Optimal cardiopulmonary resuscitation duration for favorable neurological outcomes after out-of-hospital cardiac arrest

Background A favorable neurological outcome is closely related to patient characteristics and total cardiopulmonary resuscitation (CPR) duration. The total CPR duration consists of pre-hospital and in-hospital durations. To date, consensus is lacking on the optimal total CPR duration. Therefore, this study aimed to determine the upper limit of total CPR duration, the optimal cut-off time at the pre-hospital level, and the time to switch from conventional CPR to alternative CPR such as extracorporeal CPR. Methods We conducted a retrospective observational study using prospective, multi-center registry of out-of-hospital cardiac arrest (OHCA) patients between October 2015 and June 2019. Emergency medical service–assessed adult patients (aged ≥ 18 years) with non-traumatic OHCA were included. The primary endpoint was a favorable neurological outcome at hospital discharge. Results Among 7914 patients with OHCA, 577 had favorable neurological outcomes. The optimal cut-off for pre-hospital CPR duration in patients with OHCA was 12 min regardless of the initial rhythm. The optimal cut-offs for total CPR duration that transitioned from conventional CPR to an alternative CPR method were 25 and 21 min in patients with initial shockable and non-shockable rhythms, respectively. In the two groups, the upper limits of total CPR duration for achieving a probability of favorable neurological outcomes < 1% were 55–62 and 24–34 min, respectively, while those for a cumulative proportion of favorable neurological outcome > 99% were 43–53 and 45–71 min, respectively. Conclusions Herein, we identified the optimal cut-off time for transitioning from pre-hospital to in-hospital settings and from conventional CPR to alternative resuscitation. Although there is an upper limit of CPR duration, favorable neurological outcomes can be expected according to each patient’s resuscitation-related factors, despite prolonged CPR duration.

The Origin and Evolution of Giant Radio Galaxies

Giant radio galaxies are arguably the least understood of jetted active galactic nuclei (AGN). We propose that radio galaxies are the product of large mergers that do not involve radio galaxies or radio quasars, such as in merging spiral galaxies, while giant radio galaxies emerge from a merger involving a parent that in the not-too-distant past harbored a radio galaxy. Predictions following from this are an upper limit to the number fraction of giant radio galaxies to radio galaxies, lower average redshift for giant radio galaxies, a higher incidence of high excitation for giant radio galaxies compared with radio galaxies, and lower average prograde black hole spin values for giant radio galaxies compared to radio galaxies and to bright radio quiet quasars.

Endoscopic Treatment of Upper Tract Urothelial Carcinoma: Challenging the Definition of the Maximal Lesion Size for Safe Ablation

Introduction: With advances in endoscopic treatment of upper tract urothelial carcinoma (UTUC) lesions, the recommended upper limit of lesion size amenable to laser ablation was set to 2 cm. However, this limit is based on expert opinion only, and debate still exists regarding this definition. Objective: To determine the maximal size of the tissue, for which total endoscopic ablation with laser energy is achievable, from a laser performance perspective. Materials and Methods: Simulating endoscopic surgery conditions, renal tissue blocks from pork kidneys in growing size from 1 cm3 to 3 cm3 were totally ablated with Ho:YAG laser (1 J, 10 Hz). The time to ablation was recorded for each tissue mass. Following the ablation, each sample was inspected microscopically by an expert pathologist to determine the extent to which the tissue was destroyed. Results: Time to ablation ranged from 16.4 min for a 1 cm3 mass, to 69.7 min for a 3 cm3 mass. Histologic evaluation after laser ablation showed that ablation was achieved in all tissue masses, and no “unaffected” tissue was present, even for lesions with a size of 3 cm3. Conclusions: This study showed that laser ablation can be achieved for tumor lesions up to a size of 3 cm3. The results of this study can contribute to the debate regarding the limits of endoscopic management of UTUC lesions and strengthen the recommended upper limit of 2 cm3 for endoscopic treatment of tumor lesions.

Optimization of profile and damping layer of plates embedded with acoustic black hole indentations for broadband energy dissipation

Acoustic Black Hole (ABH) plate structure has shown promising potentials of vibration suppression above a cut on frequency. For energy dissipation below the cut on frequency, however, the ABH is less effective due to the absence of wave focusing effect. This work reports a simultaneous optimization of ABH plates for broadband energy dissipation. Two sets of design variables of ABH plates, that is, geometry of the profile and topology of the damping layer, are optimized in an alternatively nested procedure. A novel objective function, namely the upper limit of kinetic energy, is proposed. Modeling of ABH structures is implemented and dynamic characteristic is solved using finite element method. A rectangular plate embedded with two ABH indentations is presented as a numerical example. Influence of frequency ranges in the calculation and mass ratios of the damping layer on results are discussed. The achieved optimal arrangement of the damping layer is found to cover equally, if not more, above the non-ABH (uniform) part of the plate than the ABH area. This is inconsistent with the conventional believe that damping layers should cover as much of the ABH area as possible. Mechanism of the broadband energy dissipation by the optimal solution is demonstrated.

Cancer cell migration on straight, wavy, loop and grid microfibre patterns

Cell migration plays an important role in physiological and pathological processes where the fibrillar morphology of extracellular matrices (ECM) could regulate the migration dynamics. To mimic the morphological characteristics of fibrillar matrix structures, low-voltage continuous electrospinning was adapted to construct straight, wavy, looped and gridded fibre patterns made of polystyrene (of fibre diameter ca. 3 μm). Cells were free to explore their different shapes in response to the directly-adhered fibre, as well as to the neighbouring patterns. For all the patterns studied, analysing cellular migration dynamics of MDA-MB-231 (a highly migratory breast cancer cell line) demonstrated two interesting findings: first, although cells dynamically adjust their shapes and migration trajectories in response to different fibrillar environments, their average step speed is minimally affected by the fibre global pattern; secondly, a switch in behaviour was observed when the pattern features approach the upper limit of the cell body’s minor axis, reflecting that cells’ ability to divert from an existing fibre track is limited by the size along the cell body’s minor axis. It is therefore concluded that the upper limit of cell body’s minor axis might act as a guide for the design of microfibre patterns for different purposes of cell migration.

Abundance Analysis of the J4 Equatorial Knot of the Born-again Planetary Nebula A30

A30 belongs to a class of planetary nebulae identified as “born-again”, containing dense, hydrogen-poor ejecta with extreme abundance discrepancy factors (ADFs), likely associated with a central binary system. We present intermediate-dispersion spectroscopy of one such feature—the J4 equatorial knot. We confirm the apparent physical and chemical segregation of the polar and equatorial knots observed in previous studies, and place an upper limit on the ADF for O2+ of 35, significantly lower than that of the polar knots. These findings further reinforce the theory that the equatorial and polar knots originate from different events.

Rapid Patient-Side Evaluation of Endothelial Glycocalyx Thickness in Healthy Sedated Cats Using GlycoCheck® Software

The endothelial glycocalyx (EG) determines transvascular fluid fluxes, and influences inflammation, coagulation, and capillary blood flow. The GlycoCheck® software calculates EG thickness using sidestream dark field videomicroscopy recordings. This method has not been evaluated for use in cats. The aim of the present study was to evaluate the use of GlycoCheck® for estimating EG thickness in healthy cats, and to investigate the variability of EG thickness in this population. One hundred and one healthy research-purposed cats were included in the study. The cats were sedated, and a handheld videomicroscope, connected to GlycoCheck® software, was used to evaluate the sublingual microvasculature. The parameters measured included perfused boundary region (PBR, an indirect measurement of EG thickness) in vessels between 5 and 25 μm in diameter, valid vessel density, percentage red blood cell filling, and median red blood cell column width. Heart rate, respiratory rate, pulse oximetry and oscillometric blood pressure readings were also recorded. There were 35 neutered male cats, 11 intact males, 38 neutered females, and 17 intact females. The average age was 63 months (range, 11–160 months). Tolerance intervals for PBR (vessel diameter 5–25 μm) were 1.89–3.00 μm (95% CI, lower limit 1.76–2.04, upper limit 2.83–3.13 μm); for valid vessel density were 73.33–333.33 μm/mm2 (95% CI, lower limit 77.00–99.33, upper limit 312.67–350.33 μm/mm2); for percentage red blood cell filling were 59.85–85.07% (95% CI, lower limit 58.97–63.33, upper limit 83.07–88.20 %); and for median red blood cell column width were 5.63–8.59 μm (95% CI, lower limit 5.28–6.07, upper limit 8.14–9.51 μm). There was a negative association between median red blood cell column width and body weight (p = 0.007). The median red blood cell column was significantly wider in intact females when compared to spayed females (p = 0.033). The GlycoCheck® analysis was easily performed in healthy sedated cats. Clinical variables did not have an effect on the EG thickness. These results suggest that this technique could be valuable for evaluation of the EG and microvascular parameters in cats.

Macro-B12 masking B12 deficiency

In clinical practice, the finding of an elevated serum B12 concentration is often the consequence of supplementation with B12 in either oral form or injections. Also, elevated serum B12 may be associated with underlying disorders, like liver diseases or a (haematologic) malignancy. Only a few studies have shown that it may also be the consequence of complex formation of B12-vitamin binding proteins with immunoglobulins, the so-called macro-B12. We describe a young woman who previously was diagnosed with B12 deficiency, and in whom, after cessation of B12 injection treatment, neurologic symptoms re-appeared, and despite this, repeatedly elevated serum B12 concentrations above the upper limit of the assay were found. We demonstrated that this was caused by the presence of macro-B12, which not only resulted in erroneous and longstanding elevated serum B12, but also masked her underlying B12 deficiency.

Locating the special point of hybrid neutron stars

The special point is a feature unique to models of hybrid neutron stars. It represents a location on their mass–radius sequences that is insensitive to the phase transition density. We consider hybrid neutron stars with a core of deconfined quark matter that obeys a constant–sound–speed (CSS) equation of state model and provide a fit formula for the coordinates of the special point as functions of the squared sound speed (cs2) and pressure scale (A) parameters. Using the special point mass as a proxy for the maximum mass of the hybrid stars we derive limits for the CSS model parameters based on the recent NICER constraint on mass and radius of pulsar PSR J0740+6620, 0.36 < Cs min2 < 0.43 and 80 < A[MeV/fm3] < 160. The upper limit for the maximum mass of hybrid stars depends on the upper limit for cs2 so that choosing cs,max2 = 0.6 results in Mmax < 2.7 M⊙, within the mass range of GW190814.