Extrinsic Magnetotransport Phenomena in Ferromagnetic Oxides

This review is focused on extrinsic magnetotransport effects in ferromagnetic oxides. It consists of two parts; the second part is devoted to an overview of experimental data and theoretical models for extrinsic magnetotransport phenomena. Here a critical discussion of domain-wall scattering is given. Results on surfacial and interfacial magnetism in oxides are presented. Spin-polarized tunnelling in ferromagnetic junctions is reviewed and grain-boundary magnetoresistance is interpreted within a model of spin-polarized tunnelling through natural oxide barriers. The situation in ferromagnetic oxides is compared with data and models for conventional ferromagnets. The first part of the review summarizes basic material properties, especially data on the spin-polarization and evidence for half-metallicity. Furthermore, intrinsic conduction mechanisms are discussed. An outlook on the further development of oxide spin-electronics concludes this review.Comment: 133 pages, 47 figures, submitted to Rep. Prog. Phy

Neurodevelopmental disorders in children aged 2-9 years: Population-based burden estimates across five regions in India.

BACKGROUND: Neurodevelopmental disorders (NDDs) compromise the development and attainment of full social and economic potential at individual, family, community, and country levels. Paucity of data on NDDs slows down policy and programmatic action in most developing countries despite perceived high burden. METHODS AND FINDINGS: We assessed 3,964 children (with almost equal number of boys and girls distributed in 2-<6 and 6-9 year age categories) identified from five geographically diverse populations in India using cluster sampling technique (probability proportionate to population size). These were from the North-Central, i.e., Palwal (N = 998; all rural, 16.4% non-Hindu, 25.3% from scheduled caste/tribe [SC-ST] [these are considered underserved communities who are eligible for affirmative action]); North, i.e., Kangra (N = 997; 91.6% rural, 3.7% non-Hindu, 25.3% SC-ST); East, i.e., Dhenkanal (N = 981; 89.8% rural, 1.2% non-Hindu, 38.0% SC-ST); South, i.e., Hyderabad (N = 495; all urban, 25.7% non-Hindu, 27.3% SC-ST) and West, i.e., North Goa (N = 493; 68.0% rural, 11.4% non-Hindu, 18.5% SC-ST). All children were assessed for vision impairment (VI), epilepsy (Epi), neuromotor impairments including cerebral palsy (NMI-CP), hearing impairment (HI), speech and language disorders, autism spectrum disorders (ASDs), and intellectual disability (ID). Furthermore, 6-9-year-old children were also assessed for attention deficit hyperactivity disorder (ADHD) and learning disorders (LDs). We standardized sample characteristics as per Census of India 2011 to arrive at district level and all-sites-pooled estimates. Site-specific prevalence of any of seven NDDs in 2-<6 year olds ranged from 2.9% (95% CI 1.6-5.5) to 18.7% (95% CI 14.7-23.6), and for any of nine NDDs in the 6-9-year-old children, from 6.5% (95% CI 4.6-9.1) to 18.5% (95% CI 15.3-22.3). Two or more NDDs were present in 0.4% (95% CI 0.1-1.7) to 4.3% (95% CI 2.2-8.2) in the younger age category and 0.7% (95% CI 0.2-2.0) to 5.3% (95% CI 3.3-8.2) in the older age category. All-site-pooled estimates for NDDs were 9.2% (95% CI 7.5-11.2) and 13.6% (95% CI 11.3-16.2) in children of 2-<6 and 6-9 year age categories, respectively, without significant difference according to gender, rural/urban residence, or religion; almost one-fifth of these children had more than one NDD. The pooled estimates for prevalence increased by up to three percentage points when these were adjusted for national rates of stunting or low birth weight (LBW). HI, ID, speech and language disorders, Epi, and LDs were the common NDDs across sites. Upon risk modelling, noninstitutional delivery, history of perinatal asphyxia, neonatal illness, postnatal neurological/brain infections, stunting, LBW/prematurity, and older age category (6-9 year) were significantly associated with NDDs. The study sample was underrepresentative of stunting and LBW and had a 15.6% refusal. These factors could be contributing to underestimation of the true NDD burden in our population. CONCLUSIONS: The study identifies NDDs in children aged 2-9 years as a significant public health burden for India. HI was higher than and ASD prevalence comparable to the published global literature. Most risk factors of NDDs were modifiable and amenable to public health interventions

Homolytic displacement at carbon. Part 3. First example of α-attack on the allenyl- and prop-2-ynyl-cobaloximes

Allenylcobaloxime reacts with substituted benzenesulphonyl chlorides in an inert atmosphere under irradiation with tungsten lamps to give good yields of allenyl sulphones. However, the same reactions carried out in Srinivasan's photoreactor using a 400 W medium-pressure mercury lamp or under thermal conditions give exclusively prop-2-ynyl sulphones, by regiospecific rearrangement, in good yields. The corresponding reactions of (3,3-disubstituted allenyl) cobaloximes afford 1,1-disubstituted prop-2-ynyl sulphones irrespective of the conditions used. Similarly, prop-2-ynyl sulphones are formed exclusively in the reactions of prop-2-ynylcobaloxime with organosulphonyl chlorides under thermal and photochemical conditions. The reactions are believed to take place through a chain mechanism in which cobaloxime(II), present adventitously or formed by partial homolysis of the substrate cobaloxime, abstracts a chlorine atom from the organosulphonyl chloride to give the organosulphonyl radical RS<SUP>&#183;</SUP>O<SUB>2</SUB>. Depending upon the reaction conditions and the nature of cobaloxime, RS<SUP>&#183;</SUP>O<SUB>2</SUB> attacks the &#945;- or the &#947;-carbon atom of the axial organic group of the cobaloxime, thereby displacing cobaloxime(II) and giving the observed organic product

Survey on SAP and its application in public-key cryptography

The concept of the semigroup action problem (SAP) was first introduced by Monico in 2002. Monico explained in his paper that the discrete logarithm problem (DLP) can be generalized to SAP. After defining the action problem in a semigroup, the concept was extended using different mathematical structures. In this paper, we discuss the concept of SAP and present a detailed survey of the work which has been done using it in public-key cryptography

Cervical tuberculous lymphadenopathy: changing clinical pattern and concepts in management

Tuberculosis is one of the biggest health challenges the world is facing. In this study the clinical pattern of patients with cervical lymphadenitis, who presented to the ear, nose, and throat outpatient department of the Government Medical College Hospital, Chandigarh, India between June 1997 and May 1998 is recorded. Tuberculosis accounted for 60 out of 94 cases of cervical lymph node enlargement. The commonest age group affected was 11-20 years. Constitutional symptoms were not present in most of the patients. Multiple matted nodes were seen in 23 patients but a single discrete node was seen in 18 patients. Upper deep jugular nodes were the most commonly affected lymph nodes. Discharging sinus and abscess formation were uncommon. Fine needle aspiration cytology yielded a positive diagnosis in 52 out of 56 patients. Chest lesions on radiography were evident in 16% of the patients. Mantoux test was positive and was more than 15 mm in most of the patients. This study shows that the classical picture of "scrofula" is no longer seen nowadays and can probably be explained by the earlier presentation of the disease.
All the patients were treated with short course daily chemotherapy for six months. Surgery was not required in the majority of patients except in four cases where excision biopsy was performed. Patients with abscess formation were managed with wide bore needle aspiration only. With a minimum six month period of follow up, no patient was found to have a recurrence of local or systemic disease.
This study emphasises the role of fine needle aspiration cytology in diagnosis and confirms the efficacy of six months short course chemotherapy.


Keywords: cervical lymphadenitis; tuberculosis; antitubercular chemotherap

S<SUB>H</SUB>2' reaction in organocobaloximes: synthesis and 1,3-rearrangement of exo-methylene alicyclic allyl sulfones

Photostimulated reactions of cyclopentenylmethyl-, cyclohexenylmethyl- and &#945;-pinenyl cobaloximes with arenesulfonyl halides result in the formation of corresponding exo-methylene cycloalkylsulfones in 82-98% isolated yields. The product formation is rationalized by a radical chain mechanism involving an SH2' displacement of cobaloxime(II) from organocobaloximes by sulfonyl radical. Reaction under thermal condition, however, provides a mixture of exo-methylene cycloalkylsulfone and its endoisomer. Independent experiments confirmed that the endo-isomer arises from a facile 1,3-allylic rearrangement of the exo-isomer. From mechanistic and theoretical studies the rearrangement is proposed to involve a [1,3]-sigmatropic migration of sulfonyl group

Homolytic displacement at saturated carbon in organocobaloximes. Part 4

Benzyl and para-substituted benzylcobaloximes react with substituted arenesulphonyl chlorides under photochemical and anaerobic conditions at 0°C to give a variety of products including the sulphones, bibenzyls, and benzyl ethers of dimethylglyoxime in variable yields. However, when the reactions are carried out in the presence of a 1 mol excess of pyridine, the yield of sulphones is increased by at least 20% in each case. The corresponding yield of bibenzyls is decreased and no trace of the benzyl ether of dimethylglyoxime is formed. On the other hand, the reaction of heteroaromatic methyl cobaloximes with arenesulphonyl chlorides form the corresponding sulphones as the exclusive organic product in good yield and with no side products. The reactions are interpreted in terms of a direct attack of the arenesulphonyl radical on the α carbon of the benzyl and heteroaromatic methyl ligand

Clinico-anesthetic changes following administration of propofol alone and in combination of meperidine and pentazocine lactate in dogs

Aim: The aim of this study is to find out the effect of propofol and its combination with meperidine and pentazocine lactate on certain clinico-anesthetic profiles in dogs. Materials and Methods: 15 apparently healthy mongrel dogs of either sex of about 1 year of age were randomly divided into three groups of five dogs each. The animals of Group I were administered propofol intravenously alone “to effect,” whereas meperidine at 2 mg/kgb.wt. and pentazocine lactate at 2 mg/kg b.wt. were injected intramuscularly 15 min before propofol “to effect” in Groups II and III, respectively. Atropine sulfate at 0.04 mg/kgb.wt. was injected intramuscularly 20 min before each treatment. Rectal temperature, heart rate, respiration rate, and anesthetic indices were recorded before and at 5, 10, 20, 30, and 60 min of induction. Results: As compared to Group I, the animals of Groups II and III exhibited a significant decrease (p<0.05) in the level of rectal temperature, respiration rate, and heart rate. Duration of recumbency, time of standing, time of recovery as well as the duration of analgesia were longer in pentazocine lactate (Group III) followed by meperidine (Group II) as compared to propofol alone (Group I). Meperidine treated dogs showed defecation and muscle twitching during anesthesia. Conclusion: Meperidine and pentazocine are suitable opioids used in combination with propofol for achieving surgical anesthesia and helpful in reduction of propofol dose