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We review some of our recent work devoted to the problem of quantization with preservation of Noether symmetries, finding hidden linearity in superintegrable systems, and showing that nonlocal symmetries are in fact local. In particular, we derive the Schrödinger equation for the isochronous Calogero goldfish model using its relation to Darwin equation. We prove the linearity of a classical superintegrable system on a plane of nonconstant curvature. We find the Lie point symmetries that correspond to the nonlocal symmetries (also reinterpreted as λ-symmetries) of the Riccati chain. [ABSTRACT FROM AUTHOR]

The Jacobi last multiplier has an intimate association with the symmetries of differential equations. We present four examples in which the inability to obtain a last multiplier using the method of Lie itself provides us with information. We show that the three representations of the complete symmetry group of the linear harmonic oscillator can be obtained by searching for Jacobi last multipliers: they correspond to the Lie point symmetries that have zero determinant, thus far regarded as a useless case. The point is emphasized using the examples of the Volterra-Verhulst-Pearl equation, the Kepler problem and a scalar equation of fourth order. [ABSTRACT FROM AUTHOR]

In this work we present results on the construction of λ-symmetries for ordinary differential equation using ideas derived from the notion of nonlocal symmetries and Jacobi last multiplier. We then apply the results obtained to the case of ordinary difference equations. [ABSTRACT FROM AUTHOR]

We propose a Lie-Noether-symmetry solution of two problems that arise with classical quantization: the quantization of higher-order (more than second) Euler-Lagrange ordinary differential equations of classical mechanics and the quantization of any second-order Euler-Lagrange ordinary differential equation that classically comes from a simple linear equation via nonlinear canonical transformations. [ABSTRACT FROM AUTHOR]

The article presents guidelines for the prevention of fungal infections in hematopoietic cell transplantation (HCT) recipients. It talks about the prevention of yeast infections such as invasive candidiasis by the use of fluconazole drug before engraftment in allogeneic HCT recipients. It also talks about the prevention of mold infections, and mentions that nosocomial mold infections in HCT recipients may result from respiratory exposure to fungal spores.

It is well known that for any second-order ordinary differential equation (ODE), a Lagrangian always exists, and the key to its construction is the Jacobi last multiplier. Is it possible to find Lagrangians for first-order systems of ODEs or for higher-order ODEs? We show that the Jacobi last multiplier can also play a major role in this case. [ABSTRACT FROM AUTHOR]

The incidence of Gram-negative bacteremia has increased in hematopoietic stem cell transplant (HSCT) recipients. We prospectively collected data from 13 Brazilian HSCT centers to characterize the epidemiology of bacteremia occurring early post transplant, and to identify factors associated with infection due to multi-drug-resistant (MDR) Gram-negative isolates. MDR was defined as an isolate with resistance to at least two of the following: third- or fourth-generation cephalosporins, carbapenems or piperacillin-tazobactam. Among 411 HSCT, fever occurred in 333, and 91 developed bacteremia (118 isolates): 47% owing to Gram-positive, 37% owing to Gram-negative, and 16% caused by Gram-positive and Gram-negative bacteria. Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%) and Escherichia coli (17%) accounted for the majority of Gram-negative isolates, and 37% were MDR. These isolates were recovered from 20 patients, representing 5% of all 411 HSCT and 22% of the episodes with bacteremia. By multivariate analysis, treatment with third-generation cephalosporins (odds ratio (OR) 10.65, 95% confidence interval (CI) 3.75–30.27) and being at one of the hospitals (OR 9.47, 95% CI 2.60–34.40) were associated with infection due to MDR Gram-negative isolates. These findings may have important clinical implications in the decision of giving prophylaxis and selecting the empiric antibiotic regimen.Bone Marrow Transplantation (2007) 39, 775–781; doi:10.1038/sj.bmt.1705677; published online 16 April 2007 [ABSTRACT FROM AUTHOR]

In addition to the reduction method, we present a novel application of Jacobi’s last multiplier for finding Lie symmetries of ordinary differential equations algorithmically. These methods and Lie symmetries allow unveiling the hidden linearity of certain nonlinear equations that are relevant in physics. We consider the Einstein-Yang-Mills equations and Calogero’s many-body problem in the plane as examples. [ABSTRACT FROM AUTHOR]

The study presented here was performed in order to create a rule that identifies subjects at high risk for invasive candidiasis in the intensive care setting. Retrospective review and statistical modelling were carried out on 2,890 patients who stayed at least 4 days in nine hospitals in the USA and Brazil; the overall incidence of invasive candidiasis in this group was 3% (88 cases). The best performing rule was as follows: Any systemic antibiotic (days 1–3) OR presence of a central venous catheter (days 1–3) AND at least TWO of the following—total parenteral nutrition (days 1–3), any dialysis (days 1–3), any major surgery (days −7–0), pancreatitis (days −7–0), any use of steroids (days −7–3), or use of other immunosuppressive agents (days −7–0). The rate of invasive candidiasis among patients meeting the rule was 9.9%, capturing 34% of cases in the units, with the following performance: relative risk 4.36, sensitivity 0.34, specificity 0.90, positive predictive value 0.01, and negative predictive value 0.97. The rule may identify patients at high risk of invasive candidiasis. [ABSTRACT FROM AUTHOR]

In the recent literature, several equations have been studied with purported new approaches because the authors claim that these equations were not amenable to exact treatment using known methods. But we show that all these equations have sufficient Lie point symmetries to make them integrable by quadrature, if not linearizable. When one gets a “miraculous haul of fishes,” namely, exact methods of solution, first integrals, even linearization, then Lie symmetries shall be found. Lie group analysis was and should still be considered an essential tool for anyone who wants to solve equations of relevance in physics and other scientific fields. [ABSTRACT FROM AUTHOR]

Engraftment syndrome (ES) is an increasingly reported complication of hematopoietic stem cell transplantation (HSCT). In order to better characterize the clinical criteria for the diagnosis of ES, we retrospectively analyzed 125 autologous HSCT recipients. ES was first defined as the presence of noninfectious fever plus skin rash. Patients with and without these findings were compared (univariate and multivariate analyses) regarding the presence of weight gain, hypoalbuminemia, pulmonary infiltrates, diarrhea, neurological manifestations and jaundice. The variables that are significantly more frequent in patients with fever and skin rash were incorporated in the definition criteria. The final diagnostic criteria were noninfectious fever plus any of the following: skin rash, pulmonary infiltrates or diarrhea. The incidence of ES was 20%. The single risk factor for ES by multivariate analysis was a diagnosis other than Hodgkin's disease (odds ratio 6.17, 95% confidence interval 1.38-27.78). Patients with ES received empirical antifungal therapy more frequently than patients without the syndrome (40 vs 19%, P=0.03), and had a longer duration of hospitalization (P=0.0007). The prospective application of these diagnostic criteria may have a favorable impact on the early diagnosis of the syndrome, with the initiation of corticosteroids and a reduction in the unnecessary use of antimicrobial agents.Bone Marrow Transplantation (2003) 31, 393-397. doi:10.1038/sj.bmt.1703855 [ABSTRACT FROM AUTHOR]

Provides information on a study that randomized patients in order to assess the effect of delaying granulocyte-colony stimulating factor administration after autologous peripheral blood progenitor cell transplantation on the duration of neutropenia. Details on the patients and methodologies used; Results and discussion.

A prospective randomized trial was performed to compare the efficacy of a regimen containing a glycopeptide versus one containing a beta-lactamase inhibitor in the treatment of febrile episodes in neutropenic patients. Fifty-eight patients received piperacillin/amikacin/teicoplanin (group 1) and 56 received piperacillin/amikacin/tazobactam (group 2). In the case of persistence of fever without microbiological documentation of the cause, teicoplanin was also given empirically in group 2 on day 4, and amphotericin B in both groups on day 6. In 114 evaluable febrile episodes, the rate of success without modification of therapy was 60 % in patients on piperacillin/amikacin/teicoplanin and 41 % in patients on piperacillin/amikacin/tazobactam (p<0.03). Eleven of 34 patients in the latter group who failed to improve eventually responded upon addition of teicoplanin. Ten and nine patients in group 1 and group 2 respectively required the addition of amphotericin B for definite improvement. There were 14 episodes of gram-positive septicemia in each group: the response rate was 100 % in group 1 and 43 % in group 2. Three episodes of gram-negative breakthrough septicemia occurred in group 1 versus no cases in group 2 (p=0.1). Three deaths occurred in each group. Piperacillin/amikacin/tazobactam may be as efficacious as piperacillin/amikacin/teicoplanin in the treatment of febrile neutropenic patients provided the regimen is modified (usually by addition of teicoplanin) in unresponsive cases. [ABSTRACT FROM AUTHOR]

Copyright of Meccanica is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Il Nuovo Cimento: B is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to assess the risk factors for breakthrough candidemia (candidemia occurring in patients receiving at least 3 days of systemic fluconazole or amphotericin B), 270 cases of candidemia occurring in two tertiary hospitals were analyzed. Using multivariate analysis, profound neutropenia (<100/mm3) (odds ratio [OR], 9.14), use of corticosteroids (OR, 3.17), and heavy antibiotic exposure (previous use of 2 or more antibiotics for at least 14 days) (OR, 2.93) were identified as risk factors. Neither the susceptibility of the isolates nor the presence of a catheter was found to be a risk factor. These data suggest that gastrointestinal colonization plays a major role in the development of breakthrough candidemia. [ABSTRACT FROM AUTHOR]

Fusarium infection is increasingly reported in immunocompromised patients. The role of central venous catheters as potential portals of entry for Fusarium is possibly underestimated. Four cases of catheter-related fusarial infection in children with acute leukemia or a solid tumor are described. These patients had an excellent response to removal of the central venous catheter and treatment with amphotericin B. [ABSTRACT FROM AUTHOR]

Three cases are reported of disseminated infection due to Fusarium species in severely neutropenic patients. The clinical findings in all patients included fever, painful disseminated nodular skin lesions and severe myalgia. The outcome was fatal despite early administration of amphotericin B. The portal of entry of the organism was probably the nasal sinus in two cases. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor referencing a paper by Pérez-Simón et al on the use of meropenem as antibacterial prophylaxis after allogenic stem cell transplantations. Details of evaluation by the author of the paper; Abandonment of most strategies on the subject because variables were not influenced by these measures; Observation of gram-negative resistance in stem cell transplant recipients; Emphasis on strong discouragement for this strategy of limited value.

Focuses on a study on autologous peripheral blood proginetor cell transplantations performed between March 1996 and March 1998. Underlying diseases; Conclusion on the use of granulocyte-colony stimulating factor in patients infused with lower counts of precursor cells.