Leeches are fascinating animals. They can be found everywhere, from ponds to streams, from polar seas to desert oases. Many of the about 300 species of leeches feed on small invertebrates, only some species are parasitic blood suckers. The leech’s spittle does not only contain enzymes which prevent blood clotting but also an anesthetic. So the host is not aware of the attack by the blade-like jaws or secreted enzymes that digest a hole through the skin. It is no accident that the most famous leech species is called Hirudo medicinalis. Leeches have a long tradition in medical treatment. Before using it for treatment, the leech needs to be washed and the gut content needs to be squeezed, because leeches just “attack” when their gut is empty. Interestingly, H.medicinalis does not produce any gut enzymes. Symbiotic bacteria, principally Aeromonas hydrophila, which are living in the leech’s gut, carry out the digestion. The medical treatment with leeches is a sort of improvement of the much older tradition of bloodletting, which origins are suspected to go back as far as the Stone Age. The advantage of leeches is that it is less painful and easier to use for body parts which are hard/dangerous to access with blades like eyes and rectum. This usage of leeches in medicine in mind, it seems logical that, in the past, the word “leech” had a second meaning as medical practitioner. However, as Robert N. Mory et al. (2000) pointed out, this is an example of folk etymology: a “type of linguistic development, in which an apparently logical connection is used to explain (or is understood as) the development of one meaning from another”. In reality, "leech" and "leech", the worm and the physician, have two different origins. Both are based on the Old English word “leace”. However, while the worm “leech” came from the Middle Dutch lieke, the physician “leech” has its origin in Germanic languages including Old Frisian letza, Old Saxon laki, and Old High German lakki. So, even if leeches and leeches worked together in the past, the origins of their names are not connected. Today the word “leech” for physician is outdated. Today, “leech” is used to describe people which download from file-sharing sites without uploading anything. There the logical connection to the worm “leech” is obvious. Both are parasites: taking without giving something back. "The leech and the physician: biology, etymology, and medical practice with Hirudinea medicinalis."
Robert N. Mory, David Mindell, and David A. Bloom World journal of surgery 24.7 (2000): 878-883.
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The todays paper reads a little bit like an ad for alternative medicine. It is about “the clinical practices and perceptions of professional herbalists providing patient care concurrently with conventional medical practice in Australia.” (Mavourneen Casey, et al. , 2007). Back then, in 2007, “a total of 1.9 million consultations for herbal medicine and naturopathy have been reported to occur annually in Australia.” I first thought that this isn’t much but this was due to a lack of my geographic knowledge. In the surprisingly small population of Australia of 23 million people (compared to Germany with 80million people), 1.9 million is around 8%. Herbal medicine comprises oral medication of strong pharmacologically active compounds. In a former "paper of the day" I wrote about the health supporting effect of the traditional Maori diet which included e.g. plants with cancer suppressing effects. Also “common pharmaceutical medications such as aspirin, morphine, codeine, atropine and digoxin were originally derived from herbal medicines.” So herbal medicine is interesting, especially its position to conventional medicine. Therefore, Casey et al. sent a postal survey “to all full members of the only national association of Western herbal medicine practitioners in Australia, the National Herbalists’ Association of Australia (NHAA).” The questions covered educational qualification and years of working experience of the herbalists as well as the methods/workflow of their therapy and the interaction with conventional medicine. Moreover, the herbalists were asked about their perceptions of their role in patient care, including medical diagnosis and the understanding of herbal therapy/pharmaceutical drug interactions. The results of the survey show a tight connection between herbal and conventional medicine. On the one hand, the number of herbalists with university qualifications increases which supports the trend of the integration of orthodox medical knowledge into herbal practices like blood test, lever function test and hormone profiles for treatment decision. On the other hand, the patients themselves tend to seek treatment in both medicines parallel. “Most patients who visit professional herbalists tend to seek care for chronic conditions, already have a medical diagnosis, and continue with concurrent conventional medical treatment.” This increases the risk of drug interactions. Therefore, in order to guarantee the safety of the patients, a study of the active compounds of the herbal medicine is important as well as a closer collaboration and cooperation between the medical communities. “An understanding of the ways in which herbalists practice and prescribe may be invaluable in the debate about the safety and efficacy of herbal medicines and may help the planning of reliable and valid research in the future.“ "An examination of the clinical practices and perceptions of professional herbalists providing patient care concurrently with conventional medical practice in Australia"
Mavourneen Casey, Jon Adams, and David Sibbritt Complementary therapies in medicine 16.4 (2008): 228-232 Deleterious oral habits? That term summarizes all habits which are destructive for the teeth and supporting structures like lip/thumb sucking, lip/nail biting and buxism (teeth grinding). Based on previous studies, it its hypothesized that deleterious oral habits are connected to mouth breathing and the time interval a baby is breast fed: “Babies fed preferably with mother’s milk for a short interval or not breastfed at all have increased probability of developing mouth breathing and deleterious oral habits than babies breastfed for at least six months of age.” So does breast feeding prevent deleterious oral habits? In 2005, Trawitzki et al. published a study were they tested this hypothesis. They tested 62 children (3-6 years old) for their breathing and oral habits and sorted them in groups of mouth breathers and nose breathers. Statistic analysis of the feeding history of the study revealed that 100% of the nose breathing children were fed preferably with mother’s milk for intervals higher than three months. However, there were also breast fed children among the mouth breathers (37.5%). Moreover, the study showed that the feeding history of the children showed no significant difference in feeding by milk bottles between mouth and nose breathing children. Significant differences occurred in the presence of deleterious oral habits between mouth and nose breathers. Suction and biting habits were more common in mouth breathers compared to nose breathers. But what do we learn from these results? Does breast feeding prevent deleterious oral habits? No.
Breast-feeding and deleterious oral habits in mouth and nose breathers
L. V. V. Trawitzki et al. Brazilian journal of otorhinolaryngology 71.6 (2005): 747-751 Maybe it is not clear how I choose my random paper of the day. However, I am quite sure that everybody will understand why I chose the paper of W. Michael Dunne, Jr. (2002). How could I not choose a paper with such a great title: “Bacterial Adhesion: Seen Any Good Biofilms Lately?” I have to admit, I haven’t seen any biofilms lately. Or more correct: I was not aware of any biofilms around me lately, but I am sure there have been some as they can be found on a variety of “wet” surfaces like “contact lenses, ship hulls, dairy and petroleum pipelines, rocks in streams, and all varieties of biomedical implants and transcutaneous devices”. Biofilms are the results of a combination of aquatic bacterial populations, a surface and glycocalyx. The latter is the “slime” surrounding the bacteria and is mainly made of polysaccharides (sugars). The biofilm structure differs between the bacteria species. However, it seems true for all species that bacteria in biofilms are harder to destroy with antibiotics as their planktonic (solved) form. The “slime” of the biofilm helps to gather essential minerals and nutrients from the surrounding and protects the bacteria from enemies like antibiotics, bacteriophages and predators. Not all bacteria can bind on all surfaces. If a bacteria is near a surface, the net sum of different forces like e.g. electrostatic and hydrophobic interactions decides if the bacteria can dock on or not. These forces differ between different bacteria species. For example, in contrast to the most bacteria, which are negatively charged, Stenotrophomonas maltophilia is posetively charged at physiological pH and can therefore bind on negatively charged surfaces like Teflon where the other bacteria are repelled. The adhesion process is strengthened by production of adhesin and/or receptor-specific ligands on the surface or on structures extending from the cell surface, such as pili, fimbriae, and fibrillae. The method can differ in the same bacteria depending on the surface: “In the case of Vibrio cholerae El Tor, a toxin-coregulated pilus is used […] during the process of human infection, whereas […] adhesin [is] used to anchor to abiotic surfaces in an aquatic environment.“ Adhesion of a bacteria species can enhance the adhesion of another bacteria species by forming a heterogeneous biofilm. This makes it hard/impossible to prevent biofilms on certain surfaces even though they are known to cause infections, biofouling and corrosion. However, biofilms can also be beneficial for nitrogen fixation and bioremediation of wastewater. Summing up: Biofilms are universal and as Dunne wrote: “One has only to experience the process of cleaning a J trap in a clogged sink drain to fully appreciate the potential magnitude of bacterial biofilms and the process of biofouling on a small scale.” "Bacterial adhesion: seen any good biofilms lately?"
W. Michael Dunne Jr. Clinical microbiology reviews 15.2 (2002): 155-166. Which factors determine micro-arthropods (like mites and springtails) abundance and diversity in the soil? Stef Bokhorst et al. addressed this question in a paper which was published in 2014. They analyzed the effect of plant removals in pine forest sectors in Sweden which differ in their age (time scince last forest fire) on the micro-arthropod community living in the soil. With increasing forest age, the soil fertility and amount of fast growing plant species decreases while the humus layer and amount of slow growing plant species increases. The forest sectors in this experiments were between 44 and 364 years old. In each sector, Bokhorst et al. did the same two experiments: I) removal of feather mosses and dwarf shrubs as the two main understory functional groups (understory = plant life on the ground of the forest) and II) removal of specific dwarf shrub species. While feather mosses are thought to have a large effect on the soil ecosystem because of its temperature and humidity regulation effects, dwarf shrubs (something between herb and bush) influence the soil with their litter production. However, as leaves are also produced by trees, it doesn’t wonder that the removal of moss had larger influence on the abundance of micro-arthropods as the removal of dwarf shrubs (in experiment I). All in all, the dwarf shrubs species had just minor effects on the micro-arthropods abundance and diversity, independent of their litter quality (experiment II). So mites and springtails care mainly about moss. But what about the age of the forest which affects the properties of the soil? Interestingly, only a few groups of micro-arthropods were affected by the forrest age. The others don’t care. And this is already the summary of this article: Plant removal, forest age? If you don’t touch the moss, the micro-arthropods don’t care so much what you are doing there on the surface. "Impact of understory mosses and dwarf shrubs on soil micro-arthropods in a boreal forest chronosequence."
Stef Bokhorst, et al. Plant and soil 379.1-2 (2014): 121-133. Whosoever has tried to program something at least once knows that it can be sometimes quite hard to write codes for task which are easy for every human being. One example is NERC (Named Entity Recognition and Classification). The task sounds simple: scanning a text for mentions of certain categories like person/company names, temporal expressions, locations, etc. Using this example sentence: One of the first papers about NERC was published in 1991. The author, Lisa F, Rau described a system based on heuristics and handcrafted rules which was aimed to “extract and recognize [company] names”. Since then, NERC became more and more prominent. Today there are a lot of papers about NERC for different categories and text genres using different algorithms and methods. Handcrafted rules are replaced by machine learning algorithms and different features like e.g. dictionaries, analysing word structures (e.g. capital letters and numbers) and text structures (e.g. newspaper articles beginning with location and date) improve the NERC performance. In summary: Extracting and classifying information in texts, which seems easy for humans, engaged computer scientists for years and it will do so also for the next years. At least texts are not the only media for information. There are also other media like videos and speech which contain information which can be extracted and classified. Review about NERC from 1991 to 2006:
"A survey of named entity recognition and classification" David Nadeau and Satoshi Sekine Lingvisticae Investigationes 30.1 (2007): 3-26. |
IdeaI love to increase my general science knowledge by reading papers from different fields of science. Here I share some of them. Archiv
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