Novel Bi(2)WO(6)-TiO(2) heterostructures for Rhodamine B degradation under sunlike irradiation

Highly efficient Bi(2)WO(6)-TiO(2) heterostructure is synthesized by means of a hydrothermal method having highly photoactivity for the degradation of Rhodamine B under sunlike irradiation. From the structural characterization it has been demonstrated that TiO(2) is incorporated on the Aurivillius structure. Interesting synergetic effect between TiO(2) and Bi(2)WO(6) leads to an improved charge carrier separation mechanism, causing the excellent photocatalytic performance under sunlike irradiation. The photocatalytic performance of Bi(2)WO(6) and Bi(2)WO(6)-TiO(2) was compared under different irradiation conditions and using increasing Rhodamine B concentration up to 25 ppm. After the photocatalytic analysis of both systems, the mineralization efficiency of the heterostructure appears significantly higher with respect to Bi(2)WO(6).

Deletion analysis of sucrose metabolic genes from a Salmonella plasmid cloned in Escherichia coli K12

The sucrose operon from pUR400, a 78-kbp conjugative Salmonella plasmid, was cloned in Escherichia coli K12. The operon was located in a 5.7-kbp SalI restriction fragment and was subcloned, in each of two possible orientations, using the expression vector pUC18. The insert DNA was restriction mapped and duplicate restriction sites in the insert and in the polylinker of the vector were used to create various deletions promoter distal in the operon sequence. Additional deletions were made with the restriction exonuclease Bal31. Cells containing hybrid plasmids with specified deletions lacked the ability to transport sucrose or were constitutive for hydrolase and/or uptake activities. The scrA (enzyme IIScr) and scrR (regulatory) genes resided within 2900-bp SmaI-SalI DNA fragment and were assigned the order scrB, scrA, scrR. An amplified sucrose-inducible gene product, Mr 68,000, was detected only in the membrane fraction from recombinant cells that contained plasmid with the intact operon sequence. This protein represented 11% of the total membrane protein and was resistant to extraction with 0.5 M sodium chloride, 2% Triton X-100, and 0.5% sodium deoxycholate. The protein did not appear to be the product of either the scrA, scrB, or scrR gene and may therefore represent a previously unidentified membrane-bound sucrose protein. A new gene, scrC, is proposed. In addition, the cloned 5.7-kbp SalI and 2.5-kbp SmaI-SalI DNA fragments failed to hybridize to chromosomal DNA from Bacillus subtilis, Streptococcus lactis, Streptococcus mutans, and Lactobacillus acidophilus as well as to DNA from a sucrose plasmid from Salmonella tennessee. However, the probes showed weak homology with a 20-kbp EcoRI restriction fragment from Klebsiella pneumoniae.

EXAFS study of the Fex/ZrO2 composite nanomaterials obtained by sol-gel synthesis

The local Zr and Fe arrangements in the nanocomposite system Fe(x)/ZrO2 (x=0-0.2) obtained by sol-gel method were studied by EXAFS. The phase composition was found to vary significantly on iron loading. For the samples calcined at 500 or 600 degrees C, at x< or =0.01, the formed ZrO2 is a mixture of monoclinic and tetragonal structures. Only tetragonal structure is revealed at x > or = 0.05 with the exception of Fe0.2/ZrO2, calcined at 500 degrees C, where new non-typically short Zr-Zr distances (3.29, 3.43A) were observed. At low iron loading (less than one monolayer) Fe3+ ions were found to localize within the pre-surface layers of ZrO2 nanoparticles showing property of isolated ions. For greater Fe loading, iron exhibits either two-dimensional layer structure or two-phase system.

Perioperative outcomes in octogenarians undergoing cardiac surgery in Puerto Rico

With the advances in surgical techniques and the advent of an aging population, the application of cardiac surgeries has broadened to include those patients over the age of 80. In order to characterize the in-hospital morbidity and mortality of elderly patients undergoing cardiac surgery at our cardiovascular center, a retrospective review of all medical records of consecutive octogenarian patients was made. Between January 1998 and April 1999, 76 patients (mean age (SD), 82.5 (2.6)) underwent cardiac surgery, of which, 61.8% were males. Surgical procedures consisted of isolated coronary artery bypass grafting (CABG) in 64 patients, isolated aortic valve replacement (AVR) in 4 patients, combined CABG and left carotid endarterectomy in 4 patients, combined CABG and AVR in 2 patients, combined CABG and aortic aneurysm repair in 1 patient and combined AVR and aortic dissection repair in 1 patient. Surgery was elective in 51.3% of patients and seventy-one percent (54) experienced at least one postoperative complication. The most common complication was atrial arrhythmia (28) followed by low cardiac output (23) and pneumonia (16). Hospital mortality occurred in 11 (14.7%) patients, an estimate in agreement with previous published studies on octogenarians. Since the number of patients studied was small, these results require confirmation by other cardiovascular centers in the island. Further research to determine independent predictors of postoperative morbidity and mortality, to assess survival and quality of life after cardiac surgery and to evaluate cost-effectiveness considering new trends in managed health care is warranted.

Racial Experience as an Alternative Operationalization of Race

The study of human variation is central to both social and biomedical sciences, but social and biomedical scientists diverge in how variation is theorized and operationalized. Race is especially problematic because it is a cultural concept that contains implicit and explicit understandings of how collective bodies differ. In this moderately updated article, originally published in Human Biology in 2015 (vol. 87, no. 4, pp. 306-312), we propose an operationalization of race that addresses both racial experience and human biological diversity, placing them within the same ontological sphere. Furthermore, this approach can more effectively advance antiracist pedagogy and politics. We argue that human biological diversity does not have to be in opposition to constructivist notions of race. Rather, racial experience is emphasized as an embodied experience that is as real and as valid as biological variation. By focusing on both racial experience and biological diversity, it becomes more feasible to operationalize race to fruitfully inform the pedagogy and politics of antiracism. To do so, racial experience must be more broadly conceived and should not always equate to negative outcomes. With the recognition that racial experience has the potential to be something other than damaging, an antiracist anthropology can more effectively address issues pertaining to racial health disparities.

Genetic ancestry in Puerto Rican afro-descendants illustrates diverse histories of African diasporic populations

OBJECTIVES

Genetic studies of contemporary Puerto Ricans reflect a demographic history characterized by admixture between Indigenous American, African, and European peoples. While previous studies provide genetic perspectives on the general Puerto Rican population, less is known about the island's sub-populations, specifically Afro-Puerto Ricans.

MATERIALS AND METHODS

In this study, the genetic ancestry of Afro-Puerto Ricans is characterized and compared to other Caribbean populations. Thirty DNA samples collected among self-identified Puerto Ricans of African descent in Loíza (n = 2), Piñones (n = 13), San Juan (n = 2), Mayagüez (n = 9), and Ponce (n = 4), were genotyped at 750,000 loci on the National Geographic Genochip. We then applied unsupervised clustering and dimensionality-reduction methods to detect continental and subcontinental African and European genetic ancestry patterns.

RESULTS

Admixture analyses reveal that on average, the largest genetic ancestry component for Afro-Puerto Ricans is African in origin, followed by European and Indigenous American genetic ancestry components. African biogeographic origins of Afro-Puerto Ricans align most closely with contemporary peoples of Lower Guinea and the Bight of Biafra, while the European genetic ancestry component is most similar to contemporary Iberian, Italian, and Basque populations. These findings contrast with the biogeographic origins of comparative Barbadian and Puerto Rican populations.

DISCUSSION

Our results suggest that while there are similarities with regard to general patterns of genetic ancestry among African descendants in the Caribbean, there is previously unrecognized regional heterogeneity, including among Puerto Rican sub-populations. These results are also consistent with available historical sources, while providing depth absent from the documentary record, particularly with regard to African ancestry.

Etiology and outcome of non-estrogen associated hyperthyroxinemia in euthyroid patients at the San Juan City Hospital

INTRODUCTION

Hyperthyroxinemia does not always equate to hyperthyroidism. Laboratory tests should always be correlated with the clinical picture. A mismatch should make one doubt true hyperthyroidism. The purpose of our study was to assess the etiology of euthyroid hyperthyroxinemia not associated with estrogen use or pregnancy and to review the outcome of those erroneously treated.

METHODS

The medical records of thirteen euthyroid patients with non estrogen associated hyperthyroxinemia were reviewed. They had a complete set of thyroid function tests including free T3 and free T4 by membrane dialysis, TRH stimulation test and thyroid hormone binding panel.

RESULTS

Two diagnostic groups were identified: Hyperthyroxinemia secondary to binding abnormalities (7/13), better known as familial dysalbuminemic hyperthyroxinemia (FDH) and hyperthyroxinemia secondary to Thyroid Hormone Resistance (THR) (6/13). The FDH group had an elevated T4 and FTI, with normal T3RU, TSH, TRH stimulation test but an abnormal thyroid hormone binding panel which was used to confirm the diagnosis. The THR group had two laboratory presentations: Four patients presented with all the thyroid hormone tests elevated (T4, T3, T3RU, FTI) including a free T3 and free T4 by membrane dialysis with a normal TSH and TRH stimulation test and a normal T4 binding panel. This presentation is typical for a TRH patient with a nuclear receptor defect where all the precursos to the defect accumulate. Two patients with THR presented elevated T4 and free T4 but normal T3 and free T3, localizing the defect at the level of the active T4 transport mechanism across the cellular membrane. These two patients had a normal TSH, TRH stimulation test and T4 binding panel. Two patients were treated erroneously with radioactive iodine and became extremely hypothyroid in spite of normal TFTs. Very high dose of thyroid hormone replacement were required to restore euthyroidism.

CONCLUSION

One must suspect these two entities in patients clinically euthyroid who have elevated T4 but non-suppressed TSH. A normal TSH and TRH test confirm euthyroidism. A thyroid hormone binding panel differentiates FDH from THR. Neither group require treatment. If treated erroneously and T4 drops to normal values, one must again induce hyperthyroxinemia to restore euthyroidism in these patients.

[Male pseudohermaphroditism caused by enzymatic deficiency of 17-alpha-hydroxylase. 1st case reported in Puerto Rico]

A 36 year old white female came to our service after having been evaluated on repetitive occasions in the past for a workup of gigantism and acromegalic features. Since childhood she had developed tall stature, frontal bossing, prominence of zygomatic bones, separated teeth, large hands and size 14 shoes. Human growth hormone and somatomedin serum levels had been normal on all occasions tested. Her past history was significant for primary amenorrhea and a 12 year history of hypertension. On physical examination BP was 140/100, height 6' 2", weight 2571 bs. Her phenotype was truly acromegalic. There was absence of axillary and pubic hair with no breast development. External genitalia was of female appearance. Laboratory evaluation showed increased FSH of 88 mlU/ml, increase LH of 65.6 mlU/ml and decreased E2 of 12.6 pg/ml. Other findings were low serum cortisol of 0.2 mg/dl, high ACTH of 344 pg/ml, low 17-Ketosteroids, high pregnenolone levels of 595 mg/dl, low 17-hydroxypregnenolone less than 10 ng/dl, very high aldosterone of 31 ng/dl and suppressed PRA of less than 0.1 ng/ml. A pelvic sonogram showed a right ovoid structure which could represent a gonad and failed to identify the uterus and left gonad. A bone densitometry showed a decrease bone mineral density compatible with osteoporosis. Chromosome study showed a karyotype of 46-XY. A diagnosis was made of congenital adrenal hyperplasia secondary to 17-alpha-hydroxylase deficiency in a genotypic male. Our patient was referred to the department of gynecology for surgical removal of the gonads. It is amazing how a patient with severe adrenal insufficiency can withstand 36 years of her life undiagnosed without going into an adrenal crisis. Her tall stature and acromegalic features were the striking signs confusing all physicians and delaying the correct diagnosis and appropriate treatment. There has been reported worldwide, nearly 120 cases with documented severe 17-alpha-hydroxylase deficiency. To our knowledge this is the first case identified in Puerto Rico of male pseudohermaphroditism secondary to 17-alpha-hydroxylase enzyme deficiency.