Habitat loss is the primary driver of biodiversity decline worldwide, but the effects of fragmentation (the spatial arrangement of remaining habitat) are debated. We tested the hypothesis that forest ...fragmentation sensitivity-affected by avoidance of habitat edges-should be driven by historical exposure to, and therefore species' evolutionary responses to disturbance. Using a database containing 73 datasets collected worldwide (encompassing 4489 animal species), we found that the proportion of fragmentation-sensitive species was nearly three times as high in regions with low rates of historical disturbance compared with regions with high rates of disturbance (i.e., fires, glaciation, hurricanes, and deforestation). These disturbances coincide with a latitudinal gradient in which sensitivity increases sixfold at low versus high latitudes. We conclude that conservation efforts to limit edges created by fragmentation will be most important in the world's tropical forests.
The fragmentation functions for a c or b¯ quark to a Bc or Bc* meson are derived up to QCD next-to-leading order. They are further computed numerically and presented precisely in figures. In order to ...reach a higher accuracy, we also try to properly use them to estimate Bc and Bc* production at a Z factory (an e+e− collider running at the energy of the Z-boson pole).
Codeine, a 3-methylmorphine, and other related opioids have been implicated in androgen suppression, although the associated mechanisms remain unclear.
Therefore, the objective of the current study ...was to elucidate the in vivo molecular mechanisms underlying codeine-induced androgen suppression.
This study made use of twenty-one healthy male rabbits, distributed into three groups randomly, control and codeine-treated groups. The control had 1ml of normal saline daily p.o. The codeine-treated groups received either 4mg/kg b.w of codeine or 10mg/kg b.w of codeine p.o. for six weeks. Reproductive hormonal profile, testicular weight, testicular enzymes, oxidative and inflammatory parameters, testicular DNA fragmentation, histological examination and apoptosis marker were evaluated to examine the effects of codeine use.
Oral administration of codeine resulted in testicular atrophy and alterations in testicular histomorphology, elevated testicular enzymes, and suppression of circulatory and intra-testicular testosterone. These changes were associated with a marked rise in oxidative markers and decline in the activities of testicular enzymatic antioxidants, as well as oxidative DNA damage, inflammatory response, testicular DNA fragmentation, and caspase-dependent apoptosis (p<0.05).
In conclusion, chronic codeine use resulted in testicular degeneration and testosterone suppression, which is attributable to TNF-α/nitric oxide-/oxidative stress-mediated caspase-dependent apoptotic testicular cell death and loss of testicular function.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
While habitat loss is a major threat to species, the effects of habitat fragmentation independent of habitat loss (fragmentation per se) are debated. Metapopulation studies often assert negative ...fragmentation effects, but they do not measure fragmentation per se. We evaluate the effects of fragmentation per se (patch density) across 20 years of patch occupancy patterns of the Åland Islands Glanville fritillary butterfly, Finland, a famous model system in metapopulation studies. Fragmentation per se had mainly positive effects on patch occupancy, the proportion of years occupied per patch, and patch colonization, and negative effects on patch extinction. These results suggest that fragmentation per se does not threaten persistence of the Åland Islands Glanville fritillary butterfly. Our results support the growing body of research challenging the paradigm that habitat fragmentation per se is mostly negative for species, highlighting the value of small patches for species conservation.
We revisit the recursive model for the fragmentation of polarized quarks based on the string +3P0 mechanism of qq¯ pair creation. We make a different choice for one input function of the model that ...simplifies the implementation in a Monte Carlo program. No new parameters are introduced, and the relevant results are the same apart from the suppression of the spin-independent correlations between suc2cessive quarks. The advantage of the present version is that it allows us to study analytically the preservation of positivity bounds and it is more suitable for an interface with external event generators like PYTHIA. The theoretical aspects and the simulation results obtained with a stand alone program are discussed in detail and compared with those of the previous version of the model.
The need to design an optimally distributed database is increasingly important with the growth of information technology and computer networks. However, designing a distributed database is an ...extremely complex process due to a large number of geographically distributed sites and database relations. Moreover, decreasing communication costs and query response time should be taken into consideration. There are three main techniques applied to design a distributed database, namely Fragmentation, Data allocation, and Replication. It is notable that these techniques are often treated separately and rarely processed together. Some available allocation methods are applied regardless of how the fragmentation technique is performed or replication process is adopted. In contrast, other fragmentation techniques do not consider the allocation or the replication techniques. Therefore, the first and foremost step for designing an optimal database is to develop a comprehensive understanding of the current fragmentation, replication, and allocation techniques and their disadvantages. This article presents an attempt to fulfill this step by proposing a comprehensive taxonomy of the available fragmentation and allocation techniques in distributed database design. The article also discusses some case studies of these techniques for a deeper understanding of its achievements and limitations.
Triptolide being an active ingredient of Chinese herbal plant
Tripterygium wilfordii
Hook f. has severe hepatotoxicity. Previous studies from our lab reported triptolide-induced mitochondrial ...toxicity in hepatocytes. However, biomolecular mechanisms involved in triptolide-induced mitochondrial dysfunction are not yet entirely clear. We explored the connection between mitochondrial fragmentation and mitophagy in triptolide-induced hepatotoxicity. Triptolide caused an increase in ROS production, a decrease in mitochondrial depolarization, a diminution of ATP generation, a decline in mitochondrial DNA copy number, mitochondrial fragmentation, and disturbance in mitochondrial dynamics in a concentration-dependent manner in L02 cells. Disturbance in mitochondrial dynamics was due to an increased expression of Drp1 fission protein in vitro and in vivo. L02 cells exhibited an increase in the colocalization of lysosomes with mitochondria and autophagosomes with mitochondria in triptolide treated group as compared to control group which was inhibited by Mdivi-1. Transmission electron micrographs of rat liver tissues treated with triptolide (400 μg/kg) revealed activation of mitophagy which was prevented by Mdivi-1 co-treatment. Taken together, our results showed that mitochondrial fission-associated mitophagy is a novel mechanism involved in triptolide-induced hepatotoxicity. For the alleviation of triptolide-induced hepatotoxicity, mitochondrial fission and mitochondrial autophagy signaling pathway can be targeted as a new therapeutic strategy.
Graphical abstract
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We compute leading-power fragmentation corrections to J/psi production at the Tevatron and the LHC. We find that, when these corrections are combined with perturbative corrections through ...next-to-leading order in the strong coupling constant alpha sub(s) we obtain a good fit to high-p sub(T)cross section data from the CDF and CMS Collaborations. The fitted long-distance matrix elements lead to predictions of near-zero J/psi polarization in the helicity frame at large p sub(T)
Alkali and alkaline earth metal adducts of a branched glycan, XXXG, were analyzed with helium charge transfer dissociation (He‐CTD) and low‐energy collision‐induced dissociation (LE‐CID) to ...investigate if metalation would impact the type of fragments generated and the structural characterization of the analyte. The studied adducts included 1+ and 2+ precursors involving one or more of the cations: H+, Na+, K+, Ca2+, and Mg2+. Regardless of the metal adduct, He‐CTD generated abundant and numerous glycosidic and cross‐ring cleavages that were structurally informative and able to identify the 1,4‐linkage and 1,6‐branching patterns. In contrast, the LE‐CID spectra mainly contained glycosidic cleavages, consecutive fragments, and numerous neutral losses, which complicated spectral interpretation. LE‐CID of M + K + H2+ and M + Na+ precursors generated a few cross‐ring cleavages, but they were not sufficient to identify the 1,4‐linkage and 1,6‐branching pattern of the XXXG xyloglucan. He‐CTD predominantly generated 1+ fragments from 1+ precursors and 2+ product ions from 2+ precursors, although both LE‐CID and He‐CTD were able to generate 1+ product ions from 2+ adducts of magnesium and calcium. The singly charged fragments derive from the loss of H+ from the metalated product ions and the formation of a protonated complementary product ion; such observations are similar to previous reports for magnesium and calcium salts undergoing electron capture dissociation (ECD) activation. However, during He‐CTD, the M + Mg2+ precursor generated more singly charged product ions than M + Ca2+, either because Mg has a higher second ionization potential than Ca or because of conformational differences and the locations of the charging adducts during fragmentation. He‐CTD of the M + 2Na2+ and the M + 2 K2+ precursors generated singly charged product ions from the loss of a sodium ion and potassium ion, respectively. In summary, although the metal ions influence the mass and charge state of the observed product ions, the metal ions had a negligible effect on the types of cross‐ring cleavages observed.
We herein summarise the evidence concerning the impact of sperm DNA fragmentation in various clinical infertility scenarios and the advances on sperm DNA fragmentation tests. The collected evidence ...was used to formulate 41 recommendations. Of these, 13 recommendations concern technical aspects of sperm DNA fragmentation testing, including pre‐analytical information, clinical thresholds and interpretation of results. The remaining 28 recommendations relate to indications for sperm DNA fragmentation testing and clinical management. Clinical scenarios like varicocele, unexplained infertility, idiopathic infertility, recurrent pregnancy loss, intrauterine insemination, in vitro fertilisation/intracytoplasmic sperm injection, fertility counselling for men with infertility risk factors and sperm cryopreservation have been contemplated. The bulk evidence supporting the recommendations has increased in recent years, but it is still of moderate to low quality. This guideline provides clinicians with advice on best practices in sperm DNA fragmentation testing. Also, recommendations are provided on possible management strategies to overcome infertility related to sperm DNA fragmentation, based on the best available evidence. Lastly, we identified gaps in knowledge and opportunities for research and elaborated a list of recommendations to stimulate further investigation.
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