scholarly journals Mapping the Photochemistry of European Mid-Latitudes Rivers: An Assessment of Their Ability to Photodegrade Contaminants

Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 424 ◽  
Author(s):  
Luca Carena ◽  
Davide Vione
Keyword(s):  
Steady State ◽  
Photochemical Reactions ◽  
Triplet States ◽  
Long Term Effects ◽  
Water Flow Velocity ◽  
Excited Triplet ◽  
Latitude Belt ◽  
Transient Intermediates ◽  
State Concentration

The abiotic photochemical reactions that take place naturally in sunlit surface waters can degrade many contaminants that pose concern to water bodies for their potentially toxic and long-term effects. This works aims at assessing the ability of European rivers to photoproduce reactive transient intermediates, such as HO• radicals and the excited triplet states of chromophoric dissolved organic matter (3CDOM*), involved in pollutant degradation. A photochemical mapping of the steady-state concentrations of these transients was carried out by means of a suitable modeling tool, in the latitude belt between 40 and 50°N. Such a map allowed for the prediction of the photochemical lifetimes of the phenylurea herbicide isoproturon (mostly undergoing photodegradation upon reaction with HO• and especially 3CDOM*) across different European countries. For some rivers, a more extensive dataset was available spanning the years 1990–2002, which allowed for the computation of the steady-state concentration of the carbonate radicals (CO3•−). With these data, it was possible to assess the time trends of the photochemical half-lives of further contaminants (atrazine, ibuprofen, carbamazepine, and clofibric acid). The calculated lifetimes were in the range of days to weeks, which might or might not allow for efficient depollution depending on the river-water flow velocity.

scholarly journals Immune phase transition under steroid treatment

2021 ◽  
Author(s):  
Sonali Priyadarshini Nayak ◽  
Susmita Roy
Keyword(s):  
Phase Transition ◽  
Steady State ◽  
T Cell ◽  
Stationary Phase ◽  
Latent Period ◽  
Warning Signal ◽  
Immunosuppressive Drugs ◽  
Steroid Treatment ◽  
Long Term Effects

AbstractThe steroid hormone, Glucocorticoid (GC) is a well-known immunosuppressant that controls T cell-mediated adaptive immune response. In this work, we have developed a minimal kinetic network model of T-cell regulation connecting relevant experimental and clinical studies to quantitatively understand the long-term effects of GC on pro-inflammatory T-cell (Tpro) and anti-inflammatory T-cell (Tanti) dynamics. Due to the antagonistic relation between these two types of T-cells, their long-term steady-state population ratio helps us to characterize three classified immune-regulations: (i) weak ([Tpro]>[Tanti]); (ii) strong ([Tpro]<[Tanti]), and (iii) moderate ([Tpro] ∼ [Tanti]); holding the characteristic bistability). In addition to the differences in their long-term steady-state outcome, each immune-regulation shows distinct dynamical phases. In the pre-steady, a characteristic intermediate stationary phase is observed to develop only in the moderate regulation regime. In the medicinal field, the resting time in this stationary phase is distinguished as a clinical latent period. GC dose-dependent steady-state analysis shows an optimal level of GC to drive a phase-transition from the weak/auto-immune prone to the moderate regulation regime. Subsequently, the pre-steady state clinical latent period tends to diverge near that optimal GC level where [Tpro]: [Tanti] is highly balanced. The GC-optimized elongated stationary phase explains the rationale behind the requirement of long-term immune diagnostics, especially when long-term GC-based chemotherapeutics and other immunosuppressive drugs are administrated. Moreover, our study reveals GC sensitivity of clinical latent period which might serve as an early warning signal in the diagnosis of different immune phases and determining immune phase-wise steroid treatment.

Long-Term Effects of Prior Heat Shock on Neuronal Potassium Currents Recorded in a Novel Insect Ganglion Slice Preparation

1999 ◽  
Vol 81 (2) ◽  
pp. 795-802 ◽  
Author(s):  
J. M. Ramirez ◽  
F. P. Elsen ◽  
R. M. Robertson
Keyword(s):  
Steady State ◽  
Heat Shock ◽  
Outward Current ◽  
Potassium Currents ◽  
Respiratory Neurons ◽  
Long Term Effects ◽  
Slice Preparation ◽  
Population Activity ◽  
Steady State Current

Long-term effects of prior heat shock on neuronal potassium currents recorded in a novel insect ganglion slice preparation. Brief exposure to high temperatures (heat shock) induces long-lasting adaptive changes in the molecular biology of protein interactions and behavior of poikilotherms. However, little is known about heat shock effects on neuronal properties. To investigate how heat shock affects neuronal properties we developed an insect ganglion slice from locusts. The functional integrity of neuronal circuits in slices was demonstrated by recordings from rhythmically active respiratory neurons and by the ability to induce rhythmic population activity with octopamine. Under these “functional” in vitro conditions we recorded outward potassium currents from neurons of the ventral midline of the A1 metathoracic neuromere. In control neurons, voltage steps to 40 mV from a holding potential of −60 mV evoked in control neurons potassium currents with a peak current of 10.0 ± 2.5 nA and a large steady state current of 8.5 ± 2.6 nA, which was still activated from a holding potential of −40 mV. After heat shock most of the outward current inactivated rapidly (peak amplitude: 8.4 ± 2.4 nA; steady state: 3.6 ± 2.0 nA). This current was inactivated at a holding potential of −40 mV. The response to temperature changes was also significantly different. After changing the temperature from 38 to 42°C the amplitude of the peak and steady-state current was significantly lower in neurons obtained from heat-shocked animals than those obtained from controls. Our study indicates that not only heat shock can alter neuronal properties, but also that it is possible to investigate ion currents in insect ganglion slices.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

Long-Term Effects of Head Lice Tx Unknown

2012 ◽  
Vol 43 (3) ◽  
pp. 42
Author(s):  
MITCHEL L. ZOLER
Keyword(s):  
Head Lice ◽  
Long Term Effects
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