bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Circadian Clock Modulates Core Steps in Long-Term Memory Formation inAplysia
Authors: Lyons Lisa C. , Collado Maria Sol , Khabour Omar , Green Charity L. , Eskin Arnold 
Published: August 2006

The circadian clock modulates the induction of long-term sensitization (LTS) inAplysiasuch that long-term memory formation is significantly suppressed when animals are trained at night. We investigated whether the circadian clock modulated core molecular processes necessary for memory formationin vivoby analyzing circadian regulation of basal and LTS-induced levels of phosphorylated mitogen-activated protein kinase (P-MAPK) andAplysiaCCAAT/enhancer binding protein (ApC/EBP). No basal circadian regulation occurred for P-MAPK or total MAPK in pleural ganglia. In contrast, the circadian clock regulated basal levels ofApC/EBP protein with peak levels at night, antiphase to the rhythm in LTS. Importantly, LTS training during the (subjective) day produced greater increases in P-MAPK andApC/EBP than training at night. Thus, circadian modulation of LTS occurs, at least in part, by suppressing changes in key proteins at night. Rescue of long-term memory formation at night required both facilitation of MAPK and transcription in conjunction with LTS training, confirming that the circadian clock at night actively suppresses MAPK activation and transcription involved in memory formation.The circadian clock appears to modulate LTS at multiple levels. 5-HT levels are increased more when animals receive LTS training during the (subjective) day compared with the night, suggesting circadian modulation of 5-HT release. Circadian modulation also occurred downstream of 5-HT release because animals treated with 5-HT to induce LTS exhibited significantly greater LTS when treated during the (subjective) day compared with the night. Together, our studies suggest that the circadian clock modulates LTS at multiple steps and locations during the formation of long-term memory.
About the reliability of the Maximum Entropy Method in reconstructing electron density: the case of MgO
Authors: Merli Marcello , Pavese Alessandro 
Published: August 2006

Abstract
The reliability of the Maximum Entropy Method (MEM) to reconstruct finite temperature electron density (ED) is here discussed, investigating the case of periclase (MgO). A theoretical electron density has been generated by quantum mechanic calculations and folded with a function simulating atomic thermal motion, in order to produce a reference errorless ED [ρ(r)REF]. The Fourier coefficients of ρ(r)REF have been calculated, and used as “observed” diffraction intensities to reconstruct via MEM the original ED. The electron density attained by MEM [ρ(r)MEM] and ρ(r)REF have been compared with each other (pixel-by-pixel and critical points) to assess the ability of MEM to retrieve EDs, on the basis of a set of observed structure factors. We have carried out our study varying the number of observed structure factors [i.e. sin (θ)/λ cut-off], the nature of the prior-density [uniform density and procrystal-like model] and the way in which the prior-density is treated during MEM maximization [fixed or free to change]. We observe that (i) it is recommendable to use the prior-density as a start point only, and allow it to change during maximization; (ii) the closer is the prior-density to ρ(r)REF, the easier one attains by MEM a correct ED; (iii) if the prior-density is varied and a sufficient large number of observed structure factors used, then MEM tends to yield converging EDs, regardless of the prior-density chosen as a start point.
Deformed model sets and distorted Penrose tilings
Authors: Sing Bernd , Welberry T. Richard 
Published: August 2006

Abstract
In this article, we show how the mathematical concept of a deformed model set can be used to gain insight into the diffraction pattern of quasicrystalline structures. We explain what a deformed model set is, what its characteristic features are and how it relates to certain disorder phenomena in solids. We then apply this concept to distorted Penrose tilings, i.e., Penrose tilings where we apply size-effect-like distortions. While the size effect in crystals only operates on the diffuse scattering, there is also an intensity transfer on the Bragg peaks in distorted Penrose tilings. The persistence of pure point diffraction in distorted Penrose tilings can be explained by interpreting such tilings as deformed model sets.
Structural variations in the solid solution series of sodalite-type |(Eu
x
Ca2–x
)4(OH)8|[(Al2+x
Si1–x
)4O24]-SOD with 0 ≤ x ≤ 1, determined by X-ray powder diffraction and 27Al MAS NMR spectroscopy
Authors: Peters Lars , Knorr Karsten , Fechtelkord Michael , Appel Peter , Depmeier Wulf 
Published: August 2006

Abstract
The mineral bicchulite, |Ca8(OH)8|[Al8Si4O24]-SOD, has sodalite-(SOD)-type structure. It is one of the few minerals contradicting Loewenstein’s rule, as it contains twice as much Al as Si at the topologically unique tetrahedrally coordinated position, with both species being randomly distributed. The solid solution series |(EuxCa2–x
)4(OH)8|[(Al2+x
Si1–x
)4O24]-SOD with 0 ≤ x ≤ 1 and Δx = 0.125, was synthesized in order to clarify, whether the continuous violation of Loewenstein's rule is possible in an aluminosilicate framework structure like SOD, or whether the reported examples of SOD-type compounds with an Al : Si-stoichiometry of 2 : 1 represent a preferred composition on the tetrahedrally coordinated site of the structure. Here, we report on the variation of the lattice parameter and of some structural parameters in the series, determined by X-ray powder diffraction and results of 27Al MAS NMR spectroscopy. We found Loewenstein's rule to be systematically and continuously violated in this series. The observed structural variations mainly reflect stronger electrostatic interactions between the cage cations and the sodalite framework with increasing (Al + Eu)-content. While the evaluation of the X-ray diffraction data indicate a global adaptation of the sodalite framework to the cage guest size, the significant line-broadening of the NMR spectra with increasing (Al + Eu)-content points towards local adaptations of the framework to the shape of the cage guests.
New isostructural ethylenediammonium diphosphates (NH3(CH2)2NH3)2[Me(HP2O7)2 · 2 H2O] [Me = Co, Ni]: X-ray crystal structure and vibrational spectroscopy
Authors: Capitelli Francesco , El Bali Brahim , Essehli Rachid , Lachkar Mohammed , Valentini Veronica , Mattei Giorgio , Taraba Jan , Zak Zdirak 
Published: August 2006

Abstract
New ethylenediammonium diphosphates (NH3(CH2)2NH3)2[Me(HP2O7)2 · 2 H2O] [Me = Co (1), Ni (2)] have been synthesized and investigated by single-crystal X-ray diffractometry. The two structures resulted to be isostructural within triclinic space group P-1. The unit-cell parameters are: a = 7.5211(6) Å, b = 7.5574(3) Å, c = 9.7689(7) Å, α = 103.6(1)°, β = 111.14(1)°, γ = 98.04(1)°, V = 486.9(1) Å3 (1) and a = 7.4631(15) Å, b = 7.5274(12) Å, c = 9.743(3) Å, α = 104.28(2)°, β = 110.75(2)°, γ = 97.50(2)°, V = 481.4(2) Å3 (2). The three-dimensional network is built up by discrete Me(HP2O7)2 · 2 H2O moieties, which, via strong O—H … O bonds, form layers parallel to ab plane. Ethylenediammonium groups are located between such layers, stabilizing the framework via N—H … O bonds. The hydrogendiphosphate group presents bent eclipsed conformation, while the Me ion lies on inversion centre. The structural data, as the bent POP configuration, have been confirmed by the Raman and infrared spectra of the title compounds. In particular, the non-coincidence between the infrared and Raman bands supports the centrosymmetric structure of the investigated crystals.
Experimental charge density of an L-phenylalanine formic acid complex with a short hydrogen bond determined at 25 K
Authors: Mebs Stefan , Messerschmidt Marc , Luger Peter 
Published: August 2006

Abstract
The experimental charge density and related atomic and bond topological properties of an L-phenylalanine formic acid complex were derived from a high resolution X-ray data set (sin θ/λ = 1.18 Å–1/d = 0.42 Å) measured at 25 K. The complex consists of a zwitterionic and a cationic phenylalanine molecule with formate as counterion. Special focus was directed on the density distribution in the region of a strong O—H ·· O hydrogen bond (O ·· O = 2.491(1) Å) which is formed between the two phenylalanine units. The obtained results are compared with the 15 previously derived experimental amino acid charge density data, with various theoretical calculations at experimental geometries and with the complete set of topological descriptors based on ab initio calculations of the neutral forms of all 20 amino acids published recently in the literature. A comparison of all available data in this biologically important class of compounds gives an impression about the significance of the quantitative results from experimental and theoretical charge density determinations.
Numerical Modeling of Nasal Obstruction and Endoscopic Surgical Intervention: Outcome to Airflow and Olfaction
Authors: Zhao Kai , Pribitkin Edmund A. , Cowart Beverly J. , Rosen David , Scherer Peter W. , Dalton Pamela 
Published: August 2006

Background Mechanical obstruction of odorant flow to the olfactory neuroepithelium may be a primary cause of olfactory loss in nasal-sinus disease patients. Surgical removal of nasal obstruction may facilitate the recovery of olfactory ability. Unfortunately, quantifying the functional impact of nasal obstruction and subsequent surgical outcomes using acoustic rhinometry, rhinomanometry, or CT scans is inadequate. Methods Using computational fluid dynamics (CFD) techniques, we can convert patient CT scans into anatomically accurate 3D numerical nasal models that can be used to predict nasal airflow and odorant delivery rates. These models also can be rapidly modified to reflect anatomic changes, e.g., surgical removal of polyps. Results CFD modeling of one patient's nose pre- and postsurgery showed significant improvement in postsurgical ortho- and retronasal airflow and odorant delivery rate to olfactory neuroepithelium (<1000 times), which correlated well with olfactory recovery. Conclusion This study has introduced a novel technique (CFD) to calculate nasal airflow dynamics and its effects on olfaction, nasal obstruction, and sinus disease. In the future, such techniques may provide a quantitative evaluation of surgical outcome and an important preoperative guide to optimize nasal airflow and odorant delivery.
Modified Endoscopic Medial Maxillectomy for Chronic Maxillary Sinusitis
Authors: Woodworth Bradford A. , Parker Ryan O. , Schlosser Rodney J. 
Published: August 2006

Background Recently, modified endoscopic medial maxillectomy (MEMM) has been described as an alternative technique to open maxillectomy for benign sinonasal neoplasms. However, few reports discuss the efficacy of MEMM for treatment of inflammatory disease of the maxillary sinus. We evaluate the efficacy of MEMM in treating chronic maxillary sinusitis. Methods A retrospective review of patients who underwent MEMM for refractory inflammatory disease between December 2002 and September 2004 was performed. All patients were treated with MEMM alone or as part of an endoscopic sinus surgery procedure. Standard demographic data, operative technique, and postoperative follow-up times were collected. Results Nineteen patients (average age, 57 years) underwent 24 EMMs for chronic maxillary sinusitis refractory to middle meatal antrostomy. All patients failed prior sinus surgery, including 14 Caldwell-Luc procedures. Average follow-up was 19.5 months (range, 10–27 months). One patient has persistent hyperplastic sinusitis that currently requires monthly follow-up and medical treatment. Our only complication was one nasolacrimal duct injury. Conclusion MEMM is both a safe and an effective treatment for chronic maxillary sinusitis refractory to standard medical and endoscopic surgical management.
Increased Expression of Inducible Nitric Oxide Synthase in Nasal Mucosae of Guinea Pigs with Induced Allergic Rhinitis
Authors: Chiba Yoshihiko , Matsuo Kensuke , Sakai Hiroyasu , Abe Kazuho , Misawa Miwa 
Published: August 2006

Background Nitric oxide (NO) is produced by the action of NO synthase (NOS) isoforms and is considered an important mediator of inflammatory response including airways. In this study, the changes in the expression levels of NOS isoforms in nasal mucosae were determined in a guinea pig model of allergic rhinitis. Methods An allergic rhinitis model was prepared in guinea pigs by repeated challenge with aerosolized dinitrophenylated ovalbumin antigen. Twenty-four hours after the last antigen challenge, the expression levels of NOS isoforms in nasal mucosae were determined by immunoblottings. Changes in the isometrical tension of isolated mucosal tissues of nasal septa induced by histamine were measured also. Results Although the expression levels of endothelial NOS (eNOS) and neuronal NOS (nNOS) in nasal mucosae were not affected by the repeated antigen exposure, the inducible NOS (iNOS) level was markedly and significantly increased in the challenged animals. In isolated nasal mucosal tissues, histamine induced a concentration-dependent relaxation, which was sensitive to an H1-receptor antagonist, mepyramine, and an NOS inhibitor, l-NMMA. No significant change in the histamine responsiveness was observed between the sensitized control and repeatedly antigen-challenged groups. Conclusion The expression of three isoforms of NOS, including eNOS, nNOS, and iNOS, was presented in guinea pig nasal mucosa. A marked increase in iNOS expression in the repeatedly antigen-challenged animals suggests an important role of iNOS in the pathogenesis of allergic rhinitis. However, the pathophysiological role(s) of NO generated by iNOS in nasal allergy is still unclear.
Systemic Absorption of Gentamicin Nasal Irrigations
Authors: Whatley W. Stites , Chandra Rakesh K. , MacDonald C. Bruce 
Published: August 2006

Objective To determine if gentamicin nasal irrigation is systemically absorbed, and to identify any ototoxic side effects related to its use. Design Retrospective review of 12 patients treated with gentamicin nasal irrigations (30 cc of 80 mg/L solution used bilaterally twice daily). Methods Serum gentamicin levels were assayed after the course treatment. Pure tone audiometry (250–8000 Hz) and distortion product otoacoustic emissions (DP-OAEs) at 7280, 5133, 3640 and 2560 Hz were obtained before and after therapy. Results Twelve patients (age 4 to 74, mean 43) with chronic rhinosinusitis were treated for 3–15 weeks (mean 7 weeks). All patients had undergone previous endoscopic sinus surgery. Ten patients had pretreatment cultures that grew organisms sensitive to gentamicin (Pseudomonas, Proteus, or methacillin resistant Staphylococcus aureus), and three patients had cystic fibrosis. Ten of 12 patients (83%) had detectable posttreatment levels of gentamicin, with a mean serum level of 0.42 mcg/mL (range 0.3 to 0.7 mcg/mL). Four of 12 patients (33%) had serum gentamicin levels within the normal range for gentamicin trough (0.5 to 2 mcg/mL). Comparison of pre- and posttreatment audiologic data revealed no significant change in PTA or DP-OAE, except for the right ear at 8000 Hz on PTA (p = 0.035) where a mean of 7 dB loss was observed. No patient reported hearing loss or vertigo during treatment. Conclusion Gentamicin nasal irrigation may be systemically absorbed. Although the otologic consequences of this finding are questionable, patients receiving gentamicin nasal irrigations should be counseled regarding this hypothetical possibility.
Subjective Headache before and after Endoscopic Sinus Surgery
Authors: Moretz William H. , Kountakis Stilianos E. 
Published: August 2006

Background The aim of this study was to show the effect of endoscopic sinus surgery on subjective headache scores in patients diagnosed with chronic rhinosinusitis (CRS) with or without nasal polyps. Methods We performed a retrospective analysis of prospectively collected data from 201 patients over a 2-year period. Headache and Sino-Nasal Outcomes Test (SNOT-20) mean scores were compared preoperatively and 2 years postoperatively on patients diagnosed with CRS with or without nasal polyps. Results Two hundred one patients underwent surgical management of CRS with or without nasal polyps over a 3-year period. One hundred four patients were men and 97 were women, with a mean age of 49 (range, 18–80 years) years. Polyps were present in 78 patients with CRS. The mean subjective headache score based on a 0–10 visual analog scale improved from 4.7 preoperatively to 0.8 2 years postoperatively (p < 0.0001). The mean headache score of 123 patients without polyps was larger compared with 78 patients with polyps (5.1 versus 4.1, respectively; p < 0.05). As previously reported, the mean overall preoperative and postoperative SNOT-20 scores were 28.7 and 6.7, respectively (p < 0.0001). Conclusion Headache is a common symptom with CRS, present in 73.6% of our patients undergoing functional endoscopic sinus surgery for CRS with or without nasal polyps. An overall decrease in mean headache scores was noted at 2-year follow-up.
Characterization of Oxidative Pathways in Chronic Rhinosinusitis and Sinonasal Polyposis
Authors: Citardi Martin J. , Song Wei , Batra Pete S. , Lanza Donald C. , Hazen Stanley L. 
Published: August 2006

Background Eosinophils are a characteristic inflammatory cell infiltrate in both chronic rhinosinusitis (CRS) and sinonasal polyposis (SNP). The posttranslational modifications, 3-bromo-tyrosine (Br-Tyr) and 3-chloro-tyrosine (Cl-Tyr), serve as specific molecular markers for production of brominating and chlorinating oxidants, respectively, by the eosinophil peroxidase and myeloperoxidase systems of leukocytes. The aim of this study was to identify mechanisms of oxidative protein modifications in sinonasal mucosa of CRS and SNP patients by measuring Br-Tyr, Cl-Tyr, and alternative molecular markers of distinct oxidative pathways. Methods Levels of Br-Tyr; Cl-Tyr; di-Tyrosine (di-Tyr), a specific oxidative cross-link; ortho-tyrosine (o-Tyr) and meta-tyrosine (m-Tyr), markers for protein modification by hydroxyl radical-like oxidants; and nitro-tyrosine (NO2-Tyr), a stable product of nitric oxide (NO)–derived oxidants, were measured in anterior ethmoid mucosa tissue from CRS and SNP patients, as well as in middle turbinate mucosa from normal volunteers, using tandem mass spectrometry. Results Tissue levels of Br-Tyr were significantly higher in the CRS group compared with the control group (797 μmol/mol versus 515 μmol/mol tyrosine, p < 0.015), but no differences were detected for Cl-Tyr, di-Tyr, m-Tyr, o-Tyr, and NO2-Tyr. Tissue levels of both Br-Tyr and di-Tyr were significantly higher in the SNP group compared with the control group (879 μmol/mol versus 515 μmol/mol, p < 0.005; 5090 μmol/mol versus 1700 μmol/mol, p < 0.024, respectively), but no differences were detected for Cl-Tyr, m-Tyr, o-Tyr, and NO2-Tyr. Conclusion Br-Tyr, a molecular footprint predominantly formed by eosinophil peroxidase–catalyzed tissue damage, may serve as an objective index of CRS and SNP disease activity.
Effectiveness of Intraoperative Mitomycin C in Maintaining the Patency of a Frontal Sinusotomy: A Preliminary Report of a Double-Blind Randomized Placebo-Controlled Trial
Authors: Chan Kwai-Onn , Gervais Mireille , Tsaparas Yotis , Genoway Krista A. , Manarey Casey , Javer Amin R. 
Published: August 2006

Background Postoperative scarring in the frontal recess is the most common cause of iatrogenic frontal sinusitis. Topical mitomycin-C (MMC) is an antifibroblastic agent that has been shown to reduce clinical scarring. This is a preliminary report of a double-blind, randomized, placebo-controlled trial using MMC to determine its effectiveness in reducing frontal recess stenosis after frontal sinusotomy. Methods All patients with chronic rhinosinusitis undergoing primary or revision bilateral image-guided endoscopic sinus surgery were enrolled. Patients requiring frontal sinus stents and those with allergic fungal sinusitis were excluded. After completion of the frontal sinusotomy, dimensions of the frontal recess were measured using curved Frazer suction diameters. A neuropattie soaked in 0.5 mg/mL of MMC was then placed into one frontal recess for 4 minutes in a randomized manner. A saline control was used for the other side. The primary surgeon was blinded to the medicated side intraoperatively and throughout the follow-up period. Measurements of the frontal recess were repeated at 1, 3, and 6 months. Results There was no difference in the degree of frontal recess stenosis between the MMC and control sides at 1, 3, and 6 months postoperatively for both primary and revision cases. Conclusion One-time intraoperative topical MMC is not effective in reducing postoperative frontal recess stenosis in both primary and revision cases.
Intranasal Deposition of Nebulized Saline: A Radionuclide Distribution Study
Authors: Hwang Peter H. , Woo Rachel J. , Fong Karen J. 
Published: August 2006

Background Despite the popularity of various nasal sprays and nebulizers, there are limited data regarding the anatomic distribution of particles generated by these devices. This pilot study sought to characterize distribution patterns of nebulized and sprayed saline particles in normal subjects and postsurgical sinus patients. Methods Fifteen subjects were studied in three trials: metered-dose nasal spray bottle versus vortex-propelled nebulizer in normal subjects, passive-diffusion nebulizer versus vortex nebulizer in normal subjects, and passive nebulizer versus vortex nebulizer in postsurgical sinus patients. Radiolabeled saline was administered, and nose, lungs, and stomach were imaged. Images were scored by four blinded reviewers for degree of penetration at nine anatomic subsites. Results Compared with spray bottle, the vortex nebulizer showed more focal intranasal distribution with reduced nasopharyngeal, pharyngeal, and gastric penetration in normal subjects. Three of five subjects showed probable frontal sinus penetration by vortex nebulizer, but no other sinus penetration was noted. No patients showed sinus penetration with the spray bottle. In a separate trial against the passive nebulizer, the vortex nebulizer again showed a greater tendency for sinus penetration in normal subjects, with three of five showing some degree of sphenoid penetration and one of five showing slight maxillary penetration. In contrast, no sinus penetration was observed with the passive nebulizer. In the postsurgical patient cohort, minimal sinus penetration was noted with either the vortex nebulizer or the passive nebulizer. Despite surgically patent sinuses, only one of five subjects showed any type of sinus penetration. Conclusion The nebulizer and nasal spray devices tested in general showed limited penetration of the sinuses in both normal and postoperative patients. The device showing greatest promise for sinus penetration in normal patients was the vortex nebulizer, with an overall penetration rate in normal patients of 30% in the frontal, 30% in the sphenoid, and 10% in the maxillary. Understanding delivery patterns of topical therapies may be important in evaluating the efficacy of various topical treatment modalities.