A 1D continuum model for beams with pantographic microstructure: asymptotic micro-macro identification and numerical results

In the standard asymptotic micro-macro identification theory, starting from a De Saint-Venant cylinder, it is possible to prove that, in the asymptotic limit, only flexible, inextensible, beams can be obtained at the macro-level. In the present paper we address the following problem: is it possible to find a microstructure producing in the limit, after an asymptotic micro-macro identification procedure, a continuum macro-model of a beam which can be both extensible and flexible? We prove that under certain hypotheses, exploiting the peculiar features of a pantographic microstructure, this is possible. Among the most remarkable features of the resulting model we find that the deformation energy is not of second gradient type only because it depends, like in the Euler beam model, upon the Lagrangian curvature, i.e. the projection of the second gradient of the placement function upon the normal vector to the deformed line, but also because it depends upon the projection of the second gradient of the placement on the tangent vector to the deformed line, which is the elongation gradient. Thus, a richer set of boundary conditions can be prescribed for the pantographic beam model. Phase transition and elastic softening are exhibited as well. Using the resulting planar 1D continuum limit homogenized macro-model, by means of FEM analyses, we show some equilibrium shapes exhibiting highly non-standard features. Finally, we conceive that pantographic beams may be used as basic elements in double scale metamaterials to be designed in future

Pantographic beam: a complete second gradient 1D-continuum in plane

International audienceThere is a class of planar 1D-continua which can be described exclusively by their placement functions which in turn are curves in a two-dimensional space. In contrast to the Elastica for which the deformation energy depends on the projection of the second gradient to the normal vector of the placement function, i.e. the material curvature, the proposed continuum does also depend on the projection onto the tangent vector, introduced as the stretch gradient. Thus, the deformation energy takes into account the complete second gradient of the placement function. In such a model, non-standard boundary conditions and more generalized forces such as double forces do appear. The deformation energy of the continuum is obtained by applying a heuristic homogenization procedure to a family of slender discrete pantographic structures constituted by extensional and rotational springs. Within the homogenization process, the overall length of the system is kept fixed, the number of the periodically appearing sub-systems, called cells, is increased, and the stiffnesses are appropriately scaled. For two examples, we numerically compare the family of discrete systems with the continuum. The analysis shows that the continuum represents the behaviour of the discrete system already for a relatively moderate number of cells. In particular, the behaviour of the deformation energy error between the discrete and the continuum models when the number of cells tends to infinity is determined by the homogenization process

Effects of caspofungin against Candida guilliermondii and Candida parapsilosis.

The in vitro activity of caspofungin (CAS) was investigated against 28 yeast isolates belonging to Candida albicans (n = 5), Candida guilliermondii (n = 10), and Candida parapsilosis (n = 13). CAS MICs obtained by broth dilution and Etest methods clearly showed a rank order of susceptibility to the echinocandin compound with C. albicans > C. parapsilosis > C. guilliermondii. Similarly, time-kill assays performed on selected isolates showed that CAS was fungistatic against C. albicans and C. parapsilosis, while it did not exert any activity against C. guilliermondii. In a murine model of systemic candidiasis, CAS given at doses as low as 1 mg/kg of body weight/day was effective at reducing the kidney burden of mice infected with either C. albicans or C. guilliermondii isolates. Depending on the isolate tested, mice infected with C. parapsilosis responded to CAS given at 1 and/or 5 mg/kg/day. However, the overall CFU reduction for C. guilliermondii and C. parapsilosis was approximately 100-fold less than that for C. albicans. Our study shows that CAS was active in experimental systemic candidiasis due to C. guilliermondii and C. parapsilosis, but this activity required relatively high drug dosages

Fungicidal activity and PK/PD of caspofungin as tools to guide antifungal therapy in a fluconazole-resistant C. parapsilosis candidemia

Candida parapsilosis may be responsible for bloodstream infections (BSI) and it is characterised by an increased incidence of fluconazole resistance. A 75-year old woman with severe comorbidities received the insertion of a peripherally inserted central venous catheter. Fluconazole did not prevent a C. parapsilosis BSI hence caspofungin was started after a nephrotoxic first-line treatment with amphotericin B. The ratio of peak plasma concentration over the minimum inhibitory concentration (Cmax/MIC) was adopted to maximise efficacy of caspofungin. MIC and plasma Cmax values were obtained by broth microdilution and LC-MS, respectively. Interestingly, daily doses of 1 mg/kg (total daily dose, 50 mg) allowed the achievement of Cmax/MIC values > 10. The optimised regimen was safe and effective, leading to negative blood culture at day 8. The patient was discharged home at day 21. Therefore, individualised dosing regimens of caspofungin may be effective and safe even in the case of C. parapsilosis BSI

Statistical analyses of correlation between fluconazole MICs for Candida spp. assessed by standard methods set forth by the European Committee on Antimicrobial Susceptibility Testing (E.Dis. 7.1) and CLSI (M27-A2).

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Subcommittee on Antifungal Susceptibility Testing recently published a standard for determining the susceptibility of fermentative yeasts to antifungals. From the beginning, the EUCAST and its North American counterpart, the CLSI, decided to work together in order to establish common standards. As part of this exercise, the susceptibility of a set of 475 yeast isolates was tested by both standards. The intraclass correlation coefficient and the equations defining the linear regression between both methods were estimated. Both methods produced very similar results, with an intraclass correlation coefficient of 0.954 (0.945 to 0.962), although linear regression analysis shows that the EUCAST standard resulted in slightly lower MICs. There were only eight isolates showing at least four twofold dilution MIC differences between both standards. After 24 h of incubation, the MICs obtained by the CLSI method were equivalent to those obtained by the EUCAST standard. In summary, both methods produce very similar MICs, indicating that methodology does not pose any obstacle to obtaining uniform standards for antifungal susceptibility testing of yeast

Correlation of Serum Cystatin C with Glomerular Filtration Rate in Patients Receiving Platinum-Based Chemotherapy

Objectives. Serum cystatin C seems to be an accurate marker of glomerular filtration rate (GFR) compared to serum creatinine. The aim of this work was to explore the possibility of using serum cystatin C instead of serum creatinine to early predict renal failure in cancer patients who received platinum based chemotherapy. Design and Methods. Serum creatinine, serum cystatin C concentrations, and GFR were determined simultaneously in 52 cancer patients received carboplatin-based or cisplatin-based chemotherapy. Serum creatinine was assayed on Cobas C6000-Roche, serum cystatin C assay was performed on AIA 360-Tosoh, and GFR was determined in all patients, before the first cycle of chemotherapy and before the subsequent administrations. Results. In the overall series, for the prediction of a fall of GFR < 80 mL/min/1.73 m2, the AUC of the ROC curve for cystatin C was 0,667 and the best threshold was 1.135 mg/L (sensitivity 90.5%, specificity 61.1%). For a GFR fall < 60 mL/min/1.73 m2, the AUC of ROC curve for cystatin C was 74.3% and the best threshold was 1.415 mg/L (sensitivity 66.7%, specificity 73.2%). Conclusions. Baseline cystatin C values were not able to predict renal failure during subsequent treatment. In conclusion, serum cystatin C is not a reliable early marker to efficiently predict renal failure in patients receiving chemotherapy

Cefiderocol treatment for carbapenem-resistant Acinetobacter baumannii infection in the ICU during the COVID-19 pandemic: a multicentre cohort study

open16noFunding: This study was carried out as part of our routine work and supported by internal funding.Objectives: To analyse the impact of cefiderocol use on outcome in patients admitted to the ICU for severe COVID-19 and further diagnosed with carbapenem-resistant Acinetobacter baumannii (CR-Ab) infection.Methods: Retrospective multicentre observational study was performed at four Italian hospitals, from January 2020 to April 2021. Adult patients admitted to ICU for severe COVID-19 and further diagnosed with CR-Ab infections were enrolled. Patients treated with cefiderocol, as compassionate use, for at least 72 h were compared with those receiving alternative regimens. Primary endpoint was all-cause 28 day mortality. The impact of cefiderocol on mortality was evaluated by multivariable Cox regression model.Results: In total, 107 patients were enrolled (76% male, median age 65 years). The median time from ICU admission to CR-Ab infection diagnosis was 14 (IQR 8-20) days, and the main types of CR-Ab infections were bloodstream infection (58%) and lower respiratory tract infection (41%). Cefiderocol was administered to 42 patients within a median of 2 (IQR 1-4) days after CR-Ab infection diagnosis and as monotherapy in all cases. The remaining patients received colistin, mostly (82%) administered as combination therapy. All-cause 28 day mortality rate was 57%, without differences between groups (cefiderocol 55% versus colistin 58% P = 0.70). In multivariable analysis, the independent risk factor for mortality was SOFA score (HR 1.24, 95% CI 1.15-1.38, P &lt; 0.001). Cefiderocol was associated with a non-significant lower mortality risk (HR 0.64, 95% CI 0.38-1.08, P = 0.10).Conclusions: Our study confirms the potential role of cefiderocol in the treatment of CR-Ab infection, but larger clinical studies are needed.openPascale, Renato; Pasquini, Zeno; Bartoletti, Michele; Caiazzo, Luca; Fornaro, Giacomo; Bussini, Linda; Volpato, Francesca; Marchionni, Elisa; Rinaldi, Matteo; Trapani, Filippo; Temperoni, Chiara; Gaibani, Paolo; Ambretti, Simone; Barchiesi, Francesco; Viale, Pierluigi; Giannella, MaddalenaPascale, Renato; Pasquini, Zeno; Bartoletti, Michele; Caiazzo, Luca; Fornaro, Giacomo; Bussini, Linda; Volpato, Francesca; Marchionni, Elisa; Rinaldi, Matteo; Trapani, Filippo; Temperoni, Chiara; Gaibani, Paolo; Ambretti, Simone; Barchiesi, Francesco; Viale, Pierluigi; Giannella, Maddalen

Penerapan Metode Peer Teaching Untuk Meningkatkan Hasil Belajar Kognitif Siswa Pada Mata Pelajaran Pendidikan Agama Islam Materi Puasa Wajib dan Puasa Sunah : Penelitian Tindakan Kelas di Kelas VIII-G (Delapan) SMPN 31 Bandung

Masalah yang sangat menonjol yang di hadapi dalam pelajaran PAI yang bermula dari fenomena yang muncul di lapangan yaitu hasil belajar siswa yang masih rendah. Hal ini terlihat dari hasil belajar siswa dan hasil ulangan siswa masih banyak yang berada di bawah KKM 76 hampir 70%. Salah satu faktor yang mempengaruhi hasil belajar siswa adalah metode yang sesuai. Oleh karena itu, diperlukan metode yang baru dan interaktif, agar pemahaman siswa pada materi pelajaran menjadi optimal sehingga hasil belajar mereka pun dapat meningkat sesuai dengan yang diharapkan. Penelitian ini bertujuan untuk mengetahui (1) Hasil belajar kognitif siswa sebelum diterapkan metode Peer Teaching pada mata pelajaran PAI siswa kelas VIII-G; (2) Proses pembelajaran siswa kelas VIII-G dengan menggunakan metode Peer Teaching pada mata pelajaran PAI siswa kelas VIII-G; (3) Hasil belajar kognitif siswa kelas VIII-G pada mata pelajaran PAI setelah diterapkan metode Peer Teaching. Metode peer teaching dinilai dapat dimanfaatkan sebaik-baiknya dalam pelajaran Pendidikan Agama Islam. Kelebihan dari metode ini adalah (1) Meningkatkan motivasi belajar siswa; (2) Meningkatkan kualitas dan proses pembelajaran; (3) Meningkatkan hasil belajar. Penelitian ini merupakan Penelitian Tindakan Kelas yang dilakukan dalam 3 siklus. Setiap siklus terdiri dari 1 pertemuan dengan tahapan-tahapan (1) Perencanaan; (2) Tindakan; (3) Observasi; (4) Refleksi. Tahapan-tahapan ini dilakukan untuk meningkatkat hasil belajar kognitif siswa pada mata pelajaran PAI materi Puasa Wajib dan Puasa Sunah. Setelah melakukan penelitian, disimpulkan bahwa (1) hasil belajar kognitif siswa sebelum diterapkannya metode Peer Teaching masih banyak siswa yang mendapatkan nilai di bawah rata-rata KKM, (2) Proses pembelajaran dengan menggunakan metode Peer Teaching setiap siklusnya mengalami peningkatan yang sangat signifikan, dengan kegiatan intinya adalah siswa di bantu oleh temannya sendiri ketika belajar di kelas dan (3) Hasil belajar kognitif siswa setelah diterapkan metode Peer Teaching yaitu setiap siklusnya mengalami peningkatan, terlihat pada siklus I dengan rata-rata 72.37 termasuk kategori baik, ketuntasan belajar klasikal sebesar 36.84% dengan jumlah 14 siswa tuntas belajar, siklus II nilai rata-rata meningkat menjadi 80 termasuk kategori sangat baik, sehingga nilai rata-rata dari siklus I ke siklus II meningkat sebesar 7.63%, ketuntasan belajar klasikal sebesar 86.84% dengan jumlah 33 siswa tuntas belajar sehingga ketuntasan belajar klasikal dari siklus I dan II meningkat sebesar 50%, dan siklus III terjadi peningkatan nilai rata-rata yang signifikan menjadi 96.05 termasuk kategori sangat baik, sehingga nilai rata-rata dari siklus II ke siklus III meningkat sebesar 16.05% semua siswa masuk pada kategori tuntas sehingga persentasi kelulusan 100%. Dengan demikian, pembelajaran Pendidikan Agama Islam dengan menggunakan metode peer teaching dapat meningkatkan hasil belajar kognitif siswa

Evaluation multicentrique d'une méthode EUCAST pour tester la sensibilité antifongique des dermatophytes produisant des spores

Background: Terbinafine resistance is increasingly reported in Trichophyton rubrum and Trichophyton interdigitale rendering susceptibility testing important particularly in non-responding cases. We performed a multicentre evaluation of a recently proposed modified EUCAST method implementing medium supplemented with chloramphenicol and cycloheximide (CC) to avoid contamination. Materials/methods: A blinded panel of wild-type and squalene epoxidase (SQLE) target gene mutant T. rubrum and T. interdigitale strains were distributed to 10 European laboratories. Susceptibility to terbinafine, itraconazole, voriconazole and amorolfine) were performed according to the E.Def 9.3.1 method with and without addition of chloramphenicol and cycloheximide (final concentrations 50 mg/L and 300 mg/L, respectively). Plates were incubated at 25 °C (one laboratory used 30 °C) for 5-7 days until sufficient growth. MICs were determined visually (ignoring trailing growth for itraconazole) and spectrophotometrically with 90% and 50% endpoints yielding a total of 7,829 MICs. A. flavus ATCC 204304 and A. flavus CNM-CM1813 were included as controls. Results: 100%/96% (voriconazole) and 84%/84% (itraconazole) MIC determinations fell within the QC ranges for the two QC strains, respectively, and 96%/92% terbinafine MICs fell in a 0.25-1 mg/L 3 two-fold-dilution range suggesting a high interlaboratory reproducibility. Across the six methods, the number of terbinafine MEs varied from 2 (2.6%) to 5 (6.6%) for T. rubrum and between 0 and 2 (2.0%) for T. interdigitale (lowest for the CC-method (2.6%-4.4%/ 0-1% for T. rubrum/T. interdigitale). The difference between the modes for the wt and mutant population were ≥7 two-fold-dilutions in all cases (Table). If excluding a I121M/V237I T. rubrum mutant, and two mixed T. interdigitale strains, the number of VMEs were CC visual: T. rubrum: 1/77 (1.3%), CC spec-90%: 3/68 (4.4%) and CC spec-50%: 1/76 (1.3%), and none for T. interdigitale. The activity of voriconazole, itraconazole and amorolfine were quite uniform against T. rubrum and T. interdigitale, but unacceptably wide MIC ranges were found for the visual and spec-90% inhibition methods for itraconazole (data not shown). Conclusions: Although none of the laboratories perform dermatophyte testing at a regular basis an acceptable interlaboratory agreement and good separation between SQLE wt and mutants were found, suggesting a robust performance of the proposed method

GINGER

In this paper, we outline the scientific objectives, the experimental layout, and the collaborations envisaged for the GINGER (Gyroscopes IN GEneral Relativity) project. The GINGER project brings together different scientific disciplines aiming at building an array of Ring Laser Gyroscopes (RLGs), exploiting the Sagnac effect, to measure continuously, with sensitivity better than picorad/ s, large bandwidth (ca. 1 kHz), and high dynamic range, the absolute angular rotation rate of the Earth. In the paper, we address the feasibility of the apparatus with respect to the ambitious specifications above, as well as prove how such an apparatus, which will be able to detect strong Earthquakes, very weak geodetic signals, as well as general relativity effects like Lense-Thirring and De Sitter, will help scientific advancements in Theoretical Physics, Geophysics, and Geodesy, among other scientific fields.Comment: 21 pages, 9 figure