Effect of antimalarials on clinical outcomes in lupus nephritis.

OBJECTIVES: To evaluate the effect of antimalarial drugs in response to therapy, incidence of LN flares, and progression of kidney disease in a large LN cohort. METHODS: We retrospectively studied 424 biopsy-proven LN patients followed for >3 years. We obtained demographic, clinical, laboratory, histopathological, and treatment variables. Antimalarial use was approached as 1) users versus no users, 2) according to prevalent vs incident use regarding the LN flare, and 3) according to the type of antimalarial. All outcomes were evaluated by time-to-event analyses. Adjusted hazard ratios were obtained by Cox regression. RESULTS: The cohort included 424 patients, median age of 29 years (IQR 23-37), 96% female, with a median eGFR of 81 ml/min/1.73m2 (IQR 48-118) and proteinuria of 3.4 g/g (IQR 1.9-5.5). Antimalarial use was associated with higher complete response (aHR 1.57, 1.08-2.27), lower incidence of kidney flares (aHR 0.63, 0.43-0.92), and lower progression to kidney failure (aHR 0.37, 0.23-0.53). The effect on these outcomes was modified by the presentation eGFR, histological class, and/or concomitant initial immunosuppressor. These protective effects were observed in patients with prevalent or incident use regarding the LN flare and patients using hydroxychloroquine. The incidence of toxic retinopathy was 1.7%, 5.7%, and 8.8% by 3-, 5-, and 7 years of continued antimalarial use. CONCLUSION: The use of antimalarial drugs is associated with increased response to therapy, lower incidence of kidney flares, and lower progression to kidney failure in LN patients. Conversely, this population is at high risk of toxic maculopathy, and yearly ophthalmologic examination is recommended.

The influence of repeated flares in response to therapy and prognosis in lupus nephritis.

BACKGROUND: Repeated renal flares in lupus nephritis (LN) have been associated with worse long-term kidney function. This study aimed to assess the impact of repeated LN flares in response to therapy, kidney and patient prognosis. METHODS: All patients from a biopsy-proven LN cohort between 2008 and 2018 were segregated into three groups according to the number of LN flares when they entered our cohort: first LN flare, second LN flare or third LN flare. The following outcomes were evaluated by unadjusted and adjusted time-to-event analyses: complete and partial response, disease relapses, progression to decline of 30% of the estimated glomerular filtration rate (eGFR), doubling of serum creatinine, end-stage kidney disease and patient survival. RESULTS: A total of 441 patients were included: 257 (58%) in their first LN flare, 102 (23%) in their second LN flare and 82 (19%) in their third LN flare. There were significant differences in LN flare presentation in age, eGFR, serum albumin, pyuria and hematuria among groups. The National Institutes of Health chronicity indices and the percentage of patients with vascular lesions were higher in groups at progressive LN flares. In the adjusted analyses, complete and partial response rates decreased, as well as kidney and patient survival, at a progressive number of LN flares. No differences in the dynamic course of all surveillance laboratory parameters were observed in the first year after initial therapy among LN flare groups. CONCLUSIONS: A progressive number of LN flares is associated with a lower response to therapy and an adverse prognosis for kidney function and patient survival.

Linking Load, Fuel, and Emission Controls to Photochemical Production of Secondary Organic Aerosol from a Diesel Engine.

Diesel engines are important sources of fine particle pollution in urban environments, but their contribution to the atmospheric formation of secondary organic aerosol (SOA) is not well constrained. We investigated direct emissions of primary organic aerosol (POA) and photochemical production of SOA from a diesel engine using an oxidation flow reactor (OFR). In less than a day of simulated atmospheric aging, SOA production exceeded POA emissions by an order of magnitude or more. Efficient combustion at higher engine loads coupled to the removal of SOA precursors and particle emissions by aftertreatment systems reduced POA emission factors by an order of magnitude and SOA production factors by factors of 2-10. The only exception was that the retrofitted aftertreatment did not reduce SOA production at idle loads where exhaust temperatures were low enough to limit removal of SOA precursors in the oxidation catalyst. Use of biodiesel resulted in nearly identical POA and SOA compared to diesel. The effective SOA yield of diesel exhaust was similar to that of unburned diesel fuel. While OFRs can help study the multiday evolution, at low particle concentrations OFRs may not allow for complete gas/particle partitioning and bias the potential of precursors to form SOA.

Interaction of the Agrobacterium tumefaciens virulence protein VirD2 with histones.

Agrobacterium tumefaciens is a Gram-negative soil bacterium that genetically transforms plants and, under laboratory conditions, also transforms non-plant organisms, such as fungi and yeasts. During the transformation process a piece of ssDNA (T-strand) is transferred into the host cells via a type IV secretion system. The VirD2 relaxase protein, which is covalently attached at the 5' end of the T-strand through Tyr29, mediates nuclear entry as it contains a nuclear localization sequence. How the T-strand reaches the chromatin and becomes integrated in the chromosomal DNA is still far from clear. Here, we investigated whether VirD2 binds to histone proteins in the yeast Saccharomyces cerevisiae. Using immobilized GFP-VirD2 and in vitro synthesized His6-tagged S. cerevisiae proteins, interactions between VirD2 and the histones H2A, H2B, H3 and H4 were revealed. In vivo, these interactions were confirmed by bimolecular fluorescence complementation experiments. After co-cultivation of Agrobacterium strains expressing VirD2 tagged with a fragment of the yellow fluorescent protein analogue Venus with yeast strains expressing histone H2A or H2B tagged with the complementary part of Venus, fluorescence was detected in dot-shaped structures in the recipient yeast cells. The results indicated that VirD2 was transferred from Agrobacterium to yeast cells and that it interacted with histones in the host cell, and thus may help direct the T-DNA (transferred DNA) to the chromatin as a prelude to integration into the host chromosomal DNA.

Exostosin-1/exostosin-2 expression and favorable kidney outcomes in lupus nephritis: a retrospective cohort study.

INTRODUCTION/OBJECTIVES: The heterodimer exostosin-1/exostosin-2 (EXO-1/2) is a novel antigen observed in membranous nephropathy associated with systemic lupus erythematosus. This study aimed to evaluate the association between EXO-1/2 positivity in kidney biopsy and kidney outcomes. METHODS: The kidney biopsy tissue from 50 class 5 lupus nephritis (LN) and 55 mixed class 3/4 + 5 LN patients was stained for EXO-1/2. Baseline clinical and histological characteristics were compared between EXO-1/2 positive and EXO-1/2 negative patients. Time-to-event analyses were performed to compare rates of response to therapy, kidney flares, and progression to a 40% decline of the glomerular filtration rate (eGFR), doubling of serum creatinine, and kidney failure. RESULTS: Fourteen out of 50 (28%) of class 5 and 5 out of 55 (9%) of mixed class 3/4 + 5 LN stained positive for EXO-1/2. Patients with class 5 LN and EXO-1/2 positive stain were younger, with better kidney function at presentation, and lower scarring in the kidney biopsy analysis. Over a median follow-up of 100 months, patients with positive EXO-1/2 staining had significantly lower rates of progression in the full cohort. When analyzed separately in class 5 and mixed class LN subgroups, there were significantly lower rates of progression to a 40% decline of the eGFR and non-statistically significant trends for doubling of serum creatinine and kidney failure. CONCLUSION: EXO-1/2 is a novel antigen detected in class 5 LN and associated with a good prognosis of kidney function. The incorporation of EXO-1/2 staining in clinical practice can potentially modify the management of LN due to its prognostic implications. Key Points • Exostosin-1/exostosin-2 antigen has been found in cases of membranous nephropathy associated with autoimmune diseases such as systemic lupus erythematosus. • Exostosin-1/exostosin-2 staining in the kidney biopsy of class 5 or mixed class 3/4 + 5 lupus nephritis is associated with a good long-term prognosis of kidney function. • The incorporation of exostosin-1/exostosin-2 staining into clinical practice can potentially modify management due to its prognostic implications.

RECORD, a high-throughput, customizable system that unveils behavioral strategies leveraged by rodents during foraging-like decision-making.

Translational studies benefit from experimental designs where laboratory organisms use human-relevant behaviors. One such behavior is decision-making, however studying complex decision-making in rodents is labor-intensive and typically restricted to two levels of cost/reward. We design a fully automated, inexpensive, high-throughput framework to study decision-making across multiple levels of rewards and costs: the REward-COst in Rodent Decision-making (RECORD) system. RECORD integrates three components: 1) 3D-printed arenas, 2) custom electronic hardware, and 3) software. We validated four behavioral protocols without employing any food or water restriction, highlighting the versatility of our system. RECORD data exposes heterogeneity in decision-making both within and across individuals that is quantifiably constrained. Using oxycodone self-administration and alcohol-consumption as test cases, we reveal how analytic approaches that incorporate behavioral heterogeneity are sensitive to detecting perturbations in decision-making. RECORD is a powerful approach to studying decision-making in rodents, with features that facilitate translational studies of decision-making in psychiatric disorders.

The first-year course of urine MCP-1 and its association with response to treatment and long-term kidney prognosis in lupus nephritis.

OBJECTIVES: The present study aims to assess the course of uMCP-1 and its association with response to therapy and long-term kidney function in a prospective cohort of adults who received a kidney biopsy for suspicion of active lupus nephritis (LN). METHODS: Subjects were segregated into a histologically active LN group and a histologically chronic LN group. Both groups were followed for > = 36 months and urine were collected at flare, 3, 6, and 12 months of follow-up. The association between the course of uMCP-1, response to treatment, and progression to 30% loss of the eGFR was evaluated by linear mixed models for repeated measures. RESULTS: A kidney biopsy was performed on 125 subjects. In 114, the report was consistent with histologically active LN; in 11, with histologically chronic LN. Urine MCP-1 levels were significantly higher in the active LN than in the chronic LN group. Urine MCP-1 levels correlated with the histological findings of cellular crescents, endocapillary hypercellularity, interstitial inflammation, glomerular sclerosis, interstitial fibrosis, and tubular atrophy. The mean estimates of uMCP-1 at flare were higher in the non-response group than in the complete response group, and decreased in the complete/partial response groups by the third month, while they remained elevated in the non-response group. The mean estimates for uMCP-1 were higher at LN flare and remained elevated in patients who progressed to loss of 30% of the eGFR, while they decreased in patients with stable kidney function. CONCLUSION: The first-year course of uMCP-1 is associated with response to therapy and kidney survival in LN. Key Points •Urine MCP-1 levels differentiate histologically-active lupus nephritis from histologically-chronic lupus nephritis •Urine MCP-1 levels decrease by 3 months of therapy in subjects with a favorable response whose kidney function remains stable long-term •Urine MCP-1 levels remain elevated during the first year of therapy in subjects the will later lose kidney function.

Predictors of treatment outcomes in lupus nephritis with severe acute kidney injury and requirement of dialytic support.

INTRODUCTION/OBJECTIVES: Acute kidney injury (AKI) with the requirement of kidney replacement therapy (KRT) portends a poor prognosis for kidney function in lupus nephritis (LN). This study evaluated the kidney function recovery rates, the rates of reinitiation of KRT, and factors associated with these outcomes in LN. METHOD: All consecutive patients hospitalized for LN with KRT requirement between 2000 and 2020 were included. Their clinical and histopathologic characteristics were retrospectively registered. The outcomes and associated factors were evaluated by multivariable Cox regression analysis. RESULTS: Among 140 patients, 75 (54%) recovered kidney function, with recovery rates of 50.9% and 54.2% by 6 and 12 months of therapy. The factors associated with a lower probability of recovery included a previous history of LN flares, worse eGFR and higher proteinuria at presentation, immunosuppression with azathioprine, and hospitalizations within 6 months of therapy initiation. There was no difference in the kidney function recovery rates between mycophenolate and cyclophosphamide treatment schemes. Out of 75 patients who recovered kidney function, 37 (49%) reinitiated KRT, with KRT reinitiation rates of 27.2% and 46.5% by 3 and 5 years. Seventy-three (52%) patients had at least one hospitalization within 6 months of initial therapy, 52 (72%) of them secondary to infectious events. CONCLUSIONS: Approximately 50% of patients with LN and KRT requirement recover kidney function within 6 months. The risk-to-benefit ratio decisions may be aided by clinical and histological factors. These patients require close follow-up as ≈50% of those who recover kidney function will reinitiate dialysis in the long term. Key Points • Approximately 50% of patients with severe acute lupus nephritis with the need for kidney replacement therapy requirement recover their kidney function. • The factors associated with a lower probability of recovery of kidney function include a previous history of LN flares, worse eGFR and higher proteinuria at presentation, immunosuppression with azathioprine, and hospitalizations within 6 months of therapy initiation. • Patients who recover kidney function will require close follow-up as around 50% of them will eventually reinitiate kidney replacement therapy.

Emulsion Polymerization Using an Amphiphilic Oligoether Ionic Liquid as a Surfactant.

We investigate the use of an ionic liquid (IL) as a surfactant in emulsion polymerization (EP) reactions. ILs have been proposed as surfactants for micellar dispersions, emulsions, micro-emulsions and suspensions. Thus, it is important to acquire knowledge of the application of ILs in heterogeneous polymerizations. We selected the amphiphile cationic oligoether IoLiLyte C1EG™ as an IL for this purpose and compared its performance to that of the conventional surfactant dodecyl trimethyl ammonium bromide (DTAB) in the EP of methyl methacrylate and styrene. After we found the proper concentration range of the IL, this amphiphile showed similar polymerization rates to those observed with DTAB for both monomers. The evolution of monomer conversion and the final average diameter of formed polymeric particles were similar for both evaluated surfactants, demonstrating their capability to stabilize the EPs of the investigated monomers. We simulated the evolution of monomer conversion and particle size using a conventional model for emulsion polymerization, which showed good agreement with the experimental data, suggesting that the EP with this IL follows Smith-Ewart kinetics.

Validation of a renal risk score in a cohort of ANCA-associated vasculitis patients with severe kidney damage.

OBJECTIVE: To validate the renal risk score in a cohort of patients with advanced kidney damage. METHODS: A total of 72 patients with biopsy-proven ANCA glomerulonephritis with >12 months of follow-up were studied. The renal risk score was calculated and evaluated by survival analysis for time of renal survival. Cohort-specific clinical, histopathologic, and post-treatment factors associated with renal survival were determined by Cox regression analysis. RESULTS: Kidney biopsies were classified as focal, crescentic, mixed, and sclerotic classes in 6 (8%), 4 (6%), 25 (35%), and 37 (51%) patients, respectively. The 1-, 3-, and 5-year renal survival rates were 79%, 73%, and 68%, respectively. Patients were segregated by the risk score in low- (18%), medium- (47%), and high-risk (35%) groups. Patients in the low-risk group had 36-, 60-, and 84-month renal survival of 100%; those in the medium risk 85% (95% CI 72-92), 81% (95% CI 66-95), and 76% (95% CI 60-92), respectively; and those in the high risk 37% (95% CI 17-57), 26% (95% CI 7-45), and 18% (95% CI 1-36), respectively. Six (43%) of the 14 patients in the high-risk group recovered renal function after the initial episode, and 2 (14%) remained dialysis-free. Other parameters associated with renal survival included age, proteinuria, general symptoms, cellular crescents, glomerulosclerosis, tubulointerstitial lesions, best post-treatment eGFR, and renal relapses. CONCLUSIONS: We validated the renal risk score as a prognostic tool in a cohort with predominantly mixed and sclerotic histologic categories. Since patients in the high-risk group still benefited from immunosuppressive therapy, this score should be used in conjunction with other predictive parameters to aid therapeutic decisions.Key Points• The ANCA renal risk score is validated in a cohort with advanced kidney damage.• Patients in the high-risk group still benefited from immunosuppressive therapy.• Parameters not included in the risk score are associated with renal survival and may be useful.

Correction to: Validation of a renal risk score in a cohort of ANCA-associated vasculitis patients with severe kidney damage.

The footnote of Figure 2 in the published original version of the above article went missing and the correct figure is presented in this article.

Urinary 1-hydroxypyrene and PAH exposure in 4-year-old Spanish children.

AIMS: Exposure to polycyclic aromatic hydrocarbons (PAH), among the main compounds present in polluted urban air, is of concern for children's health. Childhood exposure to PAH was assessed by urinary monitoring of 1-hydroxypyrene (1-OHP), a pyrene metabolite, investigating its association with exposure to air pollution and other factors related to PAH in air. METHODS: A group of 174 4-year-old children were recruited and a questionnaire on their indoor and outdoor residential environment was completed by parents. At the same time, environmental measurements of traffic-related air pollution (NO2) were carried out. A urine sample was collected from each child in order to analyze 1-OHP using HPLC with fluorescence detection, correcting for creatinine concentrations. Non-parametric tests and regression analyses were used to identify environmental factors that influence 1-OHP excretion. RESULTS: Mean urinary 1-OHP concentration was 0.061 micromol/mol creatinine, ranging from 0.004 to 0.314 micromol/mol. Non-parametric tests and regression analysis showed positive and significant associations (P

Factors influencing the rate of beach sand wear: Activation layer thickness and sediment durability.

The construction of harbours on the coast and/or dams in river courses prevents the contribution of sediments from rivers and ravines to the coastline and interferes with natural coastal dynamics. In the present study, the main objective is to provide information to the coastal engineer to predict and quantify the wear and tear of sand for artificial beach nourishment, as well as the durability of the intervention. For this purpose: (i) the amount of sample used in laboratory tests is related to the actual activation layer due to waves, and (ii) the material durability (aging) is demonstrated. Sands belonging to 9 beaches in the province of Alicante (Spain) were tested and studied, with different sample quantities (60, 75, 100, 120 and 150 g), the granulometry, calcimetry and wear (using the accelerated particle wear test, APW). The results showed that (generally) the greater the amount of sample used (activation layer), the greater the mass loss (reduction to size <0.063 mm) during the first cycle of the wear test. This may be due to the fact that the greater the amount of material in suspension (as a consequence of greater energy for the same volume of water), the greater the possibility of collision between particles, and therefore, greater particle wear and greater erosion on the beach. In addition, when the same material was subjected to new wear test cycles, that is, without the addition of new material (as is currently happening on the coasts), the durability of the same was compromised up to its wear limit. Particle wear reduces the median sediment size, which encourages movement towards the off-shore zone. Therefore, the wave energy, the material durability and the median sand diameter are elements to be taken into account in a beach nourishment.

Tricuspid valve-in-valve procedure: a step-by-step guideline.

Objective: The aim of this study was to present a valve-in-valve (ViV) case and a step-by-step guideline on how to perform this procedure. Methods: A 51-year-old female with a history of rheumatic heart disease and tricuspid valve replacement presented functional class deterioration, a transesophageal echocardiogram (TEE) revealed prosthetic dysfunction due to thrombosis; therefore, a valvular replacement with a 27 mm bioprosthesis (Carpentier-Edwards Perimount) was performed without complication. 3 years after the procedure, the patients presented functional class deterioration (NYHA-III) with tricuspid dysfunction by TEE and the heart team decided to perform a transcatheter tricuspid ViV replacement.

Objetivo: El objetivo de este artículo es presentar un caso clínico de un paciente en el cual se realizó el procedimiento valve-in-valve (ViV) en la válvula tricúspide junto con una guía de cómo llevar a cabo este procedimiento paso a paso. Metodología: Paciente femenino de 51 años de edad con antecedente de Cardiopatía Reumática presenta deterioro en clase funcional encontrándose por ecocardiografía transesofágica (ETE) disfunción de válvula protésica tricúspide secundario a trombosis, se realiza recambio valvular con prótesis biológica 27 mm (Carpentier Edwards Perimount) sin complicación. 3 años después, presenta deterioro de la clase funcional (NYHA-III) y se evidencia en ETE disfunción protésica tricúspide por lo cual se decide realizar un reemplazo ViV tricúspide transcatéter.

Tricuspid valve-in-valve procedure: a step-by-step guideline.

Objective: The aim of this study was to present a valve-in-valve (ViV) case and a step-by-step guideline on how to perform this procedure. Methods: A 51-year-old female with a history of rheumatic heart disease and tricuspid valve replacement presented functional class deterioration, a transesophageal echocardiogram (TEE) revealed prosthetic dysfunction due to thrombosis; therefore, a valvular replacement with a 27 mm bioprosthesis (Carpentier-Edwards Perimount) was performed without complication. 3 years after the procedure, the patients presented functional class deterioration (NYHA-III) with tricuspid dysfunction by TEE and the heart team decided to perform a transcatheter tricuspid ViV replacement.

Objetivo: El objetivo de este artículo es presentar un caso clínico de un paciente en el cual se realizó el procedimiento valve-in-valve (ViV) en la válvula tricúspide junto con una guía de cómo llevar a cabo este procedimiento paso a paso. Metodología: Paciente femenino de 51 años de edad con antecedente de Cardiopatía Reumática presenta deterioro en clase funcional encontrándose por ecocardiografía transesofágica (ETE) disfunción de válvula protésica tricúspide secundario a trombosis, se realiza recambio valvular con prótesis biológica 27 mm (Carpentier Edwards Perimount) sin complicación. 3 años después, presenta deterioro de la clase funcional (NYHA-III) y se evidencia en ETE disfunción protésica tricúspide por lo cual se decide realizar un reemplazo ViV tricúspide transcatéter.

Study of the evolution of gravel beaches nourished with sand.

Coastal erosion is a worldwide problem, so accurate knowledge of the factors involved in the shoreline evolution is of great importance. This study analysed three gravel beaches that were nourished with sand from the same source. However, the evolution of their shoreline was different in each case. For its analysis, different factors were studied such as the shoreline and cross-shore profile evolution, the maritime climate, sedimentology and mineralogy. From the results, it should be noted that Centro beach is the most stable with a loss of surface after the first regeneration of 12.8%, while Carrer de mar is the most instable with a loss of 20.9%. The Posidonia oceanica meadow is one of the factors that make Centro beach the most stable despite being the one that receives the most wave energy. Another factor is its mineralogy and more specifically the composition of the particles that form the sample. Thus, it is observed how the cracking or the formation of particles by different minerals with a fragile union, are factors that make the beaches behave differently against erosion. For this reason, it is concluded that in order for the shoreline to be as stable as possible over time, a previous study of the sediment to be used for nourishment is necessary, as well as its possible effect on the ecosystem, since the future shoreline evolution will depend on it.

Mineralogy and morphology of sand: Key parameters in the durability for its use in artificial beach nourishment.

Sand is the third most consumed material in the world, although it is a very scarce material. An exhaustive knowledge of sand and its behaviour against the waves is important for selecting the most suitable material to avoid shoreline erosion. To this end, a pattern of behaviour against accelerated wear test has been sought for 26 sand samples with different characteristics and origins (natural, dredged and quarried), with a focus on their mineralogy as well as a comparison of beach evolution carried out by other authors. Several techniques have been applied for characterization: granulometry, calcimetry, XRD and SEM. The results show that the different degrees of sand grain wear are not only due to their size and mineralogy, but also to the morphology of the particles.

Causes of the different behaviour of the shoreline on beaches with similar characteristics. Study case of the San Juan and Guardamar del Segura beaches, Spain.

Storms can alter the beach shape, relocating large volumes of sediments and generating drastic changes in the coastline. In the last 60years, beaches shoreline behaviour has been different even though the energy of the waves was similar. Therefore, it is necessary to understand the factors that affect the sandy coasts for better future management. In this research, two beaches, with different erosion rate, located in the southeast of Spain (separated by only 40km of distance) have been studied. The beaches: i) have similar orientations, ii) are open to waves with similar sand lengths of 9.8km and 6.6km, and iii) have similar median sediment size (D50). For its study, shoreline evolution has been analysed from 1956 to 2017. From the results obtained, it can be seen that: i) Between 1992 and 2017, San Juan just lost 3% of its surface, while in the previous period (1956-1990) it was 50%, and ii) Guardamar surface lost in 1992-2017 was 18%, and in the previous period it was 14%. For the analysis of the agents involved in both beaches, cross-shore profiles (volume), marine climate, biocenosis and sedimentology studies were carried out. The results showed that the energy on both beaches was very similar. The biocenosis had not changed and, however, the morphology of Guardamar seabed had increased to 1m deep in some places, which had caused part of the beach berm erosion. Furthermore, important differences were found from the sedimentological study, concluding that the content of calcites and the degree of homogeneity of the particles are the real factors that caused these two beaches to behave differently against erosion.

The effects of sediment used in beach nourishment: Study case El Portet de Moraira beach.

Actions taken to prevent or reduce coastal erosion often do not have the desired effect, leading to major problems instead of solving the original one. This research focuses on why a nourished beach- with borrowed sand and 0.05% of particles <0.063 mm- causes the presence of suspended particles that are observed by beach users as turbidity. This means that the colour of the water was not its characteristic blue, even with calm wave conditions. This research involved a shoreline evolution analysis and a sedimentological study of the sand from 1977 to 2017. The results show that the turbidity episodes that occurred after the beach fill of May 2017 do not coincide with major storms that affected the beach. Furthermore, prior to this beach nourishment, even after the most important storms turbidity was not so pronounced. However, when the pre-nourishment and post-nourishment sediment are compared and analysed in detail, by studying the microstructure and morphology of the sand particles, their composition and morphology were observed to be completely different. These differences are also reflected in the accelerated particle weathering test, with the post-nourishment particles showing greater dissolution of carbonates. From its mineralogy, the post-nourishment material presents a smaller proportion of quartz in its composition and a significant amount of particles (9.6%) formed by clusters of Calcium and Silicon. The separation of this mineralogical composition produced by waves explains the formation of particles measuring <0.063 mm, a fact that has also been confirmed by the accelerated particle weathering test. This is, therefore, the cause of turbidity in the swash zone of the beach.