Thermal Stability, Blocking Regime and Superparamagnetic Behavior in Mn-Al-C Melt Spun Ribbons

Alloys possessing nominal compositions Mn53Al45C2 and Mn52Al46C2 were prepared by the melt spinning method and were subjected to complex structural, morphological and magnetic investigations. As these alloys can exhibit tetragonal L10-type and τ phase, they have good potential as rare earth (RE)—free magnets. It is, therefore, important to monitor the ε–τ phase transformation and the stability and the magnetic features of the tetragonal phase in an entire temperature interval. By using synchrotron X-ray diffraction, it has been proven that the ε–τ phase transformation occurs gradually, with the τ phase becoming predominant only after 450 °C. Moreover, this phase has been proven to be quite stable without any grain growth even at the highest temperature investigated at 800 °C. Low temperature behavior was thoroughly investigated by using a complex combination of major and minor hysteresis loops combined with the zero field cooled-field cooled magnetization protocols (ZFC-FC). Two different regimes, blocking and superparamagnetic, were documented. A spin reorientation transition was proven to occur at 55 K while a maximum magnetization observed in ZFC-FC curves proved that at about 75 K, a transition from ferro to superparamagnetic state occurs. The existence of a blocking regime below 55 K that is characteristic to nanogranular systems with superparamagnetic behavior has shown further development towards obtaining RE-free magnets

The Pitfalls of Febrile Jaundice. A Case Report

Jaundice in sepsis is usually caused by cholestasis, and its onset can precede other manifestations of the infection. Inflammation-induced cholestasis is a common complication in patients with an extrahepatic infection or those with inflammatory processes. We describe the case of a 47 years old female who presented with low back pain and paravertebral muscular contracture. She subsequently developed a cholestatic syndrome with clinical manifestations such as jaundice, followed by fever and sepsis with multiple organ dysfunction. Initially labeled as biliary sepsis, the diagnosis was crucially reoriented as the blood cultures were positive for Streptococcus pyogenes and the magnetic resonance imaging (MRI) findings suggested spondylodiscitis as well as a paravertebral abscess

Magnetism and ε-τ Phase Transformation in MnAl-Based Nanocomposite Magnets

Melt spun ribbons of Mn53Al45C2 and Mn52Al46C2 have been synthesized by rapid quenching of the melt with the purpose of monitoring the ε-τ phase transformation to show technologically feasible ways to increase magnetic parameters and to illustrate the viability of these alloys as the next generation of rare earth (RE)-free magnets. By differential scanning calorimetry (DSC), activation energies and temperatures of onset of the ε-τ phase transformation were obtained. Structural analysis was performed using X-ray diffraction (XRD) and the resulting XRD patterns were quantitatively assessed using full profile Rietveld-type analysis. Appropriate annealing was performed in order to enable the ε-τ phase transformation. While hcp ε-phase was found to be predominant in the as-cast samples, after appropriate annealing, the tetragonal τ-phase, the one that furnishes the relevant magnetic response, was found to be predominant with an abundance of about 90%. The data suggested a mechanism of hcp ε-phase decomposition controlled by the segregation towards the interfacial regions, having the rate of transformation governed by antiphase boundary diffusion processes. Magnetic measurements of annealed sample Mn53Al45C2, consisting of predominant tetragonal τ-phase, showed high values of magnetization and increased coercivity, consistent with an energy product of about 10 MGOe, similar with previously reported magnetization measurements, providing further insight into the realization of future class of RE-free low-cost permanent magnets

Mn-Induced Thermal Stability of L10 Phase in Fept Magnetic Nanoscale Ribbons

Magnetic nanoscale materials exhibiting the L10 tetragonal phase such as FePt or ternary alloys derived from FePt show most promising magnetic properties as a novel class of rare earth free permanent magnets with high operating temperature. A granular alloy derived from binary FePt with low Pt content and the addition of Mn with the nominal composition Fe57Mn8Pt35 has been synthesized in the shape of melt-spun ribbons and subsequently annealed at 600 °C and 700 °C for promoting the formation of single phase, L10 tetragonal, hard magnetic phase. Proton-induced X-ray emission spectroscopy PIXE has been utilized for checking the compositional effect of Mn addition. Structural properties were analyzed using X-ray diffraction and diffractograms were analyzed using full profile Rietveld-type analysis with MAUD (Materials Analysis Using Diffraction) software. By using temperature-dependent synchrotron X-ray diffraction, the disorder–order phase transformation and the stability of the hard magnetic L10 phase were monitored over a large temperature range (50–800 °C). A large interval of structural stability of the L10 phase was observed and this stability was interpreted in terms of higher ordering of the L10 phase promoted by the Mn addition. It was moreover found that both crystal growth and unit cell expansion are inhibited, up to the highest temperature investigated (800 °C), proving thus that the Mn addition stabilizes the formed L10 structure further. Magnetic hysteresis loops confirmed structural data, revealing a strong coercive field for a sample wherein single phase, hard, magnetic tetragonal L10 exists. These findings open good perspectives for use as nanocomposite, rare earth free magnets, working in extreme operation conditions

Heparin-Binding Protein (HBP), Neutrophil Gelatinase-Associated Lipocalin (NGAL) and S100 Calcium-Binding Protein B (S100B) Can Confirm Bacterial Meningitis and Inform Adequate Antibiotic Treatment

The empirical administration of antibiotics for suspected bacterial meningitis denotes a poor bacterial stewardship. In this context, the use of biomarkers can distinguish between bacterial and viral infections before deciding treatment. Our study assesses how levels of heparin-binding protein (HBP), neutrophil gelatinase-associated lipocalin (NGAL), S100 calcium-binding protein B (S100B), and neuron-specific enolase (NSE) in cerebrospinal fluid (CSF) and in blood can promptly confirm bacterial etiology and the need for antibiotic treatment. The CSF and blood levels of HBP, NGAL, S100B, and NSE of 81 patients with meningitis were measured and analyzed comparatively. Statistical sensitivity, specificity, and positive and negative predictive values were evaluated. CSF levels of HBP and NGAL and the blood level of S100B in the bacterial meningitis group were significantly higher (p < 0.05). The area under curve (AUC) for predicting bacterial meningitis was excellent for the CSF level of HBP (0.808 with 93.54% sensitivity and 80.64% specificity), good for the CSF level of NGAL (0.685 with 75.00% sensitivity and 65.62% specificity), and good for the blood level of S100B (0.652 with 65.90% sensitivity and 57.14% specificity). CSF levels of HBP and NGAL, as well as the blood level of S100B, could help discriminate between bacterial and viral meningitis before considering antibiotic treatment

THE IMPORTANCE OF CLINICAL PICTURE IN THE DIAGNOSIS OF GUILLAIN-BARRÉ SYNDROME

Guillain-Barré syndrome (GBS) is an immune-mediated peripheral polyradiculonevritis, which is clinically characterized by rapid, symmetrical progression of muscle weakness or paralysis, with or without sensitive symptoms. We report the case of a male child aged 4 years is presented for distal weakness in the lower limbs, impossibility of maintaining vertical posture, balance disorders, alternating sleepiness with episodes of psychomotor agitation and dysphonia, headache, with sudden onset about 12 hours before hospitalization. The presented case underlines the importance of accurately describing the clinical picture and evolution in establishing the diagnosis, in total or partial absence of paraclinical data. Also, the low number of cases described in medical jurnals justify the interest in investigating and publishing these cases

IMPORTANȚA TABLOULUI CLINIC ÎN DIAGNOSTICUL SINDROMULUI GUILLAIN-BARRÉ

Sindromul Guillain-Barré este o poliradiculonevrită periferică mediată imun, care se caracterizează clinic printr-o evoluție rapidă, simetrică a slăbiciunii musculare sau a paraliziei, cu sau fară simptome senzitive. Descriem cazul unui copil, de sex masculin, în vârstă de 4 ani, care se prezintă pentru slăbiciune distală la nivelul membrelor inferioare, imposibilitatea menținerii ortostatismului, tulburări de echilibru, somnolenţă alternând cu episoade de agitaţie psihomotorie şi disfonie, cefalee, simptomatologie ce a debutat cu 12 ore anterior internării. Datele clinice și de laborator, precum și evoluția bolii au pledat pentru diagnosticul de sindrom Guillain-Barré. Sub tratamentul efectuat, evoluția a fost favorabilă. Cazul descris subliniază importanța descrierii cu exactitate a tabloului clinic și a evoluţiei pentru stabilirea diagnosticului, în absenţa totală sau parțială a datelor paraclinice. Totodată, incidența scăzută a cazurilor descrise în literatură justifică importanța raportării acestuia

The Clash of the Titans: COVID-19, Carbapenem-Resistant <i>Enterobacterales,</i> and First <i>mcr-1</i>-Mediated Colistin Resistance in Humans in Romania

(1) Background: Antibiotic resistance and coronavirus disease-19 (COVID-19) represent a dual challenge in daily clinical practice, inducing a high burden on public health systems. Hence, we aimed to dynamically evaluate the impact of COVID-19 on patients with carbapenem-resistant Enterobacterales (CRE) urinary tract infections (UTIs), as well as the antibiotic resistance trends after the onset of the pandemic. (2) Methods: We conducted a prospective study including patients with CRE UTIs who were enrolled both pre- and during the pandemic from 2019 to 2022. We further performed a standardized and comparative clinical, paraclinical, and microbiological assessment between patients with and without COVID-19. (3) Results: A total of 87 patients with CRE UTIs were included in this study (46 pre-pandemic and 41 during the pandemic, of which 21 had associated Severe Acute Respiratory Syndrome Coronavirus-2 infection). Klebsiella pneumoniae was the main etiological agent of the UTIs, with the majority of strains (82.7%) being carbapenemase producers (mainly OXA-48 producers), while five of the 34 colistin-resistant isolates were harboring the mobile colistin resistance-1 (mcr-1) gene. COVID-19 patients presented a significantly worse outcome with higher rates of intensive care unit (ICU) admissions (66.7% for COVID patients vs. 18.2% for non-COVID patients, p p K. pneumoniae, impaired liver and kidney function, and an inappropriate initial empiric antibiotic therapy. (4) Conclusions: COVID-19 showed a pronounced negative impact on patients with CRE UTIs, with significantly longer hospitalizations and higher ICU admissions and mortality rates

Tuberculous Meningitis in Children and Adults: A 10-Year Retrospective Comparative Analysis.

Tuberculous meningitis (TBM) is the most lethal form of Mycobacterium tuberculosis infection, which has a high rate of neurological complications and sequelae.Our study offers a real-world infectious disease clinic perspective, being thus representative for the clinical environment of developing countries.We performed a retrospective analysis of the 127 adult and 77 pediatric cases diagnosed with TBM in the Infectious Disease Hospital of the School of Medicine of Iasi, Romania between 2004-2013.Definite diagnosis of TBM was established in 31% of children but in only 20% of adults (p = 0.043). A contact with an individual with pulmonary tuberculosis was documented in 30% of children vs. 13% of adults (p = 0.0007). Coma occurred in 19% of patients (similar in children and adults); other consciousness abnormalities were seen in 27% of children and in 72% of adults (p = 0.000001). Cranial nerve palsies occurred prior to therapy in 9% of cases (12% vs 7% of children and adults, respectively, p>0.05), and developed 2-7 days after treatment initiation in 10% (12 vs 9%). CSF cultures were positive for M. tuberculosis in 24% of patients (31% vs. 20%, p>0.05). Overall mortality was 7.35%, similar for children and adults. Yet, permanent neurological sequelae, which were seen in 23% of patients occurred significantly more frequent in children vs. adults (36% vs. 14%, respectively, p = 0.0121). In conclusion, our retrospective analysis on a significant number of cases of TBM identified striking differences between children and adults: while children were in an earlier stage at the admission, they associated a higher frequency of neurological sequelae and miliary pattern, and they were more likely to have normal CSF protein levels and positive cultures of CSF

Syndecan-1: From a Promising Novel Cardiac Biomarker to a Surrogate Early Predictor of Kidney and Liver Injury in Patients with Acute Heart Failure

(1) Background: Acute heart failure (HF) represents a complex clinical syndrome burdened by increased mortality and a high rate of systemic complications. Although natriuretic peptides (e.g., NT-proBNP) currently represent the diagnostic and prognostic gold standard in acute HF, those molecules do not accurately reflect all the pathophysiological mechanisms involved in the progression of this pathology when determined independently. Therefore, the current paradigm tends to focus on a multi-marker approach for the risk stratification of patients with acute HF. Syndecan-1 is a less studied biomarker in cardiovascular diseases; its assessment in patients with acute HF being potentially able to reflect the myocardial pathological changes, such as fibrosis, inflammation, endothelial dysfunction or global wall stress. (2) Methods: We conducted a single center prospective study that enrolled 173 patients (120 patients admitted for acute HF, compared to 53 controls with stable chronic HF). A complete standardized clinical, echocardiography and laboratory evaluation was performed at admission, including serum samples for the determination of syndecan-1 by the enzyme-linked immunosorbent assay (ELISA) method. (3) Results: The serum concentration of syndecan-1 was significantly higher in patients with acute HF, compared to controls [121.4 (69.3–257.9) vs. 72.1 (41.4–135.8) ng/mL, p = 0.015]. Syndecan-1 was a significant predictor for the diagnosis of acute HF, expressed by an area under the curve (AUC) of 0.898, similar to NT-proBNP (AUC: 0.976) or cardiac troponin (AUC: 0.839). Moreover, syndecan-1 was independently associated with impaired kidney and liver function at admission, being also a predictor for early, subclinical organ dysfunction in patients with normal biological parameters at admission. When included in the multi-marker model, syndecan-1 levels influenced mortality more significantly than NT-proBNP or troponin. A multivariable regression including syndecan-1, NT-proBNP and troponin provided additional prognostic value compared to each independent biomarker. (4) Conclusions: Syndecan-1 can be considered a promising novel biomarker in acute HF, exhibiting adequate diagnostic and prognostic value. Additionally, syndecan-1 can be used as a surrogate biomarker for non-cardiac organ dysfunction, as its highs levels can accurately reflect early acute kidney and liver injury