Exposure assessment for retrospective follow-up studies of semiconductor- and storage device-manufacturing workers

OBJECTIVE

This exposure assessment was conducted in the first large study of mortality and cancer incidence in semiconductor and storage device manufacturing.

METHODS

Unique combinations of division, department and job codes and names (DDJ) from work history records were assigned to work groups and exposure categories. Agent exposure matrices assessed differences in potential exposures between groups. Changes in exposure over time were tracked by dividing the production history into manufacturing eras.

RESULTS

Nineteen work groups were developed to capture 310,351 unique DDJs from 1965-1999. Agent exposure matrices contrasted exposure potential to solvents, metals, and work in cleanrooms between groups, and three manufacturing eras were identified for each site.

CONCLUSIONS

The work groups, manufacturing eras and agent matrices have been used to classify workers in the study of cancer incidence and mortality.

Single-ion dosemeter based on floating gate memories

Floating Gate (FG) nonvolatile memories are based on a tiny polysilicon layer (the FG) which can be permanently charged with electrons or holes, thus changing the threshold voltage of a MOSFET. Every time a FG is hit by a high energy ion, it experiences a charge loss, depending on the ion linear energy transfer (LET) and on the transistor geometrical and electrical characteristics. This paper discusses the opportunities to use this devices as single an ion dosemeter with sub-micrometer spatial resolution and capable of distinguish the impinging ion LET.

An autonomous, broadband, multi-channel neural recording system for freely behaving primates

Successful laboratory proof-of-concept experiments with neural prosthetic systems motivate continued algorithm and hardware development. For these efforts to move beyond traditional fixed laboratory setups, new tools are needed to enable broadband, multi-channel, long duration neural recording from freely behaving primates. In this paper we present a dual-channel, battery powered, neural recording system with integrated 3-axis accelerometer for use with chronically implanted electrode arrays. The recording system, called HermesB, is self-contained, autonomous, programmable and capable of recording broadband neural and head acceleration data to a removable compact flash card for up to 48 hours.

Metal-free silicon-molecule-nanotube testbed and memory device

Work from several laboratories has shown that metal nanofilaments cause problems in some molecular electronics testbeds. A new testbed for exploring the electrical properties of single molecules has been developed to eliminate the possibility of metal nanofilament formation and to ensure that molecular effects are measured. This metal-free system uses single-crystal silicon and single-walled carbon nanotubes as electrodes for the molecular monolayer. A direct Si-arylcarbon grafting method is used. Use of this structure with pi-conjugated organic molecules resulted in a hysteresis loop with current-voltage measurements that are useful for an electronic memory device. The memory is non-volatile for more than 3 days, non-destructive for more than 1,000 reading operations and capable of more than 1,000 write-erase cycles before device breakdown. Devices without pi-conjugated molecules (Si-H surface only) or with long-chain alkyl-bearing molecules produced no hysteresis, indicating that the observed memory effect is molecularly relevant.

Portable technology device designed to manage childhood diabetes

MyDOK (Diabetes Organizer Key), a type 1 diabetes management tool, was designed to be a comprehensive personal health system used to monitor, control and coordinate treatment for children with diabetes. The development of this mobile data storage device (MDSD) for organizing and sharing social, behavioral, and clinical information is an important innovation because it empowers patients and their families to be a significant stakeholder in their medical care.

Digital video recording and archiving in ophthalmic surgery

Currently most ophthalmic operating rooms are equipped with an analog video recording system [analog Charge Couple Device camera for video grabbing and a Video Cassette Recorder for recording)]. We discuss the various advantages of a digital video capture device, its archiving capabilities and our experience during the transition from analog to digital video recording and archiving. The basic terminology and concepts related to analog and digital video, along with the choice of hardware, software and formats for archiving are discussed.

A cross-sectional international survey of continuous subcutaneous insulin infusion in 377 children and adolescents with type 1 diabetes mellitus from 10 countries

OBJECTIVE

To document current practices using continuous subcutaneous insulin infusion (CSII) by downloading electronically the 90-d pump data held within the pump memory and relating that to clinical data from children and adolescents in different pediatric diabetes centers from Europe and Israel.

METHODS

Data of patients (1-18 yr) treated with CSII in 23 centers from nine European countries and Israel were recorded with the encapture software (PEC International, Frankfurt, Germany). The number of patients who participated was 377 (48% female; mean diabetes duration +/- SD: 6.8 +/- 3.7 yr; age: 12.9 +/- 3.8 yr, preschool n = 33; prepubertal n = 95; adolescent n = 249; CSII duration: 1.6 +/- 1.2 yr; local HbA1c: 8.1 +/- 1.2%).

RESULTS

The total insulin dose was lower than previously reported for injection therapy (0.79 +/- 0.20 U/kg/d). Covariance coefficient of daily total insulin was high in all age groups (adolescents 19 +/- 9%, prepubertal 18 +/- 8 and preschool 17 +/- 8). The distribution of basal insulin infusion rates over 24 hr (48 +/- 12% of total dose) varied significantly between centers and age groups. The number of boluses per day (7 +/- 3) was not significantly different between the age groups (average daily bolus amount: 0.42 +/- 0.16 U/kg). The rate of severe hypoglycemia (coma/convulsions) was 12.4 episodes per 100 patient-years and the number of diabetes-related hospital days was 124 per 100 patient-years.

DISCUSSION

Pediatric CSII patients show a high variability in their insulin therapy. This relates both to age-dependent differences in the distribution of basal insulin as to the age-independent day-to-day variation in prandial insulin.

Mortality Among Semiconductor and Storage Device-Manufacturing Workers

PROBLEM

We evaluated mortality during 1965 to 1999 among 126,836 workers at two semiconductor facilities and one storage device facility.

METHOD

We compared employees' cause-specific mortality rates with general population rates and examined mortality patterns by facility, duration of employment, time since first employment, and work activity.

RESULTS

Employees had lower-than-expected mortality overall (6579 observed deaths, standardized mortality ratio [SMR] = 65; 95% confidence interval [CI] = 64-67), for all cancers combined (2159 observed, SMR = 78, 95% CI = 75-81) and for other major diseases. Central nervous system cancer was associated with process equipment maintenance at one of the semiconductor facilities (10 observed, SMR = 247, 95% CI = 118-454). Prostate cancer was associated with facilities/laboratories at the storage device facility (18 observed, SMR = 198, (5% CI = 117-313).

CONCLUSIONS

Further evaluation of workplace exposures or independent investigations of similar occupational groups may clarify the interpretation of associations observed in this study.

Digitizing stereoscopic optic nerve head photographs for storage and viewing using a personal computer

Careful examination and monitoring of optic nerve head changes is essential in the treatment of patients with glaucoma. This often results in accumulation of numerous photographs and required appropriate storage space. A simple, inexpensive, and efficient means of storing and viewing stereoscopic optic nerve head photographs is described. Images were acquired with a fundus camera, on a color slide film. Slides were then scanned and digitized. A handheld stereoscope was used for stereoscopic viewing on a computer monitor. A scanning resolution of 300 dpi appeared optimal. At this resolution, the storage utilization was 16 kilobytes and the scanning time was 160 seconds per patient.

Surface bio-magnetism on bacterial cells adhesion and surface proteins secretion

Extensive research works have been done on using magnetic fields on biological organism, but the results till date have been controversial [D.O. Carpenter, S. Ayrapetyan (Eds.), Biological Effects of Electric and Magnetic Fields, vol. 1, Academic Press, San Diego, 1994]. In spite of this, the study of surface magnetic effects on bacterial adhesion and cell growth has not been rigorously explored. The effects of surface magnetism, using perpendicularly polarized magnetic media, are evaluated on Bacillus licheniformis, a widely used bacterium in brewery [L. Kandra, a-Amylases of medical and industrial importance. J. Mol. Struct. (Theochem.), in press] and pharmaceutical [H. Ikram-ul et al., Production of alph amylase by Bacillus licheniformis using an economical medium. Bioresour. Technol. 87 (2003) 57-61] industries, by observing its adhesion and growth behavior. At different spin directions, we are able to observe a change on the biofilm formation, protein synthesis, and cell growth rate. Given that surface energy can easily penetrate through cells, this approach is an advantage over existing techniques that require direct physical contact to target cells. It also presents a new technique to cell adhesion and synthesis of surface proteins.

Potential for enlarging DNA memory: the validity of experimental operations of scaled-up nested primer molecular memory

DNA is an attractive memory unit because of its immense information density. Here, we describe a memory model made of DNA, called Nested Primer Molecular Memory (NPMM). NPMM consists of many DNA strands, and each DNA strand consists of two areas: a data area and a data address area. When the address of target data is specified, only the target data can be extracted from NPMM. In this paper, we evaluate the validity of the basic operations of NPMM and then discuss the feasibility of scaled-up NPMM through some laboratory experiments. In the latter, we deal with scaled-up NPMM simulated by the Concentration Scaling method.

Radiation risk and cost-benefit analysis of a paediatric radiology procedure: results from a national study

A national study was performed to investigate radiation doses and associated risks to patients during X-ray fluoroscopy-guided small intestinal biopsies in the investigation of coeliac disease. Thermoluminescent dosemeters (TLD) and questionnaires were sent to 42 of the 43 paediatric departments in Sweden performing these biopsies. During the study period (2 x 3 weeks) 257 biopsies were recorded, representing about 10% of annually performed paediatric investigations. The results show that the absorbed dose during biopsy ranged from 0.04 mGy to 23.8 mGy (mean 1.87 mGy). The fluoroscopy time ranged from 2 s to 663 s (mean 60 s). The collective dose from the procedure amounts to 4.7 manSv year(-1). Thus, the annual excess cancer mortality, including severe hereditary effects, can be estimated at 0.6-0.7 cases per year. However, significant dose saving can be obtained by proper choice of sedation and biopsy equipment.

[Building a SAN and NAS integrated storage system in hospitals]

We have recentely built a cluster and backup system based on a SAN + NAS integrated storage system at a low price. The integration of SAN + NAS provides a storage system of fine quality, high reliability and high stability for hospitals. The article mainly introduces the choice of the project, the design of SAN + NAS integration and its implementation.

On the use of DICOM cine header information for optimisation: results from the 2002 European DIMOND cardiology survey

The paper explores the level of information contained within the DICOM header in images from various cardiology systems. Data were obtained in the European DIMOND survey on image quality (Italy, Ireland, Belgium, Greece and Spain). Images from five standard diagnostic cardiology procedures carried out in six European hospitals have been analysed. DICOM header information was extracted to a database in order to analyse how it could help in the optimisation of the procedures. The level of data contained in the headers differs widely between cardiology systems. None of the X-ray systems in the 2002 survey archives the dosimetric data in the DICOM header. The mean number of runs per procedure ranges between 7.5 and 15.4 and the mean number of frames per procedure between 575 and 1417. Differences in kVp, mA, pulse time, distances and C-arm angulations are substantial and suggest that there exists a wide range for optimisation.

Complete loss of ICD programmability after magnetic resonance imaging

The purpose of this case report is to describe the effects of an MRI performed on a patient without realizing that an ICD has been previously implanted. After a few seconds of imaging the adversity was recognized and the examination was stopped immediately. The patient was not pacemaker dependent and had neither physical complaints nor electrocardiographic changes in the surface ECG. A consecutively performed ICD assessment showed a backup mode with standard parameters for pacing (VVI 50 beats/min) and arrhythmia detection and treatment. The device could not be programmed by the external programmer. With the exception of printing out the parameters, all software functions were no longer feasible. A device examination by the manufacturer after ICD replacement showed that a major portion of the device memory was corrupt. Even ICDs of a newer generation are susceptible to magnetic interference, with the danger of complete loss of programmability.

[Value of memory functions in implantable prostheses]

The development of memory functions with memorised electrogrammes is one of the most important technical advances in cardiac pacemakers and defibrillators. These memory functions are very useful in the management of patients with implanted prostheses. In the case of defibrillators, the memory allows evaluation and validation of appropriate treatments (shock or asymptomatic antitachycardia stimulation) or inappropriate function. The memory can also help assess the efficacy of complementary antiarrhythmic therapy or radiofrequency ablation. The incorporation of memory functions in pacemakers is more recent but no less useful. The latest generation of pacemakers have not only a therapeutic but also a diagnostic role with respect to atrial and ventricular arrhythmias. They can lead to the prescription of an antiarrhythmic or anticoagulant drug in cases of sustained atrial fibrillation confirmed by the memorised electrogrammes. The memory function is also a great aid in reprogramming stimulators in cases of overdetection (V-A cross talk). They may also be activated by the patient in cases of sporadic paroxysmal symptoms. The latest development is that of a purely diagnostic prosthesis: the implantable Holter, whose main indication is in the investigation of unexplained syncope.

[The place of telemedicine in rhythmology and cardiac pacing]

Rapid advancement in telecommunication technology has made possible automatic periodic transmission of pacemaker and implantable defibrillator data to the attending physician (home monitoring). Furthermore, technology using remote control software allows, through device programmers, interrogation of the device memory, permitting remote monitoring by physicians or technical support of the manufacturer. Potential applications of these two capabilities include a close watch over the functioning of the devices, ability to obtain an earlier diagnosis (and management) of arrhythmic events, and assistance at the time of implant procedure and routine follow up. Finally these new tools raise several questions concerning safety aspects (including reliability of transmission, encrypted transfer, restricted access of the central database), economic aspects, and physician and manufacturer's liability.

MITIS: a WWW-based medical system for managing and processing gynecological-obstetrical-radiological data

In this paper a World Wide Web (WWW)-based medical system, called MITIS, is designed and developed for the management and processing of obstetrical, gynecological and radiological medical data. The system records all the necessary medical information in terms of patient data, examinations, and operations and provides the user-expert with advanced image processing tools for the manipulation, processing and storage of ultrasound and mammographic images. The system can be installed in a hospital's Local Area Network (LAN) where it can access picture archival and communication systems (PACS) servers (if available), or any other server within the radiology department, for image archiving and retrieval, based on the digital imaging and communication in medicine (DICOM) 3.0 protocol, over TCP/IP and also it is accessible to external physicians via the hospital's Internet connection. MITIS is composed as a set of independent WWW modules (ISAPI server extension dlls) and a Win32 application (COM+ server) for mammography image processing and evaluation.

Digital image storage

Film has long been considered the gold standard for displaying and storing clinical images. But that may be changing. Digital technology--specifically digital imaging and storage technology--has advanced to the point where it can now deliver on the promises envisioned years ago. That is, the ability to provide any image, virtually anywhere, at any time--a goal that could never be achieved with film. Achieving this goal, however, requires a properly implemented digital infrastructure, including effective digital image storage. As early adopters will attest, digital image storage can be difficult to implement. It requires the careful selection and implementation of storage technologies and the continuous management of storage operations. In this Guidance Article, we address many of the issues facing the healthcare professionals charged with managing this process: We introduce the topic of medical digital storage, discussing how it is accomplished and why storing images is not that different from storing other forms of data. We review the available storage alternatives, from fast-access hard drives and RAIDs to long-term magnetic tape and optical disc storage. We delve into the issue of image compression, describing what compression is and how much can be used without affecting patient care. And we review the pertinent legal, regulatory, and management issues. When committing to a digital image workflow, it is essential that a healthcare facility give careful consideration to data storage issues, since poor choices can lead to significant long-term costs for the facility.

A Microcontroller-Based Portable Electrocardiograph Recorder

We describe a low cost portable Holter design that can be implemented with off-the-shelf components. The recorder is battery powered and includes a graphical display and keyboard. The recorder is capable of acquiring up to 48 hours of continuous electrocardiogram data at a sample rate of up to 250 Hz.

The role of atomic scale investigation in the development of nanoscale materials for information storage applications

It is well established that the response of devices based on the giant magnetoresistance (GMR) effect depends critically on film microstructure, with parameters such as interfacial abruptness, the roughness and waviness of the layers, and grain size being crucial. Such devices have applications in information storage systems, and are therefore of great technological interest as well as being of fundamental scientific interest. The layers must be studied at high spatial resolution if the microstructural parameters are to be characterized with sufficient detail to enable the effects of fabrication conditions on properties to be understood, and the techniques of high resolution electron microscopy, transmission electron microscopy chemical mapping, and atom probe microanalysis are ideally suited. This article describes the application of these techniques to a range of materials including spin valves, spin tunnel junctions, and GMR multilayers.

Sharing digital micrographs and other data files between computers

It ought to be easy to exchange digital micrographs and other computer data files with a colleague even on another continent. In practice, this often is not the case. The advantages and disadvantages of various methods that are available for exchanging data files between computers are discussed. When possible, data should be transferred through computer networking. When data are to be exchanged locally between computers with similar operating systems, the use of a local area network is recommended. For computers in commercial or academic environments that have dissimilar operating systems or are more widely spaced, the use of FTPs is recommended. Failing this, posting the data on a website and transferring by hypertext transfer protocol is suggested. If peer to peer exchange between computers in domestic environments is needed, the use of Messenger services such as Microsoft Messenger or Yahoo Messenger is the method of choice. When it is not possible to transfer the data files over the internet, single use, writable CD ROMs are the best media for transferring data. If for some reason this is not possible, DVD-R/RW, DVD+R/RW, 100 MB ZIP disks and USB flash media are potentially useful media for exchanging data files.