Hydrochemical characterization, spatial distribution, and geochemical controls on arsenic and boron in waters from arid Arica and Parinacota, northern Chile

The livelihood of inhabitants from rural agricultural valleys in the arid Arica and Parinacota Region, northernmost Chile, strongly depends on water from high altitude rainfall and runoff to lower elevation areas. However, elevated arsenic, boron, and other potentially harmful elements compromise water quality, especially in rural areas. Samples (n = 90) of surface, underground, cold, geothermal springs, and treated and raw tap water were studied to assess water quality and to determine the main geochemical controls on water composition, origin, and geochemical evolution along dominant flowpaths. Water from major river basins across the region (Lluta, San Jose, Codpa-Chaca, Camarones and Altiplanicas) were collected for hydrogeochemical analysis of a suite of major and trace elements, δD and δ¹⁸O. Our new dataset was supplemented by hydrochemical data (n > 1500 data points) from secondary sources. Results show that 72% of the collected samples had As >10 μg/L (WHO drinking water provisional guideline) and affected 44% of the studied waters used for drinking (n = 32). Based on Chilean irrigation guidelines, elevated salinity (EC > 0.75 mS/cm) affected 80% of sampled waters, which were also impacted by high B (89% > 0.75 mg/L), and As (31% > 50 μg/L). Water composition was strongly controlled by geothermal water and freshwater mixing in high altitude areas. Magnitude and fate of As and B concentration was determined by the geothermal input type. Highest As (~21 mg/L) was associated with circum-neutral Na-Cl waters in Camarones basin, while lower As (~5 mg/L) with acid SO₄ waters in Lluta basin. Additionally, evaporative concentration and sediment-water interactions were shown to control the level of As in surface and groundwaters downstream. This works provides a comprehensive analysis and a conceptual model of geochemical controls on regional water compositions, contributing to better understanding the geochemical processes underpinning the water quality challenges in northern Chile.

Chemical composition of Chilean bottled waters: Anomalous values and possible effects on human health

The Chilean bottled water market has experienced continuous growth since 2000, surpassing 500 million liters sold in 2015. Generally, consumers tend to associate the consumption of bottled water with a healthy lifestyle, but current Chilean law does not require the product to be labelled with the chemical composition, thus preventing consumers from making informed choices. Our study focuses on determining the water quality of ten brands of bottled water available for sale in Santiago, Chile. All of the analyzed water was not carbonated and in plastic containers in the 1.5 L size when available and the closest size to this when not available. Thirty-two chemical elements were analyzed, including minor and trace elements, and the data have been evaluated with respect to the limits established by Chilean and international regulatory agencies. Our results indicate that the quality of the analyzed water generally complies with Chilean law for bottled water. However, 30% of the analyzed samples exceed the values of arsenic (As) permitted by Chilean drinking water regulations, the World Health Organization and the United States Environmental Protection Agency. In 40% of the samples, the NO₃ content is higher than groundwater values suggesting that the source of the bottled water is superficial. The purified bottled water brands contain minimal amounts of dissolved elements but do not comply with all of the parameters (e.g., pH) established by Chilean drinking water regulations. Our study highlights that there is an inconsistency between the Chilean norms that regulate bottled water and those that regulate drinking water. Some of the analyzed bottled waters do not comply with the drinking water regulations and paradoxically these brands should not be consumed by humans. However, risk assessment calculations for As ingestion show that the consumption of 1 L/day of bottled water does not pose a risk for human health.

A biomechanical study of headless compression screws versus a locking plate in radial head fracture fixation

HYPOTHESIS

Fixation of a 3-part radial head fracture with cannulated compression screws will show equivalent stiffness to a locking plate under axial load. Debate exists regarding the management of Mason type III fractures, with many believing that open reduction and internal fixation provides advantages over other options. By virtue of their subarticular placement, screw fixation is less likely to cause impingement compared with plate fixation, which can result in loss of rotation and requirement for hardware removal. Insufficient fixation stability can lead to nonunions, necrosis of the radial head, pain, and instability. We tested the mechanical stability of fixation of simulated radial head fractures using headless compression screws compared with standard plate construct.

METHODS

Standardized test constructs were created with repeatable osteotomy cuts and hardware placement on each Synbone model (Synbone AG, Malans, Switzerland). We presectioned 22 proximal radius Synbone models to simulate a 3-part radial head fracture. The models were fixed using a radial head locking plate or headless compression screws in a tripod construct. The constructs were potted into a compression test jig using 2-part epoxy resin. Compression testing was performed using a 30-kN Instron Universal machine (Instron, Norwood, MA, USA). The compression tool was spherical, representing the surface of the capitellum.

RESULTS

There was no significant difference between the stiffness of the Synbone constructs under axial load.

CONCLUSION

There was no significant difference between fixation stiffness of a 3-part radial head fracture with headless compression screws in a tripod structure vs. a locking plate in Synbone. Further study is required to allow clinical application.

Modelling and testing of a wave energy converter based on dielectric elastomer generators

This paper introduces the analysis and design of a wave energy converter (WEC) that is equipped with a novel kind of electrostatic power take-off system, known as dielectric elastomer generator (DEG). We propose a modelling approach which relies on the combination of nonlinear potential-flow hydrodynamics and electro-hyperelastic theory. Such a model makes it possible to predict the system response in operational conditions, and thus it is employed to design and evaluate a DEG-based WEC that features an effective dynamic response. The model is validated through the design and test of a small-scale prototype, whose dynamics is tuned with waves at tank-scale using a set of scaling rules for the DEG dimensions introduced here in order to comply with Froude similarity laws. Wave-tank tests are conducted in regular and irregular waves with a functional DEG system that is controlled using a realistic prediction-free strategy. Remarkable average performance in realistically scaled sea states has been recorded during experiments, with peaks of power output of up to 3.8 W, corresponding to hundreds of kilowatts at full-scale. The obtained results demonstrated the concrete possibility of designing DEG-based WEC devices that are conceived for large-scale electrical energy production.

Pregnancy in a woman with recurrent immunoglobulin a nephropathy: A case report

Immunoglobulin A nephropathy (IgAN) is the most common form of primary glomerulonephritis and is increasingly encountered in pregnancy. The obstetric and renal outcomes of pregnancy are controversial, however. Women with IgAN are at higher risk of hypertension, preeclampsia and foetal loss; the prognosis is worse for those who have advanced chronic kidney disease and proteinuria. Here we report the case of a 32-year-old nulliparous woman with chronic hypertension who conceived during an active phase of her IgAN, which had been diagnosed 8 years earlier. Antihypertensive therapies and a low-protein diet were key to her reaching 34 weeks' gestation with acceptable kidney function. Rupture of membranes occurred at 34 weeks 3 days' gestation and a healthy boy was delivered the next day. This report aims to provide clinicians with useful information for the management of patients with IgAN during pregnancy.

Osteosynthesis for clavicle fractures: How close are we to penetration of neurovascular structures?

INTRODUCTION

Risks associated with drill plunging are well recognised in clavicle osteosynthesis. To date no studies have described plunge depth associated with clavicle osteosynthesis.

PRIMARY AIM

To determine whether plunge depth associated with clavicle osteosynthesis is great enough to penetrate neurovascular structures and whether surgical experience reduces the risk of neurovascular injury METHOD: Cadaveric clavicles were pressed into spongy phenolic foam to allow measurement of drill bit penetration beyond the far cortex (plunge depth). 15 surgeons grouped according to experience were asked to drill a single hole in the medial, middle and lateral clavicle in 2 specimens each. Each surgeon used fully a charged standard Stryker drill with a new 2.6mm drill bit and guide. Plunge depths were measured in 0.5mm increments. Depth measurements were compared amongst groups and to previously documented distances to neurovascular structures as outlined by Robinson et al. Kruskal-Wallis test was used for overall comparison and Mann-Whitney U test was used for comparing the groups individually.

RESULTS

Mean plunge depth across all groups was 3.4mm, (0.5-6.5), 4.0mm (1mm-8.5mm) and 4.0mm (0.5mm-15mm) in the medial, middle and lateral clavicle. Plunge depths were greater than previously documented distances to the subclavian vein at the medial clavicle on nine occasions. Plunge depths in the middle and lateral clavicle were well within the previously documented distances from neurovascular structures. There was no correlation between level of experience and median plunge depth (p=0.18). However, inexperienced surgeons plunged 1mm greater than intermediate and experienced surgeons (p=0.026). There was one significant outlier; a 15mm plunge depth by an inexperienced surgeon in the lateral clavicle.

CONCLUSION

Clavicle osteosynthesis has a relatively high risk of neurovascular injury. Plunge depths through the clavicle often exceed the distance of neurovascular structures, especially in the medial clavicle. A thorough understanding of the anatomy of these neurovascular structures and methods to prevent excessive plunging is important prior to undertaking clavicle osteosynthesis.

Anatomic Variation in Volar Tilt of the Scaphoid and Lunate Facet of the Distal Radius

PURPOSE

The aim of distal radial fracture treatment is to achieve optimal function through the restoration of normal anatomy, including volar tilt. The accuracy of assessing volar tilt on standard lateral radiographs compared with anatomic tilt lateral (ATL) radiographs is uncertain. This study aimed to investigate the anatomy of the articular surface of the distal radius, in particular measuring the angle between the dorsal and volar rims at several points from radial to ulnar, to ascertain whether volar tilt is uniform between the scaphoid and lunate facet and to explore consistency between standard lateral and ATL views.

METHODS

We studied 38 dry cadaveric specimens of radii. The distal articular surface of each specimen was marked at 5 intervals and placed in a customized jig. A 1.5-mm stylus was placed at each marker to represent the articular surface angle, and was photographed in standard lateral and ATL projections. An on-screen protractor was used to measure each angle from the digital photographs.

RESULTS

The volar tilt measurements at the lunate facet demonstrated a significantly shallower angle than those at the scaphoid facet. The measurements between the standard lateral and ATL were found to have no significant difference.

CONCLUSIONS

Adjusting the projection angle between a simulated standard lateral and ATL view did not significantly change the volar tilt measurements in this anatomic study. The lunate facet was found to have a significantly shallower volar tilt than the scaphoid facet. Variance in radiographic volar tilt may relate to different anatomic sagittal planes, reflecting the anatomic variation between the scaphoid and lunate facets.

CLINICAL RELEVANCE

A detailed understanding of distal radius anatomy is required by the surgeon for accurate radiologic interpretation and anatomic fracture reduction and fixation.

Effectiveness of the surgical torque limiter: a model comparing drill- and hand-based screw insertion into locking plates

Background

The objective of this study is to analyse the effectiveness of the surgical torque limiter during operative use. The study also investigates the potential differences in torque between hand and drill-based screw insertion into locking plates using a standardised torque limiter.

Methods

Torque for both hand and power screw insertion was measured through a load cell, registering 6.66 points per second. This was performed in a controlled environment using synthetic bone, a locking plate and locking screws to simulate plate fixation. Screws were inserted by hand and by drill with torque values measured.

Results

The surgical torque limiter (1.5 Nm) was effective as the highest recorded reading in the study was 1.409 Nm. Comparatively, there is a statistically significant difference between screw insertion methods. Torque produced for manually driven screw insertion into locking plates was 1.289 Nm (95 % CI 1.269–1.308) with drill-powered screw insertion at 0.740 Nm (95 % CI 0.723–0.757).

Conclusions

The surgical torque limiter proved to be effective as per product specifications. Screws inserted under power produce significantly less torque when compared to manual insertion by hand. This is likely related to the mechanism of the torque limiter when being used at higher speeds for which it was designed. We conclude that screws may be inserted using power to the plate with the addition of a torque limiter. It is recommended that all screws inserted by drill be hand tightened to achieve adequate torque values.

Irreducible Lateral Patellar Dislocation: A Case Report and Literature Review

BACKGROUND

Acute patellar dislocation is a common injury in young people, especially in adolescent females and athletes. Lateral dislocation is the most common form of patellar dislocation and often reduces spontaneously or with simple manipulation and closed reduction. We report a rare circumstance in which the patella was irreducible and required manipulation and closed reduction in the operating room.

CASE REPORT

While dancing, a 32-year-old female was knocked by a fellow dancer on her left knee, and she fell to the nightclub floor. She was unable to stand or bear weight because of the pain, and her knee was in fixed flexion with lateral displacement of the patella. Multiple attempts at closed reduction under sedation failed in the emergency department. Computed tomography (CT) images revealed a medial border patellar fracture and lipohemarthrosis that required closed reduction and manipulation in the operating room. The patient was placed in a Richards splint for follow-up and referred to a physiotherapist for conservative management.

CONCLUSION

This case highlights the fact that some lateral patellar dislocations are irreducible on initial attempts, particularly if a fracture is present or another mechanism of impingement impedes relocation. CT imaging is a valuable diagnostic tool, and manipulation under anesthesia or open reduction in the operating room may be necessary. Our review of the literature further highlights the complexity and potential problems associated with treatment of locked lateral patellar dislocations.

Clinical features and lifestyle of patients with amyotrophic lateral sclerosis in Campania: brief overview of an Italian database

BACKGROUND

Physical activity and occupational exposures appeared to play a relevant role in pathogenesis of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease of unknown origin.

MATERIALS AND METHODS

We aimed to make an overview of the clinical characteristics and lifestyle (occupation and sport) of a population of 395 patients with ALS from Campania, in southern Italy.

RESULTS

ALS onset resulted anticipated of about 11 years in industry workers, whilst the more frequent site of onset among farmers was upper limbs. Compared to non-athletes, athletes, particularly soccer players, showed a 7 years anticipation of ALS onset, with higher mortality after 5 years.

DISCUSSION AND CONCLUSIONS

We suggest that subjects genetically prone to abnormal response to hypoxia during strenuous physical activity or exposed to neurotoxic agents, such as athletes, farmers or industry workers, might present increased risk to develop ALS. Future case-control and follow-up studies on our population should be implemented to deepen the present results.

Somatostatin receptor tissue distribution in lung neuroendocrine tumours: a clinicopathologic and immunohistochemical study of 218 'clinically aggressive' cases

BACKGROUND

The management of pulmonary neuroendocrine tumours (NETs), with special reference to clinically aggressive carcinoids and large-cell neuroendocrine carcinomas (LCNECs), is poorly standardised and data about somatostatin receptor (SSTR) expression or therapeutic guidelines for somatostatin analogue administration are still debated.

MATERIALS AND METHODS

A series of 218 lung NETs [24 metastatic typical carcinoids (TCs), 73 atypical carcinoids (ACs), 60 LCNECs and 61 surgically resected small-cell lung carcinomas] were investigated for SSTR types 2A and 3 tissue distribution using immunohistochemistry, in correlation with clinicopathologic parameters, outcome, scintigraphy and treatment.

RESULTS

SSTRs were heterogeneously distributed with a significant progressive decrease from low- to high-grade forms. SSTR type 2A was strikingly overexpressed in metastatic TCs as compared with ACs and clinically benign TCs. SSTR tissue immunolocalization correlated with octreotide scintigraphy in 20 of 28 cases.

CONCLUSION

The immunohistochemical determination of SSTRs, with special reference to low-grade/intermediate-grade tumours, may assist the clinical approach with somatostatin analogue-based diagnostic and therapeutic procedures in clinically aggressive pulmonary NETs.

Early signs of cardiac involvement in hypertension

BACKGROUND

Whether abnormalities of diastolic function are the earliest cardiac change in hypertension is still a matter for dispute. The aim of this study was to assess whether left ventricular diastolic dysfunction is an early sign of cardiac involvement in hypertension.

METHODS

In 578 young patients with stage I hypertension from the Hypertension and Ambulatory Recording Venetia Study (HARVEST) and 101 normotensive control patients echocardiographic Doppler examination and ambulatory blood pressure monitoring were performed.

RESULTS

Left ventricular mass, wall thickness, and relative wall thickness, adjusted for confounders, were greater in the hypertensive than in the normotensive patients (all P <.0001). After adjustment for confounders, the A-wave peak velocity was higher in the hypertensive patients (51.5 +/- 11.5 vs 43.4 +/- 8 cm/s, P <.001) as were A-wave velocity time integral (5.6 +/- 1.7 vs 4.6 +/- 1.3 cm, P =.01), total area (16.9 +/- 4.4 vs 15.6 +/- 3.1 cm, P =.04), and E-wave peak velocity (69.9 +/- 15.2 vs 67.5 +/- 13.3 cm/s, P =.03). All indexes of diastolic function were similar in the hypertensive subjects subdivided according to whether they had "white-coat" or sustained hypertension. Among the hypertensive subjects, age and heart rate were the strongest predictors of diastolic indexes, whereas ambulatory blood pressure explained only a marginal part of the E/A ratio, A-wave peak velocity, and the first one third total area ratio (P =.04, P =.02, and P =.05, respectively). Left ventricular mass and wall thickness were not associated with any Doppler index. When a clustering of diastolic indexes (E/A wave ratio, deceleration time, first one third of diastole, and peak E-wave-velocity) was used to identify subjects with diastolic dysfunction, no significant differences in either clinic or ambulatory blood pressure were observed between the group with diastolic dysfunction and the group with normal function.

CONCLUSIONS

We conclude that the earliest signs of cardiac involvement in hypertension are left ventricular structural abnormalities. Left ventricular diastolic function is only marginally affected, even when multiple parameters of left ventricular filling are taken into account.