraction demonstrates that, after crystallization has occurred, no solid solutions involving iron oxides and arsenate are formed.
Constructed reed beds clean up storm overflows on small wastewater treatment works
Authors: Green M. B. , Martin J. R.
Published: October 2006

Severn Trent Water is required to treat stormwater overflows that occur at sewage treatment works before discharge to receiving water courses. Where the regulator sets numeric quality standards on stormwater discharges from works serving populations of <2 000, treatment is provided in constructed reed beds. By June 1994 the company had 55 sites with reed beds for stormwater treatment and expects to provide more as an asset renewal programme continues. The paper describes discharge consent issues that are emerging and details the operation of the reed bed systems. Results from three surveys carried out during storm events show the benefit of the systems in reducing discharges of BOD5, TSS, ammonia N, and TON. A tracer study was carried out on one survey and the results are fitted to a simple mathematical model.
Modeling dissolved air flotation
Authors: Liers Sven , Baeyens Jan , Mochtar Indranata
Published: October 2006

Previously the flotation process was mainly characterized on an empirical basis. A model for dissolved air flotation (DAF) is presented that quantitatively describes the correlations and parameters used in both the contact and separation zones. This model includes two parameters, the bubble‐floc attachment efficiency (αpb) and the air‐to‐solid volume ratio in the agglomerates(β). The sensitivity of the model for assumptions on physico‐chemical and operational parameters and on the two parameters αpb and β is thereafter investigated. Experimental flotation efficiencies in a coaxial DAF column under varying operational conditions were in excess of 90% at surface loadings of 15 m/h and in excess of 95% at 10 m/h. The flotation model, combining bubble‐filter and separation efficiencies, was thereafter used to predict the efficiencies, and the model parameters αpb and β were determined by a best fit‐approach between model and experiment. The model is not too sensitive to values of these parameters. The defined αpb and β values correspond with previous literature data although the concept of the coaxial DAF improves the efficiencies compared with traditional rectangular DAF‐columns. The model can be used to calculate the efficiency for various possible operating conditions using either parameter values selected within the range of this paper or parameter values determined by fitting a limited number of small‐scale experiments.
Pollutant removal by a stormwater dry detention pond
Authors: Stanley Donald W.
Published: October 2006

Construction of a demonstration urban stormwater detention pond in Greenville, N.C., in 1992 provided an opportunity to assess the effectiveness of the pond in removing total suspended solids (TSS), nitrogen, phosphorus, organic carbon, and selected metals. The normally dry detention pond can hold, for ≥72 hr, the first 1.3 cm of runoff from its 81‐ha watershed, which is 31% impervious and 93% residential. Excess runoff from large storms bypasses the pond, flowing over a spillway near the inlet, whereas water detained in the pond, flows out through a perforated riser. The study included eight storms encompassing wide ranges in rainfall amounts (1.2‐23.6 cm) and duration (7.8‐115 hr). One of the storms was unusually large, resulting in 70% of the runoff bypassing detention. Pollutant concentrations in the untreated runoff were comparable with those for other study sites with similar land uses. Median event mean concentrations (EMCs) were 98 mg/L for TSS, 1.0 mg/L for total nitrogen (TN), and 0.35 mg/L for total phosphorus (TP). Lead, zinc, and other metals concentrations were also within ranges found elsewhere. Pond treatment efficiencies (PTEs) were calculated by comparing pollutant loads leaving the pond through the perforated riser with loads entering the pond (minus spillway bypass). Median PTEs were 71% for TSS, ∼45% for particulate organic carbon (POC) and particulate nitrogen (PN), 33% for particulate phosphorus (PP), and 26‐55% for metals. Dissolved pollutant loads leaving the pond were about the same as the runoff loads, except for phosphate phosphorus (PO4‐P), which had an average PTE of ∼25%. Differences between PTEs and storm treatment efficiencies (STEs), which take into account pond bypassing that occurs in large storms, were roughly proportional to the volumes of runoff that bypassed detention. At current TSS retention rates, only 0.16% of the pond storage volume would be lost per year, but trash accumulation and woody vegetation growth in the pond may reduce the storage volume much more rapidly than sedimentation. It is difficult to predict how the pond's performance will be affected by these changes.
Polymer addition as a solution to Nocardia foaming problems
Authors: Shao Y. J. , Starr Mark , Kaporis Kosta , Kim Hi Sang , Jenkins David
Published: October 2006

In February 1994, The Terminal Island Treatment Plant experienced severe Nocardia foaming problems. Attempts to control foaming, such as lowering the MCRT and foam removal and wasting, met with limited success. In April 1994, a final clarifier cationic polymer injection system was used to combat poor settling activated sludge. After 3 days of polymer addition, foaming was eliminated. The effectiveness of the polymer as a Nocardia foam control agent was verified in subsequent foaming incidents by conducting the full‐scale plant tests presented in this paper. Mechanisms are suggested for the action of the polymer in eliminating Nocardia foam. These include interaction with the foam‐stabilizing surfactants present in the wastewater, and polymer flocculation of dispersed Nocardia filaments into the activated sludge floc.
Evaluation of tertiary filtration and disinfection systems for upgrading high‐purity oxygen‐activated sludge plant effluent
Authors: Kuo J. F. , Dodd K. M. , Chen C. L. , Horvath R. W.
Published: October 2006

The Joint Water Pollution Control Plant (JWPCP) of the Sanitation Districts of Los Angeles County provides advanced primary and partial secondary treatment for 15.3 m3/s (350 MGD) of wastewater. A 7‐mo pilot plant study evaluated several tertiary treatment alternatives for in‐plant water reuse. The influent to the tertiary treatment system was the high‐purity oxygen‐activated sludge plant effluent. Three filtration systems were evaluated: a deep‐bed anthracite filter, a shallow‐depth pulsed‐bed sand filter, and a continuous backwash deep‐bed sand filter. Chlorination and ultraviolet (UV) disinfection were also compared. All three filters were capable of consistently meeting the State of California's effluent turbidity limit. The differences in turbidity removal efficiencies were insignificant. Changes in hydraulic loading rate, up to 0.2 m3/m2 · min (5 gpm/ft2), had insignificant effects on the quality of all filter effluents when filtering normal secondary effluent. The effect of chemical filter‐aids on turbidity removal depended strongly on the characteristics of the filter influent and the filter design configuration. Breakthrough of alum might occur with an excessive dosage of alum. The estimated costs for filtering the secondary effluent by the three filters were similar. A high‐UV dose of 300 mW‐s/cm2 would be required to reduce the total coliform concentrations ≤2.2 MPN/100 mL, mainly because of the low UV transmittance (40–63%). The 2.2 MPN/100mL coliform standard could be met either by a chlorine residual of 5 mg/L with a contact time of 120 min or 10 mg/L for 60 min.
Epidemiological aspects of thermophilic Campylobacter in water‐related environments: A review
Authors: Koenraad P. M. F. J. , Rombouts F. M. , Notermans S. H. W.
Published: October 2006

Campylobacteriosis is one of the most frequently occurring acute gastroenteritis diseases in humans. Studies have revealed that the main risk factors in contracting campylobacteriosis are eating undercooked poultry meat, drinking raw milk, or drinking untreated water, and to a lesser degree, living in a household with a cat or dog. During the past 5 years many transmission routes of Campylobacter have been elucidated. However, knowledge on the significance of surface waters in causing Campylobacter infections remains scarce. Various reports have shown that the aquatic environment is regularly contaminated with Campylobacter. Risk analysis indicates that the contribution of contaminated recreational water to human infections may be higher than previously assumed. The contribution of viable but nonculturable Campylobacter cells in the contamination cycle has been found to be negligible.
Similarity measure bias in river benthic Aufwuchs community analysis
Authors: Cao Yong , Williams W. Peter , Bark Anthony W.
Published: October 2006

An extensive assessment was made of nine common similarity measures on the basis of their discriminative ability and bias in weighting of different types of variation in species abundance between samples, by using sets of river macroinvertebrate samples. Seven agglomerative hierarchical clustering methods were applied to these measures. Successful site discrimination is defined as grouping of all replicate samples from a particular site. Major differences existed in the discriminative ability between the similarity measures. The measures overweight some types of variation and underweight the others to varying extents, which is closely related to their discriminative ability. A new dissimilarity‐similarity measure was devised to respond to all types of variation with minimum bias. This measure yielded a higher percentage of correct site discrimination than the others tested. Use of an extra data set confirmed the superior performance of the new measure and also indicated that it could discriminate between sites of different water quality.
Nasal Levels of Nitric Oxide as an Outcome Variable in Allergic Upper Respiratory Tract Disease: Influence of Atopy and Hayfever on nNO
Authors: Moody Alison , Fergusson Wendy , Wells Athol , Bartley James , Kolbe John
Published: October 2006

Background

The role of nasal levels of nitric oxide (nNO) as noninvasive marker of inflammation and as an outcome variable in allergic upper respiratory tract disease has not been defined. Our aim is to determine in patients with perennial allergic rhinitis (i) whether nNO is elevated, (ii) whether increased nNO is correlated with upper respiratory tract symptoms (discrimination), and (iii) whether changes in symptom scores are associated with changes in nNO levels (responsiveness).

Methods

Subjects (n = 38) with perennial rhinitis were studied weekly for 3 weeks. At each visit they completed a validated symptom questionnaire and had expired NO and nNO measured.

Results

Nasal NO levels were higher in those allergic to house-dust mite and cat. Nasal NO levels in subjects with perennial rhinitis were not elevated compared with non-atopic asymptomatic subjects. The intra-week reproducibility of nNO measurements was poor. There was no relationship between the symptom scores and nasal NO levels (discrimination). When analysis was confined to nasal symptoms, a weak but negative correlation was identified. Changes in symptom scores from week to week were not correlated with changes in nNO levels (responsiveness).

Conclusions

Nasal NO levels were not elevated in subjects with perennial rhinitis, and nNO levels were neither discriminatory nor responsive. The measurement of nNO therefore appears not to be a useful marker of disease activity in subjects with allergic rhinitis.
Smoking-Induced Olfactory Dysfunction in Chronic Sinusitis and Assessment of Brief University of Pennsylvania Smell Identification Test and T&T Methods
Authors: Sugiyama Kazuko , Hasegawa Yasuhiro , Sugiyama Naruji , Suzuki Motohiko , Watanabe Nobuhiro , Murakami Shingo
Published: October 2006

Background

To evaluate the outcome of smell activity after endoscopic sinus surgery in chronic sinusitis, it is important to verify evidence of smoking-induced olfactory dysfunction.

Methods

In both the preoperative and the postoperative stages, the 5-odorant T&T olfactometer (T&T5) and the 40-item University of Pennsylvania Smell Identification Test (UPSIT40) were administered to 100 patients (84 men and 16 women; mean age, 49.5 years; range, 21–75 years) who underwent surgery for chronic sinusitis. Additionally, as more simplified measures, we adopted a 3-odorant T&T (T&T3) and a 12-item UPSIT (UPSIT12), and then compared findings with those of each original method.

Results

(1) Obvious correlations of scores were noticed both between T&T5 and T&T3 and between UPSIT40 and UPSIT12 (r = 0.964 and 0.893, respectively), (2) significant changes in postoperative scores were observed on all four measurements (p < 0.0001), (3) smoking-induced hyposmia was noticeable in older subjects but not in younger subjects, and (4) the correlations of postoperative scores and the age of smoker or the smoking dose was significant (UPSIT40, r = 0.825 or 0.642; UPSIT12, r = 0.666 or 0.428; T&T5, r = 0.447 or 0.476; T&T3, r = 0.457 or 0.500, respectively).

Conclusion

The abbreviated measures of T&T3 and UPSIT12 could be available enough to assess the effect of surgical intervention on olfaction, while the original UPSIT40 was considered to be the most sensitive among the four methods tested here for examining the impact of smoking on olfaction.
Comparison of Anatomic, Physiological, and Subjective Measures of the Nasal Airway
Authors: Lam Derek J. , James Kathryn T. , Weaver Edward M.
Published: October 2006

Background

Studies comparing different categories of nasal measures have reported inconsistent results. We sought to compare validated measures of the nasal airway: anatomic (acoustic rhinometry), physiological (nasal peak inspiratory flow), and subjective experience (Nasal Obstruction Symptom Evaluation Scale and a visual analog scale [VAS]).

Methods

This prospective cross-sectional study of 290 nonrhinologic patients included upright and supine rhinometry (minimum cross sectional area [MCA] and volume) and flow (mean and maximum) measurements, as well as subjective measures. Associations between measures were evaluated with Spearman correlations and multivariate linear regression, adjusting for age, sex, race, body mass index, and smoking history.

Results

Correlations between objective (rhinometry and flow) and subjective categories of nasal measures ranged from –-0.16 to 0.03 (mean correlation, -0.07 ± 0.05), with 0 significant correlations of 16 tested. Correlations between anatomic (rhinometry) and physiological (flow) categories ranged from 0.04 to 0.15 (mean correlation, 0.10 ± 0.03), with 0 significant correlations of 16 tested. In contrast, within each category (rhinometry, flow, and subjective), all correlations were significant (13 correlations, all p < 0.001) and ranged from 0.62 to 0.99. Of 16 adjusted associations between objective and subjective measures, 14 were not significant (p > 0.05); only upright and supine MCAs were significantly associated with the VAS (both, p < 0.05).

Conclusion

Validated anatomic, physiological, and subjective nasal measures may assess different aspects of the nasal airway and provide complementary information. Future studies should be directed at developing a composite measure including components from all three categories of nasal measurement.
Superantigens and Chronic Rhinosinusitis: Skewing of T-Cell Receptor Vβ-Distributions in Polyp-Derived CD4+ and CD8+ T Cells
Authors: Conley David B. , Tripathi Anju , Seiberling Kristin A. , Schleimer Robert P. , Suh Lydia A. , Harris Kathleen , Paniagua Mary C. , Grammer Leslie C. , Kern Robert C.
Published: October 2006

Background

Recent studies have suggested that Staphylococcus aureus secrete superantigenic toxins that play a role in the etiology of chronic rhinosinusitis with nasal polyposis (CRSwNP). Twenty S. aureus superantigens (SAg's) have been identified, each of which bind the Vβ-region of the T-cell receptor (TCR) outside the peptide-binding site. Approximately 50 distinct Vβ-domains exist in the human repertoire, and distinct SAg's will bind only particular domains generating a pattern of Vβ-enrichment in lymphocytes dependent on the binding characteristics of a given toxin. The aim of this study was to analyze the pattern of Vβ-expression in polyp-derived lymphocytes from CRSwNP patients.

Methods

Polyps were harvested from 20 patients with CRSwNP and 3 patients with antrochoanal polyps. Flow cytometry was used to analyze the Vβ-repertoire of polyp-derived CD4+ and CD8+ lymphocytes. Data were analyzed in light of the known skewing associated with SAg exposure in vivo and in vitro. Skewing was defined as a percentage of Vβ-expression >2 SD of that seen in normal blood.

Results

Seven of 20 subjects exhibited skewing in Vβ-domains with strong associations with S. aureus SAg's. The three antrochoanal polyps failed to show any significant Vβ-skewing.

Conclusion

This study establishes evidence of S. aureus SAg–T-cell interactions in polyp lymphocytes of 35% of CRSwNP patients. Although these results are consistent with intranasal exposure of polyp lymphocytes to SAg's, additional study is necessary to establish the role of these toxins in disease pathogenesis.
Frequency of Discordant Documentation of Patient Race and Ethnicity
Authors: Salhi Rama A. , Macy Michelle L. , Samuels-Kalow Margaret E. , Hogikyan Megan , Kocher Keith E.
Published: March 2024

This cohort study examines longitudinal changes in race and ethnicity assignment in US hospitals.
Microbleeds in Heterozygous HTRA1-Related Cerebral Small Vessel Disease
Authors: Guo Yu , Peng Qing , Ling Chen
Published: March 2024

This case report describes the evaluation of a 44-year-old man with a history of headache, dizziness, and imbalance and imaging that showed lacunar infarctions and bilateral white matter hyperintensities.
Standardising field‐based assessment of invasion degree: A case study in two habitats of Reunion Island
Authors: Fenouillas Pauline , Caubit Margot , Cazal Emilie , Ajaguin Soleyen Cédric , Strasberg Dominique , Rouget Mathieu
Published: March 2024

Biological invasions represent one of the major threats to biodiversity conservation, especially in island ecosystems. Field‐based assessments of the invasion degree are required for managing and monitoring invaded habitats but there is no unifying measure available in the literature.

Here, we developed a standardised method for quantifying invasion degree based on four metrics: alien and native species cover, alien species richness, the occurrence frequency of alien species and invasion level, and demonstrated its use in two contrasted habitats of Reunion Island. This rapid survey quantified relative abundance and diversity of alien plant species among three vegetation strata (herbaceous, shrub and tree) in a systematic sampling.

In lowland tropical forest, it took 40 person days to survey 150 ha (344 plots), and 52 person days in subalpine vegetation to survey 125 ha (304 plots). Our results showed that the herbaceous stratum was the most invaded in terms of invasion level; more than 45% in lowland tropical forest and almost 55% in subalpine vegetation. Based on cluster analysis and kriging, we mapped three different levels of invasion highlighting potential invasion fronts. We found that it was important to differentiate invasion degree per vegetation strata as mean alien cover was significantly different between strata at each site.

This method is suitable for the majority of protected areas where fine‐scale assessment is required to characterise the spatial pattern of plant invasions, monitor invasive species and identify invasion foci to control or populations of emerging species to eradicate.
Protocol parameter extraction and centralization framework for comprehensive and in‐depth CT protocol review and management
Authors: LaBella Andy , Zhang Da
Published: March 2024

CT protocol management is an arduous task that requires expertise from a variety of radiology professionals, including technologists, radiologists, radiology IT professionals, and medical physicists. Each CT vendor has unique, proprietary protocol file structures, some of which may vary by scanner model, making it difficult to develop a universal framework for distilling technical parameters to a human‐readable file format. An ideal solution for CT protocol management is to minimize the work required for parameter extraction by introducing a data format into the workflow that is universal to all CT scanners.

In this paper, we report a framework for CT protocol management that converts raw protocol files to an intermediary format before outputting them in a human‐readable format for a variety of practical clinical applications, including routine protocol review, protocol version tracking, and cross‐protocol comparisons.

The framework was developed in Python 3. Technical parameters of interest were determined via collaborative effort between medical physicists and lead technologists. Protocol files were extracted and analyzed from a variety of scanners across our hospital‐wide CT fleet, including various systems from Siemens and GE. Protocols were subcategorized based on relevant technical parameters into regular, dual‐energy, and cardiac CT protocols. Backend code for technical parameter extraction from raw protocol files to a JavaScript Object Notation (JSON) format was performed on a per‐system basis. Conversion from JSON to a readable output format (MS Excel) was performed identically for all scanners using the universal framework developed and presented in this work. Example results for Siemens and GE scanners are shown, including side‐by‐side comparisons for protocols with similar clinical indications.

In conclusion, our CT protocol management framework may be deployed on any CT system to improve clinical efficiency in protocol review and upkeep.
Unified finite‐time fault estimation and fault‐tolerant control for Takagi–Sugeno fuzzy singular systems
Authors: Keerthana N. , Sakthivel R. , Aravinth N. , Marshal Anthoni S.
Published: March 2024

With the aid of a proportional integral framework, the presented article focuses on the problems of finite‐time boundedness and fault estimation for Takagi–Sugeno fuzzy singular systems subject to time delays, faults and external disturbances. To commence, we conjure up a fuzzy‐dependent intermediate variable and from thereon, a proportional integral‐based fuzzy intermediate estimator is constructed. Moreover, the constructed estimator precisely facilitates for estimating the fault signals and system states in simultaneously. Besides this, the integral term in the proportional integral estimator offers greater design flexibility and higher resilience. Secondly, an intermediate estimator‐based fault‐tolerant control is devised by availing the information from the proportional integral‐based fuzzy intermediate estimator, which aids in effectively compensating the faults arising in the system. Subsequently, by setting up an appropriate Lyapunov–Krasovskii functional, the set of adequate requirements asserting the finite‐time boundedness with the endorsed mixed and passivity performance index is established in terms of linear matrix inequalities. After that, an explicit framework for the requisite gain matrices can be found forth basing on the formed linear matrix inequality criteria. Ultimately, simulation findings are supplied to evaluate the utility and applicability of the theoretical insights.
Practical finite‐time fuzzy control of uncertain nonstrict‐feedback systems with actuator saturation and output constraints
Authors: Haddad Mohammed , Boulkroune Abdesselem , Li Hongyi
Published: March 2024

This article investigates the devise issue of a practical finite‐time output‐tracking control for uncertain nonlinear nonstrict‐feedback systems subject simultaneously to time‐varying output constraints (TVOC), actuator saturation, and bounded unmatched disturbances. An adaptive fuzzy approximator‐based control system is devised using the dynamic surface control (DSC) concept. System output constraints are addressed by employing an appropriate barrier Lyapunov function. Adaptive fuzzy disturbance observers are constructed to practically deal with time‐varying unmatched but bounded disturbances. It is verified via Lyapunov stability analysis and simulation experiments that all closed‐loop signals remain bounded, the output tracking error practically converges in finite time to a tiny but adjustable neighborhood around the origin, and the system output stays within its required time‐varying bounds.
Enhanced Performance of Ultraviolet AlGaN/GaN Photo‐HEMTs by Optimized Channel Isolation Schemes
Authors: Mondal Ramit Kumar , Xiong Zhongshu , Ghimire Mohan Kumar , Lingaparthi Ravikiran , Nethaji Dharmarasu , Radhakrishnan K , Kim Munho
Published: March 2024

Solar blind ultraviolet (UV) photodetectors utilizing AlGaN/GaN high electron mobility transistor (HEMT) structure offer a very high responsivity, photo‐to‐dark current ratio (PDCR), and detectivity. However, the performance of conventional mesa‐isolated photo‐HEMT is limited due to current leakage paths through the side wall and AlGaN barrier. In this work, apart from conventional mesa‐type isolation, ion implantation and metal‐insulator‐semiconductor (MIS) schemes are adopted to isolate the channels of AlGaN/GaN photo‐HEMTs. A significant reduction in dark current is achieved for MIS photo‐HEMT of around four and three orders of magnitude as compared to those of conventional mesa‐ and ion‐implanted photo‐HEMTs, respectively. Moreover, the responsivity and PDCR of MIS photo‐HEMT are around three and four orders of magnitude higher than those of conventional mesa‐isolated photo‐HEMT. Subsequently, MIS photo‐HEMT on Si substrate has achieved a very high detectivity of 4.63 × 1016 Jones at the UV incidence wavelength of 360 nm. The results presented in this work establish the advantages of MIS photo‐HEMT over other types of photo‐HEMTs. In addition, compatibility with GaN device fabrication technology and significantly enhanced optoelectronic performance suggest AlGaN/GaN MIS photo‐HEMTs as a promising candidate for a variety of advanced UV sensing applications.
Hybrid Co‐Solvent‐Induced High‐Entropy Electrolyte: Regulating of Hydrated Zn2+ Solvation Structures for Excellent Reversibility and Wide Temperature Adaptability
Authors: Jia Hao , Jiang Xinwei , Wang Yidi , Lam Yintung , Shi Shuo , Liu Guoshuai
Published: March 2024

As a new generation of lithium‐ion battery alternative, aqueous zinc (Zn) ion batteries (ZIBs) garner tremendous interests for future energy storage application owing to their inherent incombustible, nontoxic, and low‐cost features. However, their practical utilization is hampered by the electrolyte freezing at subzero conditions. In this study, a novel high‐entropy (HE) electrolyte fabricated is presented with hybrid solvents to mitigate electrolyte freezing at low temperatures, restrain calendar corrosion, and boost Zn‐ion transfer kinetics. Specifically, the isovolumetric combined ethyl acetate, ethylene glycol, and dimethyl sulfoxide as solvent components not only induce a reconfiguration of hydrogen bonding, but also alter the solvation sheath of Zn ions within the HE electrolyte environment. This synergistic coupling of hybrid co‐solvents effectively harnesses the features of individual solvent additive and facilitates the remarkable advantages on cycling reversibility, especially in the low‐temperature conditions. Benefiting from the anti‐freezing and solvation structure regulation features, Zn symmetrical batteries equipped with HE electrolytes can work over 2500 h in low zinc salt concentration (1 m) at various temperatures. This work provides a facile modulation strategy to achieve the HE electrolyte, promoting the practical application and commercialization of advanced ZIBs with wide‐temperature adaptability.
Optimizing particle morphology: Atomic iron–nitrogen centers with graphitic‐N for highly efficient CO2 electroreduction
Authors: Li Yan , Zeng Libin , Zhao Zilin , Zhang Qinghua , Hou Yang
Published: March 2024

Transition metal‐coordinated nitrogen sites on carbon catalysts (M‐N‐C) hold potential for CO2 electroreduction (CO2ER), but optimal morphology and active sites are unclear. We introduce a novel approach, developing zeolitic imidazolate framework‐8 (ZIF‐8)‐derived carbon catalysts with Fe‐N and graphitic‐N sites (Fe2‐NC) via molecular confinement and thermal activation. Fine‐tuning ZIF‐8 size and activation temperature yielded 44.98% active N sites. The 300 nm Fe2‐NC catalyst displayed outstanding CO2‐to‐CO conversion, with a 170 mV overpotential and 94.3% Faradaic efficiency at −0.5 V, outperforming state‐of‐the‐art materials. Enhanced CO2ER kinetics and conductivity contributed to this superiority. Results highlight the correlation between maximum CO Faradaic efficiency and cumulative Fe‐N/graphitic‐N sites, dependent on size and activation. The 300 nm Fe2‐NC in a gas diffusion electrode‐loaded flow cell achieved a 15.3‐fold CO partial current density increase. In a Zn‐CO2 battery, the 300 nm Fe2‐NC demonstrated a peak power density of 0.618 mW cm−2, showcasing energy storage potential.