Alternative Fillers in Asphalt Concrete Mixtures: Laboratory Investigation and Machine Learning Modeling towards Mechanical Performance Prediction.

In recent years, due to the reduction in available natural resources, the attention of many researchers has been focused on the reuse of recycled materials and industrial waste in common engineering applications. This paper discusses the feasibility of using seven different materials as alternative fillers instead of ordinary Portland cement (OPC) in road pavement base layers: namely rice husk ash (RHA), brick dust (BD), marble dust (MD), stone dust (SD), fly ash (FA), limestone dust (LD), and silica fume (SF). To exclusively evaluate the effect that selected fillers had on the mechanical performance of asphalt mixtures, we carried out Marshall, indirect tensile strength, moisture susceptibility, and Cantabro abrasion loss tests on specimens in which only the filler type and its percentage varied while keeping constant all the remaining design parameters. Experimental findings showed that all mixtures, except those prepared with 4% RHA or MD, met the requirements of Indian standards with respect to air voids, Marshall stability and quotient. LD and SF mixtures provided slightly better mechanical strength and durability than OPC ones, proving they can be successfully recycled as filler in asphalt mixtures. Furthermore, a Machine Learning methodology based on laboratory results was developed. A decision tree Categorical Boosting approach allowed the main mechanical properties of the investigated mixtures to be predicted on the basis of the main compositional variables, with a mean Pearson correlation and a mean coefficient of determination equal to 0.9724 and 0.9374, respectively.

An experimental study on strength improvement of expansive subgrades by polypropylene fibers and geogrid reinforcement.

The rapid development of infrastructure often encounters the loose subgrades and is becoming difficult to carry to construction activities. Numerous counteracting methods are developed to control the swelling-shrinkage behavior of the expansive subgrades. The mechanical stabilization of the expansive subgrades by reinforcing with the polypropylene fiber and geogrid is sustainable. Geogrids and polypropylene fibers have been used extensively to strengthen the expansive subgrade and foundations as individuals. The polypropylene fiber reinforcement enhanced the reinforced expansive subgrades's tensile strength capacity, wherein the geogrid reinforcement is the quick fix mechanical stabilization technique, which reduces the pavement failures. In this research, the polypropylene fiber and geogrid reinforcement's combined effect has been evaluated to stabilize the pavement subgrades. The various mechanical strength test such as unconfined compressive strength (UCS) and large direct shear box test was conducted to evaluate the mechanical interaction between expansive subgrades, polypropylene fiber, triaxial geogrid, and biaxial geogrid at the interface. The polypropylene fiber of 12 mm length was used in the proportion of 0.25%, 0.5%, and 1.0% and single geogrid layer at mid-depth. The result shows that reinforced subgrades' shear strength with a layer of biaxial/ triaxial geogrid and polypropylene fiber increases by 177%. It is also observed that the unconfined compressive strength of the expansive subgrades increased ranging 3.8-139.6% with the inclusion of polypropylene fiber with geogrid in different combinations. The combined reinforcement method shows an effective treatment methodology to improve the property of expansive subgrades.

Micro-mechanical performance evaluation of expansive soil biotreated with indigenous bacteria using MICP method.

This study explored the effect of indigenous bacteria present in the soil to stabilized swelling behavior and improving the mechanical property of expansive soil. The objective of the research is to investigate the effectiveness of the biostimulation microbial induced calcite precipitation (MICP) for controlling the swelling-shrinkage behavior and improving shear strength of expansive soil. An attempt was made to develop an effective procedure to culture the indigenous bacteria for treating clays with varying plasticity and improve their engineering behavior. The detailed procedure has been investigated to effectively apply the MICP technique in clay soil, considering its low permeable nature. The applicability of biostimulation to clayey soils in minimizing their swelling potential and improving the strength is assessed. Both macroscale and microscale studies were conducted on untreated and biostimulated soils to observe changes in plasticity, strength, swelling, mineralogical, chemical characteristics. The present method has shown an effective alternative to improve the road pavement subgrade without affecting the eco-system of natural soil. The method investigated the effective way of providing the enrichment and cementation solution in clayey soil, which is the major concern in current literature. The study confirms that the calcite content has been increased with biostimulated MICP treatment up to 205% in the treated specimens and which future increased the unconfined compressive strength and split tensile strength. A reduction in the swelling pressure and swell strain is also observed. The results show that a cost-effect and eco-friendly method can be deployed for stabilizing the road pavement subgrades. The statistical assessment using multivariate analysis and hierarchical clustering dendrogram has been carried out to investigate the effect of the MICP treatment protocol on different soil and engineering parameters.

Anetoderma in a Patient with Newly Diagnosed Hodgkin's Lymphoma.

A previously healthy 28-year-old woman was admitted to the hospital with respiratory failure and was found to have significant lymphadenopathy on her CT scan. A lymph node biopsy was performed; the pathology was consistent with a diagnosis of Hodgkin's lymphoma and the patient was noted to have multiple, wrinkled, nonscaly, oval-shaped papules that were easily compressible (Figure 1) and were present on the upper and lower extremities, abdomen, chest, and back. The lesions were entirely asymptomatic and had first developed 1 year prior to presentation. Since their initial development, the wrinkled papules had continued to crop up. Some of the lesions began as brownish-red papules and subsequently turned skin-colored.Punch biopsies of the lesional and unaffected skin were performed. A Verhoeff-Van Gieson (VVG) stain showed loss of dermal elastic tissue in the lesional skin, compared to that of the unaffected skin. The clinical and histologic examinations were consistent with the diagnosis of anetoderma.

Effect of Curing on Micro-Physical Performance of Polypropylene Fiber Reinforced and Silica Fume stabilized Expansive Soil Under Freezing Thawing Cycles.

This study presents the micro-physical investigation of polypropylene (PP) fiber-reinforced, and silica fume (SF) stabilized expansive soil (BC) subgrade. The coupling effect of soil, PP fiber, and SF has been evaluated under the freezing-thawing (F-T) cycle to assess the durability of treated BC Soil. The curing method and duration staggeringly influence the strength of SF treated BC soil; therefore, three different curing method, i.e., moisture-controlled curing (MC), gunny bag curing (GC), and water submerged curing (SC) to a period of 7, 14, and 28 days were considered. The BC soil has been reinforced with 0.25%, 0.50%, and 1.00% PP fiber and stabilized with 2%, 4%, 6% and 8% SF. The physical, chemical, and microstructural properties were determined before and after 2,4,6,8,10 F-T cycles. With the increase in SF content, the unconfined compressive strength of the expansive soil has been increased due to the formation of Calcium Silicate Hydrate (C-S-H) gel. The chemically inert, hydrophobic, non-corrosive nature, and higher tensile strength of PP fiber, it has a higher potential to reinforce the BC soil for durability under tensile failure. This research confirms the possibility of incorporating SF and PP Fiber in road work applications, with significant environmental benefits.

Profile of infectious and sterile keratitis after accelerated corneal collagen cross-linking for keratoconus.

PURPOSE: The aim of this study was to assess the potential risk factors and causes of infectious and sterile keratitis after accelerated collagen cross-linking. METHODS: Case records of 968 eyes that underwent accelerated corneal collagen cross-linking (ACXL) over the period of 4 years were reviewed retrospectively. ACXL was done using (Avedro KXL® system, Waltham, MA, USA) 9 mW/cm2 for 10 min protocol providing total energy of 5.4 J/cm2. RESULTS: Of 968 eyes, a total of three eyes developed infectious keratitis and seven eyes developed sterile infiltrates. Three of this infectious keratitis had two cases which were resistant to fourth-generation fluoroquinolones. Seven cases of sterile infiltrates had excellent resolution after treatment with topical steroids. Sterile infiltrates were common in corneas with thinnest pachymetry of <400 µm, except in one case of intra stromal corneal ring segments (INTACS) + ACXL. CONCLUSION: Judicious use of steroids in the initial postoperative period is recommended so as to prevent any form of microbial keratitis. Very steep corneas and too thin corneas should be looked with high index of suspicion in view of chances of developing sterile infiltrates.

Linear porokeratosis associated with Bardet-Biedl syndrome: A case report.

This case report presents a 17-year-old boy with Bardet-Biedl syndrome (BBS) and a long-standing hyperpigmented eruption on the left trunk and upper extremity, clinically and histologically consistent with linear porokeratosis (LP). BBS patients frequently require solid organ transplant, and subsequent immunosuppression places them at especially high risk for malignant transformation of premalignant skin lesions such as LP. Although BBS affects multiple organ systems, there are only a handful of case reports detailing associated cutaneous involvement, and, to our knowledge, this is the first reported case of linear porokeratosis occurring in patient with BBS.

Long-term analysis of an unconventional way of doing double-head pterygium excision.

AIM: The aim of the study is to describe an unconventional technique of vertically split conjunctival autograft (CAG) for primary double-head pterygium and its long-term outcome. MATERIALS AND METHODS: This was a retrospective, noncomparative, interventional case series of 95 eyes of 95 patients, who underwent vertical, split CAG surgery without maintaining limbus-limbus orientation for primary double-head pterygium from January 2013 to January 2017. All patients were reviewed for recurrence in their follow-up period. RESULTS: The mean follow-up was 14.12 ± 9.42 months. The baseline characteristics included 44 males and 51 females, with a mean age of 56.24 ± 10.03 years. The only significant complication was recurrence rate of 2.10% (2 eyes out of 95). The most common secondary outcome was graft edema (36.84%, 35 eyes out of 95), which resolved without any intervention. The other outcomes such as graft retraction (12.63%), Tenon's granuloma (1.05%), and subconjunctival hemorrhage (34.73%) were also recorded. CONCLUSION: Unconventional vertical split CAG without maintaining limbus-limbus orientation has convincing results in treating double-head pterygium with lower recurrence rate.

Comparative analysis of visual outcomes and ocular aberrations following wavefront optimized and topography-guided customized femtosecond laser in situ keratomileusis for myopia and myopic astigmatism: A contralateral eye study.

PURPOSE: To compare the visual outcomes and higher order aberrations (HOAs) following wavefront optimized (WFO) laser in situ keratomileusis (LASIK) versus topography-guided customized ablation (TCAT) LASIK for myopia and myopic astigmatism. METHODS: Patients who underwent femtosecond-assisted LASIK for myopic correction between August 2016 and October 2017 were included in this interventional prospective case series. The following parameters were evaluated preoperatively and at 3 months' postoperative visit: uncorrected distance vision acuity (UDVA) and corrected distance vision acuity (CDVA), manifest refraction, and HOAs. RESULTS: Two hundred eyes of 100 patients were included in the study. At 3 months' postoperative visit, 92% and 90% eyes in the TCAT and WFO groups, respectively, demonstrated a UDVA of 20/20 or better (P = 0.90). A residual manifest spherical equivalent within 0.5 D was achieved in 100% and 95% of the eyes in the TCAT and WFO groups, respectively (P = 0.10). No significant difference was observed in the HOAs induced in both the groups, with slightly lower induction of trefoil and horizontal coma in the TCAT group. CONCLUSION: Both groups demonstrated similar refractive efficacy and predictability, with greater gain of CDVA following TCAT ablation. HOAs induced were not significantly different between the two groups. Further studies are needed to validate the superiority of one procedure over the other.

Concomitant use of conjunctival tissue graft from the pterygium itself without rotation in pterygium surgery: A full circle in conjunctival autografting.

Purpose: The aim of this study is to describe a modified technique of using conjunctival tissue from the pterygium itself without any rotation of graft for the primary pterygium in eyes with glaucoma filtering bleb, glaucoma suspects, and in primary double-head pterygium using fibrin glue. Methods: In this retrospective, noncomparative, interventional case series, 98 eyes of 98 patients with primary pterygium operated between July 2011 to July 2016 were included. They underwent this technique from the pterygium tissue itself. There was no rotation of this graft, and it was adhered to the bare scleral defect with fibrin glue. Histopathological analysis of pterygium tissue was done to look for morphology and thickness of this thin conjunctival tissue obtained from pterygium tissue itself. The primary outcome measure was recurrence rate. Other outcome measures studied was graft retraction and graft edema. Results: The mean age was 52 ± 10.04 years. Mean follow-up was 14 ± 8.24 months. The only significant complication was recurrence rate of 4.08% (4 eyes out of 98). The most come secondary outcome was graft edema, 52.04% (51 eyes out of 98) which resolved without any intervention. Other outcome such as graft retraction, 32.65% was also recorded. Conclusion: Conjunctival tissue from the pterygium tissue itself without actual rotation appears to be a successful technique with lower recurrence rate for treating primary pterygium in eyes with glaucoma filtering bleb, glaucoma suspects, and in primary double-head pterygium.

Double-head pterygium excision with modified vertically split-conjunctival autograft: Six-year long-term retrospective analysis.

PURPOSE: The aim of this study is to describe a modified technique of vertically split-conjunctival autograft (CAG) for primary double-head pterygium and evaluate its postoperative outcome. METHODS: In this retrospective, noncomparative, interventional case series, 87 eyes of 87 patients of double-head pterygium from June 2009 to June 2015 were included. They underwent vertical split CAG. A limbus-limbus orientation was not strictly maintained. Primary outcome measure was recurrence rate. Other outcome measures studied were graft retraction, Tenon's granuloma, dellen, and so on. RESULTS: Mean age was 54.54 ± 11.51 years; M:F was 41:46. Mean follow-up was 17.28 ± 10.28 months. The only significant complication was recurrence rate of 3.45% (3 eyes out of 87). Other most common secondary outcome was graft edema, 42.52% (37 eyes out of 87) which resolved without any intervention. Other outcomes such as graft retraction (31.03%), dellen (1.15%), Tenon's granuloma (3.45%), and subconjunctival hemorrhage (36.78%) were recorded. CONCLUSION: Modified vertical split CAG without maintaining limbus-limbus orientation, just large enough to cover the bare scleral defect, appears to be a successful technique with lower recurrence rate in treating double-head pterygium.

On the kinetics of body versus end evaporation and addition of supramolecular polymers.

The kinetics of the self-assembly of supramolecular polymers is dictated by how monomers, dimers, trimers etc., attach to and detach from each other. It is for this reasons that researchers have proposed a plethora of pathways to explain the kinetics of various self-assembling supramolecules, including sulfur, linear micelles, living polymers and protein fibrils. Recent observations hint at the importance of a hitherto ignored molecular aggregation pathway that we refer to as "body evaporation and addition". In this pathway, monomers can enter at or dissociate from any point along the backbone of the polymer. In this paper, we compare predictions for the well-established end evaporation and addition pathway with those that we obtained for the newly proposed body evaporation and addition model. We quantify the lag time, characteristic of nucleated reversible polymerisation, in terms of the time it takes to obtain half of the steady-state polymerised fraction and the apparent growth rate at that point, and obtain power laws for both as a function of the total monomer concentration. We find, perhaps not entirely unexpectedly, that the body evaporation and addition pathway speeds up the relaxation of the polymerised monomeric mass relative to that of the end evaporation and addition. However, the presence of the body evaporation and addition pathway does not affect the dependence of the lag time on the total monomer concentration and it remains the same as that for the case of end evaporation and addition. The scaling of the lag time with the forward rate is different for the two models, suggesting that they may be distinguished experimentally.

Aortic Endograft and Epithelioid Sarcoma: A Random Association or Causality?

BACKGROUND: Angiosarcoma is an uncommon, malignant neoplasm often found in skin and soft tissue. Epithelioid angiosarcoma (EA) is a rarer, more aggressive form of angiosarcoma most common in men in their seventh decade. Dacron®, a polymer comprised of polyethylene terephthalate used in endografts for abdominal aortic aneurysm repairs, has been a suspected carcinogen associated with EA. Currently, three case reports exist in the literature purporting Dacron®-associated epithelioid angiosarcoma. Herein we report a case of Dacron®-associated EA.
CASE: A 64-year-old male with a recent history of a repaired type 2 endoleak and Dacron® endograft for his AAA presented with a painful skin eruption, fever, and weight loss. On exam, erythematous and violaceous papules and nodules were present on the patient's lower back. Biopsy revealed atypical, epithelioid cells forming vascular channels in a sheet-like and infiltrative pattern. These results and subsequent immunostaining were consistent with the diagnosis of EA. A bone marrow biopsy confirmed metastatic angiosarcoma.
CONCLUSION: This case further highlights Dacron® as a rare, but, potential carcinogen associated with EA.

J Drugs Dermatol. 2016;15(7):897-899.

Stochastic lag time in nucleated linear self-assembly.

Protein aggregation is of great importance in biology, e.g., in amyloid fibrillation. The aggregation processes that occur at the cellular scale must be highly stochastic in nature because of the statistical number fluctuations that arise on account of the small system size at the cellular scale. We study the nucleated reversible self-assembly of monomeric building blocks into polymer-like aggregates using the method of kinetic Monte Carlo. Kinetic Monte Carlo, being inherently stochastic, allows us to study the impact of fluctuations on the polymerization reactions. One of the most important characteristic features in this kind of problem is the existence of a lag phase before self-assembly takes off, which is what we focus attention on. We study the associated lag time as a function of system size and kinetic pathway. We find that the leading order stochastic contribution to the lag time before polymerization commences is inversely proportional to the system volume for large-enough system size for all nine reaction pathways tested. Finite-size corrections to this do depend on the kinetic pathway.

Dynamic Landau theory for supramolecular self-assembly.

Although pathway-specific kinetic theories are fundamentally important to describe and understand reversible polymerisation kinetics, they come in principle at a cost of having a large number of system-specific parameters. Here, we construct a dynamical Landau theory to describe the kinetics of activated linear supramolecular self-assembly, which drastically reduces the number of parameters and still describes most of the interesting and generic behavior of the system in hand. This phenomenological approach hinges on the fact that if nucleated, the polymerisation transition resembles a phase transition. We are able to describe hysteresis, overshooting, undershooting and the existence of a lag time before polymerisation takes off, and pinpoint the conditions required for observing these types of phenomenon in the assembly and disassembly kinetics. We argue that the phenomenological kinetic parameter in our theory is a pathway controller, i.e., it controls the relative weights of the molecular pathways through which self-assembly takes place.