Multiple Breakdown Research Articles

New approach to evaluate area-dependent breakdown characteristics of dielectric polymer films

A new dielectric breakdown measurement method for determining breakdown characteristics of polymer films has been developed and evaluated. The method is based on measurement of multiple breakdowns per sample area beyond the weakest point of the film by utilizing low-energy self-healing breakdown of metallized polymer film. A data selection process based on the discharge energy characteristics of each measured self-healing breakdown is utilized prior to the statistical analysis in order to validate the mutual independence of the results. Even with a relatively small sample area, the method yields a large amount of breakdown data from a wide voltage spectrum, thus enabling the formation of detailed material-specific breakdown fingerprints. The measurement system and the area dependence of the breakdown results have been evaluated with capacitor-grade metallized film. For the statistical analysis, additively mixed Weibull distributions are utilized as multiple breakdown mechanisms are found to be operative in the dielectric. Defects in the dielectric volume are found to have a profound effect on the structure of the mixed distribution with increasing area.

Determination of the Optimal Batch Size for a Manufacturing System with Multiple Deliveries and Random Machine Breakdown

Determination of the Optimal Batch Size for a Manufacturing System with Multiple Deliveries and Random Machine Breakdown

Comparison of different aggregate stability approaches for loamy sand soils

The bio-dynamic relations of soil aggregate stability, as a widely accepted soil quality indicator, with the physical, chemical and biological soil properties are very complicated in the soil system, and there exist many methods of measuring the soil aggregate stability to establish these relations. This study aimed to evaluate different aggregate stability methodologies for loamy sand soils. The applied aggregate stability methods of the research chiefly involved sieving soil samples through either multiple sieves or a single sieve using operations of wet sieving, dry sieving, pre-wetting, slow wetting, fast wetting and mechanical breakdown. These were used either alone or in combination, and the methods were compared in terms of a detachability index (DI), which is the ratio of the Mean Weight Diameter after wet sieving (MWDW) to that before wet sieving (MWDD). The statistical analysis showed that the mean values of the DI for wet sieving by multiple sieves, fast wetting and mechanical breakdown varied significantly (*P<0.05) from other methods. Clearly, depending upon the magnitude and extent of aggregate destructive forces, the DI changed significantly, and simulating diverse physical processes which could operate sequentially or simultaneously resulted in different consequences in terms of the aggregate stability.

Contributions of Pesticide Residue Chemistry to Improving Food and Environmental Safety: Past and Present Accomplishments and Future Challenges

The principles of modern pesticide residue chemistry were articulated in the 1950s. Early authors pointed out the advantages of systematizing and standardizing analytical methods for pesticides so that they could be widely practiced and the results could be reproduced from one laboratory to the next. The availability of improved methods has led to a much more complete understanding of pesticide behavior and fate in foods and the environment. Using methods based largely upon gas chromatography (GC) and high-performance liquid chromatography (HPLC) coupled increasingly with mass spectrometry (MS) and MS(n) as the detection tool, residues can be measured at parts per billion levels and below in a variety of food and environmental matrices. Development of efficient extraction and cleanup methods, techniques such as ELISA, efficient sample preparation techniques such as QuEChERS, and automated laboratory and field instrumentation has also contributed to the tools available for use in modern pesticide residue analysis. As a result, great strides have been made in improving food and worker safety and in understanding environmental behavior and fate of pesticides. There are many challenges remaining in the field of pesticide residue chemistry that will continue to stimulate analytical chemists. New chemistries are emerging, often patterned on complex natural products. Analyzing for the parent chemicals and potentially multiple breakdown products will require analytical ingenuity. The development of more sensitive bioassays and knowledge of unintended side effects will challenge residue chemistry as well, as in the case of following the fate of environmental endocrine disruptors associated with some pesticides as well as nonpesticide contaminants from packaging materials and other familiar articles. Continued funding and other resources to ensure better training, international cooperation, and accelerated research and development activities will be a constant need in pesticide residue chemistry as it is for all areas of science that aim to mitigate or eliminate contaminants that can affect human and environmental health and safety.

Initial leakage current related to extrinsic breakdown in HfO 2/Al 2O 3 nanolaminate ALD dielectrics

Multiple successive breakdown events are reported for HfO 2/Al 2O 3 nanolaminate dielectrics grown by atomic-layer deposition. The first breakdown distribution is not a Weibull distribution and shows a long TBD tail at high failure percentiles. Analysis of the correlation between time-to-breakdown and initial current leakage allows identifying this tail with extrinsic breakdown. Screening of the data to eliminate the extrinsic tail demonstrates that the successive breakdown events are completely uncorrelated and perfectly match the successive breakdown theory. The statistical correlation between initial current and extrinsic breakdown distribution is explained in terms of variations of the unintentional interfacial SiO x layer at the silicon substrate/dielectric interface.

Acute Intravenous Synaptamine Complex Variant KB220™ “Normalizes” Neurological Dysregulation in Patients during Protracted Abstinence from Alcohol and Opiates as Observed Using Quantitative Electroencephalographic and Genetic Analysis for Reward Polymorphisms: Part 1, Pilot Study with 2 Case Reports

It is well established that in both food- and drug-addicted individuals, there is dopamine resistance due to an association with the DRD2 gene A1 allele. Evidence is emerging whereby the potential of utilizing a natural, nonaddicting, safe, putative D2 agonist may find its place in recovery from reward deficiency syndrome (RDS) in patients addicted to psychoactive chemicals. Utilizing quantitative electroencephalography (qEEG) as an imaging tool, we show the impact of Synaptamine Complex Variant KB220™ as a putative activator of the mesolimbic system. We demonstrate for the first time that its intravenous administration reduces or “normalizes” aberrant electrophysiological parameters of the reward circuitry site. For this pilot study, we report that the qEEGs of an alcoholic and a heroin abuser with existing abnormalities (ie, widespread theta and widespread alpha activity, respectively) during protracted abstinence are significantly normalized by the administration of 1 intravenous dose of Synaptamine Complex Variant KB220™. Both patients were genotyped for a number of neurotransmitter reward genes to determine to what extent they carry putative dopaminergic risk alleles that may predispose them for alcohol or heroin dependence, respectively. The genes tested included the dopamine transporter (DAT1, locus symbol SLC6A3), dopamine D4 receptor exon 3 VNTR (DRD4), DRD2 TaqIA (rs1800497), COMT val158 met SNP (rs4680), monoamine oxidase A upstream VNTR (MAOA-uVNTR), and serotonin transporter-linked polymorphic region (5HTTLPR locus symbol SLC6A4). We emphasize that these are case studies, and it would be unlikely for all individuals to carry all putative risk alleles. Based on previous research and our qEEG studies (parts 1 and 2 of this study), we cautiously suggest that long-term activation of dopaminergic receptors (ie, DRD2 receptors) will result in their proliferation and lead to enhanced “dopamine sensitivity” and an increased sense of happiness, particularly in carriers of the DRD2 A1 allele. This is supported by a clinical trial on Synaptamine Complex Variant KB220™ using intravenous administration in > 600 alcoholic patients, resulting in significant reductions in RDS behaviors. It is also confirmed by the expanded oral study on Synaptose Complex KB220Z™, published as part 2 of this study. Future studies must await both functional magnetic resonance imaging and positron emission tomography scanning to determine the acute and chronic effects of oral KB220™ on numbers of D2 receptors and direct interaction at the nucleus accumbens. Confirmation of these results in large, population-based, case-controlled experiments is necessary. These studies would provide important information that could ultimately lead to significant improvement in recovery for those with RDS and dopamine deficiency as a result of a multiple neurotransmitter signal transduction breakdown in the brain reward cascade.

The repeated replacement model – Rapid climate change and population dynamics in Late Pleistocene Europe

The disappearance of Neanderthals from the Palaeolithic record in Europe remains an enigma, even after more than 150 years of research. This paper identifies Rapid Climate Change during the Glacial period as a major factor that influences a variety of cultural, economic and demographic processes during the European Palaeolithic. In particular, and in agreement with many previous authors, climatic deterioration is put forward to explain multiple population breakdown during the European Palaeolithic, as well as to explain corresponding major cultural changes. Taking the archaeological record of the Iberian Peninsula as a case study, the Repeated Replacement Model (RRM) is proposed to explain population turnover in Europe during the most extreme climatic phases of the Glacial, the occurrence of North Atlantic Heinrich Events (HE). The strong aridity of the Mediterranean during HEs appears to have limited settlement refugia to such an extreme extent that communication networks and cultural traditions broke down and were subsequently reorganized under different socio-cultural conditions. The transition from the Middle Palaeolithic to the Aurignacian during HE 4 is one of these cultural turnover periods, which saw the final (macro-scale) extinction of Neanderthals and their widespread replacement by Anatomically Modern Humans. More specifically, and recognizable by comparisons with other climatically extreme Glacial periods (i.e. HE 3, and HE 2), the model excludes the survival of geographically wider (supra-regional) human networks, but it does allow for (micro-scale) survival of scattered groups. From this model, some kind of admixture between Neanderthals and incoming groups of modern humans would indeed have been possible on a small scale. If this climatic scenario turns out to be correct, the most spectacular thing about Neanderthal disappearance might actually lie in the seemingly unspectacular nature of the processes involved.

Simulation of the Breakdown Spots Spatial Distribution in High-K Dielectrics and Model Validation Using the Spatstat Package for R Language

The application of successive high-voltage sweeps to the gate electrode of metal/MgO/InP capacitors generates multiple breakdown spots distributed over the metal gate that can be regarded, from the spatial statistics viewpoint, as a point pattern set. The spots are associated with filamentary paths running across the oxide layer and are the result of important thermal effects occurring during the current runaway phase of the breakdown event. In this work, we analyze the spatial distribution of the spots using a software package specifically developed to that aim. The package is called Spatstat and forms part of the R language library.

Multiple alphaII-spectrin breakdown products distinguish calpain and caspase dominated necrotic and apoptotic cell death pathways

Apoptosis and oncotic necrosis in neuronal and glial cells have been documented in many neurological diseases. Distinguishing between these two major types of cell death in different neurological diseases is needed in order to better reveal the injury mechanisms so as to open up opportunities for therapy development. Accumulating evidence suggests apoptosis and oncosis epitomize the extreme ends of a broad spectrum of morphological and biochemical events. Biochemical markers that can distinguish between the calpain and caspase dominated types of cell death would help in this process. In this study, three chemical agents, maitotoxin (MTX), staurosporine (STS) and thylenediaminetetraacetic acid (EDTA), were used to induce different types of cell death in PC12 neuronal-like cells. MTX-induced necrosis, as determined by the increased levels of calpain-specific cleaved fragments of spectrin by antibodies specific to the calpain-cleaved 150 kDa alphaII-spectrin breakdown product (SBDP150) and 145 kDa alphaII-spectrin breakdown product (SBDP145). In this paradigm, there were no detectable SBDP150i and SBDP120 fragments as determined by antibodies specific to the caspase-cleaved specific fragments similar to those seen in the EDTA-mediated apoptotic PC-12 cells. In contrast to the calpain specific MTX necrosis treatment and the caspase EDTA apoptotic treatment is the STS treatment which induced both proteases as shown by the increase in all the SBDP fragments. Furthermore, compared to SBDP150, SBDP145 appears to be a more specific and sensitive biomarker for calpain activation. Taken together, our results suggested calpains and caspases which dominate the two major types of cell death could be independently discriminated by specifically examining the multiple alphaII-spectrin cleavage breakdown products.

RF CMOS reliability simulations

We present a simulation approach to assess the reliability of an RF CMOS circuit under user conditions, based on existing DC degradation models for gate-oxide breakdown and hot-carrier degradation. The simulator allows for lifetime prediction of circuits that can withstand multiple breakdown events. Simulation results show that three power amplifiers with comparable initial circuit performance show an astronomic difference in reliability. The tool thus proves to be an asset in the analog design process.

A Compact Model for Oxide Breakdown Failure Distribution in Ultrathin Oxides Showing Progressive Breakdown

The cumulative distribution of the failure time, which includes the time to first breakdown (BD) and the progressive current growth time, is the function of interest for reliability of ultrathin gate oxides. Depending on oxide area and stress conditions, oxide failure is determined by a single BD spot or by multiple competing spots. In this letter, we present an analytical compact model for the final failure distribution which is valid for any failure percentile and which is applicable to both the single and the multiple BD spot limits. This model is intended to be the core of a reliability assessment methodology either for the SiO2-based or high-k gate insulators of interest for the hp45 technology node and beyond.

Penetration and Precision of Subsurface Photodisruption in Porcine Skin Tissue With Infrared Femtosecond Laser Pulses

The surgical precision of photodisruption with ultrafast optical pulses depends on the accurate delivery of optical energy to sites of interest. As light penetration is limited in turbid tissues, localization and precision of subsurface breakdown highly depend on the interacting effects of increased power requirements and external focusing conditions. Infrared femtosecond breakdown extent in excised porcine skin tissue was investigated using a high-frequency ultrasonic technique which sensitively detected laser-induced bubbles. Using a focused laser source, optical parameters including laser fluence and focusing numerical aperture (NA) were controlled. Decreasing NA improved penetration, while increasing NA improved precision. At lower NA, penetrations of up to 1 mm could be achieved with a single laser excitation at the cost of an expanded breakdown region which reduced precision. Even at higher NA, however, maximum penetration reduced to 400 microm and precision was still limited with extended breakdown regions for focusing depths greater than 100 microm. Glycerol was used as an index matching material, which helped reduce scattering and improved penetration by 150 to 400 microm for all NAs. Nonetheless, multiple breakdown sites and the corresponding reduction in precision were observed even with glycerol treatment.

Analysis of maximum traffic flow and its breakdown on congested freeways

This study analyzes the dynamic behavior of traffic flow over time by deriving the theoretical value of flow oscillations convergence ( F ̃ ) following the breakdown of traffic flow. Modeling traffic flow fluctuations over time reflects two basic zones: the increasing demand zone that terminates approximately when the maximum flow is attained, and the oscillations zone that reflects the fluctuations of flow until its stabilization. The models in the flow-time plane introduce a new concept of “stable maximum flow” particularly for design purposes. Both converged values and observed recovery flow values represent the end of the recovery phase transition where the traffic stream approaches the free flow regime through lower flow conditions than the maximum flow conditions. A comparison between breakdown starting times and times of the maximum flow shows that in most cases, when one breakdown period (OB) is experienced, breakdown starts 21–50 min after observing the maximum flow. Modeling changes in traffic flows in the flow-time plane is emphasized for OB or multiple breakdown period (MBP) cases. The analysis of frequent OB and infrequent MBP cases allow for better controlling of the traffic flow by maintaining its flow level below maximum.

Multiple breakdown and chemical equilibrium of silicic clinopyroxene under extreme metamorphic conditions in the Kontum Massif, central Vietnam

Clinopyroxene in ultrahigh-temperature mafic granulites from the Kontum Massif in central Vietnam records multiple metamorphic stages, manifested as exsolution textures (quartz rods and orthopyroxene + hornblende + plagioclase needles), and as symplectitic intergrowths (involving clinopyroxene + plagioclase). These textures suggest a metamorphic evolution characterized by decompression and subsequent cooling from eclogite-facies to amphibolite-facies conditions through ultrahigh-temperature conditions. Quartz rods in clinopyroxene and clinopyroxene + plagioclase symplectites were formed under eclogite conditions prior to ultrahigh-temperature metamorphism. The orthopyroxene + hornblende + plagioclase needles in clinopyroxene are regarded as cooling products after ultrahightemperature metamorphism. Recalculated compositions of precursor clinopyroxene show supersilicic composition. During the metamorphic evolution, the chemical composition varies from silicic (Ca- Eskola-rich) via sodic (Jadeite-rich) to aluminous (Ca-Tschermak-rich) compositions. Presence of supersilicic clinopyroxene suggests that the granulite decompressed from possible ultrahigh-pressure conditions (ca. 800–900 °C at 2–3 GPa) preceding the ultrahigh-temperature stage (1050 °C at 1.3 GPa), which provide strong constraints on the tectonic evolution of the Indochina region, and it also provides insights on crustal exhumation at a continental collision zone. Another significant aspect of this study is that the breakdown textures of clinopyroxene and its chemical variations may provide important information in establishing pre- and post-peak evolution, especially for extremely high-temperature or high-pressure metamorphic rocks.

Postbreakdown Conduction in Ultrathin $\hbox{La}_{2} \hbox{O}_{3}$ Gate Dielectrics

The evolution of the conduction characteristics of ultrathin lanthanum oxide (La2O3) gate dielectrics that are subjected to constant and ramped electrical stresses was investigated. The samples were obtained by the electron-beam evaporation technique and annealed in situ in ultrahigh vacuum conditions to minimize the formation of an interfacial oxide layer. We have shown that the total current flowing through the device consists of two parallel contributions, where one is associated with direct and Fowler-Nordheim tunneling and the other one is associated with multiple breakdown (BD) path conduction. This latter component is sensitive to the applied stress and evolves from soft BD to diodelike conduction as the degradation proceeds. We analyzed the experimental data in terms of two well-known models for post-BD conduction. The importance of considering series and parallel resistances within these formulations is shown.

Phospholipid signals and intestinal carcinogenesis

Phospholipids are an important constituent of the cell plasma membrane and are also present in most common dietary products, being particularly abundant in milk, egg, meat and beans. Phospholipids are hydrolysed by different phospholipases to generate multiple breakdown products that affect the fate of the cells. Most phospholipids such as phosphatidylcholine, lysophosphatidylcholine, phosphatidylinositol and platelet activating factor are important for cell survival and thus may promote tumorigenesis and inflammation. Sphingomyelin is unique in the sense that its hydrolysis by sphingomyelinase and ceramidase generates several lipid messengers such as ceramide and sphingosine that inhibit cell proliferation and induce apoptosis. In the intestinal tract there is a specific type of sphingomyelinase called alkaline sphingomyelinase, which can hydrolyse sphingomyelin in both the cell membrane and the diet. The enzyme may play important roles in preventing colon cancer development and inflammation by hydrolysing sphingomyelin to generate anticancer molecules, and by counteracting the cancer-promoting effects of other phospholipids such as lysophosphatidylcholine and platelet activating factor. This mini-review highlights the signal transduction pathways activated by different phospholipids, with special attention being paid to potential implications in the development of colon cancer. Keywords: colon cancer; inflammatory bowel disease; phospholipids; signal transduction pathway; sphingomyelin; sphingomyelinase

Influence of grain structure on anisotropic localised corrosion kinetics of AA7xxx-T6 alloys

Aluminium alloys of the AA7xxx series can have very high strength but are generally susceptible to localised corrosion. In the present study, the localised corrosion kinetics for different plates of AA7xxx-T6 were investigated in different orientations, using the foil penetration method. Multiple breakdown potentials were observed on the polarisation curves and they were independent of plate orientation. The grain size and aspect ratio were measured for each plate and were shown to be important factors for the localised corrosion growth kinetics. Anisotropic localised corrosion kinetics were observed on rolled plates owing to the microstructural anisotropy and equiaxed material had localised corrosion kinetics that were independent of orientation.

Phospholipid signals and intestinal carcinogenesis

Phospholipids are an important constituent of the cell plasma membrane and are also present in most common dietary products, being particularly abundant in milk, egg, meat and beans. Phospholipids are hydrolysed by different phospholipases to generate multiple breakdown products that affect the fate of the cells. Most phospholipids such as phosphatidylcholine, lysophosphatidylcholine, phosphatidylinositol and platelet activating factor are important for cell survival and thus may promote tumorigenesis and inflammation. Sphingomyelin is unique in the sense that its hydrolysis by sphingomyelinase and ceramidase generates several lipid messengers such as ceramide and sphingosine that inhibit cell proliferation and induce apoptosis. In the intestinal tract there is a specific type of sphingomyelinase called alkaline sphingomyelinase, which can hydrolyse sphingomyelin in both the cell membrane and the diet. The enzyme may play important roles in preventing colon cancer development and inflammation by hydrolysing sphingomyelin to generate anticancer molecules, and by counteracting the cancer-promoting effects of other phospholipids such as lysophosphatidylcholine and platelet activating factor. This mini-review highlights the signal transduction pathways activated by different phospholipids, with special attention being paid to potential implications in the development of colon cancer. Keywords: colon cancer; inflammatory bowel disease; phospholipids; signal transduction pathway; sphingomyelin; sphingomyelinase

Characterizing the Ovotoxicity of Cyclophosphamide Metabolites on Cultured Mouse Ovaries

Cyclophosphamide (CPA) is reported to target dormant primordial ovarian follicles in rodents and humans. However, mechanistic studies are complicated due to the complex ovarian structure. We present here the characterization of the sensitivity of ovaries to CPA metabolites and the timing of morphological alterations induced by phosphoramide mustard (PM) in an in vitro system. Intact mouse ovaries (postnatal-day-4) were cultured in vitro and exposed to multiple breakdown products of CPA on day 0 (d0). Tissues were cultured up to d8, and then follicle counts and immunohistochemistry were performed. 4-Hydroperoxy-CPA (4-HC), a precursor of an activated form of CPA, and PM depleted primordial and primary follicles (> or =1 microM and > or =3 microM, respectively, p < 0.05); acrolein had effects on follicle numbers only under continuous exposure (> =30 microM); carboxycyclophosphamide and 4-ketocyclophosphamide reduced primordial and small primary follicles only at high concentrations (100 microM). PM-induced follicle loss became significant (p < 0.05) by d1 or d2 following exposures to 10 microM or 3 microM PM, respectively, as determined by the numbers of pyknotic or TUNEL-positive follicles. Cellular targets were oocytes in the smallest follicles, but granulosa cells in large primary follicles. TUNEL staining was observed in both cell types, but caspase-3, a marker of apoptosis, was absent from primordial follicles. In addition, a pan-caspase inhibitor could not prevent follicle losses when administered prior to PM. Thus, brief exposures to 4-HC or PM are sufficient to induce permanent follicle loss in ovaries, and PM is likely the ultimate ovotoxicant. Furthermore, the cell death pathway is likely caspase-independent.

Multiple cognitive deficits during the transition to Alzheimer's disease.

The literature on cognitive markers in preclinical AD is reviewed. The findings demonstrate that impairment in multiple cognitive domains is typically observed several years before clinical diagnosis. Measures of executive functioning, episodic memory and perceptual speed appear to be most effective at identifying at-risk individuals. The fact that these cognitive domains are most implicated in normal cognitive aging suggests that the cognitive deficit observed preclinically is not qualitatively different from that observed in normal aging. The degree of cognitive impairment prior to the diagnosis of Alzheimer's disease (AD) appears to generalize relatively well across major study characteristics, including sample ascertainment procedures, age and cognitive status of participants, as well as time to diagnosis of dementia. In episodic memory, there is evidence that the size of the preclinical deficit increases with increasing cognitive demands. The global cognitive impairment observed is highly consistent with observations that multiple brain structures and functions are affected long before the diagnosis of AD. However, there is substantial overlap in the distribution of cognitive scores between those who will and those who will not be diagnosed with AD, hence limiting the clinical utility of cognitive markers for early identification of cases. Future research should consider combining cognitive indicators with other types of markers (i.e. social, somatic, genetic, brain-based) in order to increase prediction accuracy.