CdTe Quantum Dots Modified with Cysteamine: A New Efficient Nanosensor for the Determination of Folic Acid.

In this paper, we report the synthesis, characterization, and application of a new fluorescent nanosensor based on water-soluble CdTe quantum dots (QDs) coated with cysteamine (CA) for the determination of folic acid (FA). CdTe/CA QDs were characterized by high-resolution transmission electron microscopy, the zeta potential, and Fourier-transform infrared (FT-IR), UV-visible, and fluorescence spectroscopy. CdTe QDs coated with mercaptopropionic acid (MPA) and glutathione (GSH) were prepared for comparison purposes. The effect of FA on the photoluminescence intensity of the three thiol-capped QDs at pH 8 was studied. Only CdTe/CA QDs showed a notable fluorescence quenching in the presence of FA. Then, a nanosensor based on the fluorescence quenching of the CdTe QDs at pH 8 was explored. Under optimum conditions, the calibration curve showed a linear fluorescence quenching response in a concentration range of FA from 0.16 to 16.4 µM (R2 = 0.9944), with a detection limit of 0.048 µM. A probable mechanism of fluorescence quenching was proposed. The nanosensor showed good selectivity over other possible interferences. This method has been applied for FA quantification in orange beverage samples with excellent results (recoveries from 98.3 to 103.9%). The good selectivity, sensitivity, low cost, and rapidity make CdTe /CA QDs a suitable nanosensor for FA determination.

LIM domain-binding 1 maintains the terminally differentiated state of pancreatic ß cells.

The recognition of ß cell dedifferentiation in type 2 diabetes raises the translational relevance of mechanisms that direct and maintain ß cell identity. LIM domain-binding protein 1 (LDB1) nucleates multimeric transcriptional complexes and establishes promoter-enhancer looping, thereby directing fate assignment and maturation of progenitor populations. Many terminally differentiated endocrine cell types, however, remain enriched for LDB1, but its role is unknown. Here, we have demonstrated a requirement for LDB1 in maintaining the terminally differentiated status of pancreatic ß cells. Inducible ablation of LDB1 in mature ß cells impaired insulin secretion and glucose homeostasis. Transcriptomic analysis of LDB1-depleted ß cells revealed the collapse of the terminally differentiated gene program, indicated by a loss of ß cell identity genes and induction of the endocrine progenitor factor neurogenin 3 (NEUROG3). Lineage tracing confirmed that LDB1-depleted, insulin-negative ß cells express NEUROG3 but do not adopt alternate endocrine cell fates. In primary mouse islets, LDB1 and its LIM homeodomain-binding partner islet 1 (ISL1) were coenriched at chromatin sites occupied by pancreatic and duodenal homeobox 1 (PDX1), NK6 homeobox 1 (NKX6.1), forkhead box A2 (FOXA2), and NK2 homeobox 2 (NKX2.2) - factors that co-occupy active enhancers in 3D chromatin domains in human islets. Indeed, LDB1 was enriched at active enhancers in human islets. Thus, LDB1 maintains the terminally differentiated state of ß cells and is a component of active enhancers in both murine and human islets.

Mentoring Hispanic undergraduate and graduate research assistants: building research capacity in nursing.

BACKGROUND: This article discusses and describes the experiences of five Hispanic bilingual (English and Spanish) research assistants (RAs) who were undergraduate and graduate nursing students and who were part of a research team. METHOD: A capacity-building framework was used, which has six guiding principles: a whole-system approach; accommodating diversity; reducing barriers to participation; enabling collaboration; mentoring; and facilitating networking. In addition, mentorship and peer learning were essential components of building research capacity. RESULTS: Reflections of the five RAs highlighting how these principles were applied are described. The experiences of the five Hispanic RAs and the outcomes of the projects are also described. CONCLUSION: These experiences demonstrate the importance of involving undergraduate and graduate nursing students in research, which can build research capacity and increase the number of Hispanic nurses in the workforce.

Understanding diabetes self-management behaviors among Hispanics in New York City.

Diabetes mellitus is a public health concern disproportionately affecting Hispanics. Because Hispanics are greatly affected by a high prevalence of diabetes, a qualitative study was conducted, which explored how Hispanics understand, perceive, and experience behavioral change and how they maintain such change while managing their diabetes. Twenty Caribbean (Dominican and Puerto Rican) Hispanic adults with diabetes, who were either English- or Spanish-speaking, participated in the study. Twenty individual interviews were conducted, audiotaped, and transcribed and translated. Structured questions were used in the interviews which covered the meaning of certain terms (e.g., healthy eating, exercise), motivators and barriers to changing behaviors related to diabetes management, and a question to explore ways nurses can assist them in changing behaviors. Content analysis was used to analyze the text of the interviews. Three themes (diabetes management, behavior change, and nurse's role) emerged from the data, including apparent gaps in the participants' perception of adapting their cultural foods into healthier dietary habits.