4R-cembranoid suppresses glial cells inflammatory phenotypes and prevents hippocampal neuronal loss in LPS-treated mice.

Chronic neuroinflammation has been implicated in neurodegenerative disease pathogenesis. A key feature of neuroinflammation is neuronal loss and glial activation, including microglia and astrocytes. 4R-cembranoid (4R) is a natural compound that inhibits hippocampal pro-inflammatory cytokines and increases memory function in mice. We used the lipopolysaccharide (LPS) injection model to study the effect of 4R on neuronal density and microglia and astrocyte activation. C57BL/6J wild-type mice were injected with LPS (5 mg/kg) and 2 h later received either 4R (6 mg/kg) or vehicle. Mice were sacrificed after 72 h for analysis of brain pathology. Confocal images of brain sections immunostained for microglial, astrocyte, and neuronal markers were used to quantify cellular hippocampal phenotypes and neurons. Hippocampal lysates were used to measure the expression levels of neuronal nuclear protein (NeuN), inducible nitrous oxide synthase (iNOS), arginase-1, thrombospondin-1 (THBS1), glial cell-derived neurotrophic factor (GDNF), and orosomucoid-2 (ORM2) by western blot. iNOS and arginase-1 are widely used protein markers of pro- and anti-inflammatory microglia, respectively. GDNF promotes neuronal survival, and ORM2 and THBS1 are astrocytic proteins that regulate synaptic plasticity and inhibit microglial activation. 4R administration significantly reduced neuronal loss and the number of pro-inflammatory microglia 72 h after LPS injection. It also decreased the expression of the pro-inflammatory protein iNOS while increasing arginase-1 expression, supporting its anti-inflammatory role. The protein expression of THBS1, GDNF, and ORM2 was increased by 4R. Our data show that 4R preserves the integrity of hippocampal neurons against LPS-induced neuroinflammation in mice.

Separation of diarylethene-based photoswitchable isomeric compounds by high-performance liquid chromatography and supercritical fluid chromatography.

Diarylethene-based photoswitches have become very popular over the last few decades for potential applications in chemistry, materials science, and biotechnology due to their unique physical and chemical properties. We report the isomeric separation of a diarylethene-based photoswitchable compound using high-performance liquid chromatography. The separated isomers were characterized by ultraviolet-visible spectroscopy and mass spectrometry confirmed the isomeric nature of the compounds. The isomers were purified by preparative high-performance liquid chromatography, providing fractionated samples to study the isomers individually. A total amount of 13 mg of an isomer of interest was fractionated from a solution of 0.4 mg/ml of the isomeric mixture. Because the preparative high-performance liquid chromatographic method required large quantities of solvent, we explored the use of supercritical fluid chromatography as an alternative separation mode which, to the best of our knowledge, is the first time this technique is used to separate diarylethene-based photoswitchable compounds. Supercritical fluid chromatography provided faster analysis times while maintaining sufficient baseline resolution for the separated compounds and consuming less organic solvent in the mobile phase compared to high-performance liquid chromatography. It is proposed that the supercritical fluid chromatographic method be upscaled and used in future fractionation of the diarylethene isomeric compounds, becoming a more environmentally benign approach for compound purification.

4R-cembranoid confers neuroprotection against LPS-induced hippocampal inflammation in mice.

BACKGROUND: Chronic brain inflammation has been implicated in the pathogenesis of various neurodegenerative diseases and disorders. For example, overexpression of pro-inflammatory cytokines has been associated with impairments in hippocampal-dependent memory. Lipopolysaccharide (LPS) injection is a widely used model to explore the pathobiology of inflammation. LPS injection into mice causes systemic inflammation, neuronal damage, and poor memory outcomes if the inflammation is not controlled. Activation of the alpha-7 nicotinic receptor (α7) plays an anti-inflammatory role in the brain through vagal efferent nerve signaling. 4R-cembranoid (4R) is a natural compound that crosses the blood-brain barrier, induces neuronal survival, and has been shown to modulate the activity of nicotinic receptors. The purpose of this study is to determine whether 4R reduces the deleterious effects of LPS-induced neuroinflammation and whether the α7 receptor plays a role in mediating these beneficial effects. METHODS: Ex vivo population spike recordings were performed in C57BL/6J wild-type (WT) and alpha-7-knockout (α7KO) mouse hippocampal slices in the presence of 4R and nicotinic receptor inhibitors. For in vivo studies, WT and α7KO mice were injected with LPS for 2 h, followed by 4R or vehicle for 22 h. Analyses of IL-1ß, TNF-α, STAT3, CREB, Akt1, and the long-term novel object recognition test (NORT) were performed for both genotypes. In addition, RNA sequencing and RT-qPCR analyses were carried out for 12 mRNAs related to neuroinflammation and their modification by 4R. RESULTS: 4R confers neuroprotection after NMDA-induced neurotoxicity in both WT and α7KO mice. Moreover, hippocampal TNF-α and IL-1ß levels were decreased with 4R treatment following LPS exposure in both strains of mice. 4R restored LPS-induced cognitive decline in NORT. There was a significant increase in the phosphorylation of STAT3, CREB, and Akt1 with 4R treatment in the WT mouse hippocampus following LPS exposure. In α7KO mice, only pAkt levels were significantly elevated in the cortex. 4R significantly upregulated mRNA levels of ORM2, GDNF, and C3 following LPS exposure. These proteins are known to play a role in modulating microglial activation, neuronal survival, and memory. CONCLUSION: Our results indicate that 4R decreases the levels of pro-inflammatory cytokines; improves memory function; activates STAT3, Akt1, and CREB phosphorylation; and upregulates the mRNA levels of ORM2, GDNF, and C3. These effects are independent of the α7 nicotinic receptor.

Evaluation of an amide-based stationary phase for supercritical fluid chromatography.

J. Sep. Sci. 2016, 39, 3469-3476 A stationary phase containing an amide group embedded in a hydrophobic backbone (i.e., C18-amide) attached to silica particles was characterized by means of the linear solvation energy relationship model, which relates the chromatographic retention factor to specific solute interactions. The evaluationwas conducted under supercritical fluid chromatographic conditions using a mobile phase composition of carbon dioxide and methanol as co-solvent. The stationary phase showed to provide an alternate separation selectivity that is attractive to separate drug-like polar compounds in a relatively fast analysis time.

Evaluation of an amide-based stationary phase for supercritical fluid chromatography.

A relatively new stationary phase containing a polar group embedded in a hydrophobic backbone (i.e., ACE®C18-amide) was evaluated for use in supercritical fluid chromatography. The amide-based column was compared with columns packed with bare silica, C18 silica, and a terminal-amide silica phase. The system was held at supercritical pressure and temperature with a mobile phase composition of CO2 and methanol as cosolvent. The linear solvation energy relationship model was used to evaluate the behavior of these stationary phases, relating the retention factor of selected probes to specific chromatographic interactions. A five-component test mixture, consisting of a group of drug-like molecules was separated isocratically. The results show that the C18 -amide stationary phase provided a combination of interactions contributing to the retention of the probe compounds. The hydrophobic interactions are favorable; however, the electron donating ability of the embedded amide group shows a large positive interaction. Under the chromatographic conditions used, the C18 -amide column was able to provide baseline resolution of all the drug-like probe compounds in a text mixture, while the other columns tested did not.

Fractionation of carbon-based nanomaterials by anion-exchange HPLC.

A sample containing carbon nanoparticles was obtained starting with the soot generated during combustion of inexpensive paraffin oil in a flame. The complexity of the sample, however, required fractionation to isolate its components. Anion-exchange high-performance liquid chromatography (AE-HPLC) was used for the analysis and collection of soot-derived carbon nanoparticles. The fractionated species were monitored by ultraviolet (UV) absorption and laser-induced photoluminescence detection, providing the chromatographic UV absorption and emission profiles of the separated sample. Chromatographic fractionation allowed for bulk measurements of electronic properties for individual fractions and further analysis via transmission electron microscopy (TEM). TEM of fractionated species showed a predominant size of about 4-5 nm diameter particulates. A general trend between photoluminescence and elution time was observed; the later eluting species in the chromatogram exhibited photoluminescence at longer wavelengths than the early eluting species. The AE-HPLC approach can have an immediate impact on the analysis and fractionation of various other nanomaterials, demonstrated here by analyzing samples containing graphitic oxide nanoparticles.

Study on the effects of humic and fulvic acids on quantum dot nanoparticles using capillary electrophoresis with laser-induced fluorescence detection.

The increasing production and use of quantum dot (QD) nanoparticles have caused concerns on the possibility of contaminating the aquatic and terrestrial ecosystems with wastes that may contain QDs. Therefore, studies on the behavior of QDs upon interaction with components of the natural environment have become of interest. This study investigated the fluorescence and electrophoretic mobility of carboxylic or amine polyethylene glycol (PEG)-functionalized CdSe/ZnS QDs in the presence of two aquatic humic substances (HS), Suwannee River humic and fulvic acids, using capillary electrophoresis with laser-induced fluorescence detection. Results showed initial enhancement in fluorescence of QDs at the onset of the interaction with HS, followed by fluorescence quenching at longer exposure with HS (>30 min). It was also observed that the electrophoretic mobility of QDs increases with increasing concentration of HS, suggesting an increase in the ratio in charge to hydrodynamic size of the nanoparticles. To determine if the QDs degraded upon interaction with HS, the QD-HS mixtures were dialyzed to separate free Cd2+ from intact QDs, followed by analysis of the solutions using inductively coupled plasma-mass spectrometry. Results suggested that degradation of QDs in the presence of HS did not occur within the period of incubation.

Intermolecular Interactions at the Silica-Liquid Interface Modulate the Fermi Resonance Coupling in Surface Methanol.

The buried solid/liquid interface between hydrophilic fused silica and binary solvent mixtures of acetonitrile (MeCN) and methanol (MeOH) was studied with vibrational sum-frequency generation (vSFG) spectroscopy. Our data showed that at high relative concentrations of methanol, the Fermi resonance peak in the vSFG spectrum is greatly suppressed, and it progressively gains intensity as methanol is diluted with perdeuterated acetonitrile. This phenomenon is quantified by the Fermi resonance coupling coefficient, W, extracted using a two-level model, as well as the experimental intensity ratio, R, of the methyl Fermi resonance band to that of the symmetric stretch. At a 1.0 MeOH mole fraction, W and R values were 10 ± 10 cm-1 and 0.01 ± 0.02, respectively, whereas at a 0.1 mole fraction, W and R increased to 46 ± 4 cm-1 and 0.43 ± 0.16, respectively. This indicates that solvation with acetonitrile effectively tunes the Fermi coupling of methanol vibrations at the silica/liquid interface.

Building a Networked Improvement Community: Lessons in Organizing to Promote Diversity, Equity, and Inclusion in Science, Technology, Engineering, and Mathematics.

In 2016, 10 universities launched a Networked Improvement Community (NIC) aimed at increasing the number of scholars from Alliances for Graduate Education and the Professoriate (AGEP) populations entering science, technology, engineering, and mathematics (STEM) faculty careers. NICs bring together stakeholders focused on a common goal to accelerate innovation through structured, ongoing intervention development, implementation, and refinement. We theorized a NIC organizational structure would aid understandings of a complex problem in different contexts and accelerate opportunities to develop and improve interventions to address the problem. A distinctive feature of this NIC is its diverse institutional composition of public and private, predominantly white institutions, a historically Black university, a Hispanic-serving institution, and land grant institutions located across eight states and Washington, DC, United States. NIC members hold different positions within their institutions and have access to varied levers of change. Among the many lessons learned through this community case study, analyzing and addressing failed strategies is as equally important to a healthy NIC as is sharing learning from successful interventions. We initially relied on pre-existing relationships and assumptions about how we would work together, rather than making explicit how the NIC would develop, establish norms, understand common processes, and manage changing relationships. We had varied understandings of the depth of campus differences, sometimes resulting in frustrations about the disparate progress on goals. NIC structures require significant engagement with the group, often more intensive than traditional multi-institution organizational structures. They require time to develop and ongoing maintenance in order to advance the work. We continue to reevaluate our model for leadership, climate, diversity, conflict resolution, engagement, decision-making, roles, and data, leading to increased investment in the success of all NIC institutions. Our NIC has evolved from the traditional NIC model to become the Center for the Integration of Research, Teaching and Learning (CIRTL) AGEP NIC model with five key characteristics: (1) A well-specified aim, (2) An understanding of systems, including a variety of contexts and different organizations, (3) A culture and practice of shared leadership and inclusivity, (4) The use of data reflecting different institutional contexts, and (5) The ability to accelerate infrastructure and interventions. We conclude with recommendations for those considering developing a NIC to promote diversity, equity, and inclusion efforts.

Physical characterization and evaluation of HPLC columns packed with superficially porous particles.

Two HPLC columns packed with superficially porous packing material (Kinetex™ 1.7 and 2.6 µm C18 particles) were evaluated in terms of their physical properties and performance characteristics. These columns were compared to a column packed with a sub-2 µm totally porous material and to a Halo(TM) column packed with 2.7 µm C18 superficially porous packing. The columns packed with superficially porous particles displayed a comparably narrower size distribution, which is narrower than the distribution of the totally porous sub-2 µm particles. Physical characteristics of the Kinetex™ particles were evaluated in terms of surface area, pore diameter, and specific pore volume. Total, external, internal, and shell porosities among the four different columns were evaluated and compared. The specific permeability for the Kinetex™ columns showed values close to those predicted by the Kozeny-Carman equation. All four columns were evaluated in terms of their chromatographic performance and compared using the Knox equation. The columns packed with the 2.6 and 2.7 µm superficially porous materials showed reduced plate heights below 2, whereas the sub-2 µm particles showed values of 2.2 and above.

Enrichment/isolation of phosphorylated peptides on hafnium oxide prior to mass spectrometric analysis.

Hafnium oxide (hafnia) exhibits unique enrichment properties towards phosphorylated peptides that are complementary to those of titanium oxide (titania) and zirconium oxide (zirconia) for use with mass spectrometric analysis in the field of proteomics.

Hydrosilylated allyl-silica hybrid monolithic columns.

Organic-inorganic silica hybrid monolithic columns were synthesized containing an allyl pendant. The ally-monolithic columns were then modified via hydrosilylation reactions to introduce further surface functionalization. The approach was demonstrated by functionalizing allyl-monolytic columns with n-octyl-dimethylsilane (C(8)-DMS) and benzyl-dimethylsilane (benzyl-DMS). Of the surface available ally groups on the hybrid monolith (i.e., 6.79 micromol/m(2)), 31.3% reacted via hydrosilylation, resulting in a C(8) surface coverage of 2.12 micromol/m(2). When using benzyl-DMS, a surface coverage of 1.95 micromol/m(2) was calculated for the benzyl groups. The retentivity of the hybrid monolithic columns increased considerably after the hydrosilylation, as monitored by CLC and CEC. The largest increase in retention was observed with the C(8) modified monolith. The hybrid monolithic columns showed higher hydrolytic stability than monolithic columns prepared by the conventional silanoxane bonding of alkyl chlorosilanes modification. The ally-monolithic column provides a platform for the fabrication of hybrid monoliths that can be conveniently modified by means of hydrosilylation, tailoring the surface of the material. The approach is a promising method to prepare hybrid monolithic columns with versatile stationary phases in a simple and efficient manner.

Fused-core, sub-2 microm packings, and monolithic HPLC columns: a comparative evaluation.

Three different HPLC column technologies (i.e., monolith, fused-core particles, and sub-2 microm particles) were evaluated, comparing van Deemter plots, speed of analysis, back pressure, and mobile phase consumption. Very high linear velocities (approximately 12 mm/s) were achieved with the monolithic column using modest pressure (110 bar) at the expense of high mobile phase consumption. The minimum plate height of the monolith was similar to that of a 3 microm-particle packed column (i.e., h = 8 microm), operated at optimal linear velocities; the monolithic column showed substantially lower mass transfer dependence, however. The 2.7 microm fused-core packing material yielded efficiencies closer to the sub-2 microm material than to the 3 microm-particle packed column and could be operated at high flow rates. The fused-core column was able to achieve linear velocities similar to those attained on the sub-2 microm column, staying below 620 bar instead of almost near 1030 bar required by the sub-2 microm material. The lack of pH stability of the monolithic column prevented its use to separate basic compounds (i.e., tricyclic antidepressants) at high pH. Best separation of these components at high pH was achieved using the column packed with 1.7 microm hybrid material.

Determination of lopinavir cerebral spinal fluid and plasma ultrafiltrate concentrations by liquid chromatography coupled to tandem mass spectrometry.

A method for the determination of lopinavir (LPV) concentrations in cerebral spinal fluid (CSF) and plasma ultrafiltrate (UF) was developed and validated to analyze clinical specimens from patients receiving antiretroviral treatment with lopinavir/ritonavir. The CSF (400 microL sample volume) final calibration range for LPV was 0.313-25.0 ng/mL. The final calibration range for UF (50 microL sample volume) was 1.25-100 ng/mL. The samples were prepared using liquid-liquid extraction, concentrated, and analyzed using a reversed phase isocratic separation. Detection was achieved in positive mixed reaction monitoring mode on a triple quadrupole mass spectrometer. Isolation of LPV through chromatographic separation and proper selection of calibration matrix were important factors in achieving accurate results. Plasma UF was found to be an equivalent calibration matrix to CSF whereas plasma matrix produced a positive bias in samples with unknown concentrations. Artificial CSF media prepared chemically were biased and less superior than UF. Sources of plasma for the UF did not affect accuracy. Several CSF sources were tested for specificity of the method and LPV concentrations were accurately produced with atmospheric pressure chemical ionization source producing more accurate results than the electrospray source. The method successfully measured LPV concentrations in CSF that were previously undetectable by HPLC as well as UF from protein binding studies.

Very high-pressure capillary liquid chromatography assisted by voltage.

Capillary liquid chromatography at moderately high pressures and capillary electrochromatography (CEC) have been combined to drive the mobile phase through capillary columns packed with small diameter particles. In a column packed with 1.5 microm nonporous particles, linear velocities near 3mm/s were observed when combining inlet pressures of 690 bar (10,000 psi) and an applied voltage of 25 kV. Optimum linear velocity for the column was achieved using a pressure-voltage combination of 350 bar (5000 psi) and 5 kV. Separation efficiencies at near optimum linear velocity agreed with those predicted by the van Deemter equation for liquid chromatography. Retention factors were observed to decrease under pressure-voltage combination as the voltage was increased; such a behavior has been attributed to Joule heating effects.

Nanodiamond-Decorated Silica Spheres as a Chromatographic Material.

Nanodiamond (ND) particles (∼5 nm), obtained from detonation soot, were oxidized and/or thermally hydrogenated. Both, the non-hydrogenated and hydrogenated ND particles were successfully coupled to the surface of micrometer-size organo-silica particles. A thin layer of nanodiamonds (NDs) decorating the surface of the organo-silica particles was visible on transmission electron microscopy (TEM) images. X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR) were used to characterize the NDs prior to coupling and to confirm attachment onto the organo-silica particles. Both, ultraviolet (UV) radiation and a chemical initiator were proved to be effective radical initiators for the ND-silica coupling reaction, although for scale-up purposes the chemical initiation was more advantageous to produce the ND-silica composite. Commercially available nanodiamond primary particles were also coupled to the surface of silica particles. The ND-containing silica particles were packed into chromatographic columns to study their initial feasibility as adsorbent material for liquid chromatography. The organo-silica particles decorated with hydrogenated NDs were shown to possess reversed phase type (i.e., hydrophobic) behavior toward the probe compounds, whereas silica particles decorated with the non-hydrogenated NDs showed polar (i.e., hydrophilic) interactions, both under liquid chromatographic conditions.

Evaluation of lacrimal fluid as an alternative for monitoring glucose in critically ill patients.

OBJECTIVE: This study evaluated the use of lacrimal fluid glucose concentrations as a minimally invasive, alternative sampling strategy for monitoring glucose concentrations in surgical/trauma ICU patients. DESIGN AND SETTING: Prospective, paired sample study in an adult surgical/trauma ICU. PATIENTS: Patients receiving subcutaneous or intravenous insulin requiring routine capillary blood glucose measurements. Patients receiving ocular lubricants, artificial tears, or routinely administered ophthalmic medications and patients with facial injuries were excluded. INTERVENTIONS: Lacrimal fluid was collected using glass capillary tube placed near the cul-de-sac of the eye. Capillary blood glucose was determined using a bedside glucose meter as per routine ICU care. MEASUREMENTS AND RESULTS: Lacrimal fluid glucose concentration was analyzed using high-performance liquid chromatography with pulse amperometric detection. Forty-four paired samples from five patients were analyzed. Pearson correlation between lacrimal fluid (microM) and blood glucose (mM) concentrations and the proportional change from baseline revealed no significant associations. Due to the very poor association, enrollment was discontinued after five patients. CONCLUSIONS: Lacrimal fluid and blood glucose concentrations were poorly correlated, suggesting that the former is not a reliable alternative to blood glucose monitoring in surgical/trauma ICU patients requiring insulin therapy.

Allyl-functionalized hybrid silica monoliths.

A hybrid organosilica monolith was synthesized containing an allyl functionality. This provided a viable platform for producing silica-based, chromatographic, monolithic columns with the stationary phase bonded through a surface silicon-carbon bond rather than a conventional siloxane bond.