Search

In the last decade we have seen a shift towards a broader application of information on IC manufacturing defects. Here an overview is given of the methods used to gather data on the defects with a focus on local defects in the interconnection layers. Next this information is applied to determine a model describing the geometrical aspects of such defects. This model is used to arrive at a definition of hard faults and soft faults and to derive a relationship between the relative number of occurrence for either fault. Because the electrical impact of some of the soft faults will be closely related to the behavior of small open circuits or gate-oxide shorts, this relationship is an indication for the extent of the quality and reliability problems. >

Cerebral Autosomal Dominant Arteriolopathy with Subcortical Infarcts and Leucoencephalopathy (CADASIL) is a recently but increasingly recognized cause of migraine with aura, early and recurrent strokes, and dementia, with an autosomal pattern of transmission. The disease is a widespread vasculopathy, but it is clinically expressed in the CNS only. Cerebral MRI is always abnormal in symptomatic patients, and sometimes in asymptomatic but affected individuals. It shows more or less confluent hypersignals on T2-weighted and flair images. A spectrum of mutations in the Notch3 gene on chromosome 19 are responsible for the disease. There is no specific treatment and the prognosis is poor. We followed three patients from 2 families with genetically confirmed CADASIL and we present their clinical characteristics. We discuss current data on this rare, but non exceptional arteriolopathy.

Seizures starting in patients over 60 years old are frequent. Diagnosis is sometimes difficult and frequently under- or overrated. Cerebrovascular disorders are the main cause of a first seizure. Because of more frequent comorbidities, physiologic changes, and a higher sensitivity to drugs, treatment has some specificity in elderly people. The aim of this paper is to present the result of a consensus meeting held in October 2004 by a Belgian French-speaking group of epileptologists and to propose guidelines for the management and the treatment of epilepsy in elderly people.

This paper investigates the test quality of asynchronous circuits using fault models that are grounded in realistic defect probabilities. As for synchronous designs, I/sub DDQ/ testing plays a prominent role in detecting CMOS manufacturing defects for asynchronous designs, too. However, for asynchronous circuits, I/sub DDQ/ testing is usually less effective because fewer states are quiescent, and our analysis shows that the test quality can only be improved by creating more quiescent states. We present a new Design-for-Test (DfT) method that provides good test quality in that all defects are detected that are likely to occur given the IC layout and process technology and that pose quality or reliability problems. Our DfT method is evaluated on three in-house manufactured designs.

In spin on glass (SOG) planarization processes yield loss can occur in between closely spaced metal lines due to the formation of tungsten residues called stringers. Stringers may cause electrical shorts between adjacent metal tracks, In this paper it is shown under what conditions stringers may occur and the extraction procedure capable of detecting locations prone to stringers in a product is proposed. The usefulness of such a procedure for both failure analysis and in line process monitoring is discussed as well.

A radioimmunoassay of urinary 6-sulphatoxymelatonin (a-MT6s) was performed in 90 normal subjects: 44 males and 46 females (17-67 years). Patients treated with betablokers or antidepressants were not included in this study. Urine samples were collected over three periods of time: 7 to 11 p.m., 11 p.m. to 7 a.m., and 7 to 11 a.m. Between 11 p.m. and 7 a.m., the subjects slept in their normal environment and had not ingested alcohol for 24 hours. We searched for a possible relation between urinary a-MT6s excretion (expressed in ng/l/h) and age. From 7 to 11 p.m. and from 7 to 11 a.m. no significant relation could be found. On the contrary, between 11 p.m. and 7 a.m. there was a significant relation indicating decrease of a-MT6s secretion with increasing age. Several linear or non-linear curve patters were tested: Boltzmann sigmoid (1(st), 2(nd), and 3(rd) degree), polynomial curves. The Boltzmann sigmoid showed the best fit judging by the r-squared value (0.152) and the runs test (p=0.64). On this curve the inflection point was located at 53 4 years (SDM, standard deviation of the mean). From 19 to 45 years, the upper sigmoid plateau was located at 1381 91 ng/l/h (SDM). The decrease was found between 45 and 60 years and the lower sigmoid plateau then stabilized at 467 370 ng/l/h (\SDM). In the study group, there was no significant difference between men and women according to the Mann-Withney test. Finally, use of oral contraceptives did not affect urinary a-MT6s (Mann-Withney).

Melatonin is a hormone mainly secreted by the pineal gland during the dark phase of the light-dark cycle. The most known function of melatonin in mammals is to transmit information concerning light-dark cycles playing the role of an active neuroendocrine transducer of environmental information. Given this chronobiologic role of pineal melatonin, it seems to be useful in the management of shift work, jet lag and some sleep disorders. In vitro like in vivo melatonin seems to be effective as an antioxidant and oncostatic agent. Melatonin may provide protection against aging process, degenerative diseases, cancer and play a role also in sexual maturation, reproduction, immune function and psychiatric illness. The administration of melatonin in the jet-lag syndrome is well codified. Further clinical research is needed for a better understanding and definition of other indications, treatment regimens and safety of the hormone. The aim of this paper is to review the current knowledge on its clinical implications.

Melatonin is a hormone mainly secreted by the pineal gland during the dark phase of the light-dark cycle. The best known function of melatonin in mammals is to transmit information concerning light-dark cycles playing the role of an active neuroendocrine transducer of environmental information. Although melatonin circadian rhythm is endogenous, based on 25 hour cycles, it is modulated by light-dark cycle. During the day, the light signal is sent to the pineal gland through a special neuronal pathway and inhibits melatonin secretion. During the night, the last neuron of this pathway which is coming from the cervical ganglion superior releases nonadrenalin in the interstitium. Nonadrenalin stimulates melatonin synthesis through cAMP accumulation. Some factors other than light can also influence melatonin levels. Electromagnetic fields, age, male sex, Cushing syndrome, hypogonadotrophic hypogonadism, alcoholism seem to be associated with lower melatonin secretion. Female sex, hypergonadotrophic hypogonadism, sport and fasting seem to be linked to higher melatonin secretion. Some pathologies and drugs can modulate some steps of the neuroanatomic pathway of melatonin synthesis. Stress has no effect. The influence of weight and height is still investigated. Once released, melatonin can act on different organs through specific receptors (retina, supra-chiasmatic nucleus, hypophysis, brain, blood vessels, digestive tract, ovaries).

The commenters argue that in the above-titled paper by M.S. Cheema and P.K. Lala (ibid., vol.27, no.8, p.1203-6, Aug. 1992) a reference has been wrongly interpreted by the authors, resulting in an incorrect impression of the defect densities. Another problem, concerning the propagation of faults to the final outputs, is also discussed. Furthermore, the commenter points out that the dynamic behavior of the method is not addressed in the original paper and that the design technique presented in the paper requires a high area overhead with which not all possible defects will be detected. >

Test development for analogue and mixed-signal circuits has become a bottleneck in the IC development trajectory. A defect-oriented test approach provides an objective test evaluation technique, which alleviates this bottleneck. This test approach, however, makes extensive use of analogue fault simulation, which is very CPU-intensive. It is shown how a standard (digital) VHDL simulation environment can be used to drastically reduce the fault simulation time for complex analogue circuits.