Phyllosilicate fabric characterization by Low‐Temperature Anisotropy of Magnetic Susceptibility (LT‐AMS)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94895/1/grl16043.pd

An interventional nationwide surveillance program lowers postoperative infection rates in elective colorectal surgery: a cohort study (2008–2019)

Colorectal surgery; Postoperative infection; Cohort studiesCirugía colorrectal; Infección postoperatoria; Estudios de cohortesCirurgia colorectal; Infecció postoperatòria; Estudis de cohortsBackground: Colorectal surgery is associated with the highest rate of surgical site infection (SSI). This study analyses the effectiveness of an interventional surveillance program on SSI rates after elective colorectal surgery. Material and methods: Cohort study showing temporal trends of SSI rates and Standardized Infection Ratio (SIR) in elective colorectal surgery over a 12-year period. Prospectively collected data of a national SSI surveillance program was analysed and the effect of specific interventions was evaluated. Patient and procedure characteristics, as well as SIR and SSI rates were stratified by risk categories and type of SSI analysed using stepwise multivariate logistic regression models. Results: In a cohort of 42,330 operations, overall cumulative SSI incidence was 16.31%, and organ-space SSI (O/S-SSI) was 8.59%. There was a 61.63% relative decrease in SSI rates (rho = -0.95804). The intervention which achieved the greatest SSI reduction was a bundle of 6 measures. SSI in pre-bundle period was 19.73% vs. 11.10% in post-bundle period (OR 1.969; IC 95% 1.860-2.085; p < 0.0001). O/S-SSI were 9.08% vs. 6.06%, respectively (OR 1.547; IC 95% 1.433-1.670; p < 0.0001). Median length of stay was 7 days, with a significant decrease over the studied period (rho = -0.98414). Mortality of the series was 1.08%, ranging from 0.35% to 2.0%, but a highly significant decrease was observed (rho = -0.67133). Conclusions: Detailed analysis of risk factors and postoperative infection in colorectal surgery allows strategies for reducing SSI incidence to be designed. An interventional surveillance program has been effective in decreasing SIR and SSI rates

Oxidant-Free Au(I)-Catalyzed Halide Exchange and Csp2–O Bond Forming Reactions

Au has been demonstrated to mediate a number of organic transformations through the utilization of its π Lewis acid character, Au(I)/Au(III) redox properties or a combination of both. As a result of the high oxidation potential of the Au(I)/Au(III) couple, redox catalysis involving Au typically requires the use of a strong external oxidant. This study demonstrates unusual external oxidant-free Au(I)-catalyzed halide exchange (including fluorination) and Csp2–O bond formation reactions utilizing a model aryl halide macrocyclic substrate. Additionally, the halide exchange and Csp2–O coupling reactivity could also be extrapolated to substrates bearing a single chelating group, providing further insight into the reaction mechanism. This work provides the first examples of external oxidant-free Au(I)-catalyzed carbon–heteroatom cross-coupling reactions

Rock Magnetism of Lapilli and Lava Flows from Cumbre Vieja Volcano, 2021 Eruption (La Palma, Canary Islands): Initial Reports

We present initial rock magnetic results for both lava flows and lapilli produced by the 2021 eruption of the Cumbre Vieja, La Palma (Canary Islands). Samples were taken during the eruption to minimize early alteration and weathering of the rocks and tephra. Standard procedures included progressive alternating field and thermal demagnetization, hysteresis curves, thermomagnetic experiments, progressive acquisition of isothermal remanent magnetization (IRM), and First-Order Reversal Curves (FORCs). Overall, our observations, including low to medium unblocking temperatures, isothermal remanent magnetization to 1 Tesla, and the abundance of wasp-waist hysteresis loops, strongly suggest the presence of Ti-rich titanomagnetites as the main remanence carriers in both lava flows and lapilli, in addition to some hematite as well. Whereas the former has been directly seen (SEM), hematite is elusive with nonmagnetic-based methods. Rock magnetic data, on a Day plot, also reveal that the magnetic grain size tends to be larger in the lava flows than in the lapilli.This research was funded by Agencia Estatal de Investigación, Spain, grant no. PID2019-105796GB-00/AEI/10.13039/501100011033

Observació directa de cicles redox de Ag(I)/Ag(III) de dos electrons en catàlisi de funcionalització d'halurs d'aril

La plata és avui dia àmpliament utilitzada en catàlisi homogènia per a la síntesi de compostos orgànics a causa del seu caràcter d'àcid de Lewis i el seu poder oxidant. La Ag(I) és un potent oxidant monoelectrònic que troba utilitat en un gran nombre de processos catalítics. Tanmateix, els cicles catalítics de dos electrons, molt comuns en la química organometàl·lica dels metalls nobles, no han estat mai considerats possibles per a la plata. En aquest estudi descrivim un cicle catalític Ag(I)/Ag(III) que és operatiu en una reacció model d'acoblament creuat per a la formació d'enllaços C–O. Espècies aril–Ag(III) han estat inequívocament identificades com a intermedis d'aquest cicle catalític. L'estudi de la síntesi i la reactivitat de l'esmentat complex ha permès per primera vegada la caracterització de les etapes d'addició oxidant i eliminació reductiva de formació d'enllaços carboni–nucleò- fil en centres monometàl·lics de plata. El present treball demostra que els processos d'eliminació reductiva en espècies aril–Ag(III) són efectius en reaccions d'acoblament creuat per a la formació d'enllaços C–O, C–N, C–S, C–C i C–halur, incloses les reaccions de fluoració d'arils. Aquest estudi suposa un punt de partida per a l'expansió de la química redox Ag(I)/Ag(III) a noves metodologies per a la síntesi orgànica, en analogia a la química d'acoblament creuat del coure o el pal·ladi. A més, els resultats descrits proporcionen una comprensió mecanística fonamental única en les reaccions d'acoblament creuat catalitzades per plata i refuten la concepció generalment acceptada que la química redox de la plata només pot provenir de processos d'un sol electró.Silver is extensively used in homogeneous catalysis for organic synthesis owing to its Lewis acidity and unique high oxidation power. The high oxidation potential of Ag(I) makes it a powerful one-electron oxidant that finds utility in a large number catalytic processes. However, two-electron redox catalytic cycles, most common in noble metal organometallic reactivity, have never been considered. Herein we show that an Ag(I)/Ag(III) catalytic cycle is operative in a model C–O cross-coupling reaction. Aryl–Ag(III) species have been unequivocally identified as an intermediate in the catalytic cycle. The study of the synthesis and reactivity of this complex has enabled for the first time the direct characterization of aryl halide oxidative addition and carbon–nucleophile bond-forming reductive elimination steps at monometallic silver centers. This report demonstrates that reductive elimination processes at aryl–Ag(III) species are effective for C–O, C–N, C–S, C–C and C–halide coupling reactions, including aryl fluorination. We anticipate our study as the starting point for expanding Ag(I)/Ag(III) redox chemistry into new methodologies for organic synthesis, resembling well-known copper or palladium cross-coupling catalysis. Furthermore, findings described herein provide a unique fundamental mechanistic understanding of Ag-catalyzed cross-coupling reactions and dismiss the generally accepted conception that silver redox chemistry can only arise from one-electron processes

Oral antibiotic prophylaxis lowers surgical site infection in elective colorectal surgery: results of a pragmatic cohort study in Catalonia

Background: The role of oral antibiotic prophylaxis (OAP) and mechanical bowel preparation (MBP) in the prevention of surgical site infection (SSI) after colorectal surgery is still controversial. The aim of this study was to analyze the effect of a bundle including both measures in a National Infection Surveillance Network in Catalonia. Methods: Pragmatic cohort study to assess the effect of OAP and MBP in reducing SSI rate in 65 hospitals, comparing baseline phase (BP: 2007-2015) with implementation phase (IP: 2016-2019). To compare the results, a logistic regression model was established. Results: Out of 34,421 colorectal operations, 5180 had SSIs (15.05%). Overall SSI rate decreased from 18.81% to 11.10% in BP and IP, respectively (OR 0.539, CI95 0.507-0.573, p < 0.0001). Information about bundle implementation was complete in 61.7% of cases. In a univariate analysis, OAP and MBP were independent factors in decreasing overall SSI, with OR 0.555, CI95 0.483-0.638, and OR 0.686, CI95 0.589-0.798, respectively; and similarly, organ/space SSI (O/S-SSI) (OR 0.592, CI95 0.494-0.710, and OR 0.771, CI95 0.630-0.944, respectively). However, only OAP retained its protective effect at both levels at multivariate analyses. Conclusions: oral antibiotic prophylaxis decreased the rates of SSI and O/S-SSI in a large series of elective colorectal surger

Options in the surgical treatment of cavemous haemangioma of the rectum

El hemangioma cavernoso difuso del recto es una malformación congénita poco frecuente. de tipo hamartomatoso. Suele manifestarse en forma de rectorragias abundantes. en pacientes jóvenes y habitualmente requiere cirugía. Para evitar la resección abdóminoperineal en estos pacientes, se ha descrito una técnica de tipo «pull-through», que incluye una mucosectomía amplia del recto y una anastomosis colo-anal. Sin embargo. nosotros consideramos que si es posible descartar preoperatoriamente la afectación de otras vísceras pélvicas, es más adecuado realizar de una proctectomía conservadora seguida de anastomosis coloanal. Presentamos un caso en un paciente de 17 años

H2 oxidation versus organic substrate oxidation in non-heme iron mediated reactions with H2O2

Herein we show that species generated upon reaction of α-[Fe(CF3SO3)2(BPMCN)] (BPMCN = N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane) with H2O2 (putatively [FeV(O)(OH)(BPMCN)]) is able to efficiently oxidize H2 to H2O even in the presence of organic substrates, while species formed in the presence of acetic acid (putatively [FeV(O)(OAc)(BPMCN)]) prefer organic substrate oxidation over H2 activation. Mechanistic implications have been analysed with the aid of computational methodsThis work was supported by Spanish Ministerio de Economia y Competitividad (CTQ2012-37420-C02-02 and 01) European Research Council (StG 239910), and Generalitat de Catalunya (2014 SGR 862 and ICREA Academia award to MC). J.Ll.-F. thanks the CELLEX foundation for the starting career program for financial suppor