Para Groups Research Articles

Intradermal Sterile Water Injection: Safe and Effective Alternative for Relief of Acute Renal Colic in the Emergency Department

BackgroundThe optimal pain relief method for acute renal colic in the emergency department remains controversial. ObjectiveWe compared the safety and efficacy of intradermal sterile water injection (ISWI) to treatment with intramuscular (IM) diclofenac, intravenous (IV) opioids, and IV paracetamol in patients with acute renal colic. MethodsThis randomized, single-blind study included 320 patients with renal colic to one of four treatment groups. The first group received ISWI at four different points around the most painful flank area. Patients in the DI, PARA, and TRAM groups received 75 mg IM diclofenac, 1 g IV paracetamol, and 100 mg IV tramadol, respectively. Pain intensity was measured using a visual analog scale (VAS) before treatment and 15, 30, and 60 min after treatment. ResultsVAS scores 15 and 30 min after treatment were significantly lower in group ISWI than in groups DI, PARA, and TRAM. However, there were no significant differences in the decrease in the pain score at baseline and at 60 min after treatment. In addition, fewer patients required rescue analgesia in group ISWI than in group TRAM. However, no significant differences were observed between group ISWI and group DI or PARA in terms of the need for rescue analgesia. Finally, there were significantly fewer adverse events in group ISWI than in groups DI and TRAM. ConclusionsISWI had similar efficacy, faster pain relief, and lower need for rescue analgesia compared with diclofenac, paracetamol, and tramadol for the management of acute renal colic. In addition, ISWI was well-tolerated and had no adverse effects.

Unexpected substituent’s effects on catalytic activity in the ring-opening polymerization of ε-CL and δ-VL catalyzed by β-pyridyl-enamino Al complexes

This contribution illustrates the significant influence of the Al-catalyzed ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) ring-opening polymerizations. A series of β-pyridyl-enamino aluminum complexes [AlLMe2] 1–6 {L = [(2-C5H4N)-C(H)C(Ph)N(Ar)], Ar = C6H5 (1), 2,6-Me2C6H3 (2), 2,6-Et2C6H3 (3), 2,6-iPr2C6H3 (4), 4-FC6H4 (5), C6F5 (6)} were synthesized and characterized by NMR spectroscopy and single-crystal X-ray diffraction. The catalytic activities the polymerization of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) correlated with the substituent’s character of the ortho and para groups on the Ar moieties of the β-pyridyl-enamino ligands. For the polymerizations of the both cyclic esters, complexes 1, 5 and 6 displayed excellent catalytic activities in the presence of the initiator benzyl alcohol, while complexes 2–4 exhibited much lower activities under the same conditions. Kinetic studies revealed that complex 5 polymerized ε-CL at a faster rate in comparison to 1 and 6, where highlighted a cumulative effect of both the electronic and steric effect on the ligands. By contrast, for the ROP of δ-VL, complex 1 was found to be more active than the catalysts 5 and 6. This unusual result was suggested the rate-determined step was the “insertion” step in ε-CL and δ-VL polymerization, the former’s insertion rate is faster than the latter’s.

Each phenyl group performs its own functions on luminescence: phenyl substituted effect in tetraphenylpyrazine

Three phenyl groups of TPP derivatives affect the luminescence process in various modes. TPPs show AIE thanks to the ortho substituted groups, while meta and para groups can modulate their luminescence in different extents.

The investigation of possible roles of central 5-HT7 receptors in antipyretic effect mechanism of paracetamol in LPS-induced hyperthermia model of mice

This study aimed to investigate the role of the 5-HT7 receptor in fever mechanisms and its possible effect on the antipyretic mechanism of paracetamol. The study consisted of eight experimental groups and one control group. Group I: healthy, II: LPS, III: LPS + PARA, IV: LPS + AGO, V: LPS + ANTA, VI: LPS + AGO + ANTA, VII: LPS + AGO + PARA, VIII: LPS + ANTA + PARA, and IX: LPS + AGO + ANTA + PARA. Rectal temperatures were measured with a rectal thermometer. At the end of the experiment, tissues were examined molecularly. Real-time PCR mRNA expression analyses were performed for the 5-HT7 receptor, IL-6, and TNF-α in hypothalamus tissue. The mean differences in rectal temperature increased in the LPS, LPS + ANTA, and LPS + AGO + ANTA groups when compared to the healthy group and decreased in the LPS + PARA, LPS + AGO, LPS + AGO + PARA, and LPS + AGO + ANTA + PARA groups when compared to the healthy group. The IL-6 and TNF-α mRNA expression increased in the LPS, LPS + ANTA, and LPS + AGO + ANTA groups when compared to the healthy group in the 2nd and 4th hours. The IL-6 and TNF-α expression decreased in the LPS + PARA, LPS + AGO, LPS + AGO + PARA, and LPS + AGO + ANTA + PARA groups when compared to the LPS group in the 2nd and 4th hours. The 5-HT7 receptor mRNA expression increased in the LPS group when compared to the healthy group in the 2nd hour. The 5-HT7 receptor mRNA expression decreased in the LPS + AGO and LPS + AGO + PARA groups when compared to the LPS group in the 2nd hour. The 5-HT7 receptor mRNA expression increased the in LPS + ANTA and LPS + ANTA + PARA groups when compared to the LPS group in the 2nd hour. The 5-HT7 receptor is a potential defense mechanism in stopping fever and the antipyretic property of paracetamol is not due to the 5-HT7 receptor.

Electronic influence of ligand substituents in the ring-opening polymerization of l-Lactide promoted by OSSO-type zirconium complexes

The zirconium complexes (OSSOCl)ZrOtBu2 (1), (OSSOBr)ZrOtBu2 (2) and (OSSOtBu)ZrOtBu2 (3) bearing OSSO-type ligands (OSSOCl-H = 1,4-dithiabutanedyl-2,2′-bis(4,6-dichlorophenol); OSSOBr-H = 1,4-dithiabutanedyl-2,2′-bis(4,6-dibromophenol); OSSOtBu-H = 1,4-dithiabutanedyl-2,2′-bis(4,6-di-tert-butyl-phenol)) were prepared and characterized. NMR spectroscopy revealed a rigid octahedral coordination geometry with a facial-facial coordination of the [OSSO] ligand to the metal complex. These compounds were active in the ring-opening polymerization of l-lactide exerting an effective control over the polymerization reaction. Activities correlated with the electron-withdrawing character of the ortho and para groups of the OSSO ligands. Density functional theory (DFT) investigations indicated that substitution with increasingly electron-withdrawing groups favors the monomer coordination and determines an earlier, more reactive transition state.

LVG analysis of amidogen radical (NH2) found in interstellar medium and in cometary material

Amidogen (NH2), a b-type asymmetric top molecule with electric dipole moment 1.82 ± 0.05 Debye, is detected in Sgr B2, in high-mass star-forming regions W31C (G10.6−0.4), W49N (G43.2−0.1), W51 (G49.5−0.4), G34.3+0.1, and in several comets. Because of two hydrogen atoms, each with nuclear spin 1/2, its rotational energy levels can be classified into ortho and para groups. We have not considered for fine structure splitting and hyper-fine structure splitting of rotational levels. For 15 rotational levels in the ground vibrational state, having energy up to 400 cm−1, for each specie, the energies of rotational levels, and Einstein A and B coefficients for radiative transitions between the levels are calculated, using accurate values of spectroscopic data. These radiative transition probabilities along with the collisional rate coefficients (obtained from a scaling law) are employed as input parameters for solving a set of statistical equilibrium equations coupled with the equations of radiative transfer for each group. Several emission lines produced by amidogen are found. For each species of NH2, we have considered some strongest emission lines along with the observed one, which may help for identification of NH2 in the interstellar medium (ISM) and in the cometary material.

Mass spectrometric detection of the Gibbs reaction for phenol analysis.

This paper describes a new method for detecting phenols, by reaction with Gibbs reagent to form indophenols, followed by mass spectrometric detection. Unlike the standard Gibbs reaction, which uses a colorometric approach, the use of mass spectrometry allows for simultaneous detection of differently substituted phenols. The procedure is demonstrated to work for a large variety of phenols without para-substitution. With para-substituted phenols, Gibbs products are still often observed, but the specific product depends on the substituent. For para groups with high electronegativity, such as methoxy or halogens, the reaction proceeds by displacement of the substituent. For groups with lower electronegativity, such as amino or alkyl groups, Gibbs products are observed that retain the substituent, indicating that the reaction occurs at the ortho or meta position. In mixtures of phenols, the relative intensities of the Gibbs products are proportional to the relative concentrations, and concentrations as low as 1μmol/L can be detected. The method is applied to the qualitative analysis of commercial liquid smoke, and it is found that hickory and mesquite flavors have significantly different phenolic composition.

14N NQR, relaxation and molecular dynamics of the explosive TNT

Multiple pulse sequences are widely used for signal enhancement in NQR detection applications. Since the various 14N NQR relaxation times, signal decay times and frequency of each NQR line have a major influence on detection sequence performance, it is important to characterise these parameters and their temperature variation, as fully as possible. In this paper we discuss such measurements for a number of the ν+ and ν− NQR lines of monoclinic and orthorhombic TNT and relate the temperature variation results to molecular dynamics. The temperature variation of the 14N spin-lattice relaxation times T1 is interpreted as due to hindered rotation of the NO2 group about the C–NO2 bond with an activation energy of 89kJmol−1 for the ortho and para groups of monoclinic TNT and 70kJmol−1 for the para group of orthorhombic TNT.

Conformational Analysis of 2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) by NMR and Molecular Modeling

2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-ones) with para and ortho-R groups on the benzene ring were prepared and studied by nuclear magnetic resonance (NMR) and molecular modeling to determine their conformational exchanges. Experimental and calculated results indicated conformational interconversions in these compounds by rotation of benzene ring and slow movement of dimedone rings, leading to intramolecular hydrogen bond length variation. The presence of one R group at the ortho position on the benzene ring modifies conformational exchange, leading to disappearance of one intramolecular hydrogen bond and superposition of diverse NMR signals. The correlation of σp values with chemical shifts, angles and atomic charges confirms that para-R groups electronic properties are involved in conformational exchange and chemical shift variance. These results will be used to study the interaction of these compounds with bio-molecules and their use as starting materials for design and synthesis of new bioactive agents.

Structure-activity relationship of 15 different Mn-salen derivatives against free radicals

Increased levels of reactive oxygen species (ROS) play a vital role in the pathogenesis of various diseases. Thus, antioxidants would play pivotal roles in the therapy of ROS-induced diseases. Regarding this fact, in the present study, we compared the relative scavenging potency and cytoprotective effects of 15 Mn-salen complexes (EUKs: eukarion antioxidant compounds), having different substituted groups, against induced free radicals (O2˙–, H2O2, ˙OH, and ABTS˙+) and protein carbonylation (PCO) in vitro as well as H2O2-induced damages and lipofuscin production in cellular systems. The results revealed that all Mn-salen complexes had considerable effects on O2˙–, H2O2, and ˙OH scavenging, relative to common antioxidants, in a concentration-dependent manner. Further, our data demonstrated that the nature and position of different substitutions on the salen ring had significant effects on scavenging activity, PCO formation, as well as suppression of cytotoxicity and apoptosis induced in cells by H2O2. Among studied complexes, EUK-15 and -123 showed the most catalase and superoxide dismutase activities, whereas their ˙OH-scavenging activities were very weak. The cytoprotective effects of the salens, mainly EUK-15 and -123, were also associated with a significant reduction in the extent of intracellular lipofuscin pigments. Evaluation of the 15 salen derivatives clearly indicated these compounds possess ROS-scavenging activity and this activity is potentiated by the presence of para and ortho alkoxy groups.

Multiparity and Childbirth Complications in Rural Women of Northeastern Nigerian Origi

This study sought to evaluate the rate of childbirth associated complications and to determine if multiparity constitutes a danger to mother and child. The cross-sectional study included women of childbearing age (15-45 years) who had attended health care facilities during pregnancies within the past two years (2009- 2011). 384 women who fall into different para groups were picked at random. Data on subjects were abstracted from their medical records. Events such as abruptio placentae, uterine rupture, hemorrhage, malpresentations and mortality were observed and their rates of occurrence in the different para groups wereanalyzed. The research findings showed that complications occurred in all groups with the highest rates occurring in grand multiparas (para 6-9) such that uterine rupture occurred in 24% of the grand multiparous group, abruptio placentae was observed 17.97%, malpresentations (20.05%) and death (4.17%). The grand multipara appears to have the highest risks of all groups of child bearing womenin the study population. Based on the high rates of childbirth complications that increased with parity, and due to poor perinatal care obtainable in the general population; multiparity is seen as dangerous and predisposes women to have childbirth complications. Thus, health workers and public health educators have the responsibility to enlighten the communities on the dangers of multiparity; husbands should value the health of their wives as a family and community asset and ought to be protected against all odds. Adequate family planning methods may be useful.

Substituent Effect on g-Tensor: Multifrequency ESR Study and DFT Calculation of Polycrystalline Phenoxyl Radicals in Diamagnetic Crystals

The substituent effect on the g-tensor of polycrystalline 2,6-di-tert-butyl phenoxyl radical derivatives diluted in diamagnetic crystals was investigated using multifrequency ESR spectroscopy and DFT calculations. It was revealed that the g-tensors of the series of phenoxyl radical derivatives essentially have an orthorhombic symmetry. For some radicals, the hyperfine-splitting tensors from the para groups were resolved. The interpretations and the assignments of the spin-Hamiltonian parameters were confirmed with computer simulations in all bands. The DFT-calculated g-tensors were consistent with the experimental g-tensors. Furthermore, the shifts Delta(g) from the free electron ge were analyzed in details as the sum of three contributions. The spin-orbit interactions were found to be the dominant factor with regard to the Delta(g). With a focus on the s-o term, thus, the relationship of the g-values and the electronic excited states was explained by visualizing the molecular orbitals of the phenoxyl radical derivatives. This study thus showed the very significant potential of the combination of a multi-frequency ESR approach and a DFT calculation to advanced ESR analysis, particularly, g-tensor analysis, even for a powder-sample radical.

The Influence of an Arduous Military Training Program on Immune Function and Upper Respiratory Tract Infection Incidence

The effects of the first 19 weeks of U.K. Parachute Regiment (PARA) training on upper respiratory tract infection (URTI) incidence and immune function (circulating leukocyte counts, lymphocyte subsets, lipopolysaccharide-stimulated neutrophil degranulation, and salivary immunoglobulin A concentrations) were investigated for 14 PARA recruits and 12 control subjects. No significant differences were reported between groups for the number or duration of URTIs, lymphocyte subsets, or salivary immunoglobulin A concentrations during training. URTI incidence was greater in the PARA group at weeks 2 and 3 (p < 0.05), coinciding with a decrease in circulating leukocyte and lymphocyte counts (p < 0.05). Neutrophil degranulation was similar in the PARA and control groups at weeks 0 and 19. Decreases in saliva flow rate occurred in the PARA group at week 15 and weeks 18 to 20 (p < 0.05). These results show a limited effect of PARA training on URTI incidence and immune function. The progressive decrease in saliva flow rate during PARA training may indicate an ensuing state of hypohydration.

A comparison between IV paracetamol and IV metamizol for postoperative analgesia after retinal surgery

ABSTRACTObjective: To assess clinical efficacy of IV paracetamol 1 g and IV metamizol 1 g on a 24‐h dosing schedule in this randomized, double-blinded, placebo-controlled study of 38 ASA physical status I–III patients undergoing retinal surgery.Research design and methods: General anaesthesia using remifentanil, propofol, and desflurane was performed for surgery. The patients were randomly allocated to three groups, receiving infusions of paracetamol 1 g/100 mL (Para Group), of metamizol 1 g/100 mL (Meta Group), or of 100 mL of saline solution as placebo control (Plac Group) 30 min before arrival in the recovery area and every 6 h up to 24 h postoperatively. All patients had unrestricted access to intravenous opioid rescue medication.Main outcome measures: The primary efficacy variables were pain scores at rest over 30 h postoperatively analysed by using repeated ANOVA measurement. Secondary efficacy variables were pain scores on coughing, also analysed by repeated ANOVA measurement.Results: Five patients in the Plac Group and one patient in the Meta Group interrupted the study protocol. Regarding pain scores at rest, Mauchly-test of sphericity was significant ( p = 0.03). For the time effects a significant result was detected ( p < 0.001). The main effect between the three treatment groups was significantly different ( p = 0.01). The Bonferroni adjusted pair wise comparisons between the Plac Group and the Para Group showed a significant difference in favour of IV paracetamol ( p = 0.024; mean difference 14.8; 95% CI 1.6–28.0), between the Plac Group and the Meta Group in favour of IV metamizol ( p = 0.025; mean difference 14.4; 95% CI 1.5–27.4), and no significant difference between the Para Group and the Meta Group ( p = 1.0; mean difference 0.4; 95% CI –12.8 to 13.6). Pain scores on coughing showed a significant different main effect between the three treatment groups ( p = 0.022). The Bonferroni adjusted pair wise comparisons between the Plac Group and the Para Group showed a significant difference in favour of IV paracetamol ( p = 0.032; mean difference 17.9; 95% CI 1.3–34.6), a difference, though not reaching statistical significance, in favour of IV metamizol between the Plac Group and the Meta Group ( p = 0.081; mean difference 15.0; 95% CI –1.4 to 31.4), and no significant difference between the Para Group and the Meta Group ( p = 1.0; mean difference 2.9; 95% CI –13.8 6 to 19.6).None of the patients experienced itching; one patient in the Meta Group developed a mild erythema. There was no statistical difference in the incidence of nausea (Plac vs. Para Group: p = 0.94, Plac vs. Meta Group: p = 0.98, Para vs Meta Group: p = 0.95) or vomiting (Plac vs. Para Group: p = 0.73, Plac vs. Meta Group: p = 0.85, Para vs Meta Group: p = 0.86) between the groups. Patients in the Plac Group experienced significantly more often sedation than patients in the Meta Group ( p = 0.049). There was a trend of higher sedation in the Plac Group than in the Para Group, which did not reach statistical significance ( p = 0.07). There was no difference in sedation between the Meta and the Para Groups ( p = 0.84).Conclusion: IV paracetamol 1 g has a similar analgesic potency as IV metamizol 1 g for postoperative analgesia after retinal surgery.

Synthesis and characterisation of castor oil-urethane acrylate oligomers

Castor oil-urethane acrylate (CVA) oligomers have been synthesised and characterised by infra-red spectroscopy (FT-IR), gel permeation chromatography(GPC) to study the relationship between the reaction kinetics and the structure of the products. It is shown that the chain terminating reaction between 2,4-toluene diisocyanate (2,4TDI) and hydroxyethylacrylate (HEA) to form isocyanatoethyl acrylate (IEA) obeys a second order mechanism, as does the chain extension reaction of IEA and castor oil (CAS). From the data of the polymerisation rate constant and the apparent activation energy, it can be seen that the different structure of CVA oligomer is dependent mainly on the different reactivities of both para and ortho NCO groups in 2,4TDI. Whereas the apparent viscosity of the CVA oligomer is related to the structure of diisocyanates. Results from the dynamic mechanical spectrum (DMS, the abstract of dynamic mechanical spectrum, a kind of detection method) indicate that the hard segment content of oligomers is then increased up to 59% (wt.). A phase-separated structure is formed and leads to the highest tensile strength (18.2MPa). When the hard segment content is increased to 67% (wt.), the dynamic modulus is reduced and the single depletion peak from DMS is exhibited at the temperature of 100.7°C.

EVOLUÇÃO TECTONOESTRATIGRÁFICA DOS SISTEMAS TRANSCORRENTES CARAJÁS E CINZEIRO, CINTURÃO ITACAIÚNAS, NA BORDA LESTE DO CRATON AMAZÔNICO, PARÁ

The Carajas-Cinzento fault system occurs within the Itacaiunas Belt, Amazonian Craton, Brazil. The regional tectonostratigraphy can be subdivided into: (1) the Basement Assemblage - orthogneisses, migmatites, and granulites (the Xingu and Pium Complexes; Plaque Suite) and a later volcano-sedimentary sequence of ironstones, quartzites, amphibolites and schists (Igarape Salobo Group). These rocks underwent intense ductile shearing and high grade metamorphism along the Itacaiunas Shear Zone (ISZ). (2) a Cover Assemblage represented by very low-grade volcanic and sedimentary rocks, rests unconformably on the basement rocks. Older clastic, volcanic and ironstone sequences (Igarape Pojuca & Grao Para Groups; ca.2.7 Ga) are overlain by a sequence of rnarine to fluvial deposits (Aguas Claras Formation). Both Cover and Basement assemblages are intruded by ca.2.5 and ca. 1.8 Ga A-type granitic plutons and basic dykes. Ali units are unconformably overlam by a localised sequence of polymitic conglomerates (Gorotire Formation). A subvertical EW mylonitic fabric developed in the Basement Assemblage rocks where it preserves widespread sinistrally transpressional kinematic indicators (oz.2.8 Ga). At least three cycles of Archaean to Proterozoic brittle-ductile strike-slip reactivation at low metamorphic grades appear to postdate the development of the ISZ, leading to the formation of the Carajas and Cinzento fault systems. The Cover Assemblage sequences were faulted down into dilational jogs formed during dextral displacements. The effects of a later episode of brittle-ductile sinistrai transpression are preserved, localised in the region of the major fault strands. Circunstantial evidences indicate further minor fault reactivation during the Phanerozoic, and the region appears to be tectonically active in the present. There is widespread evidence that the mylonitic fabrics of the ISZ controlled the orientation of later structures. Long-term fault zone weakening is common in those regions where brittle processes caused increases in fault zone permeability allowing extensive syn-tectonic fluid circulation, some of which caused gold and copper mineralization

Relationship among Redox Potentials, Proton Dissociation Constants of Pyrrolic Nitrogens, and in Vivo and in Vitro Superoxide Dismutating Activities of Manganese(III) and Iron(III) Water-Soluble Porphyrins

The log kcat values for the dismutation of O2•- by a series of monohydroxoiron(III) and aquamanganese(III) porphyrins, including ortho, meta, and para isomers of 5,10,15,20-tetrakis(N-alkylpyridiniumyl)porphyrins, were found to vary linearly with the metal-centered redox potentials (E1/2) for the M(III)/M(II) couple. Each 120 mV increase in E1/2 imparted a 10-fold increase in kcat. The observed behavior is in accord with the Marcus equation for outer-sphere electron-transfer reactions, suggesting that the same mechanism is operative for iron and manganese porphyrins. The Marcus plot enabled us to estimate the self-exchange rate constants of monohydroxoiron porphyrins to be ∼1 order of magnitude higher than those of aquamanganese porphyrins. Furthermore, E1/2 values for all of the metalloporhyrins investigated were linearly related to the acid dissociation constants (pKa3) of the pyrrolic nitrogen of the metal-free porphyrins, indicating that either E1/2, or the more readily measured pKa3, may be useful in predicting SOD activity in vitro. The most potent compounds investigated, with respect to SOD activity, are those of the ortho N-alkylpyridiniumyl series. Ortho N-alkylpyridiniumyl groups are more electron withdrawing than are the meta or para groups, thus imparting a more positive redox potential and a correspondingly higher SOD activity. Sufficiently positive potentials, or sufficiently low pKa3 values, are necessary for useful SOD activity, but so is the absence of toxicity. Despite their favorable redox potentials and SOD activities, all Fe(III) porphyrins investigated were toxic to Escherichia coli under both aerobic and anaerobic conditions and to both SOD-deficient and SOD-proficient strains. Only the ortho and meta manganese isomers of the N-alkylpyridiniumyl series (MnIIITE-2-PyP5+, MnIIITM-2-PyP5+ and MnIIITM-3-PyP5+) significantly protected SOD-deficient E. coli and allowed growth in an aerobic minimal medium. In previous work, we established that the lower toxicity of these compounds is due to diminished ability to bind to nucleic acids. The Mn(III) complexes are preferable to the Fe(III) complexes for SOD mimics possibly due to a lower tendency for axial ligation. We propose E1/2 ≥ +0.05 V vs NHE and/or pKa3 ≤ 2.0 as necessary requirements for Mn porphyrins to be considered useful SOD mimics.

Polar and Steric Substituent Effects in 5-exo-trig Cyclizations of 1-Aryl-4-penten-1-oxyl Radicals

A series of 1-aryl-substituted 4-penten-1-oxyl radicals 2 were generated from parent N-alkoxypyridinethiones 6. The intermediates 2 undergo 5-exo-trig cyclizations which are sensitive to polar and steric substituent effects. Thus, para groups in the aromatic ring alter the reactivity of radicals 2c–e by one order of magnitude without changing the stereochemical course of the 5-exo-trig reaction (cis:trans = 50:50). Substitution of the ortho methyl groups for hydrogen atoms of the phenyl group affects the cis-ring closures more than the trans reactions which lead to trans-selective alkoxyl radical reactions. Methyl groups at the terminal olefinic double bond cause a significant acceleration of K5-exo in general and of the trans reactions in particular. Thus, trans-2-isopropyl-5-phenyltetrahydrofuran (8i) was the major product in the photoreaction of pyridinethione 6i in the presence of tri-n-butyltin hydride (98% yield, cis:trans, 30:70).

The effect of lower body positive pressure on the cardiovascular response to exercise in sedentary and endurance-trained persons with paraplegia.

Exercise intolerance in persons with paraplegia (PARAS) is thought to be secondary to insufficient venous return and a subnormal cardiac output at a given oxygen uptake. However, these issues have not been resolved fully. This study utilized lower-body positive pressure (LBPP) as an intervention during arm crank exercise in PARAS in order to examine this issue. Endurance-trained (TP, n = 7) and untrained PARAS (UP, n = 10) with complete lesions between T6 and T12, and a control group consisting of sedentary able-bodied subjects (SAB, n = 10) were tested. UP and TP subjects demonstrated a diminished cardiac output (via CO2 rebreathing) during exercise compared to SAB subjects. Peak oxygen uptake (O2peak) remained unchanged for all groups following LBPP. LBPP resulted in a significant decrease in heart rate (HR) in UP and TP (P < 0.05), but not SAB subjects. LBPP produced an insignificant increase in cardiac output (Q) and stroke volume (SV). The significant decrease in HR in both PARA groups may indicate a modest hemodynamic benefit of LBPP at higher work rates where circulatory sufficiency may be most compromised. We conclude that PARAS possess a diminished cardiac output during exercise compared to the able-bodied, and LBPP fails to ameliorate significantly their exercise response irrespective of the conditioning level. These results support previous observations of a lower cardiac output during exercise in PARAS, but indicate that lower-limb blood pooling may not be a primary limitation to arm exercise in paraplegia.

Polar and Steric Substituent Effects in 5‐exo‐trig Cyclizations of 1‐Aryl‐4‐penten‐1‐oxyl Radicals

AbstractA series of 1‐aryl‐substituted 4‐penten‐1‐oxyl radicals 2 were generated from parent N‐alkoxypyridinethiones 6. The intermediates 2 undergo 5‐exo‐trig cyclizations which are sensitive to polar and steric substituent effects. Thus, para groups in the aromatic ring alter the reactivity of radicals 2c–e by one order of magnitude without changing the stereochemical course of the 5‐exo‐trig reaction (cis:trans = 50:50). Substitution of the ortho methyl groups for hydrogen atoms of the phenyl group affects the cis‐ring closures more than the trans reactions which lead to trans‐selective alkoxyl radical reactions. Methyl groups at the terminal olefinic double bond cause a significant acceleration of K5‐exo in general and of the trans reactions in particular. Thus, trans‐2‐isopropyl‐5‐phenyltetrahydrofuran (8i) was the major product in the photoreaction of pyridinethione 6i in the presence of tri‐n‐butyltin hydride (98% yield, cis:trans, 30:70).