The Influence of Voxelotor on Cerebral Blood Flow and Oxygen Extraction in Pediatric Sickle Cell Disease

Voxelotor is an inhibitor of sickle hemoglobin polymerization that is used to treat sickle cell disease. While voxelotor has been shown to improve anemia, the clinical benefit on the brain remains to be determined. This study quantified the cerebral hemodynamic effects of voxelotor in children with sickle cell anemia (SCA) using non-invasive diffuse optical spectroscopies. Specifically, frequency-domain near-infrared spectroscopy (FDNIRS) combined with diffuse correlation spectroscopy (DCS) were used to noninvasively assess regional oxygen extraction fraction (OEF), cerebral blood volume (CBV), and an index of cerebral blood flow (CBFi). Estimates of CBFi were first validated against arterial spin-labeled magnetic resonance imaging (ASL-MRI) in 8 children with SCA ages 8-18 y. CBFi was significantly positively correlated with ASL-MRI-measured blood flow (R2 = 0.651, p = 0.015). Next, a single-center, open label pilot study was completed in 8 children with SCA ages 4-17 y on voxelotor monitored prior to treatment initiation, and at 4, 8, and 12 weeks (NCT05018728). By 4 w, both OEF and CBFi significantly decreased, and these decreases persisted to 12 w (both p < 0.05). Decreases in CBFi were significantly correlated with increases in blood hemoglobin concentration (p = 0.025), while the correlation between decreases in OEF and increases in hemoglobin trended towards significance (p = 0.12). Given that previous work has shown that oxygen extraction and blood flow are elevated in pediatric SCA compared to controls, these results suggest that voxelotor may reduce cerebral hemodynamic impairments.

Diagnostic Excellence in Pediatric Spine Imaging: Using Contextualized Imaging Protocols

Contextual design and selection of MRI protocols is critical for making an accurate diagnosis given the wide variety of clinical indications for spine imaging in children. Here, we describe our pediatric spine imaging protocols in detail, tailored to specific clinical questions.

Ferrocene tethered boramidinate frustrated Lewis pairs: stepwise capture of CO2 and CO

The synthesis and reactivity of novel ferrocene tethered boramidinate frustrated Lewis pairs (FLPs), capable of the sequential capture of small molecules, is reported. Reactions of 1,1'-dicarbodiimidoferrocenes with different boranes provides access to metallocene tethered FLPs. The reactivity of the boramidinate moieties can be tuned by the nature of the carbodiimido substituents (alkyl vs. aryl) and the borane used in the reduction (9-borabicyclo[3.3.1]nonane [(C₈H₁₄)₂BH]₂vs. bis-pentafluorophenyl borane [(C₆F₅)₂BH]₂). The boramidinate FLP arms do not engage in intramolecular reactions, allowing for independent small molecule capture by each FLP. By careful synthetic control, sequential capture of different gaseous small molecules (CO₂ and CO or CO₂ and CNtBu) by the same bis(boramidinate)ferrocene molecule has been demonstrated.

Quantitative renal magnetic resonance imaging: magnetic resonance urography

The goal of functional renal imaging is to identify and quantitate irreversible renal damage and nephron loss, as well as potentially reversible hemodynamic changes. MR urography has evolved into a comprehensive evaluation of the urinary tract that combines anatomical imaging with functional evaluation in a single test without ionizing radiation. Quantitative functional MR imaging is based on dynamic contrast-enhanced MR acquisitions that provide progressive, visible enhancement of the renal parenchyma and urinary tract. The signal changes related to perfusion, concentration and excretion of the contrast agent can be evaluated using both quantitative and qualitative measures. Functional evaluation with MR has continued to improve as a result of significant technical advances allowing for faster image acquisition as well as the development of new tracer kinetic models of renal function. The most common indications for MR urography in children are the evaluation of congenital anomalies of the kidney and urinary tract including hydronephrosis and renal malformations, and the identification of ectopic ureters in children with incontinence. In this paper, we review the underlying acquisition schemes and techniques used to generate quantitative functional parameters including the differential renal function (DRF), asymmetry index, mean transit time (MTT), signal intensity versus time curves as well as the calculation of individual kidney glomerular filtration rate (GFR). Visual inspection and semi-quantitative assessment using the renal transit time (RTT) and calyceal transit times (CTT) are fundamental to accurate diagnosis and are used as a basis for the interpretation of the quantitative data. The importance of visual assessment of the images cannot be overstated when analyzing the quantitative measures of renal function.

COVID-19 Related Experiences Among College Students With and Without Disabilities: Psychosocial Impacts, Supports, and Virtual Learning Environments

This cross-sectional analysis estimated differences, based on disability status, in college students' (n = 777) experiences during the COVID-19 pandemic. Data were modeled using t-tests and logistic regression. Most participants were white (86.2%), and women (66.4%). The mode age was 23. A third (35.6%) had at least one disability. Students reported high rates of psychosocial distress, like fear of contracting (59.7%) and spreading (74.3%) COVID-19, worry about friends and family (83.7%), and increased anxiety (72.5%), depression (59.9%), and substance use (24.7%). Forty-two percent (42.2%) were scared they would miss out on their education through virtual classes. About a third feared forgetting assignments (34.1%) and making mistakes (33.9%). Fewer students expressed apprehension about (27.9%) and intimidation by (26.3%) virtual learning. Only 17.2% would continue taking virtual classes after the pandemic. Students with disabilities (M = 12.4, SD = 4.1) experienced more psychosocial stressors compared to students without disabilities (M = 9.9, SD = 4.2), [t₍₇₇₅₎ = 7.86, p < 0.001]. In adjusted models, disabled students were more than twice as likely to experience worry about medical bills (OR = 2.29), loneliness (OR = 2.09), and increased anxiety (OR = 2.31). They were also more than three times as likely to report increased depression (OR = 3.51) and changes in sexual activity (OR = 3.12). However, students with disabilities (M = 1.5, SD = 1.1) also reported receiving more support compared to their non-disabled classmates (M = 1.1, SD = 1.1), [t₍₇₇₅₎ = 6.06, p < 0.001]. Disabled students were more likely to feel a sense of contributing to society by following precautions (OR = 1.80) and receive support from family and others (emotional support: OR = 2.01, financial support: OR = 2.04). Interestingly, no significant differences were found in students' feelings associated with online or virtual learning [t_(526.08) = 0.42, p = 0.68]. Students with disabilities, though, trended toward reporting negative experiences with virtual learning. In conclusion, students with disabilities were disproportionately affected by COVID-19 stressors, but also expressed more support and a sense of contributing to the common good.

Utilization of 3D MRI for the Evaluation of Sphincter Pharyngoplasty Insertion Site in Patients With Velopharyngeal Dysfunction

Sphincter pharyngoplasty is a surgical method to treat velopharyngeal dysfunction. However, surgical failure is often noted and postoperative assessment frequently reveals low-set pharyngoplasties. Past studies have not quantified pharyngoplasty tissue changes that occur postoperatively and gaps remain related to the patient-specific variables that influence postoperative change. The purpose of this study was to utilize advanced three-dimensional imaging and volumetric magnetic resonance imaging (MRI) data to visualize and quantify pharyngoplasty insertion site and postsurgical tissue changes over time.

A prospective, repeated measures design was used for the assessment of craniometric and velopharyngeal variables postsurgically. Imaging was completed across two postoperative time points. Tissue migration, pharyngoplasty dimensions, and predictors of change were analyzed across imaging time points.

Significant differences were present between the initial location of pharyngoplasty tissue and the pharyngoplasty location 2 to 4 months postoperatively. The average postoperative inferior movement of pharyngoplasty tissue was 6.82 mm, although notable variability was present across participants. The pharyngoplasty volume decreased by 30%, on average.

Inferior migration of the pharyngoplasty tissue was present in all patients. Gravity, scar contracture, and patient-specific variables likely interact, impacting final postoperative pharyngoplasty location. The use of advanced imaging modalities, such as 3D MRI, allows for the quantification and visualization of tissue change. There is a need for continued identification of patient-specific factors that may impact the amount of inferior tissue migration and scar contracture postoperatively.

Antibacterial Thiamine inspired silver (I) and gold (I) N-heterocyclic carbene compounds

Three new coinage metal carbene complexes of silver and gold were synthesized from a thiamine inspired proligand. The compounds were characterized by HRMS, NMR spectroscopy (1H, 19F, 31P and 13C), FT-IR and elemental analysis. The coordination environment around the metal centers was correlated to the diffusion coefficients obtained from DOSY-NMR experiments and was in agreement with the nuclearity observed in the solid-state by single crystal X-ray crystallography. The silver and gold carbene compounds were subjected to MIC studies against a panel of pathogenic bacteria, including multidrug resistant strains, with the gold carbene derivative showing the most potent antimicrobial activity against Gram-positive methicillin resistant Staphylococcus aureus (MRSA).

Somatic Mutations and the Risk of Undifferentiated Autoinflammatory Disease in MDS: An Under-Recognized but Prognostically Important Complication

Objectives: We theorized that myelodysplastic syndrome (MDS) with somatic mutations and karyotype abnormalities are associated with autoinflammation, and that the presence of autoinflammatory disease affected prognosis in MDS. Methods: One hundred thirty-four MDS patients were assessed for the prevalence of autoinflammatory complications and its link with karyotypes and somatic mutation status. Autoinflammatory complications were described either as well-defined autoinflammatory diseases (AD) or undifferentiated "autoinflammatory disease" (UAD) (defined as CRP over 10.0 mg/L on five consecutive occasions, taken at separate times and not explained by infection). Several patient characteristics including demographic, clinical, laboratory, cytogenetics charts, and outcomes, were compared between different groups. Results: Sixty-two (46.3%) patients had an autoinflammatory complication manifesting as arthralgia (43.5% vs. 23.6%, p = 0.0146), arthritis (30.6% vs. 15.3%, p = 0.0340), skin rash (27.4% vs. 12.5%, p = 0.0301), pleuritis (14.5% vs. 4.2%, p = 0.0371) and unexplained fever (27.4% vs. 0%, p < 0.0001). AD were found in 7.4% of MDS patients (with polymyalgia rheumatic being the most frequently one). Classical autoimmune diseases were found only in 4 MDS patients (3.0%). Transcription factor pathway mutations (RUNX1, BCOR, WTI, TP53) (OR 2.20 [95%CI 1.02-4.75], p = 0.0451) and abnormal karyotypes (OR 2.76 [95%CI 1.22-6.26], p = 0.0153) were associated with autoinflammatory complications. Acute leukaemic transformation was more frequent in MDS patients with autoinflammatory features than those without (27.4% vs. 9.7%, p = 0.0080). Conclusions: Autoinflammatory complications are common in MDS. Somatic mutations of transcription factor pathways and abnormal karyotypes are associated with greater risk of autoinflammatory complications, which are themselves linked to malignant transformation and a worse prognosis.

Modulating extraction and retention of fluorinated β-diketonate metal complexes in perfluorocarbons through the use of non-fluorinated neutral ligands

Extraction of metal ions into perfluorocarbon solvent with a fluorinated acac ligand is described as well as synergistic extraction with neutral nitrogen donor ligands. Applications include catalysis, nuclear fuels reprocessing, and medical imaging.

Construction of a High-Nuclearity Elliptical Yb(III) Nanoring: NIR Luminescent Response to Metal Ions and Nitro Explosives

One 14-metal Yb(III) nanoring [Yb₁₄(HL)₂L₂₀(DMF)₈(H₂O)₈] (1) with a size of about 1.1 × 2.5 × 2.7 nm was synthesized from a tridentate ligand. Under the excitation of ligand absorption bands, 1 exhibits the NIR luminescence of Yb(III) and displays high luminescence sensitivity and selectivity to Co(II), Cu(II), and 2,4,6-trinitrophenol (PA) at the parts per million level. The K_SV values of 1 to Co(II), Cu(II), and PA are 6.0 × 10⁴ M^-1, 3.8 × 10⁴ M^-1, and 6.9 × 10⁴ M^-1, respectively. 1 exhibits high luminescent sensitivity to PA even in the presence of other explosives.

Construction of 14-metal lanthanide nanorings with NIR luminescence response to ions

Two 14-metal lanthanide nanorings [Ln14(HL)2L20(DMF)8(H2O)8] (Ln = Nd(1) and Gd(2)) were constructed from a tridentate ligand. 1 displays NIR luminescence sensing properties towards metal cations and anions, especially Cu2+, Co2+, H2PO4- and F- at a ppm level.

Construction of Chiral "Triple-Decker" Nd(III) Nanocluster with High NIR Luminescence Sensitivity toward Co(II)

One Nd(III) complex [Nd₃L₃(OAc)₃] (1) was synthesized from a conjugate Schiff base ligand H₂L. It shows a chiral "triple-decker" structure (1.1 × 1.2 × 1.8 nm) with Nd(III) ions sandwiched between the Schiff base ligands. 1 exhibits NIR Nd(III) luminescence, and the LMET efficiency is calculated to be 13.8%. It displays high luminescence sensitivity and selectivity to Co(II). The K_SV value and LOD of 1 to Co(II) are 9.96 × 10⁴ M^-1 and 0.97 μM, respectively.

Biological variation of cardiac troponins in chronic kidney disease

Background

Patients with chronic kidney disease often have increased plasma cardiac troponin concentration in the absence of myocardial infarction. Incidence of myocardial infarction is high in this population, and diagnosis, particularly of non ST-segment elevation myocardial infarction (NSTEMI), is challenging. Knowledge of biological variation aids understanding of serial cardiac troponin measurements and could improve interpretation in clinical practice. The National Academy of Clinical Biochemistry (NACB) recommended the use of a 20% reference change value in patients with kidney failure. The aim of this study was to calculate the biological variation of cardiac troponin I and cardiac troponin T in patients with moderate chronic kidney disease (glomerular filtration rate [GFR] 30–59 mL/min/1.73 m2).

Methods and results

Plasma samples were obtained from 20 patients (median GFR 43.0 mL/min/1.73 m2) once a week for four consecutive weeks. Cardiac troponin I (Abbott ARCHITECT® i2000SR, median 4.3 ng/L, upper 99th percentile of reference population 26.2 ng/L) and cardiac troponin T (Roche Cobas® e601, median 11.8 ng/L, upper 99th percentile of reference population 14 ng/L) were measured in duplicate using high-sensitivity assays. After outlier removal and log transformation, 18 patients’ data were subject to ANOVA, and within-subject (CVI), between-subject (CVG) and analytical (CVA) variation calculated. Variation for cardiac troponin I was 15.0%, 105.6%, 8.3%, respectively, and for cardiac troponin T 7.4%, 78.4%, 3.1%, respectively. Reference change values for increasing and decreasing troponin concentrations were +60%/–38% for cardiac troponin I and +25%/–20% for cardiac troponin T.

Conclusions

The observed reference change value for cardiac troponin T is broadly compatible with the NACB recommendation, but for cardiac troponin I, larger changes are required to define significant change. The incorporation of separate RCVs for cardiac troponin I and cardiac troponin T, and separate RCVs for rising and falling concentrations of cardiac troponin, should be considered when developing guidance for interpretation of sequential cardiac troponin measurements.

Electropolymerizable N-heterocyclic carbene complexes of Rh and Ir with enantiotropic polymorphic phases

New Rh (1) and Ir (2) complexes of an N-heterocyclic carbene (NHC) featuring a terthiophene backbone were synthesized. Single crystal X-ray diffraction studies of 1 and 2 at 100 K and 298 K respectively, revealed two enantiotropic polymorphic phases with similar lattice parameters for each compound. The transition temperature between two crystalline forms for each compound was determined by measuring the percentage of reflections with a different space group ranging from 100 K to 298 K. Both 1 and 2 were also found to catalyze the hydrogen transfer reaction. The conducting metallopolymers poly-1 and poly-2 were synthesized from oxidative electropolymerization of 1 and 2, respectively, in CH₂Cl₂ electrolyte solution on indium tin oxide-(ITO) coated glass. The electrochromic properties of synthesized conducting metallopolymers were studied by UV-vis-NIR spectroelectrochemistry.

A 42-metal Yb(iii) nanowheel with NIR luminescent response to anions

One Yb42 nanowheel [Yb42L14(OH)28(OAc)84] was constructed using a tridentate vanillin ligand. The external diameter of the wheel-like structure is about 3.6 nm, which allows direct visualization by TEM. It shows interesting NIR lanthanide luminescence sensing towards anions, especially to fluoride at the ppm level.

Construction of a 1-D Sm(iii) coordination polymer with a long-chain Schiff base ligand: dual-emissive response to metal ions

A 1-D coordination polymer [Sm(HL)₂(NO₃)]_n was constructed using a new flexible Schiff base ligand that has a long-chain (CH₂)₁₀ backbone, and it shows dual-emissive response to metal ions, especially to Co²⁺ at the ppm level.

Interleukin-1β drives NEDD8 nuclear-to-cytoplasmic translocation, fostering parkin activation via NEDD8 binding to the P-ubiquitin activating site

Background

Neuroinflammation, typified by elevated levels of interleukin-1 (IL-1) α and β, and deficits in proteostasis, characterized by accumulation of polyubiquitinated proteins and other aggregates, are associated with neurodegenerative disease independently and through interactions of the two phenomena. We investigated the influence of IL-1β on ubiquitination via its impact on activation of the E3 ligase parkin by either phosphorylated ubiquitin (P-Ub) or NEDD8.

Methods

Immunohistochemistry and Proximity Ligation Assay were used to assess colocalization of parkin with P-tau or NEDD8 in hippocampus from Alzheimer patients (AD) and controls. IL-1β effects on PINK1, P-Ub, parkin, P-parkin, and GSK3β—as well as phosphorylation of parkin by GSK3β—were assessed in cell cultures by western immunoblot, using two inhibitors and siRNA knockdown to suppress GSK3β. Computer modeling characterized the binding and the effects of P-Ub and NEDD8 on parkin. IL-1α, IL-1β, and parkin gene expression was assessed by RT-PCR in brains of 2- and 17-month-old PD-APP mice and wild-type littermates.

Results

IL-1α, IL-1β, and parkin mRNA levels were higher in PD-APP mice compared with wild-type littermates, and IL-1α-laden glia surrounded parkin- and P-tau-laden neurons in human AD. Such neurons showed a nuclear-to-cytoplasmic translocation of NEDD8 that was mimicked in IL-1β-treated primary neuronal cultures. These cultures also showed higher parkin levels and GSK3β-induced parkin phosphorylation; PINK1 levels were suppressed. In silico simulation predicted that binding of either P-Ub or NEDD8 at a singular position on parkin opens the UBL domain, exposing Ser₆₅ for parkin activation.

Conclusions

The promotion of parkin- and NEDD8-mediated ubiquitination by IL-1β is consistent with an acute neuroprotective role. However, accumulations of P-tau and P-Ub and other elements of proteostasis, such as translocated NEDD8, in AD and in response to IL-1β suggest either over-stimulation or a proteostatic failure that may result from chronic IL-1β elevation, easily envisioned considering its early induction in Down’s syndrome and mild cognitive impairment. The findings further link autophagy and neuroinflammation, two important aspects of AD pathogenesis, which have previously been only loosely related.

Synthesis and electropolymerization of N-heterocyclic carbene complexes of Pd(ii) and Pt(ii) from an emissive imidazolium salt with a terthiophene backbone

The synthesis of an emissive terthiophene-based imidazolium iodide: 1,3-dimethyl-4,6-di(thiophen-2-yl)-thienoimidazol-3-ium iodide (4), the corresponding N-heterocyclic carbene (NHC) preligand, and Pd and Pt-NHC complexes (5a, 5b) are reported. A related Pd-NHC complex (8) with a mono-thiophene backbone has also been synthesized. The solid-state structures were determined by single crystal X-ray diffraction studies. Compounds 4, 5a and 5b were characterized by absorption/emission spectroscopy and an emission-quench phenomenon of 5a was observed. The Pd complexes 5a and 8 were shown to catalyze Heck type C-C bond forming reactions. The compounds with terthiophene backbones (4, 5a, 5b) were electropolymerized onto indium tin oxide (ITO)-coated glass electrodes to yield thin films of conducting metallopolymers (CMPs) (P1-3). UV-vis-NIR spectroelectrochemistry data of P1-3 showed reversible color changes upon oxidation due to the generation of charge carrier species along the polythiophene backbones.

NIR luminescence for the detection of metal ions and nitro explosives based on a grape-like nine-nuclear Nd(iii) nanocluster

A Nd(iii) nanocluster with long Schiff base ligand shows interesting NIR luminescent sensing of both metal cations and nitro explosives, and exhibits high sensitivity to Cd²⁺, Zn²⁺, Cu²⁺, Co²⁺ ions and explosive HMX at the ppm level.

Large Ln42 coordination nanorings: NIR luminescence sensing of metal ions and nitro explosives

Two 42-metal lanthanide nanorings [Ln₄₂L₁₄(OH)₂₈(OAc)₈₄] (Ln = Nd (1), La (2)) were constructed, and the Nd₄₂ cluster exhibits NIR luminescent sensing of metal cations and nitro explosives.

Construction of a crystalline 14-metal Zn–Nd rectangular nanocluster with a dual-emissive response towards metal ions

A crystalline 14-metal Zn–Nd cluster [Zn₆Nd₈L₂(OAc)₂₀(O)₂(NO₃)₄(OC₂H₅)₄] (1) was constructed using a flexible Schiff base ligand with long-chain (CH₂)₂O(CH₂)₂O(CH₂)₂ backbone. 1 exhibits a nanoscale rectangular structure (10 × 14 × 18 Å). Besides the visible ligand-centered emission, 1 displays typical NIR luminescence of Nd³⁺. Interestingly, 1 shows both a ligand-centered and lanthanide fluorescence response towards metal ions, especially to K⁺ and Co²⁺ at the ppm level.

A crystalline 14-metal Zn–Nd nanocluster was constructed, and it shows ligand-centered and lanthanide fluorescence response towards metal ions.

Gross motor skills of South African preschool-aged children across different income settings

OBJECTIVES

No studies have investigated gross motor skill (GMS) proficiency of preschool-aged children across different income settings in South Africa. Research from high-income countries suggests that children from low-income settings display poorer GMS proficiency compared to higher-income peers. This study aimed to (1) describe GMS proficiency of preschool-aged children in urban high-income (UH), urban low-income (UL) and rural low-income (RL) settings; and (2) explore differences in proficiency between income settings and sex.

DESIGN

Descriptive cross-sectional study.

METHODS

The Test of Gross Motor Development-Edition 2 (TGMD-2) was used to assess GMS. The TGMD-2 gross motor quotient, standardised scores and raw scores were used to describe proficiency.

RESULTS

GMS proficiency was assessed in n=259 3-6-year-old children (n=46 UH, n=91 UL, n=122 RL). Overall, 93% of the children were classified as having 'average' or better GMS. According to TGMD-2 standardised scores, the RL children performed significantly better than UH and UL children (p=0.028 and p=0.009, respectively). RL children were significantly more proficient than UH and UL children in the strike and horizontal jump when comparing raw scores. Overall, boys performed significantly better than girls in the strike, stationary dribble, kick and leap when comparing raw scores (all p<0.001).

CONCLUSIONS

This study reports high GMS proficiency in preschool-aged children across income settings in South Africa. The factors associated with higher GMS in low-income settings are not immediately obvious. Thus, future research should explore potential factors and identify opportunities to ensure that GMS proficiency is capitalised on as preschool-aged children enter formal schooling.

What is the impact of professional learning on physical activity interventions among preschool children? A systematic review

The purpose of this systematic review was to investigate professional learning models (length, mode, content) offered as part of objectively measured physical childcare-based interventions. A systematic review of eight electronic databases was conducted to June 2017. Only English, peer-reviewed studies that evaluated childcare-based physical activity interventions, incorporated professional learning and reported objectively measured physical activity were included. Study designs included randomized controlled trails, cluster randomized trials, experimental or pilot studies. The search identified 11 studies. Ten studies objectively measured physical activity using accelerometers; five studies used both accelerometer and direct observation tools and one study measured physical activity using direct observation only. Seven of these studies reported statistically significant intervention effects. Only six studies described all components of professional learning, but only two studies reported specific professional learning outcomes and physical activity outcomes. No patterns were identified between the length, mode and content of professional learning and children's physical activity outcomes in childcare settings. Educators play a critical role in modifying children's levels of physical activity in childcare settings. The findings of this review suggest that professional learning offered as part of a physical activity intervention that potentially impacts on children's physical activity outcomes remains under-reported.

A self-assembling luminescent lanthanide molecular nanoparticle with potential for live cell imaging

Four luminescent 32-metal Cd-Tb nanoclusters, [Tb₈Cd₂₄(L¹)₁₂(OAc)₄₈] (1), [Tb₈Cd₂₄(L²)₁₂(OAc)₄₈] (2), [Tb₈Cd₂₄(L³)₁₂(OAc)₄₈] (3) and [Tb₈Cd₂₄(L²)₁₂(1,4-BDC)₄(OAc)₃₈(OH)₂] (4), were constructed from three specially designed chain-like Schiff base ligands H₂L^1-3 with flexible carbon-carbon backbones containing 5, 6 and 10 methylene units, respectively. The clusters exhibit drum-like structures and can be imaged using transmission electron microscopy (TEM). In addition to the Schiff base ligands (the primary energy transfer donors), four 1,4-BDC bridging units were successfully introduced into the structure of 4. In addition to providing increased structural stability, the 1,4-BDC units act as secondary energy transfer donors providing extra energy for lanthanide luminescence, which results in improved luminescence properties when compared to those of the related Cd-Ln nanoclusters without 1,4-BDC units. In vitro investigations on 4 with SGC and PANC cancer cells revealed an accumulation of the molecular nanoparticles in the cells, as confirmed by confocal microscopy. The cytotoxicity of 4 toward the SGC and PANC cells is moderate (IC₅₀ values of 4 lie in the range of 15-60 μM). ICP-MS analysis reveals that cellular uptakes of 4 in 1000 SGC and PANC cells after treatment for 3 hours are 0.0094 pmol and 0.015 pmol, respectively.

Construction of luminescent high-nuclearity Zn–Ln rectangular nanoclusters with flexible long-chain Schiff base ligands

Two types of 8- and 14-metal Zn–Ln nanoclusters were prepared using long-chain Schiff base ligands and their interesting visible and NIR luminescence properties were investigated.

Apolipoprotein E4 inhibits autophagy gene products through direct, specific binding to CLEAR motifs

Introduction:

Alzheimer apolipoprotein E (APOE) ε4/ε4 carriers have earlier disease onset and more protein aggregates than patients with other APOE genotypes. Autophagy opposes aggregation, and important autophagy genes are coordinately regulated by transcription factor EB (TFEB) binding to “coordinated lysosomal expression and regulation” (CLEAR) DNA motifs.

Methods:

Autophagic gene expression was assessed in brains of controls and Alzheimer’s disease (AD) patients parsed by APOE genotype and in a glioblastoma cell line expressing either apoE3 or apoE4. Computational modeling assessed interactions between apoE and mutated apoE with CLEAR or modified DNA.

Results:

Three TFEB-regulated mRNA transcripts—SQSTM, MAP1LC3B, and LAMP2—were lower in AD ε4/ε4 than in AD ε3/ε3 brains. Computational modeling predicted avid specific binding of apoE4 to CLEAR motifs. ApoE was found in cellular nuclei, and in vitro binding assays suggest competition between apoE4 and TFEB at CLEAR sites.

Conclusion:

ApoE4-CLEAR interactions may account for suppressed autophagy in APOE ε4/ε4 carriers and, in this way, contribute to earlier AD onset.

Differences in Activation and Deactivation in Children with Sickle Cell Disease Compared with Demographically Matched Controls

BACKGROUND AND PURPOSE

Declines in both functional activation and functional connectivity have been reported in patients with sickle cell disease. In this study, we derived the functional and default mode responses to a word stem paradigm in age-, ethnicity-, and background-matched subjects with sickle cell disease and control groups, with the aim of testing whether both networks were similarly attenuated and whether the changes were related to physiologic parameters that characterize sickle cell disease.

MATERIALS AND METHODS

Both the functional and default mode responses were obtained from age- and background-matched controls and the sickle cell population by using a visually presented word stem paradigm on a 3T scanner.

RESULTS

We observed an attenuated response to both activation and deactivation in the sickle cell disease group. There were no significant differences in the activation response between the 2 groups for the contrast control > sickle cell disease; however, significant differences were observed in the medial parietal cortex, the auditory cortex, and the angular gyrus for the default mode. For the sickle cell group, a significant correlation between the activation z scores and the physiologic parameters was observed; for the deactivation, the results were not significant but the trend was similar.

CONCLUSIONS

The results indicate that the physiologic parameters modulate the activation in the expected fashion, but that the effect was weaker for deactivation. Given that significant differences between the 2 groups were only seen for deactivation, additional factors must modulate the deactivation in sickle cell disease.

Anion dependent self-assembly of sandwich 13-metal Ni-Ln nanoclusters with a long-chain Schiff base ligand

Two classes of Ni-Ln clusters [Ln₄Ni₃L₃(OAc)₆(NO₃)₃(OH)₃] (Ln = Gd (1) and Tb (2)) and [Ln₆Ni₇L₆(OAc)₁₂(OH)₆](OH)₂ (Ln = Gd (3) and Dy (4)) were prepared using a specifically designed Schiff base ligand built around a flexible (CH₂)₂O(CH₂)₂O(CH₂)₂ chain. 1 and 2 exhibit cone-like structures, while 3 and 4 have nanosized sandwich architectures. The structures were studied by single-crystal X-ray diffraction and TEM, and magnetic properties were investigated.

Effect of conjugation length and metal-backbone interactions on charge transport properties of conducting metallopolymers

Detailed studies on the effect of organic conjugation length, metal centers, and metal-backbone redox interactions on the charge transport properties of conducting metallopolymers (CMPs) are reported.

Negative feedback regulation of thyrotropin subunits and pituitary deiodinases in red drum, Sciaenops ocellatus

Thyroxine (T₄) undergoes dynamic daily cycles in the perciform fish the red drum, Sciaenops ocellatus, that are inversely timed to cycles of thyrotropin (TSH) subunit mRNA expression in the pituitary gland. We have proposed that these daily cycles are regulated by negative feedback of circulating T₄ on expression of pituitary thyroid hormone deiodinase type 3 (Dio3), such that elevated circulating T₄ results in diminished pituitary thyroid hormone catabolism and consequent increased negative feedback on expression of TSH subunits during the day. To determine whether thyroid hormones function to modulate expression of pituitary deiodinase enzymes we developed an immersion technique to administer physiological doses of T₃ and T₄in vivo. Immersion in T₄ or T₃ significantly inhibited the mRNA expression of the TSH α and β subunits from 4 to 66h of immersion. Pituitary Dio3 expression was significantly diminished by T₃ and T₄ at 22h. These results indicate that both T₄ and T₃ are capable of negative feedback regulation of TSH subunit expression in red drum at physiological concentrations and on a time scale consistent with the T₄ daily cycle. Furthermore, thyroid hormones negatively regulate Dio3 expression in the pituitary in a manner suggesting that negative thyroxine feedback on Dio3 promotes the release of TSH subunits from TH inhibition and may be an important mechanism for generating daily thyroid hormone cycles. These results highlight a potentially important role for D3 in mediating thyroid hormone feedback on TSH expression, not previously described in other species.

Single-component Eu3+–Tb3+–Gd3+-grafted polymer with ultra-high color rendering index white-light emission

Color-tuning to white-light (CIE coordinates of x = 0.322, y = 0.331; CCT of 5979 K; ultra-high CRI of 94) with a highly luminous efficiency (17.8%) was achieved for single-component Eu³⁺−Tb³⁺−Gd³⁺-grafted polymer Poly(MMA-co-2-co-3-co-4).

A Thiophene-Containing Conductive Metallopolymer Using an Fe(II) Bis(terpyridine) Core for Electrochromic Materials

Three Fe(II) bis(terpyridine)-based complexes with thiophene (Fe(L1)₂), bithiophene (Fe(L2)₂), and 3,4-ethylenedioxythiophene (Fe(L3)₂) side chains were designed and synthesized for the purpose of providing two terminal active sites for electrochemical polymerization. The corresponding metallopolymers (poly-Fe(Ln)₂, n = 2 or 3) were synthesized on indium tin oxide (ITO)-coated glass substrates via oxidative electropolymerization of the thiophene-substituted monomers and characterized using electrochemistry, X-ray photoelectron spectroscopy, UV-vis spectroscopy, and atomic force microscopy. The film poly-Fe(L2)₂ was further studied for electrochromic (EC) color-switching properties and fabricated into a solid-state EC device. Poly-Fe(L2)₂ films exhibit an intense MLCT absorption band at 596 nm (ε = 4.7 × 10⁴ M^-1 cm^-1) in the UV-vis spectra without any applied voltage. Upon application of low potentials (between 1.1 and 0.4 V vs Fc⁺/Fc), the obtained electropolymerized film exhibited great contrast with a change of transmittance percentage (ΔT%) of 40% and a high coloration efficiency of 3823 cm² C^-1 with a switching time of 1 s. The film demonstrates commonplace stability and reversibility with a 10% loss in peak current intensity after 200 cyclic voltammetry cycles and almost no loss in change of transmittance (ΔT%) after 900 potential switches between 1.1 and 0.4 V (vs Fc⁺/Fc) with a time interval of 0.75 s. The electropolymerization of Fe(L2)₂ provides convenient and controllable film fabrication. Electrochromic behavior was also achieved in a solid-state device composed of a poly-Fe(L2)₂ film and a polymer-supported electrolyte sandwiched between two ITO-coated glass electrodes.

Direct synthesis of CdSe nanocrystals within a conducting metallopolymer: toward improving charge transfer in hybrid nanomaterials

CdSe nanocrystals with tunable sizes and distributions were synthesized directly from Cd(ii) ions coordinated to the conjugated backbone of a thiophene-based conducting metallopolymer. Using our seeded growth technique, the resulting nanocrystals are in direct electronic communication with the polymer, which leads to effective charge transfer between the donor and acceptor.

Anisotropic lanthanide-based nano-clusters for imaging applications

We have developed a new class of lanthanide nano-clusters that self-assemble using flexible Schiff base ligands. Cd-Ln and Ni-Ln clusters, [Ln8Cd24(L1)12(OAc)39Cl7(OH)2] (Ln = Nd, Eu), [Eu8Cd24(L1)12(OAc)44], [Ln8Cd24(L2)12(OAc)44] (Ln = Nd, Yb, Sm) and [Nd2Ni4(L3)2(acac)6(NO3)2(OH)2], were constructed using different types of flexible Schiff base ligands. These molecular nano-clusters exhibit anisotropic architectures that differ considerably depending upon the presence of Cd (nano-drum) or Ni (square-like nano-cluster). Structural characterization of the self-assembled particles has been undertaken using crystallography, transmission electron microscopy and small-angle X-ray scattering. Comparison of the metric dimensions of the nano-drums shows a consistency of size using these techniques, suggesting that these molecules may share similar structural features in both solid and solution states. Photophysical properties were studied by excitation of the ligand-centered absorption bands in the solid state and in solution, and using confocal microscopy of microspheres loaded with the compounds. The emissive properties of these compounds vary depending upon the combination of lanthanide and Cd or Ni present in these clusters. The results provide new insights into the construction of novel high-nuclearity nano-clusters and offer a promising foundation for the development of new functional nanomaterials.

Self-assembly of high-nuclearity lanthanide-based nanoclusters for potential bioimaging applications

Two series of Cd-Ln and Ni-Ln clusters [Ln8Cd24L12(OAc)44(48)Cl4(0)] and [Ln8Ni6L6(OAc)24(EtOH)6(H2O)2] were constructed using a flexible ligand. The Cd-Ln clusters exhibit interesting nano-drum-like structures which allows direct visualization by TEM. Luminex MicroPlex Microspheres loaded with the Cd-Sm cluster were visualized using epifluorescence microscopy. Cytotoxicity studies on A549 and AGS cancer cell lines showed that the materials have mild to moderate cytotoxicity.