13 research outputs found
TeacherLM: Teaching to Fish Rather Than Giving the Fish, Language Modeling Likewise
Large Language Models (LLMs) exhibit impressive reasoning and data
augmentation capabilities in various NLP tasks. However, what about small
models? In this work, we propose TeacherLM-7.1B, capable of annotating relevant
fundamentals, chain of thought, and common mistakes for most NLP samples, which
makes annotation more than just an answer, thus allowing other models to learn
"why" instead of just "what". The TeacherLM-7.1B model achieved a zero-shot
score of 52.3 on MMLU, surpassing most models with over 100B parameters. Even
more remarkable is its data augmentation ability. Based on TeacherLM-7.1B, we
augmented 58 NLP datasets and taught various student models with different
parameters from OPT and BLOOM series in a multi-task setting. The experimental
results indicate that the data augmentation provided by TeacherLM has brought
significant benefits. We will release the TeacherLM series of models and
augmented datasets as open-source.Comment: 5 figures, 15 page
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
DNA binding and cleavage modes of shishijimicin A
Although shishijimicin A and its extreme potencies against an array of cancer cell lines have been known for more than a decade, its assumed DNA-cleaving mechanism has not been substantiated as yet. Herein we report studies that reveal binding and scission of double-stranded DNA by shishijimicin A. The results of these studies support the proposed hypothesis that DNA strand scissions are caused by 1,4-benzenoid diradicals formed by Bergman cycloaromatization of the enediyne core of shishijimicin A upon activation by thiols. In addition, double-stranded supercoiled DNA-cleavage experiments with shishijimicin A in competition with known minor groove binders, UV spectroscopic studies, and electrophoretic analysis were utilized to clarify the binding mode of the molecule to DNA. These investigations indicate that shishijimicin A binds to the minor groove of double-stranded DNA and that its β-carboline moiety plays a role in the binding through intercalation. In addition, due to the fact that naked linker regions of DNA in the interphase and metaphase of eukaryotic cells are unprotected by histone proteins during entire cell cycles and because these unprotected regions of DNA are vulnerable to attack by DNA binders, it was concluded that the observed double-strand DNA cleavage and very low sequence selectivity by shishijimicin A may account for its extraordinary cytotoxicity.Agency for Science, Technology and Research (A*STAR)T.L., H.Z, and S.B. acknowledge support by the Agency for Science, Technology and Research (A*STAR), Singapore (SERC A1883c0007). K.C.N., E.N.P., R.L., and Z.L. acknowledge support by the Cancer Prevention Research Institute of Texas (CPRIT), The Welch Foundation (grant C-1819), AbbVie Stemcentrx, and Rice University
Adsorption of Myricetrin, Puerarin, Naringin, Rutin, and Neohesperidin Dihydrochalcone Flavonoids on Macroporous Resins
The
adsorption properties (equilibrium, kinetics, and column breakthrough)
of five model flavonoids (myricetrin, puerarin, naringin, rutin and
neohesperidin dihydrochalcone) on selected macroporous resins were
investigated in order to identify a suitable resin adsorbent for effective
separation and purification of flavonoids from the extracts of herbal
plants. It was observed that the resins with a low polarity and a
high specific surface area have high adsorption capacities for all
five flavonoids. Both the Langmuir and Freundlich isotherm equations
correlate well the adsorption equilibrium data of the five flavonoids
on four selected resins, and adsorption enthalpy, entropy, and free
energy of the five flavonoids on HPD300 resin were calculated from
the adsorption isotherms by the Freundlich equation constants. The
pseudo-second-order adsorption rate equation fits the kinetic data
on four selected resins better than the pseudo-first-order adsorption
rate equation, and the initial adsorption rates were calculated and
discussed. The HPD300 resin was selected as the most promising adsorbent
for a preliminary separation and purification of flavonoids because
of its excellent adsorption/desorption properties including high adsorption
rates for all five flavonoids. The adsorption breakthrough experiment
with a synthetic flavonoid mixture solution on the HPD300 resin further
confirmed that the HPD300 resin can separate the five flavonoids effectively,
especially for purifying neohesperidin dihydrochalcone from the flavonoid
mixtures
Total Synthesis and Full Structural Assignment of Namenamicin
Namenamicin
is a rare natural product possessing potent cytotoxic
properties that may prove useful as a lead compound for payloads of
antibody–drug conjugates (ADCs). Its scarcity, coupled with
the uncertainty of its full absolute configuration, elevates it to
an attractive synthetic target. Herein we describe the total synthesis
of the two C7′-epimers of namenaÂmicin and assign its
complete structure, opening the way for further chemical and biological
studies toward the discovery of potent payloads for ADCs directed
toward targeted cancer therapies
Total Synthesis of Shishijimicin A
The
total synthesis of the rare but extremely potent antitumor
agent shishijimicin A has been achieved via a convergent strategy
involving carboline disaccharide <b>3</b> and hydroxy enediyne
thioacetate <b>4</b>