The Spectrum of ACS: Towards a More Personalized Approach

On 24 September 1955, Wall Street was in a panic and shares plummeted [...].

Feasibility of transcatheter closure for absent aortic rim in patients with atrial septal defect

OBJECTIVES

This study aimed to assess the feasibility of transcatheter atrial septal defect (ASD) closure in patients with absent aortic rim.

BACKGROUND

The indication of transcatheter closure for ASD with absent aortic rim is controversial.

METHODS

We enrolled 547 patients with ASD who were scheduled for transcatheter closure. Morphologies of aortic rim were evaluated using transesophageal echocardiography (TEE).

RESULTS

Aortic rim of <5 mm was observed in 396 (72%) patients; 128 (23%) had absent aortic rim of 0 mm, and 268 (49%) had deficient aortic rim of >0 to <5 mm. Patients with absent aortic rim frequently had aortic rim absence at an angle of 0° on TEE and septal malalignment. Of the 128 patients with absent aortic rim, 126 (98%) successfully underwent transcatheter closure, while 2 (2%) failed transcatheter closure due to a large defect with severe septal malalignment. The success rate of transcatheter closure was similar between patients with absent aortic rim and those with deficient aortic rim (98% vs. 99%, p = .45). After the procedure, no patients had erosion or device embolization during a median follow-up of 24 months.

CONCLUSIONS

Transcatheter closure was successfully performed without adverse events in patients with absent aortic rim, as well as in those with deficient aortic rim. Our findings can be valuable to determine the indication of transcatheter closure in patients with ASD.

Ionic Cross-Linking as a Strategy to Modulate the Properties of Oral Mucoadhesive Microparticles Based on Polysaccharide Blends

Polymer blends of gellan gum (GG)/retrograded starch(RS) and GG/pectin (P) were cross-linked with calcium, aluminum, or both to prepare mucoadhesive microparticles as oral carriers of drugs or nano systems. Cross-linking with different cations promoted different effects on each blend, which can potentially be explored as novel strategies for modulating physical-chemical and mucoadhesive properties of microparticles. Particles exhibited spherical shapes, diameters from 888 to 1764 µm, and span index values lower than 0.5. Blends of GG:P cross-linked with aluminum resulted in smaller particles than those obtained by calcium cross-linking. GG:RS particles exhibited larger sizes, but cross-linking this blend with calcium promoted diameter reduction. The uptake rates of acid medium were lower than phosphate buffer (pH 6.8), especially GG:RS based particles cross-linked with calcium. On the other hand, particles based on GG:P cross-linked with calcium absorbed the highest volume of acid medium. The percentage of systems erosion was higher in acid medium, but apparently occurred in the outermost layer of the particle. In pH 6.8, erosion was lower, but caused expressive swelling of the matrixes. Calcium cross-linking of GG:RS promoted a significantly reduction on enzymatic degradation at both pH 1.2 and 6.8, which is a promising feature that can provide drug protection against premature degradation in the stomach. In contrast, GG:P microparticles cross-linked with calcium suffered high degradation at both pH values, an advantageous feature for quickly releasing drugs at different sites of the gastrointestinal tract. The high mucoadhesive ability of the microparticles was evidenced at both pH values, and the Freundlich parameters indicated stronger particle-mucin interactions at pH 6.8.

Assessment of oral health status and treatment needs of drug abusers in Bhubaneswar city: A cross-sectional study

Introduction:

Oral health of drug abusers has received less attention. Drug users may also have special needs in relation to receiving dental care. Evaluation of the oral health status of drug abusers is important as in India, where the disease burden is enormous, and availability of curative treatment is quite inadequate, preventive approach shall prove to be better than curative treatment.

Aim:

To determine the oral health status and treatment needs of drug abusers residing in rehabilitation centers in Bhubaneswar.

Materials and Methods:

A cross-sectional study was conducted in the drug de-addiction cum rehabilitation centers in Bhubaneswar city, Odisha. A self-administered questionnaire was used to record oral health practices of the inmates and the type of drugs used by them in the past. Oral health was recorded using modified WHO 2013 pro forma. Mann–Whitney U-test and Kruskal–Wallis test were applied to find any significant differences between different variables in groups.

Results:

All the participants were male and alcohol was the most commonly used drug, followed by tobacco and ganja. The horizontal brushing technique was the most widely used technique. Mean decayed, missing, and filled teeth (DMFT) score was recorded to be 1.48. Leukoplakia, acute necrotizing ulcerative gingivitis, candidiasis, and ulceration were among the few oral lesions found in the inmates. Around 67.66% of inmates exhibited erosion of the enamel surface, while 6.59% had signs of enamel fracture. Statistically, significant difference was found for the types of drugs used and DMFT score and type of drug used and dental erosion.

Conclusion:

Oral health status of drug users is poor and needs immediate attention. Oral health education needs to be imparted among them. The government needs to enforce the establishment of dental clinics in these centers so that the oral health of these people can be taken care of.

Application of Innovative Ropes from Textile Waste as an Anti-Erosion Measure

Using materials from recycling is a key part of decreasing present-day waste. It is optimal for recycled material to be used in environmental protection. This paper presents the application of geotextile ropes in erosion protection of a slope of a gravel pit. To protect the slope, thick ropes with a diameter of 120 mm made from wool and a mixture of recycled natural and synthetic fibers were used. After 47 months from installation, soil and rope specimens were taken from the slope parts with inclinations 1:1 and 1:1.8, and their physical and mechanical properties were determined. Direct shear tests were applied to determine the soil shear strength parameters in state at sampling and at I_c = 0 (unconsolidated and consolidated). Based on the obtained soil shear strength parameters, the loads on the ropes were determined, taking into account also unfavorable hydraulic conditions and compared to rope strength. It was shown that even after 47 months from installation, rope tension strength was higher as tension forces were induced in the ropes in every case. At present, whole slopes in protected sections are stabilized, without rills and gullies.

Intraspecific variation in landform engineering across a restored salt marsh shoreline

Ecosystem engineers that modify landforms can be valuable tools for restoring habitat, but their use has frequently resulted in unanticipated outcomes. Departures from expectations might arise because applications discount the possibility that geomorphic processes are influenced by heritable phenotypic variation. We conducted a field-scale common garden experiment to assess whether shoreline erosion reflects intraspecific variation in the landform engineer Spartina alterniflora. Replicated plots on a shoreline denuded by the Deepwater Horizon oil spill were revegetated using plants from four genetically distinct sources: the local population, a nonlocal population, and two nursery stocks. We assessed variation in biomass, tissue nutrients, and functional traits alongside soil shear strength, surface elevation, and shoreline erosion rates over 2 years. We found that productivity, traits, nutrient content, and erosion rates varied according to plant provenance. Erosion reflected traits like root architecture more so than coarser metrics of growth. Erosion was significantly higher in plots with nonlocal plants that exhibited lower productivity, likely due to nitrogen limitation. Our results indicate that restoration practices should account for intraspecific variation in landform engineers and that in situ trials should be performed at sites slated for restoration to evaluate donor source suitability, particularly if introductions might modify local populations.

Histopathologic Manifestations of Crohn Disease in Duodenal Endoscopy Biopsy: The Value of Different Patterns of Involvement of Brunner Glands

Crohn disease (CD) not uncommonly involves the upper gastrointestinal tract, usually gastric antrum and proximal duodenum. The most consistent histopathologic manifestations of CD in duodenal biopsies are mucosal erosion, focal active inflammation, and granulomas. Since CD is a transmural inflammation and since duodenal biopsy may include submucosal Brunner glands, we aimed to find if CD has any specific histopathologic manifestations in Brunner gland lobules and their ducts compared to other duodenal inflammatory lesions. We carried out a retrospective review study over 6 years retrieving duodenal biopsy specimens in CD patients. We compared duodenal specimens involved by CD with other inflammatory lesions, for example, ulcerative colitis (UC), Helicobacter pylori-associated gastritis, non-Helicobacter gastritis, Celiac sprue, infections, and drugs. We found focal active duodenitis and erosion in CD cases and non-CD cases. Granulomas were found in CD cases. Five cases of CD showed inflammatory and degenerative changes of Brunner glands. Focal patchy active inflammation of only portion of submucosal Brunner gland lobule, mucosal Brunner glands, and their ducts was solely found in CD cases. This focally enhanced inflammation of Brunner glands was not found in other lesions. Whether this phenomenon of focal active "lobulitis" and "ductitis" is a specific sign of duodenal CD compared to UC and other inflammatory lesions warrants verification. We encourage endoscopists to include submucosal Brunner lobules in their duodenal biopsy samples and pathologists to look for these patterns of involvement particularly in patients suspected of CD.

In vitro efficacy of commercial and experimental proteolytic enzyme-based whitening dentifrices on enamel whitening and superficial roughness

OBJECTIVE

To evaluate the whiteness index (W_ID ) and surface roughness (Ra) of bovine enamel after simulated tooth brushing with different commercial and experimental whitening dentifrices.

MATERIALS AND METHODS

Cylindrical enamel bovine specimens were acid etched, stained, and divided in nine groups (n = 8): Colgate® Optic White®, Crest® Baking Soda and Peroxide, Arm and Hammer® Advanced White™ Extreme Whitening, Rembrandt® Deeply White® + Peroxide, Close up® White Attraction Natural Glow, Hinode Prowhite, and experimental dentifrice containing papain (PP), bromelain (PB), or papain and bromelain (PPB). Ra and W_ID were obtained initially and after 600, 1200, and 3,600 cycles of simulated tooth brushing. Data were analyzed using two-way analysis of variance test (α = 0.05).

RESULTS

Ra was significantly influenced by both dentifrice (p = 0.043) and period of tooth-brushing simulation (p < 0.001). Except for PP and PPB, all groups showed a statistically significant increase in Ra after simulated tooth brushing. After staining and brushing, none of the materials tested increased the initial W_ID .

CONCLUSIONS

The effect of commercial whitening dentifrices may be related to their high abrasiveness. Experimental formulations tested provided a similar effect without undesired wear of enamel. Whitening dentifrices only act through an abrasive effect rather than bleaching the tooth structures. When used, special care must be taken for avoid undesired wear of enamel. Experimental dentifrices provided similar removal of extrinsic stains without undesired abrasiveness; however, this effect may be due to the use of less aggressive abrasives in their formulations.

The Development of Equipment to Measure Mesh Erosion of Soft Tissue

Mesh erosion is a phenomenon whereby soft tissue becomes damaged as a result of contact with implants made from surgical mesh, a fabric-like material consisting of fibers of polypropylene or other polymers. This paper describes the design and construction of a testing machine to generate mesh erosion in vitro. A sample of mesh in the form of a 10 mm wide tape is pressed against soft tissue (porcine muscle) with a given force, and a given reciprocating movement is applied between the mesh and the tissue. To demonstrate the capabilities of the equipment, we measured erosion using the same mesh and tissue type, varying the applied force and the reciprocating stroke length, including zero strokes (i.e., static loading). For comparison, we also tested four other samples of polypropylene with different edge characteristics. Analysis of the results suggests the existence of three different erosion mechanisms: cutting, wear and creep. It is concluded that the equipment provides a useful and realistic simulation of mesh erosion, a phenomenon that is of great clinical significance and merits further study.

Effects of mangrove cover on coastal erosion during a hurricane in Texas, USA

We tested the hypothesis that mangroves provide better coastal protection than salt marsh vegetation using 10 1,008-m² plots in which we manipulated mangrove cover from 0 to 100%. Hurricane Harvey passed over the plots in 2017. Data from erosion stakes indicated up to 26 cm of vertical and 970 cm of horizontal erosion over 70 months in the plot with 0% mangrove cover, but relatively little erosion in other plots. The hurricane did not increase erosion, and erosion decreased after the hurricane passed. Data from drone images indicated 196 m² of erosion in the 0% mangrove plot, relatively little erosion in other plots, and little ongoing erosion after the hurricane. Transects through the plots indicated that the levee (near the front of the plot) and the bank (the front edge of the plot) retreated up to 9 m as a continuous function of decreasing mangrove cover. Soil strength was greater in areas vegetated with mangroves than in areas vegetated by marsh plants, or nonvegetated areas, and increased as a function of plot-level mangrove cover. Mangroves prevented erosion better than marsh plants did, but this service was nonlinear, with low mangrove cover providing most of the benefits.

Pulsatile Flow-Induced Fatigue-Resistant Photopolymerizable Hydrogels for the Treatment of Intracranial Aneurysms

An alternative intracranial aneurysm embolic agent is emerging in the form of hydrogels due to their ability to be injected in liquid phase and solidify in situ. Hydrogels have the ability to fill an aneurysm sac more completely compared to solid implants such as those used in coil embolization. Recently, the feasibility to implement photopolymerizable poly(ethylene glycol) dimethacrylate (PEGDMA) hydrogels in vitro has been demonstrated for aneurysm application. Nonetheless, the physical and mechanical properties of such hydrogels require further characterization to evaluate their long-term integrity and stability to avoid implant compaction and aneurysm recurrence over time. To that end, molecular weight and polymer content of the hydrogels were tuned to match the elastic modulus and compliance of aneurysmal tissue while minimizing the swelling volume and pressure. The hydrogel precursor was injected and photopolymerized in an in vitro aneurysm model, designed by casting polydimethylsiloxane (PDMS) around 3D printed water-soluble sacrificial molds. The hydrogels were then exposed to a fatigue test under physiological pulsatile flow, inducing a combination of circumferential and shear stresses. The hydrogels withstood 5.5 million cycles and no significant weight loss of the implant was observed nor did the polymerized hydrogel protrude or migrate into the parent artery. Slight surface erosion defects of 2–10 μm in depth were observed after loading compared to 2 μm maximum for non-loaded hydrogels. These results show that our fine-tuned photopolymerized hydrogel is expected to withstand the physiological conditions of an in vivo implant study.

Identification, localization and differentiation of erosions and physiological bone channels by ultrasound in rheumatoid arthritis patients

OBJECTIVES

Ultrasound (US) can detect cortical bone lesions in RA. However, not all cortical bone lesions are erosions. Herein, we aimed to define whether US can differentiate between physiological bone channels and pathological erosions in RA and to provide topographic description of their differential localization.

METHODS

RA patients and healthy controls (HC) received US examination of the metacarpophalangeal (MCPJ) and proximal inter-phalangeal (PIPJ) joints adjudicating cortical bone lesions as physiological bone channels or pathological erosions. In a subset of RA patients and HC, high-resolution peripheral quantitative computed tomography (HR-pQCT) of the hand was performed to validate the classification of lesions.

RESULTS

A total of 40 RA patients and 43 HC were enrolled and totally 771 MCPJ and 638 PIPJ were examined by US, and 94 and 51, respectively, by HR-pQCT. US-defined cortical bone lesions clustered in the lateral part of the MCP (50%) and the dorsal part of the PIPJ (66.7%) in RA. US-defined physiological bone channels clustered in the palmar parts of the MCPJ and PIPJ in both RA (78.8% and 100%, respectively) and HC (51.8% and 80%, respectively). HR-pQCT data confirmed US data with respect to adjudication of physiological bone channels and pathological erosions. Erosions were significantly (all P <0.000001) larger than physiological channels and preferentially localized at radial and ulnar sites, while physiological channels were clustered at palmar sites. Specificity of US was excellent for erosions in RA and for physiological bone channels in HC and RA.

CONCLUSION

US allows differentiation between physiological channels and bone erosions in RA.

Erosive Potential of Bottled Salad Dressings

PURPOSE

A previous clinical study showed that the prevalence of erosive toothwear in vegetarians is statistically significantly higher than in nonvegetarians, due to the consumption of vinegar and other acidic foodstuffs. To adequately inform patients, this study investigated the erosive potential of bottled salad dressings available in Switzerland and compared it with that of orange juice. Materials and Methods: One hundred enamel samples of bovine teeth were divided into ten groups. Samples were placed in 1 of 9 bottled salad dressings or orange juice (Granini) for 2 min. Afterwards, they were rinsed with Zürich tap water for 30 s, followed by abrasion with a toothbrush for 20 brush strokes and a toothpaste-saliva mixture. Erosive/abrasive enamel wear was determined with contact profilometry after 40 cycles. Results: The enamel wear (median/IQR) caused by Tradition Sauce Balsamique (9.5 µm/5.3 µm), M-Classic Dressing Italiano (10.9 µm/12.3 µm), Betty Bossi Balsamico Dressing (9.4 µm/4.5 µm) and Thomy Balsamico Vinaigrette Dressing (14.2 µm/6.5 µm) was statistically significantly higher than that caused by orange juice (2.4 µm/0.8 µm). Enamel wear caused by M-Classic Dressing French Joghurt (0.2 µm/0.2 µm) and Coop Qualité & Prix French Dressing (1.2 µm/1.0 µm) was statistically significantly lower compared to that of orange juice. Conclusions: The pure balsamico vinegar-based dressings (Italian type) showed a statistically significantly higher erosive potential than orange juice, whereas dressings containing calcium-rich products (enriched with milk and/or cream) (French-type) caused lower enamel wear than orange juice. The study shows that some bottled dressings have erosive potential even higher than orange juice and patients should be informed accordingly.

Strive to Reduce Slurry Erosion and Cavitation in Pumps Through Flow Modifications, Design Optimization and Some Other Techniques: Long Term Impact on Process Industry

Centrifugal pumps are being widely used in various industries for moving fluids that carry solids through pipelines where the need of head and flow rate is not high. Slurry erosion and cavitation are an extremely complex and not yet fully understood phenomenon that occur in centrifugal pumps; however, these undesirable phenomena can be reduced to a certain extent. Appropriate design and development of experiments is required to reasonably predict slurry erosion and cavitation. However, CFD methodology complements analytical solutions and experiments whenever testing of equipment has limitations. The current paper highlights the various slurry erosion and cavitation reduction techniques utilized by different researchers. Economic analysis conducted for a case study relevant to centrifugal pump (CP) usage in Pakistan shows that an 8% enhancement in pump efficiency can reduce the life cycle cost to about 17.6%, which could save up to USD 4281 for a single pump annually in Pakistan.

Can N2 O emissions offset the benefits from soil organic carbon storage?

To respect the Paris agreement targeting a limitation of global warming below 2°C by 2100, and possibly below 1.5°C, drastic reductions of greenhouse gas emissions are mandatory but not sufficient. Large-scale deployment of other climate mitigation strategies is also necessary. Among these, increasing soil organic carbon (SOC) stocks is an important lever because carbon in soils can be stored for long periods and land management options to achieve this already exist and have been widely tested. However, agricultural soils are also an important source of nitrous oxide (N₂ O), a powerful greenhouse gas, and increasing SOC may influence N₂ O emissions, likely causing an increase in many cases, thus tending to offset the climate change benefit from increased SOC storage. Here we review the main agricultural management options for increasing SOC stocks. We evaluate the amount of SOC that can be stored as well as resulting changes in N₂ O emissions to better estimate the climate benefits of these management options. Based on quantitative data obtained from published meta-analyses and from our current level of understanding, we conclude that the climate mitigation induced by increased SOC storage is generally overestimated if associated N₂ O emissions are not considered but, with the exception of reduced tillage, is never fully offset. Some options (e.g. biochar or non-pyrogenic C amendment application) may even decrease N₂ O emissions.

Cold Gas Spraying of Nickel-Titanium Coatings for Protection Against Cavitation

Cavitation erosion is a sever wear mechanism that takes place in hydrodynamic systems. Examples are turbine vanes of hydropower plants or components of valves and pumps in hydraulic systems. Nickel-titanium shape memory alloys (NiTi) are attractive materials for cavitation-resistant coatings because of their pronounced intrinsic damping mitigating cavitation-induced erosion. In this work, NiTi coatings were produced by cold gas spraying. The phase transformation behaviors of the powder feedstock and the as-sprayed coatings were investigated. Regarding the obtained transformation temperatures, the measured substrate temperatures during spraying rule out that either the shape memory effect or the pseudoelasticity of NiTi could affect the deposition efficiency under the applied conditions of cold gas spraying. Another potential effect is stress-induced amorphization which could occur at the particle-substrate interfaces and impair particle bonding by stress relaxation. Moreover, also oxide formation can be significant. Thus, the presence of amorphous phases and oxides in the near-surface zone of particles bounced off after impact was investigated. Oxidation could be confirmed, but no indication of amorphous phase was found. Besides, also the evolution of local microstrains implies that the substrate temperatures affect the deposition efficiency. These temperatures were significantly influenced by the spray gun travel speed.

Tooth Wear: Best Evidence Consensus Statement

PURPOSE

The purpose of this Best Evidence Consensus Statement was to evaluate the impact of wear on teeth.

MATERIALS AND METHODS

A search updated last on the 07th October 2020 using the terms tooth wear, dental erosion, dental abrasion or dental attrition yielded 11,694 results. Limiting the search to clinical trials, cross-sectional investigations, randomized controlled trials, reviews, systematic reviews and meta-analysis yielded 1,769 results. Mechanistic in vitro studies were also added to the list of abstracts supplying additional information of the impact of wear on teeth. All abstracts were reviewed by two authors. Those relating to the focus question formed the evidence base which was used to formulate the response.

RESULTS

From the search results, 212 articles were related to the research question and 60 were included in this paper. Although tooth wear prevalence is over 30% of the population in early adulthood and increases as individual's age, the impact on the dentition is poorly investigated in longitudinal clinical studies. Wear on teeth can result in alterations in shape and potentially dentine hypersensitivity depending on the etiology. However, the process is slow and pulpal death is rare. The impact that tooth wear has on the patient depends on patient characteristics to a greater extent than the severity of wear.

CONCLUSIONS

Tooth wear is a common condition and part of the ageing process. Erosive tooth wear is a term which acknowledges that acids are normally linked to progression, but mechanical actions of attrition and abrasion will cause visible damage. The changes to the shape of teeth on the macro and micro levels are used to investigate the progression, prevention, etiology, and management. The biological impact of wear on teeth is relatively innocuous and management is often a patient driven process. This article is protected by copyright. All rights reserved.

Erosion of Cardiovascular Implantable Device: Conservative Therapy or Extraction?

The standard of care for device infection is normally a complete removal of the implantable system, including lead extraction in local or systemic infection cases. Despite the importance of lead extraction techniques, these techniques are complex and have some major risks. Success rates were high, but they are less favorable in patients with several comorbidities. An 80-year-old male presented for device erosion. The patient is known to have several cardiac comorbidities: a transcatheter aortic valve replacement (TAVR), mitral clips for severe aortic stenosis, mitral regurgitation, dual-chamber implantable cardioverter defibrillators (ICD) for secondary prevention. Several weeks ago, he noted tenderness and redness at the site of his device pocket, and his physician, after checking his wound, suggested a possible skin irritation with no systemic infection and started antibiotics treatment. Two weeks later, he noted thinning of the skin around the device with a hematoma and ecchymosis, and slight skin erosion. Strategies for assessment of the wound and pocket cleaning were taken. The strategy was to remove the left-sided device and keep the leads since the patient lately has no elevated inflammatory labs, negative cultures, no fever, nor signs of vegetation on transesophageal echocardiography (TEE) and refused any additional examination as positron emission tomography (PET) scan, and reimplant a new system on the contralateral side. The procedure was divided into two sequences: extracting the device and after one-week implantation of a right-sided new system. In this case, chronic antibiotics were discussable to decrease the recurrence rate, but they did increase the severity of the patient's thrombocytopenia. Despite extraction being the gold standard of treatment in most cases of devices with local and systemic infection, there are some frail patients with several comorbidities where extraction is unbearable due to its major risks and complex procedure. In these specific cases with local infection and device erosion with no signs of any systemic infection, conservative therapy could be a viable option.

Demineralization Inhibition by High-Speed Scanning of 9.3 µm CO2 Single Laser Pulses Over Enamel

BACKGROUND AND OBJECTIVE

In vitro studies were conducted to evaluate the use of an automated system for high-speed scanning of single 9.3 µm CO₂ laser pulses in the inhibition of caries-like lesion formation in the enamel of extracted human molars. The effect of the laser in generating an acid-resistant layer and the effect of the layer on inhibiting surface mineral loss during pH cycling was explored.

STUDY DESIGN/MATERIALS AND METHODS

Laser irradiation was performed with fluences of 0.6, 0.8, and 1.0 J/cm² for single pulses of 1 mm diameter (1/e² ), with pulse durations of 17, 22, and 27 microseconds, respectively. The laser was scanned at a 750 Hz pulse repetition rate in an automated pattern covering an area of 7 mm² in 0.3 sec. Six treatment groups were investigated: three groups for each fluence for laser-only and three for laser irradiation with additional fluoride from a toothpaste slurry (sodium fluoride at 1100 ppm). Each group used non-irradiated areas, which included untreated controls for the laser-only groups and a fluoride-only treatment for the groups with additional fluoride. pH cycling was performed on both groups, followed by microhardness testing to determine the relative mineral loss (∆Z) from a caries-like formation and surface mineral loss (∆S).

RESULTS

Laser irradiation with the 9.3 µm CO₂ laser generated an acid-resistant layer of about 15 µm in depth. For the laser-irradiated samples with additional fluoride application, the relative mineral loss (∆Z) was 113 ± 63 vol%-µm, while for those with only fluoride application ∆Z was 572 ± 172 vol%-µm. At the highest fluence (1.0 J/cm² ) used, an 80.2% inhibition of caries-like lesion was measured by ∆Z. Using only laser irradiation at the highest fluence resulted in an inhibition of caries-like lesion of 79.5% for the irradiated samples (∆Z = 374 ± 149 vol%-µm) relative to the control (∆Z = 1826 ± 325 vol%-µm). Surface microhardness tests resulted in an inhibition of surface softening, as measured by the Knoop Hardness Value (KHN) (108 ± 33 KHN for laser irradiated with additional fluoride, for non-irradiated controls with fluoride only 52 ± 16 KHN). Inhibition of surface loss was observed for all laser fluences, but the maximum surface loss for the untreated control group was only 2.2 ± 0.49 µm.

CONCLUSIONS

The results demonstrate a significant benefit of the 9.3 µm CO₂ laser at fluences of 0.6, 0.8, and 1.0 J/cm² in caries-like lesion inhibition as measured by the relative mineral loss in depth and surface mineral loss, without significant damage to the enamel. Additionally, inhibition of surface softening and surface loss during pH cycling was observed. The surface loss was small compared with the overall lesion depth and thickness of the generated acid-resistant layer. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

In vivo osseointegration and erosion of nacre screws in an animal model

The use of resorbable devices for osteosynthesis has become a subject of interest. Nacre has been proposed as a resorbable and osteoconductive material favoring bone apposition without triggering an inflammatory reaction. We compared the in vivo osseointegration and erosion of nacre screws in an animal model with titanium screws. Implantation of similar nacre and titanium screws was performed in the femoral condyles of adult rats. Animals (n = 41) were randomized in four groups sacrificed at day one, 1, 6, and 12 months. Microcomputed tomography (microCT) allowed 3D morphometry of erosion of nacre. Osseointegration was measured as the volume of trabecular bone bone volume/tissue volume (BV/TV) in a standardized volume of interest around each screw. Undecalcified bone histology was also done. Gross examination revealed a similar clinical osseointegration for titanium and nacre screws. A progressive erosion of nacre screws, but no erosion of titanium screws, was observed in microCT. The volume of nacre screws progressively decreased over time whereas no modification occurred for titanium. For titanium screws, BV/TV remained stable throughout the study. For nacre screws, the BV/TV decrease was not statistically different. A significant difference was found between nacre and titanium screws at 6 months but not at 12 months. The screw heads, outside the bone shaft, were not eroded even after 12 months. Erosion of nacre occurred during the entire study period, only within the bone shaft in direct contact with bone marrow. Bone apposition was observed on nacre surfaces without signs of erosion. Nacre is a promising biomaterial in maxillofacial surgery.

Blending of PLGA-PEG-PLGA for Improving the Erosion and Drug Release Profile of PCL Microspheres

BACKGROUND

PCL has a long history as an industrialized biomaterial for preparing microspheres, but its hydrophobic property and slow degradation rate often cause drug degeneration, quite slow drug release rate and undesirable tri-phasic release profile.

MATERIALS AND METHODS

In this study, we used the blending material of PLGA-PEG-PLGA and PCL to prepare microspheres. The microspheres degradation and drug release behaviors were evaluated through their molecular weight reduction rate, mass loss rate, morphology erosion and drug release profile. The hydrophilic PLGA-PEG-PLGA is expected to improve the degradation and drug release behaviors of PCL microspheres.

RESULTS

Microspheres in blending materials exhibited faster erosion rates than pure PCL microspheres, forming holes much quickly on the particle's surface for the drug to diffuse out. A higher proportion of PLGA-PEG-PLGA caused faster degradation and erosion rates. The blending microspheres showed much faster drug release rates than pure PCL microspheres.

CONCLUSION

With blending of 25wt% PLGA-PEG-PLGA, the release rate of microspheres speeded up significantly, while, with a further increase of PLGA-PEG-PLGA proportion (50%, 75%, 100%), it accelerated a little. The microspheres with PCL/PLGA-PEG-PLGA of 1/1 exhibited a linear-like drug release profile. The results could be a guideline for preparing microspheres based on blending materials to obtain a desirable release.

Novel Ensemble Approach of Deep Learning Neural Network (DLNN) Model and Particle Swarm Optimization (PSO) Algorithm for Prediction of Gully Erosion Susceptibility

This study aims to evaluate a new approach in modeling gully erosion susceptibility (GES) based on a deep learning neural network (DLNN) model and an ensemble particle swarm optimization (PSO) algorithm with DLNN (PSO-DLNN), comparing these approaches with common artificial neural network (ANN) and support vector machine (SVM) models in Shirahan watershed, Iran. For this purpose, 13 independent variables affecting GES in the study area, namely, altitude, slope, aspect, plan curvature, profile curvature, drainage density, distance from a river, land use, soil, lithology, rainfall, stream power index (SPI), and topographic wetness index (TWI), were prepared. A total of 132 gully erosion locations were identified during field visits. To implement the proposed model, the dataset was divided into the two categories of training (70%) and testing (30%). The results indicate that the area under the curve (AUC) value from receiver operating characteristic (ROC) considering the testing datasets of PSO-DLNN is 0.89, which indicates superb accuracy. The rest of the models are associated with optimal accuracy and have similar results to the PSO-DLNN model; the AUC values from ROC of DLNN, SVM, and ANN for the testing datasets are 0.87, 0.85, and 0.84, respectively. The efficiency of the proposed model in terms of prediction of GES was increased. Therefore, it can be concluded that the DLNN model and its ensemble with the PSO algorithm can be used as a novel and practical method to predict gully erosion susceptibility, which can help planners and managers to manage and reduce the risk of this phenomenon.

[Erosion morphology and the characteristics of runoff and sediment yielding in platform-slope system of opencast coal mine]

In the open pit, runoff from the platform is large discharge and rapid afflux, which often results in serious gully erosion of dump slope. The study of erosion process under catchment conditions of the platform-slope system is still backward. In this study, field scouring experiments were conducted to investigate runoff characteristics and sediment yield processes of the platform-slope system under different flow discharges (48, 60, 72 and 84 L·min^-1). Our results showed that rill erosion dominated the platform-slope system under the flow discharge of 48 L·min^-1, and gully was formed under 60-84 L·min^-1. The flow velocity of the platform and the slope showed an abrupting-fluctuating-stable trend with the duration of discharge. The flow velocity of the platform was smaller than that of the slope, with the magnitude of reduction at 8.3%-67.1%. The highest flow velocity appeared on the up-slop/down-slope, being 18.5%-44.6% higher than that of the middle-slope. In general, the sediment yield rate of the platform and the slope varied with the duration of discharge, with the sediment yield rate of the slope being 17.4 times as that of the platform. The ratio of gully width to depth showed substantial difference between the platform and slope. The platform generally had the largest ratio than the slope. For the slope, the largest ratio appeared on the middle-slop/down-slope, being 1.36-1.93 times as that of the up-slope. The morphology of rill and gully along the platform to down-slope presented in the form of "wide and shallow-narrow and deep-wide and shallow". Rill erosion mainly concentrated in the platform and the middle slope under the flow discharge of 48 L·min^-1, contributed 29.9% and 26.8% of the total erosion volume, respectively. When the flow discharge increased to 60-84 L·min^-1, the largest average across-section areas (1083.25-1737.86 cm²) formed on the up-slope accounted for 36.1%-44.7% of the total erosion volume. Our results provided evidence for modelling soil and water erosion of the platform-slope system in opencast coal mine.

Seagrass losses since mid-20th century fuelled CO2 emissions from soil carbon stocks

Seagrass meadows store globally significant organic carbon (C_org ) stocks which, if disturbed, can lead to CO₂ emissions, contributing to climate change. Eutrophication and thermal stress continue to be a major cause of seagrass decline worldwide, but the associated CO₂ emissions remain poorly understood. This study presents comprehensive estimates of seagrass soil C_org erosion following eutrophication-driven seagrass loss in Cockburn Sound (23 km² between 1960s and 1990s) and identifies the main drivers. We estimate that shallow seagrass meadows (<5 m depth) had significantly higher C_org stocks in 50 cm thick soils (4.5 ± 0.7 kg C_org /m² ) than previously vegetated counterparts (0.5 ± 0.1 kg C_org /m² ). In deeper areas (>5 m), however, soil C_org stocks in seagrass and bare but previously vegetated areas were not significantly different (2.6 ± 0.3 and 3.0 ± 0.6 kg C_org /m² , respectively). The soil C_org sequestration capacity prevailed in shallow and deep vegetated areas (55 ± 11 and 21 ± 7 g C_org  m^-2  year^-1 , respectively), but was lost in bare areas. We identified that seagrass canopy loss alone does not necessarily drive changes in soil C_org but, when combined with high hydrodynamic energy, significant erosion occurred. Our estimates point at ~0.20 m/s as the critical shear velocity threshold causing soil C_org erosion. We estimate, from field studies and satellite imagery, that soil C_org erosion (within the top 50 cm) following seagrass loss likely resulted in cumulative emissions of 0.06-0.14 Tg CO_2-eq over the last 40 years in Cockburn Sound. We estimated that indirect impacts (i.e. eutrophication, thermal stress and light stress) causing the loss of ~161,150 ha of seagrasses in Australia, likely resulted in the release of 11-21 Tg CO_{2 -eq} since the 1950s, increasing cumulative CO₂ emissions from land-use change in Australia by 1.1%-2.3% per annum. The patterns described serve as a baseline to estimate potential CO₂ emissions following disturbance of seagrass meadows.

Effect of erosive and abrasive challenges on the glaze layer applied to ceramic materials

PURPOSE

This study aims to evaluate the effect of erosive, abrasive, and erosive/abrasive challenges on the glaze layer of ceramic materials.

METHODS

Ninety-five samples of monolithic zirconia (MZ) (LuxaCam Zircon HT-Plus) and lithium disilicate (LD) (IPS e.max CAD) were divided according to the response variables: Surface roughness and surface loss (n = 10), evaluated with optical profilometry; surface topography, with scanning electron microscopy SEM (n = 3); and biofilm deposition, with microbiological assay (n = 5). The evaluations were performed in three different time evaluations: (a) Sintered, (b) Glaze, and (c) Challenge (Erosion, Abrasion, and Erosion/Abrasion). Erosion consisted in immersing specimens in HCl solution, abrasion was performed with brushing machine, and erosion/abrasion consisted of a combination of the two previous protocols. Data were analyzed with parametric tests (P < 0.05).

RESULTS

MZ glaze layer presented significantly higher surface roughness (P = 0.00), surface loss (P = 0.03), and biofilm deposition (P = 0.00) than LD. Abrasion and erosion/abrasion showed similar outcomes, generating significantly higher surface roughness (P = 0.00), surface loss (P = 0.00), and biofilm deposition (P = 0.01) than erosion.

CONCLUSIONS

Glaze layer properties were altered by the challenges, with abrasion and erosion/abrasion generating higher surface roughness, surface loss, and biofilm deposition than erosion. A significant correlation was found between the surface roughness and biofilm deposition.

CLINICAL SIGNIFICANCE

The glaze layer is susceptible to challenges, especially to abrasion and erosion/abrasion, which generated greater surface roughness and surface loss than erosion. The greater surface roughness lead to a greater biofilm deposition on the glaze layer.