Broad Signal Research Articles

Operando Observations of Reversible α-BiF3 Conversion in Liquid Electrolyte by Synchrotron Radiation Diffraction and 7Li Nuclear Magnetic Resonance

The electrochemically-driven conversion reaction of BiF3 with Li+ ions is of interest for potential application as a positive electrode system in conversion type rechargeable batteries. Here, we use synchrotron radiation diffraction and 7Li nuclear magnetic resonance (NMR) for complementary operando observations of reversible or quasi-reversible conversion reactions of α-BiF3 nanocomposite electrode at room temperature. The nanocomposite electrode was fabricated by ball milling and subsequent heat treatments. A pronounced XRD peak broadening indicated a disordered fine crystalline state in the electrode. The operando synchrotron radiation diffraction measurements revealed a quasi-reversible smooth crystallographic transformation between α-BiF3 and metallic Bi. The operando 7Li NMR measurement quantitatively showed reversible conversion reactions. The series of in-situ 7Li NMR spectra contained sharp signals from Li+ ions in the electrolyte and a broad signal associated with a solid phase of LiF. These signals followed a stoichiometric relationship that conformed to a three-electron BiF3 conversion pathway.

Air, water, soil and environmental signaling

Within a remarkably short timespan the world population doubled and transitioned from an agrarian to an urban-industrial society. The transition was accompanied by the major expansion of industries that releases enormous amounts of toxicants into the air, water, and soil. Naturally occurring and synthetic chemicals compounds utilized the same signaling system as vertebrate internal cell signaling systems. The concept of environmental signals provides insights to address the impact of biochemically active toxicants on humans and the ecosystems that they share with other species. Disruption of the broad signaling systems has the potential for global change that transcends the biological systems of all organisms, including humans.

Copper(II) Hydrazone Complexes with Different Nuclearities and Geometries: Synthesis, Structural Characterization, Antioxidant Sod Activity and Antiproliferative Properties

New copper(II) hydrazone complexes with (Z)-2-(phenyl(2-(pyridin-2-yl)hydrazono)methyl)pyridine (L) were synthesized and characterized using various physicochemical methods. The geometry of complexes can be classified as mononuclear and binuclear. The complex 1 [Cu(L)Cl2] is mononuclear whereas solid-state structures of complex 2 contains a mixture of co-crystals of mono- and binuclear complexes 2a [Cu(L)(H2O)(SO4)] and 2b [(L)Cu-(SO4)2-Cu(L)]. The molecular structure of 2 contains two units of mononuclear complex 2a and two units of binuclear complex 2b. Copper contains in all mono- and binuclear complexes are in a distorted square pyramidal geometry. The present study indicates that complexes having different nuclearities and geometries can be achieved by changing synthetic conditions and methods. Variable temperature magnetic susceptibility measurements of the complexes have shown a weak anti-ferromagnetic interaction. The presence of weak anti-ferromagnetic interactions is mediated by intermolecular hydrogen bonding in 1 and by symmetric sulfate bridge in 2, respectively. The Epr spectra in polycrystalline state of 1 and 2 exhibited a broad signal at 2.149 due to the spin-spin interactions between two copper(II) ions. The cyclic voltammograms of complexes 1 and 2 in DMSO gave two irreversible redox waves. Density functional theory (DFT) calculations were evaluated in the study involved the molecular specification for the use of B3LYP/LANL2DZ formalism for copper atom and B3LYP/6-31G for the remaining atoms. Both complexes catalyzed the dismutation of superoxide ( 02). Furthermore, copper complexes and ligand were tested to explore the anticancer properties. Promising cytotoxicity of synthesized compounds was observed on the selected cancerous cell line of neuroblastoma, lung carcinoma, hepatocellular carcinoma and breast cancer.

Quantitative measures of myo-IP6 in soil using solution 31P NMR spectroscopy and spectral deconvolution fitting including a broad signal.

Inositol phosphates, particularly myo-inositol hexakisphosphate (myo-IP6), are an important pool of soil organic phosphorus (P) in terrestrial ecosystems. To measure concentrations of myo-IP6 in alkaline soil extracts, solution 31P nuclear magnetic resonance (NMR) spectroscopy is commonly used. However, overlap of the NMR peaks of myo-IP6 with several other peaks in the phosphomonoester region requires spectral deconvolution fitting (SDF) to partition the signals and quantify myo-IP6. At present, two main SDF approaches are in use; the first fits a Lorentzian/Gaussian lineshape to the myo-IP6 peaks directly to the baseline without an underlying broad signal, and the second fits a Lorentzian/Gaussian lineshape to the myo-IP6 peaks simultaneously with an underlying broad peak. The aim of this study was to compare the recovery of added myo-IP6 to soil extracts using both SDF procedures for six soil samples of diverse origin and differing concentrations of organic P (112 to 1505 mg P per kgsoil). The average recovery of total added myo-IP6 was 95% (SD 5) and 122% (SD 32) using SDF with and without an underlying broad signal, respectively. The recovery of individual peaks of myo-IP6 differed, most notably, the C5 phosphate peak of myo-IP6 was overestimated by up to 213% when a broad peak was not included in SDF. Based on the SDF procedure that includes a broad peak, concentrations of myo-IP6 ranged from 0.6 to 90.4 mg P per kgsoil, which comprised 1-23% of total phosphomonoesters. Our results demonstrate that the SDF procedure with an underlying broad signal is essential for the accurate quantification of myo-IP6 in soil extracts.

Suppression of parasitic lasing and inter-pulse self-pulsing in a pulsed Erbium–Ytterbium co-doped fiber amplifier

Performance of an Erbium–Ytterbium co-doped fiber (Nufern PM EYDF 12/130) has been investigated as a power amplifier stage for developing a pulsed, high peak power, 1550 nm laser with 30 ns pulse duration at 10 kHz repetition rate. A directly modulated, broadband, Fabry–Perot laser diode has been employed as seed laser in all fiber master oscillator power amplifier (MOPA) configuration. Amplifier performance was significantly improved by improving the spectral quality of seed and preamplifiers using two band-pass filters in tandem. This may be attributed to the reduction in inter-pulse Amplified Spontaneous Emission (ASE) noise. Comparative results have been presented for two different MOPA configurations. MOPA with broader signal spectrum resulted in Yb parasitic lasing at 5 W pump power causing roll over in the output energy. Also, onset of strong self-pulsing was observed during off period (in absence of signal pulse) at ~ 6.3 W input. Nature of these pulses resembled relaxation oscillations. Theoretically calculated time period (10–12 µs) of the self-pulses at various pump powers matched fairly well with the experimental results. However, with improved signal spectral quality, no such inter-pulse self-pulsing and parasitic lasing was observed up to 12 W pump power. More than 75 µJ energy per pulse was achieved, limited by power-handling capability of the output isolator. We present here several novel experimental results in terms of spectral, temporal and energy output for a pulsed EYDF amplifier generating 2.5 kW pulses @ 1550 nm.

MANAJEMEN WIRELESS DENGAN MAPPING SSID ACCESS POINT PADA STMIK LOMBOK

The wireless network at STMIK Lombok is connected to the local server network and the internet with the spread of access points in several buildings. In some parts of the building have different strengths and the access point or wireless signal strengths, some have broad and strong signal coverage, but there are also areas that have limited / weak signal coverage, even no wireless or blank-spot signal. This blank spot can be caused by many obstacles, including walls, tiles, trees, and others.
 Based on observations at STMIK Lombok, wireless signal coverage has not been able to cover the entire campus building area; many are unstable and tend to be weak. Therefore, wireless management research was conducted by mapping the SSID access point which is expected to offer/give a solution so that the wireless signal can cover all STMIK Lombok campus buildings.
 Wireless management by mapping SSID access points on STMIK Lombok provides a solution for location placement and number of access points to be installed so that the campus area of ​​STMIK Lombok can be covered by wireless networks.
 Keywords : wireless, wireless network, mapping SSID, access point, MikroTik

Guest Inclusion Modulates Concentration and Persistence of Photogenerated Radicals in Assembled Triphenylamine Macrocycles.

Substituted triphenylamine (TPA) radical cations show great potential as oxidants and as spin-containing units in polymer magnets. Their properties can be further tuned by supramolecular assembly. Here, we examine how the properties of photogenerated radical cations, intrinsic to TPA macrocycles, are altered upon their self-assembly into one-dimensional columns. These macrocycles consist of two TPAs and two methylene ureas, which drive the assembly into porous organic materials. Advantageously, upon activation the crystals can undergo guest exchange in a single-crystal-to-single-crystal transformation generating a series of isoskeletal host-guest complexes whose properties can be directly compared. Photoinduced electron transfer, initiated using 365 nm light-emitting diodes, affords radicals at room temperature as observed by electron paramagnetic resonance (EPR) spectroscopy. The line shape of the EPR spectra and the quantity of radicals can be modulated by both polarity and heavy atom inclusion of the encapsulated guest. These photogenerated radicals are persistent, with half-lives between 1 and 7 d and display no degradation upon radical decay. Re-irradiation of the samples can restore the radical concentration back to a similar maximum concentration, a feature that is reproducible over several cycles. EPR simulations of a representative spectrum indicate two species, one containing two N hyperfine interactions and an additional broad signal with no resolvable hyperfine interaction. Intriguingly, TPA analogues without bromine substitution also exhibit similar quantities of photogenerated radicals, suggesting that supramolecular strategies can enable more flexibility in stable TPA radical structures. These studies will help guide the development of new photoactive materials.

R2‐P2 rapid‐robotic phosphoproteomics enables multidimensional cell signaling studies

Recent developments in proteomics have enabled signaling studies where > 10,000 phosphosites can be routinely identified and quantified. Yet, current analyses are limited in throughput, reproducibility, and robustness, hampering experiments that involve multiple perturbations, such as those needed to map kinase–substrate relationships, capture pathway crosstalks, and network inference analysis. To address these challenges, we introduce rapid‐robotic phosphoproteomics (R2‐P2), an end‐to‐end automated method that uses magnetic particles to process protein extracts to deliver mass spectrometry‐ready phosphopeptides. R2‐P2 is rapid, robust, versatile, and high‐throughput. To showcase the method, we applied it, in combination with data‐independent acquisition mass spectrometry, to study signaling dynamics in the mitogen‐activated protein kinase (MAPK) pathway in yeast. Our results reveal broad and specific signaling events along the mating, the high‐osmolarity glycerol, and the invasive growth branches of the MAPK pathway, with robust phosphorylation of downstream regulatory proteins and transcription factors. Our method facilitates large‐scale signaling studies involving hundreds of perturbations opening the door to systems‐level studies aiming to capture signaling complexity.

Chitosan from marine-derived Penicillum spinulosum MH2 cell wall with special emphasis on its antimicrobial and antifouling properties

A fully identified marine-derived Penicillum spinulosum MH2 was isolated from the Eastern Harbor, Egypt. Data confirmed that PDB exhibited the highest fungal biomass 8.31 g/L after 15 days of incubation. The SEM photographs of prepared chitosan showed thick and rough surface morphology. The absorption bands of the extracted chitosan detected by FTIR were identical to those of the standard one. The 1H NMR spectrum of extracted chitosan showed two sets of singlet peaks at 2.46–2.99 and 2.64–2.67 ppm, which were assigned to the (H-2) protons of different chemical environments as in the structure of chitosan; one adjacent to the primary amine (2.46–2.99 ppm) and the other adjacent to acetyl group (2.64–2.67 ppm). The spectrum also showed broad signal of overlapped multiplets peaks (3.05–3.83) ppm, which correspond to the protons (H-3, H-4, H-5, and H-6). In addition, the results supported the extracted chitosan efficacy as antimicrobial agent against several microbes (S. aureus, B. subtilis, F. solani, R. solani, P. nutatum, and C. albicans). Moreover, it exhibited considerable antifouling activity against fouling bacteria.

Structure and optical properties of the photosensitive hybrid Ti-contained polymer materials for photonics

Titanium-containing interpenetrating polymer networks (Ti-IPNs) based on the cross-linked polyurethane, poly (hydroxyethyl methacrylate) and poly (titanium oxide) have been synthesized. First poly (titanium oxide) was synthesized by sol-gel method in the presence of 2-hydroxyethyl methacrylate at different molar ratio of Ti (OPri)4/H2O. The results obtained by method of optical spectrophotometry shows that the light transmission coefficients (T, %) of titanium-containing interpenetrating polymer networks samples was 90.7–91.0% at λ = 650 nm. According to EPR data, UV irradiation in the air at room temperature of Ti-IPN samples is accompanied by appearance of signal of paramagnetic centers with broad isotropic signal at g1 = 2.010 and also noticeably splitted signal at g2 = 2.003 and g3 = 1.967. First and second of them can be ascribed to the oxygen-containing “hole scavenger”, while the third one is associated with the Ti3+ paramagnetic ions. The low rate of the electron–hole pair recombination at room temperature in the air demonstrates efficient separation of the charged particles in the hybrid material. X-ray diffraction analysis indicates that Ti-IPN sample have an amorphous structure. UV-induced charge separation and subsequent charge recombination in Ti-IPNs cause the changes in short-range order in the arrangement of polymer macrochains.

CG-806, a First-in-Class Pan-FLT3/Pan-BTK Inhibitor, Exhibits Broad Signaling Inhibition in Chronic Lymphocytic Leukemia Cells

CG-806, a First-in-Class Pan-FLT3/Pan-BTK Inhibitor, Exhibits Broad Signaling Inhibition in Chronic Lymphocytic Leukemia Cells

Soil phosphorus pools with addition of fertiliser phosphorus in a long-term grazing experiment

Grasslands are a globally important use of land for food and fibre production, which often require the addition of phosphorus (P) fertiliser to maximise plant production. However, a large proportion of the added P can accumulate in pools of poorly available inorganic and organic P in the surface soil layer under grasslands. The aim of this study was to identify the chemical nature of the organic P in soils from a long-term fertiliser by grazing permanent pasture experiment that have received varying additions of phosphatic fertiliser (cumulative P input of 27, 169, 311, 513, 745 and 1035 kg P ha−1) over a period of 37 years. The design of the experiment uniquely provides insight into the response of soil organic P to the addition of fertiliser P on the decadal scale. On average, 46% of the added fertiliser P was recovered as total P in the 0–100 mm soil layer after 37 years of phosphate addition. The content of both inorganic and organic forms of soil P increased with the addition of fertiliser P. The accumulation of organic P increased linearly up to a cumulative P input of 745 kg P ha−1 and plateaued thereafter. The majority of organic P in all treatments was detected as a broad signal in the phosphomonoester region of solution 31P nuclear magnetic resonance (NMR) spectra; this also accounted for 79% of the accumulated organic P in fertilised soil. Our results indicate that accumulation of P in the organic portion as complex forms eventually reaches a new equilibrium where no net accumulation would be expected with further addition of phosphate.

A Phase-Canceled Backing Layer for Ultrasound Linear Array Transducer: Modeling and Experimental Verification.

In this study, a phase-canceled backing layer for ultrasound linear array transducer is presented. The proposed backing layer is composed of multiple blocks operated by a phase inversion technique. Inside the proposed backing layer, the phase of the reflected signals can be canceled by adjusting acoustic impedance, piezoelectric layer contact area, and thickness of each block constituting the backing layer. Therefore, the total thickness of the backing layer can be significantly reduced while maintaining the performance. Using finite element analysis (FEA) simulation, its performance was verified based on an 8-MHz linear array transducer. Two types of bulk-type backing layers with different thicknesses were also simulated to compare the performance of the proposed method. In the case of a narrow bandwidth signal without the matching layers, the 10-mm-thick bulk-type backing layer yielded a -6-dB bandwidth of 37.2%. When its thickness was reduced to 2 mm, the -6-dB bandwidth was decreased to 17.3% due to the reflected back-wall signals. However, the -6-dB bandwidth of the proposed backing layer with 2-mm thickness was 39.5%, which is similar to the thick bulk-type backing layer. In the case of broad bandwidth signal with the matching layers, the proposed transducer also exhibits similar performance compared with the thick bulk-type backing layer. The narrow bandwidth signal was experimentally implemented by using a prototype array transducer with the proposed technique, and the performance was similar to the simulation. Thus, the proposed method can reduce the thickness of the backing layer of various array transducers.

Growth and optical properties of GaPN/GaP heterostructure nanowire array

The study is devoted to synthesis and investigation of the optical properties of GaPN/GaP nanowire (NW) arrays grown on Si substrate (111) with plasma-assisted molecular beam epitaxy (PA-MBE). First, we demonstrate the growth of axial GaPN/GaP and GaP NW heterostructures. The morphology of GaP and GaPN/GaP NW arrays was investigated with scanning electron microscopy (SEM) to show that at low growth fluxes of activated nitrogen self-catalytic growth regime and nanowires morphology are preserved. Raman spectroscopy was used for investigation of phonon spectra features. Optical properties of the GaPN NW arrays were determined at room temperature with photoluminescence (PL) spectroscopy. Analysis of both Raman spectroscopy and PL results allowed to analyze the GaPN/GaP NWs chemical composition. Dilution of GaP NWs with N allows to significantly increase PL intensity and obtain broad PL signal in the optical spectral region demonstrating the potential of GaPN NWs for future nano-optoelectronics and photonics.

The human cytomegalovirus-encoded G protein–coupled receptor UL33 exhibits oncomodulatory properties

Herpesviruses can rewire cellular signaling in host cells by expressing viral G protein-coupled receptors (GPCRs). These viral receptors exhibit homology to human chemokine receptors, but some display constitutive activity and promiscuous G protein coupling. Human cytomegalovirus (HCMV) has been detected in multiple cancers, including glioblastoma, and its genome encodes four GPCRs. One of these receptors, US28, is expressed in glioblastoma and possesses constitutive activity and oncomodulatory properties. UL33, another HCMV-encoded GPCR, also displays constitutive signaling via Gαq, Gαi, and Gαs proteins. However, little is known about the nature and functional effects of UL33-driven signaling. Here, we assessed UL33's signaling repertoire and oncomodulatory potential. UL33 activated multiple proliferative, angiogenic, and inflammatory signaling pathways in HEK293T and U251 glioblastoma cells. Notably, upon infection, UL33 contributed to HCMV-mediated STAT3 activation. Moreover, UL33 increased spheroid growth in vitro and accelerated tumor growth in different in vivo tumor models, including an orthotopic glioblastoma xenograft model. UL33-mediated signaling was similar to that stimulated by US28; however, UL33-induced tumor growth was delayed. Additionally, the spatiotemporal expression of the two receptors only partially overlapped in HCMV-infected glioblastoma cells. In conclusion, our results unveil that UL33 has broad signaling capacity and provide mechanistic insight into its functional effects. UL33, like US28, exhibits oncomodulatory properties, elicited via constitutive activation of multiple signaling pathways. UL33 and US28 might contribute to HCMV's oncomodulatory effects through complementing and converging cellular signaling, and hence UL33 may represent a promising drug target in HCMV-associated malignancies.

Description of Steam Cracker Fouling and Coking Residues by Thermal Analysis-Photoionization Mass Spectrometry

Two organic fouling samples obtained from downstream the cracking oven (DS) and from upstream the hot zone (US) of a steam cracker facility were characterized. For this purpose, a simultaneous thermal analyzer coupled to a photoionization mass spectrometer (STA-PI-MS) and a thermal desorption/pyrolysis gas chromatograph (TD/Py-GC-EI-MS) were used. Mass loss and differential scanning calorimetry information revealed the degradation of the materials beginning at 130 °C with two distinct maxima for US and one for DS (230–330 °C) as well as broad signals (330–500 °C) for both. Structural motives of different polymeric-like structures were assigned based on PI-MS of the effluent and separately conducted TD/Py-GC-EI-MS. The advantage of soft photoionization over hard ionization techniques such as electron ionization is the considerable reduction of fragmentation, yielding higher abundancies of molecular ions. Thus, even though complex samples are studied, evolving constituents can often be easily tracked in a time-resolved manner (1 Hz). While single photon ionization (SPI, 118 nm = 10.5 eV) ionizes most organic molecules, resonance-enhanced multiphoton ionization (REMPI, 2 × 266 nm = 9.4 eV) selectively addresses aromatic species. Differentiation of polymeric-like structures was achieved by exploiting this selectivity (SPI vs REMPI) and comparison of molecular patterns with GC-EI-MS data, which supports the identification of compounds by providing fragmentation patterns and chemical information based on retention time. US shows high inorganic content (∼50%) and more diversity in its organic part, as indicated by four types of patterns: polyethylene-like, Diels–Alder-like, polythioether/polysulfide-like, and polystyrene-like motives. In contrast, DS exhibits almost only signals of Diels–Alder-like and polystyrene-like structures and contains a less inorganic material (∼23%). Additionally, first attempts to quantify the Diels–Alder content by STA-SPI-MS were successfully conducted.

Dispersion of Graphene in an Aqueous Solution with Poly(sodium 4-styrenesulfonate) Monitored by Capillary Electrophoresis

Graphene was dispersed in an aqueous solution with poly(sodium 4-styrenesulfonate) as a dispersant. The charge of the graphene came to be apparently negative by the adsorption of poly(4-styrenesulfonate) ion (PSS). Two kinds of PSS were examined: the average molecular masses of 70,000 and 1,000,000 (PSS 70,000 and PSS 1,000,000, respectively). Capillary electrophoresis was used to evaluate the dispersion of the apparently anionic graphene in an aqueous solution. A broad signal corresponding to the dispersed graphene was detected in the electropherograms. The effective electrophoretic mobility of the dispersed graphene was somewhat larger at higher concentrations of PSS 70,000, suggesting that the adsorbed amount of PSS 70,000 increased. Even when the separation buffer did not contain PSS, the broad signal of the anionic graphene was still detected. The peak height and/or the peak area, as well as the effective electrophoretic mobility of the graphene decreased little at the reduced applied voltages, i.e., at longer separation/detection time. Therefore, the adsorption of PSS is irreversible or the desorption of PSS from the graphene surface is very slow. Accordingly, the dispersed graphene with PSS would be separated from the matrix PSS by the electrophoretic separation.

Unmanned Aerial Vehicles (UAVs) for Monitoring Macroalgal Biodiversity: Comparison of RGB and Multispectral Imaging Sensors for Biodiversity Assessments

Developments in the capabilities and affordability of unmanned aerial vehicles (UAVs) have led to an explosion in their use for a range of ecological and agricultural remote sensing applications. However, the ubiquity of visible light cameras aboard readily available UAVs may be limiting the application of these devices for fine-scale, high taxonomic resolution monitoring. Here we compare the use of RGB and multispectral cameras deployed aboard UAVs for assessing intertidal and shallow subtidal marine macroalgae to a high taxonomic resolution. Our results show that the diverse spectral profiles of marine macroalgae naturally lend themselves to remote sensing and habitat classification. Furthermore, we show that biodiversity assessments, particularly in shallow subtidal habitats, are enhanced using six-band discrete wavelength multispectral sensors (81% accuracy, Cohen’s Kappa) compared to three-band broad channel RGB sensors (79% accuracy, Cohen’s Kappa) for 10 habitat classes. Combining broad band RGB signals and narrow band multispectral sensing further improved the accuracy of classification with a combined accuracy of 90% (Cohen’s Kappa). Despite notable improvements in accuracy with multispectral imaging, RGB sensors were highly capable of broad habitat classification and rivaled multispectral sensors for classifying intertidal habitats. High spatial scale monitoring of turbid exposed rocky reefs presents a unique set of challenges, but the limitations of more traditional methods can be overcome by targeting ideal conditions with UAVs.

Targeting bone marrow adipose tissue and the FABP family increases efficacy of dexamethasone in MM

It is well known that multiple myeloma (MM) cells have a dependency on the bone marrow (BM) microenvironment for survival and proliferation. Targeting stromal cells of the BM, rather than just the tumor cells themselves, can be useful for reducing tumor burden in mice and humans. Our lab has recently explored targeting the bone marrow adipocyte (BMA) due to correlations between obesity to increased risk of MM and increased BM adiposity. To test the effects of BMAs on MM1S in vivo, 5-week old SCID-beige female mice were treated with saline or an anti-sclerostin antibody (Scl-Ab, 100 mg/kg once per week IP) for 5 weeks (a treatment shown to increase bone volume and decrease BMAs). Then, 5x10ˆ6 human GFP+luc+MM1S cells were injected i.v. followed by 5 additional weeks of Scl-Ab or saline treatments. Mice were treated with or without dexamethasone (dex) (9mg/kg IP) during weeks 4-6 after MM1S injection. Mice were assessed with biweekly whole body bioluminescent imaging (BLI) and survival. Dex treatments led to a significantly lower total flux BLI signal (p<0.05 vs MM1S alone), and Scl-Ab+dex combination treatments had the least total flux BLI signal (p<0.01 vs MM1S alone) at day 33. Interestingly, Scl-Ab+dex combination treatments increased mouse survival significantly versus dex alone, Scl-Ab treatment alone, or no treatment. Thus, our in vivo data suggested that decreasing bone marrow adiposity enhanced anti-myeloma effects of dex. Next, to specifically examine the effects of BMAs on myeloma cells, we generated human BMAs from BM mesenchymal stem cells with adipogenic media. MM1S cells were cultured in conditioned media from BMAs (BMA-CM); BMA-CM from many, but not all donors, supported MM1S proliferation, migration, or drug resistance. Specifically, some BMAs protected MM1S cells against dex-induced apoptosis, assessed by Annexin V/DAPI flow cytometry and bioluminescence cell counting. Gene expression and protein data from MM1S cells treated with BMA-CM revealed a significant increase in fatty acid binding protein 4 (FABP4), a fatty acid shuttling molecule with broad signaling effects (pcr: p<.01, ELISA: p<0.0001). While unknown in MM, the FABP family has demonstrated pro-tumorigenic effects in other cancers. We used inhibitors of FABP4 (iFABP4), and its compensatory FABP5 family member, to study their effects on basal and dex-induced apoptosis, cell number, cell cycle and proliferation in MM1S cells. After 72 hours, FABP4i and FABP5i alone, and in combination, significantly decreased cell number and proliferation. In combination, FABP4i/FABP5i improved efficacy of dex. Decreases in MM1S cell number and proliferation, (assessed by BLI, Ki67 and cell cycle flow cytometry analyses) from FABP4i, FABP5i, or the FABP4i/FABP5i combination were attributed to increased sub G1/G0 population. Overall, targeting BMAT and FABPs may be novel approaches to inhibiting progression and decreasing the drug resistance properties of MM cells in the BM.

Steric Protection of Rhodium‐Nitridyl Radical Species

In an attempt to synthesize a mononuclear rhodium nitridyl complex with a reduced tendency to undergo nitridyl radical N–N coupling, we synthesized a bulky analog of Milstein's bipyridine‐based PNNH ligand, bearing a tert‐butyl group at the 6′ position of the bipyridine moiety. A three‐step synthetic route toward this new bulky tBu3PNNH ligand was developed, involving a selective nucleophilic substitution step, followed by a Stille coupling and a final hydrophosphination step to afford the desired 6‐(tert‐butyl)‐6′‐[(di‐tert‐butylphosphino)methyl]‐2,2′‐bipyridine (tBu3PNNH) ligand. This newly developed tBu3PNNH ligand was incorporated in the synthesis of the sterically protected azide complex [Rh(N3)(tBu3PNNH)]. We explored N2 elimination form this species using photolysis and thermolysis, hoping to synthesize a mononuclear rhodium complex with a terminal nitrido moiety. Characterization of the reaction product(s) using NMR, coldspray HR‐ESI‐MS and EPR spectroscopy shows that the material is paramagnetic, and data obtained by MS spectrometry revealed masses corresponding with both monomeric and dimeric nitrido/nitridyl complexes. NMR only reveals broad uncharacteristic signals and the complex is EPR silent at 8K or above. The combined data point to formation of a paramagnetic [(tBu3PNN)Rh(µ‐N)Rh(tBu3PNN)] species. It thus seems that despite its three tBu groups the new ligand is not bulky enough to prevent formation of Rh–N–Rh bridged species. However, the increased steric environment does prevent further reaction with carbon monoxide, which is unable to coordinate to rhodium.