Classical stochastic discrete time crystals.

We describe a general and simple paradigm for discrete time crystals (DTCs), systems with a stable subharmonic response to an external driving field, in a classical thermal setting. We consider, specifically, an Ising model in two dimensions, as a prototypical system with a phase transition into stable phases distinguished by a local order parameter, driven by thermal dynamics and periodically kicked with a noisy protocol. By means of extensive numerical simulations for large sizes-allowed by the classical nature of our model-we show that the system features a true disorder-DTC order phase transition as a function of the noise strength, with a robust DTC phase extending over a wide parameter range. We demonstrate that, when the dynamics is observed stroboscopically, the phase transition to the DTC state appears to be in the equilibrium two-dimensional Ising universality class. However, we explicitly show that the DTC is a genuine nonequilibrium state. More generally, we speculate that systems with thermal phase transitions to multiple competing phases can give rise to DTCs when appropriately driven.

Nonlocality and short-range wetting phenomena.

We propose a nonlocal interfacial model for 3D short-range wetting at planar and nonplanar walls. The model is characterized by a binding-potential functional depending only on the bulk Ornstein-Zernike correlation function, which arises from different classes of tubelike fluctuations that connect the interface and the substrate. The theory provides a physical explanation for the origin of the effective position-dependent stiffness and binding potential in approximate local theories and also obeys the necessary classical wedge covariance relationship between wetting and wedge filling. Renormalization group and computer simulation studies reveal the strong nonperturbative influence of nonlocality at critical wetting, throwing light on long-standing theoretical problems regarding the order of the phase transition.

Directed self-assembly of monodisperse phospholipid bilayer Nanodiscs with controlled size.

Using a recently described self-assembly process (Bayburt, T. H.; Grinkova, Y. V.; Sligar, S. G. Nano Letters 2002, 2, 853-856), we prepared soluble monodisperse discoidal lipid/protein particles with controlled size and composition, termed Nanodiscs, in which the fragment of dipalmitoylphosphatidylcholine (DPPC) bilayer is surrounded by a helical protein belt. We have customized the size of these particles by changing the length of the amphipathic helical part of this belt, termed membrane scaffold protein (MSP). Herein we describe the design of extended and truncated MSPs, the optimization of self-assembly for each of these proteins, and the structure and composition of the resulting Nanodiscs. We show that the length of the protein helix surrounding the lipid part of a Nanodisc determines the particle diameter, as measured by HPLC and small-angle X-ray scattering (SAXS). Using different scaffold proteins, we obtained Nanodiscs with the average size from 9.5 to 12.8 nm with a very narrow size distribution (+/-3%). Functionalization of the N-terminus of the scaffold protein does not perturb their ability to form homogeneous discoidal structures. Detailed analysis of the solution scattering confirms the presence of a lipid bilayer of 5.5 nm thickness in Nanodiscs of different sizes. The results of this study provide an important structural characterization of self-assembled phospholipid bilayers and establish a framework for the design of soluble amphiphilic nanoparticles of controlled size.

Absence of evidence for an etiologic role for Epstein-Barr virus in neoplasms of the lung and pleura.

Although most lung carcinomas and mesotheliomas are associated with well-known risk factors, these cancers develop in only a minority of persons exposed to known risk factors. On the other hand, these cancers develop in some patients without exposure to known risk factors. This indicates that other environmental factors play a role in the carcinogenesis of these tumors. Oncogenic viruses such as Epstein-Barr virus (EBC) are well-established agents in the development of certain cancers. EBV genomes have been detected by in situ hybridization in gastric adenocarcinomas and in nasopharyngeal carcinomas. To determine whether EBV infection is associated with pulmonary adenocarcinoma or mesothelioma, we performed EBV-encoded RNA-1 in situ hybridization on 80 pulmonary adenocarcinoma and 50 mesothelioma resection specimens. Sections were cut from paraffin-embedded tissue and EBV-encoded RNA-1 in situ hybridization was performed using an antisense oligoprobe. Sections were reviewed for the presence of EBV-encoded RNA-1 in tumor cells. All 80 adenocarcinomas and 50 mesotheliomas were negative for EBV-encoded RNA-1 by in situ hybridization. In conclusion, no evidence for an etiologic role for EBV in the development of pulmonary adenocarcinoma or pleural mesothelioma was found in this study.

Fetal varicella syndrome with manifestations limited to the eye.

The manifestations of fetal varicella syndrome usually involve several organ systems, including skin, ocular, neurologic, gastrointestinal, and genitourinary. Although ocular anomalies have been reported to be as high as 68%, manifestations limited to the eyes is extremely rare. Herein we report the case of fetal varicella syndrome with no clinical signs other than esotropia and a chorioretinal scar.

1H NMR studies on bovine cyclophilin: preliminary structural characterization of this specific cyclosporin A binding protein.

High-field 1H NMR spectroscopy has been used to study the conformation of the cytosolic cyclosporin A binding protein cyclophilin. For the drug-free form of cyclophilin, spectral editing methods in conjunction with a pH titration were used to identify all four His residues present in the protein, and two-dimensional COSY and RELAY spectroscopy was used to elucidate the scalar connectivities in the aromatic and upfield methyl regions of the spectrum. From these scalar connectivities, it was possible to distinguish between inter- and intraresidue dipolar interactions within the aromatic and upfield methyl regions of cyclophilin in the NOESY spectrum. The results of this analysis showed extensive interresidue cross-relaxation among and between these latter spectral regions indicative of the proximal relationships of several of these residues and the presence of a hydrophobic core within cyclophilin.