There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

We have previously demonstrated that a clinical model can be safely used in a management strategy in patients with suspected pulmonary embolism (PE). We sought to simplify the clinical model and determine a scoring system, that when combined with D-dimer results, would safely exclude PE without the need for other tests, in a large proportion of patients. We used a randomly selected sample of 80% of the patients that participated in a prospective cohort study of patients with suspected PE to perform a logistic regression analysis on 40 clinical variables to create a simple clinical prediction rule. Cut points on the new rule were determined to create two scoring systems. In the first scoring system patients were classified as having low, moderate and high probability of PE with the proportions being similar to those determined in our original study. The second system was designed to create two categories, PE likely and unlikely. The goal in the latter was that PE unlikely patients with a negative D-dimer result would have PE in less than 2% of cases. The proportion of patients with PE in each category was determined overall and according to a positive or negative SimpliRED D-dimer result. After these determinations we applied the models to the remaining 20% of patients as a validation of the results. The following seven variables and assigned scores (in brackets) were included in the clinical prediction rule: Clinical symptoms of DVT (3.0), no alternative diagnosis (3.0), heart rate >100 (1.5), immobilization or surgery in the previous four weeks (1.5), previous DVT/PE (1.5), hemoptysis (1.0) and malignancy (1.0). Patients were considered low probability if the score was 4.0. 7.8% of patients with scores of less than or equal to 4 had PE but if the D-dimer was negative in these patients the rate of PE was only 2.2% (95% CI = 1.0% to 4.0%) in the derivation set and 1.7% in the validation set. Importantly this combination occurred in 46% of our study patients. A score of

Derivation of a Simple Clinical Model to Categorize Patients Probability of Pulmonary Embolism: Increasing the Models Utility with the SimpliRED D-dimer

Managing patients for suspected pulmonary embolism on the basis of pretest probability and D-dimer test result is safe and decreases the need for diagnostic imaging.

Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer.

Large-scale electrolysis of water for hydrogen generation requires better catalysts to lower the kinetic barriers associated with the oxygen evolution reaction (OER). Although most OER catalysts are based on crystalline mixed-metal oxides, high activities can also be achieved with amorphous phases. Methods for producing amorphous materials, however, are not typically amenable to mixed-metal compositions. We demonstrate that a low-temperature process, photochemical metal-organic deposition, can produce amorphous (mixed) metal oxide films for OER catalysis. The films contain a homogeneous distribution of metals with compositions that can be accurately controlled. The catalytic properties of amorphous iron oxide prepared with this technique are superior to those of hematite, whereas the catalytic properties of a-Fe100-y-zCoyNizOx are comparable to those of noble metal oxide catalysts currently used in commercial electrolyzers.

https://science.sciencemag.org/content/sci/early/2013/03/27/science.1233638.full.pdf

Photochemical Route for Accessing Amorphous Metal Oxide Materials for Water Oxidation Catalysis

PURPOSE: To prospectively evaluate pulmonary magnetic resonance (MR) angiography as a diagnostic examination for acute pulmonary embolism (PE). MATERIALS AND METHODS: Thirty-six consecutive patients (19 women, 17 men; age range, 28–84 years) underwent pulmonary digital subtraction angiography (DSA) and pulmonary MR angiography. MR angiograms were obtained during suspended respiration and the pulmonary arterial phase of a gadolinium-based contrast medium injection. A steady-state gradient-recalled-echo sequence with free induction decay sampling was used. DSA studies were interpreted for the presence of acute PE by two independent radiologists; an adjudicator made the final decision on discordant interpretations. RESULTS: By using DSA, a total of 19 acute pulmonary emboli were depicted in 13 patients. Prospectively, 13 of these emboli were depicted by using MR angiography. MR angiography missed six emboli: Four required the DSA adjudicator to make the decision, and one was in a patient whose MR angiogram w...

Acute pulmonary embolism: diagnosis with MR angiography.

On the synthesis and optical absorption studies of nano-size magnesium oxide powder

In its wake, the COVID-19 pandemic has ushered in a surge in the number of cases of mucormycosis. Most cases are temporally linked to COVID-19; hence, the entity is described as COVID-19-associated mucormycosis (CAM). The present systematic review was undertaken to provide an up-to-date summary of the hitherto available literature on CAM. PubMed, Scopus and Google Scholar databases were systematically searched using appropriate keywords till 14 May 2021, to identify case reports/case series pertaining to mucormycosis in patients with COVID-19. Relevant data extracted included demographic characteristics, comorbidity profile, clinical category of mucormycosis, glucocorticoid use, treatment offered and patient outcome. We identified 30 case reports/case series, pooling data retrieved from 99 patients with CAM. Most cases were reported from India (72%). The majority of the patients was male (78%) and had diabetes mellitus (85%). A prior history of COVID-19 was present in 37% patients with mucormycosis developing after an initial recovery. The median time interval between COVID-19 diagnosis and the first evidence of mucormycosis infection or CAM diagnosis was 15 days. Glucocorticoid use was reported in 85% of cases. Rhino-orbital mucormycosis was most common (42%), followed by rhino-orbito-cerebral mucormycosis (24%). Pulmonary mucormycosis was observed in 10 patients (10%). The mortality rate was 34%; the use of adjunct surgery, which was undertaken in 81% of patients, was associated with better clinical outcomes (p < .001). In conclusion, CAM is an emerging problem necessitating increased vigilance in COVID-19 patients, even those who have recovered. CAM portends a poor prognosis and warrants early diagnosis and treatment.

COVID-19-associated mucormycosis: An updated systematic review of literature.

Nanocrystallites of tricobalt tetraoxide (Co 3 O 4 ) have been synthesized by sol–gel process using cobalt acetate tetrahydrate, oxalic acid as precursors and ethanol as a solvent. The process comprises of gel formation, drying at 80 °C for 24 h to obtain cobalt oxalate dihydrate (α-CoC 2 O 4 ·2H 2 O) followed by calcination at or above 400 °C for 2 h in air. These results combined with thermal analysis have been used to determine the scheme of oxide formation. The room temperature optical absorption spectra exhibits blue shift in both (i) ligand to metal (p(O 2− ) → e g (Co 3+ ), 3.12 eV), and (ii) metal to metal charge transfer transitions (a) t 2g (Co 3+ ) → t 2 (Co 2+ ), 1.77 eV, (b) t 2 (Co 2+ ) → e g (Co 3+ ), 0.95 eV together with the d–d transitions (0.853 and 0.56 eV) within the Co 2+ tetrahedra. The temperature dependent ac electrical and dielectric properties of these nanocrystals have been studied in the frequency range 100 Hz to 15 MHz. There are two regimes distinguishing different temperature dependences of the conductivity (70–100 K and 200–300 K). The ac conductivity in both the temperature regions is explained in terms of nearest neighbor hopping (NNH) mechanism of electrons. The carrier concentration measured from the capacitance ( C )–voltage ( V ) measurements is found to be 1.05 × 10 16  m −3 . The temperature dependent dc magnetic susceptibility curves under zero field cooled (ZFC) and field cooled (FC) conditions exhibit irreversibilities whose blocking temperature ( T B ) is centered at 35 K. The observed Neel temperature ( T N  ∼ 25 K) is significantly lower than the bulk Co 3 O 4 value ( T N  = 40 K) possibly due to the associate finite size effects.

Optical, electrical and magnetic properties of Co3O4 nanocrystallites obtained by thermal decomposition of sol–gel derived oxalates

In this paper, single-phase multiferroic ceramics of (1 − x) BaTiO3 − x BiFeO3 (BT − x BFO) were synthesized by solid-solution method in the wide range of material composition (x = 0.025 – 1.0). The changes in crystal structure were confirmed via X-ray diffractions (XRD) and atomic pair distribution functions (PDFs). The room-temperature ME coupling was found to exhibit significant magnitude in the narrow composition window (x = 0.71 – 0.8) where the average crystal structure was found to be rhombohedral. Especially, the BT – 0.725 BFO ceramics containing local monoclinic distortions within rhombohedral phase were found to exhibit high room-temperature ME coefficient (αME) of 0.87 mV/cm·Oe with high piezoelectric properties (g33 = 18.5 × 10 mV m N−1 and d33 = 124 pC N−1). We believe that the high room-temperature ME coupling in single-phase lead-free BT-BFO ceramics provides a possibility of developing electrically or magnetically tunable thin-film devices.

/pdf/room-temperature-magnetoelectric-coupling-in-single-phase-4e194ch9rq.pdf

Ashok Kumar

Papers

Acute pulmonary embolism: diagnosis with MR angiography.

On the synthesis and optical absorption studies of nano-size magnesium oxide powder

COVID-19-associated mucormycosis: An updated systematic review of literature.

Optical, electrical and magnetic properties of Co3O4 nanocrystallites obtained by thermal decomposition of sol–gel derived oxalates

Room-temperature magnetoelectric coupling in single-phase BaTiO3-BiFeO3 system