Search for magnetic monopoles produced via the Schwinger mechanism.

Electrically charged particles can be created by the decay of strong enough electric fields, a phenomenon known as the Schwinger mechanism1. By electromagnetic duality, a sufficiently strong magnetic field would similarly produce magnetic monopoles, if they exist2. Magnetic monopoles are hypothetical fundamental particles that are predicted by several theories beyond the standard model3-7 but have never been experimentally detected. Searching for the existence of magnetic monopoles via the Schwinger mechanism has not yet been attempted, but it is advantageous, owing to the possibility of calculating its rate through semi-classical techniques without perturbation theory, as well as that the production of the magnetic monopoles should be enhanced by their finite size8,9 and strong coupling to photons2,10. Here we present a search for magnetic monopole production by the Schwinger mechanism in Pb-Pb heavy ion collisions at the Large Hadron Collider, producing the strongest known magnetic fields in the current Universe11. It was conducted by the MoEDAL experiment, whose trapping detectors were exposed to 0.235 per nanobarn, or approximately 1.8 × 109, of Pb-Pb collisions with 5.02-teraelectronvolt center-of-mass energy per collision in November 2018. A superconducting quantum interference device (SQUID) magnetometer scanned the trapping detectors of MoEDAL for the presence of magnetic charge, which would induce a persistent current in the SQUID. Magnetic monopoles with integer Dirac charges of 1, 2 and 3 and masses up to 75 gigaelectronvolts per speed of light squared were excluded by the analysis at the 95% confidence level. This provides a lower mass limit for finite-size magnetic monopoles from a collider search and greatly extends previous mass bounds.

First Search for Dyons with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions.

The MoEDAL trapping detector consists of approximately 800 kg of aluminum volumes. It was exposed during run 2 of the LHC program to 6.46 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point. Evidence for dyons (particles with electric and magnetic charge) captured in the trapping detector was sought by passing the aluminum volumes comprising the detector through a superconducting quantum interference device (SQUID) magnetometer. The presence of a trapped dyon would be signaled by a persistent current induced in the SQUID magnetometer. On the basis of a Drell-Yan production model, we exclude dyons with a magnetic charge ranging up to five Dirac charges (5g_{D}) and an electric charge up to 200 times the fundamental electric charge for mass limits in the range 870-3120 GeV and also monopoles with magnetic charge up to and including 5g_{D} with mass limits in the range 870-2040 GeV.

Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production.

MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC.

MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

Accuracy of in vivo carotid B-mode ultrasound compared with pathological analysis: intima-media thickening, lumen diameter, and cross-sectional area.

BACKGROUND AND PURPOSE: This study aimed to determine the correlation of in vivo ultrasound measurements of intima-media thickening (IMT), lumen diameter, and cross-sectional area of the common carotid artery (CCA) with corresponding measurements obtained by gross pathology and histology. METHODS: Sixty-six moribund neurological patients (mean age 71 years) underwent B-mode ultrasound of the CCA a few days before death. During autopsy, carotid specimens were removed in toto. Carotid arteries were ligated and cannulated for injection of a hydrophilic embedding material under standardized conditions. The carotid bifurcation was frozen and cut manually in 3-mm cross slices. Digital image analysis was carried out to determine the diameter and the cross-sectional area of the frozen slices of the CCA. IMT was assessed by light microscope. Ultrasonic and planimetric data were compared. RESULTS: Mean measurements of lumen diameter and cross-sectional area were 7.13+/-1.27 mm and 0.496+/-0.167 cm(2), respectively, by ultrasound, and 7.81+/-1.45 mm and 0.516+/-0.194 cm(2), respectively, by planimetric analysis of the unfixed redistended carotid arteries (R(2)=0.389 and 0.497). The mean IMT was 1.005+/-0.267 mm by ultrasound and 0.67+/-0.141 mm histologically, resulting in a mean difference of -31%. CONCLUSIONS: Transcutaneous B-mode ultrasound provides a reliable approach for in vivo measurements of the cross-sectional area and, less exactly, of the lumen diameter of the CCA. Compared with histological results, in vivo ultrasound measurements of the IMT are systematically larger.

Bronchial cholinergic tone and sensitivity in normal and asthmatic subjects.

In nine patients with asthma and 11 normal subjects, by means of specific airway conductance (Gaw/VL) and flow volume loops, we measured: resting airway caliber, bronchodilation after 0.75 and 1.50 mg of quantitatively inhaled atropine (A0.75 and A1.50), provocation dose-40 of acetylcholine (ACH) (PD40-ACH), dose ratio of ACH (DR-ACH) after saline solution, A0.75 and A1.50, and the slope of log-dose response curves to ACH (SLDRC-ACH). Normal and asthmatic subjects showed different PD40-ACH (1.26 +/- 1.37 mg and 0.34 +/- 0.32 mg) but similar resting Gaw/VL, delta Gaw/VL after A0.75 or A1.50, DR-ACH after A0.75, and SLDRC-ACH. There was no correlation between atropine-induced bronchodilatation PD40-ACH or any of the above-mentioned tests. We conclude that in normal subjects and in those with asthma, extramuscarinic or postmuscarinic receptor mechanisms may account for the presence of comparable atropine-induced bronchodilatation and resting Gaw/VL in spite of widely different PD40-ACH. The regulatory site responsible for PD40-ACH, the only test separating asthmatics from normal subjects, seemingly is located downstream from the regulatory site of other nondiscriminative tests.

Pharmacodynamic aspects of chlorpheniramine-induced bronchodilatation.

In 12 asthmatic (A) and ten normal (N) subjects, we measured the effect of inhaled saline solution, acetylcholine, histamine (H), and chlorpheniramine (CP) on specific airway conductance and forced exploratory flows. We found that CP dilated the bronchi in six asthmatic patients and one normal subject by acting on bronchial H1 receptor. This action is also modulated by the abnormal functions of this receptor-transducer, explaining why CO exerts a tonic effect only in subjects with H hyperresponsiveness. Furthermore, as shown by CO and CP + H responses, bronchial histamine seems to be present primarily in large airways and in relatively small amounts. We also found that bronchial H, the abnormal H1 receptor-transducer, and the bronchial caliber are regulated independently of each other. Consequently, this limits the therapy with H1 blockers in asthma.

Airway obstruction in adults with recurrent respiratory infections and IgG deficiency.

In 42 adults with recurrent respiratory infections (RRI) and common variable immunodeficiency or immunoglobulin G (IgG) subclass deficiency, the results of pulmonary function tests were related to factors apt to produce airway obstruction: serum concentration of IgG and IgG subclasses, various features of acute RRI (number/year, time from onset to diagnosis, episodes of pneumonia, etc) and type of chronic lung disease (smoking and nonsmoking related chronic bronchitis, episodic wheezing, and bronchiectasis). Compared with nonsmokers, usually less than 40 years of age, the patients above 40 had smoking-related chronic bronchitis and had obstruction (%FEV1/forced vital capacity [FVC] 55.3 +/- 8.1 vs 80.1 +/- 4.5), hyperinflation (residual volume 182.7 +/- 22.7 percent vs 109.7 +/- 8.8 percent of pred) hypoxemia (66.6 +/- 5.8 vs 83.4 +/- 4.2 mm Hg) and impaired carbon monoxide transfer (65.5 +/- 9.1 percent vs 93.3 +/- 5.8 percent). The features of acute or chronic RRI, the time from onset to diagnosis (< 10 yr in the entire group), the type of IgG deficiency or the serum concentration of the deficient protein did not correlate with substantial obstruction (FEV1/FVC < 70%). In conclusion, in adults with IgG deficiency and RRI for less than 10 yr, smokers with chronic bronchitis rather than nonsmokers develop substantial airway obstruction.

Provocation dose and discriminant analysis in histamine bronchoprovocation. Are the current predictive data satisfactory?

In 20 normal subjects (N) and 20 asthmatic patients (A) using bronchodilators as needed, the PD40, PD10, PD15, PD20, PD10T, and PD20C were measured (PD being provocation dose, subscript being -% delta in Gaw/VL for PD40, lowest FEV1 for PD20C, and best FEV1 for the remaining PDs; 10T means delta FEV1 greater than -10 percent). For discriminant analysis we used an ad hoc graphic (best case) method, a ceiling method based on highest PD in A and two methods (logistic and linear) which considered PDs in both N and A (PDN and PDA, respectively). The distribution of PDN and PDA had substantial overlap and appeared log normal. The PD15, PD20, and PD20C displayed the smallest mean misclassification error followed by PD10T, PD40, and PD10. The linear and logistic methods produced balanced sensitivity and specificity but, predictably, a misclassification error higher than that of the graphic method. The ceiling method proved unsatisfactory with 100 percent sensitivity but approximately equal to 60 percent specificity. Using linear and logistic methods, the posttest likelihood of asthma could be expressed as a function of its pretest likelihood and level of PD recorded. We concluded that: (1) the most discriminant PDs are PD20, PD15 and PD20c; and (2) new normative data for diagnostic bronchoprovocation are needed, because: (a) when PDA and PDN overlap, the currently used ceiling method leads to a high misclassification rate, while the linear and logistic method based on mathematical model have a better discriminant ability; (b) to separate PDA from PDN and allow the application of the ceiling method, "as-needed bronchodilators" is not a reproducible criterion.

Effect of an H1 blocker, chlorpheniramine, on inhalation tests with histamine and allergen in allergic asthma.

In 15 asthmatic subjects, flow volume loops were recorded before and after quantitative nebulization of increasing concentration of histamine and allergen, until a threshold response (-delta FEV1 > 10%) was obtained. Nine subjects with reproducible threshold doses to these two agents were included in the study. After pretreatment with 10 mg of intravenously administered chlorpheniramine, the threshold dose of histamine increased fourfold in eight subjects and eightfold in one subject, whereas the threshold doses to allergen doubled in seven and remained unaffected in two. One of these two subjects required 15 mg chlorpheniramine intravenously for comparable protection. In three subjects, the threshold dose to inhaled acetylcholine was determined with a similar procedure and found reproducible. Pretreatment with 10 to 15 mg chlorpheniramine increased this threshold dose two to four times, similarly to the effect produced by 0.4 mg of subcutaneously administered atropine. However, 0.4 mg atropine sc. did not alter the airway responses to allergen. The results suggest that intravenously administered chlorpheniramine provided it has a dose ratio of at least four against inhaled histamine, can prevent attacks of allergen-induced asthma. The effect is probably mediated through the H1 rather than the acetylcholine receptor.

Dose-related dilatation of airways after inhalation of metaproterenol sulfate.

Studies concerning the ability of an inhaled beta2-agonist to produce dose-related bronchodilatation are conflicting. In five asthmatic, five bronchitic, and five normal subjects, specific airway conductance (Gaw/VL), flow-volume curves, and single-breath nitrogen washout were recorded after noncummulative inhalation of 0.65 mg, 1.30 mg, 1.95 mg, and, in some subjects, 2.60 mg of metaproterenol sulfate. Bronchodilatation appeared to be dose-related and was best assessed by using Gaw/VL; in all but one subject with chronic bronchitis, there was a significant linear relationship between log dose and precent change in Gaw/VL. Measurements of flow rate could demonstrate significant log dose-responses in eight subjects, maximum midexpiratory flow being the most sensitive measurement of flow rate, followed in order by forced expiratory volume in one second, flow at 50 percent of forced vital capacity, peak expiratory flow rate, and flow at 75 percent of forced vital capacity. No log dose-respone curve could be observed by using the single-breath nitrogen-washout technique. This demonstration of significant log dose-responses to inhaled metaproterenol is consistent with the response to drugs acting upon receptors and suggests that patients may benefit from increasing doses of bronchodilators.

The relationship between conductance and functional residual capacity during drug-induced bronchoconstriction.

UNLABELLED: We wondered if the inverse changes in airway conductance (Gaw) and functional residual capacity (FRC) during histamine (H) and acetylcholine (ACH) challenge are interrelated or occur at random. In 14 normal and 14 asthmatic subjects, we determined FRC and Gaw changes corresponding to changes in specific airway conductance (SGaw) around -40 percent produced by an aerosol of H or ACH inhaled quantitatively and with measured lung deposition. We also assessed the elastic recoil following H inhalation (5A). We found that in 11 normal and nine asthmatic subjects, after H or nine normal and 11 asthmatic subjects after ACH, Gaw and 1/FRC were linearly and directly related (p less than 0.05). The steepness of this slope was directly related to the resting Gaw values. A similar relation was uncovered in the literature for asthmatic patients at rest or during recovery from natural asthma. As the elastic recoil was normal and did not change after H, it could not explain delta FRC at delta SGaw of -40 percent. IN CONCLUSION: (1) during H or ACH challenge, Gaw-FRC relationship in normal or asthmatic subjects tends to be hyperbolic and dependent on resting Gaw; (2) such a relationship is seemingly present in other bronchoconstrictor responses with a different pathogenesis; and (3) during bronchoconstriction, as Gaw vs FRC is no longer linear, SGaw becomes volume dependent.

Respiratory pharmacology. Beta-adrenergic drugs.

This article reviews the enormous literature on beta agonists, emphasizing three aspects: the structural, pharmacokinetic, pharmacodynamic, and toxicologic properties that are essential for understanding the clinical application of these drugs; the relative advantages and disadvantages of various routes of administration, including the different ways of prescribing the aerosols; and the pharmacologic factors that may limit the further development of these compounds for therapy.

The classic antihistamines (H1 blockers) in respiratory medicine.

For almost a quarter of a century, the pharmacology of H1 blockers remained quasi-stagnant, isolated from the rapid evolution of clinical pharmacology. However, exciting new developments concerning the role of histamine in asthma, and special pharmacodynamic features of new H1 blockers, have revived our interest in these drugs.

A study of the radiobiological effectiveness with track etch detectors.

CR-39 nuclear track detectors have been used in this experiment to study the killing effect of low energy protons on V79-753B Chinese hamster cells and to monitor the proton beam. The estimated surviving fractions and the beam parameters are comparable to those found with conventional electronic devices. The surviving fractions fitted by the linear quadratic model support the idea of single-hit mechanism for the cell killing.

[Thoracic sympathectomy via the thoracoscopic approach. The operative technic]. / Simpatectomia toracica pe cale toracoscopica. Tehnica operatorie.

The authors describe the technique of thoracic sympathectomy by thoracoscopic approach in the variant in which the sympathetic chain is divided between T4 and T5 sympathetic ganglion associated with the division of the gray and white rami communicantes of the T2-T3-T4 sympathetic ganglions. The article emphasizes the importance of the 2nd sympathetic ganglion in the regulation of the blood circulation of the arm and the advantages of the thoracoscopic approach for this type of intervention.

[Specific features of the clinical course and treatment of chronic tonsillitis in children]. / Osobennosti klinicheskogo techeniia i lecheniia khronicheskogo tonzillita u detei.

This author applied present-day methods--clinical, immunological, immunomorphological--to examine 2262 children with chronic tonsillitis and processed the data obtained statistically. The emergence and development of chronic tonsillitis were strongly stimulated by preceding cases of angina, acute respiratory pathologies, flu, and other infectious diseases. The children were treated using dioxidine, desensitizing drugs, vitamins, ultrasonic and tubus-quartz exposures as well as levamisole. The treatment was effective and caused no complications.