bluuebunny/crossref_metadata_2025_split huggingface dataset:
ONTOGENY OF SEXUAL CONCEPTACLES IN A SPECIES OF BOSSIELLA (CORALLINACEAE)1
Authors: Johansen H. William 
Published: August 2007

SUMMARYThe first evidence of conceptacle formation in male and female plants of Bossiella californica ssp. Schmittii is the secretion of a cap below the epithallium. Subsequent development involves the disintegration of the upper enucleate parts of cortical cells below the center of the cap concomitant with the growth of tissue surrounding these cells. Protoplasts in the lower parts of these cortical cells recover and become initials of reproductive cells. Differentiation of each initial in female plants results in a supporting cells bearing 1 or 2, 2‐celled carpogonial filaments, and in male plants results in a basal cell bearing 2 or 3 spermatangial mother cells which bud off spermatangia. Following fertilization, supporting cells fuse and form a broad, thin fusion cell from the upper surface of which gonimoblast (carposporangial) filaments arise.
NUTRITIONAL STUDIES ON THE CHLOROMONADOPHYCEAE: VACUOLARIA VIRESCENS AND GONYOSTOMUM SEMEN12
Authors: Heywood Peter 
Published: August 2007

SUMMARYUnialgal, nonaxenic cultures of Vacuolaria virestcens Cienkowsky were grown in soil‐water medium, in simple salt solutions with added peat and soil extract, and in synthetic medium. Doubling times in different media were determined: maximum growth rate (doubling time = 46.0 hr) was obtained in continuous light (210 ft‐c) at 24 ± I C. Gonyostomum semen (Ehrenberg) Diesing was isolated from a natural population and grown in soil‐water medium and a synthetic medium. Other techniques that have been used for culturing chloromonadophycean algae are reviewed.
OBSERVATIONS ON THE STRUCTURE OF SOME FORMS OFGOMPHONEMA PARVULUMKÜTZ. II. THE INTERNAL ORGANIZATION1
Authors: Dawson Penelope A. 
Published: August 2007

SUMMARYThe diatom speciesGomphonema parvulumKütz. was isolated, grown in culture, and the details of the internal organization studied by light and electron microscopy. The organism is usually identified from its frustular morphology, but members of the genusGomphonemacan be separated from other naviculoid forms by the H‐shaped chromatophore, whose lobes are connected on 3 sides across the center of the cell, and also from the position of the pyrenoid. This is situated, on the inner side of the chromatophore and is not embedded in the center of the chromatophore. New observations of this pennate diatom include details of the periplastidial network, of the Golgi vesicular activity, and of the storage products.
LIFE HISTORY STUDIES OF SELECTED BRITISH CERAMIUM SPECIES1
Authors: Edwards Peter 
Published: August 2007

SUMMARY Ceramium shuttleworthianum, C. rubrum, and C. pedicellatum demonstrated a Polysiphonia type of life history without deviations in unialgal culture. The reported absence of fertile gametophytic plants of C. shuttleworthianum and C. flabelligerum from northern Scotland in the northern part of their geographical ranges is probably attributable to the inhibition of gametangial production by the environment.
COMPARATIVE STUDIES OF PYRENOID ULTRASTRUCTURE IN ALGAE OF THE MONOSTROMA COMPLEX123
Authors: Hori Terumitsu 
Published: August 2007

SUMMARYThe pyrenoid structure in 15 species of the Monostroma complex is very diverse us revealed by a study of the morphology of the pyrenoid matrix, associated starch shell, and pattern of intrapyrenoidalthylakoid bands. From these characteristics 8 types of pyrenoid structure were classified. The variation of pyrenoid structure was shown not only among the species studied, but also between the alternation of generations (M. angicava and M. nitidum). In M. fuscum var. splendens, M. groenlandicum, M. undulatum, and M. zostericola pyrenoid structure is the same throughout the life cycle. The pyrenoid matrix of M. zostericola is surrounded by a double membrane that prevents the direct connection of the pyrenoid matrix with chloroplast thylakoids. The pyrenoid also lacks a starch shell. These findings support the establishment of a new genus Kornmannia by Bliding to include M. zostericola. In addition, similarities in pyrenoid ultrastructure suggest an affinity of Capsosiphon fulvescens with M. groenlandicum.
AN ELECTRON MICROSCOPIC STUDY OF THE SPOROPHYTIC AND GAMETOPHYTIC PLANTS OF PADINA VICKERSIAE HOYT1
Authors: Fagerberg Wayne R. , Dawes Clinton J. 
Published: August 2007

SUMMARYAn electron microscopic comparison was made of the “isomorphic” sporophytic and gametophytic plants of Padina vickersiae. Light microscopic studies of the 2 generations showed few differences. This observation was also supported by studies at the ultrastructural level. However, minor differences in the gametophytic plant have been noted: (1) a well‐defined nucleolus in the nucleus of the non‐meristematic cell; (2) a general lack of osmiophilic globules in the chloroplasts; and (3) a clumping of chloroplasts in the maturing oogonium. The first and second differences are considered in terms of growth activity.
THE LIFE CYCLE OF BANGIA FUSCOPURPUREA IN CULTURE. I. EFFECTS OF TEMPERATURE AND PHOTOPERIOD ON THE MORPHOLOGY AND REPRODUCTION OF THE BANGIA PHASE12
Authors: Sommerfeld Milton R. , Nichols H. Wayne 
Published: August 2007

SUMMARYThe Bangia phase of Bangia fuscopurpurea was grown in laboratory culture in a variety of photoperiod and temperature regimes. Plants of the Bangia phase grown from 2 types of asexual spores, monospores and conchospores, exhibited growth differences under similar growing conditions. Plants derived from monospores grew more rapidly and matured earlier than those derived from carpospores. Day length and temperature were found to significantly influence growth rule, maturation, and plant size. Long day lengths resulted in more rapid growth in filament length and diameter and earlier spore formation and spore release. Maximum filament length was observed in a 12/12 hr light‐dark cycle at 15 C. Spore formation and release were delayed by decreasing day length or temperature. Temperature and photoperiod were also found to influence the type of spores produced by the Bangia phase. When grown at 22 C, the Bangia phase produced only monospores, which reproduced the Bangia phase. At 9 C, with photoperiods of 11 hr or more of light, the Bangia phase produced carpospores which gave rise to the alternating Conchocelis phase. The conditions under which sporogenesis occurred determined the spore type differentiated.
ULTRASTRUCTURAL OBSERVATIONS OF A COLACIUM PALMELLA: THE RESERVOIR, EYESPOT, AND FLAGELLA1
Authors: Willey Ruth L. , Durban Elisa M. , Bowen William R. 
Published: August 2007

SUMMARYA recently described euglenoid of the genus Colacium inhabits the rectums of damselfly larvae during the winter as a nonflagellated, stalkless palmella stage. Contrary to previous reports, which were based on light microscope observations, ultrastructural observations establish that the reservoir and canal with its nonemergent flagella remain structurally intact in the palmella condition. The 2 non‐emergent flagella are structurally distinct. The larger flagellum, which probably gives rise to the single, emergent flagellant of the swimming euglenoid, has the typical 9 + 2 microtubular arrangement, together with a paraflagellar rod throughout most of its length. The crystalline paraflagellar body, typical of swimming euglenoids, is absent. The smaller flagellum has a 9 + 0 arrangement of the axonemal microtubules. This flagellum appears to terminate within the reservoir with a successive loss of number and arrangement of microtubules near its distal end. Hair‐like structures lining the reservoir membrane may represent preformed nontubular mastigonemes. The eyespot granules are clustered around the cytostome and do not display the compact organization or position typical of the flagellated stage or the stalked stage of Colacium.
“OBLIGATE” ALGAL EPIPHYTE: SMITHORA NAIADUM GROWS ON A SYNTHETIC SUBSTRATE1
Authors: Harlin Marilyn M. 
Published: August 2007

SUMMARYThe supposedly obligate epiphyte Smithora naiadum, normally found only on the sea grasses Phyllospadix scouleri and Zostera marina, grew on an artificial substrate under field conditions. This development shows that the alga does not appear to require a chemical factor from its normal host plant for (1) substrate selection and adhesion, (2) growth of basal cushion and young blades, or (3) maturation of thick cushions.
GLIDING MOTILITY OF OSCILLATORIA: ULTRASTRUCTURAL AND CHEMICAL CHARACTERIZATION OF THE FIBRILLAR LAYER1,2
Authors: Halfen Lawrence N. 
Published: August 2007

SUMMARYUltrastructural examination of platinum‐carbon replicated trichomes or wall fragments of 3 Oscilatoria species readily displayed the fibrillar components of the presumed motility system. These fibrils had a lateral organization as well as longitudinal continuity and wavelike distortions, which are consistent with the hypothesized movement mechanism. The fibrils were sensitive to proteolytic enzymes but resistant to hydrolytic agents, suggesting a protein composition. The fibrils and motility were unaffected by cytochalasin B.
ALGAL SUCCESSION ON ARTIFICIAL REEFS IN A MARINE LAGOON ENVIRONMENT IN GUAM1,2
Authors: Tsuda Roy T. , Kami Harry T. 
Published: August 2007

SUMMARYAlgal succession on artificial reefs constructed of tires has been studied over a 26‐mo period. Filamentous algae, ie, Calothrix crustacea, Feldmannia indica, and Sphacelaria tribuloides, are the primary colonizers; the fleshy brown alga, Dictyota bartayresii, appears soon after. Lobophora variegata is the only alga present which occurs seasonally. Low light penetration through the silly lagoon water and selective browsing by herbivorous fishes favor the blue‐greens Calothrix crustacea and Microcoleus lyngbyaceus to be the dominant algae in the climax community which, occurs within a 1‐year period.
SALINITY ADAPTATION BY DUNALIELLA TERTIOLECTA. I. INCREASES IN CARBONIC ANHYDRASE ACTIVITY AND EVIDENCE FOR A LIGHT‐DEPENDENT Na+/H+ EXCHANGE1,2
Authors: Latorella A. H. , Vadas R. L. 
Published: August 2007

SUMMARYWhen Dunaliella tertiolecta, previously adapted to medium containing 0.5 M NaCl, is transferred to higher salinities, there is a lag in growth, suggesting an adaptation period. Since there is no significant difference in the Na+ content of cells grown between 0.5 and 3.5 M NaCl, a mechanism for Na+ extrusion or exclusion is indicated.Increasing the salinity of cell suspensions stimulates an incorporation of H+ by the cells, suggesting an H+/Na+ exchange. Cells adapted to higher salinities have, increased carbonic anhydrase activity, suggesting that increased CO2 or HCO3− transport may be required at higher salinities.Growth, of D. tertiolecta at salinities above 2.5 M requires continuous illumination; therefore a light‐driven H+/Na+ exchange accompanied by a HCO3− influx is proposed.
ELECTROPHORETIC AND IMMUNOLOGICAL ANALYSES OF SEVEN CHLOROSARCINACEAN ALGAE1
Authors: Thomas Dempsey L. , Groover Robert D. 
Published: August 2007

SUMMARYProteins from 7 species of chlorosarcinacean algae representing 4 genera were studied with starch and disc gel electrophoresis and immunology to determine biochemical relationships. Migration patterns of enzymes and serological reactions indicated that 4 species of Chlorosarcinopsis were closely related, whereas Friedmannia israeliensis, Fasciculochloris boldii, and Chlorosarcina longispinosa were more diverse. Malate dehydrogenase, glutamate dehydrogenase, nonspecific alpha esterases, and peroxidase (using pyrogallol as the hydrogen donor) were present in all 7 species. No peroxidase activity occurred with benzidine. Leucine aminopeptidase was obvious in only 2 species. A single distinct band of general protein in F. israeliensis and C. longispinosa suggested the presence of homogenous reserve protein. The 7 species exhibited serological affinity to 4 isolates of Protosiphon representing diverse morphology within the genus. The data are discussed relative to current knowledge of comparative morphology of chlorosarcinacean algae.
SULFUR AND THE TOXICITY OF THE RED ALGA CERAMIUM RUBRUM TO BACILLUS SUBTILIS1,2
Authors: Ikawa Miyoshi , Thomas Victor M. , Buckley Lawrence J. , Uebel J. John 
Published: August 2007

SUMMARYCrystalline sulfur has been isolated from the red seaweed Ceramium rubrum and shown to be responsible for the toxicity of this alga to the growth of Bacillus subtilis. This alga was unusual in that it contained a much higher free sulfur content than other red and brown algae tested.
OBSERVATIONS ON THE SYMBIOSIS OF PERIDINIUM BALTICUM AND ITS INTRACELLULAR ALGA. I. ULTRASTRUCTURE1,2
Authors: Tomas Ronald N. , Cox Elenor R. 
Published: August 2007

SUMMARYThe ultrastructure of Peridinium balticum indicates that an eudosymbiont is present within the dinoflagellate. The structure and probable function of the organelles of both protists arc described and discussed. The origin of photosynthetic dinoflagellates from heterotrophic forms by means of a chrysophyte‐like endosymbiont is postulated.
PHYSIOLOGICAL ECOLOGY OF GELIDIELLA ACEROSA (FORSSKAL) FELDMANN ET HAMEL1
Authors: Rao P. Sreenivasa , Mehta V. B. 
Published: August 2007

SUMMARYThe effects of different concentrations of salinity, pH, and nutritional and growth‐promoting sub‐stances on the production of proliferations in Gelidiella acerosa were investigated, with a view of increasing the production rule of the alga in its aquiculture.
Comparing computed tomography localization with daily ultrasound during image‐guided radiation therapy for the treatment of prostate cancer: a prospective evaluation
Authors: Feigenberg Steven J. , Paskalev Kamen , McNeeley Shawn , Horwitz Eric M. , Konski Andre , Wang Lu , Ma Charlie , Pollack Alan 
Published: August 2007

In the present paper, we describe the results of a prospective trial that compared isocenter shifts produced by BAT Ultrasound (Nomos, Sewicky, PA) to those produced by a computed tomography (CT) unit in the treatment room to aid in positioning during image‐guided radiation therapy.The trial included 15 consecutive patients with localized prostate cancer. All patients underwent CT and MR simulation immobilized supine in an Alpha Cradle and were treated with intensity‐modulated radiation therapy. BAT Ultrasound was used daily to correct for interfraction motion by obtaining shift in the x, y, and z directions. Two days per week during therapy, CT scans blinded to the ultrasound shifts were obtained and recorded.We analyzed 218 alignments from the 15 patients and observed a high level of correlation between the CT and ultrasound isocenter shifts (correlation coefficients: 0.877 anterior–posterior, 0.842 lateral, and 0.831 superior–inferior). The systematic differences were less than 1 mm, and the random differences were approximately 2 mm. The average absolute differences, including both systemic and random differences, were less than 2 mm in all directions.The isocenter shifts generated by using a CT unit in the treatment room correlate highly with shifts produced by the BAT Ultrasound system.PACS numbers: 87.53, 87.59.fm, 87.63.Df
Image‐guided helical tomotherapy for localized prostate cancer: technique and initial clinical observations
Authors: Ramsey Chester R. , Scaperoth Daniel , Seibert Rebecca , Chase Daniel , Byrne Thomas , Mahan Stephen 
Published: August 2007

The purpose of the present study was to implement a technique for daily computed tomography (CT)–based image‐guided radiation therapy and to report observations on treatment planning, imaging, and delivery based on the first 2 years of clinical experience.Patients with previously untreated stage T1 – T3 biopsy‐proven adenocarcinoma of the prostate were considered eligible for treatment with daily CT‐guided helical tomotherapy. The prostate was targeted daily using megavoltage CT (MVCT) images that were fused with treatment‐planning CT images based on anatomic alignments. All patients were treated at 2 Gy per fraction to 76 – 78 Gy (mean: 76.7 Gy).As part of this study, 33 prostate patients were planned, imaged, and treated with a total of 1266 CT‐guided fractions. The prostate, rectum, bladder, femoral heads, and pubis symphysis were visible in one or more slices for all 1266 MVCT image sets. The typical range of measured prostate displacement relative to a 3‐point external laser setup in this study was 2 – 10 mm [3.4 mm standard deviation (SD)] in the anterior–posterior direction, 2 – 8 mm (3.7 mm SD) in the lateral direction, and 1 – 6 mm (2.4 mm SD) in the superior–inferior direction. The obese patients in this study had a substantially larger lateral variation (8.2 mm SD) attributable to mobility of skin marks. The prostate, seminal vesicles, rectum, and bladder anatomy were used to position the patient relative to the desired treatment position without the use of implanted markers. Acute toxicities were within the expected range given the number of patients treated and the dose level.PACS numbers: 87.50.Gi, 87.53.Mr, 87.53.Tf
Commissioning experience with cone‐beam computed tomography for image‐guided radiation therapy
Authors: Lehmann Joerg , Perks Julian , Semon Sheldon , Harse Rick , Purdy James A. 
Published: August 2007

This paper reports on the commissioning of an Elekta cone‐beam computed tomography (CT) system at one of the first U.S. sites to install a “regular,” off‐the‐shelf Elekta Synergy (Elekta, Stockholm, Sweden) accelerator system. We present the quality assurance (QA) procedure as a guide for other users. The commissioning had six elements: (1) system safety, (2) geometric accuracy (agreement of megavoltage and kilovoltage beam isocenters), (3) image quality, (4) registration and correction accuracy, (5) dose to patient and dosimetric stability, and (6) QA procedures. The system passed the safety tests, and agreement of the isocenters was found to be within 1 mm. Using a precisely moved skull phantom, the reconstruction and alignment algorithm was found to be accurate within 1 mm and 1 degree in each dimension. Of 12 measurement points spanning a ‐cm volume in a Rando phantom (The Phantom Laboratory, Salem, NY), the average agreement in the x, y, and z coordinates was 0.10 mm, mm, and 0.22 mm [standard deviations (SDs): 0.21 mm, 0.55 mm, 0.21 mm; largest deviations: 0.6 mm, 1.0 mm, 0.5 mm] respectively. The larger deviation for the y component can be partly attributed to the CT slice thickness of 1 mm in that direction. Dose to the patient depends on the machine settings and patient geometry. To monitor dose consistency, air kerma (output) and half‐value layer (beam quality) are measured for a typical clinical setting. Air kerma was 6.3 cGy (120 kVp, 40 mA, 40 ms per frame, 360‐degree scan, S20 field of view); half value layer was 7.1 mm aluminum (120 kV, 40 mA).We suggest performing items 1, 2, and 3 monthly, and 4 and 5 annually. In addition, we devised a daily QA procedure to verify agreement of the megavoltage and kilovoltage isocenters using a simple phantom containing three small steel balls. The frequency of all checks will be reevaluated based on data collected during about 1 year.PACS number: 87.53.Xd
Radiation shielding for gamma stereotactic radiosurgery units
Authors: McDermott Patrick N. 
Published: August 2007

Shielding calculations for gamma stereotactic radiosurgery units are complicated by the fact that the radiation is highly anisotropic. Shielding design for these devices is unique. Although manufacturers will answer questions about the data that they provide for shielding evaluation, they will not perform calculations for customers. More than 237 such units are now installed in centers worldwide. Centers installing a gamma radiosurgery unit find themselves in the position of having to either invent or reinvent a method for performing shielding design.This paper introduces a rigorous and conservative method for barrier design for gamma stereotactic radiosurgery treatment rooms. This method should be useful to centers planning either to install a new unit or to replace an existing unit. The method described here is consistent with the principles outlined in Report No. 151 from the U.S. National Council on Radiation Protection and Measurements. In as little as 1 hour, a simple electronic spreadsheet can be set up, which will provide radiation levels on planes parallel to the barriers and 0.3 m outside the barriers.PACS numbers: 87.53.Ly, 87.56By, 87.52Tr
Effect of skull shape approximations in Gamma Knife dose calculations
Authors: Berndt Anita , Beck James 
Published: August 2007

Doses in Leksell GammaPlan (Elekta, Stockholm, Sweden) are calculated for each shot by summing the contribution from the 201 radiation beams emitted by the Gamma Knife (Elekta), weighted for attenuation in the tissue traversed. The patient's head is modeled based on 24 skull measurements, from which the depth to the calculation point is determined for each beam. The limited number of measurement points associated with this approach can result in substantial discrepancies between the skull model used for dose calculations and the actual skull contour from computed tomography or magnetic resonance data. A review of 24 patients found that differences between the actual and approximated skull shape gave treatment time errors as large as 4.1%, although in most instances, the errors were less than 1%. The conclusion was that the Leksell GammaPlan head model provides a quick and convenient approach for specifying the shape of the patient's head in all but extreme cases, where discrepancies as large as ~5% can result.PACS number: 87.53.Ly
A survey on planar IMRT QA analysis
Authors: Nelms Benjamin E. , Simon Jeff A. 
Published: August 2007

Quality assurance (QA) systems for intensity‐modulated radiation therapy (IMRT) have become standard tools in modern clinical medical physics departments. However, because formalized industry standards or recommendations from professional societies have yet to be defined, methods of IMRT QA analysis vary from institution to institution. Understanding where matters stand today is an important step toward improving the effectiveness of IMRT QA and developing standards.We therefore conducted an IMRT QA survey. This particular survey was limited to users of an electronic two‐dimensional diode array device, but we took care to keep the questions as general and useful as possible. The online survey polled institutions (one survey per institution) on a collection of questions about methods of IMRT QA. The topics were general to the IMRT QA analysis methods common to all IMRT systems; none of the questions was vendor‐ or product‐specific.Survey results showed that a significant proportion of responding institutions (32.8%) use the single‐gantry‐angle composite method for IMRT QA analysis instead of field‐by‐field analysis. Most institutions perform absolute dose comparisons rather than relative dose comparisons, with the 3% criterion being used most often for the percentage difference analysis, and the 3 mm criterion for distance‐to‐agreement analysis. The most prevalent standard for acceptance testing is the combined 3% and 3 mm criteria. A significant percentage of responding institutions report not yet having standard benchmarks for acceptance testing—specifically, 26.6%, 35.3%, and 67.6% had not yet established standard acceptance criteria for prostate, head and neck, and breast IMRT respectively.This survey helps in understanding how institutions perform IMRT QA analysis today. This understanding will help to move institutions toward more standardized acceptance testing. But before standards are defined, it would be useful to connect the conventional planar QA analyses to their resulting impact on the overall plan, using clinically relevant metrics (such as estimated deviations in dose–volume histograms).PACS numbers: 87.50.Gi, 87.52.Df, 87.52.Px, 87.53.Dq, 87.53.Tf, 87.53.Kn, 87.56.Fc