The Okavango Delta in North Botswana is a hot‐spot of biodiversity within the semi‐arid central part of the South African plateau. This endorheic ecosystem is highly dependent on the annual flood ...that brings freshwater from the highlands of Angola to the North. However, in many places, the groundwater of the Delta is saline and contains very high concentrations of metal and metalloid elements, making it toxic to the flora and fauna. These saline waters have been largely studied and their formation is generally explained through evaporation and evapotranspiration processes. However, no studies have investigated the geochemical composition of the sediments that host the aquifers. Here, we provide a complete sedimentological and geochemical investigation (major, traces and rare earth elements, carbon and oxygen stable isotopes ratios, Sr and Nd isotope ratios) of the various geomorphological and ecological compartments that form the landscape of the SW Okavango Delta. We demonstrate that the non‐connected underground aquifer is capped by a clay layer corresponding to a major event of dust deposition from the Makgadikgadi pan. We suggest that this aquifer may extend outside the island, below the floodplain and that the hydrological structure of the Nxaraga area is indeed composed of two non‐connected aquifers of different origins. Challenging the model based on evaporation and evapotranspiration, we propose that the composition of that allochtonous clay and the in situ reactions between sediment, water and organic matter in a confined aquifer explain the geochemical enrichment of the water.
Key Points
The hydrological structure of the SW Okavango Delta is composed of two non‐connected aquifers
The high alkalinity of groundwater is linked to bio‐geochemical concentration processes in a confined aquifer
Allochtonous, wind‐blown clay deposits play a major role in the hydro‐geochemical structure of the Okavango alluvial fan
We have searched the Wide-field Infrared Survey Explorer first data release for widely separated (≤10 000 au) late T dwarf companions to Hipparcos and Gliese stars. We have discovered a new binary ...system containing a K-band suppressed T8p dwarf WISEP J142320.86+011638.1 and the mildly metal poor (Fe/H =−0.38 ± 0.06) primary BD +01° 2920 (HIP 70319), a G1 dwarf at a distance of 17.2 pc. This new benchmark has T
eff= 680 ± 55 K and a mass of 20-50M
Jup. Its spectral properties are well modelled except for known discrepancies in the Y and K bands. Based on the well-determined metallicity of its companion, the properties of BD +01° 2920B imply that the currently known T dwarfs are dominated by young low-mass objects. We also present an accurate proper motion for the T8.5 dwarf WISEP J075003.84+272544.8.
Background
The best approach for surgical treatment of an infected THA remains controversial. Two-stage revision is believed to result in lower reinfection rates but may result in significant ...functional impairment. Some authors now suggest that single-stage revision may provide comparable results in terms of infection eradication while providing superior functional outcomes.
Questions/purposes
We performed a systematic review to determine whether single- or two-stage revision for an infected THA provides lower reinfection rates and higher functional outcome scores.
Methods
We conducted a comprehensive search of PubMed and Embase, using the search string Infection AND (“total hip replacement” OR “total hip arthroplasty”) AND revision. All studies comparing reinfection rates or functional scores for single- and two-stage revision were retrieved and reviewed. A systematic review was performed according to the PRISMA checklist.
Results
The initial search retrieved 1128 studies. Following strict exclusion criteria, we identified nine comparative studies comparing reinfection rates (all nine studies) or functional scores (four studies) between single- and two-stage revisions. The overall quality of studies was poor with no randomized studies being identified. Groups often varied in their baseline characteristics. There was no consensus among the studies regarding the relative incidence of reinfection between the two procedures. There was a trend toward better functional outcomes in single-stage surgery, but this reached significance in only one study.
Conclusions
In appropriate patients, single-stage revision appears to be associated with similar reinfection rates when compared with two-stage revision with superior functional outcomes. This concurs with earlier studies, but given the methodologic quality of the included studies, these findings should be treated with caution. High-quality randomized studies are needed to compare the two approaches to confirm these findings, and, if appropriate, to determine which patients are appropriate for single-stage revision.
ABSTRACT
We present ALMA CO(1–0) and CO(3–2) observations of the brightest cluster galaxy (BCG) in the 2A 0335+096 galaxy cluster (
z
= 0.0346). The total molecular gas mass of 1.13 ± 0.15 × 10
9
M
...⊙
is divided into two components: a nuclear region and a 7 kpc long dusty filament. The central molecular gas component accounts for 3.2 ± 0.4 × 10
8
M
⊙
of the total supply of cold gas. Instead of forming a rotationally supported ring or disk, it is composed of two distinct, blueshifted clumps south of the nucleus and a series of low-significance redshifted clumps extending toward a nearby companion galaxy. The velocity of the redshifted clouds increases with radius to a value consistent with the companion galaxy, suggesting that an interaction between these galaxies <20 Myr ago disrupted a pre-existing molecular gas reservoir within the BCG. Most of the molecular gas, 7.8 ± 0.9 × 10
8
M
⊙
, is located in the filament. The CO emission is co-spatial with a 10
4
K emission-line nebula and soft X-rays from 0.5 keV gas, indicating that the molecular gas has cooled out of the intracluster medium over a period of 25–100 Myr. The filament trails an X-ray cavity, suggesting that the gas has cooled from low-entropy gas that has been lifted out of the cluster core and become thermally unstable. We are unable to distinguish between inflow and outflow along the filament with the present data. Cloud velocities along the filament are consistent with gravitational free-fall near the plane of the sky, although their increasing blueshifts with radius are consistent with outflow.
Two new MOFs denoted as M-CAU-24 (M = Zr, Ce) based on 1,2,4,5-tetrakis(4-carboxyphenyl)benzene (H
TCPB) were obtained under mild reaction conditions within 15 min. The MOFs with composition M
(μ
-O)
...(μ
-OH)
(OH)
(H
O)
(TCPB)
crystallise in the scu topology, a connectivity hitherto unreported for Zr-MOFs with tetracarboxylate linker molecules. Zr-CAU-24 exhibits UV/blue ligand-based luminescence.
There have been concerns about the long-term survival of unicompartmental knee arthroplasty (UKA). This prospective study reports the 15-year survival and ten-year functional outcome of a consecutive ...series of 1000 minimally invasive Phase 3 Oxford medial UKAs (818 patients, 393 men, 48%, 425 women, 52%, mean age 66 years; 32 to 88). These were implanted by two surgeons involved with the design of the prosthesis to treat anteromedial osteoarthritis and spontaneous osteonecrosis of the knee, which are recommended indications. Patients were prospectively identified and followed up independently for a mean of 10.3 years (5.3 to 16.6). At ten years, the mean Oxford Knee Score was 40 (standard deviation (sd) 9; 2 to 48): 79% of knees (349) had an excellent or good outcome. There were 52 implant-related re-operations at a mean of 5.5 years (0.2 to 14.7). The most common reasons for re-operation were arthritis in the lateral compartment (2.5%, 25 knees), bearing dislocation (0.7%, seven knees) and unexplained pain (0.7%, seven knees). When all implant-related re-operations were considered as failures, the ten-year rate of survival was 94% (95% confidence interval (CI) 92 to 96) and the 15-year survival rate 91% (CI 83 to 98). When failure of the implant was the endpoint the 15-year survival was 99% (CI 96 to 100). This is the only large series of minimally invasive UKAs with 15-year survival data. The results support the continued use of minimally invasive UKA for the recommended indications.
Context.
Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these ...planets are highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST.
Aims.
Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. The star’s low metallicity and the relatively large size and short period of the planet make TOI-2406 b an unusual outcome of planet formation, and its characterisation provides an important observational constraint for formation models.
Methods.
We first infer properties of the host star by analysing the star’s near-infrared spectrum, spectral energy distribution, and
Gaia
parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data.
Results.
We determine the host to be a metal-poor M4 V star, located at a distance of 56 pc, with properties
T
eff
= 3100 ± 75 K,
M
*
= 0.162 ± 0.008
M
⊙
,
R
*
= 0.202 ± 0.011
R
⊙
, and Fe∕H = −0.38 ± 0.07, and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with
R
p
= 2.94 ± 0.17
R
⊕
and
P
= 3.077 d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3
σ
, prompting questions about the dynamical history of the system.
Conclusions.
This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy. Although the planet’s mass remains to be constrained, we estimate the S/N using amass-radius relationship, ranking the system fifth in the population of large sub-Neptunes, with TOI-2406 b having a much lower equilibrium temperature than other spectroscopically accessible members of this population.
Immune escape describes a critical event whereby tumor cells adopt an immunoresistant phenotype to escape adaptive surveillance. We show that expression of a pivotal negative regulator of T-cell ...function, B7-H1, correlates with PI(3) kinase activation in breast and prostate cancer patients. B7-H1-mediated immunoresistance can be attenuated by inhibitors of the PI(3) kinase pathway, and is dependent on S6K1-mediated translational regulation of B7-H1 protein. Breast and prostate carcinoma cells with activated PI(3) kinase lose the immunoresistant phenotype after treatment with B7-H1 siRNA. Conversely, breast and prostate carcinoma cells with minimal PI(3) kinase activation adopt an immunoresistant phenotype when engineered to overexpress B7-H1 protein. These observations describe a mechanism for immune escape from tumor dormancy in humans that relates to oncogenesis.
Background
Anastomotic leak following colorectal surgery is associated with significant morbidity and mortality. With the widespread adoption of laparoscopy, data from initial clinical trials ...evaluating the efficacy of laparoscopic when compared to open surgery may not currently be generalizable. We assess the risk of anastomotic leak after laparoscopic versus open colorectal resection using a nationwide database with standardized definitions.
Methods
The 2012–2013 ACS-NSQIP targeted colectomy data were queried for all elective colorectal resections. Characteristics were compared for those patients undergoing laparoscopic versus open operations. Univariable and multivariable analyses, followed by a propensity score-matched analysis, were performed to assess the impact of laparoscopy on the development of an anastomotic leak.
Results
Of 23,568 patients, 3.4 % developed an anastomotic leak. Laparoscopic surgery was associated with a leak rate of 2.8 % (
n
= 425) and open surgery, 4.5 % (
n
= 378,
p
< 0.0001). Patients who developed a leak were more likely to die within 30 days of surgery (5.7 vs. 0.6 %,
p
< 0.0001). Patients who underwent laparoscopic surgery compared to open were younger (61 vs. 63 years,
p
= 0,
p
= 0.045) and with fewer comorbidities. On univariable analysis laparoscopic surgery was associated with reduced odds of developing an anastomotic leak (OR 0.60,
p
< 0.0001), and this remained after adjusting for all significant preoperative and disease-related confounders (OR 0.69, 95 % CI 0.58–0.82). A propensity score-matched analysis confirmed benefit of laparoscopic surgery over open surgery for anastomotic leak.
Conclusion
Laparoscopic colectomy is safe and associated with reduced odds of developing an anastomotic leak following colectomy when controlling for patient-, disease- and procedure-related factors.
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