Multiple Erosion Research Articles

A Novel Simulation Model for Multiple Solid Particle Erosion in Micro-blasting Process of Ti-6Al-4V Dental Implant Alloy Considering Actual Geometry of Impacting Particles

A Novel Simulation Model for Multiple Solid Particle Erosion in Micro-blasting Process of Ti-6Al-4V Dental Implant Alloy Considering Actual Geometry of Impacting Particles

Green and Low-Cost Modified Pisha Sandstone Geopolymer Gel Materials for Ecological Restoration: A Phase Review.

Pisha sandstone (PS) is a special interbedded rock in the middle reaches of the Yellow River that experiences severe weathering and is loose and broken. Due to severe multiple erosion events, the Pisha sandstone region is called "the most severe water loss and soil erosion in the world" and "the ecological cancer of the earth". As a special pozzolanic mineral, PS has the potential to be used as precursors for the synthesis of green and low-carbon geopolymer gel materials and applied in ecological restoration. This paper aims to undertake a phase review of the precursors for geopolymer gel materials. The genesis and distribution, physical and chemical characterization, erosion characteristics, and advances in the ecological restoration of PS are all summarized. Furthermore, current advances in the use of PS for the synthesis of geopolymer gel materials in terms of mechanical properties and durability are discussed. The production of Pisha sandstone geopolymer gels through the binder jetting technique and 3D printing techniques is prospected. Meanwhile, the prospects for the resource application of PS in mine rehabilitation and sustainable ecology are discussed. In the future, multifactor-driven comprehensive measures should be further investigated in order to achieve ecological restoration of the Pisha sandstone region and promote high-quality development of the Yellow River Basin.

Cystitis glandularis with concomitant Crohn’s disease leading to a paroxysm of Crohn’s disease with ulcerated external iliac vessels

•we report the case of a 36-year-old female patient who presented to our hospital with a diagnosis of cystitis glandularis manifesting as a vesicovaginal fistula. She underwent cystoscopic biopsy at a local hospital, but anti-inflammatory treatment was ineffective, and the patient was experiencing low urination frequency and urgency, as well as pain. The patient underwent laparoscopic repair of a cystoscopy-confirmed vesicovaginal fistula. After surgery, the patient experienced a paroxysm of Crohn’s disease with multiple small bowel fistulas and erosion of the external iliac vessels that ruptured to form an external iliac vessel small bowel fistula. The fistula was confirmed by surgical exploration, and the patient eventually died.

Investigation of the Mechanical Behaviors and Damage Mechanism of C/C Composites Impacted by High-Velocity Jets.

Carbon/Carbon (C/C) composites exhibit excellent mechanical properties at high temperatures, making them widely used in aerospace, such as the leading edges of spaceplane wings and the nose cones of hypersonic aircraft. However, damage caused by rain erosion to C/C composites affects their mechanical properties and poses significant challenges during operational service periods. A jet impingement test platform was employed to conduct single and multiple water-jet erosion tests on three-dimensional orthogonal C/C composite materials and to investigate the residual mechanical properties of the specimens after jet impact. The damage was characterized using optical microscopy, scanning electron microscopy, and X-ray computed tomography. The results showed that the damage types of the C/C composite materials under water-jet impingement included fiber bundle fracturing, delamination, and debonding. The extent of erosion damage was positively correlated with the jet velocity and diameter. The changes in the multi-jet damage indicated a cumulative expansion process, and z-directional fiber bundles exhibited superior resistance to jet impact damage propagation. The results of the three-point bending tests showed that the greater the initial impact damage, the lower the residual mechanical properties of the materials, and the residual strength of the specimen suddenly decreased when damage occurred at the back of the specimen.

Assessment of Soil Erosion Susceptibility, Spatial Sediment Delivery Processes and Control Strategies at the Nzoia River Catchment in Kenya

The Nzoia basin is among the most densely populated regions in Western Kenya, with an average density of up to 450 people per square kilometre. Cereal farming accounts for over half of the land usage in the basin. The massive conversion of land from forest to cropland and grassland in the region has significantly impacted soil erosion and reduced soil fertility. Several studies have been undertaken in the catchment, principally on potential soil loss; however, no extensive research has been conducted on the spatial sediment delivery processes or on establishing the best land management practices for the catchment. This study simulates the basin’s susceptibility to erosion using the RUSLE model, examines the spatial sediment delivery process, and undertakes scenario analysis to establish the best erosion control practices for the catchment. The RUSLE factors were combined in ILWIS GIS to create functions for soil erosion and sediment transport capacity, which were applied to compute the potential annual soil loss for each pixel. The formulated sediment routing algorithm directed the sediments toward the river and the lake. The results from the study show that potential annual soil loss varied from 0.00 in the lowlands to 4,577 tonnes/ha/year in the highland areas, with the catchment’s total potential soil loss estimated at 8,380,000 tonnes/year. The basin’s sediment yield at Lake Victoria was 2,494,575 tons/year, translating to a sediment delivery ratio of about 29%. The cropland regions were the dominant contributors of eroded sediments. The scenario analysis applied practical agronomic and mechanical erosion control methods to croplands, demonstrating that adopting multiple soil erosion control strategies could effectively reduce soil loss across the catchment. Areas with high erosion are primarily found in the sloping regions of the catchment, especially around Mt. Elgon, Chereng’anyi Hills, Kipkaren, and Kapsokwony. The spatial soil erosion and deposition hazard maps generated in this study should be used as practical guides for combating land degradation in the Nzoia River catchment.

Shallow‐marine calciclastic mass‐transport deposits in an evolving thrust‐top basin: A case study from the North Dalmatian foreland basin, Croatia

AbstractMass‐transport deposits are products of resedimentation phenomena involving a broad spectrum of gravity‐driven processes, and commonly have a high preservation potential in deep‐marine environments. This study documents various types of mass‐transport deposits that are interbedded with intensely bioturbated shallow‐marine calciclastic sediments deposited along a reflective coast during the middle and late Eocene. The sedimentary succession, located in the vicinity of Novigrad in northern Dalmatia, Croatia, comprises sediments deposited in a range of nearshore and carbonate ramp environments, and represents the infill of a thrust‐top (piggyback) basin of the North Dalmatian foreland basin. Five types of mass‐transport deposits, ranging in thickness from 13 cm to 6 m, have been identified: (i) calcilutite and calcarenite slumps; (ii) conglomeratic slump‐debrites with a ‘dough‐like’ appearance; (iii) blocky‐flow deposits bearing large blocks of beachface and/or shoreface deposits; (iv) rockfall deposits comprising scattered blocks of beachface conglomerates and shoreface calcarenites; and (v) ‘classical’ matrix‐supported debrites. Calciturbidites are rare and mainly comprise Ta and Tb divisions. Conglomeratic slump‐debrites are mostly found in association with offshore‐transition deposits, suggesting that mass flows were triggered above the storm‐wave base likely due to a combined effect of: (i) strong earthquakes related to the tectonic development of the basin; (ii) sediment destabilization due to pore‐water overpressure during forced regressions; and (iii) storm‐wave loading affecting the shallow seabed. Progressive deepening likely favoured mass‐flow transformations, although the overall paucity of turbidites suggests relatively short mass‐flow transport distance and turbidity current bypass to deeper realms. Multiple erosion phases and resedimentation processes from the Cretaceous to the late Eocene contributed to the diverse suite of extraformational clasts in the mass‐transport deposits studied. The mass‐transport deposits may be triggered and emplaced in shallow‐marine settings mainly during regressive stages of basin development, as the diverse gravel clast composition suggests significant tectonic influence. Although the mass‐transport deposits reported herein are relatively small, some of their peculiar sedimentary features and occurrence within shallow‐marine calciclastic deposits render them rather unique and suitable for a re‐assessment of the nature and evolutionary continuum of processes involved in subaqueous sediment mass transport, as well as the preservation potential of sedimentary features in high‐energy wave‐reworked environments.

Towards a better understanding of pathways of multiple co-occurring erosion processes on global cropland

Soil erosion is a complex process involving multiple natural and anthropic agents, causing the deterioration of multiple components comprising soil health. Here, we provide an estimate of the spatial patterns of cropland susceptibility to erosion by sheet and rill, gully, wind, tillage, and root crops harvesting and report the co-occurrence of these processes using a multi-model approach. In addition, to give a global overview of potential future changes, we identify the locations where these multiple concurrent soil erosion processes may be expected to intersect with projected dry/wet climate changes by 2070. Of a modelled 1.48 billion hectares (B ha) of global cropland, our results indicate that 0.56 B ha (∼36% of the total area) are highly susceptible (classes 4 and 5) to a single erosion process, 0.27 B ha (∼18% of the total area) to two processes and 0.02 B ha (1.4% of the total area) to three or more processes. An estimated 0.82 B ha of croplands are susceptible to possible increases in water (0.68 B ha) and wind (0.14 B ha) erosion. We contend that the presented set of estimates represents a basis for enhancing our foundational knowledge on the geography of soil erosion at the global scale. The generated insight on multiple erosion processes can be a useful starting point for decision-makers working with ex-post and ex-ante policy evaluation of the UN Sustainable Development Goal 15 (Life on Land) activities. Scientifically, this work provides the hitherto most comprehensive assessment of soil erosion risks at the global scale, based on state-of-the-art models.

Anatomical and Histological Evidence of Aluminum Bone Toxicity: An Experimental Study

Objectives: Aluminum has may be cytotoxic to animals and humans. It is mainly stored in bone and unfortunately, its absorption is increased with age. This study is done to define possible aluminum pathological changes in bone of aging albino rats. Methods: Twenty male albino rats aged 24 months was divided into two groups, control experimental. Experimental group received aluminum chloride for 10 weeks orally. The femur of both control and experimental group is investigated by light and electron microscope. Plain X-ray to the femur as an example to bone is also done. Results: Plain X-ray of femurs of the experimental group showed medullary bone trabeculae destruction, cortical bone resorption and sclerosis. Sections of the shaft of the femur stained with H&E confirmed X-ray gross picture and the bony cortex appeared very thin in comparison with control and showed multiple erosion cavities that may leads to bone fractures. Bone cells appeared few and highly degenerated while the periosteum was very thin and detached from the bone cortex. The bone trabeculae were highly destroyed, and the wide bone marrow spaces were filled by fat cells in some bones. At the level of electron microscope, both osteocytes and osteoblasts revealed severe degenerative changes and showed few irregular collagenous matrices. Conclusion: The degenerative changes observed in the bone of this study are most probably due to aluminum ingestion.

Evaluation of Anti-Inflammatory and Anti-Arthritic Activities of AV11-03 in Female Rats

Rheumatiod arthritis is a systemic auto-immune disease characterized by chronic inflammation at multiple synovial joints, cartilage destruction and bone erosion. Currently available non-steroidal anti-inflammatory drugs, cortico-steroids and disease modifying anti-rheumatic therapies have severe side effects on prolonged use and thus throw a challenge for development of safe, effective alternatives. Of the many plant drugs claimed to be effective in the treatment of rheumatoid arthritis, in depth studies were carried out on the fruits of Terminalia chebula (Haradae) and the oleo-gum resin of Boswellia serrata (Sallaki). Glucosamine was shown to be chondrio-protective and effective in osteo-arthritis. Hence, we tested ‘AV-11 03’ which is a combination of the extracts of haradae, salliki an maize glucosamine on acute and chronic inflammatory models by studying a battery of physical, biochemical, histological and radiological parameters.

A rare case of diffuse penile phytocontact dermatitis caused by common greenbrier

Penis size has always been a considerable concern to a lot of men. Many men look for ways to increase their penile size, ranging from oral medication, stretch apparatus, injections, and surgery, to traditional methods. Smilax rotundifolia, also known as daun bungkus or common greenbrier in the western hemisphere, is a local herb most found in the West Papua region of Indonesia. This plant has been used for a variety of medicinal purposes but has recently gained fame as a novel penis enlargement. However, these claims have not been scientifically proven. A 25-year-old male presented with an ill-defined erythematous patch with multiple geographic erosion and diffuse edema after using a local herb called S. rotundifolia, also known as daun bungkus or common greenbrier. The patient was treated with an oral antihistamine, topical corticosteroids, and antibiotics. The condition improved within 2 weeks. S. rotundifulia, also known as daun bungkus, is a local herb from Papua, Indonesia, believed to have penis-enlargement properties. Research is still scarce on the active ingredients in this plant, and one study suggests that it contains triterpenoid saponin and saponin steroid. The active ingredients in this plant may be responsible for the development of contact dermatitis. Due to the popularity of this plant as an alternative penis augmentation product, it is important for practitioners to be aware of this product and its adverse effects. Further studies are also needed to examine the active ingredients in this plant.

Pycnodysostosis- A Rare Diagnosis Not to Miss

Introduction: Pycnodysostosis derived from the Greek words pycnos-density, dys-defect, ostosis-bone is a rare inherited disorder of the bone with an incidence of 1.7 per million births. It is one of the lysosomal storage disorders with a deficiency of enzyme cathepsin K. Along with a history of repeated fractures of the bones, patients with Pycnodysostosis have a short stature, dolichocephalic skull, obtuse mandibular angle, short terminal phalanx. They also have dental abnormalities such as the delayed eruption of permanent teeth, and double rows of teeth. Mild psychomotor problems were noted in a few individuals. Pycnodysostosis is diagnosed by clinical and radiological features as there is no diagnostic criterion. Skulls show open fontanels, generalized osteosclerosis, loss of the normal angle of the jaw, and hypoplasia of facial bones. Social and occupational support needed to prevent recurrent fractures. Orthopaedic and orthodontic cares are needed. Case: A non-diabetic normotensive male of 63 years presented to the medicine outpatients department (OPD) with complaints of burning type, non-radiating moderate intensity pain in the epigastric region for three months following taking of NSAIDs. He gave a history of fractures of different bones following minimal trauma since his childhood and used to take NSAIDs every now and then. He did take orthopaedic consultation for those fractures but the underlying pathophysiology was not explored. Malunion of long bones resulted in a deformed limb. The rest of his past medical history and family history was unremarkable. On clinical examination, we found the patient had short stature with proportionately short limbs. He had dysmorphic features with a large head, small facial structures, frontal and bilateral parietal bossing. Examination of the oral cavity revealed a narrow high arched palate and hypoplastic, overcrowded teeth. His digits were short and stubby. The lower limbs of the patient have angular deformities that resulted from malunion of bones from previous fracture. Haematological and biochemical investigations were normal. Chest X-ray showed multiple ribs fracture on the right side. The patient's clavicle was normal in X-ray. Both tibia and fibula showed a malunited fracture in diaphysis. Computed tomography (CT) of the skull, as well as 3D reconstruction of CT, found open fontanelles and widening of sutures (Figure). Frontal and parietal bossing was noted. There was hypoplasia of the air sinuses. CT scans showed dysplasia of the bones of the face and hands. Hypoplasia was noted in the terminal phalanx of fingers. An endoscopy of the upper gastrointestinal tract found multiple erosion around the antrum of the stomach. Considering the clinical and radiological feature diagnosis of Pycnodysostosis with NSAIDs-induced antral erosion was made. The patient and his caregivers were briefed about the diagnosis. Consultation from a multidisciplinary team was done concerning his treatment. Conclusion: It is important to diagnose Pycnodysostosis early as it allows proper planning to prevent future fractures. While assessing a patient with short stature with a history of repeated bone fracture Pycnodysostosis should be considered along with other differentials.

Policy implications of multiple concurrent soil erosion processes in European farmland

Policy implications of multiple concurrent soil erosion processes in European farmland

Investigation of boron distribution and material migration on the W7-X divertor by picosecond LIBS

One set of horizontal target elements of the Test Divertor Units (TDU), retrieved from the Wendelstein 7-X (W7-X) vessel after the end of second divertor Operation Phase (OP1.2B) in Hydrogen (H), were investigated by picosecond Laser-Induced Breakdown Spectroscopy (ps-LIBS). The Boron (B) distribution, H pattern and the material erosion/deposition pattern on these target elements were analyzed with high depth resolution and mapped in the poloidal direction of W7-X. From the spectroscopic analysis, B, H, Carbon (C) and Molybdenum (Mo) were clearly identified. A non-uniformly distributed B pattern on these divertor target elements was determined by the combination of B layer deposition during the three boronizations and W7-X plasma operation with multiple erosion and deposition steps of B. Like the TDU, the analyzed target elements are made of fine grain graphite, but have two marker layers which allow us to determine the material migration via the ps-LIBS technique. Two net erosion zones including one main erosion zone with a peak erosion depth of 6.5 μm and one weak erosion with a peak erosion of 1.3 μm were determined. Between two net erosion zones, a net deposition zone with width of 135 mm and a thickness up to 3.5 μm at the peak deposition location was determined by the ps-LIBS technique. The B distributions are correlated with the erosion/deposition pattern and the operational time in standard magnetic configuration of W7-X in the phases after the boronizations. The thickness of the containing B layer on these target elements also correlates with the erosion/deposition depth, in which the thickness of the containing B layer varies spatially in poloidal direction between 0.1 μm and 6 μm. Complementary, Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) was employed also to verify and investigate the deposition layer thicknesses at typical net erosion and net deposition zones as well as to identify the three boronizations in depth.

ASSESSMENT OF DENTAL STATUS OF PATIENTS WITH COVID-19

Abstract. Relevance. Most patients complain of a worsening of the oral cavity after a coronavirus infection. However, the state of the patient's dental status plays a special role in the dynamics of clinical symptoms in the oral cavity, since it is one of the criteria influencing the choice of treatment tactics by a dentist. Assessing the dental status of patients who have recovered from COVID-19 is an urgent task for clinicians. Purpose. To assess the dental status of patients undergoing COVID-19. Materials and methods. A dental examination was carried out on 48 patients aged 34 to 69 years with various diseases of the oral mucosa. The patients had a history of coronavirus infection from 2 to 6 months ago. When examining patients, clinical and laboratory methods were used. Results. Most of the patients experienced disturbances in terms of psycho-emotional status. On the mucous membrane of the lips, gums, cheeks, soft palate, pharynx and tongue, various manifestations were revealed: multiple aphthae, erosion, ulcers, plaque and plaques. The absence of oral cavity sanitation was noted - in 100% of cases. Conclusion. Correction of the dental status should be included in the treatment algorithm as a top priority to improve the efficiency of medical care for patients who have had coronavirus infection.

CMP Process Optimization Engineering by Machine Learning

Advanced Chemical-mechanical polishing (CMP) process not only needs to maintain stable run-to-run thickness control but also achieve better within wafer/within chip planarization performance. Furthermore, slurries or other consumable parts, like PAD and Disks selection are also the keys for CMP process optimization. The most difficult thing in CMP process is to have capability to predict and cover the various topologies and layout densities patterned wafers and preventing the hot spots occurrences. In this study, different Neural-Network algorithm with data pre-processing models are implemented to the in-line CMP CLC tuning and dishing/erosion prediction at various topology/pattern density test vehicle pattern wafers. Transfer learning technique is implemented on the original Neural -Network algorithm model, the behavior of real product can be simulated and predicted based on the knowledge of test vehicle database successfully. With the aid of multiple layer erosion/ dishing Neural-Network algorithm model prediction, the potential high risky hot spots can be highlighted at the initial layout design stage, then further shorten the turn-around time of design layout validation.

Biodegradable Polymeric Foams Based on Modified Castor Oil, Styrene, and Isobornyl Methacrylate.

The environmental issues of petroleum-derived polymeric foams have necessitated seeking renewable alternatives. This work aims to prepare renewable free-radically polymerized polymeric foams with the ability to biodegrade. Furthermore, this work attempted to incorporate a bio-based reactive diluent, which has not been reported in the literature. The synthesis of maleated castor oil glycerides was performed with products analyzed by Fourier transform infrared spectrometry using attenuated total reflection (ATR-FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy. Polymeric foams were prepared using maleated castor oil glycerides via free radical copolymerization with styrene and isobornyl methacrylate as reactive diluents. Scanning electron microscopy (SEM) was used to determine anisotropic macrocellular morphology, with log-normal cell diameter distributions. The compressive mechanical and energy absorption properties were investigated; the polymeric foams displayed Young’s modulus up to 26.85 ± 1.07 MPa and strength up to 1.11 ± 0.021 MPa using styrene as the reactive diluent, and Young’s modulus up to 1.38 ± 0.055 MPa and strength up to 0.088 MPa when incorporating isobornyl methacrylate. Furthermore, a thorough analysis of the cellular structure–property relationships was performed, indicating relationships to cell diameter, cell wall thickness and apparent density. The polymeric foams displayed rapid mass loss in an aerobic soil environment with multiple erosion sites revealed by SEM. In conclusion, renewable polymeric foams with excellent compressive properties were achieved using styrene as reactive diluent, but the incorporation of isobornyl methacrylate decreased strength-related properties.

Arc erosion characteristics evolution of Ag/Ti3SiC2 composites during repetitive arc breakdowns in SF6 gaseous medium

AbstractTo disclose the impact of SF6 gaseous medium on Ag/Ti3SiC2 contact materials, arc discharges on the Ag/Ti3SiC2 cathodes were performed 100 times in SF6 gas at 10 kV. After 1, 50, and 100 times of arc discharges, the morphologies of arc‐eroded surfaces were characterized. The changes in breakdown strength with the number of tests were recorded. After 100 times of arc erosion, the composition of the surface was characterized, and the morphologies and compositions of the cross section were measured. In the process of multiple arc breakdowns, the arc erosion position randomly changes. In the later stage of tests, the breakdown strength of Ag/Ti3SiC2 increased. The protrusion on the arc‐eroded surface is the ignition point for the arc, the down of protrusion height and the smooth of protrusion tip were observed after multiple arc discharges, which may result in the increase in breakdown strength. After multiple arc erosion tests, Ag2S was detected on the surface by XPS, and part of silicon elements were dissociated outward from Ti3SiC2. The composition change is inferred to be one of the reasons for the rise of breakdown strength.

Eco-environmental impacts of dams in the Yangtze River Basin, China

Nearly half large dams of China have been built in the Yangtze River Basin (YRB) and the eco-environmental impacts of existing dams remain elusive. Here we present a spatio-temporal approach to measuring the eco-environmental impacts of dams and its long-term changes. We also develop a new metric, the dam eco-environmental effect index (DEEI), that quickly identifies the eco-environmental impacts on dams over 36 years. Underlying the analysis are the revised universal soil loss equation (RUSLE), the generalized boosted regression modeling (GBM), the generalized linear model (GLM), stepwise multiple regression, trend analysis, soil erosion and sediment yield balance equation, and sample entropy used to identify the eco-environmental impacts of dams on yearly timescales. We find that the accumulated negative environmental effects of constructed dams have increased significantly and has led to large-scale hydrophysical and human health risk affecting the Yangtze River Basins downstream (i.e. Jianghan-Lushui-Northeastern Hubei, Dongting Lake District, Yichang-Jianli, and Qingjiang) and reservoir areas (i.e. Wanxian-Miaohe, Miaohe-Huanglingmiao, and Huanglingmiao-Yichang). We also provide observational evidence that dam construction has reduced the complexity of short-term (1–12 months) in runoff and sediment loads. This spatial pattern seems to reflect a filtering effect of the dams on the temporal and spatial patterns of runoff and sediment. Three Gorges Dam (TGD) has a significant impact on the complexity of the runoff and sediment loads in the mainstream of the Yangtze River. This enhanced impact is attributed to the high trapping efficiency of the dam and its associated large reservoir. This assessment may underestimate the cumulative effect of the dam because it does not consider the future effects of the planned dam. Our study provides a quantitative methodology for finding the relative change rate of eco-environmental impact on dams, which is the first step towards addressing the extent, process, and magnitude of the dam-induced effects.

Quantifying Multiple Erosion Events in the Distal Sector of the Northern Alpine Foreland Basin (North-Eastern Switzerland), by Combining Basin Thermal Modelling with Vitrinite Reflectance and Apatite Fission Track Data

This work quantifies the amount of erosion associated with the Cretaceous and Miocene erosional unconformities recognised in the distal part of the Northern Alpine Foreland Basin (NAFB), north-eastern Switzerland. To achieve this goal, the basin thermal modelling approach is applied, calibrated by two different sets of data collected in previous studies: vitrinite reflectance (%Ro) and the temperature estimated from apatite fission tracks (AFT) data modelling. The novelty of this approach is the possibility to constrain the timing and magnitude of multiple erosion events by integrating thermal modelling with thermochronologic data. Combining these two methods allows the erosional events to be separated which would not be possible using only irreversible paleothermometers, such as vitrinite reflectance data. Two scenarios were tested, based on the data of two published thermochronology studies. For the Cretaceous unconformity, similar results are obtained for the two scenarios, both indicating that the deposition and the subsequent complete erosion of Lower Cretaceous deposits, in the order of 500–1300 m, depending on the area, are necessary, in order to attain the temperatures estimated by the thermal history modelling of AFT data. Thus, a depositional hiatus for this period is not likely. For the Miocene-Quaternary unconformity, the magnitude of erosion calculated for the two scenarios differs by 300–1400 m, depending on the AFT data considered. The two scenarios lead to a different evaluation of the subsidence and uplift rate of the study area, thus to a different interpretation of the tectono-stratigraphic evolution of this distal sector of the NAFB.

Head and Neck Manifestations of Multiple Myeloma.

Plasma cell dyscrasia is the term used to describe the disorders characterized by neoplastic proliferations of plasma cells with production of immuno globulins. Of all the plasma cell dyscrasias, multiple myeloma is the commonest and clinically important. Multiple myeloma accounts for 1% of all malignancies and 10-20% of all hematologic malignancies. Mostly the patients present with bone pain, pathological fractures, renal insufficiency or infections. Here we present two cases of multiple myeloma with unusual presentations admitted in the otorhinolaryngology department of a tertiary care center. One 50-yearold male presented with a mass in the left external auditory canal along with left facial palsy and the other a 45yr oldfemale, who presented with painful deglutition, multiple mucosal erosion in oral cavity, throat tightness and left side facial pain. Both cases are examined and evaluated and found to have multiple myeloma. They were referred to the Hematology department for further management.