257 research outputs found
A bacteriological study of the natural flora of edible oyster, Crassostrea madrasensis
The total viable bacterial populations in the oysters and the sea water from the edible oyster farm at Tuticorin were in the range of 10 super(3) to 10 super(4) per ml and 1 super(2) to 10 super(3) per ml respectively. The maximum most probable number of faecal coliform recorded during the one year period of study of both the oysters and seawater were 33 per 100 ml. Pathogenic bacteria (Salmonella sp., Vibrio cholerae, coagulase positive staphylococci and faecal streptococci were absent in oysters and farm water. Study of 197 (98 taken from oyster liquid and 99 from oyster farm water) randomly isolated cultures indicated that gram negative asporogenus rod-like bacteria of the Vibrio, Flavobacterium, Achromobacter and Pseudomonas groups were the dominant flora of the oyster liquid as well as seawater
Non-Fermi-liquid behavior in nearly ferromagnetic metallic SrIrO3 single crystals
We report transport and thermodynamic properties of single-crystal SrIrO3 as
a function of temperature T and applied magnetic field H. We find that SrIrO3
is a non-Fermi-liquid metal near a ferromagnetic instability, as characterized
by the following properties: (1) small ordered moment but no evidence for
long-range order down to 1.7 K; (2) strongly enhanced magnetic susceptibility
that diverges as T or T1/2 at low temperatures, depending on the applied field;
(3) heat capacity C(T,H) ~ -Tlog T that is readily amplified by low applied
fields; (4) a strikingly large Wilson ratio at T< 4K; and (5) a T3/2-dependence
of electrical resistivity over the range 1.7 < T < 120 K. A phase diagram based
on the data implies SrIrO3 is a rare example of a stoichiometric oxide compound
that exhibits non-Fermi-liquid behavior near a quantum critical point (T = 0
and H = 0.23 T)
High-temperature weak ferromagnetism on the verge of a metallic state: Impact of dilute Sr-doping on BaIrO3
The 5d-electron based BaIrO3 is a nonmetallic weak ferromagnet with a Curie
temperature at Tc=175 K. Its largely extended orbitals generate strong
electron-lattice coupling, and magnetism and electronic structure are thus
critically linked to the lattice degree of freedom. Here we report results of
our transport and magnetic study on slightly Sr doped BaIrO3. It is found that
dilute Sr-doping drastically suppresses Tc, and instantaneously leads to a
nonmetal-metal transition at high temperatures. All results highlight the
instability of the ground state and the subtle relation between magnetic
ordering and electron mobility. It is clear that BaIrO3 along with very few
other systems represents a class of materials where the magnetic and transport
properties can effectively be tuned by slight alterations in lattice
parameters
Mathematical approach towards non-stepwise performance assessment in HUASB reactor for wastewater treatment from pulp and paper mills
A lab-scale Hybrid Upflow Anaerobic Sludge Blanket (HUASB) reactor with a working volume of 6.5 litres has been taken for the performance analysis, in the treatability study of pulp and paper mill wastewater. In order to analyze the performance of the reactor, operational parameter like hydraulic retention time (HRT) was varied from 10, 20, 30 and 40 h. In addition to that, performance parameters like chemical oxygen demand (COD), pH, volatile fatty acids (VFA), alkalinity, gas production and VFA/alkalinity ratio are analyzed to check the reactor efficacy. The maximum COD removal efficiency of 81.3% is obtained at 40 h HRT, with gas production (methane content of 58%). Also, the obtained results are fitted to the kinetic models like the standard first order, first order and second order to evaluate the performance of the HUASB reactor
Colossal Magnetoresistance by Avoiding a Ferromagnetic State in the Mott System Ca3Ru2O7
Transport and magnetic studies of Ca3Ru2O7 for temperatures ranging from 0.4
K to 56 K and magnetic fields, B, up to 45 T leads to strikingly different
behavior when the field is applied along the different crystal axes. A
ferromagnetic (FM) state with full spin polarization is achieved for B||a-axis,
but colossal magnetoresistance is realized only for B||b-axis. For B||c-axis,
Shubnikov-de Haas oscillations are observed and followed by a less resistive
state than for B||a. Hence, in contrast to standard colossal magnetoresistive
materials, the FM phase is the least favorable for electron hopping. These
properties together with highly unusual spin-charge-lattice coupling near the
Mott transition (48 K) are driven by the orbital degrees of freedom.Comment: 15 pages including 3 figure
Partial antiferromagnetism in spin-chain Sr5Rh4O12, Ca5Ir3O12 and Ca4IrO6 single crystals
We report a structural, thermodynamic and transport study of the newly
synthesized Sr5Rh4O12, Ca5Ir3O12 and Ca4IrO6 single crystals. These
quasi-one-dimensional insulators consist of a triangular lattice of spin chains
running along the c-axis, and are commonly characterized by a partial
antiferromagnetic (AFM) order, a small entropy removal associated with the
phase transitions and a sizable low-temperature specific heat linearly
proportional to temperature. Sr5Rh4O12 is defined by an AFM order below 23 K
with strong evidence for an Ising character and two step-like transitions in
isothermal magnetization leading to a ferrimagnetic state at 2.4 T and a
ferromagnetic state at 4.8 T, respectively. Ca5Ir3O12 and Ca4IrO6 are also
antiferromagnetically ordered below 7.8 K and 12 K, respectively, and show an
unusually large ratio of the Curie-Weiss temperature to the Neel temperature.
In particular, Ca5Ir3O12, which includes both Ir4+ and Ir5+ ions, reveals that
only S=1/2 spins of the Ir4+ ions are involved in the magnetic ordering whereas
S=3/2 spins of the Ir5+ ions remain disordered. All results suggest the
presence of the geometrical frustration that causes incomplete long-range AFM
order in these quasi-one-dimensional compounds
Borderline magnetism in Sr4Ru3O10: Impact of dilute La and Ca doping on itinerant ferromagnetism and metamagnetism
An investigation of La and Ca doped Sr4Ru3O10, featuring a coexistence of
interlayer ferromagnetism and intralayer metamagnetism, is presented. La doping
readily changes magnetism between ferromagnetism and metamagnetism by tuning
the density of states. It also results in different Curie temperatures for the
c-axis and the basal plane, highlighting a rare spin-orbit coupling with the
crystal field states. In contrast, Ca doping enhances the c-axis ferromagnetism
and the magnetic anisotropy. La doping also induces a dimensional crossover in
the interlayer transport whereas Ca doping exhibits a tunneling
magnetoresistance and an extraordinary T3/2-dependence of the resisitivity. The
drastic changes caused by the dilute doping demonstrate a rare borderline
magnetism that is delicately linked to the interplay of the density of states
and spin-orbit coupling.Comment: 5 figure
Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
We investigated electronic structure of 5d transition-metal oxide Sr2IrO4
using angle-resolved photoemission, optical conductivity, and x-ray absorption
measurements and first-principles band calculations. The system was found to be
well described by novel effective total angular momentum Jeff states, in which
relativistic spin-orbit (SO) coupling is fully taken into account under a large
crystal field. Despite of delocalized Ir 5d states, the Jeff-states form so
narrow bands that even a small correlation energy leads to the Jeff = 1/2 Mott
ground state with unique electronic and magnetic behaviors, suggesting a new
class of the Jeff quantum spin driven correlated-electron phenomena.Comment: 12 pages, 4 figure
Advanced Triple Negative Breast Cancer in Pregnancy
Breast cancer is one of the most common prevalent malignancies in pregnancy. The management is challenging as it involves both maternal and fetal well-being. A 41-year-old lady was diagnosed with triple negative breast cancer in the second trimester pregnancy. Neoadjuvant chemotherapy was decided as she opted for a continuation of pregnancy and refusal for mastectomy. After completing the second cycle of chemotherapy, she developed preterm premature rupture of membrane and had fetal malposition requiring an emergency caesarean section. Computed tomography staging revealed an advanced disease, hence needing palliative treatment and support. The difficulties in managing this case arise in choosing the best treatment to preserve both maternal and fetal wellbeing
- …