Bubble Entrainment, Spray and Splashing at Hydraulic Jumps

The sudden transition from a high-velocity, supercritical open channel flow into a slow-moving sub-critical flow is a hydraulic jump. Such a flow is characterised by a sudden rise of the free-surface, with some strong energy dissipation and air entrainment, waves and spray. New two-phase flow measurements were performed in the developing flow region using a large-size facility operating at large Reynolds numbers. The experimental results demonstrated the complexity of the flow with a developing mixing layer in which entrained bubbles are advected in a high shear stress flow. The relationship between bubble count rates and void fractions was non-unique in the shear zone, supporting earlier observations of some form of double diffusion process between momentum and air bubbles. In the upper region, the flow consisted primarily of water drops and packets surrounded by air. Visually significant pray and splashing were significant above the jump roller. The present study is the first comprehensive study detailing the two-phase flow properties of both the bubbly and spray regions of hydraulic jumps, a first step towards understanding the interactions between bubble entrainment and droplet ejection processes

Hydraulic jumps: Turbulence and air bubble entrainment

A free-surface flow can change from a supercritical to subcritical flow with a strong dissipative phenomenon called a hydraulic jump. Herein the progress and development in turbulent hydraulic jumps are reviewed with a focus on hydraulic jumps operating at large Reynolds numbers typically encountered in natural streams and hydraulic structures. The key features of the turbulent hydraulic jumps are the highly turbulent flow motion associated with some intense air bubble entrainment at the jump toe. The state-of-the-art on the topic is discussed based upon recent theoretical analyses and physical data

Ageing, chronic alcohol consumption and folate are determinants of genomic DNA methylation, p16 promoter methylation and the expression of p16 in the mouse colon

Older age, dietary folate and chronic alcohol consumption are important risk factors for the development of colon cancer. The present study examined the effects of ageing, folate and alcohol on genomic and p16-specific DNA methylation, and p16 expression in the murine colon. Old (aged 18 months; n 70) and young (aged 4 months; n 70) male C57BL/6 mice were pair-fed either a Lieber-DeCarli liquid diet with alcohol (18 % of energy), a Lieber-DeCarli diet with alcohol (18 %) and reduced folate (0\ub725 mg folate/l) or an isoenergetic control diet (0\ub75 mg folate/l) for 5 or 10 weeks. Genomic DNA methylation, p16 promoter methylation and p16 gene expression were analysed by liquid chromatography\u2013MS, methylation-specific PCR and real-time RT-PCR, respectively. Genomic DNA methylation was lower in the colon of old mice compared with young mice (P < 0\ub702) at 10 weeks. Alcohol consumption did not alter genomic DNA methylation in the old mouse colon, whereas it tended to decrease genomic DNA methylation in young mice (P = 0\ub708). p16 Promoter methylation and expression were higher in the old mouse colon compared with the corresponding young groups. There was a positive correlation between p16 promoter methylation and p16 expression in the old mouse colon (P < 0\ub702). In young mice the combination of alcohol and reduced dietary folate led to significantly decreased p16 expression compared with the control group (P < 0\ub702). In conclusion, ageing and chronic alcohol consumption alter genomic DNA methylation, p16 promoter methylation and p16 gene expression in the mouse colon, and dietary folate availability can further modify the relationship with alcohol in the young mouse

EGR2 gene-linked hereditary neuropathies present with a bimodal age distribution at symptoms onset.

Mutations in the Early-Growth Response 2 (EGR2) gene cause various hereditary neuropathies, including demyelinating Charcot-Marie-Tooth (CMT) disease type 1D (CMT1D), congenital hypomyelinating neuropathy type 1 (CHN1), Déjerine-Sottas syndrome (DSS), and axonal CMT (CMT2). In this study, we identified 14 patients with heterozygous EGR2 mutations diagnosed between 2000 and 2022. Mean age was 44 years (15-70), 10 patients were female (71%), and mean disease duration was 28 years (1-56). Disease onset was before age 15 years in nine cases (64%), after age 35 years in four cases (28%), and one patient aged 26 years was asymptomatic (7%). All symptomatic patients had pes cavus and distal lower limbs weakness (100%). Distal lower limbs sensory symptoms were observed in 86% of cases, hand atrophy in 71%, and scoliosis in 21%. Nerve conduction studies showed a predominantly demyelinating sensorimotor neuropathy in all cases (100%), and five patients needed walking assistance after a mean disease duration of 50 years (47-56) (36%). Three patients were misdiagnosed as inflammatory neuropathy and treated with immunosuppressive drugs for years before diagnosis was corrected. Two patients presented with an additional neurologic disorder, including Steinert's myotonic dystrophy and spinocerebellar ataxia (14%). Eight EGR2 gene mutations were found, including four previously undescribed. Our findings demonstrate EGR2 gene-related hereditary neuropathies are rare and slowly progressive demyelinating neuropathies with two major clinical presentations, including a childhood-onset variant and an adult-onset variant which may mimic inflammatory neuropathy. Our study also expands the genotypic spectrum of EGR2 gene mutations

Anti-disialosyl-immunoglobulin M chronic autoimmune neuropathies: a nationwide multicenter retrospective study.

In this retrospective study involving 14 university hospitals from France and Switzerland, the aim was to define the clinicopathological features of chronic neuropathies with anti-disialosyl ganglioside immunoglobulin M (IgM) antibodies (CNDA). Fifty-five patients with a polyneuropathy evolving for more than 2 months and with at least one anti-disialosyl ganglioside IgM antibody, that is, anti-GD1b, -GT1b, -GQ1b, -GT1a, -GD2 and -GD3, were identified. Seventy-eight percent of patients were male, mean age at disease onset was 55 years (30-76) and disease onset was progressive (82%) or acute (18%). Patients presented with limb sensory symptoms (94% of cases), sensory ataxia (85%), oculomotor weakness (36%), limb motor symptoms (31%) and bulbar muscle weakness (18%). Sixty-five percent of patients had a demyelinating polyradiculoneuropathy electrodiagnostic profile and 24% a sensory neuronopathy profile. Anti-GD1b antibodies were found in 78% of cases, whilst other anti-disialosyl antibodies were each observed in less than 51% of patients. Other features included nerve biopsy demyelination (100% of cases), increased cerebrospinal fluid protein content (75%), IgM paraprotein (50%) and malignant hemopathy (8%). Eighty-six percent of CNDA patients were intravenous immunoglobulins-responsive, and rituximab was successfully used as second-line treatment in 50% of cases. Fifteen percent of patients had mild symptoms and were not treated. CNDA course was progressive (55%) or relapsing (45%), and 93% of patients still walked after a mean disease duration of 11 years. Chronic neuropathies with anti-disialosyl ganglioside IgM antibodies have a recognizable phenotype, are mostly intravenous immunoglobulins-responsive and present with a good outcome in a majority of cases

SORD-related peripheral neuropathy in a French and Swiss cohort: Clinical features, genetic analyses, and sorbitol dosages.

Biallelic variants in SORD have been reported as one of the main recessive causes for hereditary peripheral neuropathies such as Charcot-Marie-Tooth disease type 2 (CMT2) and distal hereditary motor neuropathy (dHMN) resulting in lower limb (LL) weakness and muscular atrophy. In this study, phenotype and genotype landscapes of SORD-related peripheral neuropathies were described in a French and Swiss cohort. Serum sorbitol dosages were used to classify SORD variants. Patients followed at neuromuscular reference centres in France and Switzerland were ascertained. Sanger sequencing and next generation sequencing were performed to sequence SORD, and mass spectrometry was used to measure patients' serum sorbitol. Thirty patients had SORD peripheral neuropathy associating LL weakness with muscular atrophy, foot deformities (87%), and sometimes proximal LL weakness (20%) or distal upper limb weakness (50%). Eighteen had dHMN, nine had CMT2, and three had intermediate CMT. Most of them had a mild or moderate disease severity. Sixteen carried a homozygous c.757delG (p.Ala253Glnfs*27) variant, and 11 carried compound heterozygous variants, among which four variants were not yet reported: c.403C &gt; G, c.379G &gt; A, c.68_100 + 1dup, and c.850dup. Two unrelated patients with different origins carried a homozygous c.458C &gt; A variant, and one patient carried a new homozygous c.786 + 5G &gt; A variant. Mean serum sorbitol levels were 17.01 mg/L ± 8.9 SD for patients carrying SORD variants. This SORD-inherited peripheral neuropathy cohort of 30 patients showed homogeneous clinical presentation and systematically elevated sorbitol levels (22-fold) compared to controls, with both diagnostic and potential therapeutic implications

Adult-onset genetic leukoencephalopathies: a MRI pattern-based approach in a comprehensive study of 154 patients

Inherited white matter diseases are rare and heterogeneous disorders usually encountered in infancy. Adult-onset forms are increasingly recognized. Our objectives were to determine relative frequencies of genetic leukoencephalopathies in a cohort of adult-onset patients and to evaluate the effectiveness of a systematic diagnostic approach. Inclusion criteria of this retrospective study were: (i) symmetrical involvement of white matter on the first available brain MRI; (ii) age of onset above 16 years. Patients with acquired diseases were excluded. Magnetic resonance imaging analysis identified three groups (vascular, cavitary and non-vascular/non-cavitary) in which distinct genetic and/or biochemical testing were realized. One hundred and fifty-four patients (male/female = 60/94) with adult-onset leukoencephalopathies were identified. Mean age of onset was 38.6 years. In the vascular group, 41/55 patients (75%) finally had a diagnosis [including CADASIL (cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy, n = 32) and COL4A1 mutation, n = 7]. In the cavitary group, 13/17 (76%) patients had a diagnosis of EIF2B-related disorder. In the third group (n = 82), a systematic biological screening allowed a diagnosis in 23 patients (28%) and oriented direct genetic screening identified 21 additional diseases (25.6%). Adult-onset genetic leukoencephalopathies are a rare but probably underestimated entity. Our study confirms the use of a magnetic resonance imaging-based classification with a final diagnosis rate of 64% (98/154) cases

Analysis of muscle magnetic resonance imaging of a large cohort of patient with VCP-mediated disease reveals characteristic features useful for diagnosis

BackgroundThe diagnosis of patients with mutations in the VCP gene can be complicated due to their broad phenotypic spectrum including myopathy, motor neuron disease and peripheral neuropathy. Muscle MRI guides the diagnosis in neuromuscular diseases (NMDs); however, comprehensive muscle MRI features for VCP patients have not been reported so far.MethodsWe collected muscle MRIs of 80 of the 255 patients who participated in the “VCP International Study” and reviewed the T1-weighted (T1w) and short tau inversion recovery (STIR) sequences. We identified a series of potential diagnostic MRI based characteristics useful for the diagnosis of VCP disease and validated them in 1089 MRIs from patients with other genetically confirmed NMDs.ResultsFat replacement of at least one muscle was identified in all symptomatic patients. The most common finding was the existence of patchy areas of fat replacement. Although there was a wide variability of muscles affected, we observed a common pattern characterized by the involvement of periscapular, paraspinal, gluteal and quadriceps muscles. STIR signal was enhanced in 67% of the patients, either in the muscle itself or in the surrounding fascia. We identified 10 diagnostic characteristics based on the pattern identified that allowed us to distinguish VCP disease from other neuromuscular diseases with high accuracy.ConclusionsPatients with mutations in the VCP gene had common features on muscle MRI that are helpful for diagnosis purposes, including the presence of patchy fat replacement and a prominent involvement of the periscapular, paraspinal, abdominal and thigh muscles.Neurological Motor Disorder