21 research outputs found
Selective breeding for variations in patterns of mystacial vibrissae of mice: Bilaterally symmetrical strains derived from ICR stock
The establishment of certain patterns of mystacial vibrlssae in mice has been the aim of an extensive breeding program carried on in this laboratory since 1977. In a companion paper we have reported on variations in this pattern in an outbred population of ICR mice. Starting with 21 ICR animals we bred, mostly by brother-sister mating, for 13 bilaterally symmetric patterns of mystacial vibrlssae characterized by the presence (or absence) of supernumerary whiskers (SWs). The strains are classified as follows: I, a mouse strain with the standard pattern; II, eight strains bred for the occurrence of SWs at a given site or sites; and III, four mouse strains bred for a maximal number of SWs in different regions of the whiskerpad. Commonly, SWs occur in regions that coincide with the zones of mergence between the three facial processes except for two class II strains in which we bred for SWs in the "straddler” row of vibrissae, and for one class III strain, In which we cultivated the tendency (that appeared late in our program) to have SWs at the crest of a facial process. For classes I and II we analyzed the results for about 18 generations in terms of "Improvement,” meaning an increase in the percentages of animals with the desired phenotype together with a decreased frequency of undesired SWs. For class III, success in breeding meant the increase of the mean number of the desired SWs. All results led to the same conclusion: there is a genetic basis for the occurrence of SWs. The side preference of a particular SW is not strain dependent. It disappears in those class I and II strains in which almost 100% of animals obtained the desired phenotype. The increase in number of SWs in one zone of mergence does not depend on the presence of SWs in the other. Where tested, we almost always found a representation of an SW in a topologically equivalent location within the "barrelfield” area of the somatosensory cerebral cortex. Except for some diseases early in the breeding program, and some side effects of inbreeding that were eliminated, the population was without obvious defects. Where tested, there was no correlation between the occurrence of SWs and sex. The observed variations in pattern of mystacial vibrlssae and their genetic background led us to propose a morphogenetic model for the formation of the pattern of mystacial vibrlssa
Cleaning deteriorated elements of ammunition: Development of a procedure applied to cartridge cases from the Second World War.
Deteriorated elements of ammunition can be found while investigating different types of events. Exposure to adverse environmental conditions may lead to metal alteration (corrosion) or organic material deposition (contaminations) on the exposed elements of ammunition. From a forensic perspective, both types of deterioration pose challenges when observing marks left by the firearms used to discharge the corresponding ammunition (e.g. firing pin, extractor). The longer the time of exposure to the adverse environmental conditions, the more challenging the observation of such marks. A literature review highlighted three previously published restorative methods used to clean deteriorated elements of ammunition. The aim of this research is to develop a cleaning procedure applicable to cartridge cases exposed to adverse environmental conditions, while avoiding the degradation of marks left by the firearms used to discharge the corresponding ammunition. A first batch of 21 brass cartridge cases dating back to the Second World War (WWII) was used to develop a cleaning sequence involving the three methods. The efficiency of each restorative method was qualitatively assessed using optical macroscopy and the Evofinder® ballistic identification system. The developed sequence relies on successive applications of Tickopur® TR 7 (a diluted soft metal cleaner), sulfuric acid and finally Aqua Regia (HCl 37% and HNO <sub>3</sub> 75%), all of them involving ultrasonic baths. The resulting cleaning sequence was subsequently applied to three batches of Second World War cartridge cases discovered in France and Russia. This sequential procedure allows the effective cleaning of WWII brass cartridge cases while highlighting different marks left by firing pins, extractors, ejectors, and breech faces. Applying a forensic analysis and comparison process to the marks highlighted on these elements of ammunition can support the verification of historical facts when reconstructing events which took place more than seventy years ago
Enantioselective Hydroxylation of Benzylic C(sp; 3; )-H Bonds by an Artificial Iron Hydroxylase Based on the Biotin-Streptavidin Technology
The selective hydroxylation of C-H bonds is of great interest to the synthetic community. Both homogeneous catalysts and enzymes offer complementary means to tackle this challenge. Herein, we show that biotinylated Fe(TAML)-complexes (TAML = Tetra Amido Macrocyclic Ligand) can be used as cofactors for incorporation into streptavidin to assemble artificial hydroxylases. Chemo-genetic optimization of both cofactor and streptavidin allowed optimizing the performance of the hydroxylase. Using H; 2; O; 2; as oxidant, up to ∼300 turnovers for the oxidation of benzylic C-H bonds were obtained. Upgrading the ee was achieved by kinetic resolution of the resulting benzylic alcohol to afford up to >98% ee for (; R; )-tetralol. X-ray analysis of artificial hydroxylases highlights critical details of the second coordination sphere around the Fe(TAML) cofactor
Probing the interplay between lattice dynamics and short-range magnetic correlations in CuGeO3 with femtosecond RIXS
Investigations of magnetically ordered phases on the femtosecond timescale
have provided significant insights into the influence of charge and lattice
degrees of freedom on the magnetic sub-system. However, short-range magnetic
correlations occurring in the absence of long-range order, for example in
spin-frustrated systems, are inaccessible to many ultrafast techniques. Here,
we show how time-resolved resonant inelastic X-ray scattering (trRIXS) is
capable of probing such short-ranged magnetic dynamics in a charge-transfer
insulator through the detection of a Zhang-Rice singlet exciton. Utilizing
trRIXS measurements at the O K-edge, and in combination with model
calculations, we probe the short-range spin-correlations in the frustrated spin
chain material CuGeO3 following photo-excitation, revealing a strong coupling
between the local lattice and spin sub-systems
Examining the surface phase diagram of IrTe with photoemission
In the transition metal dichalcogenide IrTe, low-temperature
charge-ordered phase transitions involving Ir dimers lead to the occurrence of
stripe phases of different periodicities, and nearly degenerate energies.
Bulk-sensitive measurements have shown that, upon cooling, IrTe undergoes
two such first-order transitions to and
reconstructed phases at ~K and ~K,
respectively. Here, using surface sensitive probes of the electronic structure
of IrTe, we reveal the first-order phase transition at ~K to
the stripes phase, previously proposed to be the surface ground
state. This is achieved by combining x-ray photoemission spectroscopy and
angle-resolved photoemission spectroscopy, which give access to the evolution
of stripe domains and a particular surface state, the energy of which is
dependent on the Ir dimer length. By performing measurements over a full
thermal cycle, we also report the complete hysteresis of all these phases
Selective breeding for variations in patterns of mystacial vibrissae of mice. Bilaterally symmetrical strains derived from ICR stock
The establishment of certain patterns of mystacial vibrissae in mice has been the aim of an extensive breeding program carried on in this laboratory since 1977. In a companion paper we have reported on variations in this pattern in an outbred population of ICR mice. Starting with 21 ICR animals we bred, mostly by brother-sister mating, for 13 bilaterally symmetric patterns of mystacial vibrissae characterized by the presence (or absence) of supernumerary whiskers (SWs). The strains are classified as follows: I, a mouse strain with the standard pattern; II, eight strains bred for the occurrence of SWs at a given site or sites; and III, four mouse strains bred for a maximal number of SWs in different regions of the whiskerpad. Commonly, SWs occur in regions that coincide with the zones of mergence between the three facial processes except for two class II strains in which we bred for SWs in the "straddler" row of vibrissae, and for one class III strain, in which we cultivated the tendency (that appeared late in our program) to have SWs at the crest of a facial process. For classes I and II we analyzed the results for about 18 generations in terms of "improvement," meaning an increase in the percentages of animals with the desired phenotype together with a decreased frequency of undesired SWs. For class III, success in breeding meant the increase of the mean number of the desired SWs. All results led to the same conclusion: there is a genetic basis for the occurrence of SWs. The side preference of a particular SW is not strain dependent. It disappears in those class I and II strains in which almost 100% of animals obtained the desired phenotype. The increase in number of SWs in one zone of mergence does not depend on the presence of SWs in the other. Where tested, we almost always found a representation of an SW in a topologically equivalent location within the "barrelfield" area of the somatosensory cerebral cortex. Except for some diseases early in the breeding program, and some side effects of inbreeding that were eliminated, the population was without obvious defects. Where tested, there was no correlation between the occurrence of SWs and sex. The observed variations in pattern of mystacial vibrissae and their genetic background led us to propose a morphogenetic model for the formation of the pattern of mystacial vibrissae
From hepa.ch to COMPI – Internet-based exchange platforms for physical activity promotion professionals in Switzerland
Information technology can make an important contribution to the promotion of sport for all and physical activity in a number of different fields. Internet-based exchange platforms for physical activity promotion professionals are such a possibility. In Switzerland, there are currently 18 platforms, 17 of them are owned by institutions, one by a private individual. 4 of the Web sites are dealing with physical activity in a global and universal sense, 6 with either physical education or organised sports. Another 8 Web sites cover different dimensions of prevention or health promotion including physical activity. Information technology can greatly facilitate the transport of information. However, it cannot replace personal interaction. Therefore, most of the Web sites for physical activity promotion professionals provide interactive elements such as online fora, opportunities to request individual support and registrations for real-life meetings and events
Unconventional Fragment Usage Enables a Concise Total Synthesis of (−)-Callyspongiolide
An asymmetric synthesis of (−)-callyspongiolide
is described.
The route builds the macrolide domain atypically from a disaccharide
and a monoterpene without passing through a <i>seco</i>-acid.
Chiral iridium catalysis selectively joins fragments. Subsequent degradation
of an imbedded butyrolactone via perhemiketal fragmentation affords
a stereo- and regio-defined homoallylic alcohol that is engaged directly
in a carbonylative macrolactonization. Further elaboration of the
polyunsaturated appendage provides the natural product in a particularly
direct and flexible manner
Unconventional Fragment Usage Enables a Concise Total Synthesis of (−)-Callyspongiolide
An asymmetric synthesis of (−)-callyspongiolide
is described.
The route builds the macrolide domain atypically from a disaccharide
and a monoterpene without passing through a <i>seco</i>-acid.
Chiral iridium catalysis selectively joins fragments. Subsequent degradation
of an imbedded butyrolactone via perhemiketal fragmentation affords
a stereo- and regio-defined homoallylic alcohol that is engaged directly
in a carbonylative macrolactonization. Further elaboration of the
polyunsaturated appendage provides the natural product in a particularly
direct and flexible manner