“
“Experiments on adult zebrafish (Danio rerio) were conducted to assess histopathological effects induced on gill, muscle, and gonadal tissues after waterborne uranium exposure. Although histopathology is often employed as a tool for the detection and assessment of xenobiotic-mediated effects in aquatic organisms, few studies have been dedicated to the investigation of histopathological click here consequences of uranium exposure in fish. Results showed that gill tissue architecture was markedly disrupted. Major symptoms were alterations of the secondary lamellae epithelium (from extensive oedema to desquamation),

hyperplasia of chloride cells, and breakdown of the pillar cell system. Muscle histology was also affected. Degeneration and disorganization of myofibrillar sarcomeric pattern as well as abnormal localization of mitochondria within muscle and altered endomysial sheaths were observed. Morphological alterations of spermatozoa within the gonadal tissue were also noticed. This study demonstrated that uranium exposure induced a variety

of histological impairments in fish, supporting environmental concerns when uranium contaminates aquatic systems. (C) 2010 Elsevier B.V. All rights reserved.”
“Purpose To assess ocular and systemic factors associated with diabetes mellitus in the adult population in rural and urban China.\n\nMethods Selleck Ricolinostat The Beijing Eye Study 2006, a population-based, cross-sectional cohort study, included 3251 subjects aged 45 years and more (participation rate: 73.2%). Blood samples were available for 2960 (91.0%) subjects. Diabetes mellitus was defined by a fasting plasma glucose concentration >= 7.0 mmol/l or by a self-reported history diagnosis of diabetes.\n\nResults Diabetes mellitus was found in 381 (12.9%) subjects. In binary regression analysis, the presence of diabetes mellitus was significantly associated with body mass index, systolic blood pressure, triglyceride concentrations, intraocular pressure, cylindrical refractive dioptre, presence of arteriolar sheathing, rural vs urban region, lower best-corrected visual acuity, lower

highdensity lipoprotein level, and lower diastolic blood AG-120 research buy pressure. It was not statistically associated with age, presence of cataract (nuclear, cortical, or subcapsular), size of the optic disc, neuroretinal rim, a zone and beta zone of peripapillary atrophy, retinal artery and vein diameters, arteriovenous nicking, focal or general narrowing, refractive error, prevalence of glaucoma, and early or late stage of age-related macular degeneration.\n\nConclusions In a population-based setting, diabetes mellitus was not associated with optic disc, rim and peripapillary atrophy measurements, retinal vessel diameters, arteriovenous nicking, focal or general retinal artery narrowing, and prevalence of age-related macular degeneration.

One enzyme 3-MA in vivo of this superfamily, the industrially important (for beta-lactam antibiotic synthesis) AXE/CAH (acetyl xylan esterase/cephalosporin acetyl hydrolase) from the biotechnologically valuable organism Bacillus pumilus, exhibits low sensitivity to the organophosphate paraoxon (diethyl-p-nitrophenyl phosphate, also called paraoxon-ethyl),

reflected in a high K-i for it (similar to 5 mM) and in a slow formation (t(1/2) similar to 1 min) of the covalent adduct of the enzyme and for DEP (E-DEP, enzyme-diethyl phosphate, i.e. enzyme-paraoxon). The crystal structure of the E-DEP complex determined at 2.7 angstrom resolution (1 angstrom = 0.1 nm) reveals strain in the active Seri(181)-bound organophosphate as a likely cause for the limited paraoxon sensitivity. The strain results from active-site-size limitation imposed by bulky conserved aromatic residues that may exclude as substrates esters having acyl groups larger than acetate. Interestingly, in the doughnut-like MLN4924 supplier homohexamer of the enzyme, the six active sites

are confined within a central chamber formed between two 60 degrees-staggered trimers. The exclusive access to this chamber through a hole around the three-fold axis possibly limits the size of the xylan natural substrates. The enzyme provides a rigid scaffold for catalysis, as reflected in the lack of movement associated with paraoxon adduct formation, as revealed by comparing this adduct structure with that also determined in the present study at 1.9 angstrom resolution for the paraoxon-free enzyme.”
“Skeletal tissue has the capability to adapt its mass and structure in response to mechanical stress. However, selleck chemical the molecular mechanism of bone and cartilage

to respond to mechanical stress are not fully understood. A label-free quantitative proteome approach was used for the first time to obtain a global perspective of the response of skeletal tissue to mechanical stress. Label-free quantitative analysis of 1D-PAGE-LC/MS/MS based proteomics was applied to identify differentially expressed proteins. Differential expression analysis in the experimental groups and control group showed significant changes for 248 proteins including proteins related to proliferation, differentiation, regulation of signal transduction and energy metabolic pathways. Fluorescence labeling by incorporation of alizarin/calcein in newly formed bone minerals qualitatively demonstrated new bone formation. Skeletal tissues under mechanical load evoked marked new bone formation in comparison with the control group. Bone material apposition was evident. Our data suggest that 39 proteins were assigned a role in anabolic process. Comparisons of anabolic versus catabolic features of the proteomes show that 42 proteins were related to catabolic.

Oral anticoagulation

(OAC) is far more effective than antiplatelet agents at reducing stroke risk in patients with AF. Therefore, increasing numbers of elderly patients are candidates for, and could benefit from, the use of anticoagulants. However, elderly people with AF are less likely to receive OAC therapy. This is mainly due to concerns about a higher risk of OAC-associated hemorrhage in the elderly population. Until recently, older patients were under-represented in randomized controlled trials of OAC versus placebo or antiplatelet therapy, and therefore the evidence base for the value of OAC in the elderly population was not known. However, analyses of the available trial data indicate that the expected net clinical DNA Damage inhibitor benefit of warfarin therapy is highest among patients with the highest untreated risk for stroke, which includes the oldest age category. An important selleck chemicals caveat with warfarin treatment is maintenance of a therapeutic international normalized ratio, regardless of the age of the patient, where time in therapeutic range should be >= 65%. Therefore, age alone should not prevent prescription of OAC in elderly patients, given an appropriate stroke and bleeding

risk stratification. (J Am Coll Cardiol 2010; 56:827-37) (C) 2010 by the American College of Cardiology Foundation”
“Banana bunchy top virus (BBTV) is the most destructive pathogenic virus of banana plants worldwide. The virus is transmitted in a circulative non-propagative manner by the banana aphid, Pentalonia nigronervosa Coquerel.

In this work, we examined the localization, accumulation, and transmission efficiency of BBTV in four laboratory-established lineages Selleckchem A-1210477 of Pentalonia aphids derived from four different host plants: taro (Colocasia esculenta), heliconia (Heliconia spp.), red ginger (Alpinia purpurata), and banana (Musa sp.). Mitochondrial sequencing identified three and one lineages as Pentalonia caladii van der Goot, a recently proposed species, and P. nigronervosa, respectively. Microsatellite analysis separated the aphid lineages into four distinct genotypes. The transmission of BBTV was tested using leaf disk and whole-plant assays, both of which showed that all four lineages are competent vectors of BBTV, although the P. caladii from heliconia transmitted BBTV to the leaf disks at a significantly lower rate than did P. nigronervosa. The concentration of BBTV in dissected guts, haemolymph, and salivary glands was quantified by real-time PCR. The BBTV titer reached similar concentrations in the guts, haemolymph, and salivary glands of aphids from all four lineages tested. Furthermore, immunofluorescence assays showed that BBTV antigens localized to the anterior midguts and the principal salivary glands, demonstrating a similar pattern of translocations across the four lineages. The results reported in this study showed for the first time that P. caladii is a competent vector of BBTV.

Most parents and children were satisfied with their pain management.”
“Technology evaluation has been increasingly important because of the pressing needs of new product introduction in a competitive global market. To select the most appropriate

technology, a firm needs to have a robust technology evaluation framework to evaluate several technology candidates based on multiple criteria and evaluated by multiple experts. Thus, this paper presents an integrated model for evaluating various technologies for New Product Development Selleck GS 1101 (NPD). A network that takes into account the benefits, opportunities, costs, and risks (BOCR) aspects of different technologies is constructed first, and interpretive structural modeling (ISM) is applied next to determine the interrelationships among the factors. Finally, fuzzy analytic network process (FANP) is used to facilitate the evaluation process of decision makers under an uncertain environment with interrelated factors. The proposed model is applied in a flat panel manufacturer in selecting the most suitable panel technology.”
“This retrospective

study compared adverse-event rates in patients with chronic lymphocytic leukemia (CLL) or non-Hodgkin lymphoma (NHL), with and without renal impairment, receiving bendamustine alone or with rituximab. Patients (n = 940) were stratified into a renally impaired group (creatinine clearance [CrCL] smaller than 40 mL/min) and two comparator groups (CrCL bigger than = 40 mL/min and Histone Methyltransf inhibitor CrCL bigger than = 60 mL/min). Renally click here impaired patients with NHL had a significantly greater incidence of grade 3-4 thrombocytopenia compared with the CrCL bigger than = 60 mL/min group (hazard ratio [HR], 2.57; p = 0.025). For CLL and NHL together, grade 3-4 increased blood urea nitrogen was significantly higher in the renally impaired group than in the

CrCL bigger than = 40 mL/min (HR, 2.36; p = 0.02) and CrCL bigger than = 60 mL/min (HR, 4.46; p = 0.001) groups. Based on these results, monitoring blood counts (including platelets) and renal function would be prudent in the management of patients with renal dysfunction and NHL or CLL who receive bendamustine-based regimens.”
“Several C-1-imino conjugates of d-galactose, d-lactose and d-ribose, where the nitrogen center was substituted by the salicylidene or naphthylidene, were synthesized and characterized. Similar C-2-imino conjugates of d-glucose have also been synthesized. All the glyco-imino-conjugates, which are transition state analogues, exhibited 100% inhibition of the activity towards glycosidases extracted from soybean and jack bean meal. Among these, a galactosyl-napthyl-imine-conjugate (1c) showed 50% inhibition of the activity of pure alpha-mannosidase from jack bean at 22 +/- 2.5 mu M, and a ribosyl-naphthyl-imine-conjugate (3c) showed at 31 +/- 5.5 mu M and hence these conjugates are potent inhibitors of glycosidases.

A surgical specimen of HCC was immunostained with an Fz2 antibody. A 3 -(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt assay was performed on HCC cell lines, including HLF and Hep3B, 72 h after the transfection of the short hairpin (sh)RNA of Fz2 (shRNA-Fz2). RNA was isolated from the Hep3B and HLF cells 48 h after transfection and subjected to quantitative PCR. All cell lines had elevated levels of Fz2 compared with those in an adult liver. The highest and lowest expression AZD3965 in vivo levels of Fz2 were 246.9 +/- 15.7 in the HLF cells and 5.8 +/- 1.4 in the Hep3B cells, respectively.

Fz2 was expressed in the tumorous HCC tissue, but not in the surrounding non-tumorous tissue. Cell proliferation was suppressed to 28.6 +/- 6.4% in the HLF cells and to 29.8 +/- 4.3% in the Hep3B cells at 100 ng shRNA-Fz2 per well. Levels of cyclin D1 expression decreased to 65.2 +/- buy Compound C 5.9% in the HLF cells and to 60.8 +/- 14.6% in the Hep3B cells at 2.5 mu g per well. In conclusion, Fz2 was upregulated in the HCC cells. shRNA-Fz2 suppressed the proliferation of the Hep3B and HLF cell, decreasing Fz2 expression. As it was not expressed in the surrounding non-tumorous tissue, Fz2 may be an ideal molecular therapeutic target for HCC.”
“Immune cell entry into the virally infected CNS is vital for promoting viral clearance yet

may contribute to neuropathology if not rigorously regulated. We previously showed BIIB057 datasheet that signaling through IL-1R1 is critical for effector T cell reactivation and virologic control within the CNS during murine West Nile virus (WNV) encephalitis. WNV-infected IL-1R1(-/-) mice also display increased parenchymal penetration of CD8(+) T cells despite lack of CD4-mediated full activation,

suggesting dysregulation of molecular components of CNS immune privilege. In this study, we show that IL-1 signaling regulates the CNS entry of virus-specific lymphocytes, promoting protective immune responses to CNS viral infections that limit immunopathology. Analysis of blood-brain barrier function in the WNV-infected IL-1R1(-/-) mice revealed no alterations in permeability. However, parenchymal proinflammatory chemokine expression, including CCL2, CCL5, and CXCL10, was significantly upregulated, whereas microvasculature CXCL12 expression was significantly decreased in the absence of IL-1 signaling. We show that during WNV infection, CD11b(+)D45(hi) infiltrating cells (macrophages) are the primary producers of IL-1 beta within the CNS and, through the use of an in vitro blood-brain barrier model, that IL-1 beta promotes CXCR4-mediated T cell adhesion to brain microvasculature endothelial cells. Of interest, IFN gamma(+) and CD69(+) WNV-primed T cells were able to overcome CXCL12-mediated adhesion via downregulation of CXCR4.

(C) 2008 Elsevier Ireland Ltd. All fights reserved.”
“Aryl-2,4-dichloro-5-formylimidazoles by a successive treatment with hydroxylamine and thionyl chloride were converted into 1-aryl-2,4-dichloroimidazole-5-carbonitriles which by the action of sodium azide and tin(II) chloride were transformed into 2-amino-1-aryl-4-chloroimidazole-5-carbonitriles.

The consecutive reactions HKI-272 nmr of 2-azido-1-aryl-4-chloro-5-formylimidazoles with N-bromosuccinimide, methanol, or amides led to the formation of methyl esters and amides of 2-azido-1-aryl-4-chloroimidazole-5-carboxylic acids. The reduction of the latter with tin(II) chloride resulted in the corresponding derivatives of 2-amino-1-aryl-4-chloroimidazole-5-carboxylic acids, and the reduction of 2-azido-1-aryl-4-chloroimidazole-5-carboxylic BI-2536 acids was accompanied with decarboxylation and yielded 2-amino-1-aryl-4-chloroimidazoles.”
“Glutathione

S-transferase (GST) inhibition-directed fractionations on the ethanolic extract of Artocarpus nobilis of Sri Lankan origin yielded four known triterpenoids, cyclolaudenyl acetate (1), lupeol acetate (2), beta-amyrine acetate (3), and zizphursolic acid (4), along with five known flavonoids, artonins E (5), artobiloxanthone (6) artoindonesianin U (7), cyclocommunol (8) and multiflorins A (9). Our recent chemical studies on the methanolic extract of Matricaria chamomilla, collected from Manitoba, afforded one new compound, matriisobenzofuran (10), and six known natural products, fraxidin (11), scopoletin (12), apigenin (13), apigenin 7-O-beta-glucopyranoside (14), palmatoside A (15)

and p-hydroxyacetophenone (16). Compounds 1-16 were identified with the aid of extensive NMR VX-689 and MS spectral data. Compounds 1-16 exhibited a wide range of GST inhibition activity. Compounds 5-9 exhibited significant anti-oxidant activity in DPPH free radical scavenging assay. Compounds 10 and 11 were also moderately active in anti-leishmanial assay. (C) 2010 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.”
“This article presents a reconstruction of the development of the ombrotrophic Gazwa peatland based on a high-resolution macrofossil analysis and AMS dating. Successional changes in the plant assemblages dominated by Sphagnum were influenced mainly by climate changes. Local fires occurred in the peatland, but did not have a substantial impact on the Sphagnum succession. The disappearance of the first stage of the ombrotrophic peatland, which was dominated by Sphagnum magellanicum and Sphagnum angustifolium, resulted from a decrease in the water level that was also recorded at a number of sites in Europe in approximately 3750 BC. The development of Sphagnum fuscum/rubellum assemblages in approximately 350 BC corresponds with a climate cooling that resulted from low solar activity. The re-appearance of Sphagnum magellanicum in approximately AD 1650 corresponds with the Maunder Minimum of the Little Ice Age.

sAPP alpha shedding www.selleckchem.com/ferroptosis.html is inhibited by P2X7R antagonists or knockdown

of P2X7R with specific small interfering RNA (siRNA) and is not observed in neural cells from P2X7R-deficient mice. P2X7R-dependent APP-cleavage is independent of extracellular calcium and strongly inhibited by hydroxamate-based metalloprotease inhibitors, TAPI-2 and GM6001. However, knockdown of a disintegrin and metalloproteinase-9 (ADAM9), ADAM10 and ADAM17 by specific siRNA, known to have alpha-secretase activity, does not block the P2X7R-dependent non-amyloidogenic pathway. Using several specific pharmacological inhibitors, we demonstrate that the mitogen-activated protein kinase modules Erk1/2 and JNK are involved in P2X7R-dependent alpha-secretase activity. Our study suggests that P2X7R, which is expressed in hippocampal neurons and glial cells, is a potential therapeutic target in AD.”
“Recent studies showed that most cells have receptors and enzymes responsible for metabolism of vitamin D. Several diseases have been linked to vitamin D deficiency, such as hypertension, diabetes, depression, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and chronic pain syndromes

such as fibromyalgia. The association between fibromyalgia and vitamin D deficiency is very controversial in the literature with conflicting studies and methodological problems, which leads to more questions Stem Cell Compound Library mw than answers. The purpose of this article is to raise questions about the association of hypovitaminosis D with fibromyalgia considering causal relationships, treatment, and pathophysiological explanations.”
“Objective: To study the association between the epsilon 4 allele of apolipoprotein E (APOE epsilon 4) and delirium in a stroke population. Methods: 527 consecutive stroke patients were screened for delirium during the first week of admission with the confusion assessment method. In three hundred fifty-three patients genomic DNA isolation was available. Results: The incidence of delirium after stroke in the 353 patients was 11.3%. There was no association between APOE epsilon 4 and delirium. Even after adjustment for IQCODE,

stroke localization, stroke subtype, stroke severity, infection, and brain atrophy no association was found (odds ratio: 0.9; SC79 manufacturer 95% confidence interval: 0.4-2.1). Delirium did not last longer in patients with an APOE epsilon 4 allele compared to patients without an APOE epsilon 4 allele (median: 5.6 days [range: 1-21] versus median: 4.6 days [range: 1-15], p = 0.5). Conclusion: There was no association between the presence of an APOE epsilon 4 allele and the occurrence of delirium in the acute phase after stroke.”
“Objective: To compare the clinical characteristics and symptom severity of children with obsessive disorder (OCD) plus autism spectrum disorders (ASD) with those of children with OCD plus Tourette’s syndrome (TS) or OCD alone.

\n\nResults: PF OA was present in 12/75 knees (16%). Of 94 patients 22 (23%) have had their ACL reconstructed during follow-up. Meniscal injury and ACL reconstruction had occurred more often in knees with PF OA than in knees without PF OA (P = 0.004 and P = 0.002, respectively). Seven of 15 ACL reconstructed knees showed radiographic PF OA at follow-up. Knees with PF OA had more extension and flexion

deficit than knees without PF OA. Subjects with PF OA maintained a higher activity https://www.selleckchem.com/products/Belinostat.html level from injury to follow-up, but did not differ significantly from those without PF OA regarding patient-relevant symptoms and knee function. However, there was a trend for worse outcome in subjects with PF OA.\n\nConclusion: We found a relatively low prevalence of mild PF OA after ACL injury treated non-operatively,

and it had limited impact on knee symptoms and patient-relevant knee function. At follow-up PF OA was associated with higher activity level, meniscal injury, extension and flexion deficit, and ACL reconstruction. (c) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.”
“Spinal subarachnoid hematoma (SSH) is a rare condition, more commonly occurring after lumbar puncture for diagnostic or anesthesiological procedures. It has also been observed after traumatic events, in patients under anticoagulation therapy or in case of arteriovenous malformation rupture. In a very small selleck screening library number of cases no causative agent can be identified and a diagnosis of spontaneous SSH is established. The lumbar and thoracic spine are the most frequently involved segments and only seven cases of cervical spine SSH have been described until now. Differential diagnosis between subdural and subaraclmoid hematoma is complex because the common neuroradiological GDC-0068 cost investigations, including a magnetic resonance imaging (MRI), are not enough sensitive to exactly define clot location. Actually, confirmation of the subarachnoid location of bleeding

is obtained at surgery, which is necessary to resolve the fast and sometimes dramatic evolution of clinical symptoms. Nonetheless, there are occasional reports on successful conservative treatment of these lesions. We present a peculiar case of subarachnoid hematoma of the craniocervical junction, developing after the rupture of a right temporal lobe contusion within the adjacent arachnoidal spaces and the following clot migration along the right lateral aspect of the foramen magnum and the upper cervical spine, causing severe neurological impairment. After surgical removal of the hematoma, significant symptom improvement was observed.”
“Purpose of review The true clinical significance of variant histology is controversial and diagnosis is challenging, especially in the setting of nonmuscle invasive (NMI) disease. If the presence of variant architecture in NMI identifies a high-risk population with a worse prognosis and better suited for early aggressive intervention (i.e.

2 to 40 mu g L-1 (r(2) > 0.99), and detection limits were in the range from 0.062 to 0.21 mu g L-1. Real water samples were used for validating the method and recoveries of spiked samples were over the range from 82.0 to 100%. The results indicated that TiO2 nanotubes repesented an attractive alternative sorbent for the enrichment and trace analysis of such pollutants.”
“Acute cytotoxicity (neutral

red assay), AhR-mediated toxicity (CYP P450 1A induction potential EROD assay) and concentrations of PAHs were recorded in RTL-W1 cells to assess the ecotoxicological click here potential of sediments from reservoirs along the Tiete River and the Pinheiros River (Brazil). Almost all sediments tested induced cytotoxicity and stimulated cytochrome P450-associated EROD activity. Toxicity increases from Tiete River spring to Sao Paulo city region and decreases towards downstream. A closer analysis of chemical measurements of PAHs and results from bioassay revealed that the PAHs analyzed could not explain more than 7% of the EROD-inducing potencies.

Results P5091 Ubiquitin inhibitor confirm that most of the toxicity is due to the discharges of the metropolitan area of Sao Paulo. Moreover, they indicate additional sources of pollutants along the river course, which contribute to the degradation of each reservoir. (C) 2009 Elsevier Inc. All rights reserved.”
“To systematically review the literature about maternal and Vadimezan cost neonatal outcomes following induction of labor (IOL) and spontaneous labor (SL) in women with previous cesarean section (PCS). PubMed, Medline, EMBASE,

Cochrane library searches; January 2000-February 2013. Inclusion criteria: women attempting labor after PCS, singleton term pregnancies. Women undergoing IOL were compared with women in SL. Method for induction, mode of delivery, uterine rupture/dehiscence, post-partum hemorrhage, emergency hysterectomy and any maternal or neonatal morbidity and mortality were analyzed. MOOSE guidelines were followed. Interstudies heterogeneity was tested. A random effect model was generated if heterogeneity was bigger than 25 %. Pooled odds ratio with 95 % confidence interval (OR, 95 % CI) were calculated. Eight articles included 4,038 women with IOL (23.2 %) and 13,374 women with SL (76.8 %). IOL was associated with a lower incidence of vaginal delivery (OR 0.66; 95 % CI 0.55-0.80) and higher rates of cesarean section (OR 1.52; 95 % CI 1.26-1.83), uterine rupture/dehiscence (OR 1.62; 95 % CI 1.13-2.31), and post-partum hemorrhage (OR 1.57; 95 % CI 1.20-2.04), although hysterectomy was similar between the two groups (OR 2.60; 95 % CI 0.52-13.1). Neonatal morbidity was similar after IOL or SL (OR 1.13; 95 % CI 0.75-1.69). Induction of labor increases the risk of uterine rupture/dehiscence and of repeat cesarean section.

The close relationship between HOMO-LUMO separations, symmetry considerations, and reactivity of the open shell in main group compounds is emphasized, as is their similarity in reactivity to transition metal organometallic compounds.\n\nThe unexpectedly potent reactivity of the heavier main group species arises selleck products from the large differences in bonding between the light and heavy elements. Specifically, the energy levels within the heavier element molecules are separated by much smaller gaps as a result of generally lower bond strengths. In addition, the ordering and symmetries of the energy levels are generally different for their light

counterparts. Such differences lie at the heart of the new reactions. Moreover, the reactivity of the 3-deazaneplanocin A molecules can often be interpreted qualitatively in terms of simple molecular orbital considerations. More quantitative explanations are accessible from increasingly sophisticated density functional theory (DFT) calculations.\n\nWe open with a short description of the background

developments that led to this work. These advances involved the synthesis and characterization of numerous new main group molecules involving multiple bonds or unsaturated configurations; they were pursued over the latter part of the last century and the beginning of the new one. The results firmly established that the structures and bonding in the new compounds differed markedly from those of their lighter element congeners.

The knowledge gained from this fundamental work provided the framework for an understanding of their structures and bonding, and hence an understanding of the reactivity of the compounds discussed here.”
“There is no doubt that distance is the principal parameter that sets the order of magnitude for electron-tunneling rates in proteins. However, there continue to be varying ways to measure electron-tunneling distances in proteins. This distance uncertainty blurs the issue of whether the intervening protein medium has been naturally selected to speed or slow any particular electron-tunneling reaction. For redox cofactors lacking metals, an edge of the see more cofactor can be defined that approximates the extent in space that includes most of the wavefunction associated with its tunneling electron. Beyond this edge, the wavefunction tails off much more dramatically in space. The conjugated porphyrin ring seems a reasonable edge for the metal-free pheophytins and bacteriopheophytins of photosynthesis. For a metal containing redox cofactor such as heme, an appropriate cofactor edge is more ambiguous. Electron-tunneling distance may be measured from the conjugated heme macrocycle edge or from the metal, which can be up to 4.8 angstrom longer. In a typical protein medium, such a distance difference normally corresponds to a similar to 1000 fold decrease in tunneling rate.