Tape Station Research Articles

Ultra-short circulating tumor DNA (usctDNA): A new paradigm for ctDNA liquid biopsy.

e20510 Background: Mononucleosomal ctDNA (mnctDNA, 157-bp, double-stranded) spearheads liquid biopsy (LB) for cancer detection, treatment and clinical care. The bottleneck of mnctDNA LB are low copy number of ctDNA and limit of detection of platform technologies. Recent discovery of ultra-short ctDNA (usctDNA, 52-54 nt, single-stranded) that harbors somatic mutations prompted us to explore the quantification and stoichiometry of usctDNA to mnctDNA in plasma and saliva of NSCLC patients. Methods: Paired plasma and saliva from 20 advanced NSCLC patients with tissue genotyped positive for L858R were processed for cfDNA extraction and quantification with Qubit and Tape Station. Digital PCR assays targeting L858R somatic mutation to generate amplicons of 57-bp (usctDNA) and 100-bp (mnctDNA) were performed by UCLA and independently by NIST. Results: Results in Table 1 revealed that three findings of usctDNA that will have potential to impact ctDNA liquid biopsy. First, the somatic mutation (L858R) is present in usctDNA. Second, The stoichiometric ratio of usctDNA to mnctDNA is similar in plasma and saliva at 1.6X. For the wild-type counterpart, the ratio is 1.1X for plasma and 0.6X for saliva. Third, the copy number of usctDNA and mnctDNA in saliva to plasma is 7.8X and 7.7X. Conclusions: Detection of tumor-associated/specific EGFR L858R somatic mutations in uscfDNA is translationally impactful, adding 1.6X of the ctDNA targets for molecular detection, effectively cumulating 2.6X of total ctDNA targets, permitting earlier cancer detection, treatment monitoring and therapy prognostication. The finding that saliva harbors 7X of the us- and mnctDNA further raises the prospect of advancing saliva ctDNA liquid biopsy for NSCLC detection as it may effectively allow 15.5X (7.8X+7.7X) ability to detect malignancy-associated ctDNA. [Table: see text]

Abstract LB106: Ultra-short ctDNA: A new paradigm for ctDNA liquid biopsy

Abstract Mononucleosomal ctDNA (mnctDNA, 157-bp, double-stranded) spearheads liquid biopsy (LB) for cancer detection, treatment and clinical care. The bottleneck of mnctDNA LB are low copy number of ctDNA and limit of detection of platform technologies. Recent discovery of ultra-short ctDNA (usctDNA, 52-54 nt, single-stranded) that harbors somatic mutations prompted us to explore the quantification and stoichiometry of usctDNA to mnctDNA in plasma and saliva of NSCLC patients. Paired plasma and saliva from 20 advanced NSCLC patients with tissue genotyped positive for L858R were processed for cfDNA extraction and quantification with Qubit and Tape Station. Digital PCR assays targeting L858R somatic mutation to generate amplicons of 57-bp (usctDNA) and 100-bp (mnctDNA) were performed by UCLA and independently by NIST. Results in Table 1 revealed that three findings of usctDNA that will have potential to impact ctDNA liquid biopsy. First, the somatic mutation (L858R) is present in usctDNA. Second, The stoichiometric ratio of usctDNA to mnctDNA is similar in plasma and saliva at 1.6X. For the wild-type counterpart, the ratio is 1.1X for plasma and 0.6X for saliva. Third, the copy number of usctDNA and mnctDNA in saliva to plasma is 7.8X and 7.7X. Conclusion: Detection of tumor-associated/specific EGFR L858R somatic mutations in uscfDNA is translationally impactful, adding 1.6X of the ctDNA targets for molecular detection, effectively cumulating 2.6X of total ctDNA targets, permitting earlier cancer detection, treatment monitoring and therapy prognostication. The finding that saliva harbors 7X of the us- and mnctDNA further raises the prospect of advancing saliva ctDNA liquid biopsy for NSCLC detection as it may effectively allow 15.5X (7.8X+7.7X) ability to detect malignancy-associated ctDNA. Table 1. Quantification of usctDNA and mnctDNA in Plasma and Saliva Mut usctDNA (L858R) WT cfDNA usctDNA mnctDNA U/M uscfDNA mncfDNA U/M Plasma 1555 ± 326 964 ± 209 1.6X 15201 ± 1509 13261 ± 1424 Saliva 12158 ± 1731 7442 ± 1020 1.6X 340896 ± 27170 601733 ± 71573 1.1X Saliva/Plasma (fold X) 7.8 7.7 1.6X 22.4 45.3 0.6X Citation Format: Feng Li, Fang Wei, Hua-Jun He, Chien-Chung Lin, Szu-Chun Yang, Allen Wei-Lun Huang, Cheuk Ying Tang, Yong Kim, David T. Wong. Ultra-short ctDNA: A new paradigm for ctDNA liquid biopsy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB106.

P-098 Cryopreservation process deregulates the expression of pathways important for fertility in human spermatozoa

Abstract Study question Does cryopreservation impact on transcriptome of conventional frozen human spermatozoa? Summary answer The cryopreservation of human sperm alters pathways important for fertility, although the upregulation of some genes can compensate for the harmful effects of freezing. What is known already Sperm cryopreservation is a widely used procedure for storing gametes for later use, for preserving fertility in patients before gonadotoxic treatments or surgery, and for sperm donation programs. The cryopreservation technique can cause damage to sperm through induction of DNA alterations, fragmentation and oxidation, and altered motility, mitochondrial activity and morphology. Transcriptomic alterations have been reported in cryopreserved sperm from various animal species, but no experimental data are available on the effect of cryopreservation on the transcriptome-wide profile of human sperm. Study design, size, duration Semen samples were obtained from 20 normospermic men from April to May 2022. Each sample was divided in two aliquots. From one aliquot total RNA was immediately extracted. The second aliquot was slowly cryopreserved and after a week of storage in liquid nitrogen total RNA was extracted. A total of 13 paired RNA samples passed quality control and were analyzed after randomization into 4 pools, each of 6 patients. Participants/materials, setting, methods The men who participated in this study had a median age of 35.0 years (range: 29.0-46.0). RNA was extracted by miRNeasy Micro Kit (Qiagen), analyzed by High Sensitivity RNA on 2200 Tape Station system (Agilent), amplified by Ovation Pico WTA SystemV2 (Nugen), labeled and hybridized on GE 4x44K v2 microarrays (Agilent). The paired Significance Analysis of Microarray (SAM) was performed using the limma hgug4112a.db and samr packages in R/BioConductor. Main results and the role of chance The expression profiles of cryopreserved sperm significantly differed from those of fresh sperm in 219 down-regulated and 28 up-regulated unique transcripts. The gene ontology analysis disclosed that cryopreservation downregulates genes involved in sperm motility by the mitochondria function (CABS1, SPATA19) and the correct organization of the sperm midpiece and flagellum cytoskeleton (ACTL7A, AKAP4, C9ORF24, CAPZB, CCIN, IQCG, ODF2, SPATA6, SPATA6L, TBC1D21), in fertilization (ACTL7A, AKAP4, PLCZ1, PRSS37, TUBGCP3), early embryo development (AGT, CLMN, DCC, DHRS3, EGFLAM, FAM20A, FREM1, GPI, HEMGN, KRTDAP, IFT172, MICAL2, MLF1, NF2, PGRMC2, PHACTR1, POPDC3, RO60, ROBO1, RORA, SGCA, SPRR2D, TCF4, TNC, TNNI3), oxidant detoxification (TXNDC29) and DNA repair (BRIP1, ERCC6, TRIP12), calcium ion binding and homeostasis (AMY1C, ANO1, ANO2, ASGR1, CABS1, CPNE9, FREM1, KCNIP2, ITPR3, PKD2L1, PLCZ1, SELENOK, SYN3, TNNI3). Upregulated genes were enriched in pathways related to the negative regulation of DNA damage response (ALOX15B, CD74, RPL10, SNAI1, THBS1), cellular response to calcium ion (ALOX15B, FOSB, HLA-DQB1, S100A4, THBS1), regulation of transcription (CD74, FOSB, HLA-DRB1, MAMLD1, RASD1, RPL10, SNAI1, TCF15, TLE1), protein stabilization (CD74), protein ubiquitination (BAG1, DCAF6, ERCC6, HERPUD2, KLHL7, MARCHF8, NF2, PSMA6, RNF133, SERGEF, TRIP12, UBE2DNL, UBL3, UBQLN3, ZNRF3) and ubiquitin protein ligase binding (GPI, HSPA1L, PRKAR2A, STX8). Limitations, reasons for caution Data validation in a larger sample cohort and by quantitative PCR would be useful, although we have applied stringent criteria for gene selection (FDR = 0). Further research should be undertaken to experimentally test whether the length of cryostorage can have any effect on the gene expression profile of sperm. Wider implications of the findings Specific pathways are deregulated by cryopreservation, in accordance with altered sperm morphology, motility and molecular integrity reported in literature. Functional enrichment analyses also revealed gene expression changes to compensate for the sperm cryoinjury. This finding is noteworthy for safety issue of sperm banking i.e., fertility preservation, gamete donation. Trial registration number not applicable

Assessment of the viability and quality of equine endometrial explants as a potential ex vivo model for fibrosis research

There is a lack of experimental models to study endometrosis ex vivo. We evaluated viability, RNA integrity, gene and protein expression of genes relevant to fibrosis in an ex vivo model with mare endometrial explants. Uteri from healthy mares were collected during the reproductive season at an abattoir, and transported on ice to the laboratory. Uteri without signs of inflammation or contamination and an active ovary were processed: endometrial biopsies (∼50mg) were collected, washed (Hanks balanced salt solution + 0.1% BSA and 3xAAM), placed in 24-well plates (1 mL) and pre-incubated in DMEM with the same additives at 37°C, 5%CO2 for 1h. Thereafter, medium was replaced and explants cultured for 0, 24, 48, 72 or 96h. At these time points, viability was assessed using Alamar blue staining, RNA and proteins were extracted using Trizol. RNA integrity and quantity were assessed using RIN measurement (Tape Station Bioanalyzer; Agilent, USA). Proteins were quantified by Kit Pierce™ BCA Protein Assay (Thermo, USA) and visualized in SDS-PAGE (10% polyacrylamide). Statistical differences for viability assays were performed by ANOVA (P<0.05 cutoff). Culturing explants for 24 or 48h did not affect their viability compared to T0, but viability dropped after 72 and 96h (p˂ 0.05). Non-viable explants were used as reference, and time zero was set aspositive control. RNA integrity declined with prolonged culture of explants, RIN values at 96h were 4 to 6, indicative of RNA degradation. Relative expression of candidate genes involved in fibrosis and apoptosis by RT-PCR demonstrated a steady decrease in the expression of αSMA, PTGES, COL1A1 and COL3A1 transcripts at all time points compared to T0 (p<0.05). Conversely, expression of pro-apoptotic gene BAX increased (p<0.05) when explants were culture for 48h and further. We did not study any particular protein, but the overall yield (Pierce assay) and quality of proteins (SDS-PAGE) in the explants also dropped alongside with increased culture, being more evident after 48h. In conclusion, endometrial explants can be cultured in vitro for up to 48h without noticeable decrease of viability, RNA and protein yield and integrity, and with measurable expression of candidate genes. Prolonging culture for longer than 48h negatively affected viability and quality of the explants. The window of time of 48h of culture of endometrial explants could allow for the evaluation of potential anti-fibrotic drugs or treatments for mare endometrosis. Funded by FONDECYT REGULAR 1210349, ANID, Government of Chile.

The CERN-ISOLDE fast tape station

The employment of a suitable radioactive decay spectroscopy setup is essential for the operation of radioactive ion beam (RIB) facilities. CERN-ISOLDE recently developed a new fast tape station (FTS) setup to replace its more than 40 years old predecessor. The new FTS is equipped with several β-detectors, a HPGe-detector, provisions for an α-detector, and constitutes a significant improvement in terms of transport times and detector noise characteristics. Since 2021 it is routinely used as the primary asset for yield determination and quality control of produced RIBs at ISOLDE. We address in this work its technical features and introduce the utilized control system.

A Standardized Protocol for Donor-Derived Cell-Free DNA Quantification in the Diagnosis of Allograft Injury

Purpose There is an increasing interest in the use of donor-derived cfDNA (dd-cfDNA) in transplantation for non-invasive diagnosis of allograft injury. We hereby describe a non-commercial routine procedure for dd-cfDNA detection and quantification using digital droplet PCR and target-specific preamplification of a SNP-panel of 35 SNP-assays. The method is based on the difference in genotype between recipients and donors. After establishing our protocol, it has been used in a prospective study following recipients for 12 months after heart transplantation (HTx), and we here briefly describe our protocol. Methods A total of 728 samples from 67 HTx patients have been retrieved and analyzed. The recipients were genotyped preoperatively with respect to the SNP-panel. Upon transplantation, the donor genotype was interrogated with respect to the homozygous alleles found in the recipient. After HTx, blood samples were collected in cell free DNA collection tubes and delivered within the same day to the hospital laboratory. Plasma was separated by centrifugation at 2000g and 16000g, respectively. Isolated plasma was stored at -80C or used immediately for cfDNA extraction. Quality controls were performed by the 4200 Tape Station. The same primers were used for preamplification and downstream PCR. Non-template controls were included in all preamplification steps. The amount of dd-cfDNA was calculated as a fraction of the total cfDNA. Results The variation of extracted cfDNA yield was 10-130 ng/ml plasma. The 50-800 bp sized cfDNA constitutes 90% of the extracted samples, indicating a low background. An average of 2-5 informative SNPS assays for each transplant recipient were used for dd-cfDNA quantification with a detection rate down to 0.01% dd-cfDNA. Elevation of dd-cfDNA was seen not only in conjunction with cellular rejection but also during infection and in episodes of heart failure Conclusion Samples from HTx recipients demonstrated low levels of dd-cfDNA in consecutive samples during optimal treatment in non-eventful cases. Elevation of dd-cfDNA was seen not only during rejection but also in other conditions. This non-invasive method is relatively cheap, enables large sample yields by preamplification, has a fast turn-around time (48 hours) and is thus useful for clinical monitoring of HTx patients. However, it needs to be carefully related to clinical events.

Phylogenetic Analysis of Candida auris Isolates From Clinical Samples of Surgical Intensive Care Units

Background: Between January and September of 2019, 15 patients acquired Candida auris infection in our surgical intensive care unit (SICU). Although the outbreak was controlled by enhancing horizontal measures and a change of the environmental disinfectant from a quaternary ammonium compound to a peroxide-based product; we wanted to understand whether patient-to-patient spread was occurring or the environment was the major contributor. Methods: We submitted all the 15 isolates from clinical samples for WGS and phylogenetic analysis; along with operation theater (OT) and ICU environment random swabs for metagenomic analysis. DNA sample QC DNA extraction was done using a Qiagen QiAmp DNA mini kit (cat. no. 51306). The DNA samples were subjected to QIAXPERT and Qubit for quantifying the amount of DNA in the extracted sample. Also, the 260/280-nm ratio was examined for the purity of the same. They were also subjected for agarose gel electrophoresis. For the DNA library prep protocol, whole-genome libraries were prepared from 21 samples using NEBNext Ultra IITM DNA Library Prep Kit (Cat. No: E7645L). The adapter sequences were added to the ends of DNA fragments to generate paired-end libraries. The resulting adaptor-ligated libraries were purified and index tags were added by amplification, followed by purification. Libraries were assessed to check the quality and quantity using Agilent 2200 Tape station (cat. no. 3-PM 863NA). For the sequencing protocol, prepared libraries were quantified using Qubit High Sensitivity reagent. The obtained libraries were diluted to final concentration of 2 nm in 10 µL and were subjected to cluster amplification. Once the cluster generation was completed, the flow cells were loaded on to the sequencer. Sequencing was carried out in Hi Seq X10 to generate 2X150-bp sequence reads at &gt;100X sequencing depth (~1.5 Gb). A minimum of 75% of the sequenced bases were of Q30 value. Sequenced data were processed to generate FASTQ files and were uploaded on the FTP server for download and secondary data analysis. Results: Overall, 2% of the DNA from the OT and SICU environment showed Candida auris. The phylogenetic analysis confirmed 2 different clusters. Furthermore, 13 of the clinical isolates belonged to the same cluster, confirming that patient-to-patient transmission had occurred, which was subsequently confirmed by line listing the patients. Conclusions:Candida auris can efficiently spread from patient to patient, resulting in outbreaks. It can also persist in the healthcare environment causing ongoing propagation of these outbreaks.Funding: NoneDisclosures: None

A multiplex PCR strategy to screen for known mutations in families with sudden cardiac death burden.

Ventricular tachyarrythmia occurring in ischemic heart disease, dilated/hypertrophic cardiomyopathies or rare monogenic mutations of cardiac ion channels or associated proteins belong to the most frequent causes of sudden cardiac death (SCD). In further decades, next generation sequencing and bioinformatic analysis will become the gold standard of SCD risk stratification. At the moment, Sanger-sequencing is still obligatory in genetic diagnosis. A multiplex polymerase chain reaction (PCR) assay detecting eight SCD mutations in one reaction-tube was developed. To test the general validity of the assay, it was used with 12 patients, who had one or two of the eight mutations (LMNA, p.V256V; SCN5A, p.R1583C; RYR2, p.G1885E; MYH7, V606M; DSG2, p.T335A; KCNJ8, p.S422L; MYBPC, p.E441K; TNNT2, A38V). Thereafter, we tested the multiplex assay in a real diagnostic environment within a high risk family of several past SCD cases. This method allows efficient discrimination of multiple mutations by allele-specific PCR with standard PCR conditions. It relies on obtaining a PCR product specific to the mutation or wildtype—using primers that have the 3′end base complementary to the DNA template site, i.e. a specific primer only permits amplification to take place when its 3′terminal nucleotide matches with its target sequence. The PCR products are further analyzed by length, with Tape Station®(Agilent Technologies, Germany), a high-fidelity capillary chromatography test. The novel multiplex PCR assay strategy could be a good additional test used for SCD risk stratification. Advantages of the test are high velocity and ease of implementation, low price and flexibility of application within cardiomyopathy families for screening purposes.

Low-lying intruder and tensor-driven structures inAs82revealed byβdecay at a new movable-tape-based experimental setup

The $\ensuremath{\beta}$ decay of $^{82}\mathrm{Ge}$ was re-investigated using the newly commissioned tape station BEDO at the electron-driven ISOL (isotope separation on line) facility ALTO operated by the Institut de Physique Nucl\'eaire, Orsay. The original motivation of this work was focused on the sudden occurrence in the light $N=49$ odd-odd isotonic chain of a large number of $J\ensuremath{\le}1$ states (positive or negative parity) in $^{80}\mathrm{Ga}$ by providing a reliable intermediate example, viz., $^{82}\mathrm{As}$. The extension of the $^{82}\mathrm{As}$ level scheme towards higher energies from the present work has revealed three potential ${1}^{+}$ states above the already known one at 1092 keV. In addition our data allow ruling out the hypothesis that the 843 keV level could be a ${1}^{+}$ state. A detailed analysis of the level scheme using both an empirical core-particle coupling model and a fully microscopic treatment within a Skyrme-QRPA (quasiparticle random-phase approximation) approach using the finite-rank separable approximation was performed. From this analysis two conclusions can be drawn: (i) the presence of a large number of low-lying low-spin negative parity states is due to intruder states stemming from above the $N=50$ shell closure, and (ii) the sudden increase, from $^{82}\mathrm{As}$ to $^{80}\mathrm{Ga}$, of the number of low-lying ${1}^{+}$ states and the corresponding Gamow-Teller fragmentation are naturally reproduced by the inclusion of tensor correlations and couplings to 2p-2h excitations.

CARIBU: a new facility for the study of neutron-rich isotopes

The Californium Rare Ion Breeder Upgrade (CARIBU) to the ATLAS superconducting linac facility is currently being commissioned. It provides low-energy and re-accelerated beams of neutron-rich isotopes obtained from 252Cf fission. The fission products from a 252Cf source are stopped in a large high-intensity gas catcher, thermalized and extracted through an RFQ cooler, accelerated to 50 kV and mass separated in a high-resolution separator before being sent to either an ECR charge breeder for post-acceleration through the ATLAS linac or to a low-energy experimental area. This approach gives access to beams of very neutron-rich isotopes, many of which have not been available at low or Coulomb barrier energies previously. These beams provide unique opportunities for measurements along the r-process path. To take advantage of these unique possibility, the reaccelerated beams from CARIBU will be made available at the experimental stations of ATLAS to serve equipment such as Gammasphere, HELIOS and the reaction spectrometers. In addition, the Canadian Penning Trap (CPT) mass spectrometer has been moved to the CARIBU low-energy experimental area and a new injection line has been built. The new injection line consists of a RFQ buncher sitting on a 50 kV high-voltage platform that will accumulate the mass separated 50 kV radioactive beams, cool and extract them as a pulsed beam of 3 keV. This beam can be sent either to a tape station for diagnostics and tuning, or a cryogenic linear trap for preparation before transfer to the high-precision Penning trap where the mass measurements will take place. Initial CARIBU commissioning is proceeding with a 2 mCi source that will be replaced by a 100 mCi source as the commissioning proceeds. Final operation will use a 1 Ci source and attain yield in excess of 107 ions/sec for the most intense beams at low energy, an order of magnitude less for reaccelerated beams.

STRUCTURE OF THE NEUTRON RICH Ga AND Ge ISOTOPES OBSERVED AT ALTO

During test runs dedicated to the commissioning of ALTO (Accélérateur Linéaire et Tandem à Orsay), β and β- n decay of the very neutron rich [Formula: see text] could be observed at the tape station installed on-line with the PARRNe mass-separator. γ-lines observed in the resulting spectra and a careful analysis of the balance of their relative intensities point toward the existence of two β-decaying states in 84 Ga . The decay of these long-lived states appear to feed the [Formula: see text] and [Formula: see text] excited states of [Formula: see text] and the [Formula: see text] state in [Formula: see text] allowing a significant improvement of the knowledge on nuclear structure in the immediate vicinity of 78 Ni .

Management of ISOLDE yields

Isotope yields at ISOLDE are regularly measured online (with dedicated gamma and beta detectors) and off line by implantation and subsequent alpha-, beta- or gamma spectroscopy. The Java based measurement software, dedicated to tape station measurements, has been updated in order to automate yield measurements and provide possibilities to repeat existing measurements. A procedure supported by dedicated programs was established to analyze data. The results are centrally stored and provide an interface to the existing ISOLDE yield database. The present ISOLDE yield database has been recently created and updated with a large number of yields compiled from published data. The database developed on ORACLE guarantees reliability and security and provides a simple way of compiling new information. A user oriented interface has been programmed allowing accessing the information via a web browser. Several levels in the database structure provide selective access to different layers of technical information for advanced users and for technical R&D. The improvements in the yield measurement procedure, the data storage and accessibility, as well as the new database structure, the web application and the access interfaces, enhance the communication between technical information like yields and the users of the ISOLDE facility.

Evaluation for magnetic tape surface on characteristics of tape-run.

In a few cases, we have had troubles with magnetic tape stations, such as unusual tape movement. After research on this problem, we have found a cause for these accidents.We found the existence of sticky materials of molecular weight (several ten thousands) in the tape was the potential factor. The factor can be assessed by running the extract of tape by Freon TMC® through a gell permeation chromatograph.In practice the trouble occurs combining it with the factors of equipment and environment. Thus, we developed what we call a “Press Binding Test”, employing these constant factors, as a good evaluation method to assess the surface of the magnetic tapes.Although only a small fraction of the magnetic tapes passed this test about 10 years ago, almost all of the recent new computer tapes have pass this test.

Interface magnetic tape station to Camac for on-line data acquisition and reduction system

A magnetic tape station (Kennedy 8107/8230) interface to a Camac dataway is described. It allows writing and reading data and also searching tape in forward and reverse directions under total computer control. The complete logic diagram and its description are presented.

A Lithospheric Seismic Profile in Britain--I Preliminary Results

Summary The planning, execution and preliminary results of a major Anglo-German explosion seismic project are presented in this, paper I of a series. This Lithospheric Seismic Profile in Britain (LISPB) was planned as a reversed 1000 km line between two major sea-shot points off Cape Wrath in Scotland and one in the English Channel; additional sea-shots and intermediate land-shots were fired to give reversed and overlapping crustal coverage (to 180–400 km distance) along the line. In all, 29 shots were fired and 60 mobile magnetic tape stations recorded three-components of ground‘motion. The resulting 14 crustal and three long-range profiles have observations at intervals of typically 2–4 km. Recordings have been digitized and four examples of filtered, computer-plotted record sections are presented to illustrate data quality. In a preliminary analysis, phase correlations are discussed and some models presented; the latter especially are more relevant to future interpretations than to geological or tectonic problems. However, significant variations in crustal thickness and in the nature of the crust-mantle transition do seem to occur beneath the British Isles.

Computer Control of the Halden Boiling Water Reactor Part I: Plant Supervision Function and Corresponding On-Line Software System

At the OECD Halden Reactor Project, Halden, Norway, an international research and development programme on computer control of nuclear power reactors is being conducted. The programme aims for demonstration of plant supervision functions, direct digital control using conventional and advanced methods, and schemes for optimal control of the core power distribution. These functions are implemented on IBM-1800 and NORD-l process control computers with about 750 analogue inputs and 200 digital inputs and outputs, disk and tape stations, displays and operator console. The multitude and complexity of computer functions have required the design of an extensive user-oriented software system to obtain efficient data flow and computer utilization, and to serve as basis for proper operator-process communication functions. The computer system has been ope rational for on-line applications since 1967 and in routine operation for supervision, data logging and direct digital control, whereas advanced control methods have been tried on the reactor in separate experiments.The present paper describes the plant supervision system comprising monitoring of plant variables, alarm handling and operators communication, and includes some of the operational experience obtained.

Case Study of Operator Communication and Planned Development in Connection with Computer Control of the Halden Boiling Water Reactor

Process computers are increasingly being used for control and supervision of nuclear power reactors as the reactor control become s more complex due to increased plant size and load requirements from the grid. In addition, the operating characteristics are such that one is getting closer to the technical limits of the system. As a consequence, the extended use of computers implies that more emphasis is put on operator-proces s communication.At the OECD Halden Reactor Project, the reactor being an experimental power reactor, an international research and development programme on computer control of nuclear power reactors is being conducted. The programme aims for demonstration and routine operation of plant supervision as well as direct digital control using conventional and advanced methods. For experiments and routine operation the operator communication system is one of the main components in the system. This computer based system is operating in parallel with and is supplementing a conventional control system.The control desk consists of a console, alphanumeric and graphic Cathode Ray Tube display units (CR Ts) journal and report typewriters and plotter. The function of the console is to enable the operators to display process variables, request status, enter constants, change limits, and start and stop control routines. The CR Ts are used for prewarnings and alarm handling, messages, trend and status display, etc.The functions are implemented on a process control computer with about 750 analogue inputs and 224 digital inputs and outputs, 11 analogue outputs, 3 disk drives, 2 tape stations, and a line printer. The computer system has been operational for online applications since the end of 1967, and the scope of computer applications together with the communication system have gradually been extended.The multitude and complexity of computer functions have required a design of an extensive user-developed software to obtain an efficient dataflow and to serve as basis for proper operator - process communication functions. In designing and programming the communication system, emphasis has been put on obtaining sufficiently short response time, clear language with respect to text formats, organization of output, etc. Some efforts have been made to apply human engineering with the purpose of avoiding operator maloperations.The control desk has been easily understood and accepted by the operators, but not all functions introduced were equally much appreciated.Based on this experience which has been followed up by ergonomic studies, further investigations on man - computer - process communication systems will be conducted. This is envisaged due to thedevelopment of new hardware, like advanced minicomputers, and extended use of colour displays. A general purpose communication system, based on modules which can be configurated for the particular purposes can now be realized. The communication system could possibly be adapted to any general process computer. The development of a standard operator communication language is proposed.The paper deals with the experience obtained and the further development plans.

Efficiency of the polyphase merge and a related method

A sorting technique known as the polyphase merge is described. The notationE n (p) is introduced for the effective power of the merge. It is defined for the maximal file that can be sorted withinn passes withp+1 available magnetic tape stations. Then the valueE(p)=limn→∞E n (p) is evaluated as a function ofp. UsingE(p) as a measure of efficiency the author discusses the polyphase merge comparing it with a merge technique which is essentially a combination of the polyphase and the balanced merge. To the author's knowledge this technique is new.

The BIZMAC II Tapefile

THE BIZMAC system was initially designed to meet the requirements of large integrated clerical operations. This was accomplished by analyzing the operations in public utilities, life-insurance companies, government agencies, merchandising and manufacturing firms. As a result of these studies, the BIZMAC I system was designed. Three BIZMAC I systems, with a total number of more than 200 tape stations, are now in service.