Comparative experimental and Density Functional Theory (DFT) study of the physical properties of MgB2 and AlB2

In present study, we report an inter-comparison of various physical and electronic properties of MgB2 and AlB2. Interestingly, the sign of S(T) is +ve for MgB2 the same is -ve for AlB2. This is consistent our band structure plots. We fitted the experimental specific heat of MgB2 to Debye Einstein model and estimated the value of Debye temperature (theta) and Sommerfeld constant (gamma) for electronic specific heat. Further, from gamma the electronic density of states (DOS) at Fermi level N(EF) is calculated. From the ratio of experimental N (EF) and the one being calculated from DFT, we obtained value of Lembda to be 1.84, thus placing MgB2 in the strong coupling BCS category. The electronic specific heat of MgB2 is also fitted below Tc using pi-model and found that it is a two gap superconductor. The calculated values of two gaps are in good agreement with earlier reports. Our results clearly demonstrate that the superconductivity of MgB2 is due to very large phonon contribution from its stretched lattice. The same two effects are obviously missing in AlB2 and hence it is not superconducting. DFT calculations demonstrated that for MgB2 the majority of states come from Sigma and Pi 2p states of boron on the other hand Sigma band at Fermi level for AlB2 is absent. This leads to a weak electron phonon coupling and also to hole deficiency as Pi bands are known to be of electron type and hence obviously the AlB2 is not superconducting. The DFT calculations are consistent with the measured physical properties of the studied borides, i.e., MgB2 and AlB2Comment: 16 pages Text + Figs: comments/suggestions welcome ([email protected])/www.freewebs.com/vpsawana

Genetička raznolikost unutar 18S rRNA i aktin-lokusa Cryptosporidium scrofarum (Apicomplexa: Cryptosporidiidae) pri invaziji domaćih svinja (Sus scrofa domesticus) u Indiji

The genetic diversity was studied of Cryptosporidium scrofarum (syn Cryptosporidium pig genotype II) of domestic pigs (Sus scrofa domesticus) from Punjab, India. Nested PCR amplification targeting the 18S rRNA and actin gene loci from Cryptosporidium positive samples was carried out, and the amplicons were sequenced. Phylogenetic comparison of a partial 18S rRNA gene revealed that they were genetically most similar to C. scrofarum isolated from other parts of the world. However, comparison of sequences representing a fragment of the genomic actin locus identified a new genotype conserved within the isolates sampled from India but distinct from other published sequences, suggesting the presence of a different Indian genotype.U ovom je radu istraživana genetička raznolikost Cryptosporidium scrofarum (syn Cryptosporidium pig genotype II) domaćih svinja (Sus scrofa domesticus) iz regije Punjab, Indija. Provedeno je umnožavanje 18S rRNA i lokusa aktin-gena pomoću ugniježđene PCR metode iz uzoraka pozitivnih na Cryptosporidium te su sekvencirani amplikoni. Filogenetska usporedba parcijalnog 18S rRNA gena pokazala je da su uzorci genetski najsličniji C. scrofarum izoliranom u drugim dijelovima svijeta. Također, usporedba sekvencija dijela lokusa genomskog aktina otkrila je novi genotip očuvan unutar izolata uzorkovanih u Indiji, ali različitih od drugih objavljenih sekvencija, upućujući na postojanje zasebnog indijskog genotipa

Effect of sintering temperature on the nature of weak links and flux pinning mechanism in La1.85Sr0.15CuO4 superconductor

AC and DC susceptibility study is carried out to investigate the granular nature of La1.85Sr0.15CuO4 superconductor. Presence of weak links and flux pinning phenomena are two important implications of granular type II high temperature superconductors. Weak links manifested as Superconductor-Insulator-Superconductor (SIS) / Superconductor-Normal metal-superconductor (SNS) Josephson Junctions are investigated from the temperature and field dependence study of AC susceptibility. On the other hand, DC susceptibility measurement is used to study the flux pinning mechanism. Mechanism of flux pinning is dependent on the nature and size of the pinning centres as well as on the microstructure wavelength. Thus, the nature of grain boundaries plays an important role in determining the nature of pinning mechanism of flux lines. In the present work, effect of sintering temperature on the nature of weak links and flux pinning mechanism in the bulk polycrystalline sample of La1.85Sr0.15CuO4 superconductor is studied

SUSCEPTIBILITY OF RHIPICEPHALUS SANGUINEUS SENSULATO (S.L.) LATREILLE (ACARI: IXODIDAE) TO CYPERMETHRIN, IVERMECTIN, AND AMITRAZ

Chemical acaricides, viz. amitraz, cypermethrin, and ivermectin have been in use for control of ectoparasites (particularly ticks) in domestic animals over the past two decades. The present study aimed to appraise the acaricidal effects of ivermectin (IVM), amitraz, and cypermethrin against brown dog tick Rhipicephalus sanguineus sensulato (s.l.), by in-vitro bioassay based susceptibility tests, viz. larval immersion test and larval packet test. Lethal concentrations (LC50 and LC95) values of acaricides were ascertained by applying regression equation analysis to the probit transformed data of mortality and resistance factors (RF) were determined. LC50 values of 11.39, 22.51, and 10.75 ppm, and LC95 values of 57.06, 78.74, and 50.28 ppm were estimated for amitraz, cypermethrin, and ivermectin, respectively. The susceptible status against amitraz and ivermectin whereas, the resistance of level I against cypermethrin was recorded in the study. The present study is the only report of resistance to cypermethrin in R. sanguineus (s.l.), ticks from this region

Recall System in Dental Practice: A Review

The patients are generally encouraged to attend their recall visits at regular intervals of six months, irrespective of the individual's risk of developing dental disease. The major important role of the dental recall has been seen as the prevention and early detection of dental caries and periodontal disease in particular. The recommendation of a six-month recall interval has become a mandatory practice in dental clinics. Thus, this paper reviews about the guidelines relating to the recall of the patients, various types of recall systems and how we can establish a recall visit. In addition, the paper focuses about the ideal recall visit as well

TOXOCARIASIS IN PUPPY - MORPHOLOGICAL DESCRIPTION AND CLINICAL MANAGEMENT

A 34-day-old, male Bully pup was presented in veterinary clinics with an uncertain anamnestic history of anorexia, lethargy, abdominal pain, and discomfort. On clinical examination, the pup had pale conjunctiva with a pot-bellied appearance and expelled cream-colored roundworms in feces. Blood and fecal samples were collected and analyzed. Hemoglobin and PCV values were lower, depicting anemia. A qualitative and quantitative examination of the fecal sample was carried out and results showed infection with Toxocara canis with fecal egg count (FEC) of 3200/gram of feces. Gross and light microscopic examination revealed the presence of adults of Toxocara canis with distinctive morphological features. Apropos, the pup was treated with a combination of pyrantel pamoate and fenbendazole orally @10mg/kg body weight, repeated after 14 days. The pup recovered successfully, as evidenced by decreased FECs, increased weight gain, and a high hematocrit score

Temperature and field dependence of thermally activated flux flow resistance in Bi2Sr2CaCu2O8+{\delta} superconductor

We study the temperature dependence of the resistivity as a function of magnetic field in superconducting transition (Tconset - TcR=0) region for different Bi2Sr2CaCu2O8+{\delta} superconducting samples being synthesized using sol-gel method. The superconducting transition temperature (TcR=0) of the studied samples is increased from 32 K to 82K by simply increasing the final sintering temperature with an improved grains morphology. On the other hand, broadening of transition is increased substantially with decrease in sintering temperature; this is because Tconset is not affected much with grains morphology. Further broadening of the superconducting transition is seen under magnetic field, which is being explained on the basis of thermally activated flux flow (TAFF) below superconducting transition temperature (Tc). TAFF activation energy (U0) is calculated using the resistive broadening of samples in the presence of magnetic field. Temperature dependence of TAFF activation energy revealed linear temperature dependence for all the samples. Further, magnetic field dependence is found to obey power law for all the samples and the negative exponent is increased with increase in sintering temperature or the improved grains morphology for different Bi-2212 samples. We believe that the sintering temperature and the ensuing role of grain morphology is yet a key issue to be addressed in case of cuprate superconductors.Comment: 17 pages text + Figs: comments/suggestions ([email protected]

Identification and manipulation of defects in black phosphorus

We identify and manipulate commonly occurring defects in black phosphorus, combining scanning tunneling microscopy experiments with density functional theory calculations. A ubiquitous defect, imaged at negative bias as a bright dumbbell extending over several nanometers, is shown to arise from a substitutional Sn impurity in the second sublayer. Another frequently observed defect type is identified as arising from an interstitial Sn atom; this defect can be switched to a more stable configuration consisting of a Sn substitutional defect + P adatom, by application of an electrical pulse via the STM tip. DFT calculations show that this pulse-induced structural transition switches the system from a non-magnetic configuration to a magnetic one. We introduce States Projected Onto Individual Layers (SPOIL) quantities which provide information about atom-wise and orbital-wise contributions to bias-dependent features observed in STM images.We acknowledge the Indo-French Centre for the Promotion of Advanced Scientific Research (CEFIPRA) for funding our collaboration. We are especially grateful for assistance provided by the Late Ms. A. Sathidevi. We are grateful to the ANR and MOST (DEFINE2D Project No. ANR-20-CE09-0023, MOST 110-2923-M-002-010) for financial support and the TUE-CMS, JNCASR, and the Sheikh Saqr Laboratory, JNCASR, for computational resources. D.S. acknowledges support from the NPDF of the Science and Engineering Research Board (SERB), Government of India.Peer reviewe