Nucleation and Growth of the Supercooled Liquid Phase Control Glass Transition in Bulk Ultrastable Glasses.

We report the anomalous bulk transformation of vapor deposited stable glasses into the liquid state. The transformation proceeds through two competing parallel processes: partial rejuvenation of the stable glass and nucleation and growth of liquid patches within the glass. The kinetics of the transformation extracted from heat capacity curves after isothermal runs is dominated by the heterogeneous nucleation and growth process that initiates at preexisting seeds and propagates radially at a velocity proportional to the alpha relaxation time. Remarkably, the distance between the activation seeds is independent of temperature within experimental uncertainty and amounts to several micrometers, a value in close agreement with the crossover length for TPD glasses. We speculate the initiation sites for the transformation of the glass into the supercooled liquid are localized regions of lower stability (or density).

Multiple glass transitions in vapor-deposited orientational glasses of the most fragile plastic crystal Freon 113.

We investigate by fast-scanning nanocalorimetry the formation of Freon 113 films from the vapor phase at deposition temperatures ranging from 50 to 120 K, that is, spanning above and below the transition temperature of the glassy crystal to the plastic crystal (Tgc = 72 K). Analysis of the heat capacity curves indicates that vapor deposition at T < Tgc of the highly fragile Freon 113 yields structural and orientational glasses in the as-deposited state depending on the temperature range of deposition. Interestingly, growing above Tgc produces plastic crystals with a conformational ratio C1/Cs that changes with Tdep above and below 110-120 K, the temperature at which previous works have identified the arrest of the transformations between the C1 and Cs conformers.

Relaxation dynamics of glasses along a wide stability and temperature range.

While lots of measurements describe the relaxation dynamics of the liquid state, experimental data of the glass dynamics at high temperatures are much scarcer. We use ultrafast scanning calorimetry to expand the timescales of the glass to much shorter values than previously achieved. Our data show that the relaxation time of glasses follows a super-Arrhenius behaviour in the high-temperature regime above the conventional devitrification temperature heating at 10 K/min. The liquid and glass states can be described by a common VFT-like expression that solely depends on temperature and limiting fictive temperature. We apply this common description to nearly-isotropic glasses of indomethacin, toluene and to recent data on metallic glasses. We also show that the dynamics of indomethacin glasses obey density scaling laws originally derived for the liquid. This work provides a strong connection between the dynamics of the equilibrium supercooled liquid and non-equilibrium glassy states.

Infection and immunity on a chip: a compartmentalised microfluidic platform to monitor immune cell behaviour in real time.

Cells respond to their environments and self-organise into multicellular assemblies with dedicated functions. The migratory and homing response of cells to soluble ligands can be studied by using different techniques, but for real time studies of complex multicellular self-organisation, novel and simpler systems are required. We fabricated a flexible open access microsystem and tested the design by studying cell recruitment from an immune cell reservoir towards an infectious compartment. The two compartments were connected by a network of bifurcated microchannels allowing diffusion of signalling molecules and migration of cells. Bacterial filters were incorporated in the design to prevent bacteria and activated cells from entering the network, permitting migration only from the recruitment reservoir. The fabricated microsystem allows real-time continuous monitoring of cellular decision-making based on biologically produced gradients of cytokines and chemokines. It is a valuable tool for studying cellular migration and self-organisation in relation to infections, autoimmunity, cancer, stem cell homing, and tissue and wound repair.

Hamartoma of mature cardiac myocytes.

The clinical and pathological findings of three patients with hamartomas of mature cardiac myocytes resembling localized hypertrophic cardiomyopathy are presented. Hypertrophic cardiomyopathy is manifest by a poorly demarcated area of cardiac hypertrophy, microscopically demonstrating myofiber disarray and intramural coronary thickening. Localized, nonencapsulated masses of hypertrophied cardiac myocytes in locations other than the left ventricle or ventricular septum have not been reported. The clinical and pathological data of three patients with localized hamartomas were retrospectively retrieved. The patients were 9, 22, and 28 years old, respectively; none had a known family history of heart disease or cardiomyopathy. Two patients had cardiac arrhythmias: one patient died suddenly, and one patient had the Wolff-Parkinson-White syndrome. The third patient was asymptomatic. Two patients treated surgically had single masses in the right atrium and right ventricle, respectively. The patient who died suddenly had multiple discrete masses throughout the atrial and ventricular myocardium, including the left ventricular free wall. None of the three patients had septal asymmetry suggestive of hypertrophic cardiomyopathy. Histologically, there were discrete but unencapsulated nodules of marked myocyte hypertrophy with disorganization, focal scarring, and thickened intramural arteries. There was no myocyte vacuolization suggestive of cardiac rhabdomyoma. Ultrastructurally, the myocytes showed abundant and disorganized myofilaments and normal intercellular junctions. Hamartoma of mature cardiac myocytes is a previously undescribed cardiac tumor that shares some features of hypertrophic cardiomyopathy and rhabdomyoma, but is currently best considered a separate entity.

The normal and pathologic ischiorectal fossa at CT and MR imaging.

A wide spectrum of disease processes involve the ischiorectal fossa, including congenital and developmental lesions; inflammatory, traumatic, and hemorrhagic conditions; primary tumors; and pathologic processes outside the ischiorectal fossa with secondary involvement. Both computed tomography (CT) and magnetic resonance (MR) imaging are useful in the definitive diagnosis of these pathologic conditions, with MR imaging being the modality of choice because of its superior contrast resolution and multiplanar capability. In Gartner duct cyst, both CT and MR imaging demonstrate a well-defined, round mass; in tailgut cyst, CT demonstrates a well-defined retrorectal mass with a solid or cystic appearance. MR imaging in particular plays a major role in the assessment of fistula in ano, infection, and hematoma. Lipoma and pelvic plexiform neurofibroma typically have low attenuation and high signal intensity at CT and MR imaging, respectively. Recurrent rectal tumor appears at both modalities as an irregular soft-tissue mass with or without central necrosis in the presacral space, perineum, or pelvic sidewall. Familiarity with the imaging features and differential diagnoses of various ischiorectal pathologic processes will facilitate prompt, accurate diagnosis and treatment.

PET scans of abdominal malignancy.

Positron emission tomography (PET) with fluorine-18-2-d-deoxyglucose (FDG) currently is being integrated into clinical oncology because it provides unique functional information that can be applied to the management of cancer. In particular, it is useful for assessing tumor activity and growth, evaluating efficacy of therapy, and detecting tumor recurrence. Studies have demonstrated the value of whole-body PET-FDG imaging when staging and managing abdominal malignancy.

Fatal flecainide intoxication.

Two fatalities resulting from suicidal ingestion of flecainide are described. The decedents, ages 33 and 15, were otherwise healthy; both took their mothers' medications. In one case, from electrocardiographic data, there was found a high-grade conduction block with idioventricular rhythm. Blood and tissue samples from autopsy were analyzed for flecainide by gas chromatography/nitrogen-phosphorous detection and gas chromatography/mass spectrometry. Blood concentrations of 93.7 and 100 mg/L flecainide were found.

Blows to the maternal abdomen causing fetal demise: report of three cases and a review of the literature.

Traumatic abruption results in 6% of third-trimester gravidas who are hit or kicked in the abdomen during assaults. Three cases are presented in which blows inflicted to the abdomen of pregnant women in their third trimester resulted in the death of the fetus due to abruptio placentae. Two cases were domestic altercations while one was a third-party criminal assault. In all cases the gravida herself escaped significant intra-abdominal injury, and external abdominal findings were minimal. The clinical signs were a history of loss of fetal movements shortly after the assault and loss of fetal heart tones within hours after the assault. One patient had vaginal bleeding; one had uterine contractions. In the cases of domestic abuse, both women initially gave false histories of how the injury occurred.

Ureteroscopic management of ureteral cholesteatoma.

Cholesteatoma of the upper urinary tract is a rare nonmalignant condition histologically characterized by keratinized desquamative squamous metaplasia. Most cases have been managed by extensive ablative surgery. We describe a new approach in the diagnosis and management of a patient with ureteral cholesteatoma using transurethral ureteroscopy and evacuation.

Fatal massive hepatic necrosis: a probable hypersensitivity reaction to sulfasalazine.

Sulfasalazine (salicylazosulfapyridine) is a commonly prescribed oral medication for inflammatory bowel disease. We report a case of a 15-yr-old boy with ulcerative colitis who developed a generalized hypersensitivity reaction with a serum sickness-like syndrome and severe hepatotoxicity while taking sulfasalazine, perphenazine, and amitriptyline. The injury to the liver persisted for 5 months after withdrawal of the drugs, and the patient died of terminal hepatic failure with massive hepatic necrosis. Severe hepatic toxicity to sulfasalazine is uncommon, but it can be fatal.