Using Immersive Virtual Reality Distraction to Reduce Fear and Anxiety before Surgery.

Presurgical anxiety is very common and is often treated with sedatives. Minimizing or avoiding sedation reduces the risk of sedation-related adverse events. Reducing sedation can increase early cognitive recovery and reduce time to discharge after surgery. The current case study is the first to explore the use of interactive eye-tracked VR as a nonpharmacologic anxiolytic customized for physically immobilized presurgery patients. Method: A 44-year-old female patient presenting for gallbladder surgery participated. Using a within-subject repeated measures design (treatment order randomized), the participant received no VR during one portion of her preoperative wait and interactive eye-tracked virtual reality during an equivalent portion of time in the presurgery room. After each condition (no VR vs. VR), the participant provided subjective 0-10 ratings and state-trait short form Y anxiety measures of the amount of anxiety and fear she experienced during that condition. Results: As predicted, compared to treatment as usual (no VR), the patient reported having 67% lower presurgical anxiety during VR. She also experienced "strong fear" (8 out of 10) during no VR vs. "no fear" (0 out of 10) during VR. She reported a strong sense of presence during VR and zero nausea. She liked VR, she had fun during VR, and she recommended VR to future patients during pre-op. Interactive VR distraction with eye tracking was an effective nonpharmacologic technique for reducing anticipatory fear and anxiety prior to surgery. The results add to existing evidence that supports the use of VR in perioperative settings. VR technology has recently become affordable and more user friendly, increasing the potential for widespread dissemination into medical practice. Although case studies are scientifically inconclusive by nature, they help identify new directions for future larger, carefully controlled studies. VR sedation is a promising non-drug fear and anxiety management technique meriting further investigation.

PET/Graphene Nanocomposite Fibers Obtained by Dry-Jet Wet-Spinning for Conductive Textiles.

The combination of polyethylene terephthalate (PET), one of the most used polymers in the textile industry, with graphene, one of the most outstanding conductive materials in recent years, represents a promising strategy for the preparation of conductive textiles. This study focuses on the preparation of mechanically stable and conductive polymer textiles and describes the preparation of PET/graphene fibers by the dry-jet wet-spinning method from nanocomposite solutions in trifluoroacetic acid. Nanoindentation results show that the addition of a small amount of graphene (2 wt.%) to the glassy PET fibers produces a significant modulus and hardness enhancement (≈10%) that can be partly attributed to the intrinsic mechanical properties of graphene but also to the promotion of crystallinity. Higher graphene loadings up to 5 wt.% are found to produce additional mechanical improvements up to ≈20% that can be merely attributed to the superior properties of the filler. Moreover, the nanocomposite fibers display an electrical conductivity percolation threshold over 2 wt.% approaching ≈0.2 S/cm for the largest graphene loading. Finally, bending tests on the nanocomposite fibers show that the good electrical conductivity can be preserved under cyclic mechanical loading.

Fabrication of Nylon 6-Montmorillonite Clay Nanocomposites with Enhanced Structural and Mechanical Properties by Solution Compounding.

Melt compounding has been favored by researchers for producing nylon 6/montmorillonite clay nanocomposites. It was reported that high compatibility between the clay and the nylon6 matrix is essential for producing exfoliated and well-dispersed clay particles within the nylon6 matrix. Though solution compounding represents an alternative preparation method, reported research for its use for the preparation of nylon 6/montmorillonite clay is limited. In the present work, solution compounding was used to prepare nylon6/montmorillonite clays and was found to produce exfoliated nylon 6/montmorillonite nanocomposites, for both organically modified clays with known compatibility with nylon 6 (Cloisite 30B) and clays with low/no compatibility with nylon 6 (Cloisite 15A and Na+-MMT), though to a lower extent. Additionally, solution compounding was found to produce the more stable α crystal structure for both blank nylon6 and nylon6/montmorillonite clays. The process was found to enhance the matrix crystallinity of blank nylon6 samples from 36 to 58%. The resulting composites were found to possess comparable mechanical properties to similar composites produced by melt blending.

Barriers and Potential Solutions to Implementing Evidence-Based PTSD Treatment in Military Treatment Facilities.

INTRODUCTION: Prolonged exposure therapy is an effective treatment for posttraumatic stress disorder that is underutilized in health systems, including the military health system. Organizational barriers to prolonged exposure implementation have been hypothesized but not systematically examined. This multisite project sought to identify barriers to increasing the use of prolonged exposure across eight military treatment facilities and describe potential solutions to addressing these barriers. MATERIALS AND METHODS: As part of a larger project to increase the use of prolonged exposure therapy in the military health system, we conducted a needs assessment at eight military treatment facilities. The needs assessment included analysis of clinic administrative data and a series of stakeholder interviews with behavioral health clinic providers, leadership, and support staff. Key barriers were matched with potential solutions using a rubric developed for this project. Identified facilitators, barriers, and potential solutions were summarized in a collaboratively developed implementation plan for increasing prolonged exposure therapy tailored to each site. RESULTS: There was a greater than anticipated consistency in the barriers reported by the sites, despite variation in the size and type of facility. The identified barriers were grouped into four categories: time-related barriers, provider-related barriers, barriers related to patient education and matching patients to providers, and scheduling-related barriers. Potential solutions to each barrier are described. CONCLUSIONS: The findings highlight the numerous organizational-level barriers to implementing evidence-based psychotherapy in the military health system and offer potential solutions that may be helpful in addressing the barriers.

Designing New Sustainable Polyurethane Adhesives: Influence of the Nature and Content of Diels-Alder Adducts on Their Thermoreversible Behavior.

With a view to the development of new sustainable and functional adhesives, two Diels-Alder (DA) adducts are incorporated as a third component into the curing process of solvent-based and solvent-free polyurethanes in this study. The influence of the nature and content of the DA molecules on the retro-DA (rDA) reaction and its reversibility and cyclability is investigated. It is demonstrated that the bonding/debonding properties of the adhesives are mainly controlled by the concentration of the DA adducts, with a minimum thermoreversible bond (TB) content required that depends on the system and the total ratio between all the diols in the formulation. For the solvent-based system, rDA/DA reversibility can be repeated up to ~20 times without deterioration, in contrast to the solvent-free system where a gradual loss in the DA network reconstruction efficiency is observed. Despite this limitation, the solvent-free system presents clear advantages from an environmental point of view. The changes observed in the physical properties of these new thermoreversible adhesives are of great relevance for recycling strategies and, in particular, their potential for separating multilayered film packaging materials in order to recycle the individual polymer films involved.

Tracing COVID-19 Source of Infection Among Health Personnel in a Pediatric Hospital.

Health personnel (HP) have been universally recognized as especially susceptible to COVID-19. In Mexico, our home country, HP has one of the highest death rates from the disease. From the beginning of the SARS-CoV-2 pandemic, an office for initial attention for HP and a call center were established at a COVID-19 national reference pediatric hospital, aimed at early detection of COVID-19 cases and stopping local transmission. The detection and call center implementation and operation, and tracing methodology are described here. A total of 1,042 HP were evaluated, with 221 positive cases identified (7.7% of all HP currently working and 26% of the HP tested). Community contagion was most prevalent (46%), followed by other HP (27%), household (14%), and hospitalized patients (13%). Clusters and contact network analysis are discussed. This is one of the first reports that address the details of the implementation process of contact tracing in a pediatric hospital from the perspective of a hybrid hospital with COVID-19 and non-COVID-19 areas.

Using NdSr isotopes in suspended sediments in the Abrolhos coral-reef (SW Atlantic, Brazil) to assess potential contamination from the 2015 Fundão dam collapse.

The Abrolhos bank is home of the richest coral reef system of the Southwestern Atlantic, where endemic coral species are found. It has been reported that Abrolhos' corals are under intense stress due to increasing of Marine Heat Waves during the last decades. Additionally, anthropic interventions along the adjacent coastal regions are a factor of concern since they contribute to the increase in the sediment load and to organic debris input in the reef domain. In November 2015, the collapse of the Fundão mining tailings dam resulted in the release of approximately 50 million m3 of iron oxide and quartz-rich slurry into the Doce River. Aiming at using a fingerprint of the tailings and to assess the presence of traces of the Fundão dam material from this event on the Abrolhos bank, this work presents new 87Sr/86Sr and 143Nd/144Nd isotope ratios of marine suspended sediment samples collected between 2016 and 2020 from a network of sediment traps throughout the reef and complementary suspended material at sea. In parallel, we monitored meteo-oceanographic parameters and modeled surface marine currents as an attempt to identify the sediment transport between the Doce River mouth and Abrolhos bank. The r isotopes were used as provenance proxies based on the fact that minerals and rocks tend to have specific isotopic signatures reflecting their own geological derivation. In this context, the isotopic ratios of various potential regional sources for the sedimentation in Abrolhos bank were evaluated. Our monitoring and isotopic measurements indicate that Doce River signatures are detected at Abrolhos bank, following the seasonal Doce River discharge at sea. Isotopic signature of Doce River at Abrolhos bank was also observed during the austral winter (July-August) when cold fronts migrate at the Brazilian coast with higher frequency and energy.

Understanding the Reinforcement of Graphene in Poly(Ether Ether Ketone)/Carbon Fibre Laminates.

PEEK appears as an excellent candidate to substitute epoxy resins in carbon fibre laminates for high-performance aeronautical applications. The optimization of the properties and, in particular, of the transition region between the fibres and the matrix appear as a major issue prior to serial production. Graphene, modified with two compatibilizers, has been incorporated in the polymer layer with the purpose of imparting additional functionalities and enhancing the matrix-fibre interaction. It is found that both carbon fibres and modified graphene significantly influence the crystallization behaviour and smaller, and/or more imperfect crystals appear while the degree of crystallinity decreases. Despite this, nanoindentation studies show that the PEEK layer exhibits significant modulus improvements (≈30%) for 5 wt.% of graphene. Most importantly, the study of the local mechanical properties by nanoindentation mapping allows the identification of remarkably high modulus values close to the carbon fibre front. Such a relevant mechanical enhancement can be associated with the accumulation of graphene platelets at the polymer-fibre boundary, as revealed by electron microscopy studies. The results offer a feasible route for interlaminar mechanical improvement based on the higher density of graphene platelets at the fibre front that should promote interfacial interactions. Concerning electrical conductivity, a large anisotropy was found for all laminates, and values in the range ~10-4 S/cm were found for the through-thickness arrangement as a consequence of the good consolidation of the laminates.

Sequential Crystallization and Multicrystalline Morphology in PE-b-PEO-b-PCL-b-PLLA Tetrablock Quarterpolymers.

We investigate for the first time the morphology and crystallization of two novel tetrablock quarterpolymers of polyethylene (PE), poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(l-lactide) (PLLA) with four potentially crystallizable blocks: PE18 7.1 -b-PEO37 15.1 -b-PCL26 10.4 -b-PLLA19 7.6 (Q1) and PE29 9.5 -b-PEO26 8.8 -b-PCL23 7.6 -b-PLLA22 7.3 (Q2) (superscripts give number average molecular weights in kg/mol, and subscripts give the composition in wt %). Their synthesis was performed by a combination of polyhomologation (C1 polymerization) and ring-opening polymerization techniques using a ″catalyst-switch″ strategy, either ″organocatalyst/metal catalyst switch″ (Q1 sample, 96% isotactic tetrads) or ″organocatalyst/organocatalyst switch″ (Q2 sample, 84% isotactic tetrads). Their corresponding precursors-triblock terpolymers PE-b-PEO-b-PCL, diblock copolymers PE-b-PEO, and PE homopolymers-were also studied. Cooling and heating rates from the melt at 20 °C/min were employed for most experiments: differential scanning calorimetry (DSC), polarized light optical microscopy (PLOM), in situ small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS), and atomic force microscopy (AFM). The direct comparison of the results obtained with these different techniques allows the precise identification of the crystallization sequence of the blocks upon cooling from the melt. SAXS indicated that Q1 is melt miscible, while Q2 is weakly segregated in the melt but breaks out during crystallization. According to WAXS and DSC results, the blocks follow a sequence as they crystallize: PLLA first, then PE, then PCL, and finally PEO in the case of the Q1 quarterpolymer; in Q2, the PLLA block is not able to crystallize due to its low isotacticity. Although the temperatures at which the PEO and PCL blocks and the PE and PLLA blocks crystallize overlap, the analysis of the intensity changes measured by WAXS and PLOM experiments allows identifying each of the crystallization processes. The quarterpolymer Q1 remarkably self-assembles during crystallization into tetracrystalline banded spherulites, where four types of different lamellae coexist. Nanostructural features arising upon sequential crystallization are found to have a relevant impact on the mechanical properties. Nanoindentation measurements show that storage modulus and hardness of the Q1 quarterpolymer significantly deviate from those of the stiff PE and PLLA blocks, approaching typical values of compliant PEO and PCL. Results are mainly attributed to the low crystallinity of the PE and PLLA blocks. Moreover, the Q2 copolymer exhibits inferior mechanical properties than Q1, and this can be related to the PE block within Q1 that has thinner crystal lamellae according to its much lower melting point.

Graphene and Polyethylene: A Strong Combination Towards Multifunctional Nanocomposites.

The key to the preparation of polymer nanocomposites with new or improved properties resides in the homogeneous dispersion of the filler and in the efficient load transfer between components through strong filler/polymer interfacial interactions. This paper reports on the preparation of a series of nanocomposites of graphene and a polyolefin using different experimental approaches, with the final goal of obtaining multifunctional materials. A high-density polyethylene (HDPE) is employed as the matrix, while unmodified and chemically modified graphene fillers are used. By selecting the correct combination as well as the adequate preparation process, the nanocomposites display optimized thermal and mechanical properties, while also conferring good gas barrier properties and significant levels of electrical conductivity.

Prokaryotic Expression of the Immunoglobulin's Domains of CRTAM to Characterize a Monoclonal Antibody.

Class-I restricted T cell-associated molecule (CRTAM) is a member of the immunoglobulin superfamily, and it is closely related to nectin-like protein. CRTAM is expressed in activated CD8 T cells, NKT cells, NK cells and in a subpopulation CD4 T cells. In this study, we produce as recombinant proteins, the Ig-domains of CRTAM (IgV-IgC), the IgV, and the IgC. These proteins were successfully purified in the soluble fraction only if the stalk region was included. The recombinant CRTAM recognizes its ligand nectin-like 2 in a cell-free system. We also demonstrate that the IgC domain of CRTAM is recognized by the anti-hCRTAM monoclonal antibody C8 with a 0.62 nM affinity. In conclusion, the stalk region of CRTAM provides solubility for the expression of its Ig-domains as recombinant proteins.

Targeted Assessment and Context-Tailored Implementation of Change Strategies (TACTICS) to increase evidence based psychotherapy in military behavioral health clinics: Design of a cluster-randomized stepped-wedge implementation study.

BACKGROUND: Despite efforts by the U.S. Department of Defense to train behavioral health (BH) providers in evidence-based psychotherapies (EBPs) for posttraumatic stress disorder (PTSD), numerous barriers limit EBP implementation. A context-tailored implementation approach called TACTICS (Targeted Assessment and Context-Tailored Implementation of Change Strategies) holds promise for increasing the use of EBPs such as prolonged exposure therapy (PE) in military treatment facilities. TACTICS combines a needs assessment, a rubric for selecting implementation strategies based on local barriers, an implementation toolkit, and external facilitation to support local champions and their implementation teams in enacting changes. This paper describes the rationale for and design of a study that will evaluate whether TACTICS can increase implementation of PE for PTSD and improve patient outcomes in military BH clinics relative to provider training in PE alone. METHODS: The study is a multi-site, cluster randomized, stepped-wedge trial, with the military treatment facility as the unit of analysis. Eight facilities undergo a provider-training phase, followed by 5 months of TACTICS implementation. The timing of TACTICS at each facility is randomly assigned to begin 9, 14, or 19 months after beginning the provider-training phase. Primary analyses will compare the proportion of PTSD patients receiving PE and patients' mean improvement in PTSD symptoms before and after the onset of TACTICS. DISCUSSION: TACTICS endeavors to balance standardization of empirically-supported implementation strategies with the flexibility of application necessary for success across varied clinical settings. If successful, TACTICS may represent a systematic and scalable method of promoting and supporting EBP implementation. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT03663452.

The Use of Virtual Reality to Facilitate Mindfulness Skills Training in Dialectical Behavioral Therapy for Spinal Cord Injury: A Case Study.

Introduction: Paralysis from a spinal cord injury (SCI) increases risk of psychological problems including suicide attempts, substance use disorder, negative emotions (e.g., anger), depression, anxiety, ASD/PTSD. Dialectical Behavioral Therapy® (DBT®) has been shown to be effective for treating similar psychological symptoms in non-SCI patient populations. The current study explored for the first time, the feasibility and clinical potential of using Immersive Virtual Reality (VR) enhanced DBT® Mindfulness skills training to help reduce psychological symptoms (negative emotions and anxiety, ASD/PTSD) of two patients with SCI. Patient 1 was a 39-year-old male patient suffering multiple spinal cord injuries, resulting in quadriplegia, after falling out of a four story building. Patient 1 had severe depression, and anxiety symptoms. Patient 2, was a 31 year old male with a C7 vertebral body fracture, leading to paresis, after suffering a blunt force trauma injury during an attempted suicide, jumping from a moving vehicle. Patient 2 had mild depression, and anxiety symptoms. Methods: Each patient looked into VR goggles, and had the illusion of slowly "floating down" a river in virtual reality while listening to DBT® Mindfulness Skills training instructions. Each patient filled out brief psychological ratings before and after each VR session, four VR DBT® sessions for patient 1, and two VR DBT® sessions for patient 2. Results: As predicted, patient 1 reported reductions in negative emotions after each VR DBT® Mindfulness session. Patient 2 had mixed results on some of the measures of negative emotions. And both patients reported feeling less depressed, less anxious, and less emotionally upset, after VR DBT® Mindfulness Skills learning. Patient 2 reported large reductions in short term ASD/PTSD symptoms after his first VR DBT® mindfulness skills training session. Conclusion: This study explored the feasibility of using VR DBT® with quadriplegic or paresis SCI patients. Both SCI patients accepted VR, the patients liked using VR, and, with assistance from the therapist, the patients were able to use the VR equipment, despite being paralyzed. Additional research and development will be needed to determine whether VR DBT® Mindfulness Skills training leads to any long term improvements in outcome.

First Trimester Prenatal Care Initiation Among Hispanic Women Along the U.S.-Mexico Border.

Background First trimester prenatal care (FTPNC) is associated with improved birth outcomes. U.S.-Mexico border Hispanic women have lower FTPNC than non-border or non-Hispanic women. This study aimed to identify (1) what demographic, knowledge and care-seeking factors influence FTPNC among Hispanic women in border counties served by five Healthy Start sites, and (2) what FTPNC barriers may be unique to this target population. Healthy Starts work to eliminate disparities in perinatal health in areas with high poverty and poor birth outcomes. Methods 403 Hispanic women of reproductive age in border communities of California, Arizona, New Mexico and Texas were surveyed on knowledge and behaviors related to prenatal care (PNC) and basic demographic information. Chi square analyses and logistic regressions were used to identify important relationships. Results Chi square analyses revealed that primiparous women were significantly less likely to start FTPNC than multiparous women (χ2 = 6.8372, p = 0.0089). Women with accurate knowledge about FTPNC were more likely to obtain FTPNC (χ2 = 29.280, p < .001) and more likely to have seen a doctor within the past year (χ2 = 5.550, p = .018). Logistic regression confirmed that multiparity was associated with FTPNC and also that living in Texas was negatively associated with FTPNC (R2 = 0.066, F(9,340) = 2.662, p = .005). Among 27 women with non-FTPNC, barriers included late pregnancy recognition (n = 19) and no medical insurance (n = 5). Conclusions This study supports research that first time pregnancies have lower FTPNC, and demonstrated a strong association between delayed PNC and late pregnancy recognition. Strengthened investments in preconception planning could improve FTPNC in this population.

Voces de la frontera/Voices from the Border: Using Case Studies of Pregnancy, Birth and Parenting along the U.S.-Mexico Border to Identify Shared Measures of Success.

Purpose This research analyzes the cases of five women living along the U.S.-Mexico border who overcame challenges during pregnancy or parenting with the support of a federally funded Healthy Start program, designed to eliminate disparities in perinatal health in disadvantaged communities with the poorest birth outcomes. Study objectives were to: (1) identify common factors that affect healthy maternal and child outcomes for Healthy Start participants; and (2) identify a shared definition of what success looks like for Healthy Start participants and opportunities for further study. Description Five border Healthy Start sites (CA, AZ, NM, and TX) contributed case stories from participants who had overcome access barriers to achieve positive pregnancy, birth or parenting outcomes. Case studies were collected using review of successful participant cases and non-structured interviews by Healthy Start staff, and analyzed using participatory methods and thematic analysis. Assessment Common barriers were: lack of insurance; isolation or unsupportive family relationships; timidness and lack of self-advocacy. Healthy Start programs have been successful in securing supportive relationships through the community health worker model; reducing isolation; obtaining insurance access and a medical home; building self-advocacy skills; and supporting participants to pursue their goals. Conclusion Identified barriers are in line with available literature on health care access and provide a U.S.-Mexico border-specific view. The Healthy Start model is effective at helping women to overcome barriers. Learning from this research may contribute to development of shared measures for more impactful evaluation of Healthy Start and similar programs.

Difficult Patients in the Emergency Department: Personality Disorders and Beyond.

Physician-patient encounters in clinical settings, especially in the emergency department, can be of varying degrees of difficulty. Medically complicated, challenging cases can be paradoxically rewarding, whereas psychologically driven difficulty is frustrating and counterproductive for patient care. This article presents 3 different complementary perspectives on difficult patients: clinical presentations, manifestations of personality traits and disorders in clinical settings, and how physician feelings may affect care. Management strategies are discussed.

A new nucleocytoplasmic RhoGAP protein contributes to control the pathogenicity of Entamoeba histolytica by regulating EhRacC and EhRacD activity.

Small GTPases are signalling molecules that regulate important cellular processes. GTPases are deactivated by GTPase-activating proteins (GAPs). While human GAPs have been intensively studied, no GAP has yet been characterized in Entamoeba histolytica. In this study, we identified and characterized a novel nucleocytoplasmic RhoGAP in E. histolytica termed EhRhoGAPnc. In silico analyses of the domain structure revealed a previously undescribed peptide region within the carboxy-terminal region of EhRhoGAPnc capable of interacting with phosphatidic acid and phosphatidylinositol 3,5-bisphosphate. The full structural GAP domain showed increase GAP activity compared with the minimum region able to display GAP activity, as analysed both by experimental assays and molecular dynamics simulations. Furthermore, we identified amino acid residues that promote interactions between EhRhoGAPnc and its target GTPases EhRacC and EhRacD. Immunofluorescence studies revealed that EhRhoGAPnc colocalized with EhRacC and EhRacD during uroid formation but not during erythrophagocytosis. Interestingly, during erythrophagocytosis of red blood cells, EhRhoGAPnc colocalized with phosphatidic acid and phosphatidylinositol 3,5-bisphosphate. Overexpression of EhRhoGAPnc in E. histolytica led to inhibition of actin adhesion plate formation, migration, adhesion of E. histolytica to MDCK cells and consequently to an impairment of the cytopathic activity.

Mapping the Mechanical Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Banded Spherulites by Nanoindentation.

Nanoindentation provides clear evidence that spherulite banding can be associated with a continuous modulation of mechanical properties from the more compliant peaks to the stiffer valleys. The structural arrangement in polymer-banded spherulites has intrigued scientists for many decades, and the debate has been recently intensified with the advent of new experimental evidence. The present paper approaches this issue by exploring the local mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-ringed spherulites via nanoindentation and discussing the confidence of the results. It was found that storage modulus and hardness across the banding morphology can be described as a sequence of regular oscillations with a periodicity that exactly matches the one observed using optical and atomic force microscopy. Results are consistent with the model of regular twisting of the lamellae, with flat-on arrangement in the low regions and edge-on lamellae in the crests.

Shift, Interrupted: Strategies for Managing Difficult Patients Including Those with Personality Disorders and Somatic Symptoms in the Emergency Department.

Difficult patients are often those who present with a mix of physical and psychiatric symptoms, and seem refractory to usual treatments or reassurance. such patients can include those with personality disorders, those with somatization symptoms; they can come across as entitled, drug-seeking, manipulative, or simply draining to the provider. Such patients are often frequent visitors to Emergency Departments. Other reasons for difficult encounters could be rooted in provider bias or countertransference, rather than sole patient factors. Emergency providers need to have high awareness of these possibilities, and be prepared to manage such situations, otherwise workup can be sub-standard and dangerous medical mistakes can be made.

Evaluation of zirconium as a permanent chemical modifier using synchrotron radiation and imaging techniques for lithium determination in sediment slurry samples by ET AAS.

In the present paper, lithium was determined in river sediment using slurry sampling and electrothermal atomic absorption spectrometry (ET AAS) after L'vov platform coating with zirconium (as a permanent chemical modifier). The performance of this modifier and its distribution on the L'vov platform after different heating cycles were evaluated using synchrotron radiation X-ray fluorescence (SRXRF) and imaging scanning electron microscopy (SEM) techniques. The analytical conditions for lithium determination in river sediment slurries were also investigated and the best conditions were obtained employing 1300 and 2300 degrees C for pyrolysis and atomization temperatures, respectively. In addition, 100mg of sediment samples were prepared using 4.0moll(-1) HNO(3). The Zr-coating permitted lithium determination with good precision and accuracy after 480 heating cycles using the same platform for slurry samples. The sediment samples were collected from five different points of the Cachoeira river, São Paulo, Brazil. The detection and quantification limits were, respectively, 0.07 and 0.23mugl(-1).