A solvent impregnated hollow fibre (SIHF) module has been developed for the preconcentration of lead by using bis(2-ethylhexyl) phosphoric acid (DEHPA) dissolved in kerosene as extractant. The module ...has been designed for an on-line determination of trace amounts of lead(II) at mg
l
−1 (ppm) level by flame atomic absorption spectrometry (FAAS).
The SIHF system is based on the metal liquid–liquid distribution between aqueous solutions of different acidity and the mentioned organic solution. The highest enrichment factor of Pb(II) was determined at pH=4.0 using a formic acid/formiate buffer solution.
Preconcentration experiments were carried out at low lead(II) concentration (mg
l
−1 level) by using the SIHF module. This study includes the influence of hydrodynamic and chemical conditions on the loading and elution of Pb(II) on the SIHF, i.e., flow rate through the fibres, acidity of the eluent (as nitric acid concentration) and the chemical nature of the acid used in the elution. Breakthrough curves were determined for different sampling flow rates, 0.54
ml
min
−1 was selected to minimise the loading volume of Pb(II) sample. 0.1
M nitric acid was chosen as eluent solution, and perchloric acid also shows appropriate elution characteristics. The degree of concentration obtained for Pb(II) are of 10 fold the original concentration. The quantification limit for Pb(II) achieved with this preconcentration system is 0.17
mg
l
−1.
The results obtained indicate that the SIHF system can be applied for on-line determination of trace amounts of lead(II) by FAAS.
A hollow fiber supported liquid membrane (HFSLM) system for the separation and concentration of vanadium (V) has been developed and characterized by using tricaprylylmethylammonium chloride (Aliquat ...336®) dissolved in dodecane as carrier. The transport of vanadium through the liquid membrane is based on a pH gradient between feed and stripping solutions to provide an appropriate change on the chemical species of aqueous vanadate, i.e., aqueous metavanadate, VO
2(OH)
2
−1 (4.0 < pH < 7.0) is extracted by Aliquat 336 and VO
3OH
2− (pH > 8.0) is not extracted. Selective separation and concentration experiments were carried out at low vanadium(V) concentration (mg 1
−1 level). The study of the HFSLM includes the influence of hydrodynamic, physical and chemical conditions, i.e., flow rate of feed solution through the fibers, number and length of fibers, lifetime of the system, initial vanadium concentration in the feed solution, and pH of aqueous phases. Transport of V(V) increases with the flow rate of the feed solution through the fibers until a ‘plateau’ is reached (> 0.2 ml min
−1 in a single fiber). It has been shown that in a HFSLM module, the membrane area increases with the number of fibers but also there is an increase of the sterical hindrance between the fibers which reduces the expected increase of vanadium transport. On the other hand, the length of the fibers has a scarce influence on the transport process. The effect of the acidity of the feed solution on the vanadium transport shows a similar behavior to that obtained previously for liquid-liquid distribution and laminar SLM studies. The results obtained indicate that vanadium(V) can be effectively concentrated and selectively separated by hollow fiber SLM containing Aliquat 336® as carrier.
Celebrating Flippancy James M. Sutton; Catherine Socarras Ferrell; Ana Menéndez ...
Shakespeare and Latinidad,
04/2021
Book Chapter
I have been teaching Latinx students Shakespeare for twenty-five years at Florida International University (FIU), Miami’s public research institution. Since its opening in 1972, FIU’s students have ...mirrored the diverse population of Miami-Dade County and southern Florida. Consequently, although FIU enrolls Caucasian, African and African-diasporic, and Asian students, most of our students are Latinx. Primarily they are Caribbean Latinx, claiming origins in Cuba, the Dominican Republic or Puerto Rico. Many more, though, have ties to Mexico and Central or South America, including Nicaragua, Honduras, Guatemala, Colombia, Venezuela, Peru and Argentina. Thus, like Miami, FIU’s Latinx composition is a mosaic rather
A group of 70 patients with locally advanced non-small-cell lung cancer (LA-NSCLC), treated in different phase II–III trials with platinum-based chemotherapy in two institutions, have been evaluated ...to identify potential baseline prognostic factors predicting their survival. The eligibility criteria were patients with stage IIIA (N2)-IIIB, Eastern Cooperative Oncology Group performance status 0.1 and less than 5% weight loss. All 37 patients with stage IIIA(N2) were treated with platinum-based induction chemotherapy followed by surgery plus radiotherapy if no progression was observed. The other 33 patients with stage IIIB were treated with platinum-based induction chemotherapy followed by conventional fractionation radiotherapy if no progression was observed. The overall response rate to induction chemotherapy was 40%. Median survival of the 70 patients was 13 months, with a 4-year survival of 15%. At univariate analysis, two prognostic factors correlated with survival: partial or complete response to induction chemotherapy (
P<0.00001) and bulky mediastinal lymph nodes (N2>2.5 cm) (
P=0.03). At multivariate analysis, only the response to induction chemotherapy retained statistical significance (
P=0.00001). Randomized well-balanced prospective trials considering initially mediastinal N2 node size are needed to clearly establish the role of chemotherapy, surgery and radiotherapy in LA-NSCLC.
We report the observation and physical characterization of the possible dwarf planet \UZ\ ("DeeDee"), a dynamically detached trans-Neptunian object discovered at 92 AU. This object is currently the ...second-most distant known trans-Neptunian object with reported orbital elements, surpassed in distance only by the dwarf planet Eris. The object was discovered with an \(r\)-band magnitude of 23.0 in data collected by the Dark Energy Survey between 2014 and 2016. Its 1140-year orbit has \((a,e,i) = (109~\mathrm{AU}, 0.65, 26.8^{\circ})\). It will reach its perihelion distance of 38 AU in the year 2142. Integrations of its orbit show it to be dynamically stable on Gyr timescales, with only weak interactions with Neptune. We have performed followup observations with ALMA, using 3 hours of on-source integration time to measure the object's thermal emission in the Rayleigh-Jeans tail. The signal is detected at 7\(\sigma\) significance, from which we determine a \(V\)-band albedo of \(13.1^{+3.3}_{-2.4}\mathrm{(stat)}^{+2.0}_{-1.4}\mathrm{(sys)}\) percent and a diameter of \(635^{+57}_{-61}\mathrm{(stat)}^{+32}_{-39}\mathrm{(sys)}\)~km, assuming a spherical body with uniform surface properties.
Thirty-one patients with non-small-cell lung cancer (NSCLC), stage III (T3 N2 M 0-1), were treated with cyclophosphamide (400 mg/m2), adriamycin (40 mg/m2) and cisplatin (60 mg/m2) (CAP) every 4 ...weeks for 8 cycles. Twenty-six patients were evaluable for response. Patients characteristics included: median age, 63 years; median performance status, 70% (range 60%-100%). One hundred and fifty-five cycles of chemotherapy were administered with a median of 5. There were 9 partial responses and 3 complete remissions, for an overall response rate of 46%. The median survival duration was 9 months, and 29% survived 1 year. CAP combination chemotherapy was well tolerated without nephrotoxicity, which can be imputed to the strong saline hydration given. Seventy percent of the patients did not experience emesis due to the antiemetic regimen used.
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