Observation of the effect of gravity on the motion of antimatter.

Einstein's general theory of relativity from 1915 remains the most successful description of gravitation. From the 1919 solar eclipse to the observation of gravitational waves, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe.

Lung Injury Is Induced by Abrupt Increase in Respiratory Rate but Prevented by Recruitment Maneuver in Mild Acute Respiratory Distress Syndrome in Rats.

Background: Gradually changing respiratory rate (RR) during time to reduce ventilation-induced lung injury has not been investigated. The authors hypothesized that gradual, compared with abrupt, increments in RR would mitigate ventilation-induced lung injury and that recruitment maneuver before abruptly increasing RR may prevent injurious biologic impact.

Methods: Twenty-four hours after intratracheal administration of Escherichia coli lipopolysaccharide, 49 male Wistar rats were anesthetized and mechanically ventilated (tidal volume, 6 ml/kg; positive end-expiratory pressure, 3 cm H2O) with RR increase patterns as follows (n = 7 per group): (1) control 1, RR = 70 breaths/min for 2 h; (2) and (3) abrupt increases of RR for 1 and 2 h, respectively, both for 2 h; (4) shorter RR adaptation, gradually increasing RR (from 70 to 130 breaths/min during 30 min); (5) longer RR adaptation, more gradual increase in RR (from 70 to 130 breaths/min during 60 min), both for 2 h; (6) control 2, abrupt increase of RR maintained for 1 h; and (7) control 3, recruitment maneuver (continuous positive airway pressure, 30 cm H2O for 30 s) followed by control-2 protocol.

Brazilian Society of Surgical Oncology consensus on fertility-sparing surgery for cervical cancer.

Objective: Several controversies remain on conservative management of cervical cancer. Our aim was to develop a consensus recommendation on important and novel topics of fertility-sparing treatment of cervical cancer.

Methods: The consensus was sponsored by the Brazilian Society of Surgical Oncology (BSSO) from March 2020 to September 2020 and included a multidisciplinary team of 55 specialists.

Rationale and limitations of the SpO2/FiO2 as a possible substitute for PaO2/FiO2 in different preclinical and clinical scenarios.

Although the PaO 2/FiO 2 derived from arterial blood gas analysis remains the gold standard for the diagnosis of acute respiratory failure, the SpO2/FiO2 has been investigated as a potential substitute. The current narrative review presents the state of the preclinical and clinical literature on the SpO2/FiO2 as a possible substitute for PaO2/FiO2 and for use as a diagnostic and prognostic marker; provides an overview of pulse oximetry and its limitations, and assesses the utility of SpO2/ FiO2 as a surrogate for PaO2/FiO2 in COVID-19 patients. Overall, 49 studies comparing SpO2/FiO2 and PaO2/FiO2 were found according to a minimal search strategy.

Sympathetic cooling of positrons to cryogenic temperatures for antihydrogen production.

The positron, the antiparticle of the electron, predicted by Dirac in 1931 and discovered by Anderson in 1933, plays a key role in many scientific and everyday endeavours. Notably, the positron is a constituent of antihydrogen, the only long-lived neutral antimatter bound state that can currently be synthesized at low energy, presenting a prominent system for testing fundamental symmetries with high precision. Here, we report on the use of laser cooled Be ions to sympathetically cool a large and dense plasma of positrons to directly measured temperatures below 7 K in a Penning trap for antihydrogen synthesis.