Survey of 138 Conjunctival Tumors in the Dominican Republic.

PURPOSE: To report the frequency of conjunctival tumors in the Dominican Republic. METHODS: Retrospective noninterventional case series. One hundred thirty-eight consecutive patients with a conjunctival mass evaluated at two tertiary referral centers from 2010 to 2018. Main outcome measures were frequency of tumors by diagnosis and distribution of tumors relative to patients' age and gender. RESULTS: The mean age at presentation was 41.2 years (median, 42 years; range 10 days - 91 years). There were 83 male patients (60%) and 55 female patients (40%). The three most common specific diagnoses were junctional, compound, and subepithelial naevi (47 [34%]), squamous cell carcinoma (SCC) (26 [19%]) and conjunctival squamous intraepithelial neoplasia (CIN) (17 [12%]). The mean age at detection was 36.5 years for non-malignant tumors and 56.3 years for malignant tumors (p < .001), with a mean difference of 19.8 years at time of diagnosis (95% CI, 10.7-28.8). Benign tumors were more common in children and young adults; malignant and premalignant tumors were more common in mid and older adults (p = .009). Malignant tumors were more common in males (73%) than in females (27%) (p = .04). CONCLUSION: In the Dominican Republic, conjunctival tumors are benign (63%), premalignant (13%) and malignant (24%). Malignant tumors are more common in older adults and men.

Attachment of Acidithiobacillus ferrooxidans to pyrite in fresh and saline water and fitting to Langmuir and Freundlich isotherms.

OBJECTIVE: This study aims to investigate the attachment of Acidithiobacillus ferrooxidans to pyrite in two different environments: fresh and saline water (water with 35 g/L of NaCl or 0.6 M). Adsorption isotherms were analyzed using the Langmuir and Freundlich models. Saline water is water with 35 g/L of NaCl (0.6 M), which is the concentration of NaCl in seawater. The use of raw seawater in mining is becoming relevant in leaching and flotation process. At the same time the use of microorganisms in both processes is gaining attention. For this reason, it is important to study the behavior of adherence of microorganisms to minerals in saline aqueous environments, similar to seawater. RESULTS: The bacteria showed a higher level of attachment to pyrite in fresh water than in saline water. The Langmuir model fitted better the experimental data obtained in fresh water than in saline water with a coefficient of determination (R2) of 0.85 and 0.61 for fresh and saline water, respectively. CONCLUSIONS: This suggests that the bacteria tend to adhere more as a monolayer in fresh than in saline water in the early stage of adhesion.

Attachment of Acidithiobacillus ferrooxidans onto different solid substrates and fitting through Langmuir and Freundlich equations.

Attachments of Acidithiobacillus ferrooxidans ATCC 23270 onto elemental sulfur, quartz and complex chalcopyrite were investigated by analysis of its extracellular polymeric substances as well as applying Langmuir and Freundlich equations. The two equations fitted the adsorption equilibrium data with significant correlation coefficient over 0.9. This indicated that bacterial attachment is complicated and involves Langmuir and Freundlich characterizations. Sulfur-grown cells showed the highest affinity for the three solid substrates. The investigated complex chalcopyrite possessed a higher maximum adsorption capacity for A. ferrooxidans than elemental sulfur or quartz. The Freundlich fitting parameters suggested that quartz had a weaker adsorption capacity and smaller adsorption areas than elemental sulfur or the complex chalcopyrite. It is not the content of total carbohydrates or proteins in EPS but their ratios that determine the affinity differences between cells and substrates.

Atlantoaxial instability associated with an orthotopic os odontoideum: a multimodality imaging assessment.

Radiography, computed tomography (CT), and magnetic resonance imaging exams of the cervical spine were performed in a 29-year-old man who was ultimately diagnosed with an orthotopic os odontoideum during admission for injuries sustained in a motor vehicle collision. Initial radiography suggested either os odontoideum or an acute fracture of the dens. Further imaging with CT and flexion and extension radiographs confirmed os odontoideum and excluded a dens fracture. Although rare, os odontoideum is an important cervical spine anomaly to consider and to distinguish from an acute fracture of the dens.