First Measurement of a Long-Lived π

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π^{+}π^{-} atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1 µm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, n_{A}^{L}=436_{-61}^{+157}|_{tot}, the lifetime of the 2p state is found to be τ_{2p}=(0.45_{-0.30}^{+1.08}|_{tot})×10^{-11} s, not contradicting the corresponding QED 2p state lifetime τ_{2p}^{QED}=1.17×10^{-11} s. This lifetime value is three orders of magnitude larger than our previously measured value of the π^{+}π^{-} atom ground state lifetime τ=(3.15_{-0.26}^{+0.28}|_{tot})×10^{-15} s. Further studies of long-lived π^{+}π^{-} atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.

Observation of π

The observation of hydrogenlike πK atoms, consisting of π^{-}K^{+} or π^{+}K^{-} mesons, is presented. The atoms are produced by 24 GeV/c protons from the CERN PS accelerator, interacting with platinum or nickel foil targets. The breakup (ionization) of πK atoms in the same targets yields characteristic πK pairs, called "atomic pairs," with small relative momenta Q in the pair center-of-mass system. The upgraded DIRAC experiment observed 349±62 such atomic πK pairs, corresponding to a signal of 5.6 standard deviations. This is the first statistically significant observation of the strange dimesonic πK atom.

Differential effects of aging on dendritic spines in visual cortex and prefrontal cortex of the rhesus monkey.

Aging decreases the density of spines and the proportion of thin spines in the non-human primate (NHP) dorsolateral prefrontal cortex (dlPFC). In this study, we used confocal imaging of dye-loaded neurons to expand upon previous results regarding the effects of aging on spine density and morphology in the NHP dlPFC and compared these results to the effects of aging on pyramidal neurons in the primary visual cortex (V1). We confirmed that spine density, and particularly the density of thin spines, decreased with age in the dlPFC of rhesus monkeys. Furthermore, the average head diameter of non-stubby spines in the dlPFC was a better predictor than chronological age of the number of trials required to reach criterion on both the delayed response test of visuospatial working memory and the delayed nonmatching-to-sample test of recognition memory. By contrast, total spine density was lower on neurons in V1 than in dlPFC, and neither total spine density, thin spine density, nor spine size in V1 was affected by aging. Our results highlight the importance and selective vulnerability of dlPFC thin spines for optimal prefrontal-mediated cognitive function. Understanding the nature of the selective vulnerability of dlPFC thin spines as compared to the resilience of thin spines in V1 may be a promising area of research in the quest to prevent or ameliorate age-related cognitive decline.

X-ray fluorescence from the element with atomic number Z=120.

An atomic clock based on x-ray fluorescence yields has been used to estimate the mean characteristic time for fusion followed by fission in reactions 238U + 64Ni at 6.6 MeV/A. Inner shell vacancies are created during the collisions in the electronic structure of the possibly formed Z=120 compound nuclei. The filling of these vacancies accompanied by a x-ray emission with energies characteristic of Z=120 can take place only if the atomic transitions occur before nuclear fission. Therefore, the x-ray yield characteristic of the united atom with 120 protons is strongly related to the fission time and to the vacancy lifetimes. K x rays from the element with Z=120 have been unambiguously identified from a coupled analysis of the involved nuclear reaction mechanisms and of the measured photon spectra. A minimum mean fission time τ(f)=2.5×10(-18) s has been deduced for Z=120 from the measured x-ray multiplicity.

Typical and unusual sonoelastographic patterns of breast cystic lesions: impact on BI-RADS classification.

PURPOSE: To describe the sonoelastographic appearance of breast cysts (simple, complicated-cysts with sedimentation and complex-cysts with internal solid parts). To assess the influence of sonoelastography on the BI-RADS classification of complicated cysts. MATERIALS AND METHODS: A prospective study was conducted and all cysts diagnosed by the same radiologist between May 2007 and July 2008 in our breast unit were included. Each lesion was assessed according to BI-RADS and the Tsukuba elasticity score using a Hitachi 8500 US device. Cytology or histopathology was obtained for complicated and complex cysts. RESULTS: 49 simple, 43 complicated and 14 complex cysts were detected. The elasticity patterns were divided into 4 categories: typical BGR (blue-green-red) pattern, appearance similar to that described for solid. lesions, variants of BGR, an inverse score of 3. The BGR pattern was predominant in breast cysts. Atypical elasticity patterns were mostly associated with complicated and complex cysts. BI-RADS classification of complicated cysts before and after elastography showed a statistically significant difference in terms of final category assessment (most of the complicated cysts were downgraded to BI-RADS 2 after elastography). CONCLUSION: Being aware of the wide spectrum of elastographic patterns of breast cysts and considering elastography when assessing the BI-RADS category of complicated cysts may lead radiologists to better patient management.

Interactive effects of age and estrogen on cortical neurons: implications for cognitive aging.

In the past few decades it has become clear that estrogen signaling plays a much larger role in modulating the cognitive centers of the brain than previously thought possible. We have developed a nonhuman primate (NHP) model to investigate the relationships between estradiol (E) and cognitive aging. Our studies of cyclical E treatment in ovariectomized (OVX) young and aged rhesus monkeys have revealed compelling cognitive and synaptic effects of E in the context of aging. Delayed response (DR), a task that is particularly dependent on integrity of dorsolateral prefrontal cortex (dlPFC) area 46 revealed the following: (1) that young OVX rhesus monkeys perform equally well whether treated with E or vehicle (V), and (2) that aged OVX animals given E perform as well as young adults with or without E, whereas OVX V-treated aged animals display significant DR impairment. We have analyzed the structure of layer III pyramidal cells in area 46 in these same monkeys. We found both age and treatment effects on these neurons that are consistent with behavioral data. Briefly, reconstructions of pyramidal neurons in area 46 from these monkeys showed that cyclical E increased the density of small, thin spines in both young and aged monkeys. However, this effect of E was against a background of age-related loss of small, thin spines, leaving aged V-treated monkeys with a particularly low density of these highly plastic spines, and vulnerable to cognitive decline. Our current interpretation is that E not only plays a critically important role in maintaining spine number, but also enables synaptic plasticity through a cyclical increase in small highly plastic spines that may be stabilized in the context of learning. Interestingly, recent studies demonstrate that chronic E is less effective at inducing spinogenesis than cyclical E. We have begun to link certain molecular attributes of excitatory synapses in area 46 to E effects and cognitive performance in these monkeys. Given the importance of synaptic estrogen receptor α (ER-α) in rat hippocampus, we focused our initial studies on synaptic ER-α in area 46. Three key findings have emerged from these studies: (1) synaptic ER-α is present in axospinous synapses in area 46; (2) it is stable across treatment and age groups (which is not the case in rat hippocampus); and (3) the abundance and distribution of synaptic ER-α is a key correlate of individual variation in cognitive performance in certain age and treatment groups. These findings have important implications for the design of hormone treatment strategies for both surgically and naturally menopausal women. This article is part of a Special Issue entitled: Neuroactive Steroids: Focus on Human Brain.

Benign intraductal papillary-mucinous neoplasm of the pancreas associated with spontaneous pancreaticogastric and pancreaticoduodenal fistulas.

Invasive intraductal papillary-mucinous neoplasms (IPMNs) of the pancreas may be associated with pancreaticogastric fistulas as shown by case reports. We report the case of a benign IPMN associated with pancreaticogastric and pancreaticoduodenal fistulas. A 70-year-old woman was admitted with intestinal obstruction. Computed tomography and MRI showed a large dilatation of the main pancreatic duct (>1 cm) with intraductal nodules, and pancreaticogastric and pancreaticoduodenal fistulas. Several features in imaging were present to support a malignant IPMN, so that the patient underwent a pancreaticoduodenectomy. The histopathological examination of the surgical specimen showed a benign IPMN. This case proves that a benign IPMN can cause pancreaticogastric and pancreaticoduodenal fistulas, probably resulting from mechanical factors.

Health food store recommendations for breast cancer patients.

CONTEXT: Despite cancer patients' widespread and growing use of complementary and alternative medicine, minimal attention has been paid to the role of health food stores in the "supply side" of this phenomenon. OBJECTIVE: To gain a better understanding of health food store personnel's recommendations for breast cancer patient care. DESIGN: Researcher posing as the daughter of a breast cancer patient and surveying health food store personnel on their product recommendations for cancer care. SETTING: Oahu, Hawaii, summer 1998. PARTICIPANTS: All health food stores (N = 40) offering products for cancer patients. MAIN OUTCOME MEASURES: Recommended products and services, proposed mechanism of action, and costs. RESULTS: Store personnel readily provided information and product recommendations, with shark cartilage being the most frequent. Suggested mechanisms of action drew on traditional healing, scientific, and pseudoscientific rationales. Costs for recommended dosages varied multifold across stores and brands. CONCLUSIONS: Retailers supplying supplements can play an important role in the network of "authorities" for patients with breast and other cancers, as they readily provide advice and recommend products. The reasons why patients seek health food store remedies are useful in developing approaches to patient education. Physicians and other providers are in a key position to assist cancer patients in making informed choices when considering health store products.

Mechanism of action of leukotriene D4 on guinea pig tracheal smooth muscle cells: roles of Ca++ influx and intracellular Ca++ release.

The effects of leukotriene D4 (LTD4) on the concentration of intracellular cytosolic free calcium ([Ca++]i) and on phosphoinositide hydrolysis were studied in cultured guinea pig tracheal smooth muscle cells. In Fura-2-loaded cells, LTD4 (10(-9)-10(-6) M) induced concentration-dependent changes in [Ca++]i consisting of a slow, transient increase followed by a sustained phase. Preincubation of cells with LTD4 receptor antagonist MK-571 (10(-6) M) blocked the increase in [Ca++]i. Similarly, LTD4-induced inositol phosphate ([3H]InsP(s) synthesis was transient, concentration-dependent and inhibited by the LTD4 antagonist. In the absence of extracellular Ca++, LTD4 failed to induce [Ca++]i increases and [3H]InsP(s) formation. Accordingly, NiCl2 completely inhibited the LTD4-stimulated [3H]InsP(s) synthesis. Nifedipine (10(-5) M) had a slight inhibitory effect on [Ca++]i increase but significantly reduced (40-50%) the [3H]lnsP(s) accumulation. These findings indicate that LTD4-stimulated inositol phosphate synthesis and [Ca++]i increases in tracheal smooth muscle cells are receptor-mediated events and are dependent on the availability of extracellular Ca++. It is suggested that Ca++ influx plays a major role in the LTD4 signal transduction mechanism.

Bioactive polymers 68--controlled release of neomycin-furazolidone bicomponent system from xanthan hydrogel.

The neomycin-furazolidone-xanthan complex has been synthesized. Neomycin is covalently linked to xanthan, while furazolidone is inserted in the hydrogel formed by the reaction between neomycin and xanthan. The content of neomycin and furazolidone depends on the drug rate in the reaction medium. Thus, a zero-order kinetics is obtained for the release of both neomycin and furazolidone in basic medium. The complex's antimicrobial activity is intensified.

Bioactive polymers. 70. The kinetics of controlled release of neomycin in an alkaline medium.

Neomycin is coupled on xanthan--a polysaccharide of microbial biosynthesis produced by Xanthomona campestris--through ionic complexation. The kinetics of neomycin release, in vitro, at pH = 8.2 is studied. A release of neomycin, following a zero order kinetics, is observed, regardless of the eluent flow-rate. The neomycin-xanthan complex, protected by a cellulosic membrane, behaves like a monolithic-type device. Diffusion coefficients--increasing with increasing the eluent flow-rate--are also calculated.

Bioactive polymers: in vitro and in vivo study of controlled release neomycin.

Neomycin is coupled on xanthan-a polysaccharide of microbial biosynthesis produced by Xanthomonas campestris-through ionic complexation. The kinetics of neomycin release, in vitro, at pH = 8.2 is studied. A controlled release of neomycin, following a zero order kinetics is observed, regardless of the eluent flow. Neomycin complexed on xanthan, administered in a unique daily dose to patients suffering from dysentery in the 100 cases taken in study, has shown a high clinical efficiency as compared with the treatments with ampicillin or furazolidone, administered for 5-10 days or longer.

Bioactive polymers 54. Pharmacological properties of modified neomycin.

Modified neomycin prepared by the ionic coupling on xanthan with an activity of 380 UI/mg was characterized in regard to its in vitro and in vivo release rate and therapeutic action with artificial tear eluent. The dynamic system in vitro release showed that after 4 h, there appears a "zero-order" kinetic. Ophthalmic inserts were prepared from modified neomycin and they are used in treating bacterial conjunctivitis. Sterilization of the conjunctival sac is obtained 12 h after insert administration.

Bioactive polymers. LX. Kinetics of delayed release neomycin-xanthan complex.

The kinetics of delayed release neomycin-xanthan complex, and its antimicrobial activity, were studied. Delayed release neomycin (53.13% free neomycin) had zero-order release kinetics, when artificial tear solution was used as eluent. Microbiological tests revealed an activity of 380 units/mg, 10% higher than neomycin in its free form.