139 research outputs found

    What to do in case of an endoscopic image of gastric necrosis or ischaemia post-funduplication? A case report

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    The association of gastric ischemia with a fundoplication is very rare and its management is not always surgical. The present paper describes the mechanism of post-fundoplication gastric ischemia that occurred in a patient diagnosed with gastroesophageal reflux disease treated with a Nissen-type gastric fundoplication. A clinical case of the Foregut Clinic of the Hospital General de Mexico (HGM) is presented. This is a 24-year-old patient undergoing a Nissen-type fundoplication who was discharged without eventualities and who presented intestinal occlusion, acute gastric dilation and gastric ischemia

    Limberg flap: a review

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    Alexander Alexandrovich Limberg, Surgeon and Dentist, greatly contributed to the modern practice of plastic surgery. He defined the rhomboid flap (Limberg flap). The simplicity and effectiveness of the Limberg flap make it versatile, allowing adequate aesthetics with few complications. The split is made up of two equilateral triangles with angles of 60° and 120°, respectively. An adequate knowledge of the mechanisms of rotation and sliding of skin tissues is essential to indicate the use of this type of flap and to perform it. The skin can be moved from adjacent sites and must be mobile enough to close the defect with minimal tension. The Limberg flap is a flap that takes advantage of the laxity of the skin adjacent to the defect to allow the transposition of tissue with similar characteristics to the excised tissue

    Breast reconstruction: a review

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    Surgeons in the late 19th - 20th century performed radical mastectomies as the only possible treatment for breast cancers. Since then, the medical-surgical/scientific community has been constantly encouraged to develop and study different less invasive alternatives in breast reconstruction. Over time, locoregional perforator flap options have served as practical alternatives to implant-based reconstruction and abdominal flaps, especially in the setting of patients who have received radiation therapy or have a history of failed reconstruction, as they effectively fill the missing volume and respect the musculature of the donor site. Breast reconstruction using strategies with one of the different locoregional flaps can preserve the musculature and innervation of the post-mastectomy site, which manages to reduce possible adverse events. In addition to evaluating the anatomical characteristics of the defect and affected quadrant, it is essential to assess the patient's body constitution and the skills of the surgical team as well as microsurgery training when designing a reconstructive plan. Different research protocols should be developed in the study and development of new medical-surgical therapeutic alternatives; we suggest joint development with tissue engineering

    Large-scale climatic phenomena drive fluctuations in macroinvertebrate assemblages in lowland tropical streams, Costa Rica: The importance of ENSO events in determining long-term (15y) patterns

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    Understanding how environmental variables influence the distribution and density of organisms over relatively long temporal scales is a central question in ecology given increased climatic variability (e.g., precipitation, ENSO events). The primary goal of our study was to evaluate long-term (15y time span) patterns of climate, as well as environmental parameters in two Neotropical streams in lowland Costa Rica, to assess potential effects on aquatic macroinvertebrates. We also examined the relative effects of an 8y whole-stream P-enrichment experiment on macroinvertebrate assemblages against the backdrop of this long-term study. Climate, environmental variables and macroinvertebrate samples were measured monthly for 7y and then quarterly for an additional 8y in each stream. Temporal patterns in climatic and environmental variables showed high variability over time, without clear inter-annual or intra-annual patterns. Macroinvertebrate richness and abundance decreased with increasing discharge and was positively related to the number of days since the last high discharge event. Findings show that fluctuations in stream physicochemistry and macroinvertebrate assemblage structure are ultimately the result of large-scale climatic phenomena, such as ENSO events, while the 8y P-enrichment did not appear to affect macroinvertebrates. Our study demonstrates that Neotropical lowland streams are highly dynamic and not as stable as is commonly presumed, with high intra- and inter-annual variability in environmental parameters that change the structure and composition of freshwater macroinvertebrate assemblages.This study was financed by National Science Foundation (DEB 1122389) to Catherine M. Pringle. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

    Observation of Cabibbo-suppressed two-body hadronic decays and precision mass measurement of the Ωc0\Omega_{c}^{0} baryon

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    The first observation of the singly Cabibbo-suppressed Ωc0ΩK+\Omega_{c}^{0}\to\Omega^{-}K^{+} and Ωc0Ξπ+\Omega_{c}^{0}\to\Xi^{-}\pi^{+} decays is reported, using proton-proton collision data at a centre-of-mass energy of 13TeV13\,{\rm TeV}, corresponding to an integrated luminosity of 5.4fb15.4\,{\rm fb}^{-1}, collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to be B(Ωc0ΩK+)B(Ωc0Ωπ+)=0.0608±0.0051(stat)±0.0040(syst)\frac{\mathcal{B}(\Omega_{c}^{0}\to\Omega^{-}K^{+})}{\mathcal{B}(\Omega_{c}^{0}\to\Omega^{-}\pi^{+})}=0.0608\pm0.0051({\rm stat})\pm 0.0040({\rm syst}), B(Ωc0Ξπ+)B(Ωc0Ωπ+)=0.1581±0.0087(stat)±0.0043(syst)±0.0016(ext)\frac{\mathcal{B}(\Omega_{c}^{0}\to\Xi^{-}\pi^{+})}{\mathcal{B}(\Omega_{c}^{0}\to\Omega^{-}\pi^{+})}=0.1581\pm0.0087({\rm stat})\pm0.0043({\rm syst})\pm0.0016({\rm ext}). In addition, using the Ωc0Ωπ+\Omega_{c}^{0}\to\Omega^{-}\pi^{+} decay channel, the Ωc0\Omega_{c}^{0} baryon mass is measured to be M(Ωc0)=2695.28±0.07(stat)±0.27(syst)±0.30(ext)MeV/c2M(\Omega_{c}^{0})=2695.28\pm0.07({\rm stat})\pm0.27({\rm syst})\pm0.30({\rm ext})\,{\rm MeV}/c^{2}, improving the precision of the previous world average by a factor of four.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-011.html (LHCb public pages

    Measurement of ZZ boson production cross-section in pppp collisions at s=5.02\sqrt{s} = 5.02 TeV

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    The first measurement of the ZZ boson production cross-section at centre-of-mass energy s=5.02\sqrt{s} = 5.02\,TeV in the forward region is reported, using pppp collision data collected by the LHCb experiment in year 2017, corresponding to an integrated luminosity of 100±2pb1100 \pm 2\,\rm{pb^{-1}}. The production cross-section is measured for final-state muons in the pseudorapidity range 2.020GeV/c2.0 20\,\rm{GeV/}\it{c}. The integrated cross-section is determined to be σZμ+μ=39.6±0.7(stat)±0.6(syst)±0.8(lumi) pb \sigma_{Z \rightarrow \mu^{+}\mu^{-}} = 39.6 \pm 0.7\,(\rm{stat}) \pm 0.6\,(\rm{syst}) \pm 0.8\,(\rm{lumi}) \ \rm{pb} for the di-muon invariant mass in the range 60<Mμμ<120GeV/c260<M_{\mu\mu}<120\,\rm{GeV/}\it{c^{2}}. This result and the differential cross-section results are in good agreement with theoretical predictions at next-to-next-to-leading order in the strong coupling. Based on a previous LHCb measurement of the ZZ boson production cross-section in ppPb collisions at sNN=5.02\sqrt{s_{NN}}=5.02 TeV, the nuclear modification factor RpPbR_{p\rm{Pb}} is measured for the first time at this energy. The measured values are 1.20.3+0.5(stat)±0.1(syst)1.2^{+0.5}_{-0.3}\,(\rm{stat}) \pm 0.1\,(\rm{syst}) in the forward region (1.53<yμ<4.031.53<y^*_{\mu}<4.03) and 3.60.9+1.6(stat)±0.2(syst)3.6^{+1.6}_{-0.9}\,(\rm{stat}) \pm 0.2\,(\rm{syst}) in the backward region (4.97<yμ<2.47-4.97<y^*_{\mu}<-2.47), where yμy^*_{\mu} represents the muon rapidity in the centre-of-mass frame.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-010.html (LHCb public pages

    Observation of the decays B(s)0Ds1(2536)K±B_{(s)}^{0}\to D_{s1}(2536)^{\mp}K^{\pm}

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    This paper reports the observation of the decays B(s)0Ds1(2536)K±B_{(s)}^{0}\to D_{s1}(2536)^{\mp}K^{\pm} using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9fb19\,\mathrm{fb}^{-1}. The branching fractions of these decays are measured relative to the normalisation channel B0D0K+KB^{0}\to \overline{D}^{0}K^{+}K^{-}. The Ds1(2536)D_{s1}(2536)^{-} meson is reconstructed in the D(2007)0K\overline{D}^{*}(2007)^{0}K^{-} decay channel and the products of branching fractions are measured to be B(Bs0Ds1(2536)K±)×B(Ds1(2536)D(2007)0K)=(2.49±0.11±0.12±0.25±0.06)×105,\mathcal{B}(B_{s}^{0}\to D_{s1}(2536)^{\mp}K^{\pm})\times\mathcal{B}(D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-})=(2.49\pm0.11\pm0.12\pm0.25\pm0.06)\times 10^{-5}, B(B0Ds1(2536)K±)×B(Ds1(2536)D(2007)0K)=(0.510±0.021±0.036±0.050)×105.\mathcal{B}(B^{0}\to D_{s1}(2536)^{\mp}K^{\pm})\times\mathcal{B}(D_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-}) = (0.510\pm0.021\pm0.036\pm0.050)\times 10^{-5}. The first uncertainty is statistical, the second systematic, and the third arises from the uncertainty of the branching fraction of the B0D0K+KB^{0}\to \overline{D}^{0}K^{+}K^{-} normalisation channel. The last uncertainty in the Bs0B_{s}^{0} result is due to the limited knowledge of the fragmentation fraction ratio, fs/fdf_{s}/f_{d}. The significance for the Bs0B_{s}^{0} and B0B^{0} signals is larger than 10σ10\,\sigma. The ratio of the helicity amplitudes which governs the angular distribution of the Ds1(2536)D(2007)0KD_{s1}(2536)^{-}\to\overline{D}^{*}(2007)^{0}K^{-} decay is determined from the data. The ratio of the SS- and DD-wave amplitudes is found to be 1.11±0.15±0.061.11\pm0.15\pm 0.06 and its phase 0.70±0.09±0.040.70\pm0.09\pm 0.04 rad, where the first uncertainty is statistical and the second systematic.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-014.html (LHCb public pages

    Studies of η\eta and η\eta' production in pppp and ppPb collisions

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    The production of η\eta and η\eta' mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.025.02 and 13 TeV13~{\rm TeV}, and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16 TeV8.16~{\rm TeV}. The studies are performed in center-of-mass rapidity regions 2.5<yc.m.<3.52.5<y_{\rm c.m.}<3.5 (forward rapidity) and 4.0<yc.m.<3.0-4.0<y_{\rm c.m.}<-3.0 (backward rapidity) defined relative to the proton beam direction. The η\eta and η\eta' production cross sections are measured differentially as a function of transverse momentum for 1.5<pT<10 GeV1.5<p_{\rm T}<10~{\rm GeV} and 3<pT<10 GeV3<p_{\rm T}<10~{\rm GeV}, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for η\eta and η\eta' mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of η\eta mesons are also used to calculate η/π0\eta/\pi^0 cross section ratios, which show evidence of a deviation from the world average. These studies offer new constraints on mass-dependent nuclear effects in heavy-ion collisions, as well as η\eta and η\eta' meson fragmentation.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/Publications/p/LHCb-PAPER-2023-030.html (LHCb public pages

    Fraction of χc\chi_c decays in prompt J/ψJ/\psi production measured in pPb collisions at sNN=8.16\sqrt{s_{NN}}=8.16 TeV

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    The fraction of χc1\chi_{c1} and χc2\chi_{c2} decays in the prompt J/ψJ/\psi yield, Fχc=σχcJ/ψ/σJ/ψF_{\chi c}=\sigma_{\chi_c \to J/\psi}/\sigma_{J/\psi}, is measured by the LHCb detector in pPb collisions at sNN=8.16\sqrt{s_{NN}}=8.16 TeV. The study covers the forward (1.5<y<4.01.5<y^*<4.0) and backward (5.0<y<2.5-5.0<y^*<-2.5) rapidity regions, where yy^* is the J/ψJ/\psi rapidity in the nucleon-nucleon center-of-mass system. Forward and backward rapidity samples correspond to integrated luminosities of 13.6 ±\pm 0.3 nb1^{-1} and 20.8 ±\pm 0.5 nb1^{-1}, respectively. The result is presented as a function of the J/ψJ/\psi transverse momentum pT,J/ψp_{T,J/\psi} in the range 1<pT,J/ψ<20<p_{T, J/\psi}<20 GeV/cc. The FχcF_{\chi c} fraction at forward rapidity is compatible with the LHCb measurement performed in pppp collisions at s=7\sqrt{s}=7 TeV, whereas the result at backward rapidity is 2.4 σ\sigma larger than in the forward region for 1<pT,J/ψ<31<p_{T, J/\psi}<3 GeV/cc. The increase of FχcF_{\chi c} at low pT,J/ψp_{T, J/\psi} at backward rapidity is compatible with the suppression of the ψ\psi(2S) contribution to the prompt J/ψJ/\psi yield. The lack of in-medium dissociation of χc\chi_c states observed in this study sets an upper limit of 180 MeV on the free energy available in these pPb collisions to dissociate or inhibit charmonium state formation.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-028.html (LHCb public pages

    Enhanced production of Λb0\Lambda_{b}^{0} baryons in high-multiplicity pppp collisions at s=13\sqrt{s} = 13 TeV

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    The production rate of Λb0\Lambda_{b}^{0} baryons relative to B0B^{0} mesons in pppp collisions at a center-of-mass energy s=13\sqrt{s} = 13 TeV is measured by the LHCb experiment. The ratio of Λb0\Lambda_{b}^{0} to B0B^{0} production cross-sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e+ee^{+}e^{-} collisions, and increases by a factor of 2\sim2 with increasing multiplicity. At relatively low transverse momentum, the ratio of Λb0\Lambda_{b}^{0} to B0B^{0} cross-sections is higher than what is measured in e+ee^{+}e^{-} collisions, but converges with the e+ee^{+}e^{-} ratio as the momentum increases. These results imply that the evolution of heavy bb quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with a statistical hadronization model and implications for the mechanisms enforcing quark confinement are discussed.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-027.html (LHCb public pages
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