Bacteriological and epidemiological studies of streptococcal infections: with particular reference to epidemiological analyses by serological typing of haemolytic streptococci

(1) PREPARATION OF TYPE -SPECIFIC SERA: (a) Vaccine was prepared from Griffith's thirty types of haemolytic streptococci. (b) Rabbits were injected and test-bleedings made at various times to estimate the titre of the serum. (c) The method of preparing type- specific agglutinating sera was described, and particular mention of cross -reactions was made.(2) THE TYPING OF HAEMOLYTIC STREPTOCOCCI: (a) A series of investigations were carried out t determine the most suitable media for growing homogeneous suspensions of haemolytic streptococci. The method of incubation best suited was described. (b) A description of the slide -agglutination method of typing used throughout this work was given.CLINICO- BACTERIOLOGICAL INVESTIGATIONS OF SCARLET FEVER CASES. (3) The procedure adopted in swabbing patients was intimated.(4) There followed a description of the method adopted for storing haemolytic streptococci "in vacuo".(5) Statistical records for the period September 1937 to January 1939 were drawn up and included the total number of admissions of scarlet fever cases to the City Fever Hospital, the total number swabbed, the total number of complications, and the total number of complications swabbed.(6) Monthly graphs and tables indicating the result of typing the above cases was given.(7) The monthly percentage increase and decrease of the various types of haemolytic streptococci were recorded.(8) An investigation was carried out to show whether any difference in the types of haemolytic streptococci found in the throats and noses of scarlet fever cases existed.(9) The next investigation was carried out to determine whether there occurred more than one type of haemolytic streptococcus in the throat swabs of patients on admission to hospital.(10) This investigation was an attempt to ascertain whether any cases, which had been in the wards for some time, had more than one type of haemolytic streptococci in their throats.(11) The results of the last investigation were compared with those found during the first day complications became manifest.(12) Daily swabs were taken in a single ward over a period of 23 days and all the patients typed. All cross- infections were noted.(13) The same investigation was carried out over a period of 46 days.(14) 384 cases showing complications were investigated. The haemolytic streptococci present on admission and those responsible for the complications were noted. Correlations between types and lesions, etc., were recorded.(1 5) An investigation was undertaken showing the decrease of haemolytic streptococci in the throats of patients during their stay in hospital.(16) During the month of May, 1938, twenty cases of scarlet fever were typed and the same done to fifteen cases showing complications. The results were investigated.(17) A statistical record of scarlet fever cases occurring in the City of Edinburgh from the 1/9/37 to 31/12/38 was drawn up.(18) The number of patients per month from the various schools and institutions in Edinburgh was calculated and recorded in tables.A graph comparing the number of school children with all other cases is given.(19) The types of haemolytic streptococci found in school cases and other patients were noted and certain correlations observed.(20) An attempt was made to show that there existed a relationship of types of haemolytic streptococci found in the patients from individual schools.(21) 54 cases of puerperal fever were investigated bacteriologically.(22) Similarly 40 cases of erysipelas were investigated.(23) This was also done with 10 cases of otitis media or mastoiditis, and(24) with 60 cases of tonsillitis.(25) A miscellaneous group of diseases sent into the City Fever Hospital as scarlet fever cases was examined for haemolytic streptococci (42 patients).(26) Eight positive haemolytic streptococci ;swabs from the Third Year Medical Students were examined. This was carried out during a time when "coughs, and colds" were common.(27) 32 cases of respiratory diseases occurring in a rural area were investigated for the presence of haemolytic streptococci. These were typed and compared with the urban strains.(28) The next investigation was carried out to ascertain the presence of haemolytic streptococci in normal throats and to find what correlation there existed between the types found and the various streptococcal infections. The normal throats were those of: (a) 40 nurses from the City Fever Hospital. (b) The positive swabs from a number of nurses from the Western General Hospital, (c) Six resident doctors in the City Fever Hospital. (d) Ten strains from the Third Year Medical students were typed. The period was one when only a few "coughs and colds" were about. (e) 16 families, from whom cases of scarlet fever had been sent to hospital, were visited and all members swabbed, with a view to determining the presence of haemolytic streptococci and observing any correlations. 260 (f) This investigation was carried out upon my own' person to estimate the number of haemolytic streptococci present in throat and nose before and after contact with scarlet fever patients.(29) The presence of haemolytic streptococci on toys and food in the scarlet fever wards was investigated.(30) A similar investigation was carried out on the handkerchiefs of patients.AIR -CONTAMINATION WITH HAEMOLYTIC STREPTOCOCCI IN THE CITY FEVER HOSPITAL WARDS.(31) (a) A research was made to determine the incidence of haemolytic streptococci in the air of fever wards. (b) A similar investigation was done in a puerperal ward; and in (c) an erysipelas ward; and in (d) a diphtheria; and in (e) a measles ward. (f) The first investigation (a) was repeated in a ward with a high complication rate, and repeated in another with a low complication rate. The results were correlated.(32) Air contamination with haemolytic streptococci in the Ear, Nose and Throat Department of the Edinburgh Royal Infirmary was investigated.(33) The next investigation was to determine the presence of haemolytic streptococci and their types in picture houses, buses, trams, shops and open places.(34) An attempt was made to correlate the types found in scarlet fever with those of all other streptococcal infections.(35) A research into the problem of air-borne infection was carried out. The object of this investigation was to determine what effects variations of ventilation, and wet and dry sweeping have on the number of organisms in the air.B. prodigiosus was the organism used in this investigation and was sprayed by means of an atomiser.(36) Cross-contamination in the cubicles of the City Fever Hospital was investigated.(37) The final investigation was an attempt to type those strains of haemolytic streptococci which were either too granular or failed to type by ordinaryj methods

3-methylhistidine as an Indicator for Protein Beakdown: An Experimental Model in Male Capra hircu

The role of the amino acid 3-methylhistidine as an indicator of protein breakdown and weight loss is  often suggested. Despite existing information for other animal species, little is known about the actual  levels of 3-methyhistidine in the serum of less studied domestic species such as the goat. We have  evaluated the 3-methyhistidine serum concentrations in young Boer goat bucks subjected to two distinct  feeding regimens: winter-grass hay with or without supplementation. Non-supplemented animals had a  negative nitrogen balance and experienced weight loss throughout the experiment and significantly higher  concentrations of 3-methyhistidine than supplemented animals that had a slight increase in live weight.  This amino acid can be considered a valid indicator of protein breakdown and weight decrease in male  goats. Serum 3-methylhistidine concentrations in adequately fed male goats were similar throughout the  assay (20-40 μmol/l) whereas in weight-losing animals, concentrations of up to 170μmol/l can be expected.

Entropic effects on the Size Evolution of Cluster Structure

We show that the vibrational entropy can play a crucial role in determining the equilibrium structure of clusters by constructing structural phase diagrams showing how the structure depends upon both size and temperature. These phase diagrams are obtained for example rare gas and metal clusters.Comment: 5 pages, 3 figure

Combinatorial Selection Among Geometrical Isomers of Discrete Long-Carbon-Chain Naphthalenediimides Induces Local Order at the Liquid/Solid Interface

We report two families of naphthalenediimides (NDIs) symmetrically functionalized with discrete carbon chains comprising up to 55 carbon atoms (Cn-NDI-Cn, n = 39, 44, 50, and 55) and their self-assembly at the 1-phenyloctane/highly oriented pyrolytic graphite interface (1-PO/HOPG interface). The compounds differ by the presence or absence of two or three internal double bonds in the carbon chains (unsaturated and saturated Cn-NDI-Cn, respectively). Combinatorial distributions of geometrical isomers displaying either the E- or Z-configuration at each double bond are obtained for the unsaturated compounds. Analysis of the self-assembled monolayers of equally long unsaturated and saturated Cn-NDI-Cn by scanning tunneling microscopy (STM) reveal that all Cn-NDI-Cn tend to form lamellar systems featuring alternating areas of aromatic cores and carbon chains. Extended chain lengths are found to significantly increase disorder in the self-assembled monolayers due to misalignments and enhanced strength of interchain interactions. This phenomenon is antagonized by the local order-inducing effect of the internal double bonds: unsaturated Cn-NDI-Cn give qualitatively more ordered self-assembled monolayers compared to their saturated counterparts. The use of combinatorial distributions of unsaturated Cn-NDI-Cn geometrical isomers does not represent a limitation to achieve local order in the self-assembled monolayers. The self-assembly process operates a combinatorial search and selects the geometrical isomer(s) affording the most thermodynamically stable pattern, highlighting the adaptive character of the system. Finally, the antagonistic interplay between the extended carbon chain lengths and the presence of internal double bonds brings to the discovery of the lamellar "phase C" morphology for unsaturated Cn-NDI-Cn with n ≥ 50

Essential medicine selection during the COVID-19 pandemic: Enabling access in uncharted territory

The COVID-19 pandemic requires urgent decisions regarding treatment policy in the face of rapidly evolving evidence. In response, the South African Essential Medicines List Committee established a subcommittee to systematically review and appraise emerging evidence, within very short timelines, in order to inform the National Department of Health COVID-19 treatment guidelines. To date, the subcommittee has reviewed 14 potential treatments, and made recommendations based on local context, feasibility, resource requirements and equity. Here we describe the rapid review and evidence-to-decision process, using remdesivir and dexamethasone as examples. Our experience is that conducting rapid reviews is a practical and efficient way to address medicine policy questions under pandemic conditions

Seed systems smallholder farmers use

Seed can be an important entry point for promoting productivity, nutrition and resilience among smallholder farmers. While investments have primarily focused on strengthening the formal sector, this article documents the degree to which the informal sector remains the core for seed acquisition, especially in Africa. Conclusions drawn from a uniquely comprehensive data set, 9660 observations across six countries and covering 40 crops, show that farmers access 90.2 % of their seed from informal systems with 50.9 % of that deriving from local markets. Further, 55 % of seed is paid for by cash, indicating that smallholders are already making important investments in this arena. Targeted interventions are proposed for rendering formal and informal seed sector more smallholder-responsive and for scaling up positive impacts

Noncrystalline structures of ultrathin unsupported nanowires

Computer simulations suggest that ultrathin metal wires should develop exotic, non-crystalline stable atomic structures, once their diameter decreases below a critical size of the order of a few atomic spacings. The new structures, whose details depend upon the material and the wire thickness, may be dominated by icosahedral packings. Helical, spiral-structured wires with multi-atom pitches are also predicted. The phenomenon, analogous to the appearance of icosahedral and other non-crystalline shapes in small clusters, can be rationalized in terms of surface energy anisotropy and optimal packing

Non-thermal transitions in a model inspired by moral decisions

This work introduces a model in which agents of a network act upon one another according to three different kinds of moral decisions. These decisions are based on an increasing level of sophistication in the empathy capacity of the agent, a hierarchy which we name Piaget's ladder. The decision strategy of the agents is non-rational, in the sense they are arbitrarily fixed, and the model presents quenched disorder given by the distribution of its defining parameters. An analytical solution for this model is obtained in the large system limit as well as a leading order correction for finite-size systems which shows that typical realisations of the model develop a phase structure with both continuous and discontinuous non-thermal transitions

Cooperation in wild Barbary macaques: factors affecting free partner choice

A key aspect of cooperation is partner choice: choosing the best available partner improves the chances of a successful cooperative interaction and decreases the likelihood of being exploited. However, in studies on cooperation subjects are rarely allowed to freely choose their partners. Group-living animals live in a complex social environment where they can choose among several social partners differing in, for example, sex, age, temperament, or dominance status. Our study investigated whether wild Barbary macaques succeed to cooperate using an experimental apparatus, and whether individual and social factors affect their choice of partners and the degree of cooperation. We used the string pulling task that requires two monkeys to manipulate simultaneously a rope in order to receive a food reward. The monkeys were free to interact with the apparatus or not and to choose their partner. The results showed that Barbary macaques are able to pair up with a partner to cooperate using the apparatus. High level of tolerance between monkeys was necessary for the initiation of successful cooperation, while strong social bond positively affected the maintenance of cooperative interactions. Dominance status, sex, age, and temperament of the subjects also affected their choice and performance. These factors thus need to be taken into account in cooperative experiment on animals. Tolerance between social partners is likely to be a prerequisite for the evolution of cooperation