32 research outputs found
On the oxidation of organic matter in marine sediments by bacteria
The question as to whether the organic matter in the sea bottom is inert or is available as a nutrient for the bottom fauna and bottom-inhabiting bacteria is a problem of special interest in the cycle of life in the sea. A number of marine animals, making up the benthos or the bottom fauna, must depend upon this organic matter for their nutrition while the sea bottom also harbors an extensive bacterial population which require the energy to be derived from various nutrient elements for cell synthesis and respiration
Editor\u27s Commentary: On the oxidation of organic matter in marine sediments by bacteria
Selman Waksman is best known for his work on natural antibiotics, for which he originated the term and received a Nobel Prize. However, he and co-workers also extensively investigated soil microbes and their interactions with biogeochemical processes and elemental cycling..
Classic Article: On the oxidation of organic matter in marine sediments by bacteria
The question as to whether the organic matter in the sea bottom is inert or is available as a nutrient for the bottom fauna and bottom-inhabiting bacteria is a problem of special interest in the cycle of life in the sea. A number of marine animals, making up the benthos or the bottom fauna, must depend upon this organic matter for their nutrition while the sea bottom also harbors an extensive bacterial population which require the energy to be derived from various nutrient elements for cell synthesis and respiration..
Epidemiology of bloodstream infections in a multicenter retrospective cohort of liver transplant recipients
Although some studies have examined the epidemiology of bloodstream infections after liver transplantation, they were based in single centers and did not identify bloodstream infections treated in other hospitals. METHODS: We retrospectively examined a cohort of 7912 adult liver transplant recipients from 24 transplant centers using 2004 to 2012 International Classification of Diseases, Ninth Revision, Clinical Modification billing data from 3 State Inpatient Databases, and identified bloodstream infections, inpatient death, and cumulative 1-year hospital costs. Multilevel Cox regression analyses were used to determine factors associated with bloodstream infections and death. RESULTS: Bloodstream infections were identified in 29% (n = 2326) of liver transplant recipients, with a range of 19% to 40% across transplant centers. Only 63% of bloodstream infections occurring more than 100 days posttransplant were identified at the original transplant center. Bloodstream infections were associated with posttransplant laparotomy (adjusted hazard ratio [aHR], 1.52), prior liver transplant (aHR, 1.42), increasing age (aHR, 1.07/decade), and some comorbidities. Death was associated with bloodstream infections with and without septic shock (aHR, 10.96 and 3.71, respectively), transplant failure or rejection (aHR, 1.41), posttransplant laparotomy (aHR, 1.40), prior solid-organ transplant (aHR, 1.48), increasing age (aHR, 1.15/decade), and hepatitis C cirrhosis (aHR, 1.20). The risk of bloodstream infections and death varied across transplant centers. Median 1-year cumulative hospital costs were higher for patients who developed bloodstream infections within 1 year of transplant compared with patients who were bloodstream infection-free (US 111 313; P < 0.001). CONCLUSIONS: Bloodstream infections are common and costly complications after liver transplantation that are associated with a markedly increased risk of death. The incidence and risk of developing bloodstream infections may vary across transplant centers
Miscarriage and stillbirth following maternal Zika virus infection in nonhuman primates.
Zika virus (ZIKV) infection is associated with congenital defects and pregnancy loss. Here, we found that 26% of nonhuman primates infected with Asian/American ZIKV in early gestation experienced fetal demise later in pregnancy despite showing few clinical signs of infection. Pregnancy loss due to asymptomatic ZIKV infection may therefore be a common but under-recognized adverse outcome related to maternal ZIKV infection
Pressed for Space: The Effects of Justification and the Printing Process on Fifteenth-Century Orthography
There is a long-held belief that, prior to the standardisation of written English, printers altered spellings to justify their type. I investigate this claim through an analysis of spelling changes in William Caxton’s two editions of the Canterbury Tales—by examining text within one book, written by one author, and set by one compositor, the only difference between the sections of verse and the sections of prose should be the requirement for justification within the latter. Were the compositors altering spellings to justify their type, we would expect to see a greater number of altered spellings in the prose sections of text. This is not what the results of this study show—instead there is no statistically significant difference between the frequency of spelling changes in justified and non-justified text. However, there is a significantly higher number of abbreviations introduced into the justified text. These results suggest that the compositor of Caxton’s second edition Canterbury Tales did not change spellings to justify his type
Undocumented Worker Employment and Firm Survivability
Do firms employing undocumented workers have a competitive advantage? Using administrative data from the state of Georgia, this paper investigates the incidence of undocumented worker employment across firms and how it affects firm survival. Firms are found to engage in herding behavior, being more likely to employ undocumented workers if competitors do. Rivals' undocumented employment harms firms' ability to survive while firms' own undocumented employment strongly enhances their survival prospects. This finding suggests that firms enjoy cost savings from employing lower-paid undocumented at workers wages less than their marginal revenue product. The herding behavior and competitive effects are found to be much weaker in geographically broad product markets, where firms have the option to shift labor-intensive production out of state or abroad
Radial shortening following a fracture of the proximal radius: Degree of shortening and short-term outcome in 22 proximal radial fractures
Background and purpose: The Essex-Lopresti lesion is thought to be rare, with a varying degree of disruption to forearm stability probable. We describe the range of radial shortening that occurs following a fracture of the proximal radius, as well as the short-term outcome in these patients. Patients and methods Over an 18-month period, we prospectively assessed all patients with a radiographically confirmed proximal radial fracture. Patients noted to have ipsilateral wrist pain at initial presentation underwent bilateral radiography to determine whether there was disruption of the distal radio-ulnar joint suggestive of an Essex-Lopresti lesion. Outcome was assessed after a mean of 6 (1.5-12) months using clinical and radiographic results, including the Mayo elbow score (MES) and the short musculoskeletal function assessment (SMFA) questionnaire. One patient with a Mason type-I fracture was lost to follow-up after initial presentation. Results 60 patients had ipsilateral wrist pain at the initial assessment of 237 proximal radial fractures. Radial shortening of ≥ 2mm (range: 2-4mm) was seen in 22 patients (mean age 48 (19-79) years, 16 females). The most frequent mechanism of injury was a fall from standing height (10/22). 21 fractures were classified as being Mason type-I or type-II, all of which were managed nonoperatively. One Mason type-III fracture underwent acute radial head replacement. Functional outcome was assessed in 21 patients. We found an excellent or good MES in 18 of the 20 patients with a Mason type-I or type-II injury. Interpretation The incidence of the Essex-Lopresti lesion type is possibly under-reported as there is a spectrum of injuries, and subtle disruptions often go unidentified. A full assessment of all patients with a proximal radial fracture is required in order to identify these injuries, and the index of suspicion is raised as the complexity of the fracture increases.</p
Evidence on the Specificity of Hexosidases: A Comparison of the Activity of Escherichia coli and Escherichia communior
The ability of lower plants to utilize carbohydrates, which has been useful to bacteriologists in studies on the systematic rela-tionships of bacteria, now finds a place in the work of those bio-chemists who are interested in the structure of various fermentable sugars. A considerable literature has grown up around the efforts of Weidenhagen to utilize biological data in substantiating his classification of enzymes, since confusing results have been ob-tained; and in one instance two reputable workers in different laboratories who used the same material reported opposing con-clusions (Karstr6m, 1930-31; Weidenhagen, 1930). Working with yeast, Weidenhagen has obtained evidence for his theory that an a-glucosidase will hydrolyse all a-glucoside linkages and therefore both maltose and sucrose. Karstr6m's studies (1930) have brought to the attention of biochemists the well known fact that Escherichia coli can ferment maltose but not sucrose, which is an evidence of the specificity of hexosidases, and his results have been confirmed by Virtanen (1931), Myrbach (1931), and Tauber and Kleiner (1933). While trying to repro-duce identical enzyme preparations for our colleagues we were led on to work which throws some light on the causes of varying results. Since it seems agreed that the optimum pH for sucrase and maltase action is in the neighborhood of 7.0, an aseptic technique is essential if fermentation due to contaminating organisms is t