Freezing on a sphere.

The best understood crystal ordering transition is that of two-dimensional freezing, which proceeds by the rapid eradication of lattice defects as the temperature is lowered below a critical threshold. But crystals that assemble on closed surfaces are required by topology to have a minimum number of lattice defects, called disclinations, that act as conserved topological charges-consider the 12 pentagons on a football or the 12 pentamers on a viral capsid. Moreover, crystals assembled on curved surfaces can spontaneously develop additional lattice defects to alleviate the stress imposed by the curvature. It is therefore unclear how crystallization can proceed on a sphere, the simplest curved surface on which it is impossible to eliminate such defects. Here we show that freezing on the surface of a sphere proceeds by the formation of a single, encompassing crystalline 'continent', which forces defects into 12 isolated 'seas' with the same icosahedral symmetry as footballs and viruses. We use this broken symmetry-aligning the vertices of an icosahedron with the defect seas and unfolding the faces onto a plane-to construct a new order parameter that reveals the underlying long-range orientational order of the lattice. The effects of geometry on crystallization could be taken into account in the design of nanometre- and micrometre-scale structures in which mobile defects are sequestered into self-ordered arrays. Our results may also be relevant in understanding the properties and occurrence of natural icosahedral structures such as viruses.

Effects of Dermatan Sulfate from Marine Invertebrate Styela plicata in the Wound Healing Pathway: A Natural Resource Applied to Regenerative Therapy.

Acute and chronic dermatological injuries need rapid tissue repair due to the susceptibility to infections. To effectively promote cutaneous wound recovery, it is essential to develop safe, low-cost, and affordable regenerative tools. Therefore, we aimed to identify the biological mechanisms involved in the wound healing properties of the glycosaminoglycan dermatan sulfate (DS), obtained from ascidian Styela plicata, a marine invertebrate, which in preliminary work from our group showed no toxicity and promoted a remarkable fibroblast proliferation and migration. In this study, 2,4-DS (50 µg/mL)-treated and control groups had the relative gene expression of 84 genes participating in the healing pathway evaluated. The results showed that 57% of the genes were overexpressed during treatment, 16% were underexpressed, and 9.52% were not detected. In silico analysis of metabolic interactions exhibited overexpression of genes related to: extracellular matrix organization, hemostasis, secretion of inflammatory mediators, and regulation of insulin-like growth factor transport and uptake. Furthermore, in C57BL/6 mice subjected to experimental wounds treated with 0.25% 2,4-DS, the histological parameters demonstrated a great capacity for vascular recovery. Additionally, this study confirmed that DS is a potent inducer of wound-healing cellular pathways and a promoter of neovascularization, being a natural ally in the tissue regeneration strategy.

Random Close Packing as a Dynamical Phase Transition.

Sphere packing is an ancient problem. The densest packing is known to be a face-centered cubic (FCC) crystal, with space-filling fraction ϕ_{FCC}=π/sqrt[18]≈0.74. The densest "random packing," random close packing (RCP), is yet ill defined, although many experiments and simulations agree on a value ϕ_{RCP}≈0.64. We introduce a simple absorbing-state model, biased random organization (BRO), which exhibits a Manna class dynamical phase transition between absorbing and active states that has as its densest critical point ϕ_{c_{max}}≈0.64≈ϕ_{RCP} and, like other Manna class models, is hyperuniform at criticality. The configurations we obtain from BRO appear to be structurally identical to RCP configurations from other protocols. This leads us to conjecture that the highest-density absorbing state for an isotropic biased random organization model produces an ensemble of configurations that characterizes the state conventionally known as RCP.

Lindemann Unjamming of Emulsions.

We study the bulk and shear elastic properties of barely-compressed, "athermal" emulsions and find that the rigidity of the jammed solid fails at remarkably large critical osmotic pressures. The minuscule yield strain and similarly small Brownian particle displacement of solid emulsions close to this transition suggests that this catastrophic failure corresponds to a plastic-entropic instability: the solid becomes too soft and weak to resist the thermal agitation of the droplets that compose it and fails. We propose a modified Lindemann stability criterion to describe this transition and derive a scaling law for the critical osmotic pressure that agrees quantitatively with experimental observations.

Hyperuniform Structures Formed by Shearing Colloidal Suspensions.

In periodically sheared suspensions there is a dynamical phase transition, characterized by a critical strain amplitude γ_{c}, between an absorbing state where particle trajectories are reversible and an active state where trajectories are chaotic and diffusive. Repulsive nonhydrodynamic interactions between "colliding" particles' surfaces have been proposed as a source of this broken time reversal symmetry. A simple toy model called random organization qualitatively reproduces the dynamical features of this transition. Random organization and other absorbing state models exhibit hyperuniformity, a strong suppression of density fluctuations on long length scales quantified by a structure factor S(q→0)∼q^{α} with α>0, at criticality. Here we show experimentally that the particles in periodically sheared suspensions organize into structures with anisotropic short-range order but isotropic, long-range hyperuniform order when oscillatory shear amplitudes approach γ_{c}.

Impact of vulvovaginal atrophy on pelvic floor muscle strength in healthy continent women.

OBJECTIVES: To assess the correlation between hormonal status and pelvic floor muscle strength. METHODS: A total of 140 continent women were prospectively evaluated, and divided into four groups according to age: group 1 (n = 34) aged 30-40 years; group 2 (n = 38) aged 41-50 years; group 3 (n = 35) aged 51-60; and group 4 (n = 33) aged >60 years. The following parameters were evaluated: demographic data using clinical questionnaire; hypermobility of the bladder neck using swab test; vaginal trophism by gynecological examination; hormonal status of the vagina by cytology; and pelvic floor muscle strength using a perineometer and electromyography. RESULTS: There were no statistical differences between pelvic floor muscle strength, demographic characteristics, vaginal trophism and hypermobility of the bladder neck between groups (P > 0.05). There was a larger number of women with vaginal atrophy among those aged >60 years. Vaginal trophism assessed by pelvic examination was highly consistent with the findings of colpocytology (kappa test = 0.888). Electromyography showed that women with hypermobility had lower muscle resistance (endurance) when compared with those without hypermobility. CONCLUSIONS: Although vaginal atrophy is more intense in women aged >60 years, no difference can be found in the pelvic floor muscle strength during the physiological aging process in continent women. As a consequence, trophism is not the only factor related to pelvic floor muscle strength, and it should not preclude the selection of patients who are referred to prophylaxis.

Schooling impacts on the overactive bladder diagnosis in women.

OBJECTIVE: To evaluate the overactive bladder (OAB) diagnosis using OAB-V8 and ICIQ-OAB questionnaires in women with different schooling and cultural levels. MATERIALS AND METHODS: Three hundred and eighty six healthy women answered a clinical questionnaire filling out information about schooling, demographic and gynecological data. The OAB-V8 and ICIQ-OAB questionnaires were used to evaluate OAB diagnosis and symptoms; and the QS-F questionnaire, to determine the sexual function. All questionnaires were validated in Portuguese. RESULTS: The mean age was 37.3 years-old. Regarding to schooling level, 23.1% had concluded primary education; 65.8%, secondary school; and 11.1% had higher education. Considering the OAB-V8 (score ≥8), 51.8% of evaluated women had OAB diagnosis. There was a positive linear correlation between the OAB-V8 and ICIQ-OAB questionnaires in its sections "a" (r=0.812, p<0.001) and "b" (r=759, p<0.001). There was a positive linear correlation between age and the amount of time used to answer the OAB-V8, ICIQ-OAB and QS-F questionnaires (p<0.001). The ICIQ-OAB was the hardest to answer for all schooling levels when compared to the other questionnaires. Women who had concluded primary and secondary education significantly demanded more help to answer all questionnaires than those with higher education (p<0.05). Furthermore, women with higher education took significantly less time answering all questionnaires when compared to their less educated counterparts (primary and secondary schooling), since they were quicker to answer each individual question. CONCLUSION: Educational level and ageing had an impact on women response using different questionnaires for OAB and sexual function evaluations.

Reliability of pelvic floor muscle strength assessment in healthy continent women.

BACKGROUND: The aim of this study was to compare pelvic floor muscle (PFM) strength using transvaginal digital palpation in healthy continent women in different age groups, and to compare the inter- and intra-rater reliability of examiners performing anterior and posterior vaginal assessments. METHODS: We prospectively studied 150 healthy multiparous women. They were distributed into four different groups, according to age range: G1 (n = 37), 30-40 years-old; G2 (n = 39), 41-50 years-old; G3 (n = 39), 51-60 years-old; and G4 (n = 35), older than 60 years-old. PFM strength was evaluated using transvaginal digital palpation in the anterior and posterior areas, by 3 different examiners, and graded using a 5-point Amaro's scale. RESULTS: There was no statistical difference among the different age ranges, for each grade of PFM strength. There was good intra-rater concordance between anterior and posterior PFM assessment, being 64.7%, 63.3%, and 66.7% for examiners A, B, and C, respectively. The intra-rater concordance level was good for each examiner. However, the inter-rater reliability for two examiners varied from moderate to good. CONCLUSIONS: Age has no effect on PFM strength profiles, in multiparous continent women. There is good concordance between anterior and posterior vaginal PFM strength assessments, but only moderate to good inter-rater reliability of the measurements between two examiners.

Single-port retroperitoneal renal biopsy using standard urological instruments.

OBJECTIVE: To describe the surgical technique and initial experience with a single-port retroperitoneal renal biopsy (SPRRB). MATERIALS AND METHODS: Between January and April 2013, five children underwent SPRRB in our hospital. A single 1.5 cm incision was performed under the 12th rib at mid-axillary line, and an 11 mm trocar was inserted. A nephroscope was used to identify the kidney and dissect the perirenal fat. After lower pole exposure, a laparoscopic biopsy forceps was introduced through the nephroscope working channel to collect a renal tissue sample. RESULTS: SPRRB was successfully performed in five children. The mean operative time was 32 minutes, and mean estimated blood loss was less than 10 mL. The hospital stay of all patients was two days because they were discharged in the second postoperative day, after remaining at strict bed rest for 24 hours after the procedure. The average number of glomeruli present in the specimen was 31. CONCLUSION: SPRRB is a simple, safe and reliable alternative to open and videolaparoscopic approaches to surgical renal biopsy.

Effects of Hibiscus sabdariffa supplementation on metabolism and bladder in obese rats.

PURPOSE: Hibiscus sabdariffa (HS) extract has several health benefits and anti-obesogenic effects. The aim of the present study was to assess whether the medicinal properties attributable to HS would prevent or mitigate bladder changes induced by obesity in an experimental model. METHODS: Forty-eight male Wistar rats were submitted to one of four different dietary interventions (12 animals each): G1, standard diet and water (controls); G2, standard diet and HS tea; G3, a palatable high-fat diet and water; and G4, high-fat diet diet and HS tea. The animals were monitored for body weight, feed, and water and tea intake, according to the allocated group. After 16 weeks, the animals were euthanized, and the levels of creatinine, inflammatory cytokines, testosterone, cholesterol, triglycerides, and electrolytes were evaluated. In addition, histopathological analysis of the animals' bladder was performed. RESULTS: Groups receiving HS (G2 and G4) showed decreased levels of the pro-inflammatory cytokine interleukin-1α. HS tea was able to reduce low-density lipoprotein and triglyceride levels in the G2 group compared to other groups. Only in the G3 there was a significant increase in the body weight when it was compared the 12th and 16th weeks. Leptin was shown to be elevated in the groups that received a high-fat diet. There was a significant decrease in the muscle fibers thickness and in the total collagen count in G4 bladder when compared with G1 and G3. CONCLUSIONS: HS has an anti-inflammatory role, can reverse hyperlipidemia in rats, and reduced deleterious effects of obesity on these animals' bladder.

Acute graft thrombosis in patients who underwent renal transplant and received anticoagulant or antiplatelet agents. A systematic review and meta-analysis.

OBJECTIVES: Thrombosis is a major cause of early allograft loss in renal transplantation. Herein, we assessed the frequency of acute graft thrombosis in patients who underwent renal transplant and received anticoagulant or antiplatelet agents. METHODS: We performed a systematic review of all available case series studies of anticoagulant and/or antiplatelet prophylaxis of thrombosis in renal transplantation. The data were pooled in a proportional meta-analysis. RESULTS: Twenty-one case series were identified from 7,160 retrieved titles. A total of 3,246 patients were analyzed (1,718 treated with antiplatelet and/or anticoagulant agents and 1,528 non-treated control subjects). Allograft thrombosis occurred in 7.24% (95% CI 3.45 to 12.27%) of the patients receiving no intervention compared with 3.38% (95% CI 1.45 to 6.1%), 1.2% (95% CI 0.6 to 2.1%) and 0.47% (95% CI 0.001 to 1.79%) of the patients in the anticoagulant, aspirin, and aspirin + anticoagulant groups, respectively. The bleeding complication rate for anticoagulants was significantly higher than in the other groups. CONCLUSIONS: Our data suggests that anticoagulants, and aspirin, either alone or in association with an anticoagulant, seem to have a low frequency of acute allograft thrombosis after kidney transplantation. Higher hemorrhagic complication rates might occur when anticoagulants are used.

Fasting and 24-h urine pH in patients with urolithiasis using potassium citrate.

PURPOSE: To evaluate the correlation between the pH readings in 24-h urine and the random fasting specimen in patients with urolithiasis using 2 methods. METHODS: A total of 114 patients with urinary lithiasis using potassium citrate were prospectively analyzed. All patients collected 24-h urine and an additional sample, after nocturnal fasting, collected on the day they brought the 24-h sample at the lab. Two different methods (test strip and digital meter) were used to determine pH values. RESULTS: The pH analysis using strips in the 24-h urine presented a mean value similar to the one obtained in the fasting sample (6.07 ± 0.74 vs. 6.02 ± 0.82, respectively; P > 0.05). The same behavior was seen considering the readings with a digital pH meter (5.8 ± 0.78 vs. 5.75 ± 0.83; P > 0.05). However, readings conducted in the same specimen with pH meter and test strip were dissonant (P < 0.05), suggesting that the colorimetric method is not reliable in the assessment of urinary pH in this population. CONCLUSION: pH assessment in a random urinary specimen proved as efficient as the 24-h urine standard method to monitor patients with kidney stones in the use of potassium citrate. Classical test strip analysis is not sensitive enough to evaluate the urine pH in this population and digital pH meter reading is preferred.

Interstitial fluid velocity is decreased around cortical bone vascular pores and depends on osteocyte position in a rat model of disuse osteoporosis.

Muscle paralysis induced with botulinum toxin (Botox) injection increases vascular porosity and reduces osteocyte lacunar density in the tibial cortical bone of skeletally mature rats. These morphological changes potentially affect interstitial fluid flow in the lacunar-canalicular porosity, which is thought to play a role in osteocyte mechanotransduction. The aim of this study was to investigate the effects of disuse-induced morphological changes on interstitial fluid velocity around osteocytes in the bone cortex. Micro-CT images from a previous study that quantified the effects of Botox-induced muscle paralysis on bone microarchitecture in skeletally mature rats were used to create high-resolution, animal-specific finite element models that included the vascular pores and osteocyte lacunae within the tibial metaphysis of Botox-injected (BTX, n = 8) and saline-injected control (CTRL, n = 8) groups. To quantify fluid flow, lacunar and canalicular porosities were modeled as fluid-saturated poroelastic materials, and boundary conditions were applied to simulate physiological loading. This modeling approach allowed a detailed quantification of the fluid flow velocities around osteocytes in a relatively large volume of bone tissue. The analysis demonstrated that interstitial fluid velocity at the vascular pore surfaces was significantly lower in BTX compared to CTRL because of the decreased vascular canal separation. No significant differences in average fluid velocity were observed at the osteocyte lacunae and no correlation was found between the fluid velocity and the lacunar density, which was significantly lower in BTX. Instead, the lacunar fluid velocity was dependent on the osteocyte's specific position in the bone cortex and its proximity to a vascular pore.

Pelvic floor muscle strength is correlated with sexual function.

PURPOSE: Sexual performance is related to proprioception and pelvic floor muscle strength (PFMS). The aim of this study was to correlate sexual activity and orgasm with PFMS. MATERIALS AND METHODS: A total of 140 healthy continent female were prospectively distributed into 4 groups according to age: Group 1 (G1), 30-40; Group 2 (G2), 41-50; Group 3 (G3), 51-60; Group 4 (G4), over 60 years old. Evaluated parameters were: frequency of sexual activity and orgasm achievement; body mass index (BMI) and objective evaluation of PFMS using perineometer and surface electromyography. RESULTS: BMI was higher in G4 compared to G1 (p=0.042). Women who reported sexual activity was significantly higher in G1 compared to G3 and G4 (94.1% vs. 66.7% and 37.5%, respectively; p=0.001). Orgasm was more frequently in G1 compared to G3 and G4 (91.2% vs. 63.9% and 28.1%, respectively; p=0.001), demonstrating that sexual activity and orgasm decrease after age 51. The duration of PFM contraction was significantly higher in women who had sexual intercourse (p=0.033) and orgasm (p=0.018). CONCLUSIONS: Although the frequency of sexual intercourse and orgasm may decrease with aging, a relationship between sexual activity and PFMS remains apparent, once both sexually active women and those who have orgasms showed better PFM endurance than non-sexually active ones.

Impact of Time-Zero Biopsy on the Outcome of Transplanted Kidneys.

BACKGROUND: A low supply of donated organs led to the expansion of criteria for kidney transplantation (KT), and the impact on late glomerular function rates (eGFR) is still uncertain. This study aimed to correlate the histologic findings at time-zero biopsy (TzB) with the final eGFR, to identify criteria that could help achieve a more thorough preimplantation evaluation of the organ. METHODS: Records from 395 adult deceased KTs were reviewed. TzBs were analyzed considering histologic criteria by compartment (vascular, interstitial, tubular, and inflammatory) and correlated with the eGFR after 1 year. RESULTS: Among donors, 56.9% were men (mean age 39 years), with the main causes of death being brain trauma (44.2%) and stroke (46.0%). Histologic analysis of TzB revealed 6.0% of glomerulosclerosis; 18.8% presenting vascular alterations; interstitial fibrosis in 54.6%; tubular changes in 76.9%, and nonspecific inflammatory infiltrate in 2.3%. Linear regression analysis showed that the main histologic findings that had impact in the eGFR were interstitial fibrosis (P = .000), followed by tubular alterations (P = .036) and glomerulosclerosis (P = .008). CONCLUSIONS: Histologic variables like interstitial fibrosis and tubular alterations show the most significant negative correlation with final eGFR. The effect of glomerulosclerosis may not be as important as formerly suggested in the literature.

Challenges and Future Directions of Big Data and Artificial Intelligence in Education.

We discuss the new challenges and directions facing the use of big data and artificial intelligence (AI) in education research, policy-making, and industry. In recent years, applications of big data and AI in education have made significant headways. This highlights a novel trend in leading-edge educational research. The convenience and embeddedness of data collection within educational technologies, paired with computational techniques have made the analyses of big data a reality. We are moving beyond proof-of-concept demonstrations and applications of techniques, and are beginning to see substantial adoption in many areas of education. The key research trends in the domains of big data and AI are associated with assessment, individualized learning, and precision education. Model-driven data analytics approaches will grow quickly to guide the development, interpretation, and validation of the algorithms. However, conclusions from educational analytics should, of course, be applied with caution. At the education policy level, the government should be devoted to supporting lifelong learning, offering teacher education programs, and protecting personal data. With regard to the education industry, reciprocal and mutually beneficial relationships should be developed in order to enhance academia-industry collaboration. Furthermore, it is important to make sure that technologies are guided by relevant theoretical frameworks and are empirically tested. Lastly, in this paper we advocate an in-depth dialog between supporters of "cold" technology and "warm" humanity so that it can lead to greater understanding among teachers and students about how technology, and specifically, the big data explosion and AI revolution can bring new opportunities (and challenges) that can be best leveraged for pedagogical practices and learning.

Use of colon cancer testing in rural Colorado primary care practices.

BACKGROUND: People living in rural areas may be less likely to be up to date (UTD) with screening guidelines for colorectal cancer (CRC). OBJECTIVES: To determine (1) rates of being UTD with screening or ever having had a test for CRC and (2) correlates for testing among patients living in a rural area who visit a provider. DESIGN: Cross-sectional survey. PARTICIPANTS: Five hundred seventy patients aged 50 years and older who visited their health-care provider in High Plains Research Network (HPRN) practices. MEASUREMENTS: (1) Ever having had a CRC screening test, (2) being UTD with CRC screening, and (3) intention to get tested. RESULTS: The survey completion rate was 65%; 71% of patients had ever had any CRC screening test, while 52% of patients were UTD. Correlates of intending to get tested included having a family history of CRC, having a doctor recommend a test, knowing somebody who got tested, and believing that testing for CRC gives one a feeling of being in control of their health. Of those who had never had a CRC screening test, 12% planned on getting tested in the future, while 55% of those who were already up to date intended to be tested again (p < 0.001). CONCLUSIONS: Prevalence of being UTD with CRC testing in the HPRN was on par with statewide CRC testing rates, but over three quarters of patients who had not yet been screened had no intention of getting tested for CRC, despite having a medical home.

Effects of tadalafil to prevent injury on corpus cavernosum after vascular or nervous peri-prostatic bundle injury. Experimental model in rats.

PURPOSE: To evaluate the effects of tadalafil (TD) in preventing histological alterations of the corpus cavernosum caused by isolated lesions of cavernous nerve (ILCN) and artery (ILCA) in rats. METHODS: Fifty male Wistar rats were randomly assigned in five groups: G1: control; G2: bilateral ILCN; G3: bilateral ILCA; G4: ILCN+TD; G5: ILCA+TD. The cavernous bodies were submitted to histomorphometry, immunohistochemistry and biochemical analysis. RESULTS: Nerve density was significantly higher in G2 and G4 compared to control (22.62±2.84 and 19.53±3.47 vs. 15.72±1.82; respectively, p<0.05). Smooth muscle density was significantly lower in G2 and G3 in comparison to G1 (12.87±1.90 and 18.93±1.51 vs. 21.78±1.81, respectively; p<0.05). A significant decrease in the sinusoidal lumen area was observed in G2 compared to controls (5.01±1.62 vs. 9.88±3.66, respectively; p<0.05) and the blood vessel density was increased in G2 and G3 (29.32±4.13 e 20.80±2.47 vs. 10.13±2.71, p<0.05). Collagen density was higher in G3 compared to G1 (93.76±15.81 vs. 64.59±19.25; p<0.05). CONCLUSIONS: Histomorphometric alterations caused by ILCN were more intense than those produced by vascular injury, but the collagen analyses showed more fibrosis in animals with ILCA. TD was effective in preventing the majority of the alterations induced by the periprostatic bundle injury.

Self-faceting of emulsion droplets as a route to solid icosahedra and other polyhedra.

HYPOTHESIS: Temperature-controlled self-faceting of liquid droplets has been recently discovered in surfactant-stabilized alkane-in-water emulsions. We hypothesize that similar self-faceting may occur in emulsion droplets of UV-polymerizable linear hydrocarbons. We further hypothesize that the faceted droplet shapes can be fixed by UV-initiated polymerization, thus providing a new route towards the production of solid polyhedra. EXPERIMENTS: Temperature-induced shape variations were studied by optical microscopy in micron-size emulsion droplets of UV-polymerizable alkyl acrylate. When polymerized, the resultant solid particles' 3D shape and internal structure were determined by combined scanning electron microscopy (SEM) and focused ion beam (FIB) slicing. The SEM and FIB nanoscale resolution provided a far greater detail imaging than that achievable for the liquid droplets, which could only be studied by optical microscopy, severely limiting their 3D shape determination. FINDINGS: We demonstrate the formation of solid icosahedra, polyhedral platelets, and rods of hitherto-unreported sizes, well below the 3D-printing resolution (∼20µm). The presence of icosahedral shapes and the absence of any resolvable internal structure at sub-µm length scales, are in line with the surface-freezing-driven mechanism proposed for the faceting phenomenon. Further development of the method presented here may allow large-quantity production of shaped micron- to nano- sized colloidal building blocks for 3D metamaterials and other applications.