Towards dark current suppression in metallic photocathodes by selected-area oxidation.

Oxide-free surfaces of polycrystalline Cu are prepared using acetic acid etching after chemical-mechanical polishing. UV ozone treatment is shown to increase the work function of the cleaned Cu by up to 0.5 eV. There is also a large reduction in quantum efficiency at 265 nm. Cu sheet can be easily masked from ozone exposure by Si or glass, meaning that selected-area oxi-dation is possible. Oxygen plasma treatment has a similar effect to the UV ozone but is more difficult to mask. There is no increase in surface roughness after oxidation, meaning that the larger work function could significantly re-duce dark current in accelerator photocathodes without affecting the desired photoemission region.

The measurement of photocathode transverse energy distribution curves (TEDCs) using the transverse energy spread spectrometer (TESS) experimental system.

The minimum achievable particle beam emittance in an electron accelerator depends strongly on the intrinsic emittance of the photocathode electron source. This is measurable as the mean longitudinal and transverse energy spreads in the photoemitted electron beam (MLE and MTE respectively); consequently, MLE and MTE are notable figures of merit for photocathodes used as electron sources in particle accelerators. The overall energy spread is defined by the sum of the MTE and the MLE, and the minimization of MTE is crucial to reduce emittance and thus generate a high-brightness electron beam. Reducing the electron beam emittance in an accelerator that drives a Free-Electron Laser (FEL) delivers a significant reduction in the saturation length for an x-ray FEL, thus reducing the machine's construction footprint and operating costs while increasing the x-ray beam brightness. The ability to measure the transverse energy distribution curve of photoelectrons emitted from a photocathode is a key enabler in photocathode research and development that has prompted the Accelerator Science and Technology Centre (ASTeC) at the STFC Daresbury Laboratory to develop the Transverse Energy Spread Spectrometer to make these crucial measurements. We present details of the design for the upgraded TESS instrument with measured data for copper (100), (110), and (111) single-crystal photocathodes illuminated at UV wavelengths around 266 nm.

Special article: chronic granulomatous disease in the United Kingdom and Ireland: a comprehensive national patient-based registry.

There are no epidemiological studies from the British Isles of chronic granulomatous disease, characterized by recurrent, life-threatening bacterial and fungal infections and inflammatory sequelae. Patients were enrolled in a national registry and medical records were analysed. Of 94 subjects, 69 had X-linked disease, 16 had autosomal recessive disease and nine were unknown. Prevalence was 7.5/million for 1990-99 and 8.5/million for 1980-89. Suppurative adenitis, abscesses and pneumonia presented commonly. Twenty-three of 30 patients who underwent high resolution computerized tomography had chronic respiratory disease. Inflammatory sequelae included bowel stricture and urogenital tract granulomata. Growth failure was common; 75% of those measured were below the population mean. All patients received prophylactic antibiotics and 93% anti-fungal prophylaxis. Interferon gamma was used to treat infection, but rarely as prophylaxis. Despite prophylaxis, estimated survival was 88% at 10 years but 55% at age 30 years. Morbidity remains significant, severe infectious complications common. Curative treatments including stem cell transplantation should be considered for patients with frequent or serious complications.

Measurement of the longitudinal energy distribution of electrons in low energy beams using electrostatic elements.

The Transverse Energy Spread Spectrometer (TESS) was designed primarily to study the mean transverse energy spread of electrons emitted from photocathode electron sources at both room and liquid nitrogen temperatures as a function of quantum efficiency through analysis of the photoemission footprint. By reconfiguring the potentials applied to different detector elements, TESS can also be used to measure the mean longitudinal energy spread of photoemitted electrons. Initial plans were to use electrostatic wire meshes as a retarding element which prevents the detection of electrons with insufficient energy to overcome a variable potential barrier. However, this method has proved impractical and a new method has been proposed in which the photocathode bias potential is swept (effectively from a state of no electron emission to full emission) and the emitted photocurrent is then detected by using a photoemitted charge collector. In this article, we present the TESS set-up and analyze this new method to measure the longitudinal energy distribution curve. Experimental results are presented and compared to simulated results by utilising a custom designed tracking code.

Oral contraceptives for functional ovarian cysts.

BACKGROUND: Functional ovarian cysts are a common gynecological problem among women of reproductive age worldwide. When large, persistent, or painful, these cysts may require operations, sometimes resulting in removal of the ovary. Since early oral contraceptives were associated with a reduced incidence of functional ovarian cysts, many clinicians inferred that birth control pills could be used to treat cysts as well. This became a common clinical practice in the early 1970s. OBJECTIVES: This review examined all randomized controlled trials that studied oral contraceptives as therapy for functional ovarian cysts. SEARCH STRATEGY: We searched the computer databases of CENTRAL, PubMed, POPLINE, and EMBASE for randomized controlled trials. We also examined the reference lists of articles and wrote to authors of all studies identified to seek articles we had missed. SELECTION CRITERIA: We included randomized controlled trials in any language that included oral contraceptives used for treatment and not prevention of functional ovarian cysts. Criteria for diagnosis of cysts were those used by authors of studies. DATA COLLECTION AND ANALYSIS: Two authors independently abstracted data from the articles and entered them into RevMan 4.2. We used Peto odds ratios with 95% confidence intervals for dichotomous outcomes. MAIN RESULTS: We identified four randomized controlled trials from three countries; the studies included a total of 227 women. Treatment with combined oral contraceptives did not hasten resolution of functional ovarian cysts in any trial. This held true for cysts that occurred spontaneously as well as those that developed after ovulation induction. Most cysts resolved without treatment within a few cycles; persistent cysts tended to be pathological (e.g., endometrioma or para-ovarian cyst) and not physiological. AUTHORS' CONCLUSIONS: Although widely used for treating functional ovarian cysts, combined oral contraceptives appear to be of no benefit. Watchful waiting over several cycles is appropriate. Should cysts persist, surgical management is often indicated.

Effect of oxygen adsorption on the chiral Pt{531} surface.

The adsorption of oxygen on the chiral Pt{531} surface was studied by high-resolution X-ray photoelectron spectroscopy (HRXPS) and low energy electron diffraction (LEED). After the surface is annealed in oxygen (3 x 10(-7) mbar), three O 1s peaks are observed in XPS. One peak, at 529.5 eV, is assigned to chemisorbed oxygen; it disappears after annealing in vacuo to temperatures above 900 K. The other two peaks at 530.8 and 532.3 eV are stable up to at least 1250 K. They are associated with oxide clusters on the surface. These clusters readily react with coadsorbed carbon monoxide at temperatures between 315 and 620 K.

Effects of prazosin therapy on BP, renal function, and body fluid composition.

To our knowledge, the long-term effects of prazosin hydrochloride, an alpha 1-adrenoceptor antagonist, on renal function and body fluid composition have not been previously reported. Fourteen hypertensive men in whom the BP was normalized with prazosin monotherapy, underwent assessment of renal function and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) therapy. Neither short- nor long-term prazosin therapy had any adverse effect on the glomerular filtration rate or effective renal plasma flow. Renal vascular resistance was decreased 14% during short-term therapy, but not during long-term therapy. Urine flow rate, urine osmolality, free water clearance, and fractional sodium and potassium excretions were statistically unchanged throughout drug therapy. Plasma volume and extracellular fluid volume were increased following both short- and long-term therapy. Long-term prazosin monotherapy effectively lowers BP without resulting in drug tolerance, however, sodium retention probably limits its antihypertensive effectiveness.

Effects of indoramin therapy on BP, renal function, and body fluid composition.

Indoramin hydrochloride is a new alpha 1-adrenoceptor antagonist. Eleven hypertensive men in whom the BP was normalized with indoramin underwent assessment of renal function, renal hemodynamics, and body fluid composition following short-term (three to six weeks), long-term (five to six months), and withdrawal (two weeks) therapy. Short-term indoramin therapy produced a 28% increase in glomerular filtration rate, a 24% increase in effective renal plasma flow, and a 31% decrease in renal vascular resistance. Although urine flow rate and free water clearance were unchanged, fractional sodium excretion decreased 38%. Long-term indoramin therapy was associated with qualitatively similar renal effects, but the changes did not achieve statistical significance. Plasma volume was increased only during short-term therapy; however, body weight was increased following both short- and long-term therapy. Indoramin effectively lowers BP without producing deleterious renal effects.

Taste fiber responses during reinnervation of fungiform papillae.

Crushing or transecting the chorda tympani nerve of the gerbil (Meriones unguiculatus) caused ipsilateral degeneration of taste buds in the fungiform papillae. In less than two weeks some taste fibers regenerated into the tongue and formed new taste buds and receptor cells. The recovery process was evaluated electrophysiologically in 53 gerbils by acute recording proximal to the nerve injury site. Initially the chorda tympani was electrically silent. In gerbils tested at later times spontaneous activity appeared. This was followed by responses to pressure on the tongue. Taste responses returned as early as day 11. The receptive field of regenerated taste fibers was limited to a small number of fungiform papillae. Taste responses were always associated with the presence of one or more taste buds in the receptive field. Taste buds identified as responsive to chemicals contained some fusiform cells. We found that the taste responses of single fiber, few-fiber and multi-unit preparations reflected the diversity of responses found in normal taste axons as determined by recording from 26 normal single fibers and 27 normal whole nerves. The early emergence of a variety of fiber types and responses to many chemicals in regeneration is inconsistent with the proposition that the relative chemical responsiveness of a receptor cell is strictly a function of its age; the response of a given young taste receptor is not necessarily limited to a few of the standard taste stimulants.

Anthropometry of Mexican-American migrant children in northern California.

Anthropometric data were obtained from 209 Mexican-American migrant children, aged 0 to 7 yr, in the Sacramento Valley of California. Hematocrit was measured for 170 children. Only 13 children (7.6%) had hematocrits below acceptable levels. Weight-for-age, height-for-age, and weight-for-height growth percentiles approximated the National Center for Health Statistics standards. Only 15% of the children were at or below the 10th percentile of height-for-age, and only 7% were above the 95th percentile of weight-for-height, in contrast to earlier studies of Mexican-American children. The mean percentile of weight-for-height increased significantly with age, while height-for-age decreased. The rate of growth in weight and height accelerated during their summer residence in the US, indicating that the adequate growth status of these children may be related to improved conditions for growth while in the US.

Recent cytoarchitechtonic changes in the prefrontal cortex of schizophrenics.

A variety of lines of converging evidence implicate the prefrontal cortex (PFC) in schizophrenia. In the past studies have focused on the various neurotransmitter systems that appear to be involved in schizophrenia such as dopamine, glutamate and serotonin. Recently, the focus of research has shifted away from systems and towards cellular morphology due partly to studies suggesting an increase in neural density in various regions of the PFC (1,2). A plethora of research has come out suggesting possible cytoarchitectural changes in pyramidal cells in the prefrontal cortex as well as alterations of certain GABAergic cells. This review examines the recent data that shows cytoarchitechtonic changes in cells of the prefrontal cortex.

Voicing judgements by chinchillas trained with a reward paradigm.

Experiments were performed to replicate and extend previous findings of similar categorization of voiced/voiceless consonant-vowel (CV) syllables by humans and chinchillas. A reward paradigm was applied to the question of how stimulus range affects the voice-onset-time (VOT) corresponding to the voiced/voiceless category boundary. Each of four adult chinchillas and four human subjects identified synthetic CV syllables as voiced (/ba/, /da/, /ga/) or voiceless (/pa/, /ta/, /ka/) using voiceless standards of either 80 or 120 ms. In both humans and animals, extending the VOT range from 80 to 120 ms shifted category boundaries to longer VOTs, but to a different extent across listeners. Control experiments suggested that listeners were attending to different phonetic cues in a manner that depended on the listener, rather than on species. The results are interpreted in terms of similar contextual effects and use of multiple phonetic cues to voicing in humans and animals.

The effect of nerve stump length upon mammalian taste responses.

A decline in the magnitude of the summated responses evoked by taste solutions began about 1 h following IXth nerve transection. In 41 IXth nerves transected at different lengths we found a linear relationship between the length of the IXth nerve stump remaining attached to the tongue and the time for the taste response amplitude to fall to 50% of its control magnitude. The existence of a nerve stump length dependency suggests that IXth nerve taste responses in the gerbil are maintained by the axonal transport of trophic substances to the tongue.

Axonal transport maintains taste responses.

Transection of the gerbil's IXth nerve causes gustatory action potentials to decline in 1-6 h; the rate of decline is a linear function of the length of the nerve stump remaining attached to the tongue. To test the implication that taste discharge mechanisms depend upon axonal transport in the IXth nerve, we injected 40 nl of [3H]leucine into the petrosal ganglion of one IXth nerve of the gerbil, Meriones unguiculatus. Subsequent liquid scintillation counting of the petrosal ganglion, IXth nerve segments, and representative areas of the tongue indicated that labeled materials were transported down the IXth nerve primarily to the vallate and ipsilateral foliate taste papillae of the tongue. A significant impairment of axonal transport and a substantial decline in summated IXth nerve taste responses occurred within 2-3 h after colchicine was applied to the IXth nerve trunk between the tongue and the petrosal ganglion. Similarly, cooling the IXth nerve with a 3-10 degrees C thermocouple junction or metal probe impaired axonal transport and caused a taste response decline. Since impulse mechanisms of the nerve trunk continued to function distal to these sites of treatment, we concluded that the maintenance of taste discharges at the level of the taste bud depends upon unimpeded axonal transport.

The interstitial nuclei of the human anterior hypothalamus: an investigation of sexual variation in volume and cell size, number and density.

The four interstitial nuclei of the anterior hypothalamus (INAH) have been considered as candidate human nuclei for homology with the much studied sexually dimorphic nucleus of the preoptic area of the rat. Assessment of the INAH for sexual dimorphism has produced discrepant results. This study reports the first systematic examination of all four INAH in the human for sexual variation in volume, neuronal number and neuronal size. Serial Nissl-stained coronal sections through the medial preoptic area and anterior hypothalamus were examined from 18 males and 20 females who died between the ages of 17 and 65 without evidence of hypothalamic pathology or infection with the human immunodeficiency virus. A computer-assisted image-analysis system and commercial stereology software package were employed to assess total volume, neuronal number and mean neuronal size for each INAH. INAH3 occupied a significantly greater volume and contained significantly more neurons in males than in females. No sex differences in volume were detected for any of the other INAH. No sexual variation in neuronal size or packing density was observed in any nucleus. The present data corroborate two previous reports of sexual dimorphism of INAH3 but provide no support for previous reports of sexual variation in other INAH.

Colchicine reduces myelin thickness and axoplasm volume.

A Silastic cuff containing either colchicine (1% w/v) or no colchicine was placed around the lingual disorder tympani nerve of the Mongolian gerbil. After 3 days of exposure to colchicine, the mean period of the myelin sheaths was 23% less than the period observed in nerves treated with cuffs lacking colchicine, while the average number of lamellae was unaltered. At the same time colchicine reduced the volume of axoplasm by an average of 19%, an effect which was independent of fiber diameter.

Comparative studies: enalapril versus hydrochlorothiazide as first-step therapy for the treatment of primary hypertension.

Thirty-nine patients were entered into a 12-week, randomized, double-blind, parallel protocol to assess the safety and efficacy of enalapril (MK-421, 10 to 20 mg bid), hydrochlorothiazide (HCTZ, 25 to 50 mg bid), or combined drug therapy (MK-421 + HCTZ) for the treatment of primary hypertension. Specifically monitored were the effects of each drug program on BP and pulse, serum chemistries, body fluid composition and weight, renal function, and the renin-angiotensin-aldosterone axis. Results indicate that MK-421, HCTZ, and combined therapy were equally effective in lowering BP; none of the therapies significantly altered glomerular filtration rate or effective renal plasma flow. Patients on MK-421 experienced no change in volume, an increase in plasma potassium, no change in fractional sodium or potassium excretion, and a decreased urine osmolality associated with an enhanced free-water clearance. Plasma renin activity was increased, plasma angiotensin II was decreased, and plasma aldosterone was unchanged. In contrast, patients on HCTZ developed volume contraction, hypokalemia associated with an increase in fractional sodium and potassium excretion, and an increased urine osmolality associated with a decreased free-water clearance. Plasma renin activity was increased, however, plasma angiotensin II and plasma aldosterone were unchanged. Patients on combined therapy with MK-421 + HCTZ demonstrated qualitatively similar changes in serum chemistries, body fluid volumes, and renal function compared with patients receiving HCTZ alone, whereas changes in the renin-angiotensin-aldosterone system in these patients were qualitatively similar, but more marked, compared with those occurring in patients receiving MK-421 alone. We conclude that MK-421 is an effective first-step antihypertensive agent that does not produce adverse metabolic, volume, or renal effects.

Octamer-primed cycle sequencing using dye-terminator chemistry.

Octamer Sequencing Technology, OST, is a method of DNA sequencing using single octamer oligonucleotides to prime cycle sequencing reactions. This sequencing strategy is faster than a traditional primer-walking strategy, since access to this optimized octamer library eliminates delays associated with designing and synthesizing gene specific primers. In this report, OST has been optimized for fluorescent, dye-terminator cycle sequencing reactions to facilitate parallel processing of samples. The successful adaptation of OST to an automated sequencing platform and the design of and access to an octamer library are critical steps towards developing an efficient 'closed-loop' DNA sequencing system.

Octamer-primed cycle sequencing: design of an optimized primer library.

This paper describes a novel method of primer walking using octamer oligonucleotides to prime DNA sequencing reactions. Octamer sequencing is compatible with isotopic and fluorescent sequencing chemistry, reaction conditions are optimized such that the samples can be processed in parallel, and the procedure has the potential to be automated. This strategy is faster than the traditional primer walking sequencing strategy, as the existence of a primer library allows immediate access to a primer for the next sequencing reaction, eliminating delays associated with designing and synthesizing gene-specific primers. The octamer library is comprised of optimized sequencing primers, such that octamer sequencing yields results equivalent to or better than traditional primer walking. This technology is more economical because gene-specific sequencing primers, the major cost in the reaction, are replaced by an optimized subset of frequently occurring octamers that are able to prime multiple reactions.