The reaction force and the transition region of a reaction

The reaction force F(R) and the position-dependent reaction force constant κF(R) are defined by F(R)=-∂V(R)/∂R and κ(R)=∂²V(R)/∂R², where V(R) is the potential energy of a reacting system along a coordinate R. The minima and maxima of F(R) provide a natural division of the process into several regions. Those in which F(R) is increasing are where the most dramatic changes in electronic properties take place, and where the system goes from activated reactants (at the force minimum) to activated products (at the force maximum). κ(R) is negative throughout such a region. We summarize evidence supporting the idea that a reaction should be viewed as going through a transition region rather than through a single point transition state. A similar conclusion has come out of transition state spectroscopy. We describe this region as a chemically-active, or electronically-intensive, stage of the reaction, while the ones that precede and follow it are structurally-intensive. Finally, we briefly address the time dependence of the reaction force and the reaction force constant.     

The BglG group of antiterminators: a growing family of bacterial regulators

The product of the bglG gene of Escherichia coli was among the first bacterial antiterminators to be identified and characterized. Since the elucidation ten years ago of its role in the regulation of the bgl operon of E. coli,a large number of homologies have been discovered in both Gram-positive and Gram-negative bacteria. Often the homologues of BglG in other organisms are also involved in regulating β-glucoside utilization. Surprisingly, in many cases, they mediate antitermination to regulate a variety of other catabolic functions. Because of the high degree of conservation of the cis-acting regulatory elements, antiterminators from one organism can function in another. Generally the antiterminator protein itself is negatively regulated by phosphorylation by a component of the phosphotransferase system. This family of proteins thus represents a highly evolved regulatory system that is conserved across evolutionarily distant genuses.     

Perioperative Management of a Patient with a Nonresectable Pheochromocytoma

ObjectiveTo describe the clinical course of a patient with a nonresectable pheochromocytoma during urgent hip surgery.MethodsTo describe the clinical management and postoperative outcome of the patient and review the relevant literature.ResultsAn 85-year-old male with a nonresectable pheochromocytoma required urgent hip surgery following a traumatic hip fracture. He was perioperatively managed with phenoxybenzamine, metyrosine, and metoprolol to avoid potential pheochromocytoma-related complications. He remained hemodynamically stable and recovered from the surgery without complications.ConclusionsThis case illustrates the successful management of a patient requiring urgent surgery in the setting of a nonresectable pheochromocytoma, which is rarely described in the literature. (Endocr Pract. 2013;19: e74-e76     

Mechanism of intermolecular hydroacylation of vinylsilanes catalyzed by a rhodium(I) olefin complex: a DFT study

Density functional theory (DFT) was used to investigate the Rh(I)-catalyzed intermolecular hydroacylation of vinylsilane with benzaldehyde. All intermediates and transition states were optimized completely at the B3LYP/6-31G(d,p) level (LANL2DZ(f) for Rh). Calculations indicated that Rh(I)-catalyzed intermolecular hydroacylation is exergonic, and the total free energy released is −110 kJ mol⁻¹. Rh(I)-catalyzed intermolecular hydroacylation mainly involves the active catalyst CA2, rhodium–alkene–benzaldehyde complex M1, rhodium–alkene–hydrogen–acyl complex M2, rhodium–alkyl–acyl complex M3, rhodium–alkyl–carbonyl–phenyl complex M4, rhodium–acyl–phenyl complex M5, and rhodium–ketone complex M6. The reaction pathway CA2 + R2 → M1b → T1b → M2b → T2b1 → M3b1 → T4b → M4b → T5b → M5b → T6b → M6b → P2 is the most favorable among all reaction channels of Rh(I)-catalyzed intermolecular hydroacylation. The reductive elimination reaction is the rate-determining step for this pathway, and the dominant product predicted theoretically is the linear ketone, which is consistent with Brookhart’s experiments. Solvation has a significant effect, and it greatly decreases the free energies of all species. The use of the ligand Cp′ (Cp′ = C₅Me₄CF₃) decreased the free energies in general, and in this case the rate-determining step was again the reductive elimination reaction.     

Candida parapsilosis meningitis in a patient with AIDS. Report of a case and review of the literature

BackgroundCandida parapsilosis is an important species in the genus Candida that plays a significant role in hospitalized patients with nosocomial infections. In patients with HIV infection or AIDS, central nervous system involvement by Candida species is exceptional.Case reportHere we report a case of an acute meningoencephalitis due to C. parapsilosis in an adult patient with AIDS. We describe the clinical manifestations, the diagnosis methods, antifungal therapy and outcome.ConclusionsC. parapsilosis is uncommonly reported as a cause of meningitis in AIDS patients. A higher index of suspicion and culture is necessary to confirm the diagnosis of candidal meningoencephalitis.     

Nucleosides and Nucleotides. 192. Toward the Total Synthesis of Cyclic ADP-Carbocyclic-Ribose. Formation of the Intramolecular Pyrophosphate Linkage by a Conformation-Restriction Strategy in a Syn-form Using a Halogen Substitution at the 8-Position of the Adenine Ring

Abstract

The synthesis of cyclic ADP-carbocyclic-ribose (2), as a stable mimic for cyclic ADP-ribose, was investigated. Construction of the 18-membered backbone structure was successfully achieved by condensation of the two phosphate groups of 19, possibly due to restriction of the conformation of the substrate in a syn-form using an 8-chloro substituent at the adenine moiety. SN2 reactions between an optically active carbocyclic unit 8, which was constructed by a previously developed method, and 8-bromo-N ⁶-trichloroacetyl-2′,3′-O-isopropylideneadenosine 9c gave N-1-carbocyclic derivative, which was deprotected to give 5′,5′-diol derivatives 18. When 18 was treated with POCl₃ in PO(OEt)₃, the bromo group at the 8-position was replaced to give N-1-carbocyclic-8-chloroadenosine 5′,5′-diphosphate derivative 19 in 43% yield. Treatment of 19 with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride gave the desired intramolecular condensation product 20 in 10% yield. This is the first chemical construction of the 18-membered backbone structure containing an intramolecular pyrophosphate linkage of a cADPR-related compound with an adenine base.     

Synthesis and Biological Evaluation of a Carbocyclic Azanoraristeromycin Siderophore Conjugate

Abstract

Synthesis and biological evaluation of a carbocyclic azanoraristeromycin siderophore conjugate 22 is reported. Coupling of previously prepared L-alanyl-4′-azanoraristeromycin 19 with protected tripeptide trihydroxamate 20, followed by hydrogenolytic removal of all protecting groups, provided the first carbocylic azanoraristeromycin siderophore conjugate (22, 8 with iron). Compounds 19 and 22 showed inhibitory activity against tumor cells, and conjugate 22, in particular, displayed significant activity against those viruses (i.e. reo, parainfluenza, vaccinia, cytomegalo) that are known to be inhibited by S-adenosylhomocysteine hydrolase inhibitors.     

Stenogrammitis, a new genus of grammitid ferns segregated from Lellingeria (Polypodiaceae)

Stenogrammitis , a new genus of grammitid ferns, is segregated from Lellingeria based on morphological and molecular evidence. It differs from Lellingeria by linear leaves usually less than 5 mm wide, clathrate iridescent rhizome scales that are glabrous except for a single apical cilium, veins unbranched and only one per segment, fertile veins usually with the dark sclerenchyma visible beneath the sporangia, and x = 33. In contrast, Lellingeria has broader laminae, veins pinnate within the segments, and fertile veins not visible beneath the sporangia. Melpomene, which is sister to Stenogrammitis and Lellingeria, differs from those two genera by reddish setae on the leaves and rhizome scales papillate at the apex. Some species of Stenogrammitis are also distinctive by hemidimorphic laminae that have the fertile portion less dissected than the sterile. Stenogrammitis is pantropical and currently comprises 24 species, 12 of which occur in the Neotropics, six in Africa, four in Madagascar, and two on Pacific Islands. New combinations are made for Stenogrammitis aethiopica, S. anamorphosa, S. ascensionensis, S. boivinii, S. delitescens, S. jamesonii, S. hartii, S. hellwigii, S. hildebrandtii, S. limula, S. luetzelburgii, S. myosuroides, S. nutata, S. oosora, S. paucipinnata, S. prionodes, S. pumila, S. ruglessii, S. rupestris, S. saffordii, S. strangeana, S. tomensis, S. subcoriacea, and S. wittigiana. Lectotypifications are made for Grammitis muscosa, Polypodium itatiayense, P. oosorum var. micropecten, P. serrulatum forma major, P. serrulatum forma minor, S. luetzelburgii, S. myosuroides, and S. wittigiana. Illustrations are presented for the diagnostic characters of the genus, as well as a map with the geographical distribution.     

A DNA fragment fromStreptomyces fradiae increases the production of a metalloprotease inStreptomyces lividans

Streptomyces fradiae produces several extracellular proteases and many of these are inducible. An 8.8 kb DNA fragment of Streptomyces fradiae cloned on pIJ699 caused increased protease activity in Streptomyces lividans.Clones carrying this recombinant plasmid showed a significant delay in sporulation. A protein of 18 kDa was purified from the extracellular proteins secreted by the host carrying the recombinant plasmid. Further characterization showed that this protease is a metalloprotease.     

Synthesis and Conformational Analysis of a Locked Analogue of Carbovir Built on a Bicyclo[3.1.0]-hex-2-enyl Template

Abstract

The synthesis and biological evaluation of a carbovir analogue (5) built on a bicyclo[3.1.0]hex-2-enyl template is described. A conformational analysis using density functional theory at the B3LYP/6-31G* level has been carried out on the rigid pseudosugar template of 5, the cyclopentene moiety of carbovir and the bicyclo[3.1.0]hex-2-yl pseudosugars of two isomeric carbonucleosides (12 and 13) containing exo- and endo-fused cyclopropane rings. The results show that while the planar configuration of the fused cyclopentane ring of compound 5 helps retain weak anti-HIV activity, the ability of the cyclopentene ring of carbovir to easily adopt a planar or puckered conformation with little energy penalty may prove to be a crucial advantage. The bicyclo[3.1.0]hex-2-yl nucleosides 12 and 13 that were inactive against HIV exhibited stiffer resistance to having a planar, fused cyclopentane moiety.     

Synthesis of a Prostaglandin Intermediate and Synthesis of Dihydrojasmone and Methyl Dihydrojasmonate

The synthesis of 2-(6-methoxycarbonylhexyl)cyclopent-2-ene-1-one (5), a valuable intermediate in the synthesis of prostaglandins, is described starting from ethyl 3-oxoglutarate (1). The same reaction sequence also produces dihydrojasmone (12) and methyl dihydrojasmonate (13).     

Nothotalisia, a new genus of Picramniaceae from tropical America

A new genus of Picramniaceae from tropical America, Nothotalisia, is described. Of the three species in the genus, N. piranii and N. cancellata, are new to science. The third, N. peruviana, was originally described as Talisia peruviana in the Sapindaceae. The genus and all three species are described, illustrated, and distinguished by means of a key.     

The role of cortical area MST in a model of combined smooth eye-head pursuit

The cortical medial superior temporal area (MST) is essential for the normal execution of smooth pursuit eye movements. Many pursuit-related neurons (visual-tracking neurons = VT neurons) in the lateral part of area MST (MSTl) are responsive to retinal image slip (r) as well as to eye (e) and head velocity (h) with similar preferred directions (isodirectionality). We show, by running a connectionist network with VT neuron-like elements, that an assembly of MSTl-VT neurons is able to reconstruct target motion in world-centered coordinates (t′). When t′ is fed into a subsequent model stage, converting t′ into gaze velocity (g′) with varying contributions of e and h, the overall model is able to account for many of the salient properties of visually guided pursuit including the consequences of MSTl lesions. However, the analysis of the MSTl network also clearly indicates that isodirectionality is not a prerequisite for its performance. The investigation of a second model suggests that isodirectionality indeed does not result from functional but from developmental constraints. This second model is a connectionist network with hidden units, which similar to MSTl-VT neurons receive input from modality specific units encoding retinal slip, eye and head velocity. After training this network to offer t′ as output, two subsets of hidden units emerged, one exhibiting isodirectionality, but not the other. Since only isodirectional hidden units contributed to the flow of information, the preponderance of isodirectional MSTl-VT neurons might be the result of developmental pruning, eliminating the second group. Received: 17 April 1998 / Accepted in revised form: 28 July 1998     

Synthesis, characterization, and evaluation of a novel 99mTc(CO)3 pyrazolyl conjugate of a peptide nucleic acid sequence

The 16-mer peptide nucleic acid sequence H-A GAT CAT GCC CGG CAT-Lys-NH₂ (1), which is complementary to the translation start region of the N-myc oncogene messenger RNA, was synthesized and conjugated to a pyrazolyl diamine bifunctional chelator (pz). The novel conjugate pz-A GAT CAT GCC CGG CAT-Lys-NH₂ (2) was labeled with technetium tricarbonyl, yielding quantitatively the complex fac-[^99mTc(CO)₃(κ³-pz-A GAT CAT GCC CGG CAT-Lys-NH₂)]²⁺ (4). Complex 4 was obtained with high radiochemical purity and high specific activity, revealing high stability in human serum and in cell culture medium. The identity of 4 was confirmed by comparing its reversed-phase high performance liquid chromatography profile with that of the rhenium analog fac-[Re(CO)₃(κ³-pz-A GAT CAT GCC CGG CAT-Lys-NH₂)]²⁺ (3), prepared by conjugation of fac-[Re(CO)₃(3,5-Me₂pz(CH₂)₂N((CH₂)₃COOH)(CH₂)₂NH₂)]⁺ to 1, using solid-phase techniques. UV melting experiments of 1 and 3 with the complementary DNA sequence led to the formation of stable duplexes, indicating that the conjugation of 1 to the pyrazolyl chelator and to the metal fragment fac-[M(CO)₃]⁺ did not affect the recognition of the complementary sequence as well as the duplex stability. For a first screening, SH-SY5Y human neuroblastoma cells, which express N-myc, were treated with 4. The results show that 4 internalizes (7% of the activity goes into the cells, after 4 h at 37 °C), presenting also a relatively high cellular retention (only 40% of internalized activity is released from the cells after 5 h). An erratum to this article can be found at     

Intersession reliability of a posturo-stabilometric test,using a force platform

Aim of the studyTo evaluate the intersession reliability of a posturo-stabilometric examination.MethodsSingle blind clinical trial conducted in two sessions over two weeks.44 healthy volunteers free from postural and temporomandibular disorders. All the subjects complied with the criteria for completing the study.All the subjects underwent two sessions of posturo-stabilometric examinations in different visual and mandibular conditions.Sway area, sway length and the coordinates of the center of pressure were evaluated and statistically analyzed using the Intraclass correlation coefficient (ICC).ResultsAll the posturo-stabilometric parameters seemed to have an excellent reproducibility with overall ICCs higher than 70% and good confidence intervals except for the sway area (ICC 0.422 with CI 0.283–0.560 with open eyes and ICC 0.554 with CI 0.424–0.683 with closed eyes).ConclusionsThe posturo-stabilometric examination carried out using a force platform has a good intrasession and intersession reliability, especially considering sway velocity, COP X and COP Y parameters. The force platform usefulness in analyzing static posture is confirmed in any medical field.     

Evaluating a sensitive issue: reliability of a clinical evaluation for allodynia severity

Abstract

Purpose/Aim: Allodynia is a common feature of neuropathic pain with few validated clinical evaluation options. We identified a need to estimate the measurement properties of the standardised evaluation procedure for static mechanical allodynia severity popularised by the somatosensory rehabilitation of pain method, known as the rainbow pain scale. This study (www.clinicaltrials.gov. NCT02070367) undertook preliminary investigation of the inter-rater and test-retest reliability of the rainbow pain scale.

Methods: Persons with pain in one upper extremity after Complex Regional Pain Syndrome, a peripheral nerve injury or a recent hand fracture were recruited for assessment of static mechanical allodynia threshold using calibrated monofilaments by two raters at baseline, and repeated assessment one week later.

Results: Single measures estimates suggested inter-rater reliability was substantial for the rainbow pain scale [intra-class correlation coefficient?=?0.78 (n?=?31), p?<?0.001]. Test-retest reliability was also excellent at with an intraclass correlation coefficient of 0.87 [n?=?28, p?<?0.001]. However, confidence intervals suggest the true values could be more moderate, with lower bounds of the 95% confidence interval at 0.60 and 0.74, respectively.

Conclusions: This pilot study has generated preliminary support for the inter-rater and test-retest reliability of the rainbow pain scale. Future studies should seek to increase confidence in estimates of reliability, and estimate validity and responsiveness to change in persons with somatosensory disorders.     

医院行政管理人员培训需求的调查研究

目的 明确医院行政管理队伍培训需求,为建立规范化培训体系,提高医院管理水平奠定基础。方法 采用问卷调查法,面向医院行政管理人员开展个人培训需求意愿、医院内部管理体系运行现状及个人岗位胜任能力调查,在此基础上进行组织、岗位及个人层面的培训需求分析。结果 医院行政管理人员接受培训的意愿较为突出,而不同层级之间对培训内容、时间及方式的需求存在明显差异。结论 医院行政管理人员具有较为强烈的培训需求,建立一套科学实用的长效培训机制是建设高素质医院管理队伍的基础性工程。     

New genera and species of Jumping Ground Bugs (Hemiptera: Schizopteridae) in Dominican and Burmese amber,with a description of a meloid (Coleoptera: Meloidae) triungulin on a Burmese specimen

New genera and species of jumping ground bugs (Hemiptera: Schizopteridae) are described in Dominican and Burmese amber. In Dominican amber are described: Hypselosoma dominicana Poinar & Brown sp. n., Schizoptera dominicana Poinar sp. n. and Schizoptera hispaniolae Poinar sp. n. In Burmese amber are described: Lumatibialis burmitis Poinar gen. et sp. n. and Hexaphlebia burmanica Poinar gen. et sp. n. A triungulin attached to the dorsum of the abdomen of Lumatibialis burmitis is described as Microentomus epibatus Poinar gen. et sp. n. in the family Meloidae (Coleoptera). This specimen represents the oldest known triungulin and the first fossil phoretic association of a triungulin and hemipteran.     

Tandem photoaffinity labeling of a target protein using a linker with biotin,alkyne and benzophenone groups and a bioactive small molecule with an azide group

A novel linker containing biotin, alkyne and benzophenone groups (1) was synthesized to identify target proteins using a small molecule probe. This small molecule probe contains an azide group (azide probe) that reacts with an alkyne in 1 via an azide–alkyne Huisgen cycloaddition. Cross-linking of benzophenone to the target protein formed a covalently bound complex consisting of the azide probe and the target protein via 1. The biotin was utilized via biotin–avidin binding to identify the cross-linked complex. To evaluate the effectiveness of 1, it was applied in a model system using an allene oxide synthase (AOS) from the model moss Physcomitrella patens (PpAOS1) and an AOS inhibitor that contained azide group (3). The cross-linked complex consisting of PpAOS1, 1 and 3 was resolved via SDS–PAGE and visualized using a chemiluminescent system. The method that was developed in this study enables the effective identification of target proteins.