Pd-Doped SSZ-13 for Low-T NOx Adsorption: an Operando FT-IR Spectroscopy Study

In this study, mechanistic aspects of NO adsorption/desorption over a home-made Pd/SSZ-13 passive NOx adsorber (PNA) catalyst are investigated. Operando FT-IR spectroscopy and microreactor experiments are performed to envisage the performance of the catalyst and the pathway involved in NO adsorption, with particular emphasis to the impact of species such as C3H6 and CO. In the absence of C3H6 and CO, NO is observed to adsorb as nitrosyls (anhydrous and hydrated) over both Pd2+ and Pd+ species, and as nitrates. 80 μmolNOx/gcat (NO/Pd molar ratio of 0.8) are adsorbed. The stability of nitrosyls is higher in comparison to the nitrates in that the former initially dehydrate and further decompose at elevated temperatures (> 300 °C) leading to the evolution of NO. The presence of CO and C3H6 negatively affects the amounts of NO adsorbed (53 and 45 μmolNOx/gcat, respectively) due to the reduction of Pd sites. CO admission to the catalyst forms a variety of carbonyl species over Pd2+, Pd+ and Pd0 sites which upon NO admission are readily displaced and NO is adsorbed as hydrated/anhydrous nitrosyls of Pdn+. The nitrosyls so formed exhibit lower thermal stability in comparison to nitrosyls observed in the absence of CO and decompose below 300 °C. The addition of C3H6 leads to the apparent formation of oxidized species like acetone, acrolein and acetates, besides propylene adsorption. The NO adsorption in the presence of C3H6 leads to the formation of Pdn+(NO)(X) complexes; upon heating the decomposition of this complexes is observed at low temperatures along with propylene and water desorption. Formation of organic nitro-compounds is also observed that decompose at higher temperatures.

A Study on Thermal and Electrical Conductivities of Ethylene-Butene Copolymer Composites with Carbon Fibers

Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.

Impact of airway management strategies on magnetic resonance image quality

BACKGROUND

Use of general anaesthesia or deep sedation during magnetic resonance imaging (MRI) studies leads to pharyngeal muscle relaxation, often resulting in snoring and subsequent vibrations with head micromotion. Given that MRI is very susceptible to motion, this causes artifacts and image quality degradation. The purpose of our study was to determine the effectiveness of different airway management techniques in overcoming micromotion-induced MRI artifacts.

METHODS

After obtaining institutional review board approval, we conducted a retrospective study on the image quality of central nervous system MRI studies in nine patients who had serial MRIs under general anaesthesia. All data were obtained from electronic records. We evaluated the following airway techniques: use of no airway device (NAD); oral, nasal, or supraglottic airway (SGA); or tracheal tube. To assess MRI quality, we developed a scoring system with a combined score ranging from 6 to 30. We used the linear mixed model to account for patient-dependent confounders.

RESULTS

We assessed 85 MRI studies from nine patients: 48 NAD, 27 SGA, four oral, four nasal, and two tracheal tube. Arithmetical mean combined scores were 21.6, 27.6, 20.3, 15.3, and 29.5, respectively. The estimated mean combined scores for the NAD and SGA cohorts were 22.0 and 27.3, respectively, showing that SGA use improved the combined score by 5.3 (P<0.0001).

CONCLUSIONS

The use of an SGA during MRI studies under general anaesthesia or deep sedation significantly improves image quality.

Influence of the PPAR-gamma2 Pro12Ala and ACE I/D polymorphisms on insulin sensitivity and training effects in healthy offspring of type 2 diabetic subjects

Aerobic endurance training improves insulin sensitivity, and is of great importance in the prevention and treatment of type 2 diabetes. The improvement in insulin sensitivity and cardiovascular function through exercise is highly variable among individuals, and is probably partly determined by genetic components. This study evaluated the peroxisome proliferation-activated receptor-gamma2 ( PPAR-gamma2) Pro12Ala polymorphism and the angiotensin converting enzyme ( ACE) I/D polymorphism with respect to any potential influence that these highly prevalent polymorphisms may impose on changes in insulin sensitivity and maximal aerobic capacity induced by exercise. Seventy-nine healthy first-degree relatives of type 2 diabetic patients were compared to a control group consisting of 54 subjects without any family history of type 2 diabetes. All subjects had a normal OGTT. The groups were comparable with respect to age (34 +/- 7 vs. 33 +/- 7 years), gender ((m/f) 43/36 vs. 30/24) and BMI (25.7 +/- 2.6 vs. 25.3 +/- 2.5 kg/m (2)); p (all) = NS. Furthermore, a subgroup of 29 offspring and 17 control subjects were engaged in a standardized training program lasting ten weeks. Insulin sensitivity (hyperinsulinemic euglycemic clamp technique) and VO (2)max (exhaustive exercise test) was assessed before and after the training period. We will demonstrate the allelic frequency of the Ala-allele of the Pro12Ala polymorphism to be lower in offspring to type 2 diabetic patients (13.3 %) compared to control subjects (21.3 %); p < 0.05. In offspring only, the Pro12Ala polymorphism of the PPAR-gamma2 gene appeared to enhance weight changes brought about by exercise (Deltaweight = - 0.3 +/- 1.4 kg vs. - 1.8 +/- 1.8 kg; p < 0.05; (Pro/Pro vs. Pro/Ala + Ala/Ala) - suggesting possible gene-environment or gene-gene interactions. The ACE I/D polymorphism was not of significant importance in determining the capability of responding to exercise in terms of improvement in insulin sensitivity or maximal aerobic capacity.

Molecular analysis reveals somatically mutated and unmutated clonal and oligoclonal B cells in T-cell-rich B-cell lymphoma

This paper describes the immunohistology and molecular genetics of 18 cases of T-cell-rich B-cell lymphoma (TCRBL). In all cases, the large B cells stained strongly for CD20, with more variable expression of CD79a, and were negative for CD30 and CD15. The majority of T cells were predominantly positive for TIA-1 and negative for CD57; a large population of histiocytes was present in all cases. Epstein-Barr virus (EBV)-coded RNA (EBER) was found in B blasts from four cases and in one case was present among the background lymphoid cells. IgH PCR products were generated in 16/18 cases and revealed clonal, oligoclonal and polyclonal PCR products in 12, two and two cases, respectively. In addition, TCRG clonal gene rearrangements were identified in two cases. TCRB gene rearrangements were polyclonal. Sequence analysis of seven cases with clonal/oligoclonal IgH gene rearrangements revealed functional sequences with predominant V(H)3 gene usage associated with various D genes and J(H)4 or J(H)6 gene segments. Four cases displayed varying degrees of replacement and silent mutations (1.8-21%), with one case exhibiting intraclonal heterogeneity; the distribution of mutations was indicative of antigen selection in three cases. The remaining three cases, including two cases with functional oligoclonal IgH rearrangements, harboured unmutated V region genes. The EBV-positive cases were associated with clonal, oligoclonal and polyclonal PCR products and with mutated and germline clonal sequences. These data indicate that TCRBL may be a heterogeneous entity associated with clonal and oligoclonal B cells derived from both germinal centre and naïve B cells.

Spontaneous regression of renal cell carcinoma: a pitfall in diagnosis of renal lesions

Two cases of renal cell carcinoma, both of which underwent extensive spontaneous regression, are reported. The first occurred in a 56 year old man, forming a well circumscribed renal cortical nodule which contained only very occasional foci of viable renal cell carcinoma with areas of hyalinisation and calcification, and with metaplastic ossification. The second lesion was removed from an 82 year old man, comprising a cystic cavity containing necrotic debris with only occasional viable foci of classical renal cell carcinoma. Spontaneous regression of renal cell carcinoma is a rare but recognised entity. These two cases emphasise the important differential diagnoses: metastatic secondary carcinomas, xanthogranulomatous pyelonephritis, and infective granulomatous conditions of the kidney. The importance of adequate tissue sampling of all renal nodules cannot be overemphasised in the processing for examination of lesions within the kidney.