An electrodeposition model with surface relaxation predicts temperature and current effects in compact and dendritic film morphologies.

We study a thin-film electrodeposition model that represents the relaxation of the deposited material by adatom diffusion on quenched crystal topographies and considers simple mechanisms of cation flux in the electrolyte. The results of numerical simulations with collimated flux and a rapid cation reduction in contact with the deposit relate the surface roughness and the adatom hop numbers with two model parameters. A comparison with the results of a collective diffusion model for vapor deposition shows differences in the surface morphologies but similarities in scaling relations, which suggest thermally activated (Arrhenius) forms for the parameters of the electrodeposition model and relate one of them to the applied current. Simulations with purely diffusive cation flux and possible pore formation in simple cubic lattices show the growth of self-organized structures with leaf shapes (dendrites) above a compact layer that covers the flat electrode. The thickness of this layer and the average dendrite size also obey scaling relations in terms of the model parameters, which predict that both sizes decrease with the applied current, in agreement with recent experimental studies. Under all flux conditions, an increase in adatom diffusivity with temperature implies an increase in the average sizes of low-energy surface configurations, independently of their particular shapes. Finally, we note that a previously proposed model for electrodeposition produced similar morphologies, but the quantitative relations for the characteristic sizes differ from those of the present model, which also advances with a consistent interpretation of temperature effects.

Verbal instruction to obtain voluntary pelvic floor muscle contraction: Acceptability, and understanding.

PURPOSE: The aim of this study was to describe verbal instructions used to obtain a voluntary pelvic floor muscle contraction and to evaluate their understanding and acceptability. METHODS: This prospective study led in two phases. A questionnaire was submitted to experts to collect the most frequently used instructions to obtain a PFMC. Then a questionnaire was submitted to subjects in order to: estimate the pelvic floor anatomical knowledge; estimate understanding and acceptability of these instructions; select the best instruction. RESULTS: First phase: 46 experts proposed 356 instructions. Forty-four percent were functional instructions ("hold a gas"), 40% anatomical ("squeeze your anus") and 16% allied both. Fifteen instructions for the women and 11 for the men were selected. Second phase: 33 subjects completed the questionnaire. More than 75% had correct answers for anatomical knowledge. The instructions judged by the subjects as the most adapted to obtain a PFMC were: "contract the anus", "do as if you wanted to hold a strong desire to void". The items including "perineum" or "vagina" were less understood. CONCLUSIONS: The more understandable and acceptable instruction to assess the PFMC is the association of two simple instructions: one anatomical and one functional. LEVEL OF EVIDENCE: 4.

Short-term reproducibility of cystometry in multiple sclerosis patients.

OBJECTIVE: To assess the reproducibility of detrusor activity cystometric pattern in multiple sclerosis (MS) patients, which is poorly documented in the medical literature, by means of successive filling. METHODS: We conducted a prospective study in MS patients; cystometry was repeated twice at 5minutes of interval if a detrusor overactivity before 300mL of filling was observed. Thus, 3 successive cystometries were analysed. The following characteristics were recorded: detrusor maximum pressure (Pmax), volume at the first involuntary detrusor contraction (IDC), maximum cystometric capacity (MCC), pressure at the first IDC, the existence of an overactive detrusor classified as phasic or terminal. RESULTS: We included 31 patients (19 women and 12 men); only 6 patients were naïve-treatment, the mean EDSS was: 5.3 (±1.6) and the mean age was 48.4 (±12.5) years. All the patients had an overactive detrusor for each cystometry. The reproducibility was good for all the parameters (range ICC between 0.7 and 0.83). CONCLUSION: Quantitative and qualitative cystometric data have a good reproducibility in MS patients with detrusor overactivity before 300mL of filling. LEVEL OF PROOF: 3.

Prevalence of comorbidities in multiple sclerosis patients with neurogenic bladder.

AIMS: The aim of this study was to define the prevalence of comorbidities among multiple sclerosis patients with lower urinary tract symptoms. METHODS: A retrospective study of data collected prospectively from January 2000 to March 2016 was carried out using a database. Comorbidities were divided into several classes according to the International Classification of Diseases (ICD-10). RESULTS: One hundred and fifty-five patients were included. All had a neurogenic bladder with 150 (96%) overactive bladder. EDSS score was≥6 in 44 patients (28%). Comorbidities were present in 79 (50,9%) and the most frequent ones were cardiovascular (14,2%), endocrinological (10,3%), urological (8,4%), abdominal (7,7%). Overweight (BMI≥25) was observed in 63 (40%). A strict relationship was found for BMI and stress urinary incontinence (P<0.001) as well as voiding dysfunction (P=0.003) without significant association for BMI and overactive bladder. CONCLUSION: Prevalence of comorbidities is important in MS (more than 50%). A significant association is found between overweight, stress urinary incontinence and voiding dysfunction. Knowledge of these comorbidities in MS is important since the presence of these urinary symptoms not related to neurogenic bladder must lead to a specific treatment. LEVEL OF EVIDENCE: 3.

[Effects of attention and desire to void on sensory evoked cortical potentials following perineal stimulation]. / Modification de la structuration des potentiels évoqués cérébraux sensoriels par stimulation périnéale lors d'une focalisation attentionnelle sur le besoin d'uriner.

OBJECTIVE: Cortical somatosensory evoked potentials (SEP) are usually used to test the integrity of lemniscal pathways and thus provide arguments for the neurogenic etiology of sensory symptoms. For example, PES by perineal stimulation (SEP-P) has been shown to be altered in incontinence or neurogenic sexual dysfunction. We wanted to verify the integrity, structure and amplitude of far-field responses of PES-P in two conditions, the first without feeling the need to urinate (S0), the second with urgency (US). METHODS: SEP-P were recorded in ten patients without neurological pathology in both conditions S0 and US after stimulation of the dorsal nerve of the penis/clitoris. Three consecutive responses each averaged over 1000 passages at a frequency of 3Hz were recorded. RESULTS: Seven men and 3 women were included. All patients had normal SEP-P in terms of amplitude and latency of the P40 complex and fully reproducible especially for late responses. These early P40 responses were identical in both S0 and US states. Conversely, the far-field potentials, i.e. the late responses, were different in the two states, with a significant decrease (P<0.008 paired T-test) in the amplitude of cortical responses in the US state. CONCLUSION: We observe that the late components of SEP-P were altered by the need to urinate urgently with sustained and selective attention to this need. These late components of SEP-P could be useful to better specify the attentional mechanisms involved in the continence-voiding cycle and to specify pathological sensory dysfunctions (urgency, painful bladder, frequency…). LEVEL OF EVIDENCE: 4.

[Anal tone: Physiology, clinical and instrumental characteristics]. / Tonus anal : déterminant physiologique, évaluation clinique et paraclinique, caractéristique pathologique.

INTRODUCTION: The anal tone allows the maintenance of anorectal continence. Its regulation depends on spinal segmental mechanisms under supra-sacral control. MATERIAL AND METHODS: A systematic review was performed using Medline database, according to PRISMA methodology, using following keywords anal tone ; anal sphincter ; anorectal function ; reflex ; digital rectal examination. RESULTS: Anal hypertonia is an increase in the muscle's resistance to passive stretching. Muscular hypotonia is a decrease in muscle tone. It is associated with a decrease in resistance to passive mobilization. It is not possible to quantify the prevalence of anal tone alterations in the general population and in specific pathological conditions (urinary disorders, neurogenic or non-neurogenic anorectal disorders). In case of hypotonia, most often due to a lower motor neuron lesion, fecal incontinence may occur. Hypertonia (anal sphincter overactivity) is not always due to perineal spasticity. Indeed, in the majority of the cases, the cause of this anal hypertonia in a neurologic context, can be secondary to an upper motor neuron disease due to spinal or encephalic lesion, leading to recto-anal dyssynergia, giving distal constipation. In another way, this anal hypertonia can be purely behavioral, with no direct pathological significance. The evaluation of anal tone is clinical with validated scores but whose sensitivity is not absolute, and instrumental with, on the one hand, the measurement of anal pressure in manometry and, on the other hand, electrophysiological testing which still require validation in this indication. CONCLUSION: Anal tone assessment is of interest in clinical practice because it gives diagnostic arguments for the neurological lesion and its level, in the presence of urinary or anorectal symptoms.

Emptying cystometry: A feasibility and validation pilot study on female patients.

INTRODUCTION: To assess the feasibility and the accuracy of emptying cystometry in order to simplify the manometric follow-up of overactive detrusor in neurological patients under anticholinergic or botulinum toxin injections. MATERIAL: Female patients with a stable detrusor underwent both a conventional cystometry and sequential measurements of bladder pressure during emptying (emptying cystometry). At the end of the standard cystometry, a CH12 urinary catheter was introduced in the bladder and was connected to a three-way stopcock. The second way of the stopcock permitted the emptying. The third way of the stopcock was connected to a vertical graduated tube to measure the bladder pressure each 50mL during the bladder emptying. RESULTS: Eleven female patients were included (mean age: 59.4years). Nine patients (82%) had neurogenic bladder. Mean cystometric capacity was 439mL (SD: 35mL). During the emptying cystometry, 8 to 10 measures were taken (mean: 9.4). The mean detrusor pressure was 1.7cmH2O (SD 2.1) for the filling cystometry and 2.3cmH2O (SD: 2.7) for the emptying cystometry. The agreement between the detrusor pressure between the two cystometries was good with intra-class correlation coefficient at 0.66 [0.48-0.77] - and the correlation was high (r=0.7; P<0.000001). CONCLUSION: In a small, selected sample of patients, emptying cystometry provides similar results of detrusor pressure to filling cystometry. This technique could constitute a home monitoring of bladder pressures in a selected population of patients with intermittent catheterization in whom a manometric follow-up of detrusor overactivity is required. LEVEL OF EVIDENCE: 4.

SEX DIFFERENCES ON THE WISC-III AMONG CHILDREN IN SUDAN AND THE UNITED STATES.

The sex differences on the WISC-III are reported for the thirteen subtests, the Verbal and Performance IQs, the four Index IQs and the Full Scale IQs in Sudan and the United States. The sex differences are closely similar in the two samples with a correlation of 0.878 (p<0.001) for the thirteen subtests. Males obtained significantly higher Full Scale IQs in the two samples of 0.23d and 0.11d, respectively.

Dimensional crossover in Kardar-Parisi-Zhang growth.

Two-dimensional (2D) Kardar-Parisi-Zhang (KPZ) growth is usually investigated on substrates of lateral sizes L_{x}=L_{y}, so that L_{x} and the correlation length (ξ) are the only relevant lengths determining the scaling behavior. However, in cylindrical geometry, as well as in flat rectangular substrates L_{x}≠L_{y} and, thus, the surfaces can become correlated in a single direction, when ξ∼L_{x}≪L_{y}. From extensive simulations of several KPZ models, we demonstrate that this yields a dimensional crossover in their dynamics, with the roughness scaling as W∼t^{ß_{2D}} for t≪t_{c} and W∼t^{ß_{1D}} for t≫t_{c}, where t_{c}∼L_{x}^{1/z_{2D}}. The height distributions (HDs) also cross over from the 2D flat (cylindrical) HD to the asymptotic Tracy-Widom Gaussian orthogonal ensemble (Gaussian unitary ensemble) distribution. Moreover, 2D to one-dimensional (1D) crossovers are found also in the asymptotic growth velocity and in the steady-state regime of flat systems, where a family of universal HDs exists, interpolating between the 2D and 1D ones as L_{y}/L_{x} increases. Importantly, the crossover scalings are fully determined and indicate a possible way to solve 2D KPZ models.

[Comparison between autonomic nervous system cardiovascular tests (ANSCVT) and lacrymal and or salivary secretion tests (LSST) in overactive bladder syndrome and voiding dysfunction]. / Apport des tests sécrétoires dans la mise en évidence d'une dysrégulation végétative au cours des troubles vésicosphinctériens idiopathiques. Comparaison avec les tests cardiovasculaires de la fonction autonome.

PURPOSE: To compare autonomic nervous system cardiovascular tests (ANSCVT) and lacrymal and or salivary secretion tests (LSST). METHOD: One hundred and twenty-four patients (57 females, 67 males, mean age 45) with lower urinary tract symptoms (overactive bladder syndrome or voiding dysfunction) without neurogenic or urological causes, were included. Urodynamic was performed in all the patients with LSST (saliva flowmetry-sialometry [SFS], candy weight-loss test [CWT], Schirmer test [SchT]) and ANSCVT (ratio 30:15, orthostatic hypotension analysis, deep breath test [DBT], Valsalva maneuver [VM], cold pressor test [CPT] and hand grip test [HGT]). RESULTS: In eight cases, ANSCVT were altered (four in OAB syndrome, four in voiding dysfunction). No correlation was found between positive ANSCVT and LSST (P=0.72 for CWT, P=1 for SFS, P=0.1 for SchT). In contrary, there is a significant correlation between SchT and CWT (P=0.049), but not between SchT and SFS (P=0.69) or SFS vs CWT (P=0.06). CONCLUSION: In this series LSST were not sufficient to track down autonomic nervous system alterations and ANSCVT always necessary. Autonomic dysfunctions were infrequent in OAB syndrome and "idiopathic" voiding dysfunctions (6.5%).

[Autonomic nervous system alteration in multiple sclerosis patients with urinary symptoms. Clinical, urodynamic and cardiovascular study]. / Dysautonomie et troubles urinaires au cours de la sclérose en plaques. Étude clinique, urodynamique et cardiovasculaire.

OBJECTIVE: To assess symptoms related to autonomic nervous system alteration in a population of patients suffering from multiple sclerosis (MS) and presenting with urinary symptoms. PATIENTS AND METHODS: We investigated 65 patients (mean age 47.5 years) suffering from MS, and presenting with urological dysfunction by means of symptom scores, urodynamic investigation, cardiovascular autonomic function tests (orthostatic hypotension testing, Valsalva test, deep breath test, cold pressor test) and sympathetic skin responses. RESULTS: Forty-five (69%) patients suffered from overactive bladder, 48 (73%) from voiding dysfunction, 14 (21%) from urinary retention and 13 (20%) from fecal incontinence. Urodynamic investigation demonstrated overactive detrusor in 46 (70%) cases, and underactive detrusor in four (6%) cases. Twenty-five (38%) patients had dysautonomia without correlation neither with clinical or urodynamic data, nor gravity of multiple sclerosis (EDSS). CONCLUSION: In this series, the prevalence of dysautonomia was high in patients suffering from MS and presenting with urinary disorders.

[Clinical and electrophysiological study of sensory penile alterations. A prospective study of 44 cases]. / Analyse clinique et neurophysiologique des troubles de la sensibilité pénienne. Étude prospective de 44 cas.

OBJECTIVE: To precise clinical presentations, pathophysiology and etiologies of penile sensory alteration. METHODS: Forty-four patients with penile sensory dysfunction underwent clinical and electrophysiological testing with electromyography of bulbocavernosus muscles, study of sacral reflex latencies, somatosensory cortical responses following stimulation of the dorsal nerve of the penis, sensory velocity of the dorsal nerve and pudendal nerve terminal sensory latencies. RESULTS: Penile anesthesia was observed in six (13%) patients, loss of sensibility in 34 (77%), paresthesia in four (9%). Erectile dysfunction was noted in 19 (43%) patients, hypo-orgasmia in seven (16%), cold glans penis sensation in four and loss of spatial sensation during intercourse in three (7%). Abnormalities of electrophysiological perineal testing were observed in 17 (38%) patients. In 27 (62%) cases, no alteration of electrophysiological testing was observed. In 17 (38%) patients, a specific aetiology was founded by means nerve palsy during orthopedic surgery in five cases, entrapment neuropathy following byking in nine cases, two La Peyronie diseases and one diabetes mellitus. CONCLUSION: In the current series, the prevalence of neuropathy of the dorsal nerve of the penis (that can determine a loss of sensibility) was 40%.

One-point height fluctuations and two-point correlators of (2+1) cylindrical KPZ systems.

While the one-point height distributions (HDs) and two-point covariances of (2+1) Kardar-Parisi-Zhang (KPZ) systems have been investigated in several recent works for flat and spherical geometries, for the cylindrical one the HD was analyzed for few models and nothing is known about the spatial and temporal covariances. Here, we report results for these quantities, obtained from extensive numerical simulations of discrete KPZ models, for three different setups yielding cylindrical growth. Beyond demonstrating the universality of the HD and covariances, our results reveal other interesting features of this geometry. For example, the spatial covariances measured along the longitudinal and azimuthal directions are different, with the former being quite similar to the curve for flat (2+1) KPZ systems, while the latter resembles the Airy_{2} covariance of circular (1+1) KPZ interfaces. We also argue (and present numerical evidence) that, in general, the rescaled temporal covariance A(t/t_{0}) decays asymptotically as A(x)∼x^{-λ[over ¯]} with an exponent λ[over ¯]=ß+d^{*}/z, where d^{*} is the number of interface sides kept fixed during the growth (being d^{*}=1 for the systems analyzed here). Overall, these results complete the picture of the main statistics for the (2+1) KPZ class.

Scaling of surface roughness in film deposition with height-dependent step edge barriers.

We perform kinetic Monte Carlo simulations of film growth in simple cubic lattices with solid-on-solid conditions, Ehrlich-Schwoebel (ES) barriers at step edges, and a kinetic barrier related to the hidden off-plane diffusion at multilayer steps. Broad ranges of the diffusion-to-deposition ratio R, detachment probability per lateral neighbor, ε, and monolayer step crossing probability P=exp[-E_{ES}/(k_{B}T)] are studied. Without the ES barrier, four possible scaling regimes are shown as the coverage θ increases: nearly layer-by-layer growth with damped roughness oscillations; kinetic roughening in the Villain-Lai-Das Sarma (VLDS) universality class when the roughness is W∼1 (in lattice units); unstable roughening with mound nucleation and growth, where slopes of logW×logθ plots reach values larger than 0.5; and asymptotic statistical growth with W=θ^{1/2} solely due to the kinetic barrier at multilayer steps. If the ES barrier is present, the layer-by-layer growth crosses over directly to the unstable regime, with no transient VLDS scaling. However, in simulations up to θ=10^{4} (typical of films with a few micrometers), low temperatures (small R, Îµ, or P) may suppress the two or three initial regimes, while high temperatures and P∼1 produce smooth surfaces at all thicknesses. These crossovers help to explain proposals of nonuniversal exponents in previous works. We define a smooth film thickness θ_{c} where W=1 and show that VLDS scaling at that point indicates negligible ES barriers, while rapidly increasing roughness indicates a small ES barrier (E_{ES}∼k_{B}T). θ_{c} scales as ∼exp(const×P^{2/3}) if the other parameters are kept fixed, which represents a high sensitivity on the ES barrier. The analysis of recent experimental data in the light of our results distinguishes cases where E_{ES}/(k_{B}T) is negligible, ∼1, or ≪1.

Integrated machine learning-based model and WQI for groundwater quality assessment: ML, geospatial, and hydro-index approaches.

The demands upon the arid area for water supply pose threats to both the quantity and quality of social and economic activities. Thus, a widely used machine learning model, namely the support vector machines (SVM) integrated with water quality indices (WQI), was used to assess the groundwater quality. The predictive ability of the SVM model was assessed using a field dataset for groundwater from Abu-Sweir and Abu-Hammad, Ismalia, Egypt. Multiple water quality parameters were chosen as independent variables to build the model. The results revealed that the permissible and unsuitable class values range from 36 to 27%, 45 to 36%, and 68 to 15% for the WQI approach, SVM method and SVM-WQI model respectively. Besides, the SVM-WQI model shows a low percentage of the area for excellent class compared to the SVM model and WQI. The SVM model trained with all predictors with a mean square error (MSE) of 0.002 and 0.41; the models that had higher accuracy reached 0.88. Moreover, the study highlighted that SVM-WQI can be successfully implemented for the assessment of groundwater quality (0.90 accuracy). The resulting groundwater model in the study sites indicates that the groundwater is influenced by rock-water interaction and the effect of leaching and dissolution. Overall, the integrated ML model and WQI give an understanding of water quality assessment, which may be helpful in the future development of such areas.

[Evidence of pudendal neuropathy in Proctalgia Fugax: perineal neurophysiological assessment in 55 patients]. / Proctalgies fugaces et neuropathie pudendale : étude neurophysiologique périnéale chez 55 patients.

OBJECTIVE: Proctalgia fugax (PF) is a very common condition especially in women. Causes and pathophysiological mechanisms of PF are unknown. Recently, a pudendal neuropathy was clinically suspected in women with PF. The goal of our study was to demonstrate, or not, such abnormalities by means electrophysiological testing. PATIENTS AND METHODS: Fifty-five patients with PF (45 female and 10 male, mean age 50.2 years) were evaluated. EMG testing with motor unit potential analysis of pelvic floor muscles (bulbocavernosus muscle and striated external anal sphincter), study of bulbocavernosus reflex and pudendal nerve terminal motor latencies (PNTML) were performed. RESULTS: EMG testing was altered in two males out of 10 (20%) and 29/45 females (64%). In women, denervation was found bilateral in 25/29 (86%). Sacral latency was delayed in eight out of 29 (bilateral in five cases, unilateral in three cases) and PNTML altered in 17 cases (13 bilateral alteration, four unilateral). A significant difference (P<0.002 Chi(2) test) was demonstrated between male and female concerning pelvic floor muscles denervation. CONCLUSION: Pelvic floor muscles denervation was a common feature in women suffering from PF, due to a stretch bilateral pudendal neuropathy. Distal lesions of the pudendal nerves, principally due to a stretch perineal neuropathy, can be imagined as a factor or co-factor of PF.

Kardar-Parisi-Zhang growth on square domains that enlarge nonlinearly in time.

Fundamental properties of an interface evolving on a domain of size L, such as its height distribution (HD) and two-point covariances, are known to assume universal but different forms depending on whether L is fixed (flat geometry) or expands linearly in time (radial growth). The interesting situation where L varies nonlinearly, however, is far less explored and it has never been tackled for two-dimensional (2D) interfaces. Here, we study discrete Kardar-Parisi-Zhang (KPZ) growth models deposited on square lattice substrates, whose (average) lateral size enlarges as L=L_{0}+ωt^{γ}. Our numerical simulations reveal that the competition between the substrate expansion and the increase of the correlation length parallel to the substrate, ξ≃ct^{1/z}, gives rise to a number of interesting results. For instance, when γ<1/z the interface becomes fully correlated, but its squared roughness, W_{2}, keeps increasing as W_{2}∼t^{2αγ}, as previously observed for one-dimensional (1D) systems. A careful analysis of this scaling, accounting for an intrinsic width on it, allows us to estimate the roughness exponent of the 2D KPZ class as α=0.387(1), which is very accurate and robust, once it was obtained averaging the exponents for different models and growth conditions (i.e., for various γ^{'}s and ω^{'}s). In this correlated regime, the HDs and covariances are consistent with those expected for the steady-state regime of the 2D KPZ class for flat geometry. For γ≈1/z, we find a family of distributions and covariances continuously interpolating between those for the steady-state and the growth regime of radial KPZ interfaces, as the ratio ω/c augments. When γ>1/z the system stays forever in the growth regime and the HDs always converge to the same asymptotic distribution, which is the one for the radial case. The spatial covariances, on the other hand, are (γ,ω)-dependent, showing a trend towards the covariance of a random deposition in enlarging substrates as the expansion rate increases. These results considerably generalize our understanding of the height fluctuations in 2D KPZ systems, revealing a scenario very similar to the one previously found in the 1D case.

Fecal incontinence subtype assessment (FI-SA): A new tool to distinguish among subtypes of fecal incontinence in a neurogenic population.

INTRODUCTION: Two subtypes of fecal incontinence (FI) are defined in the literature (urge and passive FI). The pertinence of this classification is unknown due to conflicting findings and heterogeneity of definitions. However, no questionnaire is available to clearly classify patients among subtypes. The objective of the present study was to develop and validate a new tool (Fecal incontinence subtype assessment, FI-SA) in order to better classify patients among the different subtypes of FI. METHODS: A prospective monocentric study was conducted in consecutive patients with FI according to Rome IV criteria. To validate psychometric properties of the FI-SA questionnaire, a literature review and qualitative interviews were performed and discussed with an expert panel. A feasibility study was realized to assess acceptability and comprehension of items. The reproducibility was investigated in a validation study. RESULTS: Comprehension and acceptability were excellent in 90% of patients in the feasibility study (n = 30). Validation study (n = 100) showed a good reproducibility with an intra-class correlation coefficient of 0.91 and 0.89 for questions 1 and 2. Time to fill the questionnaire was 40.0 s. 98.0% patients were classified among subtypes of FI: 34.0% passive FI, 32.0% urge FI and 32.0% mixed FI. CONCLUSION: FI-SA is the first questionnaire to classify patients among subtypes of FI with good psychometric characteristics and the first questionnaire introducing the concept of mixed FI. FI-SA could help to determine the pertinence of this classification of FI in the management of these patients.

Virtual clinics in foot and ankle surgery: patient and clinician perceptions.

BACKGROUND: The worldwide COVID-19 pandemic has led to the popularisation of 'virtual' clinics. In orthopaedics, little is known about the use of virtual clinics within foot and ankle surgery, specifically. METHODS: A cross-sectional observation study of patients and clinicians in response to virtual clinics in foot and ankle surgery. Patients seen in a virtual clinic were contacted by telephone from two weeks after their consultation and asked to complete a 12-point questionnaire. Demographic information was also collected. Clinicians in foot and ankle completed a 10-point questionnaire. RESULTS: One hundred patient responses were collected. Patient satisfaction with virtual clinics was positive, with 65% of respondents reporting they were very happy (Likert scale rating 5). More than 90% of patients felt they received enough information, felt involved, felt the virtual clinic was helpful and knew who to contact if there was a problem. However, 79% would still prefer a face-to-face consultation, and 22% would have preferred a video consultation. Clinician responses were more cautious, with 60% stating they were neither happy nor unhappy (Likert scale rating 3). Virtual clinics may be faster for the clinician. CONCLUSIONS: Virtual clinics may be more convenient for patients, with high satisfaction levels reported, but represent significant clinical challenges for foot and ankle surgeons. Elements of virtual clinics may persist post pandemic, particularly in routine follow-up. Virtual clinics are not appropriate for new patient referrals.

Time increasing rates of infiltration and reaction in porous media at the percolation thresholds.

The infiltration of a solute in a fractal porous medium is usually anomalous, but chemical reactions of the solute and that material may increase the porosity and affect the evolution of the infiltration. We study this problem in two- and three-dimensional lattices with randomly distributed porous sites at the critical percolation thresholds and with a border in contact with a reservoir of an aggressive solute. The solute infiltrates that medium by diffusion and the reactions with the impermeable sites produce new porous sites with a probability r, which is proportional to the ratio of reaction and diffusion rates at the scale of a lattice site. Numerical simulations for r≪1 show initial subdiffusive scaling and long time Fickean scaling of the infiltrated volumes or areas, but with an intermediate regime with time increasing rates of infiltration and reaction. The anomalous exponent of the initial regime agrees with a relation previously applied to infinitely ramified fractals. We develop a scaling approach that explains the subsequent time increase of the infiltration rate, the dependence of this rate on r, and the crossover to the Fickean regime. The exponents of the scaling relations depend on the fractal dimensions of the critical percolation clusters and on the dimensions of random walks in those clusters. The time increase of the reaction rate is also justified by that reasoning. As r decreases, there is an increase in the number of time decades of the intermediate regime, which suggests that the time increasing rates are more likely to be observed is slowly reacting systems.