bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of horizontal gradients on GPS radio occultation observation operators. I: Ray tracing
Authors: Poli P. , Joiner J. 
Published: January 2005

AbstractGlobal Positioning System (GPS) radio occultation (RO) bending angle and refractivity data provide information about the vertical structure of temperature and humidity in the earth's atmosphere. Assuming spherical symmetry in a GPS RO observation operator creates errors when calculating GPS RO observables from a background. These errors find their source in the presence of horizontal gradients of temperature and humidity. Tangent point drift (TPD) causes occulting rays to scan the atmosphere in various occultation planes. Horizontal gradients along the ray (HGR) cause the bending of each ray to be different from calculations that assume spherical symmetry.Using simulations, we show that HGR‐induced r.m.s. errors are larger than TPD‐induced r.m.s. errors in the lower troposphere only. TPD‐induced errors are more important in the stratosphere. We account for TPD and HGR using a multi‐plane two‐dimensional (2D) ray‐tracing observation operator. We show that bending angle and refractivity can be calculated more accurately with this 2D operator than an operator that assumes spherical symmetry. We use 6335 CHAMP and SAC‐C occultations as a validation. These occultations were processed by the Jet Propulsion Laboratory using geometrical optics and canonical transform methods. Our results indicate that analyses and 6‐hour forecasts can provide sufficiently accurate horizontal gradient information to the 2D operator. We show that the effects due to HGR can be satisfactorily simulated using ray tracing in one plane only. The effects due to TPD can be accounted for by considering a slanted profile which follows the tangent point trajectory. These results have important implications for the development of fast observation operators for data assimilation in numerical weather prediction. Copyright © 2004 Royal Meteorological Society
Effects of horizontal gradients on GPS radio occultation observation operators. II: A Fast Atmospheric Refractivity Gradient Operator (FARGO)
Authors: Poli P. 
Published: January 2005

AbstractPrevious works have suggested that strong atmospheric horizontal gradients need to be accounted for in the simulation of Global Positioning System radio occultation (GPS RO) refraction measurements. The contribution of such horizontal gradients to GPS RO observables can be calculated from a background with a multi‐plane two‐dimensional (2D) ray tracer. In part I we showed that the effects of horizontal gradients can be separated into tangent point drift (TPD) and horizontal gradients along the ray (HGR). We present here a fast observation operator called FARGO. FARGO incorporates both TPD and HGR effects but presents computation times 48 times faster than 2D ray tracing for calculating bending angle and more than 250 times faster for refractivity. TPD effects are simulated using slanted profiles while the HGR correction is applied in one occultation plane only and limited to the vicinity of the tangent point.When compared to observation operators which assume spherical symmetry, FARGO allows for reductions in the r.m.s. of the differences between observed and calculated bending angles and refractivities which are similar to those obtained with 2D ray tracing. Such reductions of the observed minus calculated refractivity can reach 80% for an occultation which occurred perpendicular to a tropospheric refractivity ridge (axis of high values) along a warm sector containing high water vapour amounts. We found that in about 5% of the cases, accounting for horizontal gradients via FARGO reduces the differences from real data by more than a half. The method used by FARGO to account for horizontal gradients can be extended for simulating refraction measurements collected by other instruments. Copyright © 2004 Royal Meteorological Society
Resolution dependence of orographic torques
Authors: R. Brown A. 
Published: January 2005

AbstractAn evaluation of the performance of the subgrid orography parametrization scheme in the ECMWF Integrated Forecast System is made by examining the variation with resolution of the orographic torques (resolved and parametrized) in short‐range global forecasts. As the spectral resolution is increased from T95 to T511, the magnitudes of the resolved torques increase while those of the parametrized torques decrease. In general the changes in the total orographic torques are reasonably small, but an important exception is between 20°N and 50°N in winter. Here the total orographic torque decreases significantly with increasing resolution. Through examination of errors in the modelled angular momentum budgets, it is suggested that the problems lie primarily at the low resolution end, where the parametrized orographic torques seem to be excessive. Furthermore, recent work with the NCEP reanalysis data suggests that this result may not be unique to the ECMWF system. Copyright © 2004 Royal Meteorological Society
Chromium(III) Removal from Wastewaters by a Weakly Acidic Resin Containing Carboxylic Groups
Authors: Kocaoba S. , Akcin G. 
Published: January 2005

As a conservative technology, ion exchange allows the removal and recycling of metals from liquid effluents. A process was applied for the removal of chromium(III) from wastewaters by ion exchange. This process was based on a weakly acidic cation-exchange resin (Amberlite IRC 86) capable of removing chromium(III) from the effluent, followed by selective separation and recovery during a regeneration procedure. Because of the difficult regeneration behaviour of the metal form of the carboxylate resin, special emphasis was given to the regeneration step of the resin where most of the practical problems were found. Five different regeneration procedures were adopted: elution with 1 M NaOH; elution with 1 M H2SO4; elution with 1 M NaOH followed by 1 M H2SO4 or vice versa; elution with NaOH followed by 1 M H2SO4/Na2SO4 solution; and elution with alkaline H2O2/NaOH solutions followed by 1 M H2SO4. A non-conventional regenerant solution such as hydrogen peroxide in an alkaline medium seemed very promising. The anionic species formed (chromate) was eluted quantitatively from the cation-exchange resin and separated. The regeneration efficiency of chromium(III) was 89.5%. Influent chromium concentrations employed during the tanning process used in the leather industry were also considered. For this purpose, influent concentrations in the range 60–100 mg/l, service flow rates of 10 and 20 l/h and appropriate retention times were selected and experiments undertaken in a column system. The exhaustion step was carried out at 250 l/h with the recovery of chromium being 95.6%. The ion-exchange capacity of Amberlite IRC 86 was found to be 1.28 equiv/l. This study undertaken under laboratory conditions demonstrated that Amberlite IRC 86 resin was suitable for the removal of chromium(III) from wastewater.
Moisture Sorption Isotherms of Whey Powder Spray in the 10–40°C Temperature Range
Authors: Stencl J. 
Published: January 2005

The results of water sorption tests on whey powder spray carried out under laboratory conditions were presented together with mathematical analyses of the sorption isotherms. Moisture equilibrium data were investigated at air temperatures over the temperature range 10–40°C and water activity ranging from 0.3 to 0.99. The experimental procedure used was a gravimetric dynamic method with continuous registration of sample weight changes. A special laboratory drying device was developed for the purpose. The sorption capacity decreased as the temperature increased. Re-hydration of the dried material resulted in hysteresis but this phenomenon was limited. Four models of equilibrium moisture content/water activity (Chung-Pfost, Halsey, Henderson and Oswin) were evaluated for their ability to fit the data for the samples tested. The Henderson equation provided a good model for moisture adsorption and desorption by whey powder spray.
Investigation of the Structure of Polyethylene Glycol (PEG) Layers Adsorbed at the Alumina-Polymer Solution Interface
Authors: Chibowski St. , Paszkiewicz M. , Mazur-Opala E. 
Published: January 2005

The investigations presented were aimed at a description of the structure of the adsorbed layers of polyethylene glycol (PEG) on the surface of Al2O3. This was obtained from measurements of the adsorption heat of PEG macromolecules as well as of 1,2-dimethoxyethane (C4H10O2) and tetraethylene glycol dimethyl ether (C10H22O5), i.e. low-molecular weight compounds constituting the monomers forming the PEG chain. The results allowed the fraction of polymer segments bonding directly to the Al2O3 surface to be estimated. Other information obtained from calculations based on the Scheutjens–Fleer theory included the distribution of chain segment conformations as trains, loops and tails, together with a determination of some structural changes and the sizes of PEG macromolecules as they moved from the bulk solution to the solid phase surface. The thickness of the adsorbed macro-molecular polymer layers on the alumina surface was also determined. All these data enabled an approximate description to be made of the polymer chain structure at the Al2O3–polymer solution interface.
Over-the-Counter Medicine Use Prior to and During Hospitalization
Authors: Oborne C Alice , Luzac Michal L 
Published: January 2005

BACKGROUND: In the UK, medicines are being reclassified from prescription-only drugs to allow supply without prescription. This allows faster and easier access to medicines to treat minor ailments and allows patients to take greater responsibility for their health. However, over-the-counter (OTC) drugs may pose risks to patients; thus, it is important to understand patients' OTC medicine use. OBJECTIVE: To assess use of OTC drugs prior to and during hospital stay of inpatients of all ages and specialties. METHODS: Data were collected for 186 randomly selected patients. Patients were interviewed about OTC medicine use. Clinical notes and drug charts were examined for documentation of OTC medicine use. RESULTS: A total of 268 OTC medicines were used by 119 (64.0%) patients, and 117 (43.7%) were taken at least daily. Only 13 (4.9%) OTC drugs were recorded in the drug history taken at admission. Twenty-six (9.7%) OTC agents were still taken during hospitalization, but only 8 (31%) were recorded on drug charts. Patients bought 183 (68.3%) items from pharmacies, 28 (10.4%) in health food shops, and 57 (21.7%) elsewhere including supermarkets, homeopaths, or mail order. Patients had little knowledge of potential adverse effects or contraindications. CONCLUSIONS: Many patients use OTC medication prior to and during hospital stay, but documentation in hospital notes is poor. Healthcare professionals must pay closer attention to patients' use of OTC drugs.
Eptifibatide-Associated Acute, Profound Thrombocytopenia
Authors: Coons James C , Barcelona Robert A , Freedy Tucker , Hagerty Michael F 
Published: January 2005

OBJECTIVE: To describe 3 cases of eptifibatide-associated acute, profound thrombocytopenia. CASE SUMMARIES: A 40-year-old black female received eptifibatide 180-μg/kg double bolus followed by a continuous infusion of 2 μg/kg/min for percutaneous coronary intervention (PCI). The platelet count decreased from 308 times 103/mm3 to 2 times 103/mm3 4 hours after initiation of eptifibatide. Eptifibatide was discontinued and platelets were transfused. The patient developed a hematoma and petechiae. A 67-year-old white female received the same dosage regimen of eptifibatide for PCI with no serious adverse effects, with the treatment repeated one month later. At that time, she developed chest and back pain, dyspnea, wheezing, and hypotension after the first bolus. Her platelet count decreased from 334 times 103/mm3 to 6 times 103/mm3 24 hours after initiation. Eptifibatide was discontinued and platelets were transfused. The patient died due to shock. A 72-year-old white male received eptifibatide 180-μg/kg double bolus followed by a continuous infusion of 2 μg/kg/min for acute coronary syndrome. His platelet count decreased from 189 times 103/mm3 to 17 times 103/mm3, and eptifibatide was discontinued. Eptifibatide was readministered with bivalirudin for PCI once the platelet count increased to 94 times 103/mm3. Sixteen hours later, the platelet count decreased to 1 times 103/mm3. Eptifibatide was discontinued and platelets were transfused. The patient developed a hematoma. DISCUSSION: Acute, profound thrombocytopenia is a rare complication of glycoprotein IIb/IIIa inhibitor therapy characterized by a precipitous decline in platelet count to <20 times 103/mm3 within 24 hours of therapy. An objective causality assessment revealed that the adverse drug event was probable in 2 cases and possible in the other. CONCLUSIONS: Increasing use of the glycoprotein IIb/IIIa inhibitors and enhanced recognition of the potential for acute, profound thrombocytopenia reinforce the need for more vigilant monitoring and alternative management strategies.
Methemoglobinemia Secondary to Topical Benzocaine Use in a Lung Transplant Patient
Authors: LeClaire Aimée C , Mullett Timothy W , Jahania M Salik , Flynn Jeremy D 
Published: January 2005

OBJECTIVE: To report a case of methemoglobinemia secondary to the administration of topical benzocaine spray in an anemic patient who had previously undergone a lung transplant. CASE SUMMARY: A 40-year-old white man with a past medical history significant for lung transplant acutely decompensated following oropharyngeal administration of topical benzocaine spray. Subsequent blood analysis revealed a methemoglobin concentration of 51.2%. Following the administration of a single dose of methylene blue 2 mg/kg intravenously, the patient's respiratory status dramatically improved and stabilized. DISCUSSION: Methemoglobinemia is a rare but potentially fatal condition that may be either acquired or congenital; however, the disorder is most commonly acquired secondary to exposure to oxidizing chemicals, which are often routinely prescribed medications, including benzocaine. Benzocaine can react with hemoglobin to form methemoglobin at a rate that exceeds reduction capabilities, which may result in oxygenation difficulty and respiratory distress. In severe or symptomatic methemoglobinemia, the treatment of choice is methylene blue. CONCLUSIONS: Application of the Naranjo probability scale established a highly probable relationship between topical benzocaine spray and methemoglobinemia and associated respiratory compromise. The risks of palliative use of topical benzocaine in patients with preexisting disorders that compromise oxygen delivery may outweigh any benefit. In our patient, anemia and lung disease increased his risk for clinically significant adverse respiratory events secondary to deficiencies or interferences in oxygen delivery. Topical benzocaine should be administered with caution and careful monitoring in such patient populations.
Interaction Between Dexamethasone Treatment and the Corticotropin Stimulation Test in Septic Shock
Authors: Bower Amy N , Oyen Lance J 
Published: January 2005

OBJECTIVE: To review dexamethasone interaction with corticotropin stimulation testing, particularly as it applies to treating septic shock. DATA SOURCES: Pertinent literature was identified through MEDLINE (1966–February 2004) using combinations of the key words dexamethasone, adrenocorticotropic hormone stimulation, and pretreat. Only articles written in the English language and evaluating human subjects were considered. Reference lists of identified articles were reviewed for additional citations. DATA SYNTHESIS: Accurate interpretation of the corticotropin stimulation test is important to identify patients with septic shock who may benefit from corticosteroid supplementation. In healthy volunteers, short-term dexamethasone administration prior to the corticotropin stimulation test may depress the baseline cortisol level, but does not inhibit the response to the corticotropin challenge. This may result in a slight increase in the difference between baseline and post-stimulation values. CONCLUSIONS: In 2 small trials in healthy adults, short-term, low-dose dexamethasone pretreatment decreased baseline cortisol levels, but values following corticotropin stimulation were unaffected. Accordingly, caution in interpreting corticotropin stimulation test results is warranted. However, the application of the findings from these studies to patients with septic shock is difficult, given the important differences in physiology between normal and septic patients. As of December 29, 2004, a dexamethasone dose >2 mg or prolonged dexamethasone therapy (>2 days, totaling 4 mg) preceding corticotropin stimulation has not been studied in any population.
Health Food Stores' Recommendations for Nausea and Migraines During Pregnancy
Authors: Buckner Kaitlin D , Chavez Mary L , Raney Erin C , Stoehr James D 
Published: January 2005

BACKGROUND: Many pregnant women use dietary supplements during pregnancy; however, relatively scant information is available on the safety of these products. Consumers of dietary supplements often rely on employees of health food stores to provide recommendations. OBJECTIVE: To evaluate recommendations made by health food store employees in the Phoenix metropolitan area regarding treatment of nausea/vomiting and migraines during pregnancy. METHODS: Phone calls were made by a disguised shopper to 155 health food stores in the greater Phoenix area. The caller posed as a woman 8 weeks' pregnant asking for recommendations for treatment of nausea/vomiting and migraines. Responses and recommendations were recorded and then compared with current scientific evidence obtained during a search of the literature using MEDLINE (1966–September 2004) as to whether or not the supplements and the methods of their use during pregnancy were contraindicated. RESULTS: Eighty-nine percent of stores offered recommendations for nausea/vomiting, and 82% provided recommendations for migraines. The use of ginger was the most recommended therapy for nausea/vomiting. Only 3.6% of respondents recommended correct usage, but failed to supply the correct dosage and duration. A total of 15 of 278 (5%) recommendations, for both nausea/vomiting and migraines, were for products contraindicated in pregnancy. CONCLUSIONS: In light of the increased use of dietary supplements by women during pregnancy, the willingness of personnel in health food stores to make any recommendations should foster concerns by patients and healthcare providers alike. Use of dietary supplements contraindicated in pregnancy could cause significant harm to the mother and/or fetus. Studies are needed to address the need for more stringent guidelines regarding health food stores and their recommendations.
Dystonia Induced by Gabapentin
Authors: Pina Miguel A , Modrego Pedro J 
Published: January 2005

OBJECTIVE:To report a case of dystonia as an adverse effect of gabapentin.CASE SUMMARY:A 72-year-old woman was diagnosed with essential tremor and treated with propranolol 120 mg daily. The drug was withdrawn because of bradycardia, and gabapentin was prescribed 3 times a day at escalating doses to reach 2100 mg daily. The woman developed a dystonic reaction involving muscles of the neck and both arms that resolved rapidly after drug withdrawal. She was restarted on gabapentin with slow titration to 1800 mg daily, but the same dystonic reaction appeared, which led to definitive withdrawal of the drug. An objective causality assessment revealed that this adverse effect was highly probable.DISCUSSION:There have been only a few previous reports of gabapentin-induced dystonia. Other movement disorders reported with gabapentin include myoclonus, ataxia, and choreoathetosis. Gabapentin has been used to treat dystonias with variable results.CONCLUSIONS:Although gabapentin is widely used and well tolerated, it can cause dystonic reactions, which are reversible after drug withdrawal.
Possible Warfarin Interaction with Menthol Cough Drops
Authors: Kassebaum Paul J , Shaw Don L , Tomich Dave J 
Published: January 2005

OBJECTIVE: To report a case of possible interaction of menthol cough drops (Halls) with warfarin in a patient awaiting cardioversion. CASE SUMMARY: A 57-year-old white male awaiting cardioversion for atrial fibrillation was prescribed warfarin. His dosage was adjusted to 7 mg daily to provide stable international normalized ratio (INR) values of 2.28–2.68. Approximately one week later, his INR fell to 1.45. During a follow-up interview, the patient reported that he experienced a flu-like illness during the previous week and had been using menthol cough drops. No other potential causes for the decreased INR were found. Illness will most often elevate the INR; we therefore concluded that the cough drops were the likely cause of this reaction, and the warfarin dose was increased to 53 mg/wk. After discontinuing use of menthol cough drops, the warfarin dose was returned to the previous amount and the INR remained stabilized. DISCUSSION: An objective causality assessment suggests that the decreased INR was possibly related to the use of menthol cough drops during warfarin therapy. The active ingredient in these cough drops is menthol. Menthol has been shown to affect the pharmacokinetics of other drugs by inducing or inhibiting cytochrome P450 isoenzymes and slowing drug absorption. It is not clear whether these mechanisms played a role in this case. As of January 5, 2005 this is the first case report documenting an interaction between warfarin and cough drops containing menthol. CONCLUSIONS: This case documents a significant decrease in the INR following the use of menthol cough drops. Patients who are ill have several factors that can potentially affect their INR and should be monitored closely.
Glutamatergic Innervation of the Heart Initiates Retrograde Contractions in AdultDrosophila melanogaster
Authors: Dulcis Davide , Levine Richard B. 
Published: January 2005

The adult abdominal heart ofDrosophila melanogasterreceives extensive innervation from glutamatergic neurons at specific cardiac regions during metamorphosis. Here, we show that the neurons form presynaptic specializations, as indicated by the localization of synaptotagmin and active zone markers, adjacent to postsynaptic sites that have aggregates of glutamate IIA receptors. To determine the role of this innervation in cardiac function, we developed an optical technique, based on the movement of green fluorescent protein-labeled nerve terminals, to monitor heart beat in intact and semi-intact preparations. Simultaneous monitoring of adjacent cardiac chambers revealed the direction of contractions and allowed correlation with volume changes. The cardiac cycle is composed of an anterograde beat in alternation with a retrograde beat, which correlate respectively with systole and diastole of this multichambered heart. The periodic change in hemolymph direction is referred to as cardiac reversal.Intracellular recordings from muscles of the first abdominal cardiac chamber, the conical chamber, revealed pacemaker action potentials and the excitatory effect of local glutamate application, which initiated retrograde contractions in semi-intact preparations. Unilateral electrical stimulation of the transverse nerve containing the glutamatergic neuron that serves the conical chamber caused a chronotropic effect and initiation of retrograde contractions. This effect is distinct from that of peripheral crustacean cardioactive peptide (CCAP) neurons, which potentiate the anterograde beat. Cardiac reversal was evoked pharmacologically by sequentially applying CCAP and glutamate to the heart.