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The morphology of calcium oxalate monohydrate (COM) kidney stones is studied using polarized light microscopy and X-ray diffraction. We show that polycrystalline structure of COM stones exhibits spherulitic texture where the arrangement of crystallites indicates that their fast growth direction is perpendicular to the corresponding radius of spherulite, resulting in the layered morphology. This is in contrast to “normal” spherulites, where the crystal growth process leads to the formation of a radiating array of fiber crystallites. We demonstrate that COM stones consist of spherulitic domains. The domains have the shape of comparatively narrow randomly distorted cones in which the crystallites form strong texture, so that their crystallographic axes have almost the same directions and the [100] crystallographic planes are nearly perpendicular to the radial direction of the domain. However, the order among the domains does not exist. Deviations of their radial directions from the corresponding radial direc...

Here we report the amount and location of fluid water absorbed by calcium oxalate monohydrate (COM) kidney stones evaluated using controlled humidity and magnetic resonance imaging (MRI). COM stones subjected to rehydration in a controlled humidity chamber for 16 h at 37 °C absorb approximately 3 wt % water, most of which resides only in thin outer shells of the stones and not within their cores. Although scanning electron microscopy (SEM) shows that there are differences in texture between the inner surface of the water-absorbing shell and the outer surface of the nonabsorbing core, energy-dispersive X-ray (EDX) spectroscopy does not reveal any differences in elemental composition between the two surfaces, and X-ray diffraction (XRD) of powered samples shows them to be similar in crystalline nature. The fact that COM stones do not absorb a significant amount of fluid water beyond their thin outer coatings, which have a different (albeit unidentified) interfacial material separating them from the bulk of ...

A novel hybrid system (Zn4) containing a zinc bis(acylamidine) fluorescent dye covalently decorated with two photochromic dithienylethene (DTE) structures was prepared using a concise synthetic route. The photoregulated quenching of the fluorescence from the metal complex was achieved by reversibly switching the DTE component between its two isomers using UV and visible light. The fluorescence quenching can be attributed to intramolecular energy transfer, electron transfer or a combination of the two. Either process is only possible when the DTE is in its ring-closed form (Zn4b). The ring-open counterpart (Zn4a) lacks an absorption band in the visible region of the spectrum to accommodate energy transfer from the metallobis(acylamidine) to the photochromic DTE, and has an oxidation potential that is too large to match the reduction potential of the metal complex making electron transfer thermodynamically unfavourable. UV–vis absorption and emission spectroscopy demonstrated that the photoregulation of fluorescence has little effect on the photochromic process and the fluorescence could be turned “on” and “off” several times without the appearance of notable side products. The high contrast ratio (∼100:1) between the bright and dark states combined with the excellent thermal bistability make the hybrid an excellent candidate for potential use in non-destructive read-out and biological labeling applications, although several limitations need to be overcome (speed of photoswitching, and stability and solubility in water).

Control over interfacial properties in organic photovoltaics (OPVs) is critical for many aspects of their performance. Functionalization of the transparent conducting electrode, in this case, indium tin oxide (ITO), through an electrostatic layer by layer (eLbL) approach with cationic N,N-bis[2-(trimethylammonium)ethylene] perylene-3,4,9,10-tetracarboxyldiimide (PTCDI +) and anionic poly(3,4-ethylenedioxythiophene):poly(p- styrenesulfonate) (PEDOT:PSS -), led to high control over the surface properties. The films were studied through a variety of surface and spectroscopic techniques, including X-ray photoelectron spectroscopy (XPS), UV-visible spectroscopy, atomic force microscopy (AFM), and ellipsometry. The work function of modified ITO was measured by UV photoelectron spectroscopy (UPS) and showed oscillating values with respect to odd-even layer numbers; the strong odd-even effect is due to the differing electronic characteristics of the top layer, either PTCDI + or PEDOT:PSS -. The modified ITO electrodes were then used as the cathode in a series of inverted organic photovoltaic architectures. The performance of inverted OPVs was, in parallel to the UPS results, found to be highly dependent on the layer number of coated films and showed an obvious oscillation based on layer number. Inverted OPVs were retested after 128 days of storage in air, and almost all devices maintained over 70% of original power conversion efficiency (PCE). © 2011 American Chemical Society.

Using light to modulate biochemical agents in living organisms has a significant impact on photodynamic therapy and drug release. We demonstrate that a photoresponsive system can reversibly induce paralysis in nematodes as a model for living organisms when two different wavelengths of light are used to toggle the molecular switch between its two structural forms. This example illustrates how photoswitches offer great potential for advancing biomedical technologies.

Glucocorticoid therapy is often associated with impaired insulin sensitivity and cardiovascular disease. The present study was designed to evaluate cardiac fatty acid (FA) composition and metabolism following acute dexamethasone (Dex) treatment. Using the euglycemic hyperinsulinemic clamp, rats injected with Dex demonstrated a reduced glucose infusion rate. This whole body insulin resistance was also associated with a heart-specific increase in pyruvate dehydrogenase kinase 4 gene expression and a reduction in the rate of glucose oxidation. Dex treatment increased basal and postheparin plasma lipolytic activity. In the heart, palmitic and oleic acid levels were higher after 4 h of Dex and decreased to control (CON) levels within 8 h. Measurement of polyunsaturated FAs demonstrated a drop in linoleic and γ-linolenic acid, with an increase in arachidonic acid (AA) after acute Dex injection. Tissue FA can be either oxidized or stored as triglyceride (TG). At 4 h, Dex augmented cardiac TG accumulation. However, this increase in tissue TG could not be maintained, such that at 8 h following Dex, TG declined to CON levels. AMP-activated protein kinase (AMPK) activation is known to promote FA oxidation through its control of acetyl-CoA carboxylase (ACC). Acute Dex promoted ACC phosphorylation, and increased cardiac palmitate oxidation, likely through its effects in increasing AMPK phosphorylation and total AMPK protein and gene expression. Whether these acute effects of Dex on FA oxidation, TG storage, and arachidonic acid accumulation can be translated into increased cardiovascular risk following chronic therapy has yet to be determined.

Human U251MG glioma cells retrovirally transduced with the human gene for the membrane form of macrophage colony-stimulating factor (mM-CSF) were investigated. The clones, MG-2F11 and MG-2C4, that expressed the most mM-CSF, but not the viral vector or the parental U251MG cells, were killed by both murine and human monocyte/macrophages in cytotoxicity assays. MG-2F11 cells failed to form subcutaneous tumors in either nude or NIH-bg-nu-xidBR mice, while mice inoculated with the U251MG viral vector (MG-VV) cells developed tumors. Electron microscopy studies showed that 4 hours after subcutaneous injection, the mM-CSF-transduced cells began dying of a process that resembled paraptosis. The dying tumor cells were swollen and had extensive vacuolization of their mitochondria and endoplasm reticulum. This killing process was complete within 24 hours. Macrophage-like cells were immediately adjacent to the killed MG-2F11 cells. Immunohistological staining for the heat shock proteins HSP60, HSP70 and GRP94 (gp96) showed that 18 hours after inoculation into nude mice, the MG-2F11 injection site was two to four times more intensely stained than the MG-VV cells. This study shows that human gliomas transduced with mM-CSF have the potential to be used as a safe live tumor cell vaccine.

Cloned T9 glioma cells (T9-C2) expressing the membrane form of macrophage colony stimulating factor (mM-CSF) inoculated subcutaneously into rats do not grow and glioma-specific immunity is stimulated. Immunotherapy experiments showed that intracranial T9 tumors present for one to four days could be successfully eradicated by peripheral vaccination with T9-C2 cells. CD4+ and CD8+ T splenocytes from immunized rats, when restimulated in vitro with T9 cells, produced interleukin-2 and -4. Protective immunity against intracranial T9 gliomas could only be adoptively transferred into naive rats by the CD4+ splenocytes obtained from T9-C2 immunized rats. Rats immunized by the T9-C2 tumor cells also resisted two different syngeneic gliomas (RT2 and F98) but allowed a syngeneic NUTU-19 ovarian cancer to grow. Such cross-protective immunity against unrelated gliomas suggests that mM-CSF transfected tumor cells have immunotherapeutic potential for use as an allogeneic tumor vaccine.