bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal height and the outcome of labor in rural Tanzania
Authors: van Roosmalen J. , Brand R.
Published: May 2004

The influence of maternal height (standardized for parity and birth weight) on obstetrical outcome is studied in 1095 women giving birth in Lugarawa hospital and 3869 women delivering in Mbozi hospital, both rural hospitals in the South Western Highlands of Tanzania. Short stature was found to increase the need for augmentation of labor in primiparae, the need for operative delivery (cesarean section/symphyseotomy) in all parity groups and the need for vacuum extraction in multiparae. The absence of such an effect of height on perinatal mortality is interpreted as the result of obstetric intervention. It is concluded that maternal height, which is easy to measure, remains a useful tool to predict difficult childbirth and cephalopelvic disproportion.
Health and economic consequences of septic induced abortion
Authors: Konje J.C. , Obisesan K.A. , Ladipo O.A.
Published: May 2004

Over a period of 7 years, 230 cases of illegally induced abortions complicated by sepsis were treated at the University College Hospital, Ibadan, Nigeria. The number of terminations complicated by sepsis doubled from 25.4 (between 1981 and 1985) to 51.0 (between 1986 and 1987) cases per year. Peritonitis was the commonest associated complication while maternal mortality was 8.3%. The average cost of treatment was US$223.11, while the average monthly earnings was US$45.00. Legalization of abortion would have resulted in a saving of US$50 022.28. Provision of legal abortion would reduce the incidence of sepsis after termination while reproductive health education and information dissemination and provision of easily accessible family planning services would greatly reduce the number of unwanted pregnancies.
Giant broad ligament leiomyoma
Authors: Gowri V. , Sudheendra R. , Oumachigui A. , Sankaran V.
Published: May 2004

Giant fibroids are known to arise from the uterus, but occasionally from the broad ligament also. A case of giant broad ligament fibroid is reported for its rarity, and the diagnostic difficulties it posed are discussed.
Eclampsia: 134 consecutive cases
Authors: Obed S.A. , Wilson J.B. , Elkins T.E.
Published: May 2004

OBJECTIVE: A retrospective analysis of all cases of eclampsia (134) at Korle Bu Teaching Hospital, Accra, Ghana, in 1991, was undertaken to determine future directions in prevention and management. METHODS: One hundred and thirty‐four consecutive cases of eclampsia were reviewed to assess possible risk factors, associated medical impact, and the usefulness of prenatal care. RESULTS: Risk factors for the development of eclampsia include: young age, delivery in the rainy season, nulliparity, multiple pregnancy, prolonged labor, and lack of prenatal care. Eclampsia is associated with high maternal and perinatal mortality. CONCLUSIONS: Future emphasis on prenatal clinics, and earlier detection and management of pre‐eclampsia should lessen the incidence of this severe obstetric emergency.
Chemiluminescence immunoassay versus radioimmunoassay for the measurement of reproductive hormones
Authors: Rojanasakul A. , Udomsubpayakul U. , Chinsomboon S.
Published: May 2004

OBJECTIVES: To compare the hormonal values determined by chemiluminescence immunoassay (CIA) and radioimmunoassay (RIA). METHODS: Blood samples, drawn from eight volunteers during one menstrual cycle, were assayed for estradiol, progesterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin by CIA and RIA methods. The values obtained from these two assay techniques were compared. Statistical analysis were performed using the t‐test, Pearson correlation coefficient and simple linear regression analysis. RESULTS: CIA yielded lower mean values of LH, FSH, progesterone, but higher mean values of prolactin than RIA. Mean estradiol levels assayed by the two methods were similar. There was a good correlation between the hormonal values performed by the two methods. By calculation, the CIA hormonal value could accurately predict the RIA value by 96.6, 93.9, 89.9 and 66.0% for progesterone, LH, FSH and prolactin, respectively. CONCLUSIONS: The disparity in the hormonal values obtained from different assay methods warrants clinicians to be aware of their clinical interpretation. Using the same reference range for different assay methods is not appropriate. A comparative study between the new and standard assays is essential.
Trends in maternal mortality at a university hospital in Turkey
Authors: Ayhan A. , Bilgin F. , Tuncer Z.S. , Tuncer R. , Yanik A. , Kişnisçi H.A.
Published: May 2004

OBJECTIVE: To highlight recent trends in maternal mortality in Hacettepe University Hospital. METHOD: A retrospective clinical analysis of 117 maternal deaths between 1968 and 1992. RESULTS: The overall maternal mortality ratio was 180/100 000 (108/59 993). In terms of 5‐year periods, the maternal mortality ratio declined from 417.7 in 1968‐72 to 73.7 in 1988‐92. Infection was the most common cause of death (59.8%), followed by cardiac disease (8.5%) and hemorrhage (8.5%). Infection related deaths were either due to septic abortion (75.7%) or puerperal sepsis (24.3%). While 73.9% of all deaths were due to infection in 1968‐72, this figure contributed only 9.1% of the deaths in 1988‐92. When infection, hemorrhage, cardiac disease ad toxemia are investigated together, percentages of their contribution varies from 95.7% in 1968‐72 to 54.5% in 1988‐92 period. CONCLUSIONS: Maternal mortality ratios are decreasing significantly in our institution. An another promising finding is the further reduction in direct causes especially in recent years. However, an improvement in the care of pregnant women is necessary to continue this declining trend.
Epidural anesthesia in early compared with advanced labor
Authors: Ohel G. , Harats H.
Published: May 2004

OBJECTIVES: To examine whether continuous lumbar epidural analgesia administered in the early phase of labor leads to an increased incidence of instrumental vaginal deliveries. METHODS: In a retrospective analysis we have studied 563 consecutive term cephalic vaginal deliveries where an epidural was given for pain relief in labor. The type of delivery was compared in two groups. In Group 1 epidurals were given when the cervix was 3 cm or less dilated; in Group 2 when they were greater than 3 cm dilated. RESULTS: There was no difference in the incidence of instrumental deliveries in the two groups. Other variables including station of the fetal head, premature rupture of membranes, meconium, and administration of pitocin and pethidine did not effect these results. CONCLUSIONS: There is no justification in delaying epidural analgesia in labor when it is clinically indicated.
Danazol influences gonadotropin secretion acting at the hypothalamic level
Authors: Panidis D. , Vavilis D. , Rousso D. , Stergiopoulos K. , Kalogeropoulos A.
Published: May 2004

OBJECTIVES: The purpose of the study was to determine the influence of danazol on gonadotropin secretion. METHODS: Ten endometriotic patients were treated with danazol for 6 months. To evaluate gonadotropin and estradiol secretion, a gonadotropin‐releasing hormone (GnRH) test and a clomiphene citrate (CC) challenge test were carried out in the follicular phase before treatment, during the sixth month of treatment and after the reappearance of the second menses. The same tests were also performed, only once, in the follicular phase of ten normal women. RESULTS: GnRH‐stimulated gonadotropin response during danazol treatment was significantly higher than that in the same group of women before and after danazol treatment, as well as in controls. Gonadotropin increase after clomiphene citrate administration during danazol treatment was not significant; moreover, LH response was significantly lower than that in the same group of patients before and after danazol treatment, as well as in controls. CONCLUSIONS: Our results suggest that danazol exerts a suppressive effect on gonadotropin secretion acting at the hypothalamic level.
Endocrine profile of women with amenorrhea and oligomenorrhea
Authors: Seshadri L. , John S. , George S.S. , Seshadri M.S.
Published: May 2004

OBJECTIVES: To find out the common causes of amenorrhea and oligomenorrhea in south Indian women and to draw up a protocol for evaluation of women with these problems. METHODS: A retrospective study of 426 women with amenorrhea and oligomenorrhea was carried out. RESULTS: Forty‐one patients had primary amenorrhea, 132 had secondary amenorrhea and 289 women presented with oligomenorrhea. Hypergonadotropic amenorrhea and congenital absence of the uterus and vagina accounted for 60% of primary amenorrhea. Chronic anovulatory disorders and premature ovarian failure were found in 72% of women with secondary amenorrhea but weight loss related amenorrhea was uncommon. CONCLUSIONS: On the basis of the observations made, a protocol for evaluation and management of women with amenorrhea and oligomenorrhea was evolved.
A time and cost analysis of the management of incomplete abortion with manual vacuum aspiration
Authors: Blumenthal P.D. , Remsburg R.E.
Published: May 2004

OBJECTIVES: Traditionally, management of incomplete abortion involves use of D&C or suction curettage in the operating room. Such management is costly and time‐consuming. In order to potentially save time and money, we studied the use of manual vacuum aspiration curettage (MVAC) for the management of this problem. METHODS: Data on hospital charges and times (e.g. waiting time, procedure time) were obtained for all cases of incomplete abortion presenting to hospital between January 1990 and July 1992. Between January 1990 and July 1991, all cases were managed traditionally. After July 1991, all cases were managed using MVAC in either the emergency room or the labor ward. RESULTS: Compared to the use of electrical suction equipment in the operating theatre, MVAC procedures resulted in significant savings in terms of both waiting times and costs. Waiting time was reduced by 52% and procedure time was reduced from a mean of 33 min to 19 min (P < 0.01). Total hospital costs were reduced by 41% (P < 0.01). CONCLUSIONS: Use of manual vacuum aspiration curettage in the management of incomplete abortion can reduce hospital costs and save time for both patients and clinicians.
Attempting pregnancy after miscarriage and curettage — what is the minimum interval?
Authors: Ali S.M.T. , Hecht B.R.
Published: May 2004

We describe a normal pregnancy that was conceived less than 3 weeks following curettage for a blighted ovum. A delay between curettage and subsequent pregnancy is often recommended. Evidence supporting such a delay is examined.
Isolation and characterization of anti‐HIV peptides from Dorstenia contrajerva and Treculia obovoidea
Authors: Bokesch Heidi R. , Charan Romila D. , Meragelman Karina M. , Beutler John A. , Gardella Roberta , O'Keefe Barry R. , McKee Tawnya C. , McMahon James B.
Published: May 2004

Using a high throughput screen based on the interaction of the HIV‐1 gp41 ectodomain with the virucidal protein cyanovirin‐N (CV‐N), we isolated two new peptides which inhibited the binding of CV‐N to gp41 and which subsequently showed anti‐HIV activity in a whole cell assay. A 5‐kDa (contrajervin) and 10 kDa (treculavirin) peptide were isolated from Dorstenia contrajerva and Treculia obovoidea, respectively. Treculavirin was composed of two subunits, each containing 50 amino acid residues, which are covalently linked by at least one disulfide bond between the subunits. Both peptides were shown to bind to gp41 and gp120 and to inhibit the cytopathic effects of HIV‐1RF infection in a human T‐lymphoblastoid cell line (CEM‐SS).
Dimensions of informed consent to treatment
Authors: Dickens B.M. , Cook R.J.
Published: May 2004

Modern law approaches patients’ consent to treatment not only through liability for unauthorized touching, namely criminal assault and/or civil (non‐criminal) battery, but also through liability for negligence. Physicians must exercise appropriate skill in conducting procedures, and in providing patients with information material to the choices that patients have to make. The doctrine of informed consent serves the ethical goal of respecting patients’ rights of self‐determination. Information is initially pitched at the reasonable, prudent person in the patient's circumstances, and then fine‐tuned to what is actually known about the particular patient's needs for information. Elements to be disclosed include the patient's prognosis if untreated, alternative treatment goals and options, the success rate of each option, and its known effects and material risks. Risks include medical risks, but also risks to general well‐being such as economic and similar reasonable interests. Consent is a continuing process, not an event or signed form.
Oxygen isotopes of bovid teeth as archives of paleoclimatic variations in archaeological deposits of the Ganga plain, India
Authors: Sharma Shikha , Joachimski Michael M , Tobschall Heinz J , Singh Indra B , Tewari Devi P , Tewari Rakesh
Published: May 2004

Oxygen isotope analysis was performed on enamel phosphate of mammalian teeth from archaeological sites Kalli Pachchhim and Dadupur in the central Ganga plain and Charda in the northern Ganga plain. The bulk oxygen isotopic compositions of enamel phosphate from third molars (M3) of Bos indicus individuals belonging to different cultural periods were used to understand the climatic changes during the past 3600 cal yr B.P. Oxygen isotope ratios indicate humid conditions around 3600 cal yr B.P., followed by a trend toward drier conditions until around 2800 cal yr B.P. Then from 2500 to 1500 cal yr B.P. there is a trend toward higher humidity, followed by the onset of a dry period around 1300 cal yr B.P. The study of intratooth δ18O variations in teeth from different periods demonstrates that the monsoon seasonality was prominent. Spatial changes in the amount of annual rainfall are also reflected in the δ18O values. Teeth derived from areas with intense rainfall have lighter isotope ratios compared to teeth from regions receiving less rain, but they show similar seasonal patterns. The long-term paleoclimatic variations reflected by fluctuations in bulk δ18Op values from M3 teeth match well with the regional paleoenvironmental records and show a good correlation to the cultural changes that took place during this time span in Ganga plain.
Impacts of climate change on streamflow in the Upper Mississippi River Basin: A regional climate model perspective
Authors: Jha Manoj , Pan Zaitao , Takle Eugene S. , Gu Roy
Published: May 2004

Impact of climate change on streamflow in the Upper Mississippi River Basin is evaluated by use of a regional climate model (RCM) coupled with a hydrologic model, Soil and Water Assessment Tool (SWAT). The RCM we used resolves, at least partially, some fine‐scale dynamical processes that are important contributors to precipitation in this region and that are not well simulated by global models. The SWAT model was calibrated and validated against measured streamflow data using observed weather data and inputs from the U.S. Environmental Protection Agency Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) geographic information systems/database system. Combined performance of SWAT and RCM was examined using observed weather data as lateral boundary conditions in the RCM. The SWAT and RCM performed well, especially on an annual basis. Potential impacts of climate change on water yield and other hydrologic budget components were then quantified by driving SWAT with current and future scenario climates. Twenty‐one percent increase in future precipitation simulated by the RCM produced 18% increase in snowfall, 51% increase in surface runoff, and 43% increase in groundwater recharge, resulting in 50% net increase in total water yield in the Upper Mississippi River Basin on an annual basis. Uncertainty analysis showed that the simulated change in streamflow substantially exceeded model biases of the combined modeling system (with largest bias of 18%). While this does not necessarily give us high confidence in the actual climate change that will occur, it does demonstrate that the climate change “signal” stands out from the climate modeling (global plus regional) and impact assessment modeling (SWAT) “noise.”
On the relationship between Stokes parameters Q and U of atmospheric ultraviolet/visible/near‐infrared radiation
Authors: Schutgens N. A. J. , Tilstra L. G. , Stammes P. , Bréon F.‐M.
Published: May 2004

On the basis of both spaceborne measurements (Polarization and Directionality of the Earth's Reflectances (POLDER)) and radiative transfer modeling, it is shown that the polarization of reflected solar light (300–900 nm) at the top of the atmosphere is most often perpendicular and less often parallel to the plane of single scattering. In terms of the elements of the Stokes vector, ∣U∣ is typically much smaller than ∣Q∣ when using the single‐scattering plane as reference. When using any other plane, U(λ) ≈ Q(λ) tan 2χss, with χss being the angle of the plane of polarization with the reference plane in the case of single Rayleigh scattering. Exceptions to these findings are noted, and an error analysis of U(λ) ≈ Q(λ) tan 2χss is presented. A simplified polarization calibration algorithm for spaceborne spectrometers like the Spectrometer for Atmospheric Cartography (SCIAMACHY) is presented using the U‐Q relation studied in this paper. It is shown to be just as accurate but less sensitive to measurement error than the current operational algorithm.
Improving source identification of fine particles in a rural northeastern U.S. area utilizing temperature‐resolved carbon fractions
Authors: Kim Eugene , Hopke Philip K.
Published: May 2004

Integrated, 24‐hour, ambient PM2.5 (particulate matter ≤2.5 μm in aerodynamic diameter) samples were collected at a rural monitoring site in Brigantine, New Jersey, on Wednesdays and Saturdays using Interagency Monitoring of Protected Visual Environments (IMPROVE) samplers. Particulate carbon was analyzed using the thermal optical reflectance method, which divides carbon into four organic carbon (OC), pyrolyzed organic carbon (OP), and three elemental carbon (EC) fractions. A total of 910 samples and 36 variables collected between March 1992 and May 2001 were analyzed using positive matrix factorization, and 11 sources were identified: sulfate‐rich secondary aerosol I (48%), gasoline vehicle (13%), aged sea salt (8%), sulfate‐rich secondary aerosol II (7%), nitrate‐rich secondary aerosol (6%), sulfate‐rich secondary aerosol III (5%), sea salt (4%), airborne soil (4%), diesel emission (3%), incinerator (2%), and oil combustion (1%). Temperature‐resolved carbon fractions enhanced source separations including three sulfate‐rich secondary aerosols and two traffic‐related sources that had different abundances of carbon fractions different between sources. Conditional probability functions using surface wind data and deduced source contributions aid in the identification of local sources. Potential source contribution function (PSCF) analysis shows the regional influence of sulfate‐rich secondary aerosols. Backward trajectories indicate that the highly elevated airborne soil impacts at the monitoring site were likely caused by either Asian or Sahara dust storms.
Backazimuth estimation reliability using surface wave polarization
Authors: Baker G. Eli , Stevens Jeffry L.
Published: May 2004

Backazimuth estimates derived from surface wave polarization can be used to test association of an observed surface wave with a seismic event. However, commonly used techniques for estimating the backazimuth are subject to a number of errors and are often inaccurate. We evaluate the performance of a new algorithm for determining Rayleigh wave propagation direction from the cross‐correlation of the horizontal and Hilbert transformed vertical seismograms. This proves to be more accurate and much less error‐prone than current automatic processing procedures, and the cross‐correlation value provides a good measure of the reliability of the backazimuth estimate. Consequently, the new algorithm will permit more reliable event association at a lower magnitude threshold.
Experiments on magma mixing
Authors: Zimanowski Bernd , Büttner Ralf , Koopmann Anselm
Published: May 2004

The arrival of a new hot batch of magma changes the thermal and the chemical state of a volcanic plumbing system. Formation of hybrid magma by chemical dilution (liquid miscibility model) of different magma batches is generally accepted. Observations of drop‐like domains of less evolved (newer) magma in more evolved (host) magma point to the contribution of a mechanical mixing process (liquid immiscibility). The interplay of both mechanisms seems to control the time scale from the dormant to the active state of a volcano. We carried out laboratory experiments using melts from natural volcanic rock compositions with the aim to validate model calculations for shear rate dependent domain sizes. The results confirmed the model and also the importance of hydro‐mechanically mixing for chemical dilution. The key process, however, that is able to change the state of a magma reservoir on a critical time scale is hydrodynamic magma mixing.
A massive dissolved inorganic carbon release at spring tide in a highly turbid estuary
Authors: Abril Gwenaël , Commarieu Marc‐Vincent , Maro Denis , Fontugne Michel , Guérin Frédéric , Etcheber Henri
Published: May 2004

In September 2003, the highly turbid Loire estuary (France) showed drastic oxygen depletions (down to 11% of saturation), high pCO2 (up to 3740 μatm) and high CO2 fluxes (280 ± 100 mmol.m−2.d−1). A rapid rise in Dissolved Inorganic Carbon (DIC) was observed when the tidal amplitude increased from 3.8 m to 5.8 m. In two days, average concentrations in the 0.1–25 salinity range increased by 106 ± 17 μmol.kg−1 for DIC, by 80 ± 14 μeq.kg−1 for Total Alkalinity (TA) and by 684 ± 142 μatm for pCO2. In parallel, oxygen decreased by 65 ± 12 μmol.kg−1. These changes in concentrations were attributed in majority to a massive fluid mud resuspension in the estuarine turbidity maximum. At spring tide, this DIC input was 30% higher than the river input. When averaged over the neap‐spring period, resuspension contributed to only 10% of the atmospheric CO2 flux from the estuary, but to 60% to the net TA production in the estuary.
Inescapable slow slip on the Altyn Tagh fault
Authors: Wallace Kali , Yin Guanghua , Bilham Roger
Published: May 2004

GPS surveys conducted in 1994, 1998, and 2002 on the central portion of the Altyn Tagh fault confirm left‐lateral slip rates of 9 ± 4 mm/yr, significantly slower than geological estimates of slip rate for the past several thousand years. The measurements were obtained on a 300‐km‐long profile between 88° and 91°E within one fault dimension of the Mw = 7.6 and Mw = 7.8 Kunlun earthquakes of 1997 and 2001. The inferred elastic displacements from these events are incorporated into the interpreted 1994–2002 velocity field. The recent serendipitous occurrence of these two large earthquakes on a sub‐parallel fault system suggests that slip on the Kunlun fault may have recently accelerated, thereby reducing the slip rate on the Altyn Tagh fault. However, geodetic data from northern Tibet prior to the 2001 earthquake indicate present‐day rates similar to long term rates. This suggests that systematic errors may be present in published geologic slip rate estimates for the Altyn Tagh fault.
Imaging the structure of a large‐scale TID using ISR and TEC data
Authors: Nicolls Michael J. , Kelley Michael C. , Coster Anthea J. , González Sixto A. , Makela Jonathan J.
Published: May 2004

Here we present North American observations of the 3‐dimensional structure of large‐scale traveling ionospheric disturbances (TIDs) that affected the low‐ and mid‐latitude ionosphere during the stormtime period of October 1–2, 2002. Using TEC data from the American network of dual‐frequency GPS receivers, we are able to examine the effect of the TIDs on the background TEC and thus image their horizontal scales. Incoherent scatter radar data from the Arecibo Observatory give information on the vertical structure of the disturbances. The meridional and zonal structure of the TIDs are explored by computing the TEC perturbation, a method which has a resolution of a fraction of a TEC unit. The technique is effective in mapping the global structure of large‐scale disturbances, as the lower latitude perturbations can be examined at the same time as the higher latitude sources. The method may prove valuable in studying the formation and propagation of TIDs.
Interaction of Flooding with Carbon Metabolism of Forest Trees
Authors: Kreuzwieser J. , Papadopoulou E. , Rennenberg H.
Published: May 2004

Abstract:Waterlogging and flooding cause oxygen deprivation in the root system of trees. Since oxygen is essentially for mitochondrial respiration, this process cannot be maintained under anoxic conditions and must be replaced by other pathways. For the roots it is therefore a matter of survival to switch from respiration to alcoholic fermentation. Due to the low efficiency of this process to yield energy equivalents (ATP), energy and carbon metabolism of trees are usually strongly affected by oxygen deprivation, even if a rapid switch from respiration to fermentation is achieved. The roots can compensate for the low energy yield of fermentation either (1) by decreasing the demand for energy by a reduction of energy‐dependent processes such as root growth and/or nutrient uptake, or (2) by consuming more carbohydrates per unit time in order to generate sufficient energy equivalents. In the leaves of trees, flooding and waterlogging cause a decline in the rates of photosynthesis and transpiration, as well as in stomatal conductance. It is assumed that, due to reduced phloem transport, soluble sugars and starch accumulate in the leaves of flooded trees, thereby negatively affecting the sugar supply of the roots. Thus, root growth and survival is negatively affected by both changes in root internal carbon metabolism and impaired carbon allocation to the roots by phloem transport. In addition, accumulation of toxic products of fermentation in the roots, such as acetaldehyde, can further impair root metabolism. A main feature of tolerance against flooding and waterlogging of trees seems to be the steady supply of carbohydrates to the roots in order to maintain alcoholic fermentation; in addition, roots of tolerant trees seem to avoid accumulation of fermentation‐derived ethanol and acetaldehyde. From studies with flooding tolerant and non‐tolerant tree species, it is hypothesized that (1) the transport of ethanol produced in the roots under hypoxic conditions into the leaves via the transpiration stream, (2) its conversion into acetyl‐CoA in the leaves, and (3) its use in the plant's general metabolism, are mechanisms of flooding tolerance of trees.
Hg2+ Reacts with Different Components of the NADPH: Protochlorophyllide Oxidoreductase Macrodomains
Authors: Solymosi K. , Lenti K. , Myśliwa‐Kurdziel B. , Fidy J. , Strzałka K. , Böddi B.
Published: May 2004

Abstract: The molecular background of Hg2+‐induced inhibition of protochlorophyllide (Pchlide) photoreduction was investigated in homogenates of dark‐grown wheat leaves. Our earlier work showed that 15 min incubation with 10‐2 M Hg2+ completely inhibits the activity of NADPH: Pchlide oxidoreductase. Detailed analysis of spectra recorded at 10 K indicated the appearance of emission bands at 638 and 650 nm, which are characteristic for NADP+‐Pchlide complexes. Fluorescence emission spectra recorded with different excitation wavelengths, fluorescence lifetime measurements and the analysis of acetone extractions revealed that Hg2+ can also react directly with Pchlide, resulting in protopheophorbide formation. At 10‐3 M Hg2+, the phototransformation was complete but the blue shift of the chlorophyllide emission band speeded up remarkably. This indicates oxidation of the NADPH molecules that have a structural role in keeping together the etioplast inner membrane components. We suggest a complex model for the Hg2+ effect: depending on concentration it can react with any components of the NADPH: Pchlide oxidoreductase macrodomains.
Results with the superconducting electron cyclotron resonance ion source VENUS (invited)
Authors: Lyneis C. M. , Leitner D. , Abbott S. R. , Dwinell R. D. , Leitner M. , Silver C. S. , Taylor C.
Published: May 2004

During the last year, the VENUS electron cyclotron resonance (ECR) ion source was commissioned at 18 GHz and preparations for 28 GHz operation, which is set to begin early in 2004, are now underway. The goal of the VENUS ECR ion source project as the RIA research and development injector is the production of 240 eμA of U30+, a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5 eμA of U48+, a low current, very high charge state beam. During the commissioning phase with 18 GHz, tests with various gases and recently metals have been performed with up to 2000 W rf power and the performance is very promising. For example, 1100 eμA of O6+, 180 eμA of Ar12+, 150 eμA of Xe20+, and 100 eμA of Bi24+ were produced in the early commissioning phase, ranking VENUS among the currently highest performance 18 GHz ECR ion sources. The emittance of the beams produced at 18 GHz was measured with a two axis emittance scanner. In FY04 a 10 kW, 28 GHz gyrotron system will be added, which will enable VENUS to reach full performance. The performance of the VENUS ion source, low energy beam transport and its closed loop cryogenic system are described in the article. Recently, a high temperature axial oven has been installed in the source and the first results on metal beams such as bismuth are given. The design of the 28 GHz, 10 kW gyrotron system will also be described.
Electron cyclotron resonance ion source developments in RIKEN (invited)
Authors: Nakagawa T. , Aihara T. , Higurashi Y. , Kidera M. , Kase M. , Yano Y. , Arai I. , Arai H. , Imanaka M. , Lee S. M. , Arzumanyan G. , Shirkov G.
Published: May 2004

We have constructed four high performance electron cyclotron resonance (ECR) ion sources in RIKEN and produced a variety of intense beams of heavy ions (e.g., 2 emA of Ar8+, 0.6 emA of Kr13+, 0.3 emA of Xe20+). During the improvement of their performance, we found that several key parameters play essential role on increasing the beam intensity. The parameters are plasma electrode position, magnetic field configuration, property of the chamber wall material and position of a biased disk. To investigate how the parameters influence on the beam intensity, we made a systematic study using the laser ablation method. In these experiments, we observed that Bmin influences the electron density and confinement time of ECR plasma.
Status report on ECR ion source operation at GANIL
Authors: Lehérissier P. , Barué C. , Canet C. , Dubois M. , Dupuis M. , Flambard J. L. , Gaubert G. , Jardin P. , Lecesne N. , Lemagnen F. , Leroy R. , Pacquet J. Y. , Pellemoine-Landré F.
Published: May 2004

Two electron cyclotron resonance ion sources, ECR 4 and ECR 4 M, provide high charge state beams to the compact cyclotrons, C01 and C02, which are alternative injectors for the GANIL cyclotrons CSS1 and CSS2. When an injector runs for a long period, the off-line source can be used for beam developments or, together with the off-line injector, deliver a beam to a new beam line, called IRRSUD, for atomic physics experiments. Various ions are requested for beam time for periods of 8 to 11 weeks. Although the majority of the required beams comes from gaseous elements, work on the production of beams of metallic ions is always a main activity. New ovens are being developed to improve the capacity and the performances of the standard micro-oven. The latest results with U238 beam, using sputtering method and Ge76 beam using recycling method, are reported here.
Development of 13 GHz compact electron cyclotron resonance ion source
Authors: Saitoh Y. , Ohkoshi K. , Arakawa K.
Published: May 2004

An extremely compact, all-permanent-magnet electron cyclotron resonance ion source was designed and manufactured mainly for materials development. The ion source was installed in a 400 kV ion implanter, and a heavy ion beam in the mega-electron-volt (MeV) energy region with high beam intensity was available using multiply charged ions from the ion source. The magnet measured 120 mm in length and 30 mm and 110 mm in inner and outer diameters, respectively. A high magnetic field in the plasma chamber was formed by the unique permanent magnet structure. The maximum and minimum mirror fields achieved were 0.62 and 0.40 T, respectively. Up to 10 W of 13 GHz microwave power was fed to the source by the solid-state microwave generator, and the minimum B structure was formed in the plasma chamber. In the preliminary result at the test stand, an O5+ beam of 11 eμA, an Ar4+ beam of 80 eμA, and a He2+ beam of 100 eμA were available and an Ar12+ beam of 10 eμA was obtained with microwave power of only 10 W. The beam performance of the new source and the previous 10 GHz source developed at TIARA were compared.
Analysis tools for multicharged and multispecies ion spectra
Authors: Cavenago M.
Published: May 2004

A systematic analysis of the charge state distribution (CSD) of each element (or isotope) X extracted from a highly charged ion source as a function of control variables or time needs properly automated tools for the large amount of data involved and the possibility of peak superposition, due to the mass separator properties. Some key features of identification of ion currents with the new program DAT2PEAK are discussed here. A preprocessor LECR2DAT reads files of experimental scans. To obtain a reliable identification of element X and charges i several filtering and calibration routines were necessary; principles of their robust algorithms are discussed. Moreover, the concept of constrained fit allows one to use information both from superposed peak and single ion peak and to select different fit laws of CSD for each element X. A robust rule to distribute the current of superposed peaks to related elements is also presented. For each measurement processed, DAT2PEAK produces a listing of peaks and CSDs and updates the history files for the convenience of following statistical analysis.
Experimental studies of the afterglow mode with xenon in a CAPRICE ECRIS
Authors: Tinschert K. , Iannucci R. , Bossler J. , Lang R.
Published: May 2004

At GSI the CAPRICE-type ECRIS delivers ion beams to the High Charge State Injector (HLI). Following the demand of high flexibility the ECRIS is operated either in cw mode for high duty cycle beams or in afterglow mode to provide low duty cycle beams for the Heavy Ion Synchrotron (SIS) at low repetition rates in the order of 1 pulse per second. Especially for high Z ions the afterglow mode can provide increased intensities with respect to cw mode in those charge states required for injection (A/q<8.5). Besides the required beam intensity major demands of accelerator injection are good long time stability and good pulse to pulse reproducibility of the ion beam. In order to find the best operating conditions for optimized afterglow performance systematic studies were performed with Xe136, the heaviest stable rare gas isotope. Different rf pulse conditions (pulse length, repetition rate, pulse shape, duty cycle) were compared. The influence of the ion source parameters on the afterglow mode were studied in comparison to cw mode.
Status of the light ion source developments at CEA/Saclay
Authors: Gobin R. , Beauvais P.-Y. , Bogard D. , Charruau G. , Delferrière O. , De Menezes D. , France A. , Ferdinand R. , Gauthier Y. , Harrault F. , Mattéi P. , Benmeziane K. , Leherissier P. , Paquet J.-Y. , Ausset P. , Bousson S. , Gardes D. , Olivier A. , Celona L. , Sherman J.
Published: May 2004

SILHI (High Intensity Light Ion Source) is an ECR ion source producing high intensity proton or deuteron beams at 95 keV. It is now installed in the IPHI site building, at the CEA/Saclay center. IPHI is a front end demonstrator of high power accelerator. The source regularly delivers more than 130 mA protons in cw mode and already produced more than 170 mA deuterons in pulsed mode at nominal energy. The last beam characterizations, including emittance measurements, space charge compensation analysis, and diagnostic improvements, will be reported. Taking into account the SILHI experience, new developments are in progress to build and test a 5 mA deuteron source working in cw mode. This new source will also operate at 2.45 GHz and permanent magnets will provide the magnetic configuration. This source, of which the design will be discussed, will have to fit in with the SPIRAL 2 accelerator developed at GANIL to produce radioactive ion beams. The H− test stand status is briefly presented here and detailed in companion papers.
2D modeling of electron distribution function in the ECR ion source
Authors: Erukhimov V. L. , Semenov V. E.
Published: May 2004

We propose a two-dimensional numerical model for the electron distribution function in electron cyclotron resonance (ECR) ion sources. ECR heating, collisions, ionization, and losses from the trap are taken into account. The model finds the electron distribution function dynamics in time rather than just a steady-state solution. ECR diffusion operator is calculated from a self-consistent solution of rf wave propagation through the ECR cross section. Losses are modeled with an ambipolar potential that is calculated from the electron distribution function. We have developed a numerical code ERVIS for solving this model.
Imaging of ECR plasmas with a pinhole x-ray camera
Authors: Biri S. , Valek A. , Suta T. , Takács E. , Szabó Cs. , Hudson L. T. , Radics B. , Imrek J. , Juhász B. , Pálinkás J.
Published: May 2004

X-ray plasma images were made at the 14.5 GHz electron cyclotron resonance ion source of ATOMKI using a pinhole and a high resolution CCD camera. This method has good spatial resolution as well as the capability of postprocessed energy filtering of the images. During the measurements low and high charge state Ar, Xe, and Fe plasmas were produced with simultaneous beam extraction. Full-size and selected region images were recorded and analyzed. Full-size x-ray images show the spatial positions of different sources of x rays (bremsstrahlung, characteristic lines of plasma and wall ions) within low-charged ECRIS plasmas. Images of selected plasma regions (extraction slit, magnet pole, magnet gap) offer a better understanding of the effect of important tuning parameters (bias disk voltage, gas mixing, microwave power, magnetic field strength, etc.) commonly used to produce highly charged plasmas and beams.
28 GHz 10 kW gyrotron system for electron cyclotron resonance ion source
Authors: Bykov Yu , Denisov G. , Eremeev A. , Gorbatushkov V. , Kurkin V. , Kalynova G. , Kholoptsev V. , Luchinin A. , Plotnikov I.
Published: May 2004

The 28 GHz gyrotron system (GS) has been purposely designed to meet present-day demand for a microwave source for powering an electron cyclotron resonance ion source capable of producing both high total current and high average ion charge. A gyrotron oscillator of GS operates in both continuous wave and pulse regimes with the output microwave power smoothly regulated in the (0.1–10) kW range. As a whole the functional structure of GS follows the general method of design for feedback controlled microwave sources. The fast feedback loop consists of microwave power detector unit, a purposely developed PC control system, and a high voltage power supply, the regulated voltage from which controls the gyrotron output power. The feedback characteristic time is less than 1 s. The accuracy of a pre-set microwave power maintenance in continuous wave operation of GS is better than 100 W at an output power of 10 kW, and about 50 W at a power of 1 kW. In pulse operation the pulse length can be varied in the range of (1–200) ms with a repetition rate of (200–1) Hz. The leading and trailing edges of the microwave power pulse are 100 μs and less than 10 μs, respectively. The high voltage power supply is furnished with a fast electronic protective system to provide long-term trouble-free operation of gyrotron. The developed PC microwave power control subsystem makes it possible to control the microwave power in both manual and automatic mode. On trials the developed gyrotron system proved itself as versatile, reliable, and user friendly tool applicable for long-term powering of ion sources.
Commissioning the TRIUMF/ISAC electron cyclotron resonance ion source for radioactive ion beams
Authors: Jayamanna K. , Yuan D. , Olivo M. , Baartman R. , Dutto G. , McDonald M. , Mitra A. , Schmor P. , Stanford G.
Published: May 2004

A radiation hard 2.45 GHz ECR source has been installed in the ISAC target station. The ion source with its 8–60 kV extraction system is coupled to the radioactive isotope production target via a short transfer tube. The volatile radioactive isotopes produced by bombarding a target with a 500 MeV proton beam, are ionized and accelerated at the ECR source system. The source is reengineered to withstand a dose rate of 105 Gy/h from the activation of the target by the 500 MeV, 100 mA proton beam. The whole assembly is located beneath a 2 m thick steel shielding structure. Design aspect of the source and the initial results obtained during the commissioning at the ISAC terminal, as well as preliminary results obtained at the test stand are presented.
The effects of gas mixing and plasma electrode position on the emittance of an electron cyclotron resonance ion source
Authors: Suominen P. , Tarvainen O. , Koivisto H.
Published: May 2004

Gas mixing is a commonly used method to improve the intensities and the charge state distribution of ion beams extracted from an electron cyclotron resonance ion source (ECRIS). At the same time, the emittance of the ion beam should be as small as possible. In this work we have studied the effect of the gas mixing method on the ion beam quality by measuring the emittance and brightness of different ion beams using helium, oxygen, and argon with several gas feeding ratios. All measurements were performed with the JYFL 6.4 GHz ECRIS. At the second stage of the experiments the emittance and the ion beam brightness were studied as a function of the plasma electrode position. The extraction system constructed for this experiment can be moved online.
Magnetic field upgrade of Argonne National Laboratory 14 GHz ECR ion source
Authors: Vondrasek R. C. , Scott R. , Pardo R. C.
Published: May 2004

The latest developments in superconducting electron cyclotron resonance ion sources (ECRIS), and in particular their capability to vary the hexapole field, have highlighted the importance of optimizing the magnetic field configuration for maximum beam production. With the presently accepted set of magnetic scaling rules serving as a guide, several aspects of the magnetic structure of the Argonne National Laboratory 14 GHz ECRIS (ECR2) have been upgraded. The injection region iron has been modified raising the peak injection side field from 1.7 to 2.0 T. In conjunction with the iron upgrade, the previously damaged hexapole has been replaced with a new permanent magnet hexapole constructed of higher-grade material. This has raised the wall field from 0.80 to 0.95 T. Thus, 250 e μA of Kr14+ and 7.0 e μA of Kr25+ have been measured. Results with lead include 102 e μA of Pb24+ and 6.4 e μA of Pb37+. Uranium has been produced using the sputter method resulting in 39 e μA of U26+, 30 e μA of U29+, and 1.1 e μA of U43+. These results in general represent a factor of 2 improvement over the preupgrade beam intensities.
Use of EBIS in the string mode of operation on the Nuclotron facility in JINR
Authors: Donets E. D. , Donets D. E. , Donets E. E. , Salnikov V. V. , Shutov V. B. , Gudkov S. V. , Tumanova Yu. A. , Vadeev V. P.
Published: May 2004

The reflex mode of EBIS operation in certain conditions (a special construction of electron gun and electron reflector, a precise axial symmetry of solenoid with a strong magnetic field, a sufficient injected electron current at a certain energy which provide a sufficient density of accumulated electrons in EBIS drift space) leads to formation of the so-called electron string state of a pure one component electron plasma. It was shown experimentally, that electron strings are stable in a broad range of operational conditions to be used for production of highly charged ions in electron string ion sources (ESIS) similarly to streaming electron beams in EBIS. The EBIS “Krion-2” in the string mode of operation, by means of which electron string formation was first observed and majority of experimental information on its features has been obtained, was recently used as the source of highly charged ions on the Nuclotron accelerator facility. During two runs in June 2002 and June 2003 N6+, N7+, Ar16+ and Fe24+ ions of 300, 350, 200, and 150 μA pulse current, respectively, produced by this source were accelerated to relativistic energies and used in several experiments. During the runs the source situated on the high voltage platform of the LINAC preinjector worked mostly in an automatic mode of operation and showed high stability and reliability.
Development of a vacuum arc ion source for injection of high current uranium ion beam into the UNILAC at GSI
Authors: Hollinger R. , Galonska M. , Spädtke P.
Published: May 2004

To fill up the GSI heavy ion synchrotron (SIS) to its space charge limit with uranium ions, a vacuum arc ion source, based on the metal vapor vacuum arc (MEVVA) IV ion source, has been developed and implemented into operation. The ion source has proven its capability in several long period beam times at the high current injector at GSI. With the ion source it was possible to exceed the space charge limit of 15 mA U4+ ions at the entrance of the linear accelerator (UNILAC). The reliability as well as the noise behavior has been improved to such a degree, that this ion source can be used for injection into an accelerator without objection. In this article we present the improvements of the ion source with the most important operational data. The emission current density of the ion source has been increased from 60 mA/cm2 for the common used GSI-MEVVA to 170 mA/cm2. This results in a full beam ion current of 156 mA at 35 kV with a fraction of fourfold charged uranium ions of 67%. The analyzed U4+ ion beam after dc postacceleration amounts to 25 mA at 131 kV which is 1.7 times higher than the requested ion beam current at the entrance of the radio frequency quadrupole. The reduced power density of the vacuum arc results in a higher efficiency and longer lifetime. Solenoids which are creating magnetic fields to enhance the charge state of the ions are no longer placed inside the vacuum system. This ion source design results in a higher availability after ion source replacement at the injector, and longer lifetime.
Generation of intense streams of metallic ions with a charge state up to 10+ in a laser ion source
Authors: Láska L. , Krása J. , Pfeifer M. , Rohlena K. , Gammino S. , Torrisi L. , Andò L. , Ciavola G.
Published: May 2004

The yield and the properties of Al, Au, Cu, Nb, Ni, Pb, Sn, Ta, and W ions from the plasma produced by a 0.9 J/9 ns Nd:YAG laser have been examined. Changing either the laser pulse energy or the focal spot size, the laser power density on the target surface was varied from 1×109 to about 1×1011 W/cm2, i.e., from the threshold power density for the ion generation up to the maximum laser intensities attainable with the setup used. The ion velocities (ion energies) ranged from about 2×106 to 2×107 cm/s (100 eV–10 keV) in dependence on the target element used and on the laser power density. The ion emission was peaked along the normal to the target surface; the angular distribution of ion velocities (energies) was not the same for all elements studied. Measured ion current densities ranged from 4 mA/cm2 (for Au) to 43 mA/cm2 (for Cu) at a distance of 44 cm from the target.