34 research outputs found
HPLC Analysis of Phenolic Compounds and Antioxidant Activity of Ribes Fruit Leaves
Berry fruit leaves are recognized as potential medicaments which are rich
in different phenolic compounds, and have been used in folk medicine for centuries. In
order to evaluate phenol composition of fruit leaves from red currant (Ribes rubrum)
and black currant (Ribes nigrum) species were subjected to the spectrophotometric and
HPLC analysis. The antioxidant activity was estimated using DPPH free radical
scavenging assay. Flavonols, flavan-3-ols and phenolic acids were the main phenol
classes found in the investigated leaf extracts. Investigated extracts showed significant
antioxidant activity and a correlation with total phenol content. Ribes leaf extracts, rich
in phenolic content, with significant antioxidant activity, can be used as medical
supplements
Polyphenols and Antioxidant Activity of Different Vinegrape Leaves
The volume of the grape waste produced directly relates to the volume of
grapes pressed and in turn depends on the specific climatic conditions of the relevant
vintage. The aim of this work is to evaluate vinegrape leaves as a potential source of
natural antioxidants – polyphenols for their possible use as dietary supplement or food
antioxidants. To this purpose antioxidant activity and contents of phenolic compounds
of the leaves extracts of five grape varieties of Vitis vinifera L (Vranac, Prokupac,
Merlot, Gamay and Italian Rizling), grown in southern Serbia were investigated. The
analysis show high content of polyphenols reflecting their high antioxidant activity (R2
= 0.9819, p<0.01). According to the obtained results, the leaves extracts, can be
considered rich natural source of phenolic compounds with good antioxidant properties
Prediction of Solar Particle Events with SRAM-Based Soft Error Rate Monitor and Supervised Machine Learning
This work introduces an embedded approach for the prediction of Solar Particle Events (SPEs) in space applications by combining the real-time Soft Error Rate (SER) measurement with SRAM-based detector and the offline trained machine learning model. The proposed approach is intended for the self-adaptive fault-tolerant multiprocessing systems employed in space applications. With respect to the state-of-the-art, our solution allows for predicting the SER 1 h in advance and fine-grained hourly tracking of SER variations during SPEs as well as under normal conditions. Therefore, the target system can activate the appropriate mechanisms for radiation hardening before the onset of high radiation levels. Based on the comparison of five different machine learning algorithms trained with the public space flux database, the preliminary results indicate that the best prediction accuracy is achieved with the recurrent neural network (RNN) with long short-term memory (LSTM)
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PS-BBICS: Pulse stretching bulk built-in current sensor for on-chip measurement of single event transients
The bulk built-in current sensor (BBICS) is a cost-effective solution for detection of energetic particle strikes in integrated circuits. With an appropriate number of BBICSs distributed across the chip, the soft error locations can be identified, and the dynamic fault-tolerant mechanisms can be activated locally to correct the soft errors in the affected logic. In this work, we introduce a pulse stretching BBICS (PS-BBICS) constructed by connecting a standard BBICS and a custom-designed pulse stretching cell. The aim of PS-BBICS is to enable the on-chip measurement of the single event transient (SET) pulse width, allowing to detect the linear energy transfer (LET) of incident particles, and thus assess more accurately the radiation conditions. Based on Spectre simulations, we have shown that for the LET from 1 to 100 MeV cm2 mg−1, the SET pulse width detected by PS-BBICS varies by 620–800 ps. The threshold LET of PS-BBICS increases linearly with the number of monitored inverters, and it is around 1.7 MeV cm2 mg−1 for ten monitored inverters. On the other hand, the SET pulse width is independent of the number of monitored inverters for LET > 4 MeV cm2 mg−1. It was shown that supply voltage, temperature and process variations have strong impact on the response of PS-BBICS
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Design and Evaluation of Radiation-Hardened Standard Cell Flip-Flops
Use of a standard non-rad-hard digital cell library in the rad-hard design can be a cost-effective solution for space applications. In this paper we demonstrate how a standard non-rad-hard flip-flop, as one of the most vulnerable digital cells, can be converted into a rad-hard flip-flop without modifying its internal structure. We present five variants of a Triple Modular Redundancy (TMR) flip-flop: baseline TMR flip-flop, latch-based TMR flip-flop, True-Single Phase Clock (TSPC) TMR flip-flop, scannable TMR flip-flop and self-correcting TMR flip-flop. For all variants, the multi-bit upsets have been addressed by applying special placement constraints, while the Single Event Transient (SET) mitigation was achieved through the usage of customized SET filters and selection of optimal inverter sizes for the clock and reset trees. The proposed flip-flop variants feature differing performance, thus enabling to choose the optimal solution for every sensitive node in the circuit, according to the predefined design constraints. Several flip-flop designs have been validated on IHP’s 130nm BiCMOS process, by irradiation of custom-designed shift registers. It has been shown that the proposed TMR flip-flops are robust to soft errors with a threshold Linear Energy Transfer (LET) from ( 32.4 (MeV⋅cm2/mg) ) to ( 62.5 (MeV⋅cm2/mg) ), depending on the variant
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Analysis of Single Event Transient Effects in Standard Delay Cells Based on Decoupling Capacitors
Single Event Transients (SETs), i.e., voltage glitches induced in combinational logic as a result of the passage of energetic particles, represent an increasingly critical reliability threat for modern complementary metal oxide semiconductor (CMOS) integrated circuits (ICs) employed in space missions. In rad-hard ICs implemented with standard digital cells, special design techniques should be applied to reduce the Soft Error Rate (SER) due to SETs. To this end, it is essential to consider the SET robustness of individual standard cells. Among the wide range of logic cells available in standard cell libraries, the standard delay cells (SDCs) implemented with the skew-sized inverters are exceptionally vulnerable to SETs. Namely, the SET pulses induced in these cells may be hundreds of picoseconds longer than those in other standard cells. In this work, an alternative design of a SDC based on two inverters and two decoupling capacitors is introduced. Electrical simulations have shown that the propagation delay and SET robustness of the proposed delay cell are strongly influenced by the transistor sizes and supply voltage, while the impact of temperature is moderate. The proposed design is more tolerant to SETs than the SDCs with skew-sized inverters, and occupies less area compared to the hardening configurations based on partial and complete duplication. Due to the low transistor count (only six transistors), the proposed delay cell could also be used as a SET filter
Opis przypadku — występujący rodzinnie wewnątrzczaszkowo germinoma
Background. Intracranial germinomas (ICG) are uncommon brain neoplasms with extremely rare familial occurance. Since ICG invades hypothalamus and/or pituitary, the endocrine dysfunction is one of the common determinants of these tumors.
We presented two brothers with the history of ICG. Patient 1 is a 25-year-old male who had been suffering from the weakness of the right half of his body at the age of 18. Cranial MRI revealed mass lesion in the left thalamus. He underwent neurosurgery, tumor was removed completely. Histopathological (HP) and immunohistochemical analyses verified the diagnosis of pure germinoma. He experienced complete remission of the tumor after a radiation therapy. At the age of 22 the diagnosis of isolated growth hormone deficiency (IGHD) was established and GH replacement was initiated. Patient 2 is a 20-year old boy who was presented with diabetes insipidus at the age of 12. MRI detected tumor in the third ventricle and pineal region. After the endoscopic tumor biopsy the HP diagnosis was pure germinoma. He received chemotherapy followed by radiotherapy, and treated with GH during childhood. At the age of 18 GH replacement was reintroduced. A six month follow-up during the next two years in both brothers demonstrated the IGF1 normalization with no MRI signs of tumor recurrence.
Conclusion. To the best of our knowledge so far, only six reports have been published related to familial ICG. The presented two brothers are the first report of familial ICG case outside of Japan. They are treated successfully with GH therapy in adult period.
Wstęp: Rozrodczaki wewnątrzczaszkowe (intracranial germinomas, ICG) to rzadkie nowotwory mózgu, a szczególnie rzadko stwierdza się ich występowanie rodzinne. W związku z tym, że ICG zajmuje podwzgórze i/lub przysadkę mózgową, zaburzenia endokrynologiczne są jednym z najczęstszych wyznaczników obecności tych guzów.
W pracy przedstawiono dwóch braci z ICG. Pacjent 1 to 25-letni mężczyzna, u którego w wieku 18 lat wystąpiło osłabienie mięśni po lewej stronie ciała. Badanie metodą rezonansu magnetycznego (MRI) czaszki ujawniło masę w lewym wzgórzu. Chorego poddano zabiegowi neurochirurgicznemu, podczas którego guz został całkowicie usunięty. Badania histopatologiczne i immunohistochemiczne potwierdziły rozpoznanie czystej postaci rozrodczaka. Po radioterapii nastąpiła całkowita remisja guza. W wieku 22 lat u chorego zdiagnozowano izolowany niedobór hormonu wzrostu (isolated growth hormone deficiency, IGHD) i wdrożono terapię zastępczą hormonem wzrostu (growth hormone, GH). Genetyczna analiza molekularna tkanki guza wykazała mutację w eksonie 2 w genie KRAS. Pacjent 2 to 20-letni mężczyzna, u którego w wieku 12 lat stwierdzono moczówkę prostą. W badaniu MRI wykryto guz w okolicy trzeciej komory i szyszynki. Po ocenie histopatologicznej materiału pobranego za pomocą biopsji endoskopowej postawiono diagnozę czystego rozrodczaka. U chorego zastosowano chemioterapię, a następnie radioterapię, a także podawano GH w okresie dzieciństwa. W wieku 18 lat u chorego wznowiono terapię GH. Sześciomiesięczna obserwacja obu braci w następnych 2 latach wykazała normalizację IGF1 przy braku objawów nawrotu guza w badaniu MRI.
Wnioski: Według najlepszej wiedzy autorów dotychczas opublikowano 6 doniesień na temat rodzinnego występowania ICG. Przedstawieni w niniejszej pracy bracia są pierwszym opisanym przypadkiem rodzinnego ICG poza Japonią. W okresie dorosłym chorzy są leczeni GH z dobrym skutkiem