Free-electron laser design for four-wave mixing experiments with soft-x-ray pulses.

We present the design of a single-pass free-electron laser amplifier suitable for enabling four-wave mixing x-ray spectroscopic investigations. The production of longitudinally coherent, single-spike pulses of light from a single electron beam in this scenario relies on a process of selective amplification where a strong undulator taper compensates for a large energy chirp only for a short region of the electron beam. This proposed scheme offers improved flexibility of operation and allows for independent control of the color, timing, and angle of incidence of the individual pulses of light at an end user station. Detailed numerical simulations are used to illustrate the more impressive characteristics of this scheme.

Sex differences in functional outcome after hospitalisation: A systematic review and meta-analysis.

The aims of this review were to determine: i) how many studies have examined global functioning outcomes from a psychiatric inpatient stay disaggregated by sex; and ii) if women have worse global functioning outcomes than men following an admission. A systematic review following PRISMA guidance and meta-analysis were conducted. Thirty-six studies met eligibility criteria for inclusion in the review. Of these, eleven papers provided sufficient data to conduct a meta-analysis of global functioning outcomes comparing men and women. Overall, differences between men and women were small. The meta-analysis revealed either no difference or a small significant difference in global functioning outcomes in favour of women, contrary to expectations. As many as 93% of otherwise eligible studies had to be excluded for not disaggregating data by sex. Women may have slightly superior functioning outcomes than men suggesting that inpatient services should be more heavily focused on applying principles of gender-informed care for men as well as women. The finding that so many potential studies had to be excluded for not reporting sex differences is consistent with other mental health literature and highlights a need for better reporting practices in relation to sex differences.

Twin-pulse seeding enables pump-probe capabilities in the EUV to soft X-ray spectrum at synchrotron light sources.

Having previously reported that separating the two stages of echo-enabled harmonic generation (EEHG) with one or more bending magnet (BM) sections allows the BMs to serve as the desired source of momentum compaction, here we demonstrate that this arrangement can greatly reduce the total energy modulation required by any 4th generation synchrotron light source, leading to higher repetition rates as well as stronger coherent radiation output power, with significant benefits. Since the EEHG beamline performance is mainly determined by the momentum compaction, beam emittances and beta functions of a storage ring lattice, allowing for different separations between the two stages is a straightforward way to increase the momentum compaction of chicane 1. This also enables pump-probe capabilities in a novel context, where twin-pulse seeding on the same electron bunch would allow two distinct radiation pulses with an adjustable delay in the range of 0.1 to 10 ps. In the twin-pulse seeding scheme, the same electron bunch could undergo modulation from two distinct laser pulses. Later stages would produce independent harmonics in subsequent straight sections. There are two variations of this twin-pulse seeding scheme, supporting different scientific applications. With a common modulation in stage 1, the first option allows simultaneously two independent radiation sources, with a full coverage of the EUV (2.5 to 50 nm) to soft X-ray (1.25 to 2.5 nm) spectrum; for the second option, the same stage 2 undulator could generate two coherent pulses both fitting within the FEL bandwidth, or at distinct harmonics. We present particle tracking simulation studies based on the APS-U lattice, including quantum excitation and radiation damping. These simulations indicate that there is no degradation of the modulated longitudinal phase space even when the two stages are separated by as many as 10 BM sections.

Optimization of echo-enabled harmonic generation toward coherent EUV and soft X-ray free-electron laser at NSLS-II.

Prebunching via echo-enabled harmonic generation (EEHG) is an efficient way to reduce the radiator length and improve the longitudinal coherence as well as output stability in storage-ring-based free-electron lasers. We propose a conceptual design, which uses two straight sections to seed coherent extreme-ultraviolet (EUV) and soft X-ray emission with nearly MHz repetition rate. To take the large energy spread (10-3) of a storage ring into account and utilize the existing bending magnets between the two straight sections as the first chicane, we implement a special modeling tool, named EEHG optimizer. This tool has been successfully applied to maximize the prebunching with a reasonably low energy modulation, thereby generating intense coherent X-ray pulses within a short undulator length (a few meters) limited by the available space of a storage ring. Numerical simulations confirm that the optimized EEHG parameters can be directly applied to generate a 10 MW scale peak power with fully coherent ultrafast EUV to soft X-ray pulses based on the NSLS-II parameters. This method can be easily extended to other types of diffraction-limited storage rings.

Toward fully coherent soft x-ray free-electron laser via echo-enabled harmonic generation in fourth generation synchrotron light sources.

Having previously reported on bunching via echo-enabled harmonic generation (EEHG) as an effective way to improve the longitudinal coherence in the NSLS-II storage ring [X. Yang et al., Sci. Rep. 12, 9437 (2022)], we demonstrate that this EEHG scheme can be easily adopted to any fourth generation diffraction-limited synchrotron light source with significant benefits. The advantage of the scheme is that it requires no change of the lattice and is fully compatible with other beamlines. Since the EEHG performance is mainly determined by the momentum compaction, beam emittances, and beta functions of a SR lattice, we have identified these crucial parameters and successfully built a generalized model, which can predict the performance of nearly any SLS. Regarding the fourth generation SLSs, momentum compactions are often significantly smaller; thus, to cover the x rays with a photon energy of up to 1 keV, we utilize a specific design, including a 250 nm seed-laser wavelength. Our model predicts that for most of the current and future fourth generation SLSs, the EEHG scheme can produce significant prebunching up to harmonic 200 and, thus, generate a few MW scale peak power at 1.25 nm wavelength.

Genetic variants of G4 globulin. A unique relationship to other classes of G globulin.

Two types of gammaG4 proteins, termed 4a and 4b, were characterized through antigenic studies of myeloma proteins. Both were recognized by specific antigens on the Fc fragment which were shared with other gammaG classes. The distinctive antigen of the common 4a type was shared with all gammaG1 and gammaG3 proteins but missing in those of the gammaG2 class; that for the rarer 4b type was selectively found in proteins of the gammaG2 class. Analyses on gammaG4 fractions isolated from normal sera showed that either the 4a or the 4b or a mixture of the two types was present in each serum. Evidence was obtained that these differences were on a genetic basis and that allelic genes linked to those of the Gm system were involved. Such a reciprocal occurrence in other classes of gammaG globulin of the antigenic markers distinguishing genetic variants has not been observed previously. A number of questions regarding the evolutionary development of the genes responsible are discussed. The possibility is raised that those for the gammaG4 class arose relatively early and preceded the development of those for the other gammaG classes.

Phosphonoformate and phosphonoacetate derivatives of 5-substituted 2'-deoxyuridines: synthesis and antiviral activity.

The synthesis of potential "combined prodrugs" wherein phosphonoformate or phosphonoacetate was attached to the 5'-position of 2'-deoxyuridine, 2'-deoxythymidine, 5-iodo-2'-deoxyuridine (IDU), 5-(2-chloroethyl)-2'-deoxyuridine (CEDU), or 5-(2-bromovinyl)-2'-deoxyuridine (BVDU) or to the 3'-position of CEDU is described. The antiviral activities of these derivatives and of reference compounds were compared in Vero, HEp-2, and primary rabbit kidney cells against herpes simplex virus types 1 and 2 (HSV-1 and -2). The CEDU and BVDU analogues were also evaluated against systemic and intracutaneous HSV-1 infection in mice. The nature of the 5-substituent proved critical for antiviral activity, since only the 5-iodo-, 5-(2-bromovinyl)-, and 5-(2-chloroethyl)-substituted derivatives were inhibitory to the herpesviruses. Furthermore, the type specificity is determined by the nature of the 5-substituent: the IDU analogues were similarly inhibitory to HSV-1 and -2 whereas the CEDU and BVDU analogues inhibited HSV-2 replication only at considerably higher concentrations than HSV-1. In vivo, several derivatives were shown to possess significant antiviral activity; however, none surpassed its respective parent compound, CEDU or BVDU, in potency. It seems improbable, therefore, that a synergistic effect between PFA or PAA and the nucleoside analogue occurred. The extent of in vitro and in vivo activity of the CEDU and BVDU 5'-phosphonoformates and 5'-phosphonoacetates is most plausibly explained by the ease by which the "combined prodrugs" are hydrolyzed and the parent compound, CEDU and BVDU, respectively, is released.

Nd:YAG laser and photodynamic therapy for esophageal and endobronchial tumors under general and local anesthesia. Effects on arterial blood gas levels.

STUDY OBJECTIVE: Our objective was to determine the respiratory and acid-base metabolism response to endoscopic laser surgery for obstructive tumors, as related to the duration and different types of endoscopy, anesthesia, and laser treatment. DESIGN: The design was a case-control, cohort analytic, nonrandomized controlled survey of case series before and after endoscopic procedures. SETTING: A referral-based surgery and oncology practice at one hospital's laser center. PATIENTS: We studied a sequential sample of 82 patients in the age range from 35 to 92 years, with malignant and benign, primary and metastatic, partially and completely obstructing esophageal (15 patients) and endobronchial (67 patients) tumors. INTERVENTIONS: A total of 229 diagnostic, laser treatment, and follow-up endoscopic procedures was performed under general or local anesthesia (46 esophagoscopies and 183 bronchoscopies). The latter group consisted of 29 cases of general and 154 cases of local topical anesthesia. The last group involved 37 diagnostic and toilet bronchoscopies, 86 cases of YAG-laser tumor ablation, and 31 cases of PDT. MEASUREMENTS AND MAIN RESULTS: Direct-reading electrode measurements of arterial blood, sampled before and immediately after the endoscopic procedure, revealed statistically significant (p less than 0.001) increases in PaCO2 (200 of 229 cases) and decreases in pH (195 of 229 cases) and PaO2 (215 of 229 cases). These findings were similar after bronchoscopy and esophagoscopy, general and local anesthesia (only the decrease in pH was less pronounced in the latter case), and explorative endoscopies and different laser treatments and did not correlate with the total duration of the procedure within the wide time range of 7 to 210 minutes. The initial preoperative level of PaCO2 was considerably higher and the level of PaO2 was significantly lower in patients with endobronchial tumors, as compared to patients with esophageal cancer. A strong, inverse linear relationship was found between the perioperative changes in PaO2 and its initial level and between PaCO2 and pH changes. CONCLUSIONS: The PDT for esophageal and endobronchial malignancies is no more harmful for acid-base metabolism and respiratory functions than YAG-laser tumor ablation or any other common, nonlaser endoscopic procedure.

Beam envelope equations for cooling of muons in solenoid fields

Muon cooling is a critical component of the proposed muon collider and neutrino factory. Previous studies of cooling channels have tracked single muons through the channel, which requires many particles for good statistics and does not lend itself to an understanding of channel dynamics. In this paper, a system of moment equations are derived which captures the major aspects of cooling: interactions with material and acceleration by radio frequency (rf) cavities. A general analysis of solenoid lattice types compares well with prior simulations and indicates new directions for study.

Selective IgA deviciency in Charcot-Marie-Tooth disease.

A selective IgA deficiency was found in five of 15 random patients with Charcot-Marie-Tooth disease. Immunologic studies of 32 members of the five families showed low IgA in 17 of the members, associated with elevated IgM in 20, without other significant immune abnormalities. The immunoglobulin pattern and the variability of symptoms in this familial peripheral neuropathy suggest that a thymic or gut-associated immune deficiency or both, may be causally related to the disease process.

Thymic changes in histiocytosis.

In order to arrive at a hypothesis of the pathogenesis of thymic changes in histiocytosis, the thymus glands from thirty-two children with histiocytosis were studied. In general, the changes were a severe loss of cortical and medullary structures rather than stress type changes in which only the cortical structure changes. The thymic changes were then classified into three main groups: severe dysplasia equivalent to that seen in congenital immune deficiency, severe nonspecific involution, and a third group designated as a dysmorphic type which resembled those with dysplasia, but, in addition, showed smaller lobules and interstitial histiocytic infiltration. The thymic changes correlated with the type of histiocytic disease. For the purposes of this study, the disease was categorized as Type I or Type II, as previously described. Dysplastic changes were only seen in those patients with Type I histiocytic disease, while involution occurred in patients with Type II histiocytic disease. Dysmorphic change was apparent in both, but it had a much higher incidence in Type II.

Persistent falsely positive rapid tests for infectious mononucleosis. Report of five cases with four--six-year follow-up data.

In many laboratories, rapid slide tests incorporating differential absorption have replaced heterophil antibody tube tests in the investigation of suspect infectious mononucleosis. The present report describes serologic data from five individuals whose Monospot tests remained falsely positive for four years or more without other evidence of infectious mononucleosis or underlying disease states. Three of the five had never been infected with the Epstein-Barr virus. All five had negative results when studied with the ox cell hemolysin and the horse cell differential absorption tube tests. False-positive test results have also been encountered in healthy controls, as frequently as in patients with underlying disease states. The authors are unable to attach any clinical significance to the findings of an isolated falsely positive Monospot test even when it persists for many months or years.

Factors associated with continued smoking during pregnancy: analysis of socio-demographic, pregnancy and smoking-related factors.

This study investigated the characteristics associated with smoking during pregnancy. A total of 7836 pregnant women were surveyed between 1992 and 1999 in England. Of these 27% were smoking during pregnancy. Pregnant women were more likely to smoke if they were less educated, living in rented accommodation, in unskilled manual or unemployed groups, and single or had a partner who smokes. Analysed by logistic regression, whether or not a pregnant women has a partner and, if so, his smoking status, was by far the biggest predictor of the pregnant woman's current smoking status. Thus, compared with women with partners who never smoke, the odds ratio (OR) of smoking during pregnancy for women with a partner who smokes was 2.3 (1.9-2.7) while those with no partner had an OR of 4.8 (3.8-6.0). For women exposed to passive smoke at home or at work the OR was 2.5 (2.1-3.0). Housing tenure was the most important socio-demographic predictor. Thus pregnant women living in rented council housing were nearly twice as likely (OR 1.93;1.63-2.29) as those buying their own home to be current smokers. The number of women who continued to smoke during pregnancy increased 10-fold from the least to the most deprived group. These findings highlight the importance of tobacco control strategies that address pregnant women's life circumstances and broader inequalities as well as those that focus on individual smoking behaviour.