Report of the Committee on Resolutions- Declaration

Pamphlet concerning a declaration made by the National Educational Association at the forty-third annual convention

Oligodendrocyte Nf1 Controls Aberrant Notch Activation and Regulates Myelin Structure and Behavior

The RASopathy neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant genetic disorders. In NF1 patients, neurological issues may result from damaged myelin, and mice with a neurofibromin gene (Nf1) mutation show white matter (WM) defects including myelin decompaction. Using mouse genetics, we find that altered Nf1 gene-dose in mature oligodendrocytes results in progressive myelin defects and behavioral abnormalities mediated by aberrant Notch activation. Blocking Notch, upstream mitogen-activated protein kinase (MAPK), or nitric oxide signaling rescues myelin defects in hemizygous Nf1 mutants, and pharmacological gamma secretase inhibition rescues aberrant behavior with no effects in wild-type (WT) mice. Concomitant pathway inhibition rescues myelin abnormalities in homozygous mutants. Notch activation is also observed in Nf1+/− mouse brains, and cells containing active Notch are increased in NF1 patient WM. We thus identify Notch as an Nf1 effector regulating myelin structure and behavior in a RASopathy and suggest that inhibition of Notch signaling may be a therapeutic strategy for NF1

Predictive energetic tuning of quinoid O-nucleophiles for the electrochemical capture of carbon dioxide

The need for robust, scalable methods for the capture and storage of carbon dioxide is increasingly pressing. Electric power-based carbon capture methods have drawn attention as a promising strategy due to their potential to couple to renewable energy sources. Materials for the capture of CO2 from air need to overcome the challenges of parasitic reactivity with oxygen, selective removal of CO2 at 415 ppm, and long-term durability in air. Quinones and their reduced forms are a promising family of such sorbents. However, the design of robust quinone sorbents has been limited, and no systematic study exists that unifies the relationship between reduction potential, binding free energy and the effect of CO2 concentration on the average number of CO2 molecules captured. Our work addresses this knowledge gap through a synergistic computational and experimental study of a family of electrochemically generated quinoid molecular sorbents for CO2 capture with tunable redox chemistries. Our findings indicate that while quinones with reduction potentials positive of oxygen reduction exist, the O-nucleophiles generated at these potentials are weak CO2 binders. Using microkinetic analysis to examine binding speciation, we identify sorbent candidates that bind one CO2 molecule within a narrow potential window positive of oxygen reduction. This behavior is calculated to occur at CO2 concentrations relevant to direct air capture. Additionally, while electron-rich quinones are found to generally bind two CO2 units per quinone dianion with little variation across CO2 concentrations relevant to carbon capture, weaker quinones generally exhibit lower stoichiometries and are more sensitive to CO2 concentration. Furthermore, we establish a linear correlation between the second reduction potential of a quinone and the free energy of binding CO2 to the quinone dianion. This correlation has important predictive power, as it allows new molecular materials of the quinoid family to be assessed with simple electrochemical measurements. However, based on our findings, such analyses must be punctuated by careful considerations of reaction stoichiometry and operating concentration ranges. &nbsp;</p

Predictive energetic tuning of C-Nucleophiles for the electrochemical capture of carbon dioxide

This work maps the thermodynamics of electrochemically generated C-nucleophiles for reactive capture of CO2. We identify a linear relationship between the pKa, the reduction potential of a protonated nucleophile (Ered), and the nucleophile&rsquo;s free energy of CO2 binding (&Delta;Gbind). Through synergistic experiments and computations, this study establishes a three-parameter correlation described by the equation &Delta;Gbind=&minus;0.78pKa+4.28Ered+20.95 for a series of twelve imidazol(in)ium/N-heterocyclic carbene pairs with an R2 of 0.92. The correlation allows us to predict the &Delta;Gbind of C-nucleophiles to CO2 using reduction potentials or pKas of imidazol(in)ium cations. The carbenes in this study were found to exhibit a wide range CO2 binding strengths, from strongly CO2 binding to nonspontaneous. This observation suggests that the &Delta;Gbind of imidazol(in)ium-based carbenes is tunable to a desired strength by appropriate structural changes. This work sets the stage for systematic energetic tuning of electrochemically enabled reactive separations. &nbsp;</p

Archeological Investigations at the Santa Maria Creek Site (41CW104) Caldwell County, Texas

The excavations by Atkins at the Santa Maria Creek site (41CW104) described in the following report have succeeded in bringing together a myriad of information regarding aboriginal occupations in eastern Central Texas at the dawn of the Historic period. The analysis of the materials recovered from National Register of Historic Places testing and data recovery has demonstrated that even a site buried in sandy, bioturbated sediments can still significantly add to the archeological record. This becomes even more important for areas such as Caldwell County, Texas, which have witnessed few such investigations. The report utilized a wide array of analytical techniques to unravel the site, including extensive ethnohistorical research, artifact analysis, special studies, and experimental archeology

Evaluating Hammermill Tip Speed, Air Assist, and Screen Hole Diameter on Ground Corn Characteristics

Whole yellow dent #2 corn was ground using two 43 mm Andritz hammermills (Model: 4330-6, Andritz Feed & Biofuel, Muncy, PA; JBS Live Pork LLC Feed Mill, Fremont, IA). Both mills discharged to a shared plenum where samples were collected via a sample port. Each mill was equipped with 72 hammers and 300 HP motors on a variable frequency drive (VFD). Corn was ground on 3 separate days to create replication and treatments were randomized within replication. Treatments were arranged in a 3 × 3 × 3 factorial design with 3 tip speeds (12,383, 16,323, and 20,263 ft/min); 3 screen hole diameters (6/64, 10/64, and 16/64 in.); and 3 air assist system fan RPM’s (60, 80, and 100% of fan motor load). Samples of each treatment were collected and analyzed for moisture, particle size, and flowability characteristics. Particle size analysis was completed using a 13-sieve stack with the inclusion of sieve agitators and flow agent. Flowability characteristics were evaluated using a composite flow index (CFI), which includes percent compressibility, angle of repose (AoR), and critical orifice diameter (COD). Data were analyzed as a 3 × 3 × 3 factorial using the PROC GLIMMIX procedure of SAS with grinding run as the experimental unit and sample collection day as a blocking factor. There were no 3-way interactions for screen hole diameter × hammer tip speed × air flow for the geometric mean diameter (dgw) or any flowability characteristics of ground corn. There was a 3-way interaction for particle size standard deviation (Sgw), (linear screen hole diameter × linear hammer tip speed × linear air flow, P = 0.029). There was a linear screen hole diameter × linear hammer tip speed interaction (P = 0.001) for dgw. When tip speed increased from 12,383 to 20,263 ft/min, the rate of decrease in dgw was greater as screen hole diameter increased from 6/64 to 16/64 in. An interaction of screen hole diameter and hammer tip speed (linear × linear, P = 0.040) was also observed for the CFI. The CFI results increased with increasing screen hole diameter when corn was ground using a hammer tip speed of 12,383 ft/min but no differences were observed as tip speed increased to 16,323 and 20,263 ft/min. An interaction of screen hole diameter and hammer tip speed (quadratic × quadratic, P = 0.001) was observed for mill motor load. Mill motor load decreased as screen hole diameter increased from 6/64 in. to 16/64 in., but increased as hammer tip speed was increased with the most significant reductions being observed as tip speed increased from 12,383 ft/min to 16,323 ft/min on the 6/64 in. screen. In conclusion, hammer tip speed and air flow rate are viable options for adjusting ground material characteristics when grinding using a hammermill, alongside the traditional screen variations. Along with the range of particle sizes capable of being produced, an increased level of accuracy can also be achieved with hammer tip speed and air flow adjustments with minimal down time necessary for screen changes

ARID1B is a specific vulnerability in ARID1A-mutant cancers

Summary Recent studies have revealed that ARID1A is frequently mutated across a wide variety of human cancers and also has bona fide tumor suppressor properties. Consequently, identification of vulnerabilities conferred by ARID1A mutation would have major relevance for human cancer. Here, using a broad screening approach, we identify ARID1B, a related but mutually exclusive homolog of ARID1A in the SWI/SNF chromatin remodeling complex, as the number one gene preferentially required for the survival of ARID1A-mutant cancer cell lines. We show that loss of ARID1B in ARID1A-deficient backgrounds destabilizes SWI/SNF and impairs proliferation. Intriguingly, we also find that ARID1A and ARID1B are frequently co-mutated in cancer, but that ARID1A-deficient cancers retain at least one ARID1B allele. These results suggest that loss of ARID1A and ARID1B alleles cooperatively promotes cancer formation but also results in a unique functional dependence. The results further identify ARID1B as a potential therapeutic target for ARID1A-mutant cancers

Measurement of the B0_s semileptonic branching ratio to an orbitally excited D_s** state, Br(B0_s -> Ds1(2536) mu nu)

In a data sample of approximately 1.3 fb-1 collected with the D0 detector between 2002 and 2006, the orbitally excited charm state D_s1(2536) has been observed with a measured mass of 2535.7 +/- 0.6 (stat) +/- 0.5 (syst) MeV via the decay mode B0_s -> D_s1(2536) mu nu X. A first measurement is made of the branching ratio product Br(b(bar) -> D_s1(2536) mu nu X).Br(D_s1(2536)->D* K0_S). Assuming that D_s1(2536) production in semileptonic decay is entirely from B0_s, an extraction of the semileptonic branching ratio Br(B0_s -> D_s1(2536) mu nu X) is made.Comment: 7 pages, 2 figures, LaTeX, version with minor changes as accepted by Phys. Rev. Let

Simultaneous measurement of the ratio B(t->Wb)/B(t->Wq) and the top quark pair production cross section with the D0 detector at sqrt(s)=1.96 TeV

We present the first simultaneous measurement of the ratio of branching fractions, R=B(t->Wb)/B(t->Wq), with q being a d, s, or b quark, and the top quark pair production cross section sigma_ttbar in the lepton plus jets channel using 0.9 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV collected with the D0 detector. We extract R and sigma_ttbar by analyzing samples of events with 0, 1 and >= 2 identified b jets. We measure R = 0.97 +0.09-0.08 (stat+syst) and sigma_ttbar = 8.18 +0.90-0.84 (stat+syst)} +/-0.50 (lumi) pb, in agreement with the standard model prediction.Comment: submitted to Phys.Rev.Letter

Search for charged Higgs bosons decaying to top and bottom quarks in ppbar collisions

We describe a search for production of a charged Higgs boson, q \bar{q'} -> H^+, reconstructed in the t\bar{b} final state in the mass range 180 <= M_{H^+} <= 300 GeV. The search was undertaken at the Fermilab Tevatron collider with a center-of-mass energy sqrt{s} = 1.96 TeV and uses 0.9 fb^{-1} of data collected with the D0 detector. We find no evidence for charged Higgs boson production and set upper limits on the production cross section in the Types I, II and III two-Higgs-doublet models (2HDMs). An excluded region in the (M_{H^+},tan\beta) plane for Type I 2HDM is presented.Comment: Submitted to Phys. Rev. Letter