Changes in the relative abundances of coral taxa during recovery from disturbance may cause shifts in essential ecological processes on coral reefs. Coral cover can return to pre-disturbance levels ...(coral recovery) without the assemblage returning to its previous composition (i.e., without reassembly). The processes underlying such changes are not well understood due to a scarcity of long-term studies with sufficient taxonomic resolution. We assessed the trajectories and time frames for coral recovery and reassembly of coral communities following disturbances, using modeled trajectories based on data from a broad spatial and temporal monitoring program. We studied coral communities at six reefs that suffered substantial coral loss and subsequently regained at least 50 % of their pre-disturbance coral cover. Five of the six communities regained their coral cover and the rates were remarkably consistent, taking 7–10 years. Four of the six communities reassembled to their pre-disturbance composition in 8–13 years. The coral communities at three of the reefs both regained coral cover and reassembled ten years. The trajectories of two communities suggested that they were unlikely to reassemble and the remaining community did not regain pre-disturbance coral cover. The communities that regained coral cover and reassembled had high relative abundance of tabulate
Acropora
spp. Coral communities of this composition appear likely to persist in a regime of pulse disturbances at intervals of ten years or more. Communities that failed to either regain coral cover or reassemble were in near-shore locations and had high relative abundance of
Porites
spp. and soft corals. Under current disturbance regimes, these communities are unlikely to re-establish their pre-disturbance community composition.
Eight novel carbohydrate-tethered trithiolato dinuclear ruthenium(II)-arene complexes were synthesized using CuAAC ‘click’ (Cu(I)-catalyzed azide-alkyne cycloaddition) reactions, and there in vitro ...activity against transgenic T. gondii tachyzoites constitutively expressing β-galactosidase (T. gondii β-gal) and in non-infected human foreskin fibroblasts, HFF, was determined at 0.1 and 1 µM. When evaluated at 1 µM, seven diruthenium-carbohydrate conjugates strongly impaired parasite proliferation by >90%, while HFF viability was retained at 50% or more, and they were further subjected to the half-maximal inhibitory concentration (IC50) measurement on T. gondii β-gal. Results revealed that the biological activity of the hybrids was influenced both by the nature of the carbohydrate (glucose vs. galactose) appended on ruthenium complex and the type/length of the linker between the two units. 23 and 26, two galactose-based diruthenium conjugates, exhibited low IC50 values and reduced effect on HFF viability when applied at 2.5 µM (23: IC50 = 0.032 µM/HFF viability 92% and 26: IC50 = 0.153 µM/HFF viability 97%). Remarkably, compounds 23 and 26 performed significantly better than the corresponding carbohydrate non-modified diruthenium complexes, showing that this type of conjugates are a promising approach for obtaining new antiparasitic compounds with reduced toxicity.
Physicochemical Study of a Metastable-State Photoacid Johns, Valentine K; Wang, Zhuozhi; Li, Xinxue ...
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory,
12/2013, Letnik:
117, Številka:
49
Journal Article
Recenzirano
A photoacid that possesses a metastable acidic state induced by visible light is studied. Previous work showed that this photoacid can reversibly produce a large pH change capable of controlling ...chemical reactions, altering material properties, and killing bacteria. In this work, we studied the relaxation kinetics of the metastable acidic state in different solvents including water, ethanol, and DMSO. In all of these solvents, the kinetic data can be fitted well to a second-order rate equation, which indicates that protonation is involved in the rate-limiting step. The rate constants in water, ethanol, and DMSO are 73, 1.6, and 0.034 M–1 s–1, respectively. The slow relaxation in DMSO allowed us to fully characterize the structure of the metastable acidic state using proton NMR. We also measured the quantum yield of the photoreaction, which is as high as 0.37.
Over the past decade, a large number of jet substructure observables have been proposed in the literature, and explored at the LHC experiments. Such observables attempt to utilize the internal ...structure of jets in order to distinguish those initiated by quarks, gluons, or by boosted heavy objects, such as top quarks and
W
bosons. This report, originating from and motivated by the BOOST2013 workshop, presents original particle-level studies that aim to improve our understanding of the relationships between jet substructure observables, their complementarity, and their dependence on the underlying jet properties, particularly the jet radius and jet transverse momentum. This is explored in the context of quark/gluon discrimination, boosted
W
boson tagging and boosted top quark tagging.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
► Unique investigation of leaf age and shade on six important compounds found in tea. ► Compounds analysed were l-theanine, caffeine, EGCG, EGC, EC, and ECG. ► First study of its type on ...Hawaiian-grown tea. ► Results show l-theanine and caffeine levels decrease with leaf age and catechin levels increase. ► Concentration of the catechin EGC increased up to 10-fold in moving from the bud to the second leaf.
This study showed the relationship between tea leaf age, bud and first two leaves, and shade levels, on the relative concentrations of six major compounds of tea leaf, namely l-theanine, caffeine, and the major tea catechins; (−)-epigallocatechin gallate (EGCG), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (−)-epicatechin gallate (ECG), all of which are reported to have positive effects on human health, as well as at the ferric reducing antioxidant power of bud and leaf extracts. The concentration of l-theanine and caffeine decreased as leaf age increased moving from bud to first and then second leaf, while the concentration of the four catechins increased from the bud to first and second leaves. In most cases this increase was generally relatively small but in the case of EGC it was 7 to 10-fold. Certain chemical components of freshly picked, minimally processed and essentially unoxidised tea may potentially be used as markers for age, quality, authenticity and area of growth.
Rates of return-to-work after stroke are low, yet work is known to positively impact people's wellbeing and overall health outcomes.
To understand return-to-work trajectories, barriers encountered, ...and resources that may be used to better support participants during early recovery and rehabilitation.
The experiences of 31 participants (aged 25-76 years) who had or had not returned to work after stroke were explored.
Interview data were analysed using reflexive thematic analysis methods within a broader realist research approach.
Participants identified an early need to explore a changed and changing occupational identity within a range of affirming environments, thereby ascertaining their return-to-work options early after stroke. The results articulate resources participants identified as most important for their occupational explorations. Theme 1 provides an overview of opportunities participants found helpful when exploring work options, while theme 2 explores fundamental principles for ensuring the provided opportunities were perceived as beneficial. Finally, theme 3 provides an overview of prioritized return-to-work service characteristics.
The range and severity of impairments experienced by people following stroke are broad, and therefore their return-to-work needs are diverse. However, all participants, irrespective of impairment, highlighted the need for early opportunities to explore their changed and changing occupational identity.
Background. The objective of this study was to determine if a chronic eccentric training intervention, i.e., negative work, could limit or even reverse sarcopenia and its related impairments and ...functional limitations. Is high-force eccentric training tolerable by elderly people and will it result in improved muscle size, strength, balance, and fall risk? Methods. 21 frail elderly subjects (mean age, 80 years) experienced 11 weeks of lower extremity resistance training. The experimental eccentric (ECC) group (\batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{n}\ {=}\ 11\) \end{document}) performed negative work while exercising on a high-force eccentric ergometer. The active “controls” performed traditional (TRAD) (\batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathit{n}\ {=}\ 10\) \end{document}) lower extremity resistance exercises (weight training). Muscle fiber cross-sectional area and strength, balance, stair descending abilities, and fall risk were assessed prior to and following this intervention. Results. All ECC subjects who started the negative work intervention completed the study and reported the training to be relatively effortless; they experienced minimal and transient muscle soreness. Both groups experienced a significant increase in muscle fiber cross-sectional area (\batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(ECC\ {=}\ 60{\%}\) \end{document}, \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(TRAD\ {=}\ 41{\%}\) \end{document}). Only the ECC group experienced significant improvements in strength (60%), balance (7%), and stair descent (21%) abilities. The timed up and go task improved in both groups, but only the ECC group went from a high to a low fall risk. Conclusions. These data demonstrate that lower extremity resistance exercise can improve muscle structure and function in those with limited exercise tolerance. The greater strength increase following negative work training resulted in improved balance, stair descent, and fall risk only in the ECC group. Because low energy cost is coupled to high force production with eccentric exercise, this intervention may be useful for a number of patients that are otherwise unable to achieve high muscle forces with traditional resistance exercise.
Rationale
Evidence suggests that differential rearing influences the function of a receptor subtype critical for maintaining glutamate homeostasis. Maintaining homeostatic glutamatergic function may ...be an important protector against drug abuse.
Objective
This study sought to determine if differential rearing influences the function of a receptor critical for glutamate homeostasis, which could in turn affect rates of amphetamine self-administration.
Methods
Rats were assigned to enriched (EC), isolated (IC), or standard (SC) conditions. After rearing for 30 days, rats were trained to lever press for sucrose reinforcement before the implantation of indwelling jugular catheters. After reaching stable responding for amphetamine (0.03 or 0.1 mg/kg/infusion), rats were injected with five doses (0, 0.3, 1.0, 3.0, and 5.0 mg/kg) of the mGluR
5
antagonist, 3-((2-methyl-1,3-thiazol-4-yl)ethynyl) pyridine hydrochloride (MTEP), 30 min before self-administration sessions. Following fixed-ratio (FR-1) testing, rats were administered identical doses of MTEP on a progressive-ratio (PR) reinforcement schedule.
Results
MTEP (3.0 mg/kg) attenuated FR-1 self-administration (0.03 mg/kg/infusion) in IC rats. MTEP also dose-dependently attenuated amphetamine self-administration (0.1 mg/kg/infusion) during FR-1 and PR sessions, with 5.0 mg/kg MTEP attenuating amphetamine self-administration in IC and SC rats and 3.0 mg/kg MTEP attenuating amphetamine self-administration in EC and SC rats. PR results also revealed that IC rats not treated with MTEP were more motivated to self-administer the higher dose of amphetamine.
Conclusions
These results suggest that the mGlu
5
receptor mediates differences in drug-taking behavior among differentially reared rats. Isolation also decreased sensitivity to MTEP, suggesting that environmental factors alter glutamate homeostasis which subsequently affects sensitivity and motivation to self-administer amphetamine.
Phosphatidic acid (PA) is emerging as an important lipid signalling molecule. In plants, it is implicated in various stress-signalling pathways and is formed in response to wounding, osmotic stress, ...cold stress, pathogen elicitors, Nod factors, ethylene and abscisic acid. How PA exerts its effects is still unknown, mainly because of the lack of characterized PA targets. In an approach to isolate such targets we have used PA-affinity chromatography. Several PA-binding proteins were present in the soluble fraction of tomato and Arabidopsis cells. Using mass spectrometric analysis, several of these proteins, including Hsp90, 14-3-3 proteins, an SnRK2 serine/threonine protein kinase and the PP2A regulatory subunit RCN1 could be identified. As an example, the binding of one major PA-binding protein, phosphoenolpyruvate carboxylase (PEPC), was characterized further. Competition experiments with different phospholipids confirmed specificity for PA. Hypo-osmotic treatment of the cells increased the amount of PEPC that bound the PA beads without increasing the absolute amount of PEPC. This suggests that PEPC's affinity for PA had increased. The work shows that PA-affinity chromatography/mass spectrometry is an effective way to isolate and identify PA-binding proteins from plants.
Controlled release of odorous molecules is the key to digital scent technology which will add another dimension to electronics. Photorelease is a cold mechanism that promises better temporal and ...spatial control than thermal release. Herein we report a novel material composed of an acid‐sensitive polymer carrying a fragrant aldehyde and a reversible metastable‐state photoacid. It releases the fragrant molecule under visible light, and stops releasing it after the light is turned off. A metastable‐state photoacid with a fast reverse‐reaction rate was developed to quickly stop the release after irradiation. Both the carrier polymer and the photoacid can be reused after all the fragrant molecules have been released. The material combines the advantages of visible‐light activity, fast on/off rate, easy preparation, and recyclability, and thus is promising for digital scent technology.
It makes scent: A material composed of an acid‐sensitive polymer and a reversible metastable‐state photoacid released fragrance under visible light, stopped releasing when the light was off, and may be reloaded after all the fragrance is released.
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