ATR‐FTIR spectroscopy and chemometric analysis applied to discrimination of landrace maize flours produced in southern Brazil

This work aims at discriminating flours of 26 maize landraces from southern Brazil, by using the Attenuated Total Reflection Fourier Transform Infrared (ATR‐FTIR) spectroscopy and chemometrics (principal components analysis – PCA). PCA applied to the FTIR spectra in the 3‐600 (whole spectrum) and 1650–1500 cm^?1 (fingerprint region of proteins) spectral windows clearly discriminated the Amarelão landrace. Quantitative and semi‐qualitative analysis of proteins showed a wide range among the fractions, mainly of prolamine (13.47–28.43 g Kg^?1) and glutelin (5.57–30.98 g Kg^?1) contents. Pixurum 6, Pixurum 5, and MPA1 landraces are of superior nutritional value for their albumin, globulin, and glutelin contents. PCA of the spectral dataset in the fingerprint region to carbohydrates (1200–950 and 1065–950 cm^?1) also including commercial standards of amylose and amylopectin was able in separating the Moroti genotype, which grouped with the amylopectin standard. Thus, ATR‐FTIR and PCA showed to be useful tools for the quick screening and discrimination of maize with distinct chemical composition.     

Assessment of a nanocrystal 3-D morphology by the analysis of single HAADF-HRSTEM images

This work presents the morphological characterization of CeO₂ nanocrystals by the analysis of single unfiltered high-angle annular dark-field (HAADF)-high-resolution scanning transmission electron microscopy (HRSTEM) images. The thickness of each individual atomic column is estimated by the classification of its HAADF integrated intensity using a Gaussian mixture model. The resulting thickness maps obtained from two example nanocrystals with distinct morphology were analyzed with aid of the symmetry from the CeO₂ crystallographic structure, providing an approximation for their 3-D morphology with high spatial resolution. A confidence level of ±1 atom per atomic column along the viewing direction on the thickness estimation is indicated by the use of multislice image simulation. The described characterization procedure stands out as a simple approach for retrieving morphological parameters of individual nanocrystals, such as volume and specific surface areas for different crystalline planes. The procedure is an alternative to the tilt-series tomography technique for a number of nanocrystalline systems, since its application does not require the acquisition of multiple images from the same nanocrystal along different zone axes.     

Functionalized liquid polyisoprene as a promising toughening agent for poly(lactic acid): Combining stiffness and toughness

Liquid polyisoprene rubbers (LIR) containing anhydride and carboxylic groups along their chains were successfully employed as toughening agent for poly(lactic acid) (PLA) without great influence on the stiffness of the matrix. In fact, the addition of 5% of these functionalized LIR resulted in an improvement of toughness and impact resistance of more than 2000%, whereas the reduction of the yield stress stayed in the range of 12%. No significant variation of the Young modulus was observed for the modified PLA samples. The effect of the LIR on the rheological and thermal properties of PLA was also investigated. The glass transition temperature obtained from dynamic-mechanical analysis of the PLA matrix was not affected by the addition of 10% of the liquid rubber. The scanning electron microscopy analysis revealed a significant decrease in the rubber domains for the blends containing LIR functionalized with anhydride groups. Finally, the modified PLA with anhydride-functionalized LIR was able to produce transparent film with outstanding mechanical performance than neat PLA, making this material a good option for food packaging.     

Freshwater Plants Synthesize Sulfated Polysaccharides: Heterogalactans from Water Hyacinth (Eicchornia crassipes)

Sulfated polysaccharides (SP) are found mainly in seaweeds and animals. To date, they have only been found in six plants and all inhabit saline environments. Furthermore, there are no reports of SP in freshwater or terrestrial plants. As such, this study investigated the presence of SP in freshwaters Eichhornia crassipes, Egeria densa, Egeria naja, Cabomba caroliniana, Hydrocotyle bonariensis and Nymphaea ampla. Chemical analysis identified sulfate in N. ampla, H. bonariensis and, more specifically, E. crassipes. In addition, chemical analysis, FT-IR spectroscopy, histological analysis, scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDXA), as well as agarose gel electrophoresis detected SP in all parts of E. crassipes, primarily in the root (epidermis and vascular bundle). Galactose, glucose and arabinose are the main monosaccharides found in the sulfated polysaccharides from E. crassipes. In activated partial thromboplastin time (APTT) test, to evaluate the intrinsic coagulation pathway, SP from the root and rhizome prolonged the coagulation time to double the baseline value, with 0.1 mg/mL and 0.15 mg/mL, respectively. However, SP from the leaf and petiole showed no anticoagulant activity. Eichornia SP demonstrated promising anticoagulant potential and have been selected for further studies on bioguided fractionation; isolation and characterization of pure polysaccharides from this species. Additionally in vivo experiments are needed and are already underway.     

Multimode interference tapered fiber refractive index sensors

Real-time monitoring of the fabrication process of tapering down a multimode-interference-based fiber structure is presented. The device is composed of a pure silica multimode fiber (MMF) with an initial 125?μm diameter spliced between two single-mode fibers. The process allows a thin MMF with adjustable parameters to obtain a high signal transmittance, arising from constructive interference among the guided modes at the output end of the MMF. Tapered structures with waist diameters as low as 55?μm were easily fabricated without the limitation of fragile splices or difficulty in controlling lateral fiber alignments. The sensing device is shown to be sensitive to the external environment, and a maximum sensitivity of 2946 nm/refractive index unit in the refractive index range of 1.42-1.43 was attained.     

Issues in integrating cellular networks WLANs, AND MANETs: a futuristic heterogeneous wireless network

The popularity of wireless communication systems can be seen almost everywhere in the form of cellular networks, WLANs, and WPANs. In addition, small portable devices have been increasingly equipped with multiple communication interfaces building a heterogeneous environment in terms of access technologies. The desired ubiquitous computing environment of the future has to exploit this multitude of connectivity alternatives resulting from diverse wireless communication systems and different access technologies to provide useful services with guaranteed quality to users. Many new applications require a ubiquitous computing environment capable of accessing information from different portable devices at any time and everywhere. This has motivated researchers to integrate various wireless platforms such as cellular networks, WLANs, and MANETs. Integration of different technologies with different capabilities and functionalities is an extremely complex task and involves issues at all layers of the protocol stack. This article envisions an architecture for state-of-the-art heterogeneous multihop networks, and identifies research issues that need to be addressed for successful integration of heterogeneous technologies for the next generation of wireless and mobile networks.     

The acute increases in vasomotor tone and blood pressure induced by carotid artery occlusion are modulated by platelet-activating factor (PAF) independently of nitric oxide release

The purpose of the present study was to investigate the involvement of nitric oxide (NO) in the modulatory role of platelet-activating factor (PAF, 1-O-hexadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine), a vasoactive phospholipid mediator synthesized by endothelial cells, on the vascular tone and arterial blood pressure. In pentobarbitone-anaesthetized rabbits, unloading of the carotid sinus baroreceptors by a bilateral carotid artery occlusion elicited a reflex rise in systemic vascular resistance, which was markedly potentiated by pretreating the animals with the PAF receptor antagonist WEB 2086 ([3-4-(2-chlorphenyl-)-9-methyl-6H-thieno-3,2-f-1,2,4-triazolo-4,3 -alpha-1,4 -diazepin-2-yl-(4-morpholinyl)-1-propanone]; 5 mg/kg, i.v.). In contrast, the inhibition of the biosynthesis of NO via NO synthase using N omega-nitro-L-arginine methyl ester (L-NAME) neither affected the systemic vasoconstriction induced by carotid artery occlusion nor modified the potentiating effect of WEB 2086. The haemodynamic alterations induced by L-NAME administration were corrected by continuous infusions of the directly-acting vasodilators sodium nitroprusside or diazoxide. The results of the present study confirm previous studies from our group suggesting the involvement of PAF in a negative feedback mechanism effective in the local regulation of vasomotor tone in anaesthetized rabbits, but exclude the participation of NO in this process.     

Reconstruction of total maxillectomy defects with preservation of the orbital contents

Reconstruction after total maxillectomy with preservation of the orbital contents is technically more challenging than when the maxillectomy is combined with orbital exenteration. Reconstruction of such defects should (1) provide support to the orbital contents, (2) obliterate any communication between the orbit and nasopharynx, (3) reconstruct the palatal surface, and (4) achieve facial symmetry and a good aesthetic result. We report our experience in performing reconstructive surgery on 14 patients who had a total maxillectomy and preservation of the orbital contents using nonvascularized bone grafts for reconstruction of the orbital floor and maxilla, in conjunction with a soft-tissue free flap or pedicled muscle flap. The orbital floor was reconstructed using split ribs in six cases (42.9 percent), split calvaria in six cases (42.9 percent), and iliac crest graft in two cases (14.3 percent). A myocutaneous rectus abdominis free flap was used for soft-tissue reconstruction and resurfacing of the palatal mucosa in twelve patients (85.7 percent), and a temporalis muscle transposition was used in two elderly patients (14.3 percent). One patient died 2 days after surgery. Mean follow-up and aesthetic and functional results were assessed in the remaining 13 patients a minimum of 6 months postoperatively. In 9 of these 13 patients (69.2 percent), postoperative radiotherapy was administered. No reexplorations or free flap failures were observed. One rectus flap developed partial necrosis of the skin island intraorally without affecting the final result. All patients had adequate functional vision. One patient had a mild vertical dystopia; there were no cases of enophthalmos. Ectropion was the most common undesirable result and was present in 10 of 13 cases (76.9 percent). It was graded as mild in four cases (40.0 percent), moderate in four cases (40.0 percent), and severe in the remaining two cases (20.0 percent). Speech was considered normal in six cases (46.2 percent), near normal in six cases (46.2 percent), and intelligible in one case (7.7 percent). Chewing function was considered good (soft to unrestricted diet) in all cases except for one patient who was only able to eat a pureed diet. Aesthetic results after immediate reconstruction were considered good in nine cases (69.2 percent) and fair in four cases (30.8 percent). Primary reconstruction of total maxillectomy defects with orbital content preservation remains a complex problem without a perfect solution. The combination of nonvascularized bone grafts for orbital/maxillary reconstruction with a soft-tissue free flap is a safe, reliable, and effective method of maximizing postoperative functional and aesthetic results.     

Long term growth arrest of human Tenon''s fibroblasts following single applications of beta radiation

Aortic stenosis (AS) is a major risk factor for perioperative cardiac events in patients undergoing noncardiac surgery. We previously showed that selected patients with AS who were not candidates for, or refused, aortic valve replacement could undergo noncardiac surgery with acceptable risk. We extended our previous experience over a subsequent 5-year period by retrospectively analyzing the perioperative course of all patients with severe AS (aortic valve area index < 0.5 cm2/m2 or mean gradient > 50 mm Hg), determined with Doppler echocardiography or cardiac catheterization, who underwent noncardiac surgery. Nineteen patients underwent 28 surgical procedures: 22 elective and 6 emergency. The types of these procedures were 12 orthopedic, 6 intraabdominal, 4 vascular, 4 urologic, 1 otolaryngologic, and 1 thoracic. Mean age was 75 +/- 8 years. Of the 19 patients, 16 (84%) had > or = 1 symptom: dyspnea, angina, syncope, or presyncope. Mean left ventricular ejection fraction was 61 +/- 11%. The type of anesthesia was general in 26 procedures and continuous spinal in 2. Intraarterial monitoring of blood pressure was used in 20 of the 28 surgical procedures. Intraoperative hypotensive events were treated promptly, primarily with phenylephrine. In all cases the anesthesia team was aware of the severity of the AS and integrated this into the anesthetic plan. Two patients (elective operation in 1 and emergency in 1) had complicated postoperative courses and died. There were no other intraoperative or postoperative events in any of the other patients. Although aortic valve replacement remains the primary treatment for patients with severe AS, selected patients with severe AS, who are otherwise not candidates for aortic valve replacement, can undergo noncardiac surgery with acceptable risk when appropriate intraoperative and postoperative management is used.     

A third-order bias corrected estimate in generalized linear models

Cordeiro and McCullagh (J Roy Stat Soc Ser B 53:629–643, 1991) derived a second-order bias-corrected estimate, which displays smaller bias than the classical maximum likelihood estimate in generalized linear models. This estimate, although consistent, can display pronounced bias in small to moderately large samples, as shown by Monte Carlo simulations here. In this paper, we obtain a simple matrix formula for the bias of order n ^-2 of this estimate, where n is the sample size, and define a third-order bias-corrected estimate in this class of models, which displays much smaller bias in small samples. In particular, some Monte Carlo simulations show that our new estimate can deliver substantial improvements in terms of bias and mean squared errors over the usual maximum likelihood estimate and Cordeiro and McCullagh’s estimate.