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PubMed1998

Volumetric assessment of airborne pollen and spore levels in Rochester, Minnesota, 1992 through 1995.

OBJECTIVE: To reassess airborne pollen counts and to study spore counts by volumetric collection in Rochester, Minnesota. MATERIAL AND METHODS: Samples of pollen and spores were collected from the top of a six-story building in downtown Rochester by use of a rotational rod sampler, which was activated for 30 seconds every 10 minutes for 24 hours a day, 5 days a week, from mid-April to mid-October 1992 through 1995. Particles were stained with Calberla's fluid and viewed microscopically by transmitted light. Identifications were substantiated by comparison with field-collected "known" materials and standard reference guides. Data were expressed as "particles retained/cubic meter of air sampled." RESULTS: Because the methods of collection varied, only qualitative comparisons could be made with a study done in Rochester more than 3 1/2 decades earlier. For tree pollens, a similar progression of appearance and seasonal duration were noted for most species. Alder (Alnus), willow (Salix), and hickory-pecan (Carya), however, were found to have distinctly longer seasons, and walnut (Julgans) was detected 2 weeks earlier in the season. The most frequently detected tree pollen had changed from oak (Quercus) to apple and crab apple (Malus), which was not reported at all previously. Ragweed (Ambrosia) was still found to peak at the end of August and had a similar duration. Study of grass and nettle pollen as well as the Amaranthaceae-Chenopodiaceae complex yielded findings similar to those in the prior investigation. Fungal spores were detected from April through October and represented a substantial percentage of the airborne allergens; Cladosporium, ascospores, and basidiospores were the most common. CONCLUSION: Volumetric assessment of airborne pollen and spore levels in Rochester, Minnesota, yielded useful information for clinicians in southern Minnesota that could help direct skin test selection.

Air↗

PubMed2004

Competitive interactions among raptors in boreal forests.

We examined inter-specific interactions among goshawks ( Accipiter gentilis), common buzzards (Buteo buteo) and honey buzzards (Pernis apivorus) in western Finland in 1983-1996. Because goshawks are among the largest birds of prey species in boreal forests they may take over the nest of smaller and less-competitive forest-dwelling raptors when searching for suitable places for breeding. Accordingly, more than half of newly established goshawk territories were found on the territories previously occupied by the common buzzard and the honey buzzard. Otherwise, territory sharing between these species was rare. Fledgling production of honey buzzards was not associated with the presence of goshawks, probably owing to the almost 2 months later onset of breeding. This probably decreases competitive interactions between these two species. An intensive interference competition, instead, seemed to be evident between common buzzards and goshawks, because the fledgling production of common buzzards was decreased by 20% as a result of failures during incubation and nestling period in the vicinity (<1 km) of occupied goshawk nests. Similarly, territory occupancy of common buzzards till the next breeding season was significantly reduced in the presence of goshawks. Relatively high proportions of occupied buzzard territories (17%) in the study area were shared by breeding goshawks on the same territory. This suggests that although their diets are dissimilar they inhabit similar habitats and might compete for the available prime nesting habitats within forest landscapes. In addition, goshawks benefit from taking over the complete nests of other raptors, imposing upon the original owners of the nest, because building a large stick nest is probably energetically costly. As a large raptor, the goshawk apparently has a competitive advantage over smaller ones, and may have an ever-increasing impact on smaller birds of prey, if there is a lack of sheltered forests inducing competition for the available nest sites.

Animals↗

PubMed1998

Evolution on a volcanic conveyor belt: using phylogeographic reconstructions and K-Ar-based ages of the Hawaiian Islands to estimate molecular evolutionary rates.

The Hawaiian Islands form as the Pacific Plate moves over a 'hot spot' in the earth's mantle where magma extrudes through the crust to build huge shield volcanos. The islands subside and erode as the plate carries them to the north-west, eventually to become coral atolls and seamounts. Thus islands are ordered linearly by age, with the oldest islands in the north-west (e.g. Kauai at 5.1 Ma) and the youngest in the south-east (e.g. Hawaii at 0.43 Ma). K-Ar estimates of the date of an island's formation provide a maximum age for the taxa inhabiting the island. These ages can be used to calibrate rates of molecular change under the following assumptions: (i) K-Ar dates are accurate; (ii) tree topologies show that derivation of taxa parallels the timing of island formation; (iii) populations do not colonize long after island emergence; (iv) the coalescent point for sister taxa does not greatly predate the formation of the colonized younger island; (v) saturation effects and (vi) among-lineage rate variation are minimal or correctable; and (vii) unbiased standard errors of distances and regressions can be estimated from multiple pairwise comparisons. We use the approach to obtain overall corrected rate calibrations for: (i) part of the mitochondrial cytochrome b gene in Hawaiian drepanidines (0.016 sequence divergence/Myr); (ii) the Yp1 gene in Hawaiian Drosophila (0.019/Myr Kambysellis et al. 1995); and (iii) parts of the mitochondrial 12S and 16S rRNA and tRNAval in Laupala crickets (0.024-0.102/Myr, Shaw 1996). We discuss the reliability of the estimates given the assumptions (i-vii) above and contrast the results with previous calibrations of Adh in Hawaiian Drosophila and chloroplast DNA in lobeliods.

Animals↗

PubMed2001

New opportunities and proven approaches in complementary and alternative medicine research at the National Institutes of Health.

This presentation describes some of the issues that arise when applying the clinical-trial approach of conventional medicine to complementary and alternative medicine (CAM) modalities. Conventional medicine has been making the evolution to using an evidence base and to making recommendations only when the evidence is strong. The National Center for Complementary Medicine (NCCAM), one of twenty-five Institutes or Centers of the National Institutes of Health (NIH), is working to hold CAM to the same high standards, not by rejecting previous CAM research, but by building on that strong evidence base of what works and what is safe. The process for conventional drug and device development follows an orderly process of preclinical studies (usually on animals), phase I, phase II, and phase III studies (with the large human clinical trial phase taking place in phase III). Today, the randomized controlled trial is recognized as providing the highest level of scientific evidence. This conventional medicine approach to development is now being used to develop complementary and alternative therapies. For instance, the discovery and development of Taxol (Bristol-Meyers Squibb, New York, NY), an extract from the bark of the Pacific yew tree that is now a widely used chemotherapeutic agent, followed the conventional pathway to approval and marketing. But for most CAM products, the pathway is not so straightforward. Most CAM therapies are traditional therapies or new products that are already available to the public. Most of what is known about these therapies is of an anecdotal nature. There has been little isolation of the active principals from the crude product and there has usually been no preclinical testing. This presentation details various approaches and programs that address how to plan and conduct a rigorous clinical trial of a CAM product. And, while it takes a good deal of persistence and a strong focus on what are the critical principals in a trial, I conclude that it is possible to apply randomized controlled trials to most of the CAM modalities.

Complementary Therapies↗

PubMedDate not supplied

Physicochemical stereodescriptors of atomic chiral centers.

Physicochemical atomic stereodescriptors (PAS) were implemented that represent the chirality of an atomic chiral center on the basis of empirical physicochemical properties of the ligands. The ligands are ranked according to a specific property, and the chiral center takes an S/R-like descriptor relative to that property. The procedure is performed for a series of properties, yielding a chirality profile. Application of the PAS descriptors to the prediction of enantioselectivity in chemical reactions, from the molecular structures, is illustrated here. The relationship between the molecular structures, represented by the PAS descriptors, and the enantioselectivity was learned by neural networks, decision trees, or random forests. In a first application, a data set was employed with chiral amino alcohols that enantioselectively catalyze the addition of diethylzinc to benzaldehyde. Prediction of the major enantiomer obtained in the reaction, from the molecular structure of the catalyst, was achieved with accuracy up to 90%. The second application investigated the enantiopreference of Pseudomonas cepacia lipase (PCL) toward primary alcohols. The learned models could make correct predictions about the preferred enantiomer, from the molecular structure of the substrate, in up to 93% of the cases. These included substrates with and without O-atoms bonded to the chiral center. The properties automatically selected to build the models can give indications on the relevant factors guiding the observed chemical behavior.

Alcohols↗

PubMed2005

Prediction error estimation: a comparison of resampling methods.

MOTIVATION: In genomic studies, thousands of features are collected on relatively few samples. One of the goals of these studies is to build classifiers to predict the outcome of future observations. There are three inherent steps to this process: feature selection, model selection and prediction assessment. With a focus on prediction assessment, we compare several methods for estimating the 'true' prediction error of a prediction model in the presence of feature selection. RESULTS: For small studies where features are selected from thousands of candidates, the resubstitution and simple split-sample estimates are seriously biased. In these small samples, leave-one-out cross-validation (LOOCV), 10-fold cross-validation (CV) and the .632+ bootstrap have the smallest bias for diagonal discriminant analysis, nearest neighbor and classification trees. LOOCV and 10-fold CV have the smallest bias for linear discriminant analysis. Additionally, LOOCV, 5- and 10-fold CV, and the .632+ bootstrap have the lowest mean square error. The .632+ bootstrap is quite biased in small sample sizes with strong signal-to-noise ratios. Differences in performance among resampling methods are reduced as the number of specimens available increase. SUPPLEMENTARY INFORMATION: A complete compilation of results and R code for simulations and analyses are available in Molinaro et al. (2005) (http://linus.nci.nih.gov/brb/TechReport.htm).

Algorithms↗

PubMed1988

Facilitated transport of Mn2+ in sycamore (Acer pseudoplatanus) cells and excised maize root tips. A comparative 31P n.m.r. study in vivo.

Movement of paramagnetic Mn2+ into sycamore (Acer pseudoplatanus) cells has been indirectly examined by observing the line broadening exhibited in its 31P n.m.r. spectra. Mn2+ was observed to pass into the vacuole, while exhibiting a very minor accumulation in the cytoplasm. With time, gradual leakage of phosphate from the vacuole to the cytoplasm was observed along with an increase in glucose-6-phosphate. Anoxia did not appear to affect the relative distribution of Mn2+ in the cytoplasm and vacuole. Under hypoxic conditions restriction of almost all movement of Mn2+ across the plasmalemma as well as the tonoplast was observed. In contrast, maize root tips showed entry and complete complexation of nucleotide triphosphate by Mn2+ during hypoxia. The rate of passage of Mn2+ across the tonoplast in both sycamore and maize root cells is approximately the same. However, the rates of facilitated movement across the respective plasma membranes appear to differ. More rapid movement of Mn2+ across the plasmalemma in maize root tip cells allows a gradual build-up of metal ion in the cytoplasm prior to its diffusion across the tonoplast. Sycamore cells undergo a slower uptake of Mn2+ into their cytoplasms (comparable with the rate of diffusion through the tonoplast), so little or no observable accumulation of Mn2+ is observed in this compartment.

Adenosine Triphosphate↗

PubMedDate not supplied

Relevant in times of turmoil: WHO and public health in unstable situations.

For millions of people world-wide, surviving the pressure of extreme events is the predominant objective in daily existence. The distinction between natural and human-induced disasters is becoming more and more blurred. Some countries have known only armed conflict for the last 25 years, and their number is increasing. Recently, humanitarian sources reported 24 ongoing emergencies, each of them involving at least 300,000 people "requiring international assistance to avoid malnutrition or death". All together, including the countries still only at risk and those emerging from armed conflicts, 73 countries, i.e., almost 1.8 trillion people, were undergoing differing degrees of instability. Instability must be envisioned as a spectrum extending between "Utopia" and "Chaos". As emergencies bring forward extreme challenges to human life, medical and public health ethics make it imperative for the World Health Organisation (WHO) to be involved. As such, WHO must enhance its presence and effectiveness in its capacity as a universally accepted advocate for public health. Furthermore, as crises become more enmeshed with the legitimacy of the State, and armed conflicts become more directed against countries' social capital, they impinge more on WHO's work, and WHO must reconcile its unique responsibility in the health sector, the humanitarian imperative and the mandate to assist its primary constituents. Health can be viewed as a bridge to peace. The Organization specifically has recognised that disasters can and do affect the achievement of health and health system objectives. Within WHO, the Department of Emergency and Humanitarian Action (EHA) is the instrument for intervention in such situations. The scope of EHA is defined in terms of humanitarian action, emergency preparedness, national capacity building, and advocacy for humanitarian principles. The WHO's role is changing from ensuring a two-way flow of information on new scientific developments in public health in the ideal all-stable, all-equitable, well-resourced state, to dealing with sheer survival when the state is shattered or is part of the problem. The WHO poses itself the explicit goals to reduce avoidable loss of life, burden of disease and disability in emergencies and post-crisis transitions, and to ensure that the Humanitarian Health Assistance is in-line with international standards and local priorities and does not compromise future health development. A planning tree is presented. The World Health Organization must improve its own performance. This requires three key pre-conditions: 1) presence; 2) surge capacity; and 3) institutional support, knowledge, and competencies. Thus, in order to be effective, WHO's presence and surge capacity in emergencies must integrate the institutional knowledge, the competencies, and the managerial set-up of the Organization.

Altruism↗

PubMed2001

[Landscape structure and greenland spatial pattern in workshop district of Wuhan Iron and Steel Company].

The landscape structure and greenland spatial pattern in the workshop district of Wuhan Iron and Steel Company were investigated and analyzed on the basis of landscape ecological theory. The results showed that the main parts of the landscape structure were the artificial landscape elements such as building and concrete covering patches, highway and railway bed corridors, and industrial reservations. All of these artificial landscape elements accounted for 74.37% of patch area and 57.70% of patch dominance. In the landscape, the building and concrete covering land had the maximum percentage of patch area (56.43%) and the maximum dominance (35.59%). The special purpose greenlands had the highest fragmentation index (5.0591 ind.hm-2) and the wide-ranging distribution. The corridor density (13.78 km.km-2) was high, and the highway had more effects on landscape than the railway. All the results reflected not only the essential landscape features of industrial region, but also the rational trend of landscape structure in the workshop district of Wuhan Iron and Steel Company. In the greenland, the road greenbelts had the maximum patch number, area percentage (66.07%), and dominance (75.31%), the shelter forests being mainly composed of tree species had high patch average area (8454.45 m2) and environmental benefit, and the ornamental greenlands had abundant plant species and varied scenery. The greenland system was initially formed by four afforestation districts, using shelter forests and ornamental greenlands in large patch as a center connected by road greenbelts. It should be attached importance to the relatively high dominance of wild grasslands, the low area percentage of shelter forests and the imperfect road greenbelts to develop the uncovered lands and to improve the quality of the greenland system.

China↗

PubMed2002

Explaining human settlement patterns in a recreational lake district: Vilas County, Wisconsin, USA.

Lakeshore development in Vilas County, northern Wisconsin (USA) is heterogeneous, ranging from lakes that are surrounded by homes and commercial establishments to lakes that have no buildings on their shorelines. Development in this recreational area has increased, and since the 1960s over half of new homes have been built on the lakeshore. We examined building density around lakes in relationship to 11 variables, including in-lake, shoreline, and social characteristics. Buildings in many parts of northern Wisconsin tend to be concentrated around shorelines; in Vilas County 61% of all medium-sized buildings (our proxy for residential development) on private land were < or =100 m of a lake. The probability of development on a lake was largely related to lake surface area, with larger, more accessible lakes showing a higher probability of development. Building density along shorelines varied with travel cost, lake surface area, presence of wetlands, and extent of public land ownership. Building density was greater on larger, more accessible lakes that were surrounded by forest (as opposed to wetlands) and public lands. Gaining a more precise understanding of human settlement patterns can help direct planning and resource protection efforts to lakes most likely to experience future development.

Conservation of Natural Resources↗

PubMed2003

[Analysis of urban forest landscape pattern in Hefei].

Based on the theory and methodology of landscape ecology, the landscape pattern of the study area (17.6 km2) in the downtown of Hefei was analyzed by using the techniques of RS, GPS and GIS. The object was to provide a comprehensive method to study urban forest structure and its function in environmental improvement. The results showed that there were 5 major landscape elements, i.e., building and hard pavement surface, water, road, urban forest, and general green land in the area. The landscape matrix was building and pavement surface, occupied 73.13% of total land. Road was the typical corridor element in the city and occupied 6.89%. Green land occupied 11.44%, in which, urban forest patch occupied 9.18%. There were 408 urban forest patches, with an area of 161.16 hm2. The average area of the patch was 0.396 hm2, and the maximum area was 12 hm2. 48% of urban forest patch was identified as small scale patches with < 500 m2 of area, and only 8.6% of them was larger than 1 hm2. The number of general green land patch was 255, with an area of 39.74 hm2, which accounted for 2.26% of land area, and its average and maximum area was 0.1558 hm2 and 3.86 hm2, respectively. There were 147 water patches, with an area of 149.93 hm2, and occupied 8.54% of land, and the average and maximum area of the patch was 1.02 hm2 and 16 hm2, respectively. In the study area, both of the Shannon-Weiner landscape diversity index and evenness were low, only 0.928 and 0.576, respectively. In addition, the dominance of urban forest patch and general green land was 0.39 showing that the two landscape elements had a certain influence on the environment of the study area. The concept of interior habitat for forest was introduced in this paper, which was employed to make a scale class system of urban forest patch. The threshold area with interior habitat for urban forest patch was 9800 m2, and there was 31.69 hm2 of interior habitat of urban forest in total, which occupied 19.7% of the total area of urban forest patch. This situation was not favorable for providing more habitats to support species diversity. It's suggested that the concept of interior habitat could be employed to identify urban forest patch, and a scale system of small scale patch of urban forest-middle patch-large patch-extra large patch was build in the paper. Based on this system, the ratio of different scales of urban forest patch in the study area should be 2:2:2:3. The authors also suggested that larger pieces (1.5-3.0 hm2) of urban forest patch should be built, and more urban forests should be established in the northeastern part of the city in the future.

China↗

PubMedDate not supplied

Nurse-parent relationship building in child psychiatric units.

PROBLEM: The role of nursing with parents in child psychiatric units has undergone significant change over the years. Historically, nurses had minimal contact with parents; more recently, the nurse's work with parents has intensified. METHODS: A grounded theory study was undertaken to learn about the process of relationship building between nurses and parents on these units. Interviews and participant observation were used to collect data on 21 nurse-parent interactions. FINDINGS: Two phases in the relationship, four patterns of interactions in the working phase, and factors that influence these relationships were identified. CONCLUSIONS: The results provide the practicing nurse with information that should facilitate engaging parents.

Adult↗

PubMed2005

Persistence and developmental transition of wide seismic lines in the western Boreal Plains of Canada.

This study examined the fate of seismic lines utilized in oil and gas exploration in Canada's western Boreal Plains. It retrospectively followed the persistence, recovery and developmental transition of seismic lines established between the 1960s and the mid-1970s through to 2003. We examined lines that passed through three forest types; aspen, white spruce, and lowland black spruce. In general, the recovery rates of seismic lines to woody vegetation were low. After 35 years, 8.2% of seismic lines across all forest types had recovered to greater than 50% cover of woody vegetation. Only the upland forest types recovered; aspen and white spruce. Most seismic lines ( approximately 65% at 35 years) remained in a cleared state with a cover of low forbs. The most common transition for seismic lines was to tracked access ( approximately 20% at 35 years). Transition to other anthropogenic developments such as roads, pipelines, buildings, and timber harvest blocks was 5% after 35 years. The pulse of industrial activity initiated in the mid-1990s greatly increased the transition rate of seismic to tracked access for a short period of time. The discussion focused on natural and anthropogenic factors that hinder recovery and on the management directions that would facilitate greater recovery rates.

Alberta↗

PubMed2001

The constraint based decomposition (CBD) training architecture.

The Constraint Based Decomposition (CBD) is a constructive neural network technique that builds a three or four layer network, has guaranteed convergence and can deal with binary, n-ary, class labeled and real-value problems. CBD is shown to be able to solve complicated problems in a simple, fast and reliable manner. The technique is further enhanced by two modifications (locking detection and redundancy elimination) which address the training speed and the efficiency of the internal representation built by the network. The redundancy elimination aims at building more compact architectures while the locking detection aims at improving the training speed. The computational cost of the redundancy elimination is negligible and this enhancement can be used for any problem. However, the computational cost of the locking detection is exponential in the number of dimensions and should only be used in low dimensional spaces. The experimental results show the performance of the algorithm presented in a series of classical benchmark problems including the 2-spiral problem and the Iris, Wine, Glass, Lenses, Ionosphere, Lung cancer, Pima Indians, Bupa, TicTacToe, Balance and Zoo data sets from the UCI machine learning repository. CBD's generalization accuracy is compared with that of C4.5, C4.5 with rules, incremental decision trees, oblique classifiers, linear machine decision trees, CN2, learning vector quantization (LVQ), backpropagation, nearest neighbor, Q* and radial basis functions (RBFs). CBD provides the second best average accuracy on the problems tested as well as the best reliability (the lowest standard deviation).

Algorithms↗

PubMed2001

Substitution rates in alpha-helical transmembrane proteins.

It has been shown previously that some membrane proteins have a conserved core of amino acid residues. This idea not only serves to orient helices during model building exercises but may also provide insight into the structural role of residues mediating helix-helix interactions. Using experimentally determined high-resolution structures of alpha-helical transmembrane proteins we show that, of the residues within the hydrophobic transmembrane spans, the residues at lipid and subunit interfaces are more evolutionarily variable than those within the lipid-inaccessible core of a polypeptide's transmembrane domain. This supports the idea that helix-helix interactions within the same polypeptide chain and those at the interface between different polypeptide chains may arise in distinct ways. To show this, we use a new method to estimate the substitution rate of an amino acid residue given an alignment and phylogenetic tree of closely related proteins. This method gives better sensitivity in the otherwise-conserved transmembrane domains than a conventional similarity analysis and is relatively insensitive to the sequences used.

Amino Acids↗

PubMed1989

Dynamic behavioural models and contraceptive choice.

Dynamic models of contraceptive use fill a theoretical gap. They bring behavioural content to the mathematically elegant Markov models of family building. They meet the criterion that Bulatao (1989) advances that method use, discontinuation and switching be considered not in isolation, but with reference to individual reproductive goals. Dynamic models help to link the literature on method choice with the literature on method effectiveness. These theoretical advantages are, at present, counter-balanced by empirical limitations. This article explores the theoretical and empirical underpinnings of dynamic contraceptive choice models.

Abortion, Legal↗

PubMed2002

Temporal change in genetic structure and effective population size in steelhead trout (Oncorhynchus mykiss).

There is a wealth of published molecular population genetic studies, however, most do not include historic samples and thus implicitly assume temporal genetic stability. We tested for changes in genetic diversity and structure in three populations of steelhead trout (Oncorhynchus mykiss) from a northern British Columbia watershed using seven microsatellite loci over 40 years. We found little change in genetic diversity (mean allele numbers and observed and expected heterozygosity), despite large variation in the estimated numbers of steelhead returning to the watershed over the same time period. However, the temporal stability in genetic diversity is not reflected in population structure, which appears to be high among populations, yet significantly variable over time. The neighbour-joining tree showed that, overall, two of the populations (Zymoetz and Kispiox) clustered separately from the third (Babine); a finding which was not consistent with their geographical separation. The clustering pattern was also not temporally consistent. We used the temporal method to estimate the effective number of breeders (Nb ) for the three populations; our values (Nb = 17-102) were low for the large and presumed vigorous populations of steelhead trout sampled. The low Nb values were also not consistent with the generally high genetic diversity estimates, suggesting the possibility of intermittent gene flow among the three populations. The use of temporal analyses in population genetic samples should be a priority; first, to verify observed patterns in contemporary data, and second, to build a dataset of temporal analyses to allow generalizations to be made concerning temporal genetic stability and effective population size in natural populations.

Animals↗

PubMed2004

Silver cages with encapsulated acetylenediide as building blocks for hydrothermal synthesis of supramolecular complexes with n-cyanopyridine and pyridine-n-carboxamide (n=3, 4).

New silver(i) double salts (Ag(2)C(2))(AgCF(3)CO(2))(8)(3-pyCONH(2))(2)(H(2)O)(4) (1), [(Ag(2)C(2))(AgCF(3)CO(2))(4)(4-pyCONH(2))(H(2)O)].H(2)O (2), (Ag(2)C(2))(AgCF(3)CO(2))(6)(3-pyCONH(2))(4) (3), (Ag(2)C(2))(AgCF(3)CO(2))(6)(3-pyCN)(2) (4) and (Ag(2)C(2))(AgCF(3)CO(2))(4)(4-pyCN)(2) (5) (n-pyCONH(2) is pyridine-n-carboxamide, n-pyCN is n-cyanopyridine; n=3, 4) have been synthesized by the hydrothermal method. All five compounds contain polyhedral silver(i) cages each encapsulating a C(2)(2-) dianion. Compounds 1, 3 ,4 and 5 exhibit three-dimensional structures, whereas compound 2 is a two-dimensional network. The structure of 1 is constructed from the linkage of a branched-tree architecture via hydrogen bonds. Unlike 4 and 5, which involve the connection of n-cyanopyridine (n=3, 4) with silver columns, 3 results from the linkage of discrete silver cages via pyridine-3-carboxamide.

Journal Article↗