The nature of the hydrophobic interaction varies as the solute size increases from methane's to C60's.

The hydrophobic interaction, often combined with the hydrophilic or ionic interactions, makes the behavior of aqueous solutions very rich and plays an important role in biological systems. Theoretical and computer simulation studies have shown that the water-mediated force depends strongly on the size and other chemical properties of the solute, but how it changes with these factors remains unclear. We report here a computer simulation study that illustrates how the hydrophobic pair interaction and the entropic and enthalpic terms change with the solute size when the solute-solvent weak attractive interaction is unchanged with the solute size.

Close-Packed Ices in Nanopores.

Water molecules in any of the ice polymorphs organize themselves into a perfect four-coordinated hydrogen-bond network at the expense of dense packing. Even at high pressures, there seems to be no way to reconcile the ice rules with the close packing. Here, we report several close-packed ice phases in carbon nanotubes obtained from molecular dynamics simulations of two different water models.

Multiple angiosarcomas of both breasts: a case report.

Background: Primary angiosarcomas of the breast are rare and highly aggressive. We herein report a rare case of multiple angiosarcomas detected concurrently in both breasts.

Case Presentation: A 49-year-old woman visited a doctor after noticing a lump in her right breast.

Solvation free energies of alcohols in water: temperature and pressure dependences.

Solvation free energies * of amphiphilic species, methanol and 1,2-hexanediol, are obtained as a function of temperature or pressure based on molecular dynamics simulations combined with efficient free-energy calculation methods. In general, * of an amphiphile can be divided into and , the nonpolar and electrostatic contributions, and the former is further divided into and which are the work of cavity formation process and the free energy change due to weak, attractive interactions between the solute molecule and surrounding solvent molecules. We demonstrate that * of the two amphiphilic solutes can be obtained accurately using a perturbation combining method, which relies on the exact expressions for and and requires no simulations of intermediate systems between the solute with strong, repulsive interactions and the solute with the van der Waals and electrostatic interactions.

How do water-mediated interactions and osmotic second virial coefficients vary with particle size?

We examine quantitatively the solute-size dependences of the effective interactions between nonpolar solutes in water and in a simple liquid. The potential () of mean force and the osmotic second virial coefficients are calculated with high accuracy from molecular dynamics simulations. As the solute diameter increases from methane's to C's with the solute-solute and solute-solvent attractive interaction parameters fixed to those for the methane-methane and methane-water interactions, the first minimum of () lowers from -1.

Anaplastic lymphoma kinase-positive inflammatory myofibroblastic tumor of the breast: a case report and review of the literature.

Background: Few reports of inflammatory myofibroblastic tumor (IMT) of the breast have been published worldwide. Furthermore, primary anaplastic lymphoma kinase (ALK)-positive IMT of the breast is extremely rare. To date, only six patients with ALK-positive IMT have been reported in the literature.

Molecular mechanism of the common and opposing cosolvent effects of fluorinated alcohol and urea on a coiled coil protein.

Alcohols and urea are widely used as effective protein denaturants. Among monohydric alcohols, 2,2,2-trifluoroethanol (TFE) has large cosolvent effects as a helix stabilizer in proteins. In contrast, urea efficiently denatures ordered native structures, including helices, into coils.

Wetting and Nonwetting near a Tricritical Point.

The dihedral contact angles between interfaces in three-fluid-phase equilibria must be continuous functions of the bulk thermodynamic fields. This general argument, which we propose, predicts a nonwetting gap in the phase diagram, challenging the common belief in "critical-point wetting," even for short-range forces. A demonstration is provided by exact solution of a mean-field two-density functional theory for three-phase equilibria near a tricritical point (TCP).

Osmotic second virial coefficients for hydrophobic interactions as a function of solute size.

To gain quantitative insight into how the overall strength of the hydrophobic interaction varies with the molecular size, we calculate osmotic second virial coefficients B for hydrophobic spherical molecules of different diameters σ in water based on molecular simulation with corrections to the finite-size and finite-concentration effects. It is shown that B (<0) changes by two orders of magnitude greater as σ increases twofold and its solute-size dependence is best fit by a power law B ∝ σ with the exponent α ≃ 6, which contrasts with the cubic power law that the second virial coefficients of gases obey. It is also found that values of B for the solutes in a nonpolar solvent are positive but they obey the same power law as in water.

Theory of Gas Solubility and Hydrophobic Interaction in Aqueous Electrolyte Solutions.

Ion-specific effects on the solubility of nonpolar solutes and on the solute-solute hydrophobic interaction in aqueous electrolyte solutions are studied on the basis of a continuum theory that incorporates the excluded volume of the molecules using the four-component (water, cations, anions, and solutes) Boublı́k-Mansoori-Carnahan-Starling-Leland model and ion hydration (electrostriction) using the Born model. We examine how the ordering of ions in the salt effect on the solubility as measured by the Sechenov coefficient changes with varying sizes of ions and solutes. Our calculation reproduces the general trend of experimentally measured and also provides insight into the irregular behavior of for lithium ion.

Ion Size Dependences of the Salting-Out Effect: Reversed Order of Sodium and Lithium Ions.

A general trend of the salting-out effect on hydrophobic solutes in aqueous solution is that the smaller the size of a dissolved ion, the larger the effect of reducing the solubility of a hydrophobe. An exception is that Li, the smallest in alkali metal ions, has a notably weaker effect than Na. To understand the reversed order in the cation series, we performed molecular dynamics simulations of aqueous solutions of salt ions and calculated the Setschenow coefficient of methane with the ionic radius of either a cation or an anion varied in a wide range.

Structure and phase behavior of high-density ice from molecular-dynamics simulations with the ReaxFF potential.

We report a molecular dynamics simulation study of dense ice modeled by the reactive force field (ReaxFF) potential, focusing on the possibility of phase changes between crystalline and plastic phases as observed in earlier simulation studies with rigid water models. It is demonstrated that the present model system exhibits phase transitions, or crossovers, among ice VII and two plastic ices with face-centered cubic (fcc) and body-centered cubic (bcc) lattice structures. The phase diagram derived from the ReaxFF potential is different from those of the rigid water models in that the bcc plastic phase lies on the high-pressure side of ice VII and does the fcc plastic phase on the low-pressure side of ice VII.

Theory of electrolytes including steric, attractive, and hydration interactions.

We present a continuum theory of electrolytes composed of a waterlike solvent and univalent ions. First, we start with a density functional F for the coarse-grained solvent, cation, and anion densities, including the Debye-Hückel free energy, the Coulombic interaction, and the direct interactions among these three components. These densities fluctuate obeying the distribution ∝exp(-F/kT).

Three-phase equilibria in density-functional theory: Interfacial tensions.

A mean-field density-functional model for three-phase equilibria in fluids (or other soft condensed matter) with two spatially varying densities is analyzed analytically and numerically. The interfacial tension between any two out of three thermodynamically coexisting phases is found to be captured by a surprisingly simple analytic expression that has a geometric interpretation in the space of the two densities. The analytic expression is based on arguments involving symmetries and invariances.

Theoretical analysis on thermodynamic stability of chignolin.

Understanding the dominant factor in thermodynamic stability of proteins remains an open challenge. Kauzmann's hydrophobic interaction hypothesis, which considers hydrophobic interactions between nonpolar groups as the dominant factor, has been widely accepted for about sixty years and attracted many scientists. The hypothesis, however, has not been verified or disproved because it is difficult, both theoretically and experimentally, to quantify the solvent effects on the free energy change in protein folding.

A case of primary extraskeletal osteosarcoma of the breast.

Background: Primary sarcomas of the breast are rare and account for less than 1% of all primary breast malignancies. We experienced a case of extraskeletal osteosarcoma of the breast that had a unique clinical course and remarkable findings of mammography and magnetic resonance imaging (MRI). A review of the case reports published in the past few decades showed no reports of a case in which a calcified lesion was followed up three different times on mammography, making this a valuable case report.

[A Case of Metaplastic Squamous Cell Carcinoma of the Breast Diagnosed after Neoadjuvant Chemotherapy].

Metaplastic carcinoma is a rare type of breast carcinoma, which tends to be chemo-resistant. We report a case of metaplastic squamous cell carcinoma of the breast diagnosed after neoadjuvant chemotherapy(NAC). A 56-year-old woman was diagnosed as having right-sided breast cancer(invasive ductal carcinoma[IDC], triple negative), cT1cN1M0, stage II A.

Upstaging to invasive ductal carcinoma after mastectomy for ductal carcinoma in situ: predictive factors and role of sentinel lymph node biopsy.

Background: The aim of this study was to investigate preoperative factors associated with ductal carcinoma in situ (DCIS) upstaged to invasive ductal carcinoma (IDC) and sentinel lymph node (SLN) status in patients who underwent mastectomy for a preoperative diagnosis of DCIS.

Methods: The medical records of 220 patients who underwent mastectomy for a preoperative diagnosis of DCIS were retrospectively reviewed.

Results: Fifty-one (22.

Diagnosis, characteristics, and treatment of breast carcinomas within benign fibroepithelial tumors.

Background: Breast carcinoma arising in a benign fibroepithelial tumor is rare, and is usually discovered incidentally during examination of the breast mass.

Methods: We evaluated the clinicopathological features, treatment, and prognosis of seven women with breast carcinomas within benign fibroepithelial tumors, diagnosed and treated at a single institution between 2011 and 2015.

Results: Seven women, aged 21-64 years, visited our hospital complaining of a breast mass detected by self-checking or screening examination.

Application of reference-modified density functional theory: Temperature and pressure dependences of solvation free energy.

Recently, we proposed a reference-modified density functional theory (RMDFT) to calculate solvation free energy (SFE), in which a hard-sphere fluid was introduced as the reference system instead of an ideal molecular gas. Through the RMDFT, using an optimal diameter for the hard-sphere reference system, the values of the SFE calculated at room temperature and normal pressure were in good agreement with those for more than 500 small organic molecules in water as determined by experiments. In this study, we present an application of the RMDFT for calculating the temperature and pressure dependences of the SFE for solute molecules in water.

Influence of co-non-solvency on hydrophobic molecules driven by excluded volume effect.

We demonstrate by molecular dynamics simulation that co-non-solvency manifests itself in the solvent-induced interaction between three hydrophobes, methane, propane and neopentane, in methanol-water mixtures. Decomposition of the potential of mean force, based on the potential distribution theorem, clearly shows that the solute-solvent entropic change is responsible for stabilizing the aggregation of these hydrophobic molecules. Furthermore, we show that the entropic change pertains to the excluded volume effect.