Enhanced Widefield Quantum Sensing with Nitrogen-Vacancy Ensembles Using Diamond Nanopillar Arrays

Surface micro- and nano-patterning techniques are often employed to enhance the optical interface to single photoluminescent emitters in diamond, but the utility of such surface structuring in applications requiring ensembles of emitters is still open to investigation. Here, we demonstrate scalable and fault-tolerant fabrication of closely packed arrays of fluorescent diamond nanopillars, each hosting its own dense, uniformly bright ensemble of near-surface nitrogen-vacancy centers. We explore the optimal sizes for these structures and realize enhanced spin and photoluminescence properties resulting in a 4.5 times increase in optically detected magnetic resonance sensitivity when compared to unpatterned surfaces. Utilizing the increased measurement sensitivity, we image the mechanical stress tensor in each diamond pillar across the arrays and show that the fabrication process has a negligible impact on in-built stress compared to the unpatterned surface. Our results represent a valuable pathway toward future multimodal and vector-resolved imaging studies, for instance in biological contexts.

Angiotensin-Converting Enzyme Gene Polymorphism and Erythropoietin Requirement

Objectives

To study the effect of angiotensin-converting enzyme (ACE) polymorphisms II, ID, and DD on erythropoietin (EPO) requirement in patients on continuous ambulatory peritoneal dialysis (CAPD) therapy.

Design

Retrospective observational study.

Setting

CAPD Unit, Royal London/St. Bartholomews Hospital, London, UK.

Patients

46 patients on the transplant waiting list (age 20 – 70 years), on CAPD therapy for an average of 28 months, seen consecutively over a period of 3 months in the outpatients department.

Main Outcome Measures

Primary end point: EPO dose requirement in different ACE genotypes. Secondary end points: C-reactive protein, ferritin, parathyroid hormone, Kt/V, duration of dialysis, folate, cause of renal failure, and whether or not patients were on ACE inhibitor therapy.

Results

There was a statistically significant difference ( p < 0.05) in EPO requirement in the II/ID group compared to the DD group. The mean ± standard error of EPO for the II/ID group was 144 ± 15 U/kg/week, and for the DD group, 87 ± 9 U/kg/ week. The difference in EPO requirement could not be explained by age, C-reactive protein, ferritin, parathyroid hormone, Kt/V, duration of dialysis, folate, cause of renal failure, or whether or not patients were on ACE inhibitor therapy.

Conclusion

In CAPD patients, ACE genotype has predictive value when determining the EPO dosage, as the II/ID genotype may be associated with a suboptimal response.

The Effect of Proinflammatory Cytokine Gene and Angiotensin-Converting Enzyme Polymorphisms on Erythropoietin Requirements in Patients on Continuous Ambulatory Peritoneal Dialysis

Background

The correction of anemia by recombinant human erythropoietin (rHuEPO) improves quality of life and prolongs life in end-stage renal failure. rHuEPO requirements for an individual are determined by a range of factors, including iron deficiency and inflammation. Single nucleotide polymorphisms in the promoter sequence of several proinflammatory cytokines have been shown, in different fields of medicine, to influence the cytokine response to different stimuli, with effects on clinical outcome.

Methods

The angiotensin-converting enzyme (ACE) insertion/deletion polymorphism and polymorphisms in the promoter regions of the genes for tumor necrosis factor alpha (-308 A/G), interleukin-6 (-174 G/C), and interferon gamma were examined for their association with rHuEPO requirements in 112 patients on continuous ambulatory peritoneal dialysis (CAPD). Genomic DNA was extracted from peripheral blood leukocytes and genotyping performed with ARMS-PCR methodology, with sequence-specific primers. We examined rHuEPO requirements and C-reactive protein at baseline and during a 6-month study period.

Results

We found no significant effect of proinflammatory cytokine polymorphisms on rHuEPO responsiveness. However, throughout the study, we observed that there was a significantly higher rHuEPO requirement in the II and ID ACE genotypes compared with the DD group, which remained an independent association following multivariate analysis.

Conclusions

ACE insertion/deletion polymorphism may determine rHuEPO responsiveness in CAPD patients and should be considered in relative rHuEPO resistance.

Microscopic Imaging of the Stress Tensor in Diamond Using in Situ Quantum Sensors

The precise measurement of mechanical stress at the nanoscale is of fundamental and technological importance. In principle, all six independent variables of the stress tensor, which describe the direction and magnitude of compression/tension and shear stress in a solid, can be exploited to tune or enhance the properties of materials and devices. However, existing techniques to probe the local stress are generally incapable of measuring the entire stress tensor. Here, we make use of an ensemble of atomic-sized in situ strain sensors in diamond (nitrogen-vacancy defects) to achieve spatial mapping of the full stress tensor, with a submicrometer spatial resolution and a sensitivity of the order of 1 MPa (10 MPa) for the shear (axial) stress components. To illustrate the effectiveness and versatility of the technique, we apply it to a broad range of experimental situations, including mapping the stress induced by localized implantation damage, nanoindents, and scratches. In addition, we observe surprisingly large stress contributions from functional electronic devices fabricated on the diamond and also demonstrate sensitivity to deformations of materials in contact with the diamond. Our technique could enable in situ measurements of the mechanical response of diamond nanostructures under various stimuli, with potential applications in strain engineering for diamond-based quantum technologies and in nanomechanical sensing for on-chip mass spectroscopy.

Fundamental crystal field excitations in magnetic semiconductor SnO2: Mn, Fe, Co, Ni

Directly measuring elementary electronic excitations in dopant 3d metals is essential to understanding how they function as part of their host material. Through calculated crystal field splittings of the 3d electron band it is shown how transition metals Mn, Fe, Co, and Ni are incorporated into SnO2. The crystal field splittings are compared to resonant inelastic X-ray scattering (RIXS) experiments, which measure precisely these elementary dd excitations. The origin of spectral features can be determined and identified via this comparison, leading to an increased understanding of how such dopant metals situate themselves in, and modify the host's electronic and magnetic properties; and also how each element differs when incorporated into other semiconducting materials. We found that oxygen vacancy formation must not occur at nearest neighbour sites to metal atoms, but instead must reside at least two coordination spheres beyond. The coordination of the dopants within the host can then be explicitly related to the d-electron configurations and energies. This approach facilitates an understanding of the essential link between local crystal coordination and electronic/magnetic properties.

HLA polymorphism in Sudanese renal donors

The main objective of this study is to provide a database for renal transplantation in Sudan and to determine the HLA antigens and haplotype frequencies (HFs) in the study subjects. HLA typing was performed using the complement-dependant lymphocytotoxicity test in 250 unrelated healthy individuals selected as donors in the Sudanese Renal Transplantation Program. Considerable polymorphism was observed at each locus; A2 (0.28), A30 (0.12), A3 (0.09), A24 (0.09), A1 (0.09), and A68 (0.06) were the most frequent antigens in the A locus, while B51 (0.092), B41 (0.081), B39 (0.078), B57 (0.060), B35 (0.068), B 50 (0.053) and B 52 (0.051) were the most common B locus antigens. DR13 (0.444) and DR15 (0.160) showed the highest antigen frequencies (AFs) in the DR locus. In the DQ locus, DQ1 showed the highest gene frequency (0.498), while DQ2 and DQ3 AFs were (0.185) and (0.238), respectively. The most common HLA-A and -B haplotypes in positive linkage disequilibrium were A24, B38; A1, B7; and A3, B52. The common HLA-A and -B HFs in positive linkage disequilibrium in the main three tribe-stocks of the study subjects (Gaalia, Nile Nubian and Johyna) were A24, B38 for Gaalia; A24, B38 and A2, B7 for Johyna; and A2, B64 and A3, B53 for Nile Nubian. These results suggest that both class I and class II polymorphisms of the study subjects depict considerable heterogeneity, which reflects recent admixture of this group with neighboring Arabs and African populations.

Serial transplantation of mismatched donor hematopoietic cells between HLA-identical sibling pairs with congenital immunodeficiency: in vivo tolerance permits rapid immune reconstitution following T-replete transplantation without GVHD in the secondary recipient

We report serial transplantation procedures in 2 sets of brothers with X-linked primary immunodeficiency. The first boy in each family received a T-cell–depleted transplant from a mismatched donor. The recipients then acted as donors for T-replete transplantation of the “tolerized” graft into their HLA-identical brothers with the same disorder. Immune reconstitution was noted to occur at a significantly faster rate in the secondary recipients, and without the occurrence of graft-versus-host disease (GVHD), despite the presence of donor cells mismatched for 1 to 3 HLA antigens. This serial transplantation technique allows the primary recipient of HLA-mismatched donor cells to act as a functionally “HLA-matched” donor for subsequent affected siblings, and should be considered as a therapeutic option in families with congenital disorders.

The effect of proinflammatory cytokine gene and angiotensin-converting enzyme polymorphisms on erythropoietin requirements in patients on continuous ambulatory peritoneal dialysis

BACKGROUND

The correction of anemia by recombinant human erythropoietin (rHuEPO) improves quality of life and prolongs life in end-stage renal failure. rHuEPO requirements for an individual are determined by a range of factors, including iron deficiency and inflammation. Single nucleotide polymorphisms in the promoter sequence of several proinflammatory cytokines have been shown, in different fields of medicine, to influence the cytokine response to different stimuli, with effects on clinical outcome.

METHODS

The angiotensin-converting enzyme (ACE) insertion/deletion polymorphism and polymorphisms in the promoter regions of the genes for tumor necrosis factor alpha (-308 A/G), interleukin-6 (-174 G/C), and interferon gamma were examined for their association with rHuEPO requirements in 112 patients on continuous ambulatory peritoneal dialysis (CAPD). Genomic DNA was extracted from peripheral blood leukocytes and genotyping performed with ARMS-PCR methodology, with sequence-specific primers. We examined rHuEPO requirements and C-reactive protein at baseline and during a 6-month study period.

RESULTS

We found no significant effect of proinflammatory cytokine polymorphisms on rHuEPO responsiveness. However, throughout the study, we observed that there was a significantly higher rHuEPO requirement in the II and ID ACE genotypes compared with the DD group, which remained an independent association following multivariate analysis.

CONCLUSIONS

ACE insertion/deletion polymorphism may determine rHuEPO responsiveness in CAPD patients and should be considered in relative rHuEPO resistance.

Pretransplantation levels of C-reactive protein predict all-cause and cardiovascular mortality, but not graft outcome, in kidney transplant recipients

BACKGROUND

Chronic inflammation, the common pathway that leads to cardiovascular disease and chronic allograft nephropathy after transplantation, is prevalent in patients with end-stage renal failure. We set out to investigate the hypothesis that enhanced pretransplantation C-reactive protein (CRP) levels and Chlamydia seropositivity, both markers of an altered immune response, would predict graft failure and mortality in patients receiving renal replacement therapy.

METHODS

A retrospective study of 115 patients, based on CRP levels in pretransplantation serum (group 1, 0 to 5 mg/L; group 2, 5 to 10 mg/L; group 3, >10 mg/L), were investigated for the following end points: transplant rejection, graft failure, and all-cause and cardiovascular mortality.

RESULTS

There were no correlations between CRP levels or Chlamydia seropositivity with respect to rejection rates or graft failure. Furthermore, there was no relationship between Chlamydia seropositivity and survival. All-cause and cardiovascular mortality were significantly greater in patients with CRP levels greater than 10 mg/L and 5 to 10 mg/L compared with those with CRP levels less than 5 mg/L. All-cause mortality rates were 5% in the 0-to-5-mg/L group, 20% in the 5-to-10-mg/L group, and 44% in the greater-than-10-mg/L group. With regard to cardiovascular mortality, death rates were 0% in the 0-to-5-mg/L group, 10% in the 5-to-10-mg/L group, and 22% in the greater-than-10-mg/L group. Univariate analysis of cardiovascular mortality and covariates showed a significant relationship with age (relative risk [RR], 1.07; P < 0.05), diabetes (RR, 5.6; P < 0.05), aspirin intake (RR, 0.2; P < 0.05), antihypertensive therapy (RR, 0.02; P < 0.05), and CRP level (RR, 11; P < 0.05), but CRP level remained the only significant predictor (RR, 1.19; P < 0.05) on multivariate analysis.

CONCLUSION

Pretransplantation CRP level is independently associated with all-cause and cardiovascular mortality in our cohort of transplant recipients and may be a useful predictive marker in the follow-up of posttransplantation patients.

Angiotensin-converting enzyme gene polymorphism and erythropoietin requirement

OBJECTIVES

To study the effect of angiotensin-converting enzyme (ACE) polymorphisms II, ID, and DD on erythropoietin (EPO) requirement in patients on continuous ambulatory peritoneal dialysis (CAPD) therapy.

DESIGN

Retrospective observational study.

SETTING

CAPD Unit, Royal London/St. Bartholomews Hospital, London, UK.

PATIENTS

46 patients on the transplant waiting list (age 20-70 years), on CAPD therapy for an average of 28 months, seen consecutively over a period of 3 months in the outpatients department.

MAIN OUTCOME MEASURES

Primary end point: EPO dose requirement in different ACE genotypes. Secondary end points: C-reactive protein, ferritin, parathyroid hormone, Kt/V, duration of dialysis, folate, cause of renal failure, and whether or not patients were on ACE inhibitor therapy.

RESULTS

There was a statistically significant difference (p < 0.05) in EPO requirement in the II/ID group compared to the DD group. The mean +/- standard error of EPO for the II/ID group was 144 +/- 15 U/kg/week, and for the DD group, 87 +/- 9 U/kg/week. The difference in EPO requirement could not be explained by age, C-reactive protein, ferritin, parathyroid hormone, Kt/V, duration of dialysis, folate, cause of renal failure, or whether or not patients were on ACE inhibitor therapy.

CONCLUSION

In CAPD patients, ACE genotype has predictive value when determining the EPO dosage, as the III/ID genotype may be associated with a suboptimal response.

Parasitic infection with Trichuris trichiura influences plasma levels of soluble HLA class I

High levels of sHLA-I (soluble HLA--class I) have been correlated with rejection episodes in solid organ transplant recipients and with graft versus host disease in bone marrow recipients. Studies of human infection with parasitic worms of the gut have suggested that certain individuals may be genetically predisposed to intense infection. In this study, the influence of parasitic helminth infection on levels of sHLA-I in plasma was investigated in 155 HLA typed individuals from St. Lucia, exposed to the gut parasite Trichuris trichiura. The results confirmed previous findings showing increased levels of sHLA-I in HLA-A9, and in this case HLA-A23 positive individuals. However, HLA-A9 positive individuals with high worm burden had significantly lower levels of sHLA-I in their plasma compared with HLA-A9 positive subjects with low worm burden. These results suggest that the intensity of T. trichiura infection influences the ability of HLA-A9 positive subjects to maintain high levels of sHLA-I.

Specificity of lymphocytotoxic autoantibodies (LCAbs) found in the serum of leprosy patients: class I MHC antigens

Lymphocytotoxic autoantibodies (LCAbs) of the IgM class have been identified in patients with borderline tuberculoid (BT) and borderline lepromatous (BL) leprosy with Type I reactions (I) as well as lepromatous leprosy (LL) patients with erythema nodosum leprosum reactions (ENL). The observation that lymphocytotoxic activity (LCA) was reduced in the presence of platelets led us to determine whether LCAbs had specificities for Class I Major Histocompatibility Complex (MHC) determinants. Absorption of LCA positive sera with platelets, classically used to deplete Class I specific lymphocytotoxic antibodies, reduced LCA towards autologous as well as allogeneic target cells. This was true for LCA positive sera from all patient classifications (group BT in the autologous system, p less than 0.01; in all other patient groups, p less than 0.001). Introducing B-2m to cytotoxicity assays only marginally reduced LCA when added at high concentrations (5 mg/ml). An anti-Class I MHC antiserum which blocked the lytic activity. The data indicate that LCAbs while absorbed by platelets, are not specific for the Class I MHC antigens. The autoantigen recognized by these autoantibodies therefore remains to be identified.

Sperm density measurement: should this be abandoned?

Sperm density measurement by means of the Makler chamber was performed on a single semen specimen from 2 groups: 104 proven fertile men and 53 infertile men; 11.5% of the fertile population had a sperm density less than 20 million/ml (median 84, mean 91.3, SD 60.5) and 33% of the infertile population had a sperm density greater than 20 million/ml (median 10, mean 26.9, SD 34.8). There was a statistically significant difference in median between the 2 groups, but when a discriminant analysis was applied, sperm density could predict fertile status with only 68% accuracy at optimum cut-off. Sperm density is valueless in distinguishing fertile from infertile men and is neither useful in diagnosis nor in monitoring the progress of treatment for male infertility. It should be abandoned as a quotable measurement of male fertility.

Serum lymphocytotoxic activity in leprosy

Sera from 167 patients across the spectrum of leprosy and 46 endemic controls were screened for lymphocytotoxic activity (LCA). The Terasaki microdroplet lymphocytotoxicity assay was performed at 37 degrees C and 15 degrees C to test sera for LCA against a panel of lymphocytes from 50 donors which represented most known HLA-ABC antigens. Raised complement-dependent LCA at 15 degrees C was seen in leprosy patients with histories of erythema nodosum leprosum (ENL) or reversal/Type I (I) reactions. Eighty-six per cent of lepromatous (LL) patients with a history of ENL (n = 21, P less than 0.001), 83% of borderline lepromatous (BL) and 88% of borderline tuberculoid patients (BT) with a history of Type I reactions (n = 12, P less than 0.01 and n = 24, P less than 0.001 respectively) had LCA compared to 39% of endemic controls (n = 46). LCA was attributed to IgM on the basis of reduced activity when serum was treated with both dithiothreitol or absorbed with antiserum for IgM. Removal of immune complexes and rheumatoid factor did not influence LCA. LCA-positive sera reacted similarly with allogeneic lymphocytes from either healthy donors or leprosy patients. Moreover LCA-positive sera reacted with autologous lymphocytes. Specificities for HLA-ABC antigens were not identified. The potential role of these autoantibodies, manifested in leprosy patients with hypersensitivity reactions remains speculative.