Sex Difference in Contusion of the Medial Femoral Condyle Rim-Association with MRI Occult Meniscal Tears in the ACL Deficient Knee

BackgroundMeniscal tears, specifically lateral meniscal tears, have a larger than expected un-derdiagnosis rate in the presence of an ACL tear. The purpose of our study was to search for an MRI bone contusion pattern associated with MRI occult meniscal tears in patients with an ACL tear, specifically a contusion of the rim of the medial femoral condyle (RMFC). Our hypothesis was that there would be a significant association between RMFC contusions and MRI occult meniscal tears in patients with an ACL tear. We also searched for a difference between sexes with respect to the presence of the RMFC contusion in the setting of an occult meniscal tear. We also categorized the type, size, and location of these occult meniscal tears in the setting of an ACL tear.Methods This was a retrospective study that examined characteristics of occult meniscal tears and their association with a RMFC bone contusion. IRB approval was obtained. The date range of the study was June 2009 through December 2015. 6392 consecutive knee MRI reports in patients with an ACL deficient knee were reviewed. The study group included 22 patients with MRI occult meniscal tears, the control group included 110 patients. Relevant statistical values were calculated.ResultsThe most common type of occult meniscal tears were small radial and small longitudinal tears of the lateral meniscus. Occult meniscal tears were associated with an RMFC contusion in the study group (p=0.0457), particularly in males (p = 0.0003). In males with a torn ACL, the sensitivity of an RMFC contusion for an occult meniscal tear was 80%.ConclusionIn males with an ACL tear, there was a significant association between a contusion of the RMFC and an occult meniscal tear (commonly small radial or small peripheral partial-thickness longitudinal tears). RMFC contusions were reliably identified by radiologists in this study.Level of Evidence: II     

New strigolactone mimics: Structure–activity relationship and mode of action as germinating stimulants for parasitic weeds

Strigolactones (SLs) are new plant hormones with varies important bio-functions. This Letter deals with germination of seeds of parasitic weeds. Natural SLs have a too complex structure for synthesis. Therefore, there is an active search for SL analogues and mimics with a simpler structure with retention of activity. SL analogues all contain the D-ring connected with an enone moiety through an enol ether unit. A new mechanism for the hydrolysis SL analogues involving bidentate bound water and an α,β-hydrolase with a Ser-His-Asp catalytic triad has been proposed. Newly discovered SL mimics only have the D-ring with an appropriate leaving group at C-5. A mode of action for SL mimics was proposed for which now supporting evidence is provided. As predicted an extra methyl group at C-4 of the D-ring blocks the germination of seeds of parasitic weeds.     

Modeling the formation of root apices

The formation of new root apices from small groups of cells with different cellular patterns has been simulated using an existing model based on growth tensors. To generate an apex, a steady growth field was used. The pattern of cells evolved to approach the steady state. Two extreme types of progressions have been obtained : one leading to an apex with a single or a few apical cells, and the other to an apex with a quiescent centre. The change of structure while applying a steady growth tensor indicates that development may involve a succession of discrete growth tensors.     

Odor learning byLeptopilina boulardi,a specialist parasitoid (Hymenoptera: Eucoilidae)

We studied odor learning in Leptopilina boulardi,a specialist larval parasitoid of Drosophila melanogaster.The behavioral responses of differently experienced females to an artificial odor (Must de Cartier, Paris) were analyzed using a fourarmed airflow olfactometer. The responses of females with an oviposition experience in the presence of the perfume were compared with those of four control groups. As controls we used naive females, females with an oviposition experience in the absence of odor, females which had been previously exposed to perfume but without an oviposition experience, and females with an oviposition experience which also had been exposed to perfume but not at the same time. The results demonstrate that a specialist such as L. boulardican learn very well to respond to an artificial odor by associating this odor with a reward, i.e., an oviposition. The four control groups responded more or less in a similar way.     

Types of Systemic Reactions of Human Hemodynamics and Hemostasis to Multiple Occupational Migrations to the Polar Circle Regions

Effects of meridional migrations in shuttle from middle latitudes to regions beyond the Polar Circle, where an expedition and the organization of work shifts were being conducted, were studied. Three main types of systemic reactions of human hemodynamics and hemostasis were established. The first type was characterized by a moderate increase in the arterial blood pressure (BP) at the beginning of the shift with its subsequent normalization; by hypocoagulemia; and by an increase in the total phospholipid content, with a significant increase in the content of lysolecithins (an adaptive type). The second type was characterized by hypertension throughout the whole shift, by hypercoagulemia with significant changes in the phospholipid spectrum, and with a pronounced increase in the lysolecithin and cardiolipin fractions (a hypertensive type). The third type was characterized by a decrease in BP and an increase in heart rate (HR), by hypocoagulemia and an asthenic state associated with sleep disorders, and a decreased mental capacity (an asthenic type).     

DNA synthesis across an abasic lesion by yeast REV1 DNA polymerase

Abasic (apurinic/apyrimidinic) sites are among the most abundant DNA lesions in humans, and they present a strong block to replication. They are also highly mutagenic because when replicative DNA polymerases manage to insert a nucleotide opposite the lesion, they prefer to insert an A. Rev1, a member of Y-family DNA polymerases, does not obey the A-rule. This enzyme inserts a C opposite an abasic lesion with much greater catalytic efficiency than an A, G, or T. We present here the structure of yeast Rev1 in ternary complex with DNA containing an abasic lesion and with dCTP as the incoming nucleotide. The structure reveals a mechanism of synthesis across an abasic lesion that differs from that in other polymerases. The lesion is driven to an extrahelical position, and the incorporation of a C is mediated by an arginine (Arg324) that is conserved in all known orthologs of Rev1, including humans. The hydrophobic cavity that normally accommodates the unmodified G is instead filled with water molecules. Since Gs are especially prone to depurination through a spontaneous hydrolysis of the glycosidic bond, the ability of Rev1 to stabilize an abasic lesion in its active site and employ a surrogate arginine to incorporate a C provides a unique means for the “error-free” bypass of this noninstructional lesion.     

The importance of urgency in decision making based on dynamic information

A standard view in the literature is that decisions are the result of a process that accumulates evidence in favor of each alternative until such accumulation reaches a threshold and a decision is made. However, this view has been recently questioned by an alternative proposal that suggests that, instead of accumulated, evidence is combined with an urgency signal. Both theories have been mathematically formalized and supported by a variety of decision-making tasks with constant information. However, recently, tasks with changing information have shown to be more effective to study the dynamics of decision making. Recent research using one of such tasks, the tokens task, has shown that decisions are better described by an urgency mechanism than by an accumulation one. However, the results of that study could depend on a task where all fundamental information was noiseless and always present, favoring a mechanism of non-integration, such as the urgency one. Here, we wanted to address whether the same conclusions were also supported by an experimental paradigm in which sensory evidence was removed shortly after it was provided, making working memory necessary to properly perform the task. Here, we show that, under such condition, participants’ behavior could be explained by an urgency-gating mechanism that low-pass filters the mnemonic information and combines it with an urgency signal that grows with time but not by an accumulation process that integrates the same mnemonic information. Thus, our study supports the idea that, under certain situations with dynamic sensory information, decisions are better explained by an urgency-gating mechanism than by an accumulation one.     

Characteristics of Central Hemodynamics in Females with Different Body Mass Living in the European North

Hemodynamic indices were analyzed in 424 females aged 18–60 years with an insufficient, normal, or excessive body mass (BM). In females with an insufficient BM, the hemodynamic indices were indicative of a more intense myocardial function. In females with an excessive BM, a decrease in the contractile function of the myocardium was associated with an increase in peripheral vascular resistance, which might be responsible for elevated blood pressure.     

Exact solution of the Boltzmann kinetic equation for a Lorentzian gas

The classical methods of mathematical physics are applied to construct an integral solution to the Chapman-Cowling-Davydov equation, which is derived from the kinetic Boltzmann equation with a collision term in the Lorentzian-gas approximation. For a particular initial distribution, the solution is obtained in an explicit form in terms of a Whittaker function. It is shown that, on long (macroscopic) time scales, the evolving distribution function with an arbitrary initial shape approaches a Maxwellian distribution. This result agrees with the accepted views regarding the overall temporal evolution of an arbitrary unsteady isolated system.     

Development of a testicular tumour during cisclomiphene therapy

Enlargement of an atrophic testis occurred in an oligospermic patient during long-term therapy with a low dosage of cisclomiphene. Orchidectomy revealed an adult teratoma combined with an atypical seminoma. The development of a germinal-cell neoplasm during pituitary-gonadal stimulation therapy raises the question of a possible cause-effect relationship. Available evidence does not support this possibility. However, it is less clear whether hormonal influences may promote the growth of a germ-cell tumour focus. Therefore, prolonged treatment with such agents demands close supervision, particularly in patients with a predisposition to gonadal carcinogenesis.     

First asymmetric synthesis of (-)-lintetralin via intramolecular Friedel-Crafts-type cyclization

The asymmetric synthesis of an aryltetralin lignan, (-)-lintetralin, was achieved with an overall yield of 29% with seven steps. Key features of the synthesis are an asymmetric Strecker reaction, a diastereoselective Michael addition of the lithiated amino nitrile product to 5H-furan-2-one, and an intramolecular carbocationic cyclization to provide the desired ring skeleton with the correct configuration.     

Biomechanics of osteochondral impact with cushioning and graft Insertion: Cartilage damage is correlated with delivered energy

Articular cartilage is susceptible to impact injury. Impact may occur during events ranging from trauma to surgical insertion of an OsteoChondral Graft (OCG) into an OsteoChondral Recipient site (OCR). To evaluate energy density as a mediator of cartilage damage, a specialized drop tower apparatus was used to impact adult bovine samples while measuring contact force, cartilage surface displacement, and OCG advancement. When a single impact was applied to an isolated (non-inserted) OCG, force and surface displacement each rose monotonically and then declined. In each of five sequential impacts of increasing magnitude, applied to insert an OCG into an OCR, force rose rapidly to an initial peak, with minimal OCG advancement, and then to a second prolonged peak, with distinctive oscillations. Energy delivered to cartilage was confirmed to be higher with larger drop height and mass, and found to be lower with an interposed cushion or OCG insertion into an OCR. For both single and multiple impacts, the total energy density delivered to the articular cartilage correlated to damage, quantified as total crack length. The corresponding fracture toughness of the articular cartilage was 12.0 mJ/mm². Thus, the biomechanics of OCG insertion exhibits distinctive features compared to OCG impact without insertion, with energy delivery to the articular cartilage being a factor highly correlated with damage.     

Unpinning of a rotating wave in cardiac muscle by an electric field.

The possibility of terminating cardiac arrhythmias with electric fields of moderate intensity is a challenging problem from a fundamental point of view and an important issue for clinical applications. In an effort to understand how anatomical re-entries are affected by electric fields, we found that a weak shock, with an amplitude of an order of magnitude less than the defibrillating shock, may unpin the vortices rotating around the defects (obstacles). The unpinning results from a depolarization of the tissue near the obstacle, induced by an external electric field within a distance of order lambda approximately 1 mm. Unpinning was observed both in the FitzHugh model of excitable tissue, and in a specific Beeler-Reuter model of cardiac tissue. This theoretical observation suggests that anatomical re-entries can be transformed into functional re-entries, an effect that can be tested in experiments with cardiac muscle.     

THE FLAGELLAR APPARATUS OF CHRYSOCHROMULINA SP. (PRYMNESIOPHYCEAE)1

The flagellar apparatus of an undescribed species of Chrysochromulina Lackey that bears “eyelash” scales is reconstructed. The transitional region consists of two transitional plates each with an axosome, with no stellate pattern between them. Fine osmiophilic rings lie between the flagellar membrane and the outer doublets in the transitional region. The two jagella and the haptonema are inserted in a subapical depression that is lined ventrally by a spine-like projection formed by one of the parietal chloroplasts. The angles of insertion are similar to those of some other Chrysochromulina species in that both the haptonema and the right basal body lie at an extreme angle to the left basal body. The connectives of the apparatus consist of a striated distal band with a dorsal extension to the R1 and a ventral extension overlying the R2, a striated distal accessory band, an auxiliary connective from the right basal body to the adjacent ventral chloroplast, a well-developed intermediate band, two striated proximal bands, and a striated proximal accessory band. Of the microtubular roots in this Chrysochromulina species, three are associated with the left side of the cell (an R1 of 8+3; a small crystalline compound root, the R1C, associated with the R1; an R2 of three micro-tubules), and two are associated with the right basal body (an R3 of 2/2 microtubules with which the single-stranded R4 converges to form a 2/2+1 and then a 2/3 tiered arrangement). Comparisons are drawn with other species in the genus and related genera, particularly Prymne-sium.     

Genetic correlation in relation to differences in dosage of a stressor

We exposed the strains of Chlamydomonas isolated from an outbred laboratory population to a range of concentrations of salt (NaCl) up to an extirpative level that the base population could not tolerate. The genetic variance of yield increased with stress over the first half of this range before collapsing to nearly zero. The genetic correlation decreased with environmental distance, whether measured as a difference in dosage or as an environmental variance. This result is consistent with previous studies and provides a basis for interpreting adaptation to a deteriorating environment and the process of evolutionary rescue.     

A new formulation for the project scheduling problem under limited resources

In this paper we propose a new formulation for the Resource Constrained Project Scheduling Problem (RCPSP) and minimum makespan objective. The new formulation exploits three variables, one associated with the start time of an activity, one associated with the finish time of an activity, and the last one associated with the amount of an activity in progress at a given time. We provide an extensive experimentation, and a comparison with known mathematical formulations for the RCPSP in the literature.     

The effect of ferrous sulphate on the yield and manganese uptake of oats on sandy soil fertilized with natural pyrolusite

Summary The effects of soil treatments with ferrous sulphate and an equivalent amount of hydroquinone on the yield of dry matter and the manganese uptake of oats were investigated in pot experiments using a sandy soil deficient in manganese, with and without additions of finely ground, natural pyrolusite containing some manganite.In soil not fertilized with pyrolusite an application of hydroquinone gave a higher yield of dry matter and a considerably higher manganese uptake than an application of the equivalent quantity of ferrous sulphate.In soil fertilized with hydroquinone an increase of 23 per cent in the yield of dry matter and an increase of 50 per cent in the manganese uptake per pot were found when the soil was fertilized with 100 g of natural pyrolusite <50µ per pot. In soil fertilized with a quantity of ferrous sulphate equivalent to hydroquinone, an increase of 21 percent in the yield of dry matter and an increase of about 200 per cent in the manganese uptake per pot were found when the 100 g of pyrolusite was applied.     

Serine acetyltransferase from Escherichia coli is a dimer of trimers

Equilibrium sedimentation studies show that the serine acetyltransferase (SAT) of Escherichia coli is a hexamer. The results of velocity sedimentation and quasi-elastic light scattering experiments suggest that the identical subunits are loosely packed and/or arranged in an ellipsoidal fashion. Chemical cross-linking studies indicate that the fundamental unit of quaternary structure is a trimer. The likelihood, therefore, is that in solution SAT exists as an open arrangement of paired trimers. Crystals of SAT have 32 symmetry, consistent with such an arrangement, and the cell density function is that expected for a hexamer. Electron microscopy with negative staining provides further evidence that SAT has an ellipsoidal subunit organization, the dimensions of the particles consistent with the proposed paired trimeric subunit arrangement. A bead model analysis supports the view that SAT has a low packing density and, furthermore, indicates that the monomers may have an ellipsoidal shape. Such a view is in keeping with the ellipsoidal subunit shape of trimeric LpxA, an acyltransferase with which SAT shares contiguous repeats of a hexapeptide motif.     

Empty sites can promote altruistic behavior

Spatial structure has been shown to promote altruistic behavior, however, it also increases the intensity of competition among relatives. Our purpose here is to develop a model in which this competition is minimized, more precisely a local increase in fecundity has a minimal competitive effect on the fitness of nearby individuals. We work with an island model in which sites are allowed to be empty, choosing our demographic rules so that in patches with higher fecundity, empty sites are filled at a higher rate. We also allow dispersal rates to evolve in response to the proportion of empty sites in the patch. Patches with different numbers of empty sites differ in frequency, in within-patch consanguinity, and in reproductive value. Using an inclusive fitness argument, we show that our model does promote altruism; indeed Hamilton's Rule is shown to hold. The only negative effect on an actor of a gift of fecundity to a patchmate turns out to be a slight decrease in reproductive value due to an increased probability of an empty site being occupied. We show that altruists are most favored in islands with an intermediate number of empty sites.     

Galactosylceramide containing omega-amino-fatty acids: preparation, characterization, and sulfotransferase acceptor.

For preparation of an affinity ligand, an N-fatty acyl moiety of galactosylceramide (GalCer) was chemically replaced with omega-amino-fatty acid including amino-n-hexanoic acid or amino-n-dodecanoic acid to obtain omega-aminoGalCer. For the synthesis of the compound, galactosylsphingosine (GalSph) was coupled with N-trifluoroacetyl omega-amino-fatty acid which was prepared by a reaction with S-ethyltrifluorothioacetate. After removal of the N-trifluoroacetyl group in a mild alkaline solution, in which an N-fatty acyl group was retained, aminoGalCer composed of an N-hexanoyl or an N-dodecanoyl group was obtained with an overall yield of 90%. Their chemical structures were confirmed by proton nuclear magnetic resonance and fast atom bombardment-mass spectrometries. These aminoGalCers and GalSph as well as immobilized aminoGalCer were sulfated by a glycolipid sulfotransferase from rat kidney. Furthermore, immobilized aminoGalCer on gel matrix was used for affinity chromatography of the sulfotransferase, resulting in an excellent increase in the purification (14,000-fold) with a recovery rate of 40%.