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This paper reviews the recent historical trends of the NAND Flash technology, highlighting the evolution of its main parameters and explaining what allowed it to become not only the most important integrated solution for nonvolatile storage of high volumes of data but also a strong rival eroding the market share of hard-disk drives. The scaling trend followed by planar arrays will be discussed with close attention, along with the major physical constraints impacting the performance and the reliability of modern deca-nanometer technologies. This will make clear why the development of further planar nodes with feature size below ~15 nm, representing today’s state of the art, can be considered less favorable than turning all the efforts toward the integration of 3-D arrays. The most promising 3-D architectures will then be reviewed, discussing their benefits and issues and addressing the impact of the change of the integration paradigm from the standpoint of the major NAND applications.

Maize harvested in the Centane region of the former Transkei, Eastern Cape Province, South Africa, by subsistence farmers has been shown over many seasons to be contaminated with fumonisin mycotoxins. However, there are limited data on the presence of other mycotoxins. Two multimycotoxin LC-MS/MS methods were applied to good and moldy maize samples, as separated by the farmers themselves from the 2011 harvest. One method involved extract cleanup on multitoxin immunoaffinity columns before LC-MS/MS analysis for aflatoxins, fumonisins, deoxynivalenol (DON), zearalenone (ZEN), and T-2 and HT-2 toxins. The other method was based on a "dilute-and-shoot" approach for the above mycotoxins and a wide range of other fungal secondary metabolites. Both methods showed high incidences of fumonisins B1 and B2 (FB1 and FB2) in good maize (100% for both by the first method, means were 2083 and 927 μg/kg for the two analogues; 93% for both by the second method, positive means of 2764 and 1050 μg/kg, respectively). All samples of moldy maize were contaminated (mean FB1 of 27.64 and 35.98 mg/kg, respectively; mean FB2 of 10.58 and 14.14 mg/kg, respectively). Comparison of the two methods for FB1 and FB2 over the entire range of samples gave R(2) values 0.9144 and 0.8859, respectively. Low levels of DON were found by both methods (positive means of 12 and 4.7 μg/kg in good maize, respectively, and of 14 and 5.8 μg/kg in moldy maize, respectively). ZEN was determined with positive means of 108 and 25 μg/kg in good maize, respectively, and of 111 and 135 μg/kg in moldy maize, respectively. No aflatoxins, OTA, or T-2 or HT-2 toxins were detected. A wide range of other Fusarium , Aspergillus , Alternaria , and Penicillium mycotoxins and secondary metabolites were determined.

The multi-biomarker approach was used to validate urinary biomarkers in piglets administered boluses contaminated with mixtures of deoxynivalenol (DON), aflatoxin B1 (AFB1), fumonisin B1 (FB1), zearalenone (ZEA) and ochratoxin A (OTA) at different concentrations. Boluses contaminated with mycotoxins were prepared by slurrying and freezedrying feed material fortified with culture extracts of selected toxigenic fungi. Piglets were individually placed in metabolic cages to collect urine before gavage and 24 h post dose. Urine samples were hydrolysed with β-glucuronidase and analysed by a multi-biomarker LC-MS/MS method developed and validated to identify and measure biomarkers of FB1, OTA, DON, ZEA and AFB1. Urinary levels of FB1, OTA, DON + de-epoxy-deoxynivalenol, ZEA + alphazearalenol and aflatoxin M1 were selected as biomarkers of FB1, OTA, DON, ZEA and AFB1, respectively. Mean percentages of dietary mycotoxins excreted as biomarkers in 24 h post dose urine were 36.8% for ZEA, 28.5% for DON, 2.6% FB1, 2.6% for OTA and 2.5% for AFB1. A good correlation was observed between the amount of mycotoxins ingested and the amount of relevant biomarkers excreted in 24 h post dose urine. Linear dose-response correlation coefficients ranged between 0.68 and 0.78 for the tested couples of mycotoxin/biomarker. The good sensitivity of the LC-MS/MS method and the good dose-response correlations observed in this study permitted to validate the selected mycotoxin biomarkers in piglets at dietary levels close to the maximum permitted levels reported in Commission Directive 2003/100/EC for AFB1 and the guidance values reported in Commission Recommendation 2006/576/EC for DON, ZEA, OTA and FB1.

In this work, we present clear experimental results pointing to a new microscopic picture for cycling-induced charge trapping/detrapping in Flash memories. In particular, the evidence gathered from experiments designed to investigate the dependence of charge detrapping on cell threshold-voltage reveals that the simple and widely used model based only on carrier exchange between oxide defects and substrate is not enough to explain the main features of the phenomenon. We then propose a new microscopic description of the detrapping phenomenology, including structural relaxation of oxide defects as a limiting step enabling carrier exchange. This new microscopic picture for the oxide defects is, finally, implemented in a statistical model able to reproduce the charge trapping/detrapping dynamics and the consequent threshold-voltage instabilities along the memory array lifetime.

By using our 16-nm NAND Flash technology as a test vehicle, in this paper, we summarize all the experimental evidence that we have gathered so far on the phenomenology of cycling-induced charge trapping/detrapping in Flash memories. In particular, results from experiments conceived to explore the dependence of charge detrapping on cell memory state reveal that the phenomenon involves more than the simple capture and emission of charge carriers in tunnel-oxide defects. Besides, the thermal activation of charge trapping is highlighted for the first time, along with the detailed dynamics leading to the increase of the trapped charge as cell cycling proceeds. These results allow to lay some cornerstones for the microscopic description of cyclinginduced charge trapping/detrapping in Flash memories. From these cornerstones, in the companion paper (Resnati et al. , 2016), a new physical picture for the trapping/detrapping processes will be proposed and implemented in a statistical model able to reproduce their corresponding threshold-voltage instabilities over array lifetime.

This study examines the diversity of spore-forming bacteria isolated from raw materials/bread using molecular methods along with a rapid and innovative technology, the FT-NIR spectroscopy. Microbiological analysis showed that 23% of semolina and 42% of other raw materials (including grain, brewer yeast, improvers) contained more than 100 spores/g and more than 50% of each kind of sample was contaminated at a level ranging from 1 to 100 spores/g. A high bacterial diversity characterized raw materials. In total 176 isolates were collected and characterized: 13 bacterial species belonging to Bacillus (10) and Paenibacillus (3) genera were identified by sequencing of 16S rRNA, gyrA or gyrB genes. The two closely related species Bacillus amyloliquefaciens (strain N45.1) and Bacillus subtilis (strain S63) were also analyzed by the spectroscopic technique FT-NIR. This analysis gave clear discrimination between the strains in the score plot obtained by the PCA and allowed to identify the spectral region 5600–4000 cm− 1 as the information-rich region for discrimination. B. amyloliquefaciens, possibly misidentified as B. subtilis in previous studies, was recognized as the most frequent species, found also in ropy bread. Moreover, the screening test for rope production indicated that mainly B. amyloliquefaciens, together with B. subtilis and Bacillus pumilus, could cause spoilage in bread, even if the last two species were represented by a low number of isolates. The Bacillus cereus group and Bacillus megaterium showed a lower percentage (30–70%) of isolates potentially able to cause the rope, but considering the high number of B. cereus group isolates detected in this study, this bacterial group should also be considered important in rope spoilage. In conclusion, results demonstrate that raw materials used to produce bread represent a rich source of spore-forming bacteria, therefore their microbiological quality should be monitored before use. Moreover, this study highlights for the first time the importance of the species B. amyloliquefaciens in rope spoilage and indicates that other species may also cause this alteration although strains of the same species may behave differently.

A comparison study of different extraction and clean-up procedures for the liquid chromatographic analysis of fumonisins B(1) (FB(1)) and B(2) (FB(2)) in corn masa flour was performed. The procedures included extraction (heat or room temperature) with acidic conditions or EDTA-containing solvents, and clean-up by immunoaffinity or C18 solid-phase extraction columns. Thereafter an analytical method was optimised using extraction with an acidic mixture of methanol-acetonitrile-citrate/phosphate buffer, clean-up through the immunoaffinity column and determination of fumonisins by liquid chromatography with automated pre-column derivatisation with o-phthaldialdehyde reagent. Recovery experiments performed on yellow, white and blue masa flours at spiking levels of 400, 800 and 1200 µg kg(-1) FB(1) and of 100, 200 and 300 µg kg(-1) FB(2) gave overall mean recoveries of 99% (±6%) for FB(1) and 88% (±6%) for FB(2). Good recoveries (higher than 90% for both FB(1) and FB(2)) were also obtained with corn tortilla chips. The limits of quantification of the method (signal-to-noise ratio of 10) were 25 µg kg(-1) for FB(1) and 17 µg kg(-1) for FB(2). The method was tested on different commercial corn masa flours as well as on white and yellow corn tortilla chips, showing fumonisin contamination levels (FB(1) + FB(2)) up to 1800 µg kg(-1) (FB(1) + FB(2)) in masa flour and 960 µg kg(-1) in tortilla chips. Over 30% of masa flours originating from Mexico exceeded the European Union maximum permitted level.

Aspergillus niger has been recently found to produce fumonisin B(2) (FB(2)). Thirty-one strains belonging to four Aspergillus species isolated from grape were evaluated for FB(2) production on agar plates. Four out of eight strains of A. niger produced FB(2) (29-293 microg g(-1)). None of the strains of A. uvarum (n = 7), A. tubingensis (8) and A. carbonarius (8) produced detectable amounts of toxin. The capability to produce FB(2) was also confirmed by some A. niger strains artificially inoculated on grape berries. Natural occurrence of FB(2), at levels of 0.01 and 0.4 microg ml(-1), was found in two samples of must collected in Apulian cellars in 2007. This is the first report of FB(2) contamination in must. These findings suggest that there is a potential risk of exposure to FB(2) in the grape-wine chain for consumers and that A. niger may represent the major fumonisin-producing species among black Aspergilli occurring on grapes.

Fusarium is a genus frequently contaminating different agricultural products and is also a renown producer of Trichothecenes1. This group of mycotoxins can be further subdivided into subgroups with T-2/HT-2 toxins and deoxynivalenol being the main representatives of the type A and B respectively. In general Trichothecenes are responsible for a wide variety of toxic effects in humans and animals. Within the type class A, in particular, T-2 and HT-2 toxins represent the most acutely toxic compounds2 and have been lately reviewed by EFSA3. In human health risk assessment, ingestion of contaminated food is considered the major route of human exposure to these compounds although only a smaller amount will be further available for absorption during its transit along the gut4. In vitro digestion models have been used to evaluate mycotoxins bioaccessibility during the intestinal transit. As a result, the bioaccessibility can be calculated representing a measure for the assessment of mycotoxin bioavailability in food. Some investigations have been already carried out in the past by our group in order to assess T-2 and HT-2 bioaccessibility in bread chosen as reference food model5 In this note we describe a study aimed to investigate toxicity of gastro-duodenal digests of mycotoxins contaminated bread samples collected along the digestion time-course, assayed on RPMI lymphoid B cell line, as a sensitive cellular model. In parallel, a chemical quantification of T-2 and HT-2 toxins contaminating the bread digests was accomplished along the gastric and duodenal phase. The digestive fluids undergoing chemical and toxicological analysis, were collected at the beginning and end of the gastric phase, and after completion of the duodenal phase Results proved that a correlation between HT-2 content and toxicity did exist in digestive fluids although a more persistent toxic activity was noticed in the later stage of the duodenal phase.

This paper highlights that cycling-induced threshold-voltage instabilities in nanoscale NAND Flash technologies display a non-negligible dependence on the background pattern of the memory array during idle/bake periods. Experimental results clearly reveal, in fact, that instabilities in a (victim) cell do not depend only on its memory state, but also on the memory state of its first neighboring (aggressor) cells. The magnitude of this new cell-to-cell interference effect, moreover, appears to depend on the memory state of the victim cell, decreasing with the increase of its threshold-voltage level. From all of the gathered experimental evidence a physical picture explaining the phenomenon is provided, which is, finally, confirmed with the help of numerical simulations.

The development of a surface plasmon resonance (SPR)-based biosensor tailored to the fast detection of egg-related fining allergens in wines is herein described. Ovalbumin (OVA) was chosen as the target protein to be monitored due to its highest abundance in the egg white powder, a typical fining agent used by the winery industry to promote wine clarification. A direct assay was designed, basing on the use of polyclonal anti-OVA antibody as bio-specific receptor. With the aim of optimizing the assay conditions, different parameters able to influence the final biosensor response were carefully investigated (i.e., pH, ionic strength, and additional surfactant concentration). After the fine tuning of these parameters, the assay was tested in the direct analysis of OVA in commercial wines artificially contaminated with egg white powder at different concentration levels in order to assess the reliability of the biosensor in detecting traces of OVA in complex matrices. The devised assay allowed to trace, in a short analysis time and with a minimal sample pre-treatment required, the presence of egg allergens at the lowest concentration comprised between 0.03 and 0.2 ?g/mL. Finally, the response provided by the developed biosensor was correlated with an established liquid chromatography mass spectrometry (LC-MS) method developed in our laboratories, and performances of both approaches were assessed for the fast monitoring of egg allergen contamination in fined wines.,[Figure not available: see fulltext.]

The aim of this work was to check the efficacy of bovine lactoferrin hydrolyzed by pepsin (LFH) to prevent blue discoloration of Mozzarella cheese delaying the growth of the related spoilage bacteria. Among 64 Pseudomonas fluorescens strains, isolated from 105 Mozzarella samples, only ten developed blue discoloration in cold-stored Mozzarella cheese slices. When Mozzarella cheese samples from dairy were treated with LFH and inoculated with a selected P.fluorescens strain, no pigmentation and changes in casein profiles were found up to 14 days of cold storage. In addition, starting from day 5, the count of P.fluorescens spoiling strain was steadily ca. one log cycle lower than that of LFH-free samples. ESI-Orbitrap-based mass spectrometry analyses allowed to reveal the pigment leucoindigoidine only in the blue LFH-free cheese samples indicating that this compound could be considered a chemical marker of this alteration. For the first time, an innovative mild approach, based on the antimicrobial activity of milk protein hydrolysates, for counteracting blue Mozzarella event and controlling psychrotrophic pigmenting pseudomonads, is here reported. © 2014 Elsevier Ltd.

We present the first single-electron analysis of the program operation of NAND Flash arrays. The analysis leads, first of all, to a direct extraction not only of the average value but also of the statistical spread of the control-gate to floating-gate cell capacitance (Cpp). This allows, then, to assess the impact of Cpp variability, electron injection statistics and read noise on the distribution of the threshold-voltage shift coming from a programming pulse applied to the array cells. Finally, the electron leakage through the inter-gate dielectric along program is easily and directly quantified under real operating conditions.

Fourier-transform-near infrared (FT-NIR) spectroscopy has been used to develop quantitative and classification models for the prediction of deoxynivalenol (DON) levels in durum wheat samples. Partial least-squares (PLS) regression analysis was used to determine DON in wheat samples in the range of &lt, 50–16,000 µg/kg DON. The model displayed a large root mean square error of prediction value (1,977 µg/kg) as compared to the EU maximum limit for DON in unprocessed durum wheat (i.e., 1,750 µg/kg), thus making the PLS approach unsuitable for quantitative prediction of DON in durum wheat. Linear discriminant analysis (LDA) was successfully used to differentiate wheat samples based on their DON content. A first approach used LDA to group wheat samples into three classes: A (DON ≤ 1,000 µg/kg), B (1,000 &lt, DON ≤ 2,500 µg/kg), and C (DON &gt, 2,500 µg/kg) (LDA I). A second approach was used to discriminate highly contaminated wheat samples based on three different cut-off limits, namely 1,000 (LDA II), 1,200 (LDA III) and 1,400 µg/kg DON (LDA IV). The overall classification and false compliant rates for the three models were 75%–90% and 3%–7%, respectively, with model LDA IV using a cut-off of 1,400 µg/kg fulfilling the requirement of the European official guidelines for screening methods. These findings confirmed the suitability of FT-NIR to screen a large number of wheat samples for DON contamination and to verify the compliance with EU regulation.

A rapid and accurate fluorescence polarization (FP) immunoassay has been optimized for the determination of deoxynivalenol (DON) in wheat bran and whole-wheat flour. A preliminary treatment with activated charcoal was used to eliminate the strong matrix effect due to highly colored interfering compounds present in raw wheat bran extracts. In particular, matrix effect was removed by adding activated charcoal to the wheat bran extract (3.5 mg/mL) and mixing for 3 min of incubation time prior to the FP immunoassay analysis. No preliminary treatment was necessary for whole-wheat flour. Average recoveries from samples spiked with DON at levels of 500, 1,000, and 1,500 mu g/kg were 95 % for wheat bran and 94 % for whole-wheat flour, with relative standard deviation generally lower than 13 %. Limits of quantification of the optimized FP immunoassay were 120 mu g/kg for both matrices. The overall time of analysis was lower than 15 min for wheat bran and 10 min for whole-wheat flour. Good correlations (r > 0.971) were observed between DON contents obtained by both FP immunoassay and high-performance liquid chromatography with immunoaffinity cleanup for 37 and 23 samples of naturally contaminated wheat bran and whole-wheat flour, respectively. These results show that the FP immunoassay is suitable for high-throughput screening as well as for quantitative determination of DON in wheat bran and whole-wheat flour.

Fungal volatile metabolites can be used as an indicator of mycotoxins occurrence in cereals. A rapid, easy-to-perform and non-invasive method using an electronic nose based on metal oxide sensors was developed to distinguish the quality of durum wheat samples in three classes based on the content of the mycotoxin deoxynivalenol (DON): class A ([DON] 2500 μg/kg). Two different approaches were tested by performing 525 analyses of naturally contaminated durum wheat either on whole and ground kernels. Discriminant Function Analysis (DFA) provided calibration models that permitted to classify wheat samples with mean recognition percentages (R) for whole and ground kernels of 69.3% and 86.7%, respectively. Samples belonging to class A were better recognized than those belonging to classes B and C. The e-nose method applied to the analysis of ground wheat showed highest mean recognition percentage (R = 82.1%) in validation. By considering data with recognition percentage rate (Rr) higher than 80% in validation, performances of this method were further improved in terms of either mean recognition percentage (R = 90.1%) and percentage of misclassified samples (4%). An SPME-GC–MS method was also developed that allowed to characterize the pattern of volatile compounds of durum wheat samples. A positive (trichodiene, longifolene, 3-methyl butanal, tridecane, γ-caprolactone, 6,10,14-trimethyl-2-pentadecanone) or negative (hexadecane, 2,3,7-trimethyl-decane, 4,6-dimethyl-dodecane) association with DON content was observed. These results confirm that the developed e-nose method could be used as useful tool for high throughput screening of DON contamination in durum wheat.

We analyzed the sensitivity of 45-nm phase change memory cells to neutrons and heavy ions. No errors have been recorded with neutrons with a terrestrial-like spectrum. With heavy ions, bit upsets have been observed at high incidence angle and high linear energy transfer, conditions possible only in space. Physical mechanisms have been investigated, concluding that the thermal spike model may explain the observed results.

A culture-independent and two culture-dependent real time (rt-) PCR approaches were developed to quantitatively identify Listeria monocytogenes in raw milk and soft cheeses. The optimised rt-PCR revealed 100% inclusivity and exclusivity. DNA- and cell-based standard curves showed a good linearity of response (R2 ≥ 0.987 and R2 ≥ 0.998, respectively) for five orders of magnitude (39 × 105 – 3 × 100 genome equivalents and 106–101 CFU equivalents, respectively) with about 100% relative accuracy and inter-assay variability ≤0.90%. Up to 1 genome equivalent/and 10 CFU/reaction were quantified in the DNA and cell standard curves, respectively. The rt-PCR was then combined with a liquid- (MPN technique) or a solid- (ALOA and PALCAM) based enumeration. The diagnostic sensitivity of the different approaches was investigated in artificially contaminated raw milk and soft cheeses. The rt-PCR culture-independent approach performed well in raw milk and (with a lower sensitivity) in stracchino cheese-based standard curves. MPN/rt-PCR was the best approach to enumerate low levels of L. monocytogenes in raw milk and stracchino cheese, while the ALOA-based rt-PCR quantification was more effective than the PALCAM-based. These performances were confirmed when 23 real samples of raw milk and soft cheeses by both the rt-PCR approaches were assayed.

We present the first evidence of single event upsets in 45-nm phase change memories caused by high linear energy transfer (LET) heavy ions at tilted angles along the word line. An- gular and LET dependences are presented, together with a discus- sion of the possible underlying mechanisms. The occurrence of a thermal spike, due to the ion passage, close to the heater/storage element interface is identified as the most plausible explanation. The upset cross section is compared with that of NOR Flash and finally the impact of scaling on the sensitivity of future memories is analyzed.

[object Object]The gastrointestinal tract is the main target of exposure to mycotoxin fumonisin B1 (FB1), common natural contaminant in food. Previous studies reported that proliferating cells are more sensitive than confluent cells to the toxic effect of FB1. This study aims to investigate, by dose- and time-dependent experiments on human colon proliferating intestinal cell line (HT-29), the modifications induced by FB1 at concentrations ranging from 0.25 to 69 lM. The choice of highest FB1 concentration considered the low toxicity previously reported on intestinal cell lines, whereas the lowest one corresponded to the lower FBs levels permitted by European Commission Regulation. Different functional parameters were tested such as cell proliferation, oxidative status, immunomodulatory effect and changes in membrane microviscosity. In addition FB1- FITC localization in this cell line was assessed by using confocal laser scanning microscopy. Lipid peroxidation induction was the main and early (12 h) effect induced by FB1 at concentrations ranging from 0.5 to 69 lM, followed by inhibition of cell proliferation (up to 8.6 lM), the immunomodulatory effect (up to 17.2 lM), by assessing IL-8 secretion, and increase in membrane microviscosity (up to 34.5 lM). The toxic effects observed in different functional parameters were not dose-dependent and could be the consequence of the FB1 intracytoplasmatic localization as confirmed by confocal microscopy results. The different timescales and concentrations active of different functional parameters could suggest different cellular targets of FB1.

We present a semi-analytical model for the description of charge trapping and detrapping phenomena occurring during cycling and idle periods in NAND Flash memories. The model is based on a statistical distribution of detrapping time constants that is affected by the composition of cycles and idle periods and accounts for charge discreteness, statistical charge capture and emission and statistical distribution of the threshold-voltage shift due to single detrapping events. The model can reproduce the experimental data under different conditions and allows to develop and monitor accelerated schemes able to mimic realistic on-field usage of the memory device.

Starting from the theoretical background on the detrapping process in nanoscale Flash memories given in Part I of this paper [1], we address here the effect of idle periods, temperature, and program/erase cycles on the spectral distribution of detrapping events and, in turn, on threshold-voltage instabilities appearing during a data retention time stretch. In so doing, we come to a comprehensive model able to deal with threshold-voltage instabilities from whatever on-field usage or testing scheme of the memory array, carefully accounting for both charge trapping and detrapping, and reproducing distributed-cycling effects. The model represents a valuable tool for the predictive reliability analysis of Flash technologies and for the development of accelerated experimental schemes for the assessment of post-cycling thereshold-voltage instabilities coming from charge detrapping.

Liquid chromatography coupled with single or tandem mass spectrometry (LC-MS/(MS)) is routinely used for the simultaneous determination of mycotoxins in food and feed although official methods using this technique have not yet been adopted by the European Committee for Standardization and the Association of Analytical Communities. A proficiency test (PT) was conducted for the simultaneous determination of up to 11 mycotoxins (aflatoxin B 1 (AFB 1 ), aflatoxin B 2 (AFB 2 ), aflatoxin G 1 (AFG 1 ), aflatoxin G 2 (AFG 2 ), ochratoxin A (OTA), deoxynivalenol (DON), T-2 toxin (T-2), HT-2 toxin (HT-2), zearalenone (ZEA), fumonisin B 1 (FB 1 ) and fumonisin B 2 (FB 2 )) in maize using LC-MS/(MS) to benchmark laboratories currently using this technique and to obtain information on currently used methodologies and method-related performances. Each participant received the following: instructions; a comprehensive questionnaire; a mixed mycotoxins calibration solution; a spiking solution (AFB 1 , AFB 2 , AFG 1 and AFG 2 , OTA, DON, T-2, HT-2, ZEA, FB 1 and FB 2 ); and two test materials, namely a contaminated maize sample and a blank maize sample to be spiked with a spiking solution containing 11 mycotoxins. Laboratory results were rated with z-scores. Of the 64 laboratories enrolled in the PT, 41 laboratories from 14 countries returned 43 sets of results for various combinations of analytes. The majority of laboratories (61%) reported results for all 11 mycotoxins, whereas the remaining laboratories reported results for a restricted combination (from 2 to 10 analytes). For contaminated maize and spiked maize the percentage of satisfactory z-score values (|z| ≤2) were: DON 55% and 49%, FB 1 50% and 30%, FB 2 52% and 38%, ZEA 68% and 64%, T-2+HT-2 toxins 82% and 85%, OTA 58% and 60%, AFB 1 56% and 62%, AFG 1 73% and 84%, AFB 2 40% and 78%, AFG 2 64% and 78%, respectively. The poorest performance (|z| >3) was obtained for FB 1 (31%), FB 2 (32%), AFB 1 (32%) and AFB 2 (32%) in contaminated maize and for DON (35%), FB 1 (63%) and FB 2 (52%) in spiked maize. Mean recovery results were acceptable for all mycotoxins (74% to 109%), except for fumonisins, where these were unacceptably high (159% for FB 1 and 163% for FB 2 ). A robust and reliable method for simultaneous determination of 11 mycotoxins in maize could not be identified from the results of this PT. Additional experimental work is necessary to set up a method suitable for inter-laboratory validation. The results of this PT and the relevant method’s details can be useful to identify methodology strengths and weaknesses.

The risks associated with the presence of hidden allergens in the food chain have raised the need for fast, sensitive, and reliable methods to trace food allergens in different commodities. We highlight advances and future trends in biosensor systems applied to food-allergen management. We discuss critical aspects of biosensor development with particular emphasis on integrating nanotechnology.

A sensitive and accurate fluorescence polarization (FP) immunoassay has been developed for the determination of ochratoxin A (OTA) in naturally contaminated wheat samples. A fluorescein-labeled OTA tracer was synthesized, and its binding response with three monoclonal antibodies was tested. The most sensitive competitive FP immunoassay showed an IC50 value of 0.48 ng/mL with a negligible cross-reactivity for ochratoxin B (1.7 %) and no cross-reactivity with other mycotoxins commonly occurring in wheat. The wheat sample was extracted with acetonitrile/water (60:40, v/v) and purified by a rapid solid-phase extraction procedure using an aminopropyl column prior to the FP immunoassay. The overall time of analysis was less than 20 min. The average recovery from spiked wheat samples (3 to 10 mu g/kg) was 87 %, with relative standard deviations generally lower than 6 %. Limits of detection and quantification were 0.8 and 2.0 mu g/kg, respectively. The trueness of the method was assessed by using two reference materials for OTA showing good accuracy and precision. A good correlation (r = 0.995) was observed between OTA contamination of 19 naturally contaminated wheat samples analyzed by both FP immunoassay and high-performance liquid chromatography/immunoaffinity clean-up used as reference method. These results show that the developed FP method is suitable for high-throughput screening, as well as for reliable quantitative determination of OTA in wheat at level far below the EU regulatory limits.

We study the response of NAND Flash memories to neutron and alpha particle exposure, with both Single- and Multi-Level Cell architecture devices. We analyze the error rate in the terrestrial environment and discuss scaling trends.

We investigate proton-induced upsets in state-of-the-art NAND Flash memories, down to the 25-nm node. The most striking result is the opposite behavior of Multi-Level Cell (MLC) and Single-Level Cell (SLC) devices, in terms of floating gate error cross section as a function of proton energy. In fact, the cross section increases with proton energy in SLC whereas it decreases in MLC. The reason for this behavior is studied through comparison of heavy-ion data and device simulations. The main factors that determine proton energy dependence are discussed, such as the energy dependence of nuclear cross section between protons and chip materials, the LET, energy, and angular distributions of the generated secondaries, but also the heavy-ion and total dose response of the studied devices. Proton irradiation effects in the control circuitry of NAND Flash memories are shown as well.

This paper shows that the reliability characterization of nanoscale Flash memories requires an accurate control of the adopted experimental tests, preventing spurious issues to emerge and alter the basic conclusions on the investigated reliability constraints. To this aim, the paper reports a case study on a 45-nm NOR technology, where the experimental investigation of the activation energy for damage recovery during post-cycling bakes and of distributed-cycling effects is substantially affected by parasitic threshold-voltage (VT) drifts, activated by the repeated acquisition of the whole array VT map during the experiment. Only when this spurious effect is taken into account, the typical 1.1-eV activation energy for damage recovery and the effectiveness of the conventional distributed-cycling schemes are correctly demonstrated on the investigated technology.

A multiplex dipstick immunoassay based method for the simultaneous determination of major Fusarium toxins, namely zearalenone, T-2 and HT-2 toxins, deoxynivalenol and fumonisins in wheat, oats and maize has been developed. The dipstick format was based on an indirect competitive approach. Four test lines (mycotoxin-BSA conjugates) and one control line were located on the strip membrane. Labelled antibodies were freeze-dried within the microwell. Two matrix-related sample preparation protocols have been developed for wheat/oats (not containing fumonisins) and maize (containing fumonisins) respectively. The use of a methanol/water mixture for sample preparation allowed recoveries in the range 73-109% for all mycotoxins in all tested cereals, with relative standard deviation less than 10%. The optimized immunoassay was able to detect target mycotoxins at cut off levels equal to 80% of EU maximum permitted levels, i.e. 280, 400, 1400 and 3200 μg kg(-1), respectively, for zearalenone, T-2/HT-2 toxins, deoxynivalenol and fumonisins in maize, and 80, 400 and 1400 μg kg(-1), respectively, for zearalenone, T-2/HT-2 toxins and deoxynivalenol in wheat and oats. Analysis of naturally contaminated samples resulted in a good agreement between multiplex dipstick and validated confirmatory LC-MS/MS. The percentage of false positive results was less than or equal to 13%, whereas no false negative results were obtained. Data on the presence/absence of 6 mycotoxins at levels close to EU regulatory levels were obtained within 30 min. The proposed immunoassay protocol is rapid, inexpensive, easy-to-use and fit for purpose of rapid screening of mycotoxins in cereals.

We investigate atmospheric neutron effects on floating-gate cells in NAND Flash memory devices. Charge loss is shown to occur, particularly at the highest program levels, causing raw bit errors in multilevel cell NAND, but to an extent that does not challenge current mandatory error correction specifications. We discuss the physical mechanisms and analyze scaling trends, which show a rapid increase in sensitivity for decreasing feature size.

The significance of laboratory sample preparation for the determination of two important mycotoxins, ochratoxin A (OTA) and deoxynivalenol (DON), in wheat was investigated by comparing water-slurry mixing and dry-milling procedures. The distribution of OTA and DON in 10 kg samples of naturally contaminated wheat was established by analyzing one hundred 100 g subsamples of each sample. A normal distribution and a good repeatability of DON measurements was observed for both water-slurry mixing (mean 2290 μg/kg, CV 4.6%, median 2290 μg/kg) and dry milling (mean 2310 μg/kg, CV 6.4%, median 2290 μg/kg) procedures. For OTA determinations, reliable results could be obtained only by slurry mixing sample preparation (mean 2.62 μg/kg, CV 4.0%, median 2.62 μg/kg), whereas dry-milling comminution resulted in an inhomogeneous distribution with a high variability (mean 0.83 μg/kg, CV 75.2%, median 0.60 μg/kg) and a positive skewness (2.12). Ad hoc experiments were performed on different size portions of the same sample (10 kg) to assess accuracy and precision of the comminution/homogenization procedures (slurry mixing and dry milling). Very good results were obtained for DON determination with both procedures in terms of accuracy (>98.7% of the “weighted value”) and precision (CV

Ochratoxin A (OTA), a mycotoxin produced by Aspergillus and Penicillium species, is composed of a dihydroisocoumarin ring linked to phenylalanine, and its biosynthetic pathway has not yet been completely elucidated. Most of the knowledge regarding the genetic and enzymatic aspects of OTA biosynthesis has been elucidated in Penicillium species. In Aspergillus species, only pks genes involved in the initial steps of the pathway have been partially characterized. In our study, the inactivation of a gene encoding a nonribosomal peptide synthetase (NRPS) in OTA-producing A. carbonarius ITEM 5010 has eliminated the ability of this fungus to produce OTA. This is the first report on the involvement of an nrps gene product in OTA biosynthetic pathway in an Aspergillus species. The absence of OTA and ochratoxin α, the isocoumaric derivative of OTA, and the concomitant increase of ochratoxin β, the dechloro analog of ochratoxin α, were observed in the liquid culture of transformed strain. The data provide the first evidence that the enzymatic step adding phenylalanine to polyketide dihydroisocoumarin precedes the chlorination step to form OTA in A. carbonarius and that ochratoxin α is a product of hydrolysis of OTA, giving an interesting new insight into the biosynthetic pathway of the toxin.

European intake estimates indicate that the presence of HT-2 and T-2 toxins in cereals, mainly in oats, can be of concern for human health. Therefore, the development of sensitive, rapid and reliable methods for determining these mycotoxins in cereals, in particular oats, has high priority. A rapid ultra-performance liquid chromatographic (UPLC) method has been developed for the simultaneous determination of HT-2 and T-2 toxins in oats and wheat at μg kg(-1) level. Ground samples were extracted with methanol/water (90:10, v/v) and the diluted extracts were cleaned up through immunoaffinity columns. HT-2 and T-2 toxins were separated and quantified by UPLC with photodiode array (PDA) detector (λ=202 nm) in less than 5 min. Mean recoveries from blank oats samples spiked with HT-2 and T-2 toxins at levels of 50-1000 μg kg(-1) ranged from 87 to 96%, with relative standard deviations (RSDs) lower than 7%; mean recoveries from wheat spiked with HT-2 and T-2 toxins at levels of 25-100 μg kg(-1) ranged from 91 to 103%, with RSDs lower than 5%. The limit of detection of the method was 8 μg kg(-1) for both toxins (signal-to-noise ratio 3:1). The method was successfully applied to the analysis of HT-2 and T-2 toxins in naturally contaminated oats and wheat samples. A good correlation was found by comparative analysis of naturally contaminated samples of oats (r=0.9985) and wheat (r=0.9058) using the proposed method or a reliable HPLC method with fluorescence detection after pre-column derivatization with 1-anthroylnitrile.

The corruption of the information stored in floating gate cells due to heavy-ion strikes is a critical issue for the use of Flash memories in space. In this work we examine how feature size scaling affects the single event upset sensitivity of multi-level floating gate cells with NAND architecture. Both experimental data on heavy-ion irradiation and analytical modeling are used to study how the threshold LET and saturation cross section depend on the cell feature size. A comparison is also carried out between multi-level and single-level floating gate cells.

A rapid fluorescence polarization (FP) immunoassay has been developed for the simultaneous determination of T-2 and HT-2 toxins in naturally contaminated wheat samples. Syntheses of four fluorescein-labelled T-2 or HT-2 toxin tracers were carried out and their binding response with seven monoclonal antibodies was evaluated. The most sensitive antibody-tracer combination was obtained by using an HT-2-specific antibody and a fluorescein-HT-2 tracer. The developed competitive FP immunoassay in solution showed high cross-reactivity for T-2 toxin (CR% = 100%) while a very low CR% for neosolaniol (0.12%) and no cross-reactivity with other mycotoxins frequently occurring in wheat. A rapid extraction procedure using 90% methanol was applied to wheat samples prior to FP immunoassay. The average recovery from spiked wheat samples (50 to 200 μg kg(-1)) was 96% with relative standard deviation generally lower than 8%. A limit of detection of 8 μg kg(-1) for the combined toxins was determined. Comparative analyses of 45 naturally contaminated and spiked wheat samples by both the FP immunoassay and high-performance liquid chromatography/immunoaffinity clean-up showed a good correlation (r = 0.964). These results, combined with the rapidity (10 min) and simplicity of the assay, show that this method is suitable for high throughput screening as well as for quantitative determination of T-2 and HT-2 toxins in wheat.

Flash memories operating in space are subject at the same time to the progressive accumulation of total ionizing dose and to intrinsic aging phenomena. In this work we investigate latent Total Ionizing Dose (TID) effects in 41-nm NAND single level cells that do not display neither floating gate errors nor any apparent kind of degradation after exposure. Retention of irradiated cells is analyzed at room and high temperature as a function of total dose previously received. We found that FG cell retention at room temperature is practically unchanged after a total dose up to 30 krad(Si). On the contrary, TID exposure slightly worsens the cell retention time during high-temperature tests. We attribute this behavior to the removal of compensating electrons from the tunnel oxide at high temperature.

A liquid chromatographic method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn-based foods for infants and young children was subjected to an interlaboratory validation study involving 11 laboratories. Five blind duplicate sample pairs of each matrix were analyzed to establish the accuracy, repeatability, and reproducibility of the method. Mass fractions in the baby food samples ranged from 89.1 to 384.4 μg/kg FB1 and from 22.5 to 73.6 μg/kg FB2. The method involved a warm extraction with citrate phosphate buffer–methanol–acetonitrile (50 + 25 + 25, v/v/v), a cleanup through an immunoaffinity column, and an end-determination of fumonisins by LC after automated precolumn derivatization with-o-phthaldialdehyde reagent. RSDs for within- laboratory repeatability (RSDr) ranged from 6.8 to 23.5% for FB1 and 7.6 to 22.9% for FB2. RSDs for between-laboratory reproducibility (RSDR) ranged from 15.4 to 26.2% for FB1 and 21.6 to 36.3% for FB2. Mean FB1 recoveries from baby foods spiked at 100.0 and 250.0 μg/kg were 89 and 96%, respectively; for FB2 spiked foods at 25.0 and 62.5 μg/kg recoveries were 90 and 85%, respectively. HorRat values ranged from 0.8 to 1.2 for FB1, whereas for FB2 they ranged from 0.9 to 1.4 when calculated according to Horwitz, and from 1.0 to 1.7 when calculated according to Thompson, indicating an acceptable among- laboratory precision for all matrixes (HorRat values

A TaqMan and a SYBR Green real time PCR (rt-PCR) were developed for the reliable identification and quantitative detection of Staphylococcus (S.) aureus strains harbouring the enterotoxin gene cluster (egc) regardless of its variants. Both approaches revealed 100% specificity against a panel of 70 reference strains, including 29 clinical and foodborne S. aureus strains harbouring all the egc variants to date known, 4 egc⁻S. aureus strains and 37 strains of phylogenetically closely and distantly related species. Standard curves made by 10 fold dilutions of either genomic DNA or cells from an egc(+)S. aureus log-phase broth culture showed a good linearity of response (R²≥0.993) for six orders of magnitude, with about 100% relative accuracy and a low inter-assay variability (CV≤3.02). The overall limit of quantification (LOQ) for both rt-PCR assays (about 100% PCR efficiency; running time 30 min) was 10 cfu or 10 genome equivalents per reaction mixture although 1 cfu or 1 genome equivalent was detected with a 33.33% probability. These performances were confirmed in raw milk artificially contaminated with log-phase broth cultures of either a single egc(+)S. aureus strain or a mixture of S. aureus strains harbouring all the egc variants to date known. Similar results were also obtained with a raw milk based standard curve of the S. aureus egc(+) mixture in the presence of 10⁶ cfu/mL of egc⁻S. aureus strains harbouring some of the commonest enterotoxin genes associated to the staphylococcal food poisoning. Nonetheless, the TaqMan based approach resulted in a lower sensitivity (LOQ=100 cfu equivalents per reaction mixture) than the SYBR Green based assay (LOQ=10 cfu equivalents per reaction mixture). When applied to real milk samples, both PCR assays provided a good response with 100% diagnostic specificity and 96-107% relative accuracy, as compared to conventional culture-based PCR approaches. Due to the high specificity, the wide dynamic range of detection and the high sensitivity demonstrated even in a complex and potentially highly contaminated raw milk matrix, the SYBR Green rt-PCR assay is a useful diagnostic tool for quick, high throughput and reliable routine screening of egc(+)S. aureus isolates. Moreover, the SYBR Green based quantitative detection of these pathogens in raw milk could remarkably contribute to clarify their actual role in staphylococcal food poisoning and other clinical syndromes associated with the consumption of milk and milk-based products.

International audience; The potential risk of exposure to fumonisin B2 (FB2 ) in the grape-wine chain has been recently pointed out after reporting Aspergillus niger in grapes and its ability to produce FB2 and FB4. The occurrence of these two fumonisins in wine was investigated by LC/MS/MS in fifty-one market samples (45 red, 5 white and one rosè wine) produced in various Italian regions. Nine samples of red wine were found contaminated by fumonisin B2 at levels ranging from 0.4 to 2.4 ng/mL, while FB4 was not detected in any of the tested samples. This is the first report on the natural occurrence of FB2 in wine indicating that, although al low levels, there is a real risk of FB2 exposure for the wine-consumer.

Electronic chips working in the space environment are constantly subject to both single event and total ionizing dose effects. To emulate this scenario for Flash memories, we tested under heavy ions floating gate cells, previously irradiated with x-rays, without performing any erase and program operation in between the two exposures. We observed an increase in the heavy-ion upset cross section in the devices that were submitted to TID irradiations, especially at low LETs. This effect is attributed to the combination of the threshold voltage shifts induced by heavy ions and x-rays. Implications for the hardness assurance of Flash memories are discussed.

This paper presents a detailed experimental investigation of the cycling-induced threshold voltage instability of deca-nanometer NAND Flash arrays, focusing on its dependence on cycling time and temperature. When the array is brought to a programmed state after cycling, instability mainly shows up as a negative shift of its threshold voltage cumulative distribution, increasing with time and resulting from partial recovery of cell damage created in the previous cycling period. The threshold voltage loss displays a strong dependence not only on the tunnel oxide electric field during retention, but also on the cycling conditions. In particular, performing cycling over a longer time interval or at higher temperatures delays the threshold voltage transients on the logarithmic time axis. The delay factor is studied as a function of the cycling duration and temperature on 60 and 41 nm technologies, extracting the parameter values required for a universal damage-recovery metric for NAND.

A method for the determination of fumonisin B1 (FB1) and B2 (FB2) in different commercial maize-based products for infants and young children was developed and tested in a limited validation study involving 3 laboratories. The method used extraction at 55 °C with an acidic mixture of methanol-acetonitrile-phosphate/citrate buffer, clean-up through immunoaffinity column and fumonisin determination by high performance liquid chromatography with automated pre-column derivatisation with o-phthaldialdehyde. Recovery experiments were performed at five spiking levels in the ranges of 80-800 µg/kg FB1 and 20-200 µg/kg FB2. Mean recoveries ranged from 83 to 97% for FB1 and from 61 to 78% for FB2. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 5 to 12% for FB1 and from 8 to 13% for FB2, whereas relative standard deviation for between-laboratory reproducibility (RSDR) ranged from 6 to 10% for FB1 and from 9 to 16% for FB2. The limit of quantification of the method (signal to noise ratio of 6) was 2.8 µg/kg for FB1 and 2.2 µg/kg for FB2. Fumonisins were found in 6 out of 19 maize-based baby foods obtained from the Italian retail market at levels up to 53 µg/kg.

We investigate atmospheric neutron effects on floating gate cells in MLC NAND Flash memories. Loss of information is shown to occur especially at the highest program levels, but to an extent that does not challenge current error correction capabilities. We discuss the physical mechanisms and analyze scaling trends, which show a rapid increase in sensitivity for decreasing feature size. A large spread in the cross section is visible from vendor to vendor for comparable feature size. © 2010 IEEE.

The effectiveness of seven phenolic compounds (esculetin, ferulic acid, quercetin, resveratrol, scopoletin, scoparone and umbelliferone) in controlling Penicillium expansum growth and patulin accumulation was evaluated by both in vitro and in vivo studies. The in vitro screening showed that quercetin and umbelliferone were the most effective compounds in controlling Penicillium growth and patulin accumulation, respectively. Quercetin and umbelliferone, resulted to be effective also in the in vivo screening, were further tested (alone and in combination) on Granny Smith and Golden Delicious apples. The efficacy in controlling Penicillium growth was better expressed on Golden Delicious than on Granny Smith apples, with quercetin providing a better control of both incidence of decay and disease severity as compared to umbelliferone. Both compounds exerted a considerable control of patulin accumulation on the two apple cultivars. Quercetin and umbelliferone can be considered as natural compounds to be used as alternative strategy to chemical fungicides in postharvest control of P. expansum infections on apples.