pinecone/core-2020-05-10-deduplication huggingface dataset:
Can we predict reactivity for aromatic nucleophilic substitution with [ 18 F]fluoride ion?

The correlation between the  13 C‐NMR chemical shift of the aromatic ring carbon bearing the leaving group and the yield of nucleophilic aromatic displacement with no‐carrier‐added [ 18 F]fluoride ion was evaluated. In comparison of structurally analogous compounds (fluoro, nitro and trimethylammonium substituted benzaldehydes, benzophenones and benzonitriles), the  13 C‐NMR chemical shift of the reactive aryl ring carbon correlated quite well with the [ 18 F]fluorination yield (r 2 =0.87) for most but not all ring structures. Compounds with trimethylammonium leaving groups or methyl ring substituents were found to not fit the proposed correlation. Kinetic studies indicated clearly different rates of reaction for these compounds, with much higher than expected reactivity for the ccompounds with the cationic leaving group. Competition experiments suggest that low reactivity of methyl‐substituted rings may be due to conversion of [ 18 F]fluoride to an unreactive form. Our results indicate that the correlation between [ 18 F]fluorination yields for nucleophilic aromatic substitution reactions and the  13 C NMR chemical shift of the aryl ring carbon bearing the leaving group is applicable to numerous structurally analogous compounds, but cannot be simply generalized to aromatic rings with different leaving groups or ring substituents
Synthesis of N‐{N‐[4‐(4‐{ N ‐[ 11 C]methylamino}phenyl)butyryl]‐L‐prolyl}pyrrolidine: A potential radiotracer for prolyl endopeptidase

The synthesis of the 4‐[ 11  C]methylamino derivative of N‐{N‐[4‐(4‐Aminophenyl)butyryl]‐L‐prolyl}pyrrolidine (SUAM‐1221), is described as a potential marker for prolyl endopeptidase for  in vivo  positron emission tomography studies. Direct methylation of the 4‐amino derivative of SUAM‐1221 ( 1 ) with methyl iodide provided a mixture of the 4‐monomethyl ( 2 ) and 4‐dimethylamino ( 3 ) derivatives which were separated by chromatography. Methylation of  1  with [ 11  C]methyl iodide provided the 4‐[ 11 C]methylamino derivative of SUAM‐1221, ([ 11 C] 2 ), in 18–30% decay corrected radiochemical yield after HPLC purification, with a specific activity > 1700 Ci/mmol and a 40 minute synthesis time from end of bombardment
Synthesis of (N‐[ 11 C]methyl)Y‐29794, a competitive inhibitor of prolyl endopeptidase

Prolyl endopeptidase (PEP: [E.C.3.4.21.26]) is a widely distributed serine peptidase that cleaves a variety of oligopeptides in the brain and peripheral tissues. Y‐29794 ((2‐(8‐dimethylaminooctylthio)‐6‐isopropyl‐3‐pyridyl‐2‐thienyl ketone) is a potent competitive reversible inhibitor of this enzyme. In order to study the biodistribution of PEP  in vivo  we have synthesized (N‐[ 11 C]methyl)Y‐29794, by [ 11 C]alkylation of the N‐desmethyl precursor. The radiotracer was purified by silica gel Sep‐Pak and was obtained in 10‐17% yields (EOB: synthesis times shorter than 45 min) with >98% radiochemical purities and specific activities >550 Ci/mmol (EOS)
Synthesis of  N‐tert ‐butyl‐α‐(4‐[ 18 F]fluorophenyl)‐nitrone ([ 18 F]FPBN) for  in vivo  detection of free radicals

We have synthesized the fluorine‐18 labeled derivative of  N ‐ tert ‐butyl‐α‐phenylnitrone (PBN), a free radical spin trapping agent widely used with electron spin resonance (ESR).  N ‐ tert ‐Butyl‐α‐(4‐[ 18 F]fluorophenyl)‐nitrone ([ 18 F]FPBN) could be prepared with low radiochemical yield (3% decay corrected) by the direct aromatic nucleophilic substitution of  N ‐ tert ‐butyl‐α‐(4‐nitrophenyl)nitrone with [ 18 F]fluoride. An alternate two step synthesis route consisted of the nucleophilic [ 18 F]fluoride substitution of 4‐ N ,  N ,  N ‐trimethylammoniumbenzaldehyde triflate to yield 4‐[ 18 F]fluorobenzaldehyde, which was distilled into a vial containing  N ‐ tert ‐butyl‐hydroxylamine in 2N NaOH. 4‐[ 18 F]Fluorobenzaldehyde readily reacted with the hydroxylamine to form [ 18 F]FPBN. [ 18 F]FPBN was obtained in overall decay corrected yields of 24% in a total synthesis time < 45 min. and was suitable for further applications in  in vivo  studies of free radicals
Synthesis of β‐ 3 H‐mitotane for use in a rapid assay for mitotane metabolism

A  3 H + ‐release method has been developed for the assay of β‐hydroxylation of the adrenolytic drug mitotane. β‐ 3 H‐mitotane was synthesized by the reduction of 1‐(2‐chlorophenyl)‐1‐(4‐chlorophenyl)‐2,2,2‐trichloroethane by an aluminium‐Hg 2 Cl 2  couple in the presence of  3 H 2 O. For β‐hydroxylation of mitotane, the  3 H + ‐release assay is more efficient and sensitive than a method utilizing  14 C‐mitotane and chromatographic separation of metabolites by HPLC. The  3 H + ‐release assay has been used to evaluate the ability of adrenal tumors to metabolize mitotane via the β‐ hydroxylation route
Synthesis of [2‐{(4‐chlorophenyl) (4‐[ 125 I]iodophenyl)} methoxyethyl]‐1‐piperidine‐3‐carboxylic acid, [ 125 I]CIPCA: A potential radiotracer for GABA uptake sites

The synthesis of racemic [2‐{(4‐Chlorophenyl) (4‐iodophenyl)} methoxyethyl]‐1‐piperidine‐3‐carboxylic acid, (CIPCA) and its radioiodinated analog [ 125ß I]CIPCA is described. CIPCA was synthesized from 4‐iodobenzoyl chloride in five steps in 16% overall yield. Ammonium sulfate catalyzed solid‐state isotopic exchange of CIPCA with Na 125 I provided [ 125 I]CIPCA in 34% isolated radiochemical yield at a specific activity of 118 Ci/mmol. [ 125 ICIPCA] demonstrated moderate brain extraction and good  in vivo  radiostability in preliminary biodistribution studies conducted in CD‐1 mice. [ 125 I]CIPCA is a potentially useful radiotracer for study of the GABA uptake system
Application of neutral iridium(I) N-heterocyclic carbene complexes in ortho-directed hydrogen isotope exchange

Bench-stable complexes of the type [Ir(COD)(NHC)Cl] (NHC = N¬-heterocyclic carbene) have been investigated within the field of hydrogen isotope exchange. By employing a sterically encumbered NHC within such complexes and catalyst loadings of only 5 mol%, moderate to high deuterium incorporations were achieved across a range of aromatic ketones and nitrogen-based heterocycles. The simple and synthetically accessible catalysts reported herein present alternatives to phosphine-based species and increase the available labelling systems with respect to established iridium-based isotope exchange methodologie
Synthesis, characterization and 11C radiolabeling of aminophenyl benzothiazoles:structural effects on the alkylation of amino group

Several aminophenyl benzothiazoles were prepared with a view to using them as amyloid binding agents for imaging β-amyloid in Alzheimer\u27s disease. These precursors were radiolabeled with 11C-positron-emitting radioisotope using an automated synthesizer and selected radiolabeled compounds were further purified by HPLC. Our results demonstrate that changes in structure have a major influence on the radioactive yield and the ease with which the radiolabel can be introduced. Aminophenyl benzothiazoles with an attached isopropyl group resisted dialkylation perhaps due to steric hindrance caused by this group. Straight chain attachment of methyl, ethyl, butyl, and crotyl groups in the structure decreased the radiochemical yield. Notably, the o-aminophenyl benzothiazole derivatives were difficult to alkylate despite stringent experimental conditions. This reactivity difference is attributed to the hydrogen bonding characteristics of the o-amino group with the nitrogen atom of the thiazole ring
Development of a resonant-type microwave reactor and its application to the synthesis of positron emission tomography radiopharmaceuticals.

Microwave technology has been successfully applied to enhance the effectiveness of radiolabeling reactions. The use of a microwave as a source of heat energy can allow chemical reactions to proceed over much shorter reaction times and in higher yields than they would do under conventional thermal conditions. A microwave reactor developed by Resonance Instrument Inc. (Model 520/521) and CEM (PETWave) has been used exclusively for the synthesis of radiolabeled agents for positron emission tomography by numerous groups throughout the world. In this study, we have developed a novel resonant-type microwave reactor powered by a solid-state device and confirmed that this system can focus microwave power on a small amount of reaction solution. Furthermore, we have demonstrated the rapid and facile radiosynthesis of 16α-[(18)F]fluoroestradiol, 4-[(18)F]fluoro-N-[2-(1-methoxyphenyl)-1-piperazinyl]ethyl-N-2-pyridinylbenzamide, and N-succinimidyl 4-[(18)F]fluorobenzoate using our newly developed microwave reactor
Tritium labelling of a cholesterol amphiphile designed for cell membrane anchoring of proteins.

Cell membrane association of proteins can be achieved by the addition of lipid moieties to the polypeptide chain, and such lipid-modified proteins have important biological functions. A class of cell surface proteins contains a complex glycosylphosphatidylinositol (GPI) glycolipid at the C-terminus, and they are accumulated in cholesterol-rich membrane microdomains, that is, lipid rafts.  Semisynthetic lipoproteins prepared from recombinant proteins and designed lipids are valuable probes and model systems of the membrane-associated proteins. Because GPI-anchored proteins can be reinserted into the cell membrane with the retention of the biological function, they are appropriate candidates for preparing models via reduction of the structural complexity. A synthetic headgroup was added to the 3beta-hydroxyl group of cholesterol, an essential lipid component of rafts, and the resulting cholesterol derivative was used as a  simplified GPI mimetic. In order to quantitate the membrane integrated GPI mimetic after the exogenous addition to live cells, a tritium labelled cholesterol anchor was prepared. The radioactive label was introduced into the headgroup, and the radiolabelled GPI mimetic anchor was obtained with a specific  activity of 1.37 TBq/mmol. The headgroup labelled cholesterol derivative was applied to demonstrate the sensitive detection of the cell membrane association of the anchor under in vivo conditions
Enabling or "real" power and influence in leadership

On the theme of personal development, this conceptual article aims to provoke thought about power and influence in leadership by means of a short excursion into character depictions in J.R.R Tolkien’s The Lord of the Rings (1966). It is said of mythopoeic literature, the genre of Tolkien’s work, that the very simplicity of the lens “pares away distractions,” “opens the way to unexpected connections,...[and] draws attention to alternative modes of being and thinking” (Greene, 1994, p. 457). Taking the liberty of perceived applicability of Tolkien’s literary genius to motifs on leadership, this article provokes thinking on what constitutes “real” power and influence in leadership. It is contended that demonstrating real power and influence in leadership lies not in coercive tactics of wielding power over others but in withholding usurping power to work with and enable others to achieve worthwhile ends
The Institutionalization of Genocidal Leadership: Pol Pot and a Cambodian Dystopia

Misleadership is defi ned as leadership process involving a complex interplay of leader, follower, and situational elements, inscribing a vicious circle of intensifying dysfunctional action. It is tempting to see misleadership as the result of the madness of one leader. It is also misleading. Leadership research has been insuffi ciently attentive to misleadership and, in particular, to the misleadership factors intervening in genocidal processes. Discussed in the current article are the antecedents and the rule of the Khmer Rouge regime in Cambodia in the 1970s as an extreme case of misleadership. Lessons from the Polpotist dystopia are derived and refl ections on possible contra-strategies are presented. In particular, it is suggested that it is necessary to distinguish measures for social change that are admissible and positive, from negative utopian visions that are negative, inadmissible, and facilitative of evil leadership
Study of the influence of Beta-radiation on the properties and mineralization of different starch-based biomaterials

In this work, the effects of beta-radiation are assessed, for the first time, on starch-based biodegradable polymers, with the aim of using it as an alternative sterilization process to the previously studied sterilization methods. Different doses of radiation were used in order to investigate the possibility of using this sterilization technique as a treatment to tailor the surface and bulk properties (namely mechanical) of these polymers. The as-treated substrates were characterized by water-uptake measurements and contact angle (theta) measurements. The mechanical properties of the materials were characterized by tensile tests by means of ultimate tensile strength (UTS) and strain at break (epsilon). The fracture of the surfaces was observed by scanning electron microscopy (SEM). Dynamic mechanical analysis (DMA) was also used to characterize the viscolelastic behavior of the irradiated materials. The main effect of sterilization with beta-radiation over the starch-based polymers seems to be a surface modification by an increase of the hydrophilicity. Nevertheless, because beta-radiation did not significantly affect the mechanical properties, it can be regarded as an effective way of modifying the surface for applications were more hydrophilic surfaces are desirable
Pericardium of the frog, Rana esculenta, is morphologically designed as a lymphatic space

The importance of the pericardium and the pericardial fluid (PF) in the control of cardiac function has emerged over the past few years. Despite the acknowledgment that amphibians are exposed to both dehydration and excessive water accumulation, nothing is known about their pericardial structure and the morphological basis of the PF formation. We have studied the parietal pericardium (PP) morphology in Rana esculenta by electron microscopy. SEM images of the inner surface, which lines the pericardial cavity, revealed the presence of large vesicles and many small circular openings. TEM observations showed that the PP is made up of an inner mesothelial lining, often constituted by two layers of very flat cells lying on a basal membrane and of regularly oriented collagen bundles. The PP outer surface is lined by a layer of flat cells, without a basal membrane. The mesothelial cells had overlapping boundaries with complex intercellular connections and a rich pool of caveolae opened in the direction of both the pericardial cavity and intercellular spaces. These cells indicate an intense intracellular and/or intercellular transfer of fluids and substances. The intraperitoneal injection of the idromineral hormone, Val5-ANG II, induced PP modifications, particularly evident at the level of the structures involved in the transmesothelial traffic. These lymphatic-like traits suggest that the frog PP represents a large lymphatic sac, subject to paracrine-endocrine remodeling, which can actively adjust the PF, influencing the composition and volume of the myocardial interstitial fluid. © 2003 Wiley-Liss, Inc
Complex genital system of a haplogyne spider (Arachnida, Araneae, Tetrablemmidae) indicates internal fertilization and full female control over transferred sperm.

The female genital organs of the tetrablemmid Indicoblemma lannaianum are astonishingly complex. The copulatory orifice lies anterior to the opening of the uterus externus and leads into a narrow insertion duct that ends in a genital cavity. The genital cavity continues laterally in paired tube-like copulatory ducts, which lead into paired, large, sac-like receptacula. Each receptaculum has a sclerotized pore plate with associated gland cells. Paired small fertilization ducts originate in the receptacula and take their curved course inside the copulatory ducts. The fertilization ducts end in slit-like openings in the sclerotized posterior walls of the copulatory ducts. Huge masses of secretions forming large balls are detectable in the female receptacula. An important function of these secretory balls seems to be the encapsulation of spermatozoa in discrete packages in order to avoid the mixing of sperm from different males. In this way, sperm competition may be completely prevented or at least severely limited. Females seem to have full control over transferred sperm and be able to express preference for spermatozoa of certain males. The lumen of the sperm containing secretory balls is connected with the fertilization duct. Activated spermatozoa are only found in the uterus internus of females, which is an indication of internal fertilization. The sperm cells in the uterus internus are characterized by an extensive cytoplasm and an elongated, cone-shaped nucleus. The male genital system of I. lannaianum consists of thick testes and thin convoluted vasa deferentia that open into the wide ductus ejaculatorius. The voluminous globular palpal bulb is filled with seminal fluid consisting of a globular secretion in which only a few spermatozoa are embedded. The spermatozoa are encapsulated by a sheath produced in the genital system. The secretions in females may at least partly consist of male secretions that could be involved in the building of the secretory balls or play a role in sperm activation. The male secretions could also afford nutriments to the spermatozoa
Lymph Drainage of the Mammary Glands in Female Cats

The mammary gland is a common site of neoplasms in the female cat. All the malignant tumors metastasize to a lesser or a greater extent through the lymphatic system. However, the anatomical knowledge of this system is not sufﬁciently well known in cats to develop a reasoned model for the extirpation of these glands in case of malignant tumors. A study of the lymph drainage in 50 female cats was done by indirect injection in vivo of India ink inside the mammary parenchyma. After a waiting interval, mammary glands were extracted and the thoracic cavity opened. All the lymph nodes were examined after clearing. The success rate of the colorations of lymph nodes and lymph vessels was 91.8%. Out of the 100 observed mammary chains, the two intermediate mammary glands (T2, A1) may drain caudally to the superﬁcial inguinal lymph center and/or cranially to the axillary lymph center. The T1 gland always drains exclusively cranially and A2 exclusively caudally. The two mammary glands (T1 and A1) often drain towards the sternal cranial lymph nodes, but 100% of the T2 drain towards it. This research assumes that the limit between the two directions of drainage can exist only between glands T2 and A1. The results obtained with the study of the 1st, 2nd, 3rd, and 4th mammary glands permit production of new and more complete data of functional signiﬁcance that will eventually aid block dissection surgical technique in the removal of malignant tumors in cats. J. Morphol. 000: 000 – 000, 2005. © 2005 Wiley-Liss, Inc. to the inguinal region (Barone, 1996). Generally, the anterior pair of glands is affected and metastases frequently involve the regional lymph nodes and lungs (Hayden and Nielsen, 1971). Earliest surgical excision is the most effective therapy for any mammary tumor. In the cat, few surgical techniques are used in the treatment of mammary tumors (Hayes and Mooney, 1985). Surgical removal of all the glands on the affected side is a common method of treatment. Block dissection surgical techniques involve the removal of the affected mammary glands together with their lymphatic connections with other glands, the lymph nodes toward which these glands drain, and the other glands with which they are connected (Mann, 1984). The application of this technique is very limited in female cats due to the lack of sufﬁcient data on the anatomy of the lymphatic system draining the glands. The few works, when available, are based on a very limited number of animals (Sugimura et al., 1956; Meier, 1989). For these reasons, we decided to investigate the lymphatic drainage and the lymphatic connections between mammary glands in cats, with the aim of developing a reasoned model for the extirpation of these glands in cases of malignant tumors
Uterine epithelial changes during placentation in the viviparous skink Eulamprus tympanum

We used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to describe the complete ontogeny of simple placentation and the development of both the yolk sac placentae and\ud
chorioallantoic placentae from nonreproductive through\ud
postparturition phases in the maternal uterine epithelium\ud
of the Australian skink, Eulamprus tympanum. We chose E. tympanum, a species with a simple, noninvasive\ud
placenta, and which we know, has little net nutrient\ud
uptake during gestation to develop hypotheses about\ud
placental function and to identify any difference between\ud
the oviparous and viviparous conditions. Placental differentiation into the chorioallantoic placenta and yolk\ud
sac placenta occurs from embryonic Stage 29; both placentae\ud
are simple structures without specialized features\ud
for materno/fetal connection. The uterine epithelial cells\ud
are not squamous as previously described by Claire\ud
Weekes, but are columnar, becoming increasingly attenuated\ud
because of the pressure of the impinging underlying\ud
capillaries as gestation progresses. When the\ud
females are nonreproductive, the luminal uterine surface\ud
is flat and the microvillous cells that contain electrondense vesicles partly obscure the ciliated cells. As vitellogenesis progresses, the microvillous cells are less hypertrophied than in nonreproductive females. After ovulation and fertilization, there is no regional differentiation of the uterine epithelium around the circumference of the egg. The first differentiation, associated with the chorioallantoic placentae and yolk sac placentae, occurs at embryonic Stage 29 and continues through to Stage 39. As gestation proceeds, the uterine chorioallantoic placenta forms ridges, the microvillous cells become less hypertrophied, ciliated cells are less abundant, the underlying blood vessels increase in size, and the gland openings at the uterine surface are more apparent. In contrast, the yolk sac placenta has no particular folding with cells having a random orientation and where the microvillous cells remain hypertrophied throughout gestation. However, the ciliated cells become less abundant as gestation proceeds, as also seen in the chorioallantoic placenta. Secretory vesicles are visible in the uterine lumen. All placental differentiation and cell detail is lostat Stage 40, and the uterine structure has returned to the nonreproductive condition within 2 weeks. Circulating progesterone concentrations begin to rise during late vitellogenesis, peak at embryonic Stages 28–30, and decline after Stage 35 in the later stages of gestation. The coincidence between the time of oviposition and placental differentiation demonstrates a similarity during gestation in the uterus between oviparous and\ud
simple placental viviparous squamates
Basilar papilla of the canary and zebra finch: A quantitative scanning electron microscopical description

Morphological parameters of the apical surface of canary and zebra finch basilar papillae were quantitatively evaluated by scanning electron microscopy. The papillar length is 1.6 mm in both species. The zebra-finch papilla has a larger number of hair cells and is wider in the apical half of the papilla as compared to the canary. These two small songbird species have the smallest number of hair cells and the smallest papillae of the bird species investigated to date. The orientation of the hair cells is much more homogenous as compared to other species. Also, the discrepancy in the number of stereovilli of neural and abneural hair cells is much larger than in other bird species. A detailed analysis of gradients across the papilla in the canary revealed that anatomical parameters change in the neural half, whereas they remain rather constant in the abneural half of the papilla. There were, however, no obvious borders that separated distinct hair cell populations in either species