Low temperature
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- MeSH
- hygiena práce MeSH
- infekční nemoci přenos MeSH
- konzervace krve MeSH
- laboratorní infekce etiologie MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
Chlorosomes from green photosynthetic bacteria belong to the most effective light-harvesting antennas found in nature. Quinones incorporated in bacterichlorophyll (BChl) c aggregates inside chlorosomes play an important redox-dependent photo-protection role against oxidative damage of bacterial reaction centers. Artificial BChl c aggregates with and without quinones were prepared. We applied hole-burning spectroscopy and steady-state absorption and emission techniques at 1.9 K and two different redox potentials to investigate the role of quinones and redox potential on BChl c aggregates at low temperatures. We show that quinones quench the excitation energy in a similar manner as at room temperature, yet the quenching process is not as efficient as for chlorosomes. Interestingly, our data suggest that excitation quenching partially proceeds from higher excitonic states competing with ultrafast exciton relaxation. Moreover, we obtained structure-related parameters such as reorganization energies and inhomogeneous broadening of the lowest excited state, providing experimental ground for theoretical studies aiming at designing plausible large-scale model for BChl c aggregates including disorder.
sv.
- MeSH
- biologie MeSH
- kryochirurgie MeSH
- lyofilizace MeSH
- nízká teplota MeSH
- terapeutická hypotermie MeSH
- Publikační typ
- periodika MeSH
- Konspekt
- Biologické vědy
- NLK Obory
- biologie
- fyzika, biofyzika
The cryopreservation techniques proposed for embryos of the fruit fly Drosophila melanogaster are not yet ready for practical use. Alternative methods for long-term storage of D. melanogaster strains, although urgently needed, do not exist. Herein, we describe a narrow interval of low temperatures under which the larvae of D. melanogaster can be stored in quiescence for up to two months. The development of larvae was arrested at the pre-wandering stage under fluctuating thermal regime (FTR), which simultaneously resulted in diminishing the accumulation of indirect chill injuries. Our physiological, metabolomic, and transcriptomic analyses revealed that compared to larvae stored at constant low temperatures, the larvae stored under FTR conditions were able to decrease the rates of depletion of energy substrates, exploited brief warm episodes of FTR for homeostatic control of metabolite levels, and more efficiently exerted protection against oxidative damage.
This paper presents the results of lab-scale experiments on low temperature thermal pre-treatment (less than 100 °C) prior to anaerobic digestion of sewage sludge. Two heating ways, microwave heating (MH) and conventional heating (CH), and two types of sludge, primary and waste activated sludge, were compared under the same experimental conditions. The degree of solubilisation produced by MH and CH up to 72, 82 and 93 °C was firstly estimated. For both types of heating, increase in soluble chemical oxygen demand (COD) caused by the pre-treatment was about 14% on waste activated sludge and only 3% on primary sludge. The final temperature of 72 °C resulted as the most cost-effective in terms of additional soluble COD per unit of energy required. Subsequently, five series of biochemical methane potential mesophilic assays were run in 120 mL serum bottles on sludge samples pre-treated at 72 °C. When compared with control reaction vessels, no significant differences were noticed in net methane production of pre-treated primary sludge, whereas a relevant increase occurred regarding the pre-treated waste activated sludge. It was also observed that the trend of methane content in biogas during the batch tests can be described by a second order polynomial.
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