Visible,near‐infrared,and ultraviolet laser‐excited Raman spectroscopy of the monocytes/macrophages (U937) cells

Raman spectra of the monocytes were recorded with laser excitation at 532, 785, 830, and 244 nm. The measurements of the Raman spectra of monocytes excited with visible, near‐infrared (NIR), and ultraviolet (UV) lasers lad to the following conclusions. (1) The Raman peak pattern of the monocytes can be easily distinguished from those of HeLa and yeast cells; (2) Positions of the Raman peaks of the dried cell are in coincidence with those of the monocytes in a culture cell media. However, the relative intensities of the peaks are changed: the peak centered around 1045 cm⁻¹ is strongly intensified. (3) Raman spectra of the dead monocytes are similar to those of living cells with only one exception: the Raman peak centered around 1004 cm⁻¹ associated with breathing mode of phenylalanine is strongly intensified. The Raman spectra of monocytes excited with 244‐nm UV laser were measured on cells in a cell culture medium. A peak centered at 1485 cm⁻¹ dominates the UV Raman spectra of monocytes. The ratio I₁₅₇₄/I₁₆₁₃ for monocytes is found to be around 0.71. This number reflects the ratio between proteins and DNA content inside a cell and it is found to be twice as high as that of E. coli and 5 times as high as that of gram‐positive bacteria. Copyright © 2009 John Wiley & Sons, Ltd.     

Quantum spreading of a self-gravitating wave-packet in singularity free gravity

In this paper we will study for the first time how the wave-packet of a self-gravitating meso-scopic system spreads in theories beyond Einstein’s general relativity. In particular, we will consider a ghost-free infinite derivative gravity, which resolves the 1 / r singularity in the potential – such that the gradient of the potential vanishes within the scale of non-locality. We will show that a quantum wave-packet spreads faster for a ghost-free and singularity-free gravity as compared to the Newtonian case, therefore providing us a unique scenario for testing classical and quantum properties of short-distance gravity in a laboratory in the near future.     

Supramolecular Barrel-Rosette Ion Channel Based on 3,5-Diaminobenzoic Acid for Cation-Anion Symport

The structural tropology and functions of natural cation-anion symporting channels have been continuously investigated due to their crucial role in regulating various physiological functions. To understand the physiological functions of the natural symporter channels, it is vital to develop small-molecule-based biomimicking systems that can provide mechanistic insights into the ion-binding sites and the ion-translocation pathways. Herein, we report a series of bis((R)-(−)-mandelic acid)-linked 3,5-diaminobenzoic acid based self-assembled ion channels with distinctive ion transport ability. Ion transport experiment across the lipid bilayer membrane revealed that compound 1 b exhibits the highest transport activity among the series, and it has interesting selective co-transporting functions, i.e., facilitates K⁺/ClO₄⁻ symport. Electrophysiology experiments confirmed the formation of supramolecular ion channels with an average diameter of 6.2±1 Å and single channel conductance of 57.3±1.9 pS. Selectivity studies of channel 1 b in a bilayer lipid membrane demonstrated a permeability ratio of , , and indicating the higher selectivity of the channel towards KClO₄ over KCl salt. A hexameric assembly of a trimeric rosette of 1 b was subjected to molecular dynamics simulations with different salts to understand the supramolecular channel formation and ion selectivity pattern.     

Pd-Catalyzed Regioselective Domino C−C Bond Formation to Access N-Fused Benzimidazo-Indolo-Isoquinoline Heterocycles

Regioselective synthesis of N-fused benzimidazo-indolo-isoquinoline heterocycles via Pd-catalyzed domino coupling reaction of 1-(1-methyl-1H-indol-2-yl)-1H-benzimidazoles and aryl halides was developed. This one pot methodology proceeded via a five-member carbopalladacycle intermediate and provided direct and facile route to access structurally complex polyheterocycles in moderate to good yields. These unique hybrid molecules resembled structural similarity with naturally isolated alkaloids. Notably, the present domino process occurred through activation of three C−H bonds and the simultaneous formation of two new C−C bonds in one-shot. These molecules exhibited strong solid and solution phase fluorescence and their emission spectra in both the medium are reported here.     

Rapid prototyping of polydimethylsiloxane (PDMS) microchips using electrohydrodynamic jet printing: Application to electrokinetic assays

Polydimethylsiloxane (PDMS) based microfluidic devices have found increasing utility for electrophoretic and electrokinetic assays because of their ease of fabrication using replica molding. However, the fabrication of high-resolution molds for replica molding still requires the resource-intensive and time-consuming photolithography process, which precludes quick design iterations and device optimization. We here demonstrate a low-cost, rapid microfabrication process, based on electrohydrodynamic jet printing (EJP), for fabricating non-sacrificial master molds for replica molding of PDMS microfluidic devices. The method is based on the precise deposition of an electrically stretched polymeric solution of polycaprolactone in acetic acid on a silicon wafer placed on a computer-controlled motion stage. This process offers the high-resolution (order 10 $\mu$m) capability of photolithography and rapid prototyping capability of inkjet printing to print high-resolution templates for elastomeric microfluidic devices within a few minutes. Through proper selection of the operating parameters such as solution flow rate, applied electric field, and stage speed, we demonstrate microfabrication of intricate master molds and corresponding PDMS microfluidic devices for electrokinetic applications. We demonstrate the utility of the fabricated PDMS microchips for nonlinear electrokinetic processes such as electrokinetic instability and controlled sample splitting in ITP. The ability to rapid prototype customized reusable master molds with order 10 $\mu$m resolution within a few minutes can help in designing and optimizing microfluidic devices for various electrokinetic applications.