A massive rock and ice avalanche caused the 2021 disaster at Chamoli, Indian Himalaya.

On 7 February 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. More than 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27 × 106 cubic meters of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders greater than 20 meters in diameter and scoured the valley walls up to 220 meters above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.

Thread-based microfluidics: Flow patterns in homogeneous and heterogeneous microfiber bundles.

Thread-based microfluidics has recently seen considerable developments in the domain of portable diagnostic systems, smart bandages and tissue engineering. Similarly to paper-based microfluidics, thread-based microfluidics uses the wicking of fibers to move fluids. It has the advantage of confining and guiding the fluid along the yarns in a one, two or three dimensional space. A global approach to the motion of fluids in yarns and fiber bundles has already been reported in the literature based on the Lucas-Washburn-Rideal law. However no detailed investigation of the flow pattern inside the bundle has been conducted, depending on the internal structure of the bundle. Especially when the bundle possesses heterogeneous wetting properties, such as two different wetting regions interior and exterior, different flow patterns may exist. In this work, we perform a theoretical and numerical analysis of the different flow regimes for homogenous and heterogeneous fiber bundles. It is demonstrated that a limited number of fibers is sufficient for thread-based capillary flows, and that a caging of the flow can be achieved by realizing a lyophobic envelope.

On the halt of spontaneous capillary flows in diverging open channels.

Due to their compactness and independence of exterior energy sources, capillary microsystems are increasingly used in many different scientific domains, from biotechnology to medicine and biology, chemistry, energy and space. Obtaining a capillary flow depends on channel geometry and contact angle. A general condition for the establishment of a spontaneous capillary flow in a uniform cross section channel has already been derived from Gibbs free energy. In this work, we consider spontaneous capillary flows (SCF) in diverging open rectangular channels and suspended channels, and we show that they do not flow indefinitely but stop at some location in the channel. In the case of linearly diverging open channels, we derive the expression that determines the location where the flow stops. The theoretical approach is verified by using the Surface Evolver numerical program and is checked by experiments. The approach is extended to sudden enlargements, and it is shown that the enlargements can act as stop and trigger valves.

Simultaneous CT angiography and whole-body CT is an effective imaging approach before multiorgan retrieval.

PURPOSE: To assess the role of whole-body computed tomography (CT) for determining morphological suitability before multiorgan retrieval (MOR) in brain dead patients. MATERIALS AND METHODS: Fifty-one clinically brain dead patients (21 women, 30 men; mean age 61 year±15) were included in this prospective, single center study. All patients had CT angiography of the brain and whole-body CT examination. CT images were evaluated for the presence of morphological abnormalities of lungs, liver and other abdominal organs and presence of vascular anatomical variants. The results of CT examinations were compared to intraoperative findings observed during organ harvesting and/or the results of histopathological analysis of biopsy specimens. The impact of whole-body CT examination on the harvesting process was evaluated. RESULTS: Ninety-five percent of vascular anatomical variants that were found intraoperatively were depicted on CT. CT density measurements predicted surgical finding of steatosis in 80% of patients. Whole-body CT changed the MOR strategy in 21/51 patients (41%) including 3 MOR cancellations and 8 grafts refusals, whereas organ harvesting was continued in 10 patients after histopathological analysis was performed. CONCLUSION: Selection of potential graft donors using whole-body CT is reliable and improves graft selection during MOR.

Atmospheric drying as the main driver of dramatic glacier wastage in the southern Indian Ocean.

The ongoing retreat of glaciers at southern sub-polar latitudes is particularly rapid and widespread. Akin to northern sub-polar latitudes, this retreat is generally assumed to be linked to warming. However, no long-term and well-constrained glacier modeling has ever been performed to confirm this hypothesis. Here, we model the Cook Ice Cap mass balance on the Kerguelen Islands (Southern Indian Ocean, 49°S) since the 1850s. We show that glacier wastage during the 2000s in the Kerguelen was among the most dramatic on Earth. We attribute 77% of the increasingly negative mass balance since the 1960s to atmospheric drying associated with a poleward shift of the mid-latitude storm track. Because precipitation modeling is very challenging for the current generation of climate models over the study area, models incorrectly simulate the climate drivers behind the recent glacier wastage in the Kerguelen. This suggests that future glacier wastage projections should be considered cautiously where changes in atmospheric circulation are expected.

Surface-tension driven open microfluidic platform for hanging droplet culture.

The hanging droplet technique for three-dimensional tissue culture has been used for decades in biology labs, with the core technology remaining relatively unchanged. Recently microscale approaches have expanded the capabilities of the hanging droplet method, making it more user-friendly. We present a spontaneously driven, open hanging droplet culture platform to address many limitations of current platforms. Our platform makes use of two interconnected hanging droplet wells, a larger well where cells are cultured and a smaller well for user interface via a pipette. The two-well system results in lower shear stress in the culture well during fluid exchange, enabling shear sensitive or non-adherent cells to be cultured in a droplet. The ability to perform fluid exchanges in-droplet enables long-term culture, treatment, and characterization without disruption of the culture. The open well format of the platform was utilized to perform time-dependent coculture, enabling culture configurations with bone tissue scaffolds and cells grown in suspension. The open nature of the system allowed the direct addition or removal of tissue over the course of an experiment, manipulations that would be impractical in other microfluidic or hanging droplet culture platforms.

Gradient generation platforms: new directions for an established microfluidic technology.

Microscale platforms are enabling for cell-based studies as they allow the recapitulation of physiological conditions such as extracellular matrix (ECM) configurations and soluble factors interactions. Gradient generation platforms have been one of the few applications of microfluidics that have begun to be translated to biological laboratories and may become a new "gold standard". Though gradient generation platforms are now established, their full potential has not yet been realized. Here, we will provide our perspective on milestones achieved in the development of gradient generation and cell migration platforms, as well as emerging directions such as using cell migration as a diagnostic readout and attaining mechanistic information from cell migration models.

MRI and venographic aspects of pelvic venous insufficiency.

Pelvic venous insufficiency is a frequent pathology in multiparous women. Diagnosis can be made by chance or suspected in the case of symptoms suggesting pelvic congestion syndrome or atypical lower limb varicosity fed by pelvic leaks. After ultrasound confirmation, dynamic venography is the reference pretherapeutic imaging technique, searching for pelvic varicosity and possible leaks to the lower limbs. MRI is less invasive and allows a three-dimensional study of the varicosity and, with dynamic angiography, it can assess ovarian reflux. It also helps to plan or even sometimes avoid diagnostic venography.

Study of the water budget of streets: experimentation and modelling.

The study of two stretches of street during 38 months has been performed to analyze the hydrological behavior of streets during rain events. The results show that runoff coefficients are very variable and runoff losses may be important. In order to better understand this behavior, a physically based model has been used. This model, BiL, combines a porous media flow module with a surface runoff module. The lateral runoff transfer in the lateral gutter is approximated by the Muskingum model. Evaporation is simulated by an adaptation of the Penman method. A sensitivity study shows that the model is mainly sensitive to saturated hydraulic conductivity of the asphalt pavement and to the storage capacity. The comparison of simulated and observed data gives good results for the runoff outflow at a 3 minutes time step. Nevertheless, the simulation results are less encouraging for the runoff coefficient. This study of the water budget of two street stretches during a time period of 38 months indicates that the infiltration and evaporation represent between 20 and 30% of rain.

Nonlocal thermodynamic equilibrium self-consistent average-atom model for plasma physics.

A time-dependent collisional-radiative average-atom model is presented to study statistical properties of highly charged ion plasmas in off-equilibrium conditions. The time evolution of electron populations and the electron covariance matrix is obtained as approximate solutions of a master equation. Atomic structure is described either with a screened-hydrogenic model including l splitting, or by calculating one-electron states in a self-consistent average-atom potential. Collisional and radiative excitation/deexcitation and ionization/recombination rates, as well as autoionization and dielectronic recombination rates, are formulated within the average-configuration framework. Local thermodynamic equilibrium is obtained as a specific steady-state solution. The influence of atomic structure and the role of autoionization and dielectronic recombination processes are studied by calculating steady-state average ionization and ionization variance of hot plasmas with or without radiation field.

Diagnostic utility of somatosensory evoked potentials (SEPs) in presurgical assessment of cervical spondylotic myelopathy.

Median and tibial nerve SEPs were recorded in 27 patients with spondylotic myelopathy. SEP data were compared with clinical and MRI data. SEPs were abnormal in all but five patients. Segmental dysfuction of the cervical cord was observed in 12 patients (45%), whereas abnormality of dorsal column conduction was observed in 10 (37%) and 16 (59.3%) patients after median and tibial nerve stimulation, respectively. No clear correlation was found between the severity of MRI abnormalities and that of clinical presentation or SEP abnormalities. However, there was no patient with normal SEPs and severe MRI abnormalities, including narrowing of cervical cord diameter or impingement of the cervical cord or intramedullary T2 signal hyper intensity. Conversely, 8 of the 13 patients with no evidence of cord narrowing or T2 signal abnormality showed abnormal SEPs. This divergence between SEP and MRI data suggests that SEP recording should be included in presurgical assessment of these patients, especially those without clear MRI evidence of cervical cord compression.

Facial motor responses evoked by direct electrical stimulation of the trigeminal root. Localizing value for radiofrequency thermorhizotomy.

In Sweet's description of RF-thermocoagulation for trigeminal neuralgia, the trigeminal nerve was stimulated at 50 c/s to evoke paraesthesias, in order to check the electrode location before the thermolesion is made. In 1979, we changed the frequency to 5 c/s, so as to produce in addition twitches in the masticatory muscles (in stead of the less detectable tetanization produced by 50 c/s stimulation). Since then, we started to observe, also, twitches in the muscles innervated by the facial nerve. These twitches were not always in the Orbicularis oculi (which corresponds to the classical blink reflex), but also in the lower facial muscles. Such clinically observable evoked motor responses (EMR)-which had not been reported before--were noticed in 44% of the 459 procedures performed from 1979 to 1988. When EMR were present, the threshold to evoke paraesthesias before thermolesion, and the duration of the thermolesion for obtaining a marked hypoaesthesia covering the entire painful territory, were significantly lower, respectively p < 0.01 and p < 0.001, than when EMR were absent. This indicates that the electrode was closer to the nerve when EMR were present. As a probable consequence, recurrence of pain was significantly lower in the EMR (+) group: 1.4%, than in the EMR (-) group: 5.8% (p < 0.05). The twitches corresponded to the territory of the evoked paraesthesias in 95%, and to the hypoaesthetic area created by the thermolesion in 96%. So, getting EMR in the territory of the pain can be a helpful indicator for an accurate location of the electrode in the trigeminal root, according to its somatotopic organization. These EMR are hypothesized to be due to a trigemino-facial reflex. A preliminary intra-operative EMG study clearly shows that for EMR in the upper part of the face we are dealing with blink-like reflexes, whilst for EMR in the lower face, mechanisms still remain unclear and need further study to be understood.

[Idiopathic cranial polyneuropathies]. / Polyneuropathies crâniennes idiopathiques.

A series of 43 cases with multiple cranial nerve deficits was collected between 1972 and 1990. No diagnosis was established in 15 cases. The facial and the trigeminal nerves were most frequently affected. In 10 cases, a monophasic course was observed usually with recovery. Recurrence was present in 5 cases. An inflammatory mechanism was likely in 10 cases. Nosological relations between these cases and either Bell's palsy (idiopathic facial paralysis) or Tolosa-Hunt's syndrome are discussed.

[Juvenile arteriosclerotic leukoencephalopathy: anatomoclinical study of a case]. / Leucoencéphalopathie artériopathique juvénile: étude anatomoclinique d'un cas.

A 34-year old right-handed man was suffering from recurrent cerebro-vascular insults. CT-scans revealed several subcortical lacunar infarcts, and leukoaraïosis. Arteriography of the left and the right carotid arteries was performed respectively on the 4th and the 9th year of the disease, and did not elicit significant extracranial and intracranial vascular lesions. There were no arguments in favor of infectious, inflammatory, or auto-immune vascular diseases. The patient had tardive hypertension and dementia, and died at the age of 44. Pathological findings, limited to the brain and cervical spinal cord, revealed numerous ischemic lacunar infarcts. Histological lesions were consistent with the diagnosis of arteriosclerotic leukoencephalopathy. There were oedema, palor, and loss of myelin in the white matter, and nonspecific diffuse arteriosclerotic lesions that were particularly pronounced in the intimal part of the arterial wall. No inflammatory process nor amyloid deposits were found. Despite the onset of the disease in a young adult and the late occurrence of hypertension, our case report shares most of the pathological features of the Binswanger's type of arteriosclerotic encephalopathy.