Standalone ethanol micro-reformer integrated on silicon technology for onboard production of hydrogen-rich gas.

A novel design of a silicon-based micro-reformer for onboard hydrogen generation from ethanol is presented in this work. The micro-reactor is fully fabricated with mainstream MEMS technology and consists of an active low-thermal-mass structure suspended by an insulating membrane. The suspended structure includes an embedded resistive metal heater and an array of ca. 20k vertically aligned through-silicon micro-channels per square centimetre. Each micro-channel is 500 µm in length and 50 µm in diameter allowing a unique micro-reformer configuration that presents a total surface per projected area of 16 cm(2) cm(-2) and per volume of 320 cm(2) cm(-3). The walls of the micro-channels become the active surface of the micro-reformer when coated with a homogenous thin film of Rh-Pd/CeO2 catalyst. The steam reforming of ethanol under controlled temperature conditions (using the embedded heater) and using the micro-reformer as a standalone device are evaluated. Fuel conversion rates above 94% and hydrogen selectivity values of ca. 70% were obtained when using operation conditions suitable for application in micro-solid oxide fuel cells (micro-SOFCs), i.e. 750 °C and fuel flows of 0.02 mlL min(-1) (enough to feed a one watt power source).

Combined venomics, venom gland transcriptomics, bioactivities, and antivenomics of two Bothrops jararaca populations from geographic isolated regions within the Brazilian Atlantic rainforest

Bothrops jararaca is a slender and semi-arboreal medically relevant pit viper species endemic to tropical and subtropical forests in southern Brazil, Paraguay, and northern Argentina (Misiones). Within its geographic range, it is often abundant and is an important cause of snakebite. Although no subspecies are currently recognized, geographic analyses have revealed the existence of two well-supported B. jararaca clades that diverged during the Pliocene similar to 3.8 Mya and currently display a southeastern (SE) and a southern (S) Atlantic rainforest (Mata Atlantica) distribution. The spectrum, geographic variability, and ontogenetic changes of the venom proteomes of snakes from these two B. jararaca phylogroups were investigated applying a combined venom gland transcriptomic and venomic analysis. Comparisons of the venom proteomes and transcriptomes of B. jararaca from the SE and S geographic regions revealed notable interpopulational variability that may be due to the different levels of population-specific transcriptional regulation, including, in the case of the southern population, a marked ontogenetic venom compositional change involving the upregulation of the myotoxic PLA(2) homolog, bothropstoxin-l. This population-specific marker can be used to estimate the proportion of venom from the southern population present in the B. jararaca venom pool used for the Brazilian soro antibotropico (SAB) antivenom production. On the other hand, the southeastern population-specific D49-PLA(2) molecules, BinTX-I and BinTX-II, lend support to the notion that the mainland ancestor of Bothrops insularis was originated within the same population that gave rise to the current SE B. jararaca phylogroup, and that this insular species endemic to Queimada Grande Island (Brazil) expresses a pedomorphic venom phenotype. Mirroring their compositional divergence, the two geographic B. jararaca venom pools showed distinct bioactivity profiles. However, the SAB antivenom manufactured in Vital Brazil Institute neutralized the lethal effect of both venoms to a similar extent. In addition, immobilized SAB antivenom immunocaptured most of the venom components of the venoms of both B. jararaca populations, but did not show immunoreactivity against vasoactive peptides. The Costa Rican bothropic-crotalic-lachesic (BCL) antivenom showed the same lack of reactivity against vasoactive peptides but, in addition, was less efficient immunocapturing PI- and PIII-SVMPs from the SE venom, and bothropstoxin-I, a CRISP molecule, and a D49-PLA(2) from the venom of the southern B. jararaca phylogroup. The remarkable paraspecificity exhibited by the Brazilian and the Costa Rican antivenoms indicates large immunoreactive epitope conservation across the natural history of Bothrops, a genus that has its roots in the middle Miocene. This article is part of a Special Issue entitled: Omics Evolutionary Ecolog. (C) 2015 Elsevier B.V. All rights reserved.

Recent advances in lamellarin alkaloids: isolation, synthesis and activity.

Lamellarins are a large family of marine alkaloids with potential anticancer activity that have been isolated from diverse marine organisms, mainly ascidians and sponges. All lamellarins feature a 3,4-diarylpyrrole system. Pentacyclic lamellarins, whose polyheterocyclic system has a pyrrole core, are the most active compounds. Some of these alkaloids are potently cytotoxic to various tumor cell lines. To date, Lam-D and Lam-H have been identified as lead compounds for the inhibition of topoisomerase I and HIV-1 integrase, respectively-nuclear enzymes which are over-expressed in deregulation disorders. Moreover, these compounds have been reported for their efficacy in treatment of multi-drug resistant (MDR) tumors cells without mediated drug efflux, as well as their immunomodulatory activity and selectivity towards melanoma cell lines. This article is an overview of recent literature on lamellarins, encompassing their isolation, recent synthetic strategies for their total synthesis, the preparation of their analogs, studies on their mechanisms of action, and their structure-activity relationships (SAR).

Intra-operative parathyroid hormone monitoring in patients with parathyroid cancer.

BACKGROUND: Intra-operative parathyroid hormone (PTH) monitoring (IPM) is 97% accurate in predicting postoperative eucalcemia in sporadic primary hyperparathyroidism (SPHPT). However, its usefulness in parathyroid cancer has not been demonstrated. This study reports IPM accuracy during surgical resections for parathyroid cancer. METHODS: Eight of 556 consecutive patients with SPHPT underwent parathyroidectomy using IPM and had parathyroid cancer. Operative success was defined as eucalcemia > six months and operative failure/persistent cancer as hypercalcemia within six months of parathyroidectomy. The IPM criterion for operative success was defined as a >50% decrease of peripheral PTH levels from the highest either pre-incision or pre-excision values, 10 minutes after resection. RESULTS: In eight patients, 11 operations were performed. Ten operations (91%) resulted in >50% intra-operative PTH decrease. However, in only seven (70%) of these resections, eucalcemia was achieved for >6 months with five of these seven (71%) procedures being initial en bloc resections. The remaining 3/10 (30%) operations with >50% intra-operative PTH decrease resulted in operative failures. In the last operation, intraoperative parathormone monitoring (IPM) correctly predicted operative failure. IPM sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in predicting outcome were 100, 40, 70, 100, and 75%, respectively. CONCLUSIONS: IPM with the criterion of >50% PTH drop from the highest level is less accurate in predicting operative success in parathyroid cancer when compared to SPHPT. A >50% intra-operative PTH level decrease in patients with parathyroid cancer, particularly in reoperative cases, is less predictive of complete resection. The initial recognition of this disease followed by proper resection remains essential in the treatment of parathyroid cancer.

Labeling of lymphocyte surface immunoglobulins with T4 as marker for scanning electron microscopy.

The technique originally described by Kumon et al. for the labeling of cell surface antigens under the SEM has been adapted to the study of surface immunoglobulins on human lymphocytes. Briefly, the peripheral blood lymphocytes are: 1) separated in a Ficoll Hypaque gradient, 2) rinsed with culture medium, 3) allowed to attach to plastic coverslips, 4) prefixed with 1% glutaraldehyde for 10 minutes, 5) incubated with goat anti-human immunoglobulins for 30 minutes at 24 degrees C, 6) rinsed, 7) incubated with a rabbit anti-goat IgG coupled with purified bacteriophage T4, 8) rinsed, 9) postfixed in glutaraldehyde for several hours, and 10) dried from ethanol at -75 degrees C and under 10(-2) Torr. Results from normal human lymphocytes and cells from cases of Chronic Lymphoblastic Leukemia (CLL) indicate that the method makes it possible to recognize cells with surface immunoglobulins and permits some correlation between the surface architecture of the cells and the presence of surface Ig. It also permits the study under the SEM of T-derived lymphocytes and of null cells, the unlabeled cell population, without resorting to techniques for lymphocyte subclass separation which may alter surface morphology.

The sizes of RNA subunits isolated from high and low leukaemogenic Friend virus.

The sizes of non-covalently linked RNA subunits isolated from highly leukaemogenic Friend virus derived from the plasma (PV, plasma virus) of leukaemic mice were compared to the RNA subunits isolated from low leukaemogenic Friend virus grown in tissue culture (TCV, tissue culture virus). Histograms derived from electron microscope measurements showed that about one-half of the plasma virus RNA was 1.4 to 2.5 micron in length, corresponding to a mol. wt. range from 1.8 X 10(6) to 3.2 X 10(6) and the other half less than 1.4 micron. In contrast, approx. 50% of the TCV RNA was only 0.7 to 1.6 micron in length (mol. wt. 0.9 X 10(6) to 2.0 X 10(6)) and the remainder less than 0.7 micron in length regardless of whether the virus RNA was isolated from 3, 9, 36 or 72 h cultures. The histograms suggest size classes for both TCV and PV derived RNA subunits. Data obtained from sucrose gradient sedimentation of heat-denatured FLV RNA agreed with the electron microscope length measurements. The smaller sizes of the TCV RNA subunits are hypothetically related to the limited biological activity of Friend leukaemia virus produced from leukaemic cells in culture. Comparable results were obtained using two different RNA extraction procedures. Contamination of TCV nucleic acid preparations by cellular DNA was observed even when the virions were harvested from short term cultures and purified by isopycnic sucrose gradient centrifugation. Consequently, preparations of intact virus were treated with DNase prior to sucrose gradient purification of the virions.

A quantitative comparison between in vivo-and in vitro-derived Friend leukemia virus.

The biological activities of RNA viruses derived from Friend leukemia cells in culture (TCV) were compared with those of viruses derived from the plasma (PV) of mice infected with Friend leukemia virus (FLV). The comparison was quantitatively based on the actual number of viruses used in each experiment as determined by counting under the electron microscope. Electron microscopy also provided a qualitative assessment of the structural integrity of the concentrated virus particles used in various bioassays. The data shows that the leukemogenic and spleen-focus-forming (SFF) activities of TCV, although demonstrable, are respectively 10(5) and 10(4) lower than those of PV. Moreover, TCV has 10(4) less helper activity (S+L- test) than PV. The level of reverse transcriptase activity is ten times lower in TCV than in PV which indicates that there is little correlation between polymerase activity and the other biological activities measured. The decreased biological activity of the in vitro grown virus is thought to be intrinsic to this type of virus although all extrinsic factors have not been ruled out.