Subducting volcaniclastic-rich upper crust supplies fluids for shallow megathrust and slow slip.

Recurring slow slip along near-trench megathrust faults occurs at many subduction zones, but for unknown reasons, this process is not universal. Fluid overpressures are implicated in encouraging slow slip; however, links between slow slip, fluid content, and hydrogeology remain poorly known in natural systems. Three-dimensional seismic imaging and ocean drilling at the Hikurangi margin reveal a widespread and previously unknown fluid reservoir within the extensively hydrated (up to 47 vol % H2O) volcanic upper crust of the subducting Hikurangi Plateau large igneous province. This ~1.5 km thick volcaniclastic upper crust readily dewaters with subduction but retains half of its fluid content upon reaching regions with well-characterized slow slip. We suggest that volcaniclastic-rich upper crust at volcanic plateaus and seamounts is a major source of water that contributes to the fluid budget in subduction zones and may drive fluid overpressures along the megathrust that give rise to frequent shallow slow slip.

Preferential Retention and Transport of Perfluorooctanesulfonic Acid in a Dolomite Aquifer.

Per- and polyfluoroalkyl substances (PFAS) can represent a significant human health risk if present in aquifers used as a drinking water source. Accurate assessment of PFAS exposure risks requires an improved understanding of field-scale PFAS transport in groundwater. Activities at a former firefighter training site in University Park, Pennsylvania introduced perfluorooctanesulfonic acid (PFOS) to the underlying dolomite aquifer. Groundwater sampling from 2015 to 2018 delineated a PFOS plume with two concentration maxima located approximately 20 and approximately 220 m downgradient of the training site, separated by a zone of lower concentrations. We use a combination of analytical and numerical models, informed by independent measurements of aquifer porosity, hydraulic conductivity, and organic carbon content, to interpret the field observations. Our analysis demonstrates that preferential retention and transport resulting from simple heterogeneity in bedrock sorption, as caused by organic carbon (OC) content variability, provides a plausible explanation for plume separation. Dissolved PFOS partitions strongly to organic solids (high Koc ), so even a small OC (<1 wt%) significantly retards PFOS transport, whereas zones with little to no OC allow for transport rates that approximate those of a conservative solute. Our work highlights an important consideration for modeling the groundwater transport of PFOS, and other compounds with high Koc . In aquifers with discrete layers of varying OC, models using a uniform site-average OC will underestimate transport distances, thereby misrepresenting exposure risks for downgradient communities.

[Monteggia lesions and equivalent lesions in children]. / Monteggia-Läsionen und Monteggia-Äquivalent-Läsionen im Kindesalter.

BACKGROUND: Missed Monteggia lesions results in chronic luxation and deficits in the range of motion. The overall therapeutic goal is a quick and stable anatomical repositioning of the lesion. The prognosis of Monteggia lesions in comparison to its equivalents is better, especially with early diagnosis. OBJECTIVE: Comparison of the types of lesion, treatment modalities, hospitalization, immobilization, movement deficits, perioperative complications and outcome. MATERIAL AND METHODS: Retrospective study of 62 patients treated with acute Monteggia lesions and its equivalents during the period of 2009-2020. RESULTS: 2 patients were treated with cast immobilization only, 11 with repositioning under general anesthesia, 39 with intramedullary nailing and 10 with screw osteosynthesis. The average observation period was 4.1 months. Patients with cast immobilization needed only a short hospitalization (2 days), patients with repositioning or osteosynthesis had longer hospitalization (3.4 or 4.3 days, respectively). Deficits of the range of motion did not appear in simple cast immobilization or intramedullary nailing without reduction; however, patients with closed reduction or screw osteosynthesis showed some degree of deficits (9% and 40%, respectively). Monteggia lesions needed shorter hospitalization than their equivalents (3.7 vs. 4.5 days) and had less deficits in the range of motion (7% vs. 21%). CONCLUSION: Most patients were treated with osteosynthesis (79%). Patients with Monteggia lesions had a better outcome than patients with equivalent lesions.

Validation of the Hungarian Version of the SarQoL® Questionnaire and Its Association with the SARC-F Screening Tool.

BACKGROUND: Following the publication of a culturally adapted version of the original SarQoL® questionnaire in Hungarian language, we aimed to test its psychometric properties and its association with the SARC-F screening instrument. DESIGN: This cross-sectional validation study recruited elderly people from 2 nursing homes and an endocrinology clinic. All participants were screened for sarcopenia with the SARC-F tool, had their muscle mass measured with bioelectrical impedance analysis, as well as grip strength and gait speed. Sarcopenia was diagnosed with the EWGSOP2 criteria. Participants completed the SarQoL questionnaire, the SF-36, the EQ-5D and the EQ-VAS. Validation consisted of analyzing discriminative power, internal consistency, construct validity and floor- and ceiling effects. A multivariate regression model was used to evaluate the association between QoL, the SARC-F questionnaire, and a number of demographic and clinical variables. RESULTS: A total of 70 participants, aged 80.00 (68.50 - 82.50) years, were included. Discriminative power between sarcopenic and nonsarcopenic subjects was found for all domains, except domain 7 (Fears) when dividing study population based on the SARC-F score. We also found significantly lower QoL for domains 4 (Functionality) and 5 (Activities of daily living) when splitting participants based on muscle strength (Probable sarcopenia - EWGSOP2 definition). All domains showed a strong or moderate correlation with the total SarQoL score. Conceptually similar domains of other generic QoL questionnaires significantly correlated with the total SarQol score, confirming its convergent validity. Low correlations were found with different domains (divergent validity). No floor or ceiling effects were observed. Using a regression model, the components "strength" and "stair climbing" of the SARC-F questionnaire were significantly associated with the QoL of our patients assessed with the SarQoL instrument. CONCLUSION: Sarcopenia risk assessed with the Sarc-F instrument was significantly associated with QoL measured with the SarQol questionnaire. High internal consistency, convergent and divergent validity and no floor and ceiling effects characterised the Hungarian language SarQoL® questionnaire. Due to some limitations, further multi-center designed studies are needed to verify the validity of the SarQol questionnaire.

ROMANIAN TRANSLATION AND VALIDATION OF THE SARC-F QUESTIONNAIRE.

CONTEXT: Several studies have addressed the impact of sarcopenia on various health outcomes. As the most critical issue is the early identification of individuals, a short screening tool may help clinicians to simply test for sarcopenia and start early management of the disease. Recently, a simple questionnaire, Sarc-F was provided that may adequately realize this aim. SUBJECTS AND METHODS: To validate the questionnaire we translated the original Sarc-F according to the recommended methodology. A total of 80 people, aged 65+ were evaluated for sarcopenia. Muscle mass, strength, and physical performance were measured. Volunteers completed the Sarc-F as well as other two questionnaires. Discriminative power, reliability, construct validity analyses, specificity, sensitivity, negative and positive predictive value evaluations were made. RESULTS: A good discriminative power and internal consistency were found. With the functional sarcopenia diagnostic criteria the test demonstrates a high specificity (84%). The positive and negative predictive values were: 78% and 77%. Using the more conservative diagnostic criteria the negative predictive value was: 85.4%, sufficient to rule out those not at risk of having sarcopenia and eliminate the need for further investigations. CONCLUSIONS: A valid Romanian Sarc-F questionnaire is now available to simply detect patients at risk/no risk of sarcopenia.

Slow slip source characterized by lithological and geometric heterogeneity.

Slow slip events (SSEs) accommodate a significant proportion of tectonic plate motion at subduction zones, yet little is known about the faults that actually host them. The shallow depth (<2 km) of well-documented SSEs at the Hikurangi subduction zone offshore New Zealand offers a unique opportunity to link geophysical imaging of the subduction zone with direct access to incoming material that represents the megathrust fault rocks hosting slow slip. Two recent International Ocean Discovery Program Expeditions sampled this incoming material before it is entrained immediately down-dip along the shallow plate interface. Drilling results, tied to regional seismic reflection images, reveal heterogeneous lithologies with highly variable physical properties entering the SSE source region. These observations suggest that SSEs and associated slow earthquake phenomena are promoted by lithological, mechanical, and frictional heterogeneity within the fault zone, enhanced by geometric complexity associated with subduction of rough crust.

Recurring and triggered slow-slip events near the trench at the Nankai Trough subduction megathrust.

The discovery of slow earthquakes has revolutionized the field of earthquake seismology. Defining the locations of these events and the conditions that favor their occurrence provides important insights into the slip behavior of tectonic faults. We report on a family of recurring slow-slip events (SSEs) on the plate interface immediately seaward of repeated historical moment magnitude (Mw) 8 earthquake rupture areas offshore of Japan. The SSEs continue for days to several weeks, include both spontaneous and triggered slip, recur every 8 to 15 months, and are accompanied by swarms of low-frequency tremors. We can explain the SSEs with 1 to 4 centimeters of slip along the megathrust, centered 25 to 35 kilometers (km) from the trench (4 to 10 km depth). The SSEs accommodate 30 to 55% of the plate motion, indicating frequent release of accumulated strain near the trench.

[Duplication of the superior vena cava and other malformations discovered at insertion of a port-a-cath]. / Cathéter de chambre implantable: un curieux trajet.

We report a clinical case of a persistent left superior vena cava discovered in a 50-year-old female patient when a port-a-cath was inserted. This already seldom malformation was associated with an arteria lusoria and polysplenia with left inferior vena cava with hemiazygos continuation, right-sided stomach, short pancreas, preduodenal portal vein and intestinal malrotation, but without any cardiac abnormalities.

[Unilateral hyperlucent lung induced by a carcinoid tumor: comments on the differential diagnosis and mechanisms of hypoperfusion]. / A propos d'un cas de poumon clair unilatéral induit par une tumeur carcinoïde.

We report the case of a 35-year-old woman in whom a systematic thoracic x-ray led to the diagnosis of unilateral hyperlucent lung due to a carcinoid tumor obstructing the main left bronchus almost completely. Injected computed tomography permitted diagnosis of left lung hypoperfusion and visualization of the tumor. After enlarged inferior left lobar resection, normal perfusion was observed six months later on the isotopic lung perfusion scan. Other reported causes of unilateral hyperlucent lung are discussed as well as pathophysiological mechanisms of lung hypoperfusion and hypoxic vasoconstriction.

Critically pressured free-gas reservoirs below gas-hydrate provinces.

Palaeoceanographic data have been used to suggest that methane hydrates play a significant role in global climate change. The mechanism by which methane is released during periods of global warming is, however, poorly understood. In particular, the size and role of the free-gas zone below gas-hydrate provinces remain relatively unconstrained, largely because the base of the free-gas zone is not a phase boundary and has thus defied systematic description. Here we evaluate the possibility that the maximum thickness of an interconnected free-gas zone is mechanically regulated by valving caused by fault slip in overlying sediments. Our results suggest that a critical gas column exists below most hydrate provinces in basin settings, implying that these provinces are poised for mechanical failure and are therefore highly sensitive to changes in ambient conditions. We estimate that the global free-gas reservoir may contain from one-sixth to two-thirds of the total methane trapped in hydrate. If gas accumulations are critically thick along passive continental slopes, we calculate that a 5 degrees C temperature increase at the sea floor could result in a release of approximately 2,000 Gt of methane from the free-gas zone, offering a mechanism for rapid methane release during global warming events.