Infra-red absorption spectra and molecular structure of triatomic molecules

This report is written as a résumé of investigations of infra -red absorption spectra of triatomic molecules carried out during tenure of a Senior Research Award. It might have been written in thesis form giving details of experimental and other work, but much of this has already been published, and copies of the papers have been sent the Department; these papers run into some hundred pages of print, and a thesis would merely form unnecessary repetition occupying almostdouble thib number of typewritten pages. A resume which brings together the results, and gives the now well established methods of interpreting infra -red absorption spectra of triatomic molecules, seems therefore the more satisfactory form for the report.Published work will be referred to as follows: 'Investigations in the Infra -Red Region of the Spectrum' (1). Part I (Froc. Roy. Soc., 1930, A, 130, 133). || (2). Part II. (ibis, 1930, A, 130, 142). || (3). Part III. (ibid, 1931, A, 132, 236). || (4). Part IV. (ibid, 1931, A, 132, 252). || (5). Part V. (ibid, 1932, A, 135, 375). || (6). Part VI. (ibid, 1932, A, 137, 622).- || (7). Fart VII. (ibid, 1932, A, 138, 531). || (8). Part VIII. (ibid, 1933, A, 140, 193). || (a). Part IX. (ibid, 1933, A, 142, 129). || (b). Part X (ibid, 1934, A, 145, 338). || (9). 'Infra -Red and Raman Bands of Carbon Dioxide, Carbonyl Sulphide, and Carbon Disulphide'. (Z. Physik, 1932, 79, 35). || (10). 'Molecular Configuration of N20.' (Phys. Rev., 1932, 39, 534). || (11). 'Infra -Red Absorption Spectrum of Nitrogen Dioxide'. || (Nature, 1933, 131, 239). (12). 'The Asymmetrical Rotator and its Infra -Red Spectrum'. (Trans. Faraday Soc., 1930, XXVI, 197). || (13). 'A Method of Eliminating Magnetic Disturbance of High Sensitivity Galvanometers'. (J. Sci. Inst., 1930, VII). || (14). 'Structure of Triatomic I.Iolecules'. A. B. D. Cassie (Nature, 1933, 131, 438). || (15). 'Investigations of the Infra -Red Absorption Spectra of Sulphur Dioxide, Carbon Disulphide, and Carbonyl Sulphide'. A thesis for the Ph.D. degree at London University, by A. B. D. Cassie, June 1931. || (16). 'Investigations in the Infra -Red Region of the Spectrum Part XI - The Absorption Spectrum and Molecular Configuration of Boron Trichioride, and the Effect of Strain on Plane Groups of the Type XYs. (Proc. Roy. Soc., 1935, A, 148, 87).This work has been published in collaboration with Mr. C. R. Bailey, Lecturer at University College, London, apart from references (13), (14), (15), and (16)

Spontaneous Breakdown of Superhydrophobicity

In some cases water droplets can completely wet micro-structured superhydrophobic surfaces. The {\it dynamics} of this rapid process is analyzed by ultra-high-speed imaging. Depending on the scales of the micro-structure, the wetting fronts propagate smoothly and circularly or -- more interestingly -- in a {\it stepwise} manner, leading to a growing {\it square-shaped} wetted area: entering a new row perpendicular to the direction of front propagation takes milliseconds, whereas once this has happened, the row itself fills in microseconds ({\it ``zipping''})Comment: Accepted for publication in Physical Review Letter

A Randomized, Double-Blinded, Phase II Trial of Gemcitabine and Nab-Paclitaxel Plus Apatorsen or Placebo in Patients with Metastatic Pancreatic Cancer: The RAINIER Trial.

Lessons learnedThe addition of the heat shock protein 27 (Hsp27)-targeting antisense oligonucleotide, apatorsen, to a standard first-line chemotherapy regimen did not result in improved survival in unselected patients with metastatic pancreatic cancer.Findings from this trial hint at the possible prognostic and predictive value of serum Hsp27 that may warrant further investigation.BackgroundThis randomized, double-blinded, phase II trial evaluated the efficacy of gemcitabine/nab-paclitaxel plus either apatorsen, an antisense oligonucleotide targeting heat shock protein 27 (Hsp27) mRNA, or placebo in patients with metastatic pancreatic cancer.MethodsPatients were randomized 1:1 to Arm A (gemcitabine/nab-paclitaxel plus apatorsen) or Arm B (gemcitabine/nab-paclitaxel plus placebo). Treatment was administered in 28-day cycles, with restaging every 2 cycles, until progression or intolerable toxicity. Serum Hsp27 levels were analyzed at baseline and on treatment. The primary endpoint was overall survival (OS).ResultsOne hundred thirty-two patients were enrolled, 66 per arm. Cytopenias and fatigue were the most frequent grade 3/4 treatment-related adverse events for both arms. Median progression-free survival (PFS) and OS were 2.7 and 5.3 months, respectively, for arm A, and 3.8 and 6.9 months, respectively, for arm B. Objective response rate was 18% for both arms. Patients with high serum level of Hsp27 represented a poor-prognosis subgroup who may have derived modest benefit from addition of apatorsen.ConclusionAddition of apatorsen to chemotherapy does not improve outcomes in unselected patients with metastatic pancreatic cancer in the first-line setting, although a trend toward prolonged PFS and OS in patients with high baseline serum Hsp27 suggests this therapy may warrant further evaluation in this subgroup

Molecular Dynamics Simulation Study of Interaction between Model Rough Hydrophobic Surfaces

We study some aspects of hydrophobic interaction between molecular rough and flexible model surfaces. The model we use in this work is based on a model we used previously (Eun, C.; Berkowitz, M. L. J. Phys. Chem. B 2009, 113, 13222-13228), when we studied the interaction between model patches of lipid membranes. Our original model consisted of two graphene plates with attached polar headgroups; the plates were immersed in a water bath. The interaction between such plates can be considered as an example of a hydrophilic interaction. In the present work we modify our previous model by removing the charge from the zwitterionic headgroups. As a result of this procedure, the plate character changes; it becomes hydrophobic. By separating the total interaction (or potential of mean force, PMF) between plates into the direct and the water-mediated interactions we observe that the latter changes from repulsive to attractive, clearly emphasizing the important role of water as a medium. We also investigate the effect of roughness and flexibility of the headgroups on the interaction between plates and observe that roughness enhances the character of the hydrophobic interaction. The presence of a dewetting transition in a confined space between charge-removed plates confirms that the interaction between plates is strongly hydrophobic. In addition, we notice that there is a shallow local minimum in the PMF in case of charge-removed plates. We find that this minimum is associated with the configurational changes that flexible headgroups undergo, as the two plates are brought together.Comment: 27 pages, 9 figure

Biomimetic transferable surface for a real time control over wettability and photoerasable writing with water drop lens

We demonstrate a transferable device that can turn wettability of surfaces to sticky or slippy, as per requirement. It is composed of polymeric yarn with a fibrous structure, which can be lifted and placed on any surface to render it the unique wettability properties. We introduce Polyvinylidenefluoride (PVDF) random fiber as biomimetic rose petal surface. When it is decorated with PVDF nanofibers yarns, the random mesh transform from rose petal sticky state into grass leaf slippy state. When it is placed on sticky, hydrophilic metal coin, it converts the surface of the coin to super hydrophobic. Adjustments in the yarn system, like interyarn spacing, can be done in real time to influence its wettability, which is a unique feature. Next, we load the polymer with a photochromic compound for chemical restructuring. It affects the sliding angle of water drop and makes the fibers optically active. We also demonstrate a “water droplets lens” concept that enables erasable writing on photochromic rose petal sticky fibrous surface. The droplet on a highly hydrophobic surface acts as a ball lens to concentrate light onto a hot spot; thereby we demonstrate UV light writing with water lenses and visible light erasing

Biocompatible polymeric microparticles produced by a simple biomimetic approach

The use of superhydrophobic surfaces to produce polymeric particles proves to be biologically friendly since it entails the pipetting and subsequent cross-linking of polymeric solutions under mild experimental conditions. Moreover, it renders encapsulation efficiencies of ∼100%. However, the obtained particles are 1 to 2 mm in size, hindering to a large extent their application in clinical trials. Improving on this technique, we propose the fabrication of polymeric microparticles by spraying a hydrogel precursor over superhydrophobic surfaces followed by photo-cross-linking. The particles were produced from methacrylamide chitosan (MA-CH) and characterized in terms of their size and morphology. As demonstrated by optical and fluorescence microscopy, spraying followed by photo-cross-linking led, for the first time, to the production of spherical particles with diameters on the order of micrometers, nominal sizes not attainable by pipetting. Particles such as these are suitable for medical applications such as drug delivery and tissue engineering.We thank Ivo Aroso and Ana Isabel Neto for their valuable support with FTIR and compression experiments, respectively. A.M.S.C. thanks FCT for financial support through grant BIM/PTDC/CTM-BPC/112774/2009_02. M.A.-M. thanks CONACyT (Mexico) for financial support through post-doc grant no. 203732. N.M.O. thanks FCT for financial support through Ph.D. scholarship no. SFRH/BD/73172/2010. This work was funded by the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS, by FEDER through the Competitive Factors Operation Program-COMPETE, and by national funds through FCT - Fundacao para a Ciencia e a Tecnologia in the scope of project PTDC/CTM-BIO/1814/2012

JWST's TEMPLATES for Star Formation: The First Resolved Gas-Phase Metallicity Maps of Dust-Obscured Star-Forming Galaxies at zz ∼\sim 4

We present the first spatially resolved maps of gas-phase metallicity for dust-obscured star-forming galaxies (DSFGs) at $z$ $\sim$ 4, from the JWST TEMPLATES Early Release Science program, derived from NIRSpec integral field unit spectroscopy of the H$\alpha$ and [NII] emission lines. Empirically derived literature optical line calibrations are used to determine that the sources are highly metal rich, with both appearing to display regions of supersolar metallicity, particularly in SPT2147-50. While we cannot rule out shocks or AGN in these regions, we suggest that the two systems have already undergone significant enrichment as a result of their extremely high star-formation rates. Utilising ALMA rest-frame 380$\mu$m continuum and [CI]($^3$P$_2$-$^3$P$_1$) line maps we compare metallicity and gas-to-dust ratio variations in the two galaxies, finding the two to be anticorrelated on highly resolved spatial scales, consistent with various literature studies of $z$ $\sim$ 0 galaxies. The data are indicative of the enormous potential of JWST to probe the enrichment of the interstellar medium on $\sim$kpc scales in extremely dust-obscured systems at $z$ $\sim$ 4 and beyond.Comment: 12 pages, 5 figures, submitted to Ap

Superhydrophobic paper in the development of disposable labware and lab-on-paper devices

Traditionally in superhydrophobic surfaces history, the focus has frequently settled on the use of complex processing methodologies using nonbiodegradable and costly materials. In light of recent events on lab-on-paper emergence, there are now some efforts for the production of superhydrophobic paper but still with little development and confined to the fabrication of flat devices. This work gives a new look at the range of possible applications of bioinspired superhydrophobic paper-based substrates, obtained using a straightforward surface modification with poly(hydroxybutyrate). As an end-of-proof of the possibility to create lab-on-chip portable devices, the patterning of superhydrophobic paper with different wettable shapes is shown with low-cost approaches. Furthermore, we suggest the use of superhydrophobic paper as an extremely low-cost material to design essential nonplanar lab apparatus, including reservoirs for liquid storage and manipulation, funnels, tips for pipettes, or accordion-shaped substrates for liquid transport or mixing. Such devices take the advantage of the self-cleaning and extremely water resistance properties of the surfaces as well as the actions that may be done with paper such as cut, glue, write, fold, warp, or burn. The obtained substrates showed lower propensity to adsorb proteins than the original paper, kept superhydrophobic character upon ethylene oxide sterilization and are disposable, suggesting that the developing devices could be especially adequate for use in contact with biological and hazardous materials

Ultra-Fast Oleophobic-Hydrophilic Switching Surfaces for Anti-Fogging, Self-Cleaning, and Oil-Water Separation

Smooth copolymer–fluorosurfactant complex film surfaces are found to exhibit fast oleophobic–hydrophilic switching behavior. Equilibration of the high oil contact angle (hexadecane = 80°) and low water contact angle (110°), which, when combined with the inherent ultrafast switching speed, yields oil–water mixture separation efficiencies exceeding 98%