Effect of gamma (γ-) radiation on the opto-structural and morphological properties of green synthesized BaO nanoparticles using Moringa Oleifera leaves.

In this current assessment, BaO synthesized from Moringa Oleifera leaves were irradiated using 0-75 kGy gamma radiation and investigated its physical impacts. The x-ray diffraction (XRD) data demonstrated the synthesis of tetragonal BaO, and no phase deviation was observed after irradiation. As doses are increased, the overall crystallite size were decreased due to an increase in defects and disorders. The tetragonal BaO was evident in Fourier transform infrared (FTIR) spectra prior to and following irradiation, while peak intensities and wavenumbers varied considerably. The as-prepared BaO showed a spherical shape morphology, and Field emission scanning electron microscopy (FESEM) indicated no vital deviations in it after irradiation. As irradiation shifts from 0 to 75 kGy, optical bandgap was increased from 4.55 to 4.93 eV, evaluated using Kubelka-Munk (K-M) equation from UV-vis-NIR spectrophotometer. Opto-electronic and photonic devices have challenges in extreme radiation conditions, such as space and nuclear environments. So, these assessments suggested that BaO can withstand high levels of gamma photon and could be a good option for photonic and optoelectronic instruments in an extreme gamma-ray exposed conditions.

Adjacent Mn site boosts photocatalytic hydrogen evolution of MnXCd1-XS solid solution through a dual-metal-site design.

CdS has emerged as a possible candidate for photocatalytic hydrogen generation. However, further improvement in the performance of the Cd metal site is challenging due to limited optimization space. To solve this limitation, in this work, the Mn-Cd dual-metal photocatalyst was synthesized by a one-step solvothermal method, and the effects of different proportions of bimetals on hydrogen production activity were systematically studied. The ingenious design of the bimetallic sites enhances the carrier separation efficiency and the built-in electric field intensity, which leads to significant improvement in the photocatalytic hydrogen production performance of MCS0.19. Density functional theory (DFT) calculations confirm that the introduction of the Mn element can drive electrons through the Fermi level, resulting in enhanced conductivity of the catalyst. Meanwhile, electron channels are built between Mn and S, which speeds up the rate of electron transfer and is conducive to improving hydrogen production activity. This work provides a technical-methodological entrance to improve the photocatalytic hydrogen production performance of dual-metal S solid solutions and also promises to open a novel approach to creating high-efficiency solid solution photocatalysts.

Immunotherapy for the Treatment of Squamous Cell Carcinoma: Potential Benefits and Challenges.

Melanoma and nonmelanoma skin cancers (NMSCs) are recognized as among the most common neoplasms, mostly in white people, with an increasing incidence rate. Among the NMSCs, squamous cell carcinoma (SCC) is the most prevalent malignancy known to affect people with a fair complexion who are exposed to extreme ultraviolet radiation (UVR), have a hereditary predisposition, or are immunosuppressed. There are several extrinsic and intrinsic determinants that contribute to the pathophysiology of the SCC. The therapeutic modalities depend on the SCC stages, from actinic keratosis to late-stage multiple metastases. Standard treatments include surgical excision, radiotherapy, and chemotherapy. As SCC represents a favorable tumor microenvironment with high tumor mutational burden, infiltration of immune cells, and expression of immune checkpoints, the SCC tumors are highly responsive to immunotherapies. Until now, there are three checkpoint inhibitors, cemiplimab, pembrolizumab, and nivolumab, that are approved for the treatment of advanced, recurrent, or metastatic SCC patients in the United States. Immunotherapy possesses significant therapeutic benefits for patients with metastatic or locally advanced tumors not eligible for surgery or radiotherapy to avoid the potential toxicity caused by the chemotherapies. Despite the high tolerability and efficiency, the existence of some challenges has been revealed such as, resistance to immunotherapy, less availability of the biomarkers, and difficulty in appropriate patient selection. This review aims to accumulate evidence regarding the genetic alterations related to SCC, the factors that contribute to the potential benefits of immunotherapy, and the challenges to follow this treatment regime.

Investigation on structure, thermodynamic and multifunctional properties of Ni-Zn-Co ferrite for Gd3+ substitution.

This study presents a modification of structure-dependent elastic, thermodynamic, magnetic, transport and magneto-dielectric properties of a Ni-Zn-Co ferrite tailored by Gd3+ substitution at the B-site replacing Fe3+ ions. The synthesized composition of Ni0.7Zn0.2Co0.1Fe2-x Gd x O4 (0 ≤ x ≤ 0.12) crystallized with a single-phase cubic spinel structure that belongs to the Fd3̄m space group. The average particle size decreases due to Gd3+ substitution at Fe3+. Raman and IR spectroscopy studies illustrate phase purity, lattice dynamics with cation disorders and thermodynamic conditions inside the studied samples at room temperature (RT = 300 K). Ferromagnetic to paramagnetic phase transition was observed in all samples where Curie temperature (T C) decreases from 731 to 711 K for Gd3+ substitution in Ni-Zn-Co ferrite. In addition, Gd3+ substitution reinforces to decrease the A-B exchange interaction. Temperature-dependent DC electrical resistivity (ρ DC) and temperature coefficient of resistance (TCR) have been surveyed with the variation of the grain size. The frequency-dependent dielectric properties and electric modulus at RT for all samples were observed from 20 Hz to 100 MHz and the conduction relaxation processes were found to spread over an extensive range of frequencies with the increase in the amount of Gd3+ in the Ni-Zn-Co ferrite. The RLC behavior separates the zone of frequencies ranging from resistive to capacitive regions in all the studied samples. Finally, the matching impedance (Z/η 0) for all samples was evaluated over an extensive range of frequencies for the possible miniaturizing application.

TB prevalence among patients with diabetes in Bangladesh.

OBJECTIVE: 1) To assess the prevalence of TB among patients with diabetes mellitus (DM) attending diabetic care centres in Bangladesh, and 2) to compare TB- and DM-related sociodemographic and other factors in diabetic patients who had TB and those who did not.METHODS: This cross-sectional study was conducted from 1 June 2019 to 31 March 2020 in 108 centres of the Diabetic Association of Bangladesh (BADAS), with a sample size of 3,649 patients with DM. Data were collected by face-to-face interview using semi-structured questionnaire from each patient/guardian. Other ethical issues were also maintained.RESULTS: Out of 3,649 patients with DM, 676 presumptive TB cases were identified and tested; from them, 85 patients were detected as TB cases. Another 39 patients were already diagnosed and on anti-TB medication. Prevalence of TB among patients with DM attending diabetic care centres was 3.4%. Prevalence was higher in female than male (4.0% vs 2.6%). Underweight (9.0%) patients and patients having diabetes for more than 10 years (7.1%) had a higher prevalence of TB.CONCLUSION: TB prevalence was over 3% among study population with DM. Periodic screening and active case finding among DM patients should be strengthened to reduce the risk of TB infection among DM patients.

National Clinical Guidance for the Management of Cardiovascular Intervention in the COVID-19 Pandemic: From Bangladesh Society of Cardiovascular Interventions (BSCI).

Since the first recorded case of SARS-CoV-2 in Bangladesh on 8th March 2020, COVID-19 has spread widely through different regions of the country, resulting in a necessity to re-evaluate the delivery of cardiovascular services, particularly procedures pertaining to interventional cardiology in resource-limited settings. Given its robust capacity for human-to-human transmission and potential of being a nosocomial source of infection, the disease has specific implications on healthcare systems and health care professionals faced with performing essential cardiac procedures in patients with a suspected or confirmed diagnosis of COVID-19. The limited resources in terms of cardiac catheterization laboratories that can be designated to treat only COVID positive patients are further compounded by the additional challenges of unavailability of widespread rapid testing on-site at tertiary cardiac hospitals in Bangladesh. This document prepared for our nation by the Bangladesh Society of Cardiovascular Interventions (BSCI) is intended to serve as a clinical practice guideline for cardiovascular health care professionals, with a focus on modifying standard practice of care during the COVID-19 pandemic, in order to ensure continuation of adequate and timely treatment of cardiovascular emergencies avoiding hospital-based transmission of SARS-COV-2 among healthcare professionals and the patients. This is an evolving document based on currently available global data and is tailored to healthcare systems in Bangladesh with particular focus on, but not limited to, invasive cardiology facilities (cardiac catheterization, electrophysiology & pacing labs). This guideline is limited to the provision of cardiovascular care, and it is expected that specific targeted pharmaco-therapeutics against SARS-CoV-2 be prescribed as stipulated by the National Guidelines on Clinical Management of Corona virus Disease 2019 (COVID-19) published by the Director General of Health Services, Ministry of Health and Family Welfare of Bangladesh.

Boosting landfill gas production from lignin-containing wastes via termite hindgut microorganism.

Lignocellulose comprises a significant portion of municipal solid waste (MSW) - 40-70% in developed countries, including paper, wood, and yard waste. Cellulose and hemicellulose are often shielded by lignin, posing a barrier to waste decomposition and landfill gas generation. Unfortunately, lignin is resistant to microbial degradation under low-oxygen conditions that normally occur in MSW landfills. The bacterium strain TAV5, microaerophilic and member of phylum Verrucomicrobia, isolated from the hindgut of the Reticulitermes flavipes termite, the most widely distributed subterranean termite in North America. Its genome contains genes associated with methylotrophic competency which code for enzymes that structurally modify lignin. The overall goal of this research was to use TAV5 to modify lignin and boost methane production from MSW. Batch-scale reactors (125 mL) were filled with paper, yard, or wood waste, and four ratios of mixed of waste. Reactors were seeded with different ratios of TAV5 to anaerobic digester (AD) microorganisms (representing landfill anaerobic microorganisms). Based on batch tests, optimal ratios of TAV5 to AD microorganisms were used to seed wastes (mixed, yard, and wood) in 6-gallon reactors. Addition of TAV5 increased methane production from mixed waste, yard waste, and wood, by 49%, 34%, and 297%, respectively. TAV5 decreased acid soluble lignin by 7-39%, depending on waste type. TAV5 grown under aerobic conditions and room temperature (not requiring a heated anaerobic chamber) was found to remain viable and increase methane production under low-level oxygen conditions (1-2%). This finding will potentially lessen costs for growing large volumes of it for seeding landfills.

Separation detection of hemoglobin and glycated hemoglobin fractions in blood using the electrochemical microfluidic channel with a conductive polymer composite sensor.

Separation and detection of hemoglobin (Hb) and glycated hemoglobin fractions (HbA1c, HbAld1+2, HbAle, HbAld3a, HbAla+b, HbA2, and HbAld3b) was performed using an electrochemical AC field modulated separation channel (EMSC) coupled with a sensor probe. The sensor was fabricated based on immobilization of a redox mediator on the poly(2,2':5',5″-terthiophene-3'-p-benzoic acid, pTTBA) and N,S-doped porous carbon (NSPC) nanocomposite. The different types of catalytic redox mediators such as Nile Blue (NB), toluidine blue O (TBO), and Neutral Red (NR) were evaluated to achieve the efficient detection. Of these, the NB-based sensor showed the best analytical signal for Hb and HbA1c, thus it was characterized using various electrochemical and surface analysis methods. After that, the sensor was coupled with the EMSC to achieve the separation detection of the Hb family. The frequency and amplitude of the AC electrical field applied onto the EMSC walls were the main driving forces for the separation and sensitive detection of the analytes. Under optimized conditions, linear dynamic ranges for Hb and HbA1c among their fractions were obtained between 1.0 × 10-6 to 3.5 mM and 3.0 × 10-6 to 0.6 mM with the detection limit of 8.1 × 10-7 ± 3.0 × 10-8 and 9.2 × 10-7 ± 5 × 10-8 mM, respectively. Interference effects of other biomolecules were also investigated and the clinical applicability of the device was evaluated by the determination of total Hb and % HbA1c in real human blood samples.

Status of Hearing Impairment among Handloom Workers in Tangail District of Bangladesh.

Industrial noise is one of the major sources of noise pollution. Handloom industry is the biggest handicraft industry in our country; it is the second largest source of rural employment after agriculture. The workers of the handloom industry worked within excessive level of sound. This cross-sectional study was an attempt to see the status of hearing impairment among handloom worker at Tangail District, Bangladesh from August 2016 to December 2016. A total 180 handloom workers were included in this current study. All the respondents were male as handloom work is a strenuous work. The mean age of respondents was 38.18±11.529 years where most of the respondents were of middle age group (21-50) year's age group. Among the participants less than one-fourth was illiterate and rest had primary to secondary level of education. The average income of handloom workers was 13805.56±2764.696 BDT per month. Handloom workers spend average 10 hour for working per day. They were exposed to sound beyond NIOSH recommendation (70-83 dB around handloom machines and 80-90 dB around power loom machines). By self-assessment hearing impairment perception 76.7% participants reported that they had hearing problem. Based on the interpretation of Rinne, Webers and ABC test data indicate that among the respondents around 32.2% were identified with bilateral sensorineural hearing impairment and of them through Pure tone audiometry (PTA) around half were diagnosed as suffering from moderate to severe Noise induced hearing loss (NIHL). Using personal protective measure like ear muffle/ear musk has been recommended.

Room-temperature ferromagnetism in Ni(ii)-chromia based core-shell nanoparticles: experiment and first principles calculations.

We have synthesized bimagnetic core-shell nanoparticles containing a first-of-its-kind Ni(ii)-chromia nanophase shell and a well-defined, epitaxial core-shell interface. Magnetic measurements reveal a substantial coercivity of the nanoparticles and a significant exchange bias effect between the antiferromagnetic chromia core and the ferromagnetic Ni(ii)-chromia shell at low temperatures. The ferromagnetism and a weak exchange bias effect are found to persist to room temperature in the core-shell nanoparticles of ∼57 nm average size. Our first principles Density Functional Theory (DFT) calculations confirm that the novel corundum-structured Ni(ii)-chromia phase has an equilibrium cluster-localized ferromagnetic spin configuration. In addition, the DFT-based calculations show that the Ni(ii)-chromia phase is a Mott-Hubbard insulator, with a narrowed energy band gap and increased covalent bonding due to strong hybridization between Ni 3d and O 2p levels in the upper portion of the valence band and within the band gap region. The antiferromagnetic, ferromagnetic and magnetoelectric properties of our core-shell nanoparticles make these well suited for patterned recording media and biomedical applications.

Estimating methane emissions from landfills based on rainfall, ambient temperature, and waste composition: The CLEEN model.

Accurately estimating landfill methane emissions is important for quantifying a landfill's greenhouse gas emissions and power generation potential. Current models, including LandGEM and IPCC, often greatly simplify treatment of factors like rainfall and ambient temperature, which can substantially impact gas production. The newly developed Capturing Landfill Emissions for Energy Needs (CLEEN) model aims to improve landfill methane generation estimates, but still require inputs that are fairly easy to obtain: waste composition, annual rainfall, and ambient temperature. To develop the model, methane generation was measured from 27 laboratory scale landfill reactors, with varying waste compositions (ranging from 0% to 100%); average rainfall rates of 2, 6, and 12 mm/day; and temperatures of 20, 30, and 37°C, according to a statistical experimental design. Refuse components considered were the major biodegradable wastes, food, paper, yard/wood, and textile, as well as inert inorganic waste. Based on the data collected, a multiple linear regression equation (R(2)=0.75) was developed to predict first-order methane generation rate constant values k as functions of waste composition, annual rainfall, and temperature. Because, laboratory methane generation rates exceed field rates, a second scale-up regression equation for k was developed using actual gas-recovery data from 11 landfills in high-income countries with conventional operation. The Capturing Landfill Emissions for Energy Needs (CLEEN) model was developed by incorporating both regression equations into the first-order decay based model for estimating methane generation rates from landfills. CLEEN model values were compared to actual field data from 6 US landfills, and to estimates from LandGEM and IPCC. For 4 of the 6 cases, CLEEN model estimates were the closest to actual.

The expression pattern of microRNAs in granulosa cells of subordinate and dominant follicles during the early luteal phase of the bovine estrous cycle.

This study aimed to investigate the miRNA expression patterns in granulosa cells of subordinate (SF) and dominant follicle (DF) during the early luteal phase of the bovine estrous cycle. For this, miRNA enriched total RNA isolated from granulosa cells of SF and DF obtained from heifers slaughtered at day 3 and day 7 of the estrous cycle was used for miRNAs deep sequencing. The results revealed that including 17 candidate novel miRNAs, several known miRNAs (n = 291-318) were detected in SF and DF at days 3 and 7 of the estrous cycle of which 244 miRNAs were common to all follicle groups. The let-7 families, bta-miR-10b, bta-miR-26a, bta-miR-99b and bta-miR-27b were among abundantly expressed miRNAs in both SF and DF at both days of the estrous cycle. Further analysis revealed that the expression patterns of 16 miRNAs including bta-miR-449a, bta-miR-449c and bta-miR-222 were differentially expressed between the granulosa cells of SF and DF at day 3 of the estrous cycle. However, at day 7 of the estrous cycle, 108 miRNAs including bta-miR-409a, bta-miR-383 and bta-miR-184 were differentially expressed between the two groups of granulosa cell revealing the presence of distinct miRNA expression profile changes between the two follicular stages at day 7 than day 3 of the estrous cycle. In addition, unlike the SF, marked temporal miRNA expression dynamics was observed in DF groups between day 3 and 7 of the estrous cycle. Target gene prediction and pathway analysis revealed that major signaling associated with follicular development including Wnt signaling, TGF-beta signaling, oocyte meiosis and GnRH signaling were affected by differentially expressed miRNAs. Thus, this study highlights the miRNA expression patterns of granulosa cells in subordinate and dominant follicles that could be associated with follicular recruitment, selection and dominance during the early luteal phase of the bovine estrous cycle.

Glutathione-binding site of a bombyx mori theta-class glutathione transferase.

The glutathione transferase (GST) superfamily plays key roles in the detoxification of various xenobiotics. Here, we report the isolation and characterization of a silkworm protein belonging to a previously reported theta-class GST family. The enzyme (bmGSTT) catalyzes the reaction of glutathione with 1-chloro-2,4-dinitrobenzene, 1,2-epoxy-3-(4-nitrophenoxy)-propane, and 4-nitrophenethyl bromide. Mutagenesis of highly conserved residues in the catalytic site revealed that Glu66 and Ser67 are important for enzymatic function. These results provide insights into the catalysis of glutathione conjugation in silkworm by bmGSTT and into the metabolism of exogenous chemical agents.

Evaluation of serum lipid profile in patients with hypertension living in a coastal region of Bangladesh.

Serum lipid levels are greatly controlled by genetic and environmental factors. When investigating the relationship between lipid disturbances and hypertension it is necessary to use local data on blood lipid profile in each region. Unfortunately, there is no literature reporting the lipid profile in hypertensive patients in coastal region of Bangladesh. The present study was conducted as a case-control study with 100 hypertensive patients as cases and equal number of normotensive individuals as controls. Socio-demographic, anthropometric and clinical data of both patients and controls were collected. Serum lipid parameters were analyzed biochemically. Independent sample t-test, Chi-Square test and Pearson's correlation test were done for the statistical analysis using the statistical software package SPSS. Our study found that serum total cholesterol (TC), triglyceride (TG), LDL, VLDL, TC/HDL, LDL/HDL were significantly higher (p<0.05) whereas the level of HDL cholesterol was significantly lower in hypertensive patients as compared to control subjects (p<0.05). Pearson's correlation analysis reveals that HDL cholesterol was inversely correlated with systolic and diastolic blood pressure in both patient and control groups. But serum TC, TG, LDL and HDL cholesterol were directly correlated with systolic and diastolic blood pressure in both groups. This study explored that hypertensive patients have higher level of TC, TG, LDL and VLDL cholesterol but lower level of HDL cholesterol than the normotensive subjects. Routine investigation of lipid profile in hypertensive patients may help to prevent further aggravation and risks of coronary artery diseases.

Nature of weak magnetism in SrTiO3/LaAlO3 multilayers.

We report the observation of weak magnetism in superlattices of LaAlO(3)/SrTiO(3) using ß-detected nuclear magnetic resonance. The spin lattice relaxation rate of ^{8}Li in superlattices with a spacer layers of 8 and 6 unit cells of LaAlO(3) exhibits a strong peak near ~35 K, whereas no such peak is observed in a superlattice with spacer layer thickness of 3 unit cells. We attribute the observed temperature dependence to slowing down of weakly coupled electronic moments at the LaAlO(3)/SrTiO(3) interface. These results show that the magnetism at the interface depends strongly on the thickness of the spacer layer, and that a minimal thickness of ~4-6 unit cells is required for the appearance of magnetism. A simple model is used to determine that the observed relaxation is due to small fluctuating moments (~0.002µ(B)) in the two samples with a larger LaAlO(3) spacer thickness.

Tubercular lymphadenitis - diagnostic evaluation.

Tuberculosis is one the commonest disease affecting peripheral lymph node and cervical tubercular lymphadenitis are frequently encountered in Otolaryngological practice. Three hundred fifty six (356) cases of Fine Needle Aspiration for Cytology (FNAC) positive tubercular lymphadenitis were studied from January 2006 to December 2008. FNAC positive but histopathologically negative cases were excluded from the study. Among 356 cases of FNAC positive cervical lymphadenopathy 300 cases (84.27%) were confirmed tuberculosis on histopathological examination. Remaining 50 cases (15.73%) were diagnosed as nontubercular lymphadenitis where nonspecific lymphadenitis was the commonest finding 34(9.55%) followed by metastatic carcinoma 7(1.97%), lymphoma 6(1.08%), Kikuchiz's disease 6(1.08%), Kala-Azar 2(0.56%) & Leukemia 1(0.28%). Most of the patients presented with only multiple lymph node swelling with other symptoms, such as fever 18(5.06%), pain (15.7%), tenderness 53(14.88%), weight loss 29(8.14%), anorexia 33(9.26%). Following observations are evident from this study: i) Disease is comparatively common between 12-35 years ii) Multiple matted/discrete lymph nodes are the earliest presentation iii) Multiple lymph node is the most consistent finding for clinical diagnosis. iv) Very few patients have constitutional symptoms v) Suppuration with or without abscess formation although confirms the diagnosis even then certainty is very essential. Though the evidence of cervical tuberculosis was thought to be decreasing in developing countries the real picture seems to be different. Random survey among the whole population was not done in any country rather hospital based laboratory research was made.

Analysis of arsenic concentrations and correlation in water, soil and aurum by neutron activation analysis technique: a case study in Bagerhat, Bangladesh.

Arsenic concentrations were measured in water, soil and arum (vegetables) samples using the Neutron Activation Analysis method and a correlation between arsenic concentrations in the samples was investigated. The case study at Bagerhat, Bangladesh revealed that almost all the water samples were contaminated by a hazardous level of arsenic that exceeding the World Health Organization recommended value of 0.05 mg/L for Bangladesh. Arsenic concentration of all the water samples ranged from 0.09 to 0.87 mg/L. The concentrations in soil and aurum samples were found to be in the range of 2.22-35.21 and 0.07-0.73 mg/kg, respectively. A positive correlation between arsenic concentrations in soil and water samples was observed. Aurum sample was found to be contaminated by arsenic to a harmful level if the corresponding water sample was also highly contaminated.

Procedural sedation in children for magnetic resonance imaging--comparison between ketamine diazepam combination with midazolam fentanyl combination.

A deeper level of sedation by an anaesthesiologist is requirement for magnetic resonance imaging (MRI) in paediatric populations and sedation of children is different from sedation of adults. The purpose of the study was to compare the efficacy, safety, tolerability and cost effectiveness of ketamine, diazepam combination to midazolam, fentanyl combination for sedation of children during MRI. One hundred twenty children of both sex, age between 1-10 years, American Society of Anesthesiologist (ASA) physical status I and II were distributed into two groups. Group A (n=60) were sedated with 1.5 mg/kg body weight ketamine and 0.1 mg/kg body weight diazepam intravenously. Group B (n=60) were sedated with midazolam 0.05 mg/kg bodyweight and fentanyl 1 microg/kg body weight intravenously. Both groups showed satisfactory sedating condition for MRI. Incidences of side effects of drug regimens during sedation and recovery were recorded in both groups; those were transient and minor inconveniences. Pulse, blood pressure and respiration were within normal range in both groups. Mean procedure time was almost same in both groups and mean recovery time was more in group A than group B and the difference was statistically significant (p<0.05). Every child of both groups was discharged to home. Sedation regimen of group B found 5 times more costly than group A. Both the regimens were found safe and effective for paediatric sedation during MRI but ketamine, diazepam combination found more cost effective which, is a considerable matter in Bangladesh.

Proximal magnetometry in thin films using betaNMR.

Low energy ion implantation of hyperpolarized radioactive magnetic resonance probes allows the NMR study of thin film heterostructures by enabling depth-resolved measurements on a nanometer lengthscale. By stopping the probe ions in a layer adjacent to a layer of interest, it is possible to study magnetic fields proximally. Here we show that, in the simplest case of a uniformly magnetized layer, this yields an unperturbed in situ frequency reference. We also discuss demagnetization contributions to measured shifts for this case. With a simple illustrative calculation, we show how a nonuniformly magnetized layer causes a strongly depth-dependent line broadening in an adjacent layer. We then give some experimental examples of resonance line broadening in heterostructures.

Local magnetic properties of a monolayer of Mn12 single molecule magnets.

The magnetic properties of a monolayer of Mn12 single molecule magnets grafted onto a silicon (Si) substrate have been investigated using depth-controlled beta-detected nuclear magnetic resonance. A low-energy beam of spin-polarized radioactive 8Li was used to probe the local static magnetic field distribution near the Mn12 monolayer in the Si substrate. The resonance line width varies strongly as a function of implantation depth as a result of the magnetic dipolar fields generated by the Mn12 electronic magnetic moments. The temperature dependence of the line width indicates that the magnetic properties of the Mn12 moments in this low-dimensional configuration differ from bulk Mn12.