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J Maser

Publications and source records attributed to J Maser.

16 recordsLinked to original sources
PubMed2006

Nanometer linear focusing of hard x rays by a multilayer Laue lens.

We report on a type of linear zone plate for nanometer-scale focusing of hard x rays, a multilayer Laue lens (MLL), produced by sectioning a multilayer and illuminating it in Laue diffraction geometry. Because of its large optical depth, a MLL spans the diffraction regimes applicable to a thin Fresnel zone plate and a crystal. Coupled wave theory calculations indicate that focusing to 5 nm or smaller with high efficiency should be possible. Partial MLL structures with outermost zone widths as small as 10 nm have been fabricated and tested with 19.5 keV synchrotron radiation. Focal sizes as small as 30 nm with efficiencies up to 44% are measured.

Journal Article↗
PubMed2000

Illumination for coherent soft X-ray applications: the new X1A beamline at the NSLS.

The X1A soft X-ray undulator beamline at the NSLS has been rebuilt to serve two microscopy stations operating simultaneously. Separate spherical-grating monochromators provide the resolving power required for XANES spectroscopy at the C, N and O absorption edges. The exit slits are fixed and define the coherent source for the experiments. The optical design and the operational performance are described.

Journal Article↗
PubMed2000

Soft X-ray microscopy with a cryo scanning transmission X-ray microscope: II. Tomography.

Using a cryo scanning transmission X-ray microscope (Maser, et al. (2000) Soft X-ray microscopy with a cryo scanning transmission X-ray microscope: I. Instrumentation, imaging and spectroscopy. J. Microsc. 197, 68-79), we have obtained tomographic data-sets of frozen hydrated mouse 3T3 fibroblasts. The ice thickess was several micrometres throughout the reconstruction volume, precluding cryo electron tomography. Projections were acquired within the depth of focus of the focusing optics, and the three-dimensional reconstruction was obtained using an algebraic reconstruction technique. In this first demonstration, 100 nm lateral and 250 nm longitudinal resolution was obtained in images of unlabelled cells, with potential for substantial further gains in resolution. Future efforts towards tomography of spectroscopically highlighted subcellular components in whole cells are discussed.

3T3 Cells↗
PubMed2000

Soft X-ray microscopy with a cryo scanning transmission X-ray microscope: I. Instrumentation, imaging and spectroscopy.

We have developed a cryo scanning transmission X-ray microscope which uses soft X-rays from the National Synchrotron Light Source. The system is capable of imaging frozen hydrated specimens with a thickness of up to 10 microm at temperatures of around 100 K. We show images and spectra from frozen hydrated eukaryotic cells, and a demonstration that biological specimens do not suffer mass loss or morphological changes at radiation doses up to about 1010 Gray. This makes possible studies where multiple images of the same specimen area are needed, such as tomography (Wang et al. (2000) Soft X-ray microscopy with a cryo scanning transmission X-ray microscope: II. Tomography. J. Microsc. 197, 80-93) or spectroscopic analysis.

3T3 Cells↗
PubMed1999

The bipolar spectrum: a clinical reality in search of diagnostic criteria and an assessment methodology.

Failure to recognize subthreshold expressions of mania contributes to the frequent under-diagnosis of bipolar disorder. There are several reasons for the lower rate of recognition of subthreshold manic symptoms, when compared to the analogous pure depressive ones. These include the lack of subjective suffering, enhanced productivity, ego-syntonicity, and diurnal and seasonal rhythmicity associated with many of the manic and hypomanic symptoms, and the psychiatrists' tendency to subsume persistent or even alternating symptoms among personality disorders. Furthermore, the central diagnostic importance placed on alterations in mood distracts clinicians from paying attention to other more subtle but clinically meaningful symptoms, such as changes in energy, neurovegetative symptoms and distorted cognitions. Although officially accepted in both ICD-10 and DSM-IV, we believe bipolar II disorder is underdiagnosed because of inattention to symptoms of hypomania. Moreover, by requiring the presence of both full-blown hypomanic and major depressive episodes, current nosology fails to include symptoms or signs which are mild and do not meet threshold criteria. There is already agreement in the field that such symptoms are important for depression. We now propose that attention should also be devoted to mild symptomatic manifestations of a manic diathesis, even if such manifestations may sometimes enhance quality of life. The term 'spectrum' is used to refer to the broad range of such manifestations of a disorder from core symptoms to temperamental traits. Spectrum manifestations may be present during, between, or even in the absence of, an episode of full-blown disorder. We have developed a structured clinical interview to assess the mood spectrum (SCI-MOODS) to evaluate the whole range of depressive and manic symptoms. This instrument is currently undergoing psychometric testing procedures. Similar to the SCID interview, the SCI-MOODS interview provides a separate rating for each of the major DSM-IV symptoms, but the latter also identifies and rates subthreshold and atypical manifestations. This paper presents the concept of a subthreshold bipolar disorder and discusses the potential epidemiological, diagnostic and therapeutic relevance of such a spectrum conditions. We also describe the SCI-MOODS interview used reliably to identify the occurrence of a bipolar spectrum condition. Obviously a great deal of systematic research needs to be conducted to ascertain the reliability and validity of subthreshold bipolarity as summarized in this paper and embodied in our instrument.

Bipolar Disorder↗
PubMed1998

Alcoholism and drug abuse in three groups--bipolar I, unipolars and their acquaintances.

OBJECTIVE: Previous work has shown that manic-depressive illness and alcohol abuse are linked. This study further explores the relationship of alcohol and drug abuse in bipolar I patients and unipolar depressives and a comparison group obtained through the acquaintance method. METHOD: Diagnosis was accomplished according to Research Diagnostic Criteria (RDC): controls = 469; bipolars = 277; unipolar depressives = 678. Systematic data were gathered using the SADS on lifetime and current drug abuse and alcoholism. Both patients and comparison subjects were then followed prospectively for 10 years. First degree family members were interviewed using the RDC family history method. RESULTS: The group of bipolar patients and the group of unipolar patients had higher rates of drug and alcohol abuse than the comparison group when primary and secondary affective disorder patients were combined. However, primary unipolar patients did not have higher rates of alcohol or drug abuse than the comparison group. In contrast, primary bipolar patients had higher rates of alcoholism, stimulant abuse, and ever having abused a drug than the primary unipolar group and the control group. In an evaluation of the bipolar patients, drug abusers were significantly younger at intake and had a significantly younger age of onset of bipolar disorder. There was a significant increase in family history of mania or schizoaffective mania in the drug-abusing bipolar patients as compared to the non-abusing bipolar patients. LIMITATION: As in all adult samples of patients with affective illness, the chronology of alcohol and substance problems vis-à-vis the onset of illness was determined retrospectively. CONCLUSIONS: (1) Alcoholism and drug abuse are more frequent in bipolar than unipolar patients. (2) The drug abuse of bipolar patients tends toward the abuse of stimulant drugs. (3) In a bipolar patient, familial diathesis for mania is significantly associated with the abuse of alcohol and drugs. (4) More provocatively, these findings suggest the hypothesis of a common familial-genetic diathesis for a subtype of bipolar I, alcohol and stimulant abuse. CLINICAL IMPLICATIONS: The present analyses, coupled with two previous ones from the CDS, suggest that drug abuse may precipitate an earlier onset of bipolar I disorder in those who already have a familial predisposition for mania. Furthermore, in dually diagnosed patients with manic-depressive and alcohol/stimulant abuse history, mood stabilization of the bipolar disorder represents a rational approach to control concurrent alcohol and drug problems, and should be studied in systematic controlled trials.

Adult↗
PubMed1996

Stable trait components of hopelessness: baseline and sensitivity to depression.

Hopelessness (H) plays an important theoretical and practical role in depression. The authors hypothesized that a patient's H is comprised of (a) a baseline level of H when not depressed and (b) an increment in H related to the severity of depression at the time and the person's rate of increase in H as a function of severity of depression (sensitivity). Baseline and sensitivity are explanatory stable traits; H and depression are observed, time-varying states. The corresponding statistical model described well the longitudinal data of 316 participants. Baseline and sensitivity were uncorrelated and correlated with different clinical and demographic variables. Baseline predicted a future suicide attempt; sensitivity and H when depressed did not. It may be useful to ask "How hopeless is this person when not depressed and how much more hopeless is he or she when depressed?", rather than simply "How hopeless is this depressed person?"

Adolescent↗
PubMed1996

X-ray microscopy: preparations for studies of frozen hydrated specimens.

X-ray microscopes provide higher resolution than visible light microscopes. Wet, biological materials with a water thickness of up to about 10 microns can be imaged with good contrast using soft X-rays with wavelengths between the oxygen and carbon absorption edges (at 24 and 43 A). The Stony Brook group has developed and operates a scanning transmission X-ray microscope (STXM) at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The microscope is used for imaging with a current resolution of 50 nm, and for elemental and chemical state mapping. Radiation damage imposes a significant limitation upon high resolution X-ray microscopy of room temperature wet specimens. Experience from electron microscopy suggests that cryo techniques allow vitrified specimens to be imaged repeatedly. This is due to the increased radiation stability of biological specimens in the frozen hydrated state. Better radiation stability has been shown recently with a cryo transmission X-ray microscope developed by the University of Göttingen, operating at the BESSY storage ring in Berlin, Germany. At Stony Brook, we are developing a cryo scanning transmission X-ray microscope (CryoSTXM) to carry out imaging and spectro-microscopy experiments on frozen hydrated specimens. This article will give an outlook onto the research projects that we plan to perform using the CryoSTXM.

Animals↗
PubMed1993

The enduring psychosocial consequences of mania and depression.

OBJECTIVE: The authors sought to determine the scope, severity, and persistence of psychosocial impairment arising from bipolar and unipolar affective disorder. METHOD: Patients with bipolar (N = 148) or unipolar (N = 240) major affective disorder were assessed as they sought treatment and again after a 5-year follow-up. Concurrently, parents, siblings, and adult children underwent similar assessments and were followed for 6 years. To quantify the impact of affective disorder, probands were individually matched to relatives who had no lifetime history of affective disorder. Sixty-nine relatives who were depressed at intake constituted a separate, nonclinical study group and were also matched to relatives who were well. RESULTS: Both unipolar and bipolar patients began follow-up with deficits in annual income. Relative to comparison subjects, affective disorder groups were significantly more likely to report declines in job status and income at the end of follow-up and significantly less likely to report improvements. Similarly, both bipolar and unipolar patients showed significant deficits in nearly all other areas of psychosocial functioning measured at follow-up. Except for relationships with spouses, deficits did not differ significantly by polarity. Surprisingly, probands with recovery sustained throughout the final 2 years of follow-up also showed severe and widespread impairment. Relatives with major depression exhibited substantial deficits on follow-up, but job status and income were not significantly affected. CONCLUSIONS: The psychosocial impairment associated with mania and major depression extends to essentially all areas of functioning and persists for years, even among individuals who experience sustained resolution of clinical symptoms.

Adaptation, Psychological↗
PubMed1970

Forgetting and conditioned suppression: role of a temporal discrimination.

Several experiments have found complete retention of conditioned suppression when overall suppression to the signal for shock was measured. The present experiment examined retention of conditioned suppression but did so with a paradigm that produced temporal discrimination of shock occurrence. Nine rats were exposed to a flashing light signal of 5-min duration that always terminated with a shock. After several months, a temporal discrimination was well established, as shown by maximum suppression toward the end of the signal period. After remaining in the home cage for 25 days, the rats were again subjected to the conditioning procedure. The overall level of suppression remained the same but the temporal discrimination was not observed.

Animals↗
PubMedDate not supplied

Quality of life in rheumatoid arthritis: impact of disability and lifetime depressive spectrum symptomatology.

OBJECTIVE: The aim of this study was to investigate the impact of disability and lifetime subthreshold depressive symptoms on Health-Related Quality of Life (HRQoL) among patients with rheumatoid arthritis (RA). METHODS: Ninety-two subjects with a diagnosis of RA according to the American College of Rheumatology (ACR) criteria were recruited at the Department of Rheumatology of the University Hospital, Pisa, Italy. Participants who met DSM-IV-TR diagnostic criteria for current or previous Axis I disorders were excluded. Assessments of functional status and disability was conducted using both the ACR classification and the Stanford Health Assessment Questionnaire (HAQ). Health-related Quality of Life was assessed using the Medical Outcomes Study Short Form 36 health survey questionnaire (MOS-SF36) and lifetime depressive spectrum symptomatology using the Mood Spectrum Questionnaire, Self-Report version (MOODS-SR). RESULTS: Comparison with MOS-SF36 Italian normative values indicated that RA patients were significantly impaired on mental and physical HRQoL areas. Correlations between MOODS-SR depressive scores and ACR severity (Spearman rho = 0.15, p = 0.07) and HAQ score (Spearman rho = 0.20, p = 0.05) were modest in absolute value and borderline significant. Lifetime mood depressive spectrum was related with impaired HRQoL levels, both in physical (except for bodily pain) and mental (except for social functioning) domains. Associations of mood depressive spectrum and general health, vitality, role emotional and mental health continued to be significant after controlling for functional status, duration of illness, age and gender. CONCLUSIONS: Because lifetime mood depressive symptoms significantly contribute to impairment in HRQoL in RA patients without a past psychiatric history, even after controlling for functional status, duration of illness and demographic characteristics, these symptoms should be assessed for an accurate clinical evaluation and appropriate clinical management of RA patients.

Affect↗