CHARACTERISTIC FEATURES AND MECHANISMS OF NUCLEAR FRAGMENTATION

1993 ◽  
Vol 02 (04) ◽  
pp. 679-730 ◽  
Author(s):  
J. RICHERT

Nuclear fragmentation at high energy shows characteristic features which may serve as a guideline for the description and understanding of the mechanisms leading to experimentally observed mass or charge distributions. Results obtained by means of different models proposed in the past are analysed and discussed. Using the available information, recent efforts made in order to find the clue of the mechanisms which lead to the disassembly of nuclei are presented.

2019 ◽  
Vol 7 ◽  
pp. 163
Author(s):  
M. Kokkoris ◽  
H. Huber ◽  
S. Kossionides ◽  
T. Paradellis ◽  
Ch. Zarkadas ◽  
...  

Several experiments have been carried out in the past in order to examine the impact of medium and heavy ions in crystals in the MeV range, which is of particular interest in high energy implantations. In the present work, the gradual amorphisation of simple crystals such as Si (100), Ge (100) and W (100) when irradiated with 18 MeV 1 6 0 in a random direction is being studied using the progressive change of channeling parameters, up to a maximum dose of approximately 1Ί01 6 par tides/en*2. The results are compared to the ones present in literature and an attempt is made in order to explain the peculiarities of the experimental spectra.


1995 ◽  
Vol 73 (5-6) ◽  
pp. 365-368 ◽  
Author(s):  
Fu-Hu Liu ◽  
Han-Cheng Sun

The conditional moments of the charge distributions of the projectile fragments in O and S fragmentation are obtained using the partition method. Thus, the logarithmic correlations between the conditional moments can be observed. The electromagnetic dissociations are similar to the correlation behaviour of nuclear reactions. This is illustrated by the correlation behaviour of the oxygen nuclei, which are in agreement with that of the sulphur nuclei. The calculated results correspond to the experimental data of 3.7 and 200 GeV N−1 O–Em and 200 GeV N−1 S–Em interactions.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luis I. Quiroz ◽  
Luis A. Buatois ◽  
Koji Seike ◽  
M. Gabriela Mángano ◽  
Carlos Jaramillo ◽  
...  

AbstractThe distribution of trace-making organisms in coastal settings is largely controlled by changes in physicochemical parameters, which in turn are a response to different climatic and oceanographic conditions. The trace fossil Macaronichnus and its modern producers are typical of high-energy, siliciclastic foreshore sands in intermediate- to high-latitude settings characterized by cold-water conditions. However, it has been found in Miocene Caribbean deposits of Venezuela, prompting the hypothesis that upwelling of cold, nutrient-rich waters rather than latitude was the main control of its distribution. To test this hypothesis that was solely based on the fossil record, several trenches and sediment peels were made in two high-energy sand beaches having different oceanographic conditions along the Pacific and Caribbean coasts of the Central American Isthmus. As predicted, the burrows were found only in the highly productive waters of the Pacific coast of Costa Rica in connection with upwelling, while they were absent from the warm, oligotrophic waters of the Caribbean coast of Panama. This finding demonstrates that sometimes the past may be a key to the present, providing one of the few documented examples of reverse uniformitarianism.


1973 ◽  
Vol 12 (2) ◽  
pp. 181-188
Author(s):  
Rafiq Ahmad

Like nations and civilizations, sciences also pass through period of crises when established theories are overthrown by the unpredictable behaviour of events. Economics is passing through such a crisis. The challenge thrown by the Great Depression of early 1930s took a decade before Keynes re-established the supremacy of economics. But this supremacy has again been upset by the crisis of poverty in the vast under-developed world which attained political independence after the Second World War. Poverty had always existed but never before had it been of such concern to economists as during the past twenty five years or so. Economic literature dealing with this problem has piled up but so have the agonies of poverty. No plausible and well-integrated theory of economic development or under-development has emerged so far, though brilliant advances have been made in isolated directions.


Author(s):  
Rocco J. Rotello ◽  
Timothy D. Veenstra

: In the current omics-age of research, major developments have been made in technologies that attempt to survey the entire repertoire of genes, transcripts, proteins, and metabolites present within a cell. While genomics has led to a dramatic increase in our understanding of such things as disease morphology and how organisms respond to medications, it is critical to obtain information at the proteome level since proteins carry out most of the functions within the cell. The primary tool for obtaining proteome-wide information on proteins within the cell is mass spectrometry (MS). While it has historically been associated with the protein identification, developments over the past couple of decades have made MS a robust technology for protein quantitation as well. Identifying quantitative changes in proteomes is complicated by its dynamic nature and the inability of any technique to guarantee complete coverage of every protein within a proteome sample. Fortunately, the combined development of sample preparation and MS methods have made it capable to quantitatively compare many thousands of proteins obtained from cells and organisms.


1981 ◽  
Vol 46 (9) ◽  
pp. 2068-2075 ◽  
Author(s):  
Stanislav Böhm ◽  
Josef Kuthan

Results of ab initio MO calculations of the dihydropyridine molecules I-V are confronted with analogous CNDO/2 and MINDO/3 calculations. The molecular energies calculated by means of the 4-31 G base predict the 6pi-electron isomers I and II to be the most stable dihydropyridine forms in contrast to the STO-3G and CNDO/2 data preferring the 4pi-electron isomers III-V. The charge distributions calculated non-empirically and semiempirically show different characteristic features.


Author(s):  
John Hunsley ◽  
Eric J. Mash

Evidence-based assessment relies on research and theory to inform the selection of constructs to be assessed for a specific assessment purpose, the methods and measures to be used in the assessment, and the manner in which the assessment process unfolds. An evidence-based approach to clinical assessment necessitates the recognition that, even when evidence-based instruments are used, the assessment process is a decision-making task in which hypotheses must be iteratively formulated and tested. In this chapter, we review (a) the progress that has been made in developing an evidence-based approach to clinical assessment in the past decade and (b) the many challenges that lie ahead if clinical assessment is to be truly evidence-based.


2021 ◽  
pp. 088506662199232
Author(s):  
Xiaojuan Zhang ◽  
Xin Li

Septic shock with multiple organ failure is a devastating situation in clinical settings. Through the past decades, much progress has been made in the management of sepsis and its underlying pathogenesis, but a highly effective therapeutic has not been developed. Recently, macromolecules such as histones have been targeted in the treatment of sepsis. Histones primarily function as chromosomal organizers to pack DNA and regulate its transcription through epigenetic mechanisms. However, a growing body of research has shown that histone family members can also exert cellular toxicity once they relocate from the nucleus into the extracellular space. Heparin, a commonly used anti-coagulant, has been shown to possess life-saving capabilities for septic patients, but the potential interplay between heparin and extracellular histones has not been investigated. In this review, we summarize the pathogenic roles of extracellular histones and the therapeutic roles of heparin in the development and management of sepsis and septic shock.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1544
Author(s):  
Jet Yin Boey ◽  
Lydia Mohamad ◽  
Yong Sen Khok ◽  
Guan Seng Tay ◽  
Siti Baidurah

Overconsumption of plastic goods and improper handling of petroleum-derived plastic waste have brought a plethora of negative impacts to the environment, ecosystem and human health due to its recalcitrance to degradation. These drawbacks become the main driving force behind finding biopolymers with the degradable properties. With the advancement in biopolymer research, polyhydroxyalkanoate (PHA) and poly(lacyic acid) (PLA) and its composites have been alluded to as a potential alternative to replace the petrochemical counterpart. This review highlights the current synthesis process and application of PHAs and PLA and its composites for food packaging materials and coatings. These biopolymers can be further ameliorated to enhance their applicability and are discussed by including the current commercially available packaging products. Factors influencing biodegradation are outlined in the latter part of this review. The main aim of this review article is to organize the scattered available information on various aspects of PHAs and PLA, and its composites for packaging application purposes. It is evident from a literature survey of about 140 recently published papers from the past 15 years that PLA and PHA show excellent physical properties as potential food packaging materials.


Author(s):  
Zening Lin ◽  
Tao Jiang ◽  
Jianzhong Shang

Abstract In the past few decades, robotics research has witnessed an increasingly high interest in miniaturized, intelligent, and integrated robots. The imperative component of a robot is the actuator that determines its performance. Although traditional rigid drives such as motors and gas engines have shown great prevalence in most macroscale circumstances, the reduction of these drives to the millimeter or even lower scale results in a significant increase in manufacturing difficulty accompanied by a remarkable performance decline. Biohybrid robots driven by living cells can be a potential solution to overcome these drawbacks by benefiting from the intrinsic microscale self-assembly of living tissues and high energy efficiency, which, among other unprecedented properties, also feature flexibility, self-repair, and even multiple degrees of freedom. This paper systematically reviews the development of biohybrid robots. First, the development of biological flexible drivers is introduced while emphasizing on their advantages over traditional drivers. Second, up-to-date works regarding biohybrid robots are reviewed in detail from three aspects: biological driving sources, actuator materials, and structures with associated control methodologies. Finally, the potential future applications and major challenges of biohybrid robots are explored. Graphic abstract


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