Enhancement of NOx adsorption performance on zeolite via a facile modification strategy.

Adsorption is a promising technology for simultaneously capturing nitrogen oxides (NOx) from flue gases and recycling NO2 as a profitable chemical, for which a robust and efficient adsorbent provides the key step for success in practical applications. This work reports the enhancement of NOx adsorption performances with less cost of desorption energy on Cu-ZSM-5 zeolites prepared by a facile and rapid (690 s) modification method, the incipient-wetness impregnation coupled with microwave drying (IM). In comparisons to H-ZSM-5, Na-ZSM-5 and conventionally liquid-phase ion-exchanged counterparts under sub-1000 ppm NOx feed concentrations and room temperature, the IM sample renders a record NOx adsorption capacity (qt,NOx) of 0.878 mmol/g from dry gas stream on zeolites, and an applicable qt,NOx of 0.1 mmol/g from wet gas stream with a proper copper loading (2.1 wt%). The temperature programmed desorption of NOx on the optimal IM sample saturated with NOx from wet gas stream exhibit primary peak temperature lower than reported Cu-ZSM-5 and significant NO2 proportion (72.6 %) in desorbed NOx. Deeper insights into advantageous NOx oxidative adsorption over the properly-loaded Cu-ZSM-5 in terms of diverse adsorbate states and competitiveness towards H2O were gained, showing IM method a promising sorbent improvement strategy for practical use.

Dynamic Adsorption/Desorption of NOx on MFI Zeolites: Effects of Relative Humidity and Si/Al Ratio.

Adsorption is a potential technology that is expected to meet NOx ultra-low emission standards and achieve the recovery of NO2. In this study, the adsorption/desorption behavior of NOx with competitive gases (e.g., H2O(g) and CO2) was studied on MFI zeolites with different Si/Al ratios and under different relative humidity (0~90% RH). Sample characterization of self-synthesizing zeolites was conducted by means of X-ray diffraction, Ar adsorption-desorption, and field emission scanning electron microscopy. The results showed that low-silica HZSM-5(35) showed the highest NOx adsorption capacity of 297.8 µmol/g (RH = 0) and 35.4 µmol/g (RH = 90%) compared to that of other adsorbents, and the efficiency loss factor of NOx adsorption capacity at 90%RH ranged from 85.3% to 88.1%. A water-resistance strategy was proposed for NOx multicomponent competitive adsorption combined with dynamic breakthrough tests and static water vapor adsorption. The presence of 14% O2 and lower adsorption temperature (25 °C) favored NOx adsorption, while higher CO2 concentrations (~10.5%) had less effect. The roll-up factor (η) was positively correlated with lower Si/Al ratios and higher H2O(g) concentrations. Unlike Silicalite-1, HZSM-5(35) exhibited an acceptable industrial desorption temperature window of NO2 (255~265 °C). This paper aims to provide a theoretical guideline for the rational selection of NOx adsorbents for practical applications.

Parenchymal hematoma and total lesion volume in combined IV/IA revascularization stroke therapy.

BACKGROUND AND PURPOSE: A positive correlation between large parenchymal hematoma (PH) volume and large CT lesion volume in subjects treated with intravenous (IV) recombinant tissue plasminogen activator (rtPA) as well as placebo controls was identified in the European Cooperative Acute Stroke Study II (ECASS II). A study was undertaken to examine the relationship between PH volume and total lesion volume (including both cerebral infarction and hemorrhage) in subjects with symptomatic parenchymal hematoma (sPH) treated with combined IV and intra-arterial (IA) rtPA in the Interventional Management of Stroke (IMS) studies. METHODS: Hematoma and lesion volumes were measured planimetrically and by the ABC/2 method in 105 subjects from IMS studies I and II following combined IV and IA rtPA treatment. PH type 1 or 2 was determined by dichotomizing at >30% of lesion volume. Hematoma and lesion volumes for both symptomatic PH1 (sPH1) and PH2 (sPH2) types were compared using both measurement methods. Both sPH types were compared for baseline NIH Stroke Score, baseline Alberta Stroke Program Early CT score and treatment revascularization score based on the planimetric volume method. RESULTS: The volume of sPH1 and sPH2 did not differ by either method of measurement. Subjects with sPH2 had a lower lesion volume compared with all PH1 (p=0.004) and sPH1 (p=0.02) by both methods. The ABC/2 method overestimated PH volume by 55±33% and lesion volume by 34±22% for sPH compared with the planimetric method. CONCLUSIONS: In IMS I and II, hemorrhages in subjects with sPH2 were similar in volume to those in subjects with sPH1 and were associated with a smaller rather than a larger total lesion volume compared with other PH in the setting of combined IV/IA therapy. The use of PH2 as a sole surrogate for sPH in studies of stroke treatment may underestimate the incidence of clinically significant hemorrhage.

The challenge of designing a treatment trial for warfarin-associated intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Warfarin-associated intracerebral hemorrhage (WICH) became more frequent in the past 2 decades. Interest in potential WICH treatment trials has grown, but the practicality of such trials has received less attention. We determined the number of patients that would be eligible for enrollment in hypothetical treatment trials for WICH using a population-based study. METHODS: We identified all patients aged 18 years or older from the Greater Cincinnati/Northern Kentucky region with nontraumatic intracerebral hemorrhage in 2005. Three hypothetical WICH treatment trial criteria sets were used to determine eligibility for enrollment, varying from relatively strict to broadly inclusive. For the hypothetical trials, we assumed the comparison of a standard therapy to an alternative therapy. Sample size calculations assumed different rates of poor outcome depending on the criteria set, various effect sizes, a 2-sided alpha of 0.05, and 80% power. Given 5 years of trial enrollment, the population base needed to enroll the required subjects was then calculated. RESULTS: Warfarin-associated intracerebral hemorrhage accounted for 54 of 286 (19%) cases of intracerebral hemorrhage within the Greater Cincinnati/Northern Kentucky region in 2005. Eligibility rates ranged from 2 of 54 WICH patients (4% of cases, strictest set) to 11 of 54 WICH patients (20% of cases, most inclusive set). Given these rates, a population base of at least 67 million persons would be required to conduct a 5-year trial for WICH with a 10% effect size using a moderately strict criteria set. CONCLUSIONS: Any planned treatment trial for WICH should anticipate significant challenges in successfully enrolling adequate numbers of patients.

Eligibility for the surgical trial in intracerebral hemorrhage II study in a population-based cohort.

INTRODUCTION: No proven treatments exist for intracerebral hemorrhage (ICH). Carefully selected patients may benefit from surgery, and an international multicenter trial is ongoing. We sought to determine how many patients in a population-based ICH cohort would have been eligible for surgery using the Surgical Trial in Intracerebral Hemorrhage II (STICH II) criteria. METHODS: We identified all patients aged > or =18 years residing in the five-county Greater Cincinnati region who were hospitalized with first-ever nontraumatic ICH in 2005. STICH II trial criteria were used to determine eligibility for treatment and reasons for exclusion. RESULTS: During 2005, 286 ICH patients were identified (103 lobar, 126 deep cerebral, 23 brainstem, 28 cerebellar, and 6 IVH). Non-lobar hemorrhages are not eligible for STICH II. Among patients with lobar hemorrhage, 22 had no exclusions. The most common (not mutually exclusive) reasons for exclusion were volume <10 cc or >100 cc (n = 46) and presence of IVH (n = 27). No significant age, gender or racial differences existed between eligible and ineligible patients with lobar ICH. Only one (4.5%) of the 22 STICH II eligible patients in our population had surgery, compared with eight of 81 (9.9%) ineligible lobar ICH patients (P = 0.43). Mortality at 180 days in STICH II eligible patients was 36% vs. 49% for ineligible lobar ICH patients (P = 0.19). CONCLUSIONS: In this population-based ICH cohort, 7.7% (22 of 286) of ICH patients would have qualified for STICH II enrollment. Other treatment options need to be explored for most ICH patients.

Casein kinase-1 isoforms differentially associate with neurofibrillary and granulovacuolar degeneration lesions.

Alzheimer's Disease (AD) is characterized by the appearance of neurofibrillary and granulovacuolar lesions in the brains of affected individuals. The former is composed of hyperphosphorylated aggregates of the microtubule-associated protein tau. The latter is poorly characterized but reacts strongly with anti-phosphoepitope antibodies indicating that it too accumulates phosphoproteins. Both lesions react strongly with antibodies directed against members of the casein kinase-1 family of phosphotransferases, a group of closely related protein kinases that frequently function in tandem with the ubiquitin modification system. To determine whether individual members of the casein kinase-1 family differentially associate with AD lesions, hippocampal sections isolated from late stage cases of AD were subjected to double-label fluorescence immunohistochemistry using a panel of selective anti-casein kinase 1 antibodies and small-molecule fluorochromes thioflavin S and thiazin red. The resultant colocalization patterns revealed that the alpha CK1 isoform strongly correlated with thioflavin S and thiazin red fluorescence, indicating that it preferentially associated with neurofibrillary lesions. In contrast, the delta isoform staining pattern was dominated by colocalization with granulovacuolar degeneration bodies. These findings suggest that granulovacuolar and neurofibrillary lesions occupy separate populations of neurons, and implicate CK1 isoforms in the generation of lesion-associated phosphoepitopes. They also suggest a nexus between the phosphorylation and ubiquitination modifications found in both lesions.

Inhibition of heat shock protein 90, a novel RET/PTC1-associated protein, increases radioiodide accumulation in thyroid cells.

RET/PTC1 is a rearranged form of the RET tyrosine kinase commonly seen in papillary thyroid carcinomas. It has been shown that RET/PTC1 decreases expression of the sodium/iodide symporter (NIS), the molecule that mediates radioiodide therapy for thyroid cancer. Using proteomic analysis, we identify hsp90 and its co-chaperone p50cdc37 as novel proteins associated with RET/PTC1. Inhibition of hsp90 function with 17-allylamino-17-demothoxygeldanamycin (17-AAG) reduces RET/PTC1 protein levels. Furthermore, 17-AAG increases radioiodide accumulation in thyroid cells, mediated in part through a protein kinase A-independent mechanism. We show that 17-AAG does not increase the total amount of NIS protein or cell surface NIS localization. Instead, 17-AAG increases radioiodide accumulation by decreasing iodide efflux. Finally, the ability of 17-AAG to increase radioiodide accumulation is not restricted to thyroid cells expressing RET/PTC1. These findings suggest that 17-AAG may be useful as a chemotherapeutic agent, not only to inhibit proliferation but also to increase the efficacy of radioiodide therapy in patients with thyroid cancer.