East Asian summer monsoon delivers large abundances of very-short-lived organic chlorine substances to the lower stratosphere

Deep convection in the Asian summer monsoon is a significant transport process for lifting pollutants from the planetary boundary layer to the tropopause level. This process enables efficient injection into the stratosphere of reactive species such as chlorinated very-short-lived substances (Cl-VSLSs) that deplete ozone. Past studies of convective transport associated with the Asian summer monsoon have focused mostly on the south Asian summer monsoon. Airborne observations reported in this work identify the East Asian summer monsoon convection as an effective transport pathway that carried record-breaking levels of ozone-depleting Cl-VSLSs (mean organic chlorine from these VSLSs ~500 ppt) to the base of the stratosphere. These unique observations show total organic chlorine from VSLSs in the lower stratosphere over the Asian monsoon tropopause to be more than twice that previously reported over the tropical tropopause. Considering the recently observed increase in Cl-VSLS emissions and the ongoing strengthening of the East Asian summer monsoon under global warming, our results highlight that a reevaluation of the contribution of Cl-VSLS injection via the Asian monsoon to the total stratospheric chlorine budget is warranted.

Rapid ozone depletion after humidification of the stratosphere by the Hunga Tonga Eruption

The eruption of the Hunga Tonga-Hunga Ha'apai volcano on 15 January 2022 offered a good opportunity to explore the early impacts of tropical volcanic eruptions on stratospheric composition. Balloon-borne observations near Réunion Island revealed the unprecedented amount of water vapor injected by the volcano. The enhanced stratospheric humidity, radiative cooling, and expanded aerosol surface area in the volcanic plume created the ideal conditions for swift ozone depletion of 5% in the tropical stratosphere in just 1 week. The decrease in hydrogen chloride by 0.4 parts per million by volume (ppbv) and the increase in chlorine monoxide by 0.4 ppbv provided compelling evidence for chlorine activation within the volcanic plume. This study enhances our understanding of the effect of this unusual volcanic eruption on stratospheric chemistry and provides insights into possible chemistry changes that may occur in a changing climate.

The Hunga Tonga-Hunga Ha'apai Hydration of the Stratosphere

Following the 15 January 2022 Hunga Tonga-Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H₂O, SO₂, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO₂ and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H₂O injection was unprecedented in both magnitude (far exceeding any previous values in the 17-year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H₂O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H₂O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H₂O.

The Hunga Tonga-Hunga Ha'apai Hydration of the Stratosphere

Following the 15 January 2022 Hunga Tonga-Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H₂O, SO₂, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO₂ and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H₂O injection was unprecedented in both magnitude (far exceeding any previous values in the 17-year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H₂O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H₂O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H₂O.

The Hunga Tonga-Hunga Ha'apai Hydration of the Stratosphere

Following the 15 January 2022 Hunga Tonga-Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H₂O, SO₂, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO₂ and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H₂O injection was unprecedented in both magnitude (far exceeding any previous values in the 17-year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H₂O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H₂O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H₂O.

The Hunga Tonga-Hunga Ha'apai Hydration of the Stratosphere

Following the 15 January 2022 Hunga Tonga-Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H₂O, SO₂, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO₂ and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H₂O injection was unprecedented in both magnitude (far exceeding any previous values in the 17-year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H₂O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H₂O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H₂O.

The Hunga Tonga-Hunga Ha'apai Hydration of the Stratosphere

Following the 15 January 2022 Hunga Tonga-Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H₂O, SO₂, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO₂ and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H₂O injection was unprecedented in both magnitude (far exceeding any previous values in the 17-year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H₂O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H₂O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H₂O.

Analysis of outcomes of emergency general and gastrointestinal surgery during the COVID-19 pandemic

BACKGROUND

Few surgical studies have provided adjusted comparative postoperative outcome data among contemporary patients with and without COVID-19 infection and patients treated before the pandemic. The aim of this study was to determine the impact of performing emergency surgery in patients with concomitant COVID-19 infection.

METHODS

Patients who underwent emergency general and gastrointestinal surgery from March to June 2020, and from March to June 2019 in 25 Spanish hospitals were included in a retrospective study (COVID-CIR). The main outcome was 30-day mortality. Secondary outcomes included postoperative complications and failure to rescue (mortality among patients who developed complications). Propensity score-matched comparisons were performed between patients who were positive and those who were negative for COVID-19; and between COVID-19-negative cohorts before and during the pandemic.

RESULTS

Some 5307 patients were included in the study (183 COVID-19-positive and 2132 COVID-19-negative during pandemic; 2992 treated before pandemic). During the pandemic, patients with COVID-19 infection had greater 30-day mortality than those without (12.6 versus 4.6 per cent), but this difference was not statistically significant after propensity score matching (odds ratio (OR) 1.58, 95 per cent c.i. 0.88 to 2.74). Those positive for COVID-19 had more complications (41.5 versus 23.9 per cent; OR 1.61, 1.11 to 2.33) and a higher likelihood of failure to rescue (30.3 versus 19.3 per cent; OR 1.10, 0.57 to 2.12). Patients who were negative for COVID-19 during the pandemic had similar rates of 30-day mortality (4.6 versus 3.2 per cent; OR 1.35, 0.98 to 1.86) and complications (23.9 versus 25.2 per cent; OR 0.89, 0.77 to 1.02), but a greater likelihood of failure to rescue (19.3 versus 12.9 per cent; OR 1.56, 95 per cent 1.10 to 2.19) than prepandemic controls.

CONCLUSION

Patients with COVID-19 infection undergoing emergency general and gastrointestinal surgery had worse postoperative outcomes than contemporary patients without COVID-19. COVID-19-negative patients operated on during the COVID-19 pandemic had a likelihood of greater failure-to-rescue than prepandemic controls.

In VitroActivity of Telithromycin, Quinupristin/Dalfopristin, Linezolid and Comparator Antimicrobial Agents AgainstStaphylococcus aureusClinical Isolates

We have studied the prevalence of the different macrolide, lincosamide, streptograminB (MLS(B)) phenotypes among clinical Staphylococcus aureus isolates erythromycin- and/or oxacillin-resistant; and also the activity of other antimicrobial agents including telithromycin, quinupristin/dalfopristin, linezolid, aminoglycosides, chloramphenicol and vancomycin. We found that 64.86% of S. aureus were oxacillin-resistant. While the most prevalent MLS(B) phenotype among methicillin-resistant S. aureus (MRSA) was constitutive MLS(B) (cMLS) (83%), among methicillin-susceptible S. aureus (MSSA) it was inducible MLS(B) (iMLS(B)) (90%). Kanamycin resistance was more frequent than resistance to other aminoglycosides, being 100% for MRSA. Telithromycin was only active against iMLS(B), MS and erythromycin-susceptible isolates, although resistance rates were found among iMLS(B) MSSA (2.78%). Quinupristin/dalfopristin showed greater activity, with resistance rates of 2.5% for MRSA and 1.53% for MSSA. Both vancomycin and linezolid were fully active against all the isolates tested, with the highest MIC value being 2 microg/ml and 4 microg/ml, respectively. Among MRSA strains, 81.67% displayed resistance to five or more antimicrobials. This multiresistance was more frequently found among cMLS(B) strains (96.38% MRSA resistant to 6-9 agents).

Macrolide resistance phenotypes of commensal viridans group streptococci and Gemella spp. and PCR detection of resistance genes

One hundred and sixty viridans group streptococci (VGS) and 26 Gemella spp. resistant to erythromycin were studied to detect macrolide lincosamide and streptogramin B (MLS(B)) phenotypes and to investigate resistance rates to other antibiotics. The M phenotype was most prevalent in both bacterial groups (59.6% in VGS, 69.2% in gemellae) and the iMLS(B) phenotype was found least often (9.3 and 13.9%, respectively). All isolates with M phenotype had the mef(A/E) gene, being prevalent the mef(E) subclass. cMLS(B) and iMLS(B) strains contained the erm(B) gene, alone or in combination with the mef(A/E) gene. Thirteen isolates were intermediately resistant to quinupristin/dalfopristin and 11 strains showed low susceptibility to telithromycin. Linezolid was active against all the isolates tested and tetracycline resistance was the major one in VGS (41.6%) and Gemella spp. (46.2%).

Epidemiological study of resistance to nalidixic acid and other antibiotics in clinical Yersinia enterocolitica O:3 isolates

Forty-six Yersinia enterocolitica O:3 clinical isolates resistant to nalidixic acid were studied. The use of molecular typing techniques, other indicators of resistance patterns, the plasmid profile, and the presence of genes that encode aminoglycoside-modifying enzyme production suggested to us a clonal dissemination of the studied strains.

Diagnostic imaging in sheep hepatic fascioliasis: ultrasound, computer tomography and magnetic resonance findings

Radiological features and biochemical changes were investigated during the parenchymal and ductal phases of chronic Fasciola hepatica infection in sheep. The activities of plasma aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GGT), plasma levels of IgG anti- F. hepatica and serial ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) findings were studied in eight sheep infected with 150 F. hepatica metacercariae. Experimental fluke infection provoked an increase in plasma level of IgG directed against F. hepatica and in plasma LDH and AST activities from 4 weeks after infection. Enzyme activities did not significantly differ from the baseline after 15 and 12 weeks for LDH and AST, respectively. GGT activity increased from 9 weeks postinfection and still remained significantly elevated at 18 weeks. In the parenchymal phase, both CT and MRI showed nodular lesions in five animals and MRI could also detect early tracks in the subcapsular area in three sheep. Ultrasound findings were nonspecific in this phase. Ductal dilatation was shown by ultrasound, CT and MRI in almost all animals, although MRI was inferior to CT in depicting a mild ductal dilatation. Moving echogenic forms in the dilated bile ducts were observed by ultrasound from 9 weeks postinfection in seven of the eight sheep. Moving worms were only demonstrated in four sheep at CT and in a single sheep at MRI. This study shows that radiological findings may be useful in studies of fluke-induced liver damage.

Transvenous coil embolization of an intrahepatic portosystemic shunt in a dog

To treat an intrahepatic portosystemic shunt in a young dog, thrombogenic material was placed into the vessel lumen (transvenous coil embolization) under fluoroscopic control. One coil was placed into the shunt, followed one month later by two additional coils. Transvenous embolization may become a useful method in the treatment of some portosystemic shunts.

Effects of ischaemia-reperfusion and cyclosporin-A on cardiac muscle ultrastructure

The present study investigates the effects on the cardiac muscle cell of two of the determining factors for the success of organ transplant; ischaemia-perfusion and immunosuppressive treatment with cyclosporin-A (CsA). To this end an abdominal, heterotopic heart transplant model in singenic Sprague-Dawley rats was employed. Three study groups were established: Group I (control, n = 15) animals undergoing heart transplant without treatment; Group II (n = 15) animals undergoing heart transplant and subjected to a daily dose of CsA in a cremophor vehicle (Sandimun) (5 mg/kg/sc); Group III (n = 15): animals undergoing heart transplant and administered a daily dose of pure CsA (5 mg/kg/sc). Recipient animals were sacrificed 7, 14, 21, 30 and 50 days after transplant. During the post-operative period, heart function was assessed by daily abdominal palpation. Graft specimens obtained at each follow-up period were subjected to light and transmission electron microscopy. Immunohistochemical analysis of specimens was performed using the rat macrophage-specific monoclonal antibody MCA-341. The ischaemia/reperfusion process induced considerable alteration to cardiac muscle cells of control animals. Effects, apparent after the first week of transplant, included mitochondrial swelling and loss of cristae, hypertrophy of the sarcoplasmic reticulum and structural changes to sarcomeres. Two weeks after transplant, the myocardium was infiltrated by inflammatory cells. These effects diminished 30 days post-transplant. Cardiac tissues of treated animals (groups II and III) showed similar behaviour although, in the latter group, mitochondrial damage was greater and intense myocardial fibrosis took place. Infiltration of cardiac muscle by white blood cells did not take place until 3 weeks post-implant. These results indicate: a) The ultrastructural changes detected in cardiac fibres of animals of the three study groups were attributable to the ischaemia/reperfusion process rather than to treatment with CsA; b) CsA appears to augment mitochondrial damage and myocardial fibrosis; c) the inflammatory response was delayed and reduced by the immunosupressant; and d) the cremophor administration vehicle did not seem to exert an independent toxic effect on the myocardium.

Catalytic activity of cytochrome oxidase and cytochrome c in apolar solvents containing phospholipids and low amounts of water

Cytochrome c and cytochrome oxidase, in bovine heart submitochondrial particles and in their purified forms, were transferred to a ternary system that contained phospholipids (10 mg/ml toluene), the apolar solvent toluene, and water at concentrations of 13-15 microliters (high water) and 3 microliters (low water) per milliliter of toluene. When the enzymes were transferred back to an all water system, they exhibited full catalytic capacity. In the low water ternary system, cytochrome c could be reduced by ascorbate introduced via inverted micelles. Also in this system, cytochrome oxidase was reduced by ascorbate and cytochrome c but its oxidation was highly impaired. Data on the kinetics of reduction by ascorbate of cytochrome c and cytochrome oxidase under these conditions are presented. Cytochrome oxidase reduced in the organic solvent by ascorbate failed to form a complex with CO, but formed a complex with cyanide introduced via inverted micelles. The oxidized and the ascorbate-reduced cytochrome oxidase-cyanide complex exhibited a trough at 415 nm and a peak at 433 nm. The extent and rate of formation of the cyanide complex were higher with the reduced form of cytochrome oxidase. To achieve protein-protein interactions (cytochrome c-cytochrome oxidase) in the ternary system, it was necessary to extract the two proteins together. There was no functional interaction when they were extracted separately and mixed. In the high water ternary system reduced cytochrome oxidase was not detected, and it oxidized ascorbate at a higher rate than in the low water system; however, this rate was several orders of magnitude lower than in aqueous media.

Denaturation of some general DNA sequences

In this paper we study a DNA model, which is built by considering all probable sequences, where the possibilities of having the base pairs (A-T) or (C-G) in the jth place of the strand helix are considered. This is assumed in order to derive the partition function. From here the denaturation curve is obtained. Finally, some considerations about the correlation coefficients are presented.