Boosting molecular diffusion following the generalized Murray's Law by constructing hierarchical zeolites for maximized catalytic activity

Diffusion is an extremely critical step in zeolite catalysis that determines the catalytic performance, in particular for the conversion of bulky molecules. Introducing interconnected mesopores and macropores into a single microporous zeolite with the rationalized pore size at each level is an effective strategy to suppress the diffusion limitations, but remains highly challenging due to the lack of rational design principles. Herein, we demonstrate the first example of boosting molecular diffusion by constructing hierarchical Murray zeolites with a highly ordered and fully interconnected macro-meso-microporous structure on the basis of the generalized Murray's Law. Such a hierarchical Murray zeolite with a refined quantitative relationship between the pore size at each length scale exhibited 9 and 5 times higher effective diffusion rates, leading to 2.5 and 1.5 times higher catalytic performance in the bulky 1,3,5-triisopropylbenzene cracking reaction than those of microporous ZSM-5 and ZSM-5 nanocrystals, respectively. The concept of hierarchical Murray zeolites with optimized structural features and their design principles could be applied to other catalytic reactions for maximized performance.

Is Particulate Matter of Air Pollution a Vector of Covid-19 Pandemic?

The COVID-19 pandemic is a severe respiratory disease caused by the emergence of a new coronavirus, SARS-CoV-2, that very quickly spread in the human population. Fine particulate matter (PM) generated from combustion engines have been described as toxic to human health. Recent events stressed that high concentrations of PM of air pollution might favor the spread of SARS-CoV-2. Autumn approaches, air pollution will be accentuated because of weather condition. The risk of a second outbreak of Covid-19 pandemic is highly probable. Elucidating the role of PM of air pollution in the spread of the virus is thus urgent and crucial.

Scattering of ultraviolet light by avian eggshells

Eggshells are essential for the reproduction of birds since the optical properties of shells may have an impact on biological functions such as heating and UV protection, recognition by parents or camouflage. Whereas ultraviolet reflection by some bird eggshells has been recently described, its physical origin remains poorly understood. In this study, we identified a porous structure in eggshells. Using Mie scattering modelling, we found it was most likely responsible for reflectance peaks (intensities of ca. 20-50%) observed in the near-UV range. These peaks were observed by spectrophotometric measurements from eggshells of several breeds of hen, one breed of duck and one breed of quail. This optical response was interpreted in terms of the distinct visual perception of hens and humans: eggshells appearing achromatic for humans proved to be chromatic for hens. Fluorescence emission from these eggs was also characterised and attributed to the presence of protoporphyrin IX and biliverdin IXα in the shells. Electron microscopy observations revealed the presence of pores within the so-called calcified shell part (i.e., at depths between ca. 20 μm and ca. 240 μm from the eggshell's outer surface). Mercury intrusion porosimetry allowed us to quantify the pore size distribution. Simulations of the UV response of this porous structure using Mie scattering theory as well as an effective approach accounting for multiple scattering indicate that these pores are responsible for the backscattering peaks observed in the UV range, in the case of beige hen eggshells. Due to the similarities between the pore size distributions observed for beige hen eggshells and other investigated poultry eggshells, we expect Mie backscattering to be the origin of the UV response of the eggshells of many other bird species.

Screening for the Most Common Mutations of CFTR Gene among Egyptian Children with Difficult-to-Treat Asthma

Cystic fibrosis (CF) is panethnic autosomal recessive disease that affects the exocrine glands of pancreas, lungs, and intestine. It is often misdiagnosed in developing countries as difficult-to-treat asthma. We enrolled 150 Egyptian families with one or more probands who were complaining of difficult-to-treat asthma, and 112 cases were studied extensively through history taking including pedigree construction and clinical examination. In addition, spirometry and computed tomography of the chest were done in selected cases. All cases were subjected to quantitative sweat chloride test and molecular screening for the three most common mutations of cystic fibrosis transconductance regulator ( CFTR ) gene ( ΔF508 , G542X , W1282X ) using amplification refractory mutation system (ARMS) technique. Probands of difficult-to-treat asthma comprised 66 males and 46 females; their age range was 1 to 14 years. Sixty-one probands (54.5%) were carriers of one or more of the studied mutations (36 cases and 25 carriers). Six carriers of single mutations had mild respiratory symptoms and negative sweat test. The most common allele was ΔF508 , 60 alleles in 56 individuals (4 were homozygous ΔF508 / ΔF508 ) followed by W1282X in 25 individuals and G542X in 12 individuals. Allele W1282X had an increased risk of recurrent chest infection and bronchiectasis. Moreover, cases with two mutations had more severe symptoms compared with those with a single mutation. CFTR mutations and CF-related syndromes are not rare as thought in Egypt, especially among the high-risk difficult-to-treat asthma. The readily available ARMS technique is recommended for ΔF508 and/or W1282X screening on priority basis among these children.

GATA3 rs3824662 gene polymorphism as possible risk factor in a cohort of Egyptian patients with pediatric acute lymphoblastic leukemia and its prognostic impact

To investigate the possible role of GATA3 rs3824662 polymorphism as risk factor for the development of acute lymphoblastic leukemia (ALL) in a cohort of Egyptian children and to evaluate its prognostic role. Typing of GATA3 rs3824662 polymorphism was done using real-time PCR for 116 patients with ALL and 273 healthy controls. The A allele and AA genotype were significantly higher in ALL patients (p = .015 and .016, respectively) especially B-ALL (p = .014 and .01, respectively). The AA genotype was associated with shorter disease free survival (DFS) in univariate (p = .017) and multivariate cox regression analysis (p = .028), increased incidence of relapse (p = .008) and poor prognosis (p = .028) in pediatric ALL. The GATA3 rs3824662 A allele and AA genotype may be risk factors for the development of pediatric ALL especially B-ALL in the studied cohort of Egyptian patients. The AA genotype is associated with shorter DSF, increased incidence of relapse and poor prognosis in pediatric ALL.

Minimal hepatic encephalopathy in children with liver cirrhosis: diffusion-weighted MR imaging and proton MR spectroscopy of the brain

INTRODUCTION

The aim of this work was to detect minimal hepatic encephalopathy (minHE) in children with diffusion-weighted MR imaging (DWI) and proton magnetic resonance spectroscopy (1H-MRS) of the brain.

METHODS

Prospective study conducted upon 30 consecutive children (age range 6-16 years, 21 boys and 9 girls) with liver cirrhosis and 15 age- and sex-matched healthy control children. Patients with minHE (n = 17) and with no minHE (n = 13) groups and control group underwent DWI, 1H-MRS, and neuropsychological tests (NPTs). The glutamate or glutamine (Glx), myoinositol (mI), choline (Cho), and creatine (Cr) at the right ganglionic region were determined at 1H-MRS. The apparent diffusion coefficient (ADC) value and metabolic ratios of Glx/Cr, mI/Cr, and Cho/Cr were calculated.

RESULTS

There was elevated ADC value and Glx/Cr and decreased mI/CI and Ch/Cr in patients with minHE compared to no minHE and control group. There was significant difference between minHE, no minHE, and control group in the ADC value (P = 0.001 for all groups), GLx/Cr (P = 0.001 for all groups), mI/Cr (P = 0.004, 0.001, and 0.001, respectively), Ch/Cr (P = 0.001 for all groups), and full-scale IQ of NPT (P = 0.001, 0.001, and 0.143, respectively). The NPT of minHE had negative correlation with ADC value (r = -0.872, P = 0.001) and GLx/Cr (r = -0.812, P = 0.001) and positive correlation with mI/Cr (r = 0.732, P = 0.001).

CONCLUSION

DWI and 1H-MRS are imaging modalities that can detect minHE in children with liver cirrhosis and correlate well with parameters of NPT.

Investigation of the elimination of VOC mixtures over a Pd-loaded V-doped TiO2 support

Mixing butanone and toluene enhances their elimination over a Pd/5%V-TiO₂ catalyst and reduces the formation of toxic reaction by-products.

Proton MR Spectroscopy of the brain in children with neuronopathic Gaucher's disease

OBJECTIVE

To assess the clinical usefulness of proton magnetic resonance spectroscopy ((1)H-MRS) in children with neuronopathic Gaucher's disease (NGD).

METHODS

A prospective study was conducted upon 21 consecutive children with acute (n = 7) and chronic (n = 14) forms of NGD (13 boys, 8 girls; mean age 37 months) and for a control group (n = 15). All patients and controls underwent (1)H-MRS of frontal white matter. The choline/creatine (Ch/Cr) and N-acetyl aspartate (NAA)/Cr ratios were calculated. A modified severity scoring tool (m-SST) of NGD was calculated and genotyping was performed for all patients. Metabolic ratios were correlated with clinical types, m-SST and genotyping.

RESULTS

There was a significant difference in Ch/Cr (P = 0.001) between patients with NGD and the control group. Lipid peak was detected in 15 patients with NGD. Patients with acute NGD revealed higher m-SST (P = 0.001) and Ch/Cr (P = 0.001) compared with the chronic form. Patients with homozygous gene mutation (L444P/L444P) had significantly higher m-SST (P = 0.001) and Ch/Cr (P = 0.013) than those with the heterozygous gene mutation (L444P/other). The Ch/Cr was negatively correlated with m-SST (r = -0.682; P = 0.001) CONCLUSION: (1)H-MRS can be used to detect brain abnormalities in children with NGD and Ch/Cr is well correlated with m-SST and genotyping.

KEY POINTS

• Proton magnetic resonance spectroscopy offers important information in some paediatric neurological conditions. • Significantly different choline/creatine ratios were found between neuronopathic Gaucher's disease and controls. • Lipid peak helps with the diagnosis of neuronopathic Gaucher's disease. • Ch/Cr correlated with the modified severity scoring tool of Gaucher's disease.

Clinical asthma phenotypes and therapeutic responses

Asthma is a heterogeneous disease that means not all asthmatics respond to the same treatment. We hypothesize an approach to characterize asthma phenotypes based on symptomatology (shortness of breath (SOB), cough, and wheezy phenotypes) in correlation with airway inflammatory biomarkers and FEV1. We aimed to detect whether those clinical phenotypes have an impact on the response to asthma medications. Two hundred three asthmatic children were allocated randomly to receive either montelukast (5 mg at bed time) or fluticasone propionate (100 ug twice daily) for 8 consecutive weeks. Serum concentrations of IL-2Rs, ICAM-1, VCAM-1, total IgE, eosinophilic %, eosinophil cationic protein (ECP), and FEV1 were done before and after treatment to patients and once to controls. Children who have SOB were found to have higher levels of total sIgE, older age, and longer disease duration, and they responded to fluticasone alone. Cough group was found to have higher levels of eosinophilic % and sECP, younger age, shorter disease duration and responded to montelukast alone. Wheezy group showed mixed pattern and responded to both medications. Conclusion. Although there is variability in response to ICS and LTRAs, we did identify characteristics of patient that should guide the clinician in the choice of asthma medications.

Nicorandil associated anal ulcers: an estimate of incidence

INTRODUCTION

Nicorandil is a commonly prescribed antianginal medication that has been found to be associated with painful anal ulceration. The incidence of this complication is unknown. We have used the best data available to us to make an estimate of this figure in a health district with a remarkably stable population of approximately 200,000 people.

METHODS

using an electronic search of all letters generated from colorectal and gastroenterology clinics as well as endoscopy reports from January 2004 to November 2010, patients with anal ulceration who were taking nicorandil were identified. Other causes of ulceration were excluded by biopsy in the majority of cases. The central hospital and community pharmacy database was interrogated to estimate the number of patients who were prescribed nicorandil over a six-year period (2004-2010).

RESULTS

A total of 30 patients (24 men, 6 women) with a median age of 79.5 years were identified who fulfilled the criteria of: taking nicorandil; having no other identified cause for anal ulceration; and achieving eventual healing after withdrawal of nicorandil. In the six-year period an estimated mean of 1,379 patients were prescribed nicorandil each year. The mean annual incidence of anal ulcers among nicorandil users is therefore calculated to be in the region of 0.37%.

CONCLUSIONS

Anal ulceration appears to occur in approximately four in every thousand patients prescribed nicorandil each year. Prescribing physicians should explain the risk of this unpleasant complication to their patients.

Noble-metal-based catalysts supported on zeolites and macro-mesoporous metal oxide supports for the total oxidation of volatile organic compounds

The use of porous materials to eliminate volatile organic compounds (VOCs) has proven very effective towards achieving sustainability and environmental protection goals. The activity of zeolites and macro-mesoporous metal-oxide supports in the total oxidation of VOCs has been investigated, with and without noble-metal deposition, to develop highly active catalyst systems where the formation of by-products was minimal. The first catalysts employed were zeolites, which offered a good activity in the oxidation of VOCs, but were rapidly deactivated by coke deposition. The effects of the acido-basicity and ionic exchange of these zeolites showed that a higher basicity was related to exchanged ions with lower electronegativities, resulting in better catalytic performances in the elimination of VOCs. Following on from this work, noble metals were deposited onto macro-mesoporous metal-oxide supports to form mono and bimetallic catalysts. These were then tested in the oxidation of toluene to study their catalytic performance and their deactivation process. PdAu/TiO(2) and PdAu/TiO(2) -ZrO(2) 80/20 catalysts demonstrated the best activity and life span in the oxidation of toluene and propene and offered the lowest temperatures for a 50 % conversion of VOCs and the lowest coke content after catalytic testing. Different characterization techniques were employed to explain the changes occurring in catalyst structure during the oxidation of toluene and propene.

[Prevention and relief of pain induced by otolaryngological and cervicofacial surgery]

Pain after otolaryngological and cervicofacial surgery varies greatly because of the wide variety of procedures. Preventing this pain stems from the administration of paracetamol, nonsteroid anti-inflammatory drugs, nefopam, and systematic recourse to morphine when remifentanil is used. Postoperatively, the most painful surgical procedures are an indication for multimodal anesthesia and patient-controlled morphinic analgesic after titration in the postoperative postanesthesia care unit. Applying antalgic protocols, also including locoregional anesthesia, depending on the type of procedure and the patient, can improve the quality of care.

Apparent bidirectional conduction block following radiofrequency catheter ablation of typical atrial flutter

OBJECTIVE

The purpose of this study is to determine the reliability of activation sequence mapping in assessing the presence of bidirectional conduction block (BCB) in typical atrial flutter (AFL) ablation.

INTRODUCTION

Radiofrequency ablation (RFA) can cure typical AFL by creating BCB across the right atrial isthmus. Effective conduction block across this region can prevent AFL recurrence, but accurate assessment of isthmus conduction may be flawed.

METHODS

BCB was measured before and after RFA by pacing at multiple rates on both sides of the isthmus during sinus rhythm. Pacing was performed from a low lateral tricuspid annulus site (proximal to the isthmus) and a coronary sinus Os site (distal to the isthmus), while recording simultaneously from 8-10 right atrial sites bordering the isthmus (4-5 free wall sites; 4-5 septal sites) as well as from an isthmus site. After ablation reinduction of atrial flutter was attempted from both sides of the block with rapid atrial pacing after BCB was established in all patients. In some patients lines of conduction block were evident at the isthmus (using the ablation catheter to map).

RESULTS

Of 65 patients undergoing RFA of AFL, 59 had typical AFL. In all 59 patients, BCB was demonstrated at all pacing cycle lengths 30 min after RFA applications. In 6 of these 59, AFL was inducible with atrial pacing despite apparent BCB. Further RFA resulted in non inducibility in all 6 patients. In the remaining 53/59 patients, BCB was associated with noninducibility at 30 min. A total of 8 recurrences were seen during a mean 19.3 +/- 8.3 (SD) month follow-up.

CONCLUSION

Apparent BCB as determined by activation sequence mapping outside of the isthmus is an excellent marker, but, as measured, may be a misleading method of assessing the presence or absence of conduction through the isthmus. It is necessary to attempt reinduction of AFL after apparent success. Elimination of typical AFL does not preclude other AFLs.

Radiofrequency application to the posteroseptal region alters retrograde accessory pathway activation

INTRODUCTION

Radiofrequency applications to the posteroseptal region can ablate the atrioventricular accessory pathway residing in this area. In conjunction with the adjacent anatomic structures, however, ablative lesions which do not effectively ablate the accessory pathway could markedly alter retrograde atrial activation sequence and confound interpretation of further mapping of an accessory pathway.

METHODS AND RESULTS

Electrophysiologic studies, endocardial activation mapping and radiofrequency catheter ablation were undertaken in three patients with recurrent supraventricular tachycardia. Patients were initially thought to have a single posteroseptal accessory pathway; earliest ventrioatrial activation during tachycardias and during ventricular pacing was at the coronary sinus ostium, but initial radiofrequency applications were unsuccessful to ablate the pathway. After initial radiofrequency applications to the posteroseptal region, the earliest retrograde atrial activation changed to the right atrial free wall in two patients. Additional radiofrequency application to the posteroseptal area was able to ablate the single posteroseptal accessory pathway in one patient. Radiofrequency application to the right atrial free wall was required to stop tachycardia initiation in other patient. The third patient was suspected of having a slow-slow atrioventricular nodal reentry tachycardia. Radiofrequency application to the posteroseptal area changed the earliest retrograde atrial activation to the distal coronary sinus recording site, mimicking an accessory pathway at the left atrial free wall. Radiofrequency application to the anteroseptum was able to ablate the concealed accessory pathway.

CONCLUSION

Radiofrequency applications to the posteroseptal region can markedly alter retrograde atrial activation, thereby confounding further mapping of the accessory pathway.

Species variation in the site and mechanism of the neuromuscular effects of diadonium in rodents

The unusually wide, 80-fold species variation observed by others (1,2) in the neuromuscular (NM) potency of diadonium, a nondepolarizing muscle relaxant (MR), between cat and man suggested that the site and mechanism of its NM effect may vary in different species. To obtain information on this question, the NM potency of diadonium and the reversibility of its NM effect by neostigmine and/or 4-aminopyridine (4AP) was investigated on the in vitro phrenic nerve--hemidiaphragm preparations of rats, mice and guinea pigs. The concentration of diadonium that caused 90% NM block (IC90) was much greater in guinea pigs, 1.74 +/- 0.02 and 1.28 +/- 0.01 mu, when the preparations were stimulated with single stimuli at 0.1 Hz or with 0.1 s trains of 50 Hz tetani every 10 s, respectively, than in rats (IC90 = 62.4 +/- 0.89 and 52.1 +/- 1.00 microM) or mice (IC90 = 51.9 +/- 0.98 and 44.4 +/- 0.22 microM). In guinea pigs, the NM blocking effect of diadonium could be antagonized by neostigmine. This indicates that in this species the NM blocking effect of diadonium is primarily caused by inhibition of the interaction of acetylcholine (ACh), released by the nerve impulse, with the cholinergic receptors (cholinoceptors) of the postjunctional membrane (p.j.m.). By contrast, in rats and mice diadonium was not antagonized by neostigmine but was reversed by 4-aminopyridine. This suggests that in these species, in contrast to other nondepolarizing MR, diadonium does not inhibit NM transmission postsynaptically, but by inhibiting the positive nicotinic feedback mechanism of mobilization of ACh from reserve depots to release sites, causes a presynaptic NM block.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects of high-frequency jet ventilation in patients with and without circulatory shock

Nineteen critically ill patients with acute respiratory failure were studied to compare the hemodynamic effects of continuous positive-pressure ventilation (CPPV) and high-frequency jet ventilation (HFJV) at comparable levels of alveolar ventilation. Patients were divided into three groups: Group 1 included seven patients without circulatory shock in whom mean airway pressure (Paw) was slightly higher during CPPV than during HFJV (17.3 +/- 3.0 vs. 13.0 +/- 2.9 mmHg); Group 2 included six patients without circulatory shock in whom HFJV and CPPV were compared at the same level of Paw (19.2 +/- 5.0 mmHg); Group 3 included seven patients with circulatory shock in whom HFJV and CPPV were compared at the same level of Paw (16.0 +/- 3.9 mmHg). The following respiratory frequencies were used in HFJV: Group 1, 200 +/- 76 beats/min; Group 2, 238 +/- 103 beats/min; Group 3, 286 +/- 149 beats/min. In all patients comparable levels of PaCO2 were obtained with CPPV and HFJV. In Group 1 patients, mean arterial pressure, cardiac index, and stroke index were significantly higher during HFJV. In Group 2 patients, no significant difference was found between HFJV and CPPV. In Group 3 patients, the following hemodynamic variables were significantly higher during HFJV: mean arterial pressure (71 +/- 24 vs. 84 +/- 23 mmHg), cardiac index (3.6 +/- 1 vs. 4.1 +/- 1.41 X min-1 X m-2), and oxygen delivery (403 +/- 93 vs. 471 +/- 124 ml X min-1 X m-2).(ABSTRACT TRUNCATED AT 250 WORDS)

[Acute postoperative pulmonary edema in the coronary patient: effects of myocardial ischemia]

In order to evaluate the incidence of myocardial ischaemia in patients who developed acute pulmonary oedema during the immediate post-operative period, continuous monitoring of the electrocardiogram by the Holter method was used in 200 consecutive patients with coronary artery disease. Fourteen of these patients exhibited ST segment depression during the post-operative period and 13 during surgery. Nine patients developed acute pulmonary oedema immediately after the operation and in 7 cases the oedema was preceded by myocardial ischaemia. A continuous nitroglycerin infusion brought about regression of the pulmonary oedema in 8 cases. One patient died despite treatment. These findings underline the part played by myocardial ischaemia in the pathogenesis of acute post-operative pulmonary oedema in patients with coronary artery disease.

Bilirubin and alkaline phosphatase clearance from blood-plasma by perfusion through activated carbon

A prepared solution, human urine, bile, and stored blood were perfused through a carbon column. Urea, bilirubin, and calcium were adsorbed in particular, and the fluids became progressively more alkaline. Ammonia was not absorbed. In 6 dogs with obstructive jaundice, a haemoperfusion through a similar carbon column was carried out. A simple technique avoiding serious damage to the blood-cell elements is described. A reduction of the serum bilirubin and of the serum alkaline phosphatase occurred after haemoperfusion.