Updated Global Warming Potentials and Radiative Efficiencies of Halocarbons and Other Weak Atmospheric Absorbers.

Human activity has led to increased atmospheric concentrations of many gases, including halocarbons, and may lead to emissions of many more gases. Many of these gases are, on a per molecule basis, powerful greenhouse gases, although at present-day concentrations their climate effect is in the so-called weak limit (i.e., their effect scales linearly with concentration). We published a comprehensive review of the radiative efficiencies (RE) and global warming potentials (GWP) for around 200 such compounds in 2013 (Hodnebrog et al., 2013, https://doi.org/10.1002/rog.20013). Here we present updated RE and GWP values for compounds where experimental infrared absorption spectra are available. Updated numbers are based on a revised "Pinnock curve", which gives RE as a function of wave number, and now also accounts for stratospheric temperature adjustment (Shine & Myhre, 2020, https://doi.org/10.1029/2019MS001951). Further updates include the implementation of around 500 absorption spectra additional to those in the 2013 review and new atmospheric lifetimes from the literature (mainly from WMO (2019)). In total, values for 60 of the compounds previously assessed are based on additional absorption spectra, and 42 compounds have REs which differ by >10% from our previous assessment. New RE calculations are presented for more than 400 compounds in addition to the previously assessed compounds, and GWP calculations are presented for a total of around 250 compounds. Present-day radiative forcing due to halocarbons and other weak absorbers is 0.38 [0.33-0.43] W m-2, compared to 0.36 [0.32-0.40] W m-2 in IPCC AR5 (Myhre et al., 2013, https://doi.org/10.1017/CBO9781107415324.018), which is about 18% of the current CO2 forcing.

An experimental and theoretical study of the gas phase kinetics of atomic chlorine reactions with CH3NH2, (CH3)2NH, and (CH3)3N.

The rate coefficients for the reactions of Cl((2)PJ) with methylamine (R1), dimethylamine (R2) and trimethylamine (R3) have been measured using the laser flash photolysis - resonance fluorescence technique as a function of temperature (274-435 K) and pressure (25-400 Torr N2). The experimental data are well-represented by the following temperature- and pressure-independent rate coefficients (10(10) × k/cm(3) molecule(-1) s(-1)): kR1 = 2.90 ± 0.44, kR2 = 3.89 ± 0.58, kR3 = 3.68 ± 0.55; the uncertainties are estimates of accuracy at the 95% confidence level. Potential energy surfaces (PES) for the reactions have been characterized at the MP2/cc-pVTZ level and improved single point energies of stationary points obtained in CCSD(T)-F12a calculations. The PES for all reactions are characterized by the formation of pre and post reaction complexes and submerged barriers. Rate coefficients for the reactions were calculated as a function of temperature and pressure using a master equation model based on the coupled cluster theory results. The calculated rate coefficients are in good agreement with experiment; the overall rate coefficients are relatively insensitive to variations of the barrier heights within typical chemical accuracy, but the predicted branching ratios vary significantly. The inclusion of tunnelling has no effect.

Gas-phase reactions of OH with methyl amines in the presence or absence of molecular oxygen. An experimental and theoretical study.

The rate coefficients for the reaction of OH with the alkyl amines: methylamine (MA), dimethylamine (DMA), trimethylamine (TMA), and ethylamine (EA) have been determined using the technique of pulsed laser photolysis with detection of OH by laser-induced fluorescence as a function of temperature from 298 K to ∼600 K. The rate coefficients (10(11) × k/cm(3) molecule(-1) s(-1)) at 298 K in nitrogen bath gas (typically 5-25 Torr) are: k(OH+MA) = 1.97 ± 0.11, k(OH+DMA) = 6.27 ± 0.63, k(OH+TMA) = 5.78 ± 0.48, k(OH+EA) = 2.50 ± 0.13. The reactions all show a negative temperature dependence which can be characterized as: k(OH+MA) = (1.889 ± 0.053) × 10(-11)(T/298 K)(-(0.56±0.10)), k(OH+DMA) = (6.39 ± 0.35) × 10(-11)(T/298 K)(-(0.75±0.18)), k(OH+TMA) = (5.73 ± 0.15) × 10(-11)(T/298 K)(-(0.71±0.10)), and k(OH+EA) = (2.54 ± 0.08) × 10(-11)(T/298 K)(-(0.68±0.10)). OH and OD reactions have very similar kinetics. Potential energy surfaces (PES) for the reactions have been characterized at the MP2/aug-cc-pVTZ level and improved single point energies of stationary points obtained in CCSD(T) and CCSD(T*)-F12a calculations. The PES for all reactions are characterized by the formation of pre- and post-reaction complexes and submerged barriers. The calculated rate coefficients are in good agreement with experiment; the overall rate coefficients are relatively insensitive to variations of the barrier heights within typical chemical accuracy, but the branching ratios vary significantly. The rate coefficients for the reactions of OH/OD with MA, DMA, and EA do not vary with added oxygen, but for TMA a significant reduction in the rate coefficient is observed consistent with OH recycling from a chemically activated peroxy radical. OH regeneration is pressure-dependent and is not significant at 298 K and atmospheric pressure, but the efficiency of recycling increases strongly with temperature. The PES for OH recycling have been calculated. There is evidence that the primary process in TMA photolysis at 248 nm is the loss of H atoms.

Raman spectroscopy of the system iron(III)-sulfuric acid-water: an approach to Tinto River's (Spain) hydrogeochemistry.

Acid mine drainage is formed when pyrite (FeS(2)) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Tinto River (Huelva, Spain) is an example of this phenomenon. In this study, Raman spectroscopy has been used to investigate the speciation of the system iron(III)-sulfuric acid-water as an approach to Tinto River's aqueous solutions. The molalities of sulfuric acid (0.09 mol/kg) and iron(III) (0.01-1.5 mol/kg) were chosen to mimic the concentration of the species in Tinto River waters. Raman spectra of the solutions reveal a strong iron(III)-sulfate inner-sphere interaction through the nu(1) sulfate band at 981 cm(-1) and its shoulder at 1005 cm(-1). Iron(III)-sulfate interaction may also be facilitated by hydrogen bonds and monitored in the Raman spectra through the symmetric stretching band of bisulfate at 1052 cm(-1) and a shoulder at 1040 cm(-1). Other bands in the low-frequency region of the Raman spectra are attributed to the hydrogen-bonded complexes formation as well.

Inactivation of glucocorticoid receptors in cell-free preparations of rat liver.

We have examined the rates of inactivation of glucocorticoid receptors in cell-free preparations from several rat tissues. The t1/2 of inactivation of the glucocorticoid-binding ability of thymus, heart, and kidney cytosols (37,000 X g supernatants) ranges from 2 to 4 hr at 0 degrees, whereas that of liver is much slower (15 to 25 hr). The rate of inactivation of the glucocorticoid-binding capacity of soluble preparations from liver varies roughly according to the g force at which they have been centrifuged. The 100,000 X g supernatant. The ability of the particulate enzyme to inactivate glucocorticoid receptors at 0 degrees is not affected by protease inhibitors but is inhibited by fluoride and molybdate. The rapid inactivation of unbound glucocorticoid receptors that occurs in a high-speed (100,000 X g) supernatant preparation from rat liver at 25 degrees can be completely inhibited by molybdate. These observations suggest that the inactivation of glucocorticoid receptors observed in cell-free liver preparations in vitro is due to a nonproteolytic enzymatic function.

Atypical EEG abnormalities in children with benign partial (Rolandic) epilepsy.

In order to determine the borderlines of the benign partial epilepsy of children with centrotemporal spike foci ('Rolandic epilepsy') 43 patients with epilepsy and spike foci in the centrotemporal region or elsewhere drawn from the EEG files were re-evaluated as adults. The prognosis was equally good whether the spike focus was in the centrotemporal region or elsewhere, and synchronous paroxystic activity did not make the prognosis worse, but focal temporal low frequency activity did. It is suggested that borderline cases exist between 'Rolandic epilepsy' and other age dependent epilepsies.

Synthesis and biological action of two glucocorticoid alkylating agents.

Two alkylating glucocorticoids have been synthesized in order to test the possibility of alkylating glucocorticoid receptors. The title compounds are 9alpha-fluoro-11beta,16alpha,17alpha,21-tetrahydroxypregna-1,4-diene-3,20-dione 21-[bis(2-chloroethyl)carbamate] 16,17-acetonide (I) and 11beta,17alpha,21-trihydroxypregn-4-ene-3,20-dione 21-[bis(2-chloroethyl)carbamate] (II), prepared from triamcinolone acetonide and cortisol, respectively, through the reaction of the C-21 hydroxyl group with phosgene and di-2-chloroethylamine in the presence of triethylamine. Both compounds are biologically active as inhibitors of the growth of cultured mouse fibroblasts and are able to compete for the specific binding of radiolabeled triamcinolone acetonide to the L929 cell receptor. The bis(2-chloroethyl)carbamate moiety is capable of reacting with nucleophilic groups as evidenced by the colorimetric reaction with 4-(p-nitrobenzyl)pyridine. Both the interaction with the receptor and inhibition of cell growth by these two glucocorticoids are reversible.

Treatment of shunt-related cerebral ventriculitis due to Corynebacterium jeikeium with vancomycin administered intraventricularly. Case report.

A 52-year-old female with subarachnoid haemorrhage and hydrocephalus was treated with external and later internal drainage. She developed ventriculoperitoneal shunt-related ventriculitis caused by Corynebacterium jeikeium. The infection was unsuccessfully treated with intravenous vancomycin. It was controlled only after shunt removal and administration of intraventricular vancomycin as well as systemic vancomycin, rifampicin and fusidic acid. A review of the literature confirmed our experience that vancomycin given intraventricularly is well tolerated and doses can be individualized by measuring vancomycin levels in cerebrospinal fluid.

Adrenalectomy abolishes the stress-induced increase in pituitary cyclic AMP.

We have previously demonstrated that various stressors increase pituitary cyclic AMP in vivo in the rat. In the course of studying the mechanisms mediating this response, we examined the effect of bilateral adrenalectomy on footshock-induced increases in pituitary cyclic AMP. In unoperated rats, intermittent footshock markedly increased pituitary levels of cyclic AMP and plasma levels of corticosterone and prolactin. Adrenalectomy completely abolished the stress-induced increase in pituitary cyclic AMP. The marked increase in plasma prolactin following footshock was not affected by adrenalectomy. Our results indicate that adrenal factors are involved in the stress-induced increase in pituitary cyclic AMP.

Subsensitive pituitary cyclic AMP response to stress following adrenalectomy is not caused by loss of adrenal epinephrine.

We have previously reported that various stressors acutely elevate levels of pituitary cyclic AMP in vivo and that this stress response is not seen in animals tested 7 or 30 days post-adrenalectomy. In this report we present data that demonstrate that the loss of the pituitary cyclic AMP stress response following adrenalectomy is not the result of the loss of stress-induced adrenal epinephrine release. These data show that (1) although administration of epinephrine to intact rats does not elevate levels of pituitary cyclic AMP, administration of epinephrine to adrenalectomized animals does not elevate pituitary cyclic AMP levels in vivo; (2) splanchnic denervation prevents stress-induced adrenal epinephrine release but does not abolish stress-induced increases in pituitary cyclic AMP; and (3) the time course of the developing subsensitive pituitary cyclic AMP response to stress following adrenalectomy is much slower (2 to 3 days) than the loss of circulating epinephrine.

Effect of scenario and experience on interpretation of mach bands.

The creation of the radiographic illusion known as a mach band at the intersection of two images of differing radiopacities can be misinterpreted as pathosis in certain situations. After reviewing instances where misinterpretation may occur, this study asked 33 fourth-year dental students and 40 dentists to interpret the same radiograph involving a maxillary central incisor under two different hypothetical scenarios: first, in the case of a patient requesting vital bleaching, and second, where a patient has received recent trauma to the mouth. Results showed that dental students are more susceptible than dentists to misinterpreting as a horizontal root fracture (a mach band illusion) what is known to be the junction of alveolar crestal bone and root. Furthermore when presented with a scenario of trauma, both students and dentists are more likely to mistake what is being seen as being a fracture line.

Quality of root-end preparations using ultrasonic and rotary instrumentation in cadavers.

Prior investigations have demonstrated dentinal cracking and chipping during ultrasonic preparation of the root-end. This study compared the frequency of cracking and chipping in two groups, cadaver and extracted teeth, using an indirect resin technique. Preparations were performed using either a 33 1/2 inverted cone bur in a high-speed handpiece, or with ultrasonics using a CT-2 tip at either high or low intensity. After replication of the root-end in epoxy resin, all teeth were evaluated for cracking and chipping under scanning electron microscopy. Statistical analysis using a general contingency table or ANOVA with Scheffé post-hoc analysis (p = 0.05) revealed no significant difference between all groups in terms of root-end cracking. In extracted teeth (n = 15), rotary instrumentation produced less chipping than either ultrasonic technique. Varying the intensity was not significant. There was no significant difference between any instrumentation group in cadaver teeth (n = 10) related to the amount of chipping.

Comparison of the obturation of lateral canals by six techniques.

The following obturation techniques were compared on their ability to obturate lateral canals in vitro, lateral condensation (LC), continuous wave of condensation (CW), warm vertical condensation (WV), carrier-based thermoplasticized gutta-percha (CB), warm lateral condensation (WL), and vertically condensed high-temperature gutta-percha (HT). A root canal system with lateral canals in the coronal, middle, and apical thirds was prepared in resin blocks. Each block was obturated using each technique (n = 30, 15 each, with and without sealer). The length of gutta-percha and sealer in each of the lateral canals was measured with a measuring microscope and statistically compared. All techniques obturated all three levels of lateral canals with sealer. WV, CB, and CW were able to fill the lateral canals with gutta-percha significantly better when root canal sealer was used. WV, CB, CW, and HT filled the coronal and middle lateral canals significantly better with gutta-percha than LC or WL condensation. CB and CW filled the apical lateral canal significantly better with gutta-percha than HT, WV, WL, or LC.

Age-related changes in reducible crosslinks of human dental pulp collagen.

Coronal pulp of human third molars from patients ranging in age from 16 to 40 yr was analysed for collagen, protein, calcium and reducible crosslink content. Dihydroxylsinonorleucine (DHLNL) was the major crosslink; it decreased with age. Hydroxylsinonorleucine (HLNL) and lysinonorleucine (LNL) appeared in insignificant amounts. Calcium content increased with age. Based on the premise that collagen synthesis is characterized by the presence of reducible crosslinks, the study showed that coronal pulp collagen synthesis decreases with age; this is accompanied by a decrease in collagen concentration in terms of dry weight and total protein between 16 and 30 hr of age.

Glucocorticoid receptor inactivation and activation by phosphorylation mechanisms.

The specific glucocorticoid binding capacity of cytosol preparations is rapidly lost on incubation at 25 degrees in the absence of ligand. We have examined this process in cell-free preparations from rat thymus, rat liver and mouse fibroblasts (L 929 cells), and we have found that the unoccupied receptor is inactivated by endogenous enzymes to a form that does not bind steroids. The inactivation can be prevented by inhibitors of phosphatase action such as molybdate, fluoride and glucose-1-phosphate. On the basis of this type of evidence we propose that the receptor activity of cytosol can be rendered inactive by a dephosphorylation process. We have now been able to partially reactivate the receptor in both L cell and rat thymus cytosols in an ATP dependent manner. If fibroblast (L cell) cytosol is preincubated to permit receptor inactivation by endogenous enzyme, further inactivation can be prevented by the addition of 10 mM molybdate and reactivation of the binding capacity can be obtained by adding 5 to 10 mM ATP in addition to molybdate. ATP dependent activation is prevented with EDTA and this block is overcome by added magnesium. ADP, CTP, GTP, and UTP are inactive. After inactivating the glucocorticoid binding capacity of rat thymocyte cytosol by incubation for 45 minutes at 25 degrees, considerable reactivation is obtained by addition of dithiothreitol and ATP. This system does not absolutely require the presence of a phosphatase inhibitor in order to show activation. Thymocyte cytosol can also be activated to a steroid binding state by addition of DTT and heat-treated (90 degrees for 15 min.) cytosol from a variety of cell types. The heat-treated cytosol contains ATP, reducing equivalents, and a relatively small molecular weight heat-stable activator(s) that potentiates the reactivation process. Maximum receptor activation is obtained by adding dithiothreitol, heat-stable factor, ATP, and molybdate to the inactivated thymocyte cytosol.

Evaluation of root reinforcement of endodontically treated teeth.

OBJECTIVES: The purpose of this study was to test the root reinforcing capabilities of a glass ionomer sealer and to test whether pretreatment of the instrumented canal to alter or remove the smear layer might enhance the reinforcement. STUDY DESIGN: Ninety single-canaled roots of standardized dimensions were instrumented to International Standards Organization size 45 and were analyzed for resistance to vertical fracture. Six groups were tested (n = 15). RESULTS: No significant difference in fracture resistance was observed between any of the groups. CONCLUSIONS: Under the conditions of this study, reinforcement of endodontically treated mature teeth by placement of adhesive materials in the root was not demonstrated.

Influence of Sub- Versus Top-irrigation and Surfactants in a Recirculating System on Disease Incidence Caused by Phytophthora spp. in Potted Pepper Plants.

Zoospores of Phytophthora capsici spread from inoculated source plants to healthy potted pepper plants located on separate ebb-and-flow benches when the recycled nutrient solution originated from a common reservoir. Amending the recirculating nutrient solution with a surfactant, which selectively kills zoospores, resulted in 100% control of the spread of the pathogen in an ebb-and-flow and a top-irrigated cultural system. Without a surfactant in the recirculating nutrient solution, all plants in an ebb-and-flow cultural system died within 6 weeks. In contrast, all plants in a top-irrigated cultural system died within 2 weeks after inoculation of source plants. These results suggest that the use of recycled irrigation water in an ebb-and-flow cultural system is less conducive to pathogen spread than its use in a top-irrigated cultural system, but may still serve as efficient means of inoculum movement in the absence of control measures.

[Intensive back exercises 5 weeks after surgery of lumbar disk prolapse. A prospective, randomized multicenter trial with a historical control group]. / Intensiv rygtraening fem uger efter lumbal diskusprolapsoperation. En prospektiv, randomiseret multicenterundersøgelse med historisk kontrolgruppe.

An intensive, dynamic rehabilitation program applied to patients who had undergone first time lumbar discectomy was evaluated in a multicentre, clinical trial. Ninety-six patients between 18 and 70 years of age who had been operated within the period September 1989 to May 1990 at the Department of Neurosurgery, Copenhagen County Hospital, Glostrup were consecutively randomized into one of two rehabilitation programs: a) traditional mild, general mobility-improving exercises within pain limits; or b) intensive dynamic back extension and abdominal exercises without low back pain being the limiting factor. Both groups underwent 14 hours of treatment over a period of six weeks, starting five weeks after surgery. Seventy-six patients operated within the period January 1989 to September 1989 formed the historical control group. The results at follow-up at 26 weeks favoured intensive exercises with regard to the patients disability-index and working capabilities. The results are statistically significant. After one year a trend favouring intensive exercises can be observed. No differences in pain or objective measurements were found. A rehabilitation program using intensive exercises without back pain being the limiting factor appears to give the patients increased behavioural support, resulting in improvements in work capacity and reduction in patients' self-rated disability.