Graphene overcoats for ultra-high storage density magnetic media.

Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond ~1 Tb/in2. This requires the thickness of carbon overcoats (COCs) to be <2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in2 areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media.

Role of Antibiotic Cement Coated Nailing in Infected Nonunion of Tibia.

INTRODUCTION: Infected nonunion of long bones is a chronic and debilitating disorder. It is more difficult to deal with when the implant used for internal fixation itself becomes a potential media for infection because of bacterial adhesion and biofilm formation. Traditionally, it is managed by two-stage procedure for controlling the infection first and then treating the nonunion. This study has been undertaken to explore antibiotic cement coated nailing as single stage treatment modality for treating infection and achieving stability at the same time. MATERIALS AND METHODS: Twenty patients (above 18 years of age) with infected nonunion of tibia with bone gap less than 2 cm were managed using antibiotic cement coated K-nail. Antibiotic cement nail was prepared using endotracheal tube method. Antibiotics used were a combination of vancomycin and teicoplanin. RESULTS: Infection was controlled in 95% of the patients. Bony union was achieved in 12 of 20 (60%) patients with antibiotic cement nailing as the only procedure with average time of union of 32 weeks. Remaining 8 patients required additional procedures like bone grafting or exchange nailing and these were done in six patients, with union of fracture. Two patients refused to undergo further procedures. Complications encountered were difficult nail removal in three cases, broken nail in two cases, and bent nail in one case. Recurrence of infection was observed in two patients. Average period of follow-up was 13 months. CONCLUSION: Antibiotic cement impregnated nailing is a simple, economical and effective single stage procedure for the management of infected nonunion of tibia. It is advantageous over external fixators, as it eliminates the complications of external fixators and has good patient compliance. The method utilizes existing easily available instrumentation and materials and is technically less demanding, and therefore can be performed at any general orthopaedic center.

Low level nitrogen laser therapy in pulmonary tuberculosis.

BACKGROUND AND AIMS: WHO estimated 9 million new Tuberculosis cases and 1.5 million TB deaths in 2013. Globally 480000 Multi drug resistant tuberculosis cases were noted and majority of them were in India, China and Russian federation. Multi drug resistant tuberculosis cases are difficult to treat and have high mortality. Presently, it was aimed to assess prevalence of drug resistance in M. tuberculosis isolates in Central India, to check the in-vitro effect of N2 Laser on M. tuberculosis and to study the therapeutic effect of intra cavitary N2 laser on pulmonary Tuberculosis cases not responding to chemotherapy. MATERIALS AND METHODS: Drug sensitivity testing was carried out on 567 isolates of M. tuberculosis by proportion method. To check the effect of N2 laser on M. tuberculosis, suspension spread on LJ plate and part of the plate exposed to N2 laser for 10 min and plate incubated for 4 weeks to see the effect. For exposure to lung cavity a needle was introduced into the lung through which fiber was passed to the cavity for N2 laser irradiation for 10 min. RESULTS: Only 12.8% isolates of M. tuberculosis were sensitive to all anti-Tubercular drugs and 21.5% were found to be resistant to Rifampicin qualifying definition of Multi drug resistant tuberculosis. Bactericidal effect for N2 laser was seen in-vitro on exposure to N2 laser. Clinical improvement occurred in 90% of the 96 patients; 60% of the patients showed improvement on their X-rays and 75% turned out to be Acid fast bacilli smear negative in 4 to 15 days. CONCLUSIONS: Intra-cavitory N2 laser therapy was found to have remarkable success as an adjunct to chemotherapy.

Outcome of lumbar spinal fusion surgery in obese patients: a systematic review and meta-analysis.

The aim of this study was to determine whether obesity affects pain, surgical and functional outcomes following lumbar spinal fusion for low back pain (LBP). A systematic literature review and meta-analysis was made of those studies that compared the outcome of lumbar spinal fusion for LBP in obese and non-obese patients. A total of 17 studies were included in the meta-analysis. There was no difference in the pain and functional outcomes. Lumbar spinal fusion in the obese patient resulted in a statistically significantly greater intra-operative blood loss (weighted mean difference: 54.04 ml; 95% confidence interval (CI) 15.08 to 93.00; n = 112; p = 0.007) more complications (odds ratio: 1.91; 95% CI 1.68 to 2.18; n = 43858; p < 0.001) and longer duration of surgery (25.75 mins; 95% CI 15.61 to 35.90; n = 258; p < 0.001). Obese patients have greater intra-operative blood loss, more complications and longer duration of surgery but pain and functional outcome are similar to non-obese patients. Based on these results, obesity is not a contraindication to lumbar spinal fusion.

Understanding the role of nitrogen in plasma-assisted surface modification of magnetic recording media with and without ultrathin carbon overcoats.

A novel scheme of pre-surface modification of media using mixed argon-nitrogen plasma is proposed to improve the protection performance of 1.5 nm carbon overcoats (COC) on media produced by a facile pulsed DC sputtering technique. We observe stable and lower friction, higher wear resistance, higher oxidation resistance, and lower surface polarity for the media sample modified in 70%Ar + 30%N2 plasma and possessing 1.5 nm COC as compared to samples prepared using gaseous compositions of 100%Ar and 50%Ar + 50%N2 with 1.5 nm COC. Raman and X-ray photoelectron spectroscopy results suggest that the surface modification process does not affect the microstructure of the grown COC. Instead, the improved tribological, corrosion-resistant and oxidation-resistant characteristics after 70%Ar + 30%N2 plasma-assisted modification can be attributed to, firstly, the enrichment in surface and interfacial bonding, leading to interfacial strength, and secondly, more effective removal of ambient oxygen from the media surface, leading to stronger adhesion of the COC with media, reduction of media corrosion and oxidation, and surface polarity. Moreover, the tribological, corrosion and surface properties of mixed Ar + N2 plasma treated media with 1.5 nm COCs are found to be comparable or better than ~2.7 nm thick conventional COC in commercial media.

A neutron activation technique for manganese measurements in humans.

Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Studies show that Mn metabolism is similar to that of iron, therefore, increased Mn levels in humans could interfere with the absorption of dietary iron leading to anemia. Also, excess exposure to Mn dust, leads to nervous system disorders similar to Parkinson's disease. Higher exposure to Mn is essentially related to industrial pollution. Thus, there is a benefit in developing a clean non-invasive technique for monitoring such increased levels of Mn in order to understand the risk of disease and development of appropriate treatments. To this end, the feasibility of Mn measurements with their minimum detection limits (MDL) has been reported earlier from the McMaster group. This work presents improvement to Mn assessment using an upgraded system and optimized times of irradiation and counting for induced gamma activity of Mn. The technique utilizes the high proton current Tandetron accelerator producing neutrons via the (7)Li(p,n)(7)Be reaction at McMaster University and an array of nine NaI (Tl) detectors in a 4 π geometry for delayed counting of gamma rays. The neutron irradiation of a set of phantoms was performed with protocols having different proton energy, current and time of irradiation. The improved MDLs estimated using the upgraded set up and constrained timings are reported as 0.67 µgMn/gCa for 2.3 MeV protons and 0.71 µgMn/gCa for 2.0 MeV protons. These are a factor of about 2.3 times better than previous measurements done at McMaster University using the in vivo set-up. Also, because of lower dose-equivalent and a relatively close MDL, the combination of: 2.0 MeV; 300 µA; 3 min protocol is recommended as compared to 2.3 MeV; 400 µA; 45 s protocol for further measurements of Mn in vivo.

Probing the role of an atomically thin SiNx interlayer on the structure of ultrathin carbon films.

Filtered cathodic vacuum arc (FCVA) processed carbon films are being considered as a promising protective media overcoat material for future hard disk drives (HDDs). However, at ultrathin film levels, FCVA-deposited carbon films show a dramatic change in their structure in terms of loss of sp3 bonding, density, wear resistance etc., compared to their bulk counterpart. We report for the first time how an atomically thin (0.4 nm) silicon nitride (SiNx) interlayer helps in maintaining/improving the sp3 carbon bonding, enhancing interfacial strength/bonding, improving oxidation/corrosion resistance, and strengthening the tribological properties of FCVA-deposited carbon films, even at ultrathin levels (1.2 nm). We propose the role of the SiNx interlayer in preventing the catalytic activity of Co and Pt in media, leading to enhanced sp3C bonding (relative enhancement~40%). These findings are extremely important in view of the atomic level understanding of structural modification and the development of high density HDDs.

Enhanced tribological, corrosion, and microstructural properties of an ultrathin (<2 nm) silicon nitride/carbon bilayer overcoat for high density magnetic storage.

An ultrathin bilayer overcoat of silicon nitride and carbon (SiNx/C) providing low friction, high wear resistance, and high corrosion resistance is proposed for future generation hard disk media. The 16 Å thick SiNx/C overcoat consists of an atomically thin SiNx underlayer (4 Å) and a carbon layer (12 Å), fabricated by reactive magnetron sputtering and filtered cathodic vacuum arc (FCVA), respectively. When compared with monolithic overcoats of FCVA-deposited carbon (16 Å) and sputtered SiNx (16 Å), the SiNx/C bilayer overcoat demonstrated the best tribological performance with a coefficient of friction < 0.2. Despite showing marginally less electrochemical corrosion protection than monolithic SiNx, its ability to protect the magnetic media from corrosion/oxidation was better than that of an ∼27 Å thick commercial hard disk overcoat and 16 Å thick monolithic FCVA-deposited carbon. From X-ray photoelectron spectroscopy and Raman spectroscopy analyses, it was found that the introduction of the 4 Å SiNx underlayer facilitated higher sp(3) hybridization within the carbon layer by acting as a barrier and promoted the formation of strong bonds at the SiNx/C and the SiNx/media interfaces by acting as an adhesion layer. The higher sp(3) carbon content is expected to improve the thermal stability of the overcoat, which is extremely important for future hard disk drives employing heat assisted magnetic recording (HAMR).

Nuclear deformation and neutron excess as competing effects for dipole strength in the pygmy region.

The electromagnetic dipole strength below the neutron-separation energy has been studied for the xenon isotopes with mass numbers A=124, 128, 132, and 134 in nuclear resonance fluorescence experiments using the γELBE bremsstrahlung facility at Helmholtz-Zentrum Dresden-Rossendorf and the HIγS facility at Triangle Universities Nuclear Laboratory Durham. The systematic study gained new information about the influence of the neutron excess as well as of nuclear deformation on the strength in the region of the pygmy dipole resonance. The results are compared with those obtained for the chain of molybdenum isotopes and with predictions of a random-phase approximation in a deformed basis. It turned out that the effect of nuclear deformation plays a minor role compared with the one caused by neutron excess. A global parametrization of the strength in terms of neutron and proton numbers allowed us to derive a formula capable of predicting the summed E1 strengths in the pygmy region for a wide mass range of nuclides.

Lateral displacement induced disorder in L1(0)-FePt nanostructures by ion-implantation.

Ion implantation is a promising technique for fabricating high density bit patterned media (BPM) as it may eliminate the requirement of disk planarization. However, there has not been any notable study on the impact of implantation on BPM fabrication of FePt, particularly at nano-scale, where the lateral straggle of implanted ions may become comparable to the feature size. In this work, implantation of antimony ions in patterned and unpatterned L1(0)-FePt thin films has been investigated. Unpatterned films implanted with high fluence of antimony exhibited reduced out-of-plane coercivity and change of magnetic anisotropy from perpendicular direction to film-plane. Interestingly, for samples implanted through patterned masks, the perpendicular anisotropy in the unimplanted region was also lost. This noteworthy observation can be attributed to the displacement of Fe and Pt atoms from the implantation sites to the unimplanted areas, thereby causing a phase disorder transformation from L1(0) to A1 FePt.

Quantization of Dextromethorphan and Levocetirizine in Combined Dosage form Using a Novel Validated RP-HPLC Method.

The present study reveals a simple isocratic RP-HPLC method for the simultaneous determination of dextromethorphan hydrobromide and levocetirizine dihydrochloride in a cough syrup. The separation of these compounds was achieved within 10 min on a Phenomenex (USA) C(18) analytical column, 250×4.0 mm i.d., using an isocratic mobile phase consisting of potassium dihydrogen phosphate buffer (pH 2.5) - acetonitrile- tetrahydrofuran (70:25:5, v/v/v). The analysis was performed at a flow rate of 1.2 ml/min and at a detection wavelength of 232 nm. Percentage recovery and RSD were 100.36% and 0.05% for levocetirizine dihydrochloride, 100.35% and 0.27% for dextromethorphan hydrobromide respectively. Quantification of the components in syrup formulation was calculated against the peak areas of freshly prepared standard solutions. The method was validated as per ICH guidelines.

Efficacy of less invasive posterior lumbar interbody fusion as revision surgery for patients with recurrent symptoms after discectomy.

Recurrence of back or leg pain after discectomy is a well-recognised problem with an incidence of up to 28%. Once conservative measures have failed, several surgical options are available and have been tried with varying degrees of success. In this study, 42 patients with recurrent symptoms after discectomy underwent less invasive posterior lumbar interbody fusion (LI-PLIF). Clinical outcome was measured using the Oswestry Disability Index (ODI), Short Form 36 (SF-36) questionnaires and visual analogue scales for back (VAS-BP) and leg pain (VAS-LP). There was a statistically significant improvement in all outcome measures (p < 0.001). The debate around which procedure is the most effective for these patients remains controversial. Our results show that LI-PLIF is as effective as any other surgical procedure. However, given that it is less invasive, we feel that it should be considered as the preferred option.

Ion-implantation studies on perpendicular media.

Magnetic and structural properties of ion implanted perpendicular recording media have been investigated. Effects of 12C+ ion implantation with the doses of 2 x 10(11), 10(13), 10(14) and 10(16) ions/cm2 in the magnetic recording layer of conventional granular and continuous perpendicular media are reported in this paper. Implantation with the highest fluence of 10(16) ions/cm2 resulted in change of the magnetization reversal mechanism, thereby reducing coercivity. In continuous media the implanted ions cause increase in pinning defects, leading to an increase in coercivity. In contrast, high dose was found to cause similar change in the crystallographic properties of both the granular and continuous media.

Seroprevalence of Toxoplasma gondii and Bartonella spp. antibodies in cats from Pennsylvania.

Toxoplasma gondii and Bartonella spp. are zoonotic pathogens of cats. In the present study, the prevalence of antibodies to T. gondii and Bartonella spp. were determined in sera from 210 domestic cats from Bensalem, Pennsylvania. Using a modified agglutination test, antibodies to T. gondii were found in 41 (19.5%) of the 210 cats with titers of 1:25 in 4, 1:50 in 9, 1:100 in 7, 1:200 in 3, 1:400 in 3, 1:800 in 5, 1:1,600 in 4, and 1:3,200 or higher in 6. For T. gondii, seroprevalence increased with age of the cat: 15 of 113 (13.2 %) were seropositive compared with 26 of 97 (26.7%) older than 11 mo. Of these 210 cats, 54 (25.7%) were positive for Bartonella spp. antibodies, with titers of 1:64 in 20, 1:128 in 21, 1:256 in 9, and 1:512 in 4. Seventeen cats had antibodies to both organisms. There was no correlation between T. gondii and Bartonella spp. seropositivity. Overall the seroprevalence of T. gondii antibodies in cats in this population is much lower compared with those reported in other localities in the United States and other countries.

The in vivo synthesis and accumulation of lectin in developing seeds of black gram (Vigna mungo L. Hepper).

Black gram (Vigna mungo L. Hepper) seed contains two D-galactose-specific lectin species, BGL-I and BGL-II, identified on the basis of elution from ion exchange column and immunochemical cross-reactivity. BGL-I consisted of two monomeric lectins, BGL-I-1 and BGL-1-2, of relative molecular weights 94 and 89 kDa, respectively. BGL-II is another monomeric lectin with a molecular weight of 83 kDa. The in vivo synthesis studies using pulse-chase experiment showed that BGL-II lectin was synthesized as early as 14 days after flowering (DAF). The 94-kDa BGL-I-1 lectin was synthesized around 17 DAF. There was no cotranslational or posttranslational modification of the lectin proteins. The amount of lectin in developing seeds was determined by radial immunodiffusion assay technique. The maximum amount of lectin per seed was found at 28 DAF.

Obstetric morbidity and socio-demographic factors in rural West Bengal, India.

The impact of selected socio-demographic factors on reported obstetric morbidity during antepartum and postpartum periods was studied through a cross-sectional retrospective survey carried out in rural areas of three districts of West Bengal, India. During their most recent live births, 56.6% of mothers reported at least one morbid condition. Mothers with higher levels of education reported fewer overall problems. Factors such as age and pregnancy order affect obstetric morbidity differently in different religious groups. More mothers reported postpartum than antepartum problems, and very few sought treatment. The present study provides an insight into various factors affecting obstetric morbidity in a developing country.

The effect of incentive spirometry on postoperative pulmonary complications: a systematic review.

OBJECTIVE: To systematically review the evidence examining the use of incentive spirometry (IS) for the prevention of postoperative pulmonary complications (PPCs). METHODS: We searched MEDLINE, CINAHL, HealthSTAR, and Current Contents databases from their inception until June 2000. Key terms included "incentive spirometry," "breathing exercises," "chest physical therapy," and "pulmonary complications." Articles were limited to human studies in English. A secondary search of the reference lists of all identified articles also was conducted. A critical appraisal form was developed to extract and assess information. Each study was reviewed independently by one of three pairs of group members. The pair then met to reach consensus before presenting the report to the entire review group for final agreement. RESULTS: The search yielded 85 articles. Studies dealing with the use of IS for preventing PPCs (n = 46) were accepted for systematic review. In 35 of these studies, we were unable to accept the stated conclusions due to flaws in methodology. Critical appraisal of the 11 remaining studies indicated 10 studies in which there was no positive short-term effect or treatment effect of IS following cardiac or abdominal surgery. The only supportive study reported that IS, deep breathing, and intermittent positive-pressure breathing were equally more effective than no treatment in preventing PPCs following abdominal surgery. CONCLUSIONS: Presently, the evidence does not support the use of IS for decreasing the incidence of PPCs following cardiac or upper abdominal surgery.

Octreotide therapy: a new horizon in treatment of iatrogenic chyloperitoneum.

Chyloperitoneum is a rare and challenging complication of abdominal surgery. We report a case of iatrogenic chyloperitoneum. Infusion of octreotide, a somatostatin analogue, together with total parenteral nutrition followed by medium chain triglyceride diet resulted in rapid resolution of chyloperitoneum. We believe this to be the first report of successful use of octreotide in iatrogenic chyloperitoneum in a child.

Characteristics of two major lectins from mungbean (Vigna radiata) seeds.

Two major lectins, MBL-I and MBL-II, were purified from Vigna radiata L. seeds using ion-exchange and gel filtration chromatography techniques. MBL-I was found to be a tetramer with native M.W. of 132 kDa and subunit M.W. of 33 kDa having alpha-galactosidase activity. MBL-II consisted of two monomeric lectins with M.W. of 94 kDa and 89 kDa which were associated mainly with beta-galactosidase activity. Both MBL-I and MBL-II are D-galactose-specific lectins.