Time-resolved laser-induced desorption spectroscopy (LIDS) for quantified in-situ hydrogen isotope retention measurement and removal from plasma facing materials.

A laboratory scale laser induced thermal desorption spectroscopy system is developed and tested on tungsten-deuterium and titanium-deuterium codeposits, and its feasibility as a hydrogenic inventory measurement diagnostic is demonstrated over a range of retention values from 5 × 1019 m-2 to 7 × 1023 m-2 for absorbed laser power densities as low as 8 MW m-2. Codeposit layer samples are grown by magnetron sputtering and immersed in a weak argon rf plasma. A 1 kW fiber laser (λ = 1100 nm) heats the samples up to a peak surface temperature ranging from 900 to 1500 K using pulse widths of 0.5 and 1 s. Spectral line emission from Balmer series Dα and Hα from thermally desorbed deuterium and hydrogen, as well as line emission from argon, are monitored as a function of time using an optical spectrometer with maximum temporal resolution of 1 ms. To correct for wall recycling and pumping speed, and to accurately measure the time evolution of the laser-induced thermal desorption, the raw Dα signal is deconvolved with the system response function, which is obtained by injecting a short burst of D2 to approximate an impulse. Calibration is done with a standard D2 leak, and laser induced desorption spectroscopy deuterium retention values are found to be in good agreement with companion measurements made using conventional temperature programmed desorption on samples from the same codeposit batch.

Genetic variation in caveolin-1 correlates with long-term pancreas transplant function.

Pancreas transplantation is a successful treatment for a selected group of people with type 1 diabetes. Continued insulin production can decrease over time and identifying predictors of long-term graft function is key to improving survival. The aim of this study was to screen subjects for variation in the Caveolin-1 gene (Cav1), previously shown to correlate with long-term kidney transplant function. We genotyped 435 pancreas transplant donors and 431 recipients who had undergone pancreas transplantation at the Oxford Transplant Centre, UK, for all known common variation in Cav1. Death-censored cumulative events were analyzed using Kaplan-Meier and Cox regression. Unlike kidney transplantation, the rs4730751 variant in our pancreas donors or transplant recipients did not correlate with long-term graft function (p = 0.331-0.905). Presence of rs3801995 TT genotype (p = 0.009) and rs9920 CC/CT genotype (p = 0.010) in our donors did however correlate with reduced long-term graft survival. Multivariate Cox regression (adjusted for donor and recipient transplant factors) confirmed the association of rs3801995 (p = 0.009, HR = 1.83;[95% CI = 1.16-2.89]) and rs9920 (p = 0.037, HR = 1.63; [95% CI = 1.03-2.73]) with long-term graft function. This is the first study to provide evidence that donor Cav1 genotype correlates with long-term pancreas graft function. Screening Cav1 in other datasets is required to confirm these pilot results.

Patient need at the heart of workforce planning: the use of supply and demand analysis in a large teaching hospital's acute medical unit.

Timely medical assessment is integral to the safety and quality of healthcare delivery in acute medicine. Medical staff are an expensive resource. This study aimed to develop a modelling system that facilitated efficient workforce planning according to patient need on the acute medical unit. A realistic 24-hour 'supply' of junior doctors was calculated by adjusting the theoretical numbers on the rota for leave allowances, natural breaks and other ward duties by a combination of direct observation of working practice and junior doctor interviews. 'Demand' was analysed using detailed admission data. Supply and demand were then integrated with data from a survey of the time spent on the process of clerking and assessment of medical admissions. A robust modelling system that predicted the number of unclerked patients was developed. The utility of the model was assessed by demonstrating the impact of a regulation-compliant redesign of the rota using existing staff and by predicting the most efficient use of an additional shift. This simple modelling system has the potential to enhance quality of care and efficiency by linking workforce planning to patient need.

Pain-related fear: a critical review of the related measures.

OBJECTIVES: In regards to pain-related fear, this study aimed to: (1) identify existing measures and review their measurement properties, and (2) identify the optimum measure for specific constructs of fear-avoidance, pain-related fear, fear of movement, and kinesiophobia. DESIGN: Systematic literature search for instruments designed to measure fear of pain in patients with persistent musculoskeletal pain. Psychometric properties were evaluated by adjusted Wind criteria. RESULTS: Five questionnaires (Fear-Avoidance Beliefs Questionnaire (FABQ), Fear-Avoidance of Pain Scale (FAPS), Fear of Pain Questionnaire (FPQ), Pain and Anxiety Symptoms Scale (PASS), and the Tampa Scale for Kinesiophobia (TSK)) were included in the review. The main findings were that for most questionnaires, there was no underlying conceptual model to support the questionnaire's construct. Psychometric properties were evaluated by diverse methods, which complicated comparisons of different versions of the same questionnaires. Construct validity and responsiveness was generally not supported and/or untested. CONCLUSION: The weak construct validity implies that no measure can currently identify who is fearful. The lack of evidence for responsiveness restricts the current use of the instruments to identify clinically relevant change from treatment. Finally, more theoretically driven research is needed to support the construct and thus the measurement of pain-related fear.

CD226 Gly307Ser association with multiple autoimmune diseases.

Genome-wide association studies provide insight into multigenic diseases through the identification of susceptibility genes and etiological pathways. In addition, the identification of shared variants among autoimmune disorders provides insight into common disease pathways. We previously reported an association of a nonsynonymous single nucleotide polymorphism (SNP) rs763361/Gly307Ser in the immune response gene CD226 on chromosome 18q22 with type 1 diabetes (T1D) susceptibility. Here, we report efforts toward identifying the causal variant by exonic resequencing and tag SNP mapping of the 18q22 region in both T1D and multiple sclerosis (MS). In addition to the analysis of newly available samples in T1D (2088 cases and 3289 controls) and autoimmune thyroid disease (AITD) (821 cases and 1920 controls), resulting in strong support for the Ser(307) association with T1D (P=3.46 x 10(-9)) and continued potential evidence for AITD (P=0.0345), we provide evidence for association of Gly307Ser with MS (P=4.20 x 10(-4)) and rheumatoid arthritis (RA) (P=0.017). The Ser(307) allele of rs763361 in exon 7 of CD226 predisposes to T1D, MS, and possibly AITD and RA, and based on the tag SNP analysis, could be the causal variant.

Analysis of HLA class II genes in Hashimoto's thyroiditis reveals differences compared to Graves' disease.

Graves' disease (GD) and Hashimoto's thyroiditis (HT) represent the commonest forms of autoimmune thyroid disease (AITD) each presenting with distinct clinical features. Progress has been made in determining association of HLA class II DRB1, DQB1 and DQA1 loci with GD demonstrating a predisposing effect for DR3 (DRB1(*)03-DQB1(*)02-DQA1(*)05) and a protective effect for DR7 (DRB1(*)07-DQB1(*)02-DQA1(*)02). Small data sets have hindered progress in determining HLA class II associations with HT. The aim of this study was to investigate DRB1-DQB1-DQA1 in the largest UK Caucasian HT case control cohort to date comprising 640 HT patients and 621 controls. A strong association between HT and DR4 (DRB1(*)04-DQB1(*)03-DQA1(*)03) was detected (P=6.79 x 10(-7), OR=1.98 (95% CI=1.51-2.59)); however, only borderline association of DR3 was found (P=0.050). Protective effects were also detected for DR13 (DRB1(*)13-DQB1(*)06-DQA1(*)01) (P=0.001, OR=0.61 (95% CI=0.45-0.83)) and DR7 (P=0.013, OR=0.70 (95% CI=0.53-0.93)). Analysis of our unique cohort of subjects with well characterized AITD has demonstrated clear differences in association within the HLA class II region between HT and GD. Although HT and GD share a number of common genetic markers this study supports the suggestion that differences in HLA class II genotype may, in part, contribute to the different immunopathological processes and clinical presentation of these related diseases.

Preliminary evidence for interaction of PTPN12 polymorphism with TSHR genotype and association with Graves' ophthalmopathy.

OBJECTIVE: Protein tyrosine phosphatases (PTPs), such as PTPN22, are important regulators of signal transduction from the T cell receptor and have been associated with autoimmunity. PTPN12 interacts with the same T cell activation accessory molecules, Grb2 and Csk kinase, as the Graves' disease (GD) associated PTPN22 encoded lymphoid tyrosine phosphatase (LYP) molecule and also plays a key role in T cell receptor signalling, leading to the hypothesis that it too may be involved in GD susceptibility. DESIGN: PTPN12 was tested for association in a large well-characterized UK Caucasian case control cohort using seven tagging single nucleotide polymorphisms (SNPs). Patients A total of 1058 GD patients and 864 controls. Measurements Tests for association with the disease. RESULTS: Despite adequate statistical power to detect an effect if present, none of the seven tag SNPs were associated with GD (P = 0.925-0.089). Three SNPs (rs1468682, rs4729535 and rs17467232), however, demonstrated association with the presence of ophthalmopathy NOSPECS classes 2-4 (P = 0.039-0.004). Four SNPs (rs1468682, rs4729535, rs17155601 and rs17467232) revealed evidence of interaction with the previously associated thyrotropin hormone receptor (TSHR) rs2268458 SNP (P = 0.035-0.002). CONCLUSIONS: No association was detected between individual PTPN12 tag SNPs and GD but preliminary evidence suggests PTPN12 confers an increased risk of mild/moderate ophthalmopathy (NOSPECS classes 2-4) and that PTPN12 interacts with the TSHR. Replication of these preliminary results is now required in larger independent datasets to validate these findings.

Tag SNP screening of the PDCD1 gene for association with Graves' disease.

OBJECTIVE: The Programmed Cell Death 1 gene (PDCD1) on chromosome 2q37.3 encodes PD-1 which is involved in providing a negative signal to activated T cells. Large case-control studies have shown association of PDCD1 with several autoimmune diseases although, to date, no such studies have been performed for Graves' disease (GD). The objective of our study was to investigate eight tag SNPs representing the majority of common variation in PDCD1 within a well-characterized large UK Caucasian GD dataset. DESIGN: A case control association study of eight polymorphisms. PATIENTS: 2671 Graves' disease patients and 864 controls. MEASUREMENTS: Tests for association with disease. RESULTS: No association with disease was seen for any of the +4163, +5049, +5318, +5640, +5678 and +7078 SNPs genotyped in this study. Association was detected between the +2375 SNP (P = 0.021, OR = 1.14 [95% CI = 1.01-1.29]) and GD and a small protective effect was seen with the +6799 SNP genotypes (P = 0.028, OR = 0.77 [95% CI = 0.58-1.03]). CONCLUSIONS: This study has, for the first time, shown that small effects within PDCD1 may contribute towards the development of GD, supporting the hypothesis that much of the currently unknown genetic contribution to GD could be due to several small genetic effects with ORs 1.2. Replication of this result is now needed to confirm our findings and justify more detailed fine mapping of a primary aetiological variant in this gene region.

The HLA Region and Autoimmune Disease: Associations and Mechanisms of Action.

The HLA region encodes several molecules that play key roles in the immune system. Strong association between the HLA region and autoimmune disease (AID) has been established for over fifty years. Association of components of the HLA class II encoded HLA-DRB1-DQA1-DQB1 haplotype has been detected with several AIDs, including rheumatoid arthritis, type 1 diabetes and Graves' disease. Molecules encoded by this region play a key role in exogenous antigen presentation to CD4+ Th cells, indicating the importance of this pathway in AID initiation and progression. Although other components of the HLA class I and III regions have also been investigated for association with AID, apart from the association of HLA-B*27 with ankylosing spondylitis, it has been difficult to determine additional susceptibility loci independent of the strong linkage disequilibrium (LD) with the HLA class II genes. Recent advances in the statistical analysis of LD and the recruitment of large AID datasets have allowed investigation of the HLA class I and III regions to be re-visited. Association of the HLA class I region, independent of known HLA class II effects, has now been detected for several AIDs, including strong association of HLA-B with type 1 diabetes and HLA-C with multiple sclerosis and Graves' disease. These results provide further evidence of a possible role for bacterial or viral infection and CD8+ T cells in AID onset. The advances being made in determining the primary associations within the HLA region and AIDs will not only increase our understanding of the mechanisms behind disease pathogenesis but may also aid in the development of novel therapeutic targets in the future.

Association of the BTNL2 rs2076530 single nucleotide polymorphism with Graves' disease appears to be secondary to DRB1 exon 2 position beta74.

OBJECTIVE: The HLA region encodes numerous immune response genes, with the DR/DQ molecules consistently associated with autoimmune disease (AID). Recent studies in sarcoidosis have identified association of a single nucleotide polymorphism (SNP) rs2076530 within BTNL2, a potential T-cell inhibitor, independent of the known DRB1 association. The aim of this study was to investigate the association rs2076530 with disease in a large UK Caucasian Graves' disease (GD) dataset. DESIGN: A case control association study of the rs2076530 polymorphism. PATIENTS: Eight hundred sixty-four Graves' disease patients and 864 controls. MEASUREMENTS: Tests for association with disease. RESULTS: We detected association of rs2076530 within a large GD dataset [OR = 1.32 (95% CI = 1.14-1.52)], however, linkage disequilibrium (LD) analysis revealed association of rs2076530 to be secondary to the previously established DRB1 exon 2 encoded position beta74 effect although a rare haplotype effect, including both loci, cannot be excluded. CONCLUSIONS: BTNL2 may be a sarcoidosis-specific susceptibility loci, although only extensive examination of the whole HLA region in different inflammatory/AIDs will enable DR/DQ independent HLA effects to be determined.

Use of Tag single nucleotide polymorphisms (SNPs) to screen PTPN21: no association with Graves' disease.

OBJECTIVE: The protein-tyrosine-phosphate nonreceptor 22 gene (PTPN22) has recently been identified as a susceptibility locus for a number of autoimmune diseases including Graves' disease (GD). PTPN21 is another member of the PTPN family and its gene PTPN21 maps to the first reported region of genetic linkage to GD, GD-1, on chromosome 14q31. The aim of this study was to determine whether PTPN21 is acting as a GD susceptibility locus in UK Caucasian subjects. DESIGN: A case control association study of seven Tag single nucleotide polymorphisms (SNPs) (rs1469602, rs8007288, rs1998670, rs11622270, rs2274736, rs2295136 and rs366476) selected to predict 51 un-genotyped polymorphisms present within PTPN21. PATIENTS: Unrelated Caucasian patients of UK origin with GD and ethnically and gender matched control subjects with no family history of autoimmune disease were recruited. In total, DNA was obtained from 768 GD patients and 768 control subjects. RESULTS: No association of any of the seven Tag SNPs was detected with GD. Preliminary evidence of association of rs2274736 was found with younger age of GD onset (0-30 years) (OR = 1. 48 [95% CI = 1.11-1.97]). No other correlations with clinical phenotype or previously established susceptibility loci were detected. CONCLUSIONS: Using a Tag SNP approach we screened PTPN21 as a susceptibility locus for GD and found no evidence for association with disease. Preliminary evidence for association of rs2274736 with younger age of GD onset requires replication in similar sized data sets to exclude a false positive result. Methods such as the Tag SNP approach significantly reduce the amount of genotyping required when screening candidate loci, including those within regions of chromosomal linkage.

Contribution of single nucleotide polymorphisms within FCRL3 and MAP3K7IP2 to the pathogenesis of Graves' disease.

CONTEXT: Recently six DNA variants, two of which (M55V and 001Msp) are present in nuclear factor-kappaB inhibitors SUMO-4 and MAP3K7IP2 and four of which (fcrl3_3, fcrl3_4, fcrl3_5, and fcrl3_6) modulate nuclear factor-kappaB binding and production of the B cell surface molecule FCRL3, have been reported to be associated with a number of autoimmune diseases. OBJECTIVE: The aim of this study was to investigate the association of these polymorphisms with disease in a large UK Caucasian Graves' disease (GD) data set. DESIGN: The study was a case-control association study of six polymorphisms. SETTING: The study was conducted at a UK academic department of medicine. PATIENTS OR PARTICIPANTS: Study population included 1056 GD patients and 864 controls. INTERVENTIONS: There were no interventions. MAIN OUTCOME MEASURES: Tests for association with disease were measured. RESULTS: No association with disease was found for the M55V single-nucleotide polymorphism (SNP). Association was, however, found between GD and the 001Msp SNP [odds ratio (OR) 1.19 (95% confidence interval [CI]) 1.03-1.37], fcrl3_3 SNP [OR 1.17 (95% CI 1.02-1.34)], fcrl3_5 SNP [OR 1.18 (95% CI 1.04-1.35)], and fcrl3_6 SNP [OR 1.20 (95% CI 1.05-1.36)]. The 001Msp SNP was found to be associated with the presence of TSH receptor autoantibodies [OR 1.75 (95% CI 1.09-2.79)]. CONCLUSION: Functional evidence suggests that the 001Msp, fcrl3_3, fcrl3_5, and fcrl3_6 SNPs could cause changes in B cell signaling and activation pathways that could account for their association with GD. Further replication in independent data sets and fine mapping of the surrounding gene regions are needed to confirm the magnitude of the effect and location of the etiological variant(s) present within these gene regions.

A systematic approach to the assessment of known TNF-alpha polymorphisms in Graves' disease.

Single-nucleotide polymorphisms (SNPs) within the tumour necrosis factor alpha (TNF-alpha) gene on chromosome 6p21.3 have been associated with many autoimmune diseases; however, results have been conflicting and accurate allele frequencies have never been established in a UK Caucasian population. The aim of this study was to assess the frequency of 22 known TNF-alpha SNPs in a UK Caucasian control population and investigate association of all polymorphisms with >5% minor allele frequency in a large case-control data set of patients with Graves' disease (GD). Eight of the 22 SNPs had minor allele frequencies >5% and were investigated further. The other 14 SNPs were present in the UK population at frequencies ranging from 0 to 4.7%. A significant increase of the A allele of the -238 SNP was seen in GD patients when compared with control subjects (9.6 vs 6.8%, respectively; P=0.003) and mirrored in the genotype distribution (P=0.009). Furthermore, association of the -238 SNP appears not to be due to linkage disequilibrium of the known HLA-DRB1(*)03 associations with GD. This study has established accurate allele frequencies of TNF-alpha SNPs in a UK population and provides preliminary evidence for association of the TNF-alpha gene with GD.

Unravelling the genetic complexity of autoimmune thyroid disease: HLA, CTLA-4 and beyond.

The autoimmune thyroid diseases (AITDs) including Graves' disease (GD) and autoimmune hypothyroidism (AIH) are the commonest of the autoimmune conditions affecting 2-5% of the western population. Twin studies have clearly demonstrated that AITDs are caused by a combination of both environmental and genetic factors. Association of the HLA class II region with AITD has been documented for over 20 years now, but the primary aetiological variant in this region remains unknown. More recently the CTLA-4 gene region has been identified as the second locus conferring susceptibility to AITD. In contrast to HLA, a polymorphism of the CTLA-4 gene, which encodes an important negative regulator of the immune system, has been identified as a candidate for a primary determinant for AITD. A large number of candidate gene and genome wide linkage studies have been involved in the search for the elusive 'third' locus. The thyroglobulin (Tg) gene in humans maps to chromosome 8q, which has been linked in family studies to AITD. A number of association studies in humans and the mouse model for AITD are beginning to implicate the Tg gene although convincing evidence for a primary causative role is still needed. The establishment of large DNA disease resources along with more detailed genetic maps and the development of faster, more effective, high throughput genotyping and sequencing methods, provides some sense of optimism that novel loci will be identified in the near future and the complex aetiology of AITD will be further unraveled.

Genetic insights into disease mechanisms of autoimmunity.

Educating the immune system to distinguish between self and non-self is critical to ensure that an immune response is mounted against foreign antigens and not against self. A breakdown in these mechanisms can lead to the onset of autoimmune disease. Clinical and molecular data suggest that shared immunogenetic mechanisms lead to the autoimmune process. The most studied genes and molecules are the human leukocyte antigen (HLA) region and the cytotoxic T-lymphocyte-associated 4 molecule (CTLA-4). Recently progress has been achieved in narrowing down the primary variants within both gene regions, but further work is needed to determine the function and extent of the aetiological variant(s) present. Recent exciting results also suggest a role for the newly discovered lymphoid-specific phosphatase (LYP) protein. As well as these general mechanisms, disease-specific mechanisms are beginning to be elucidated, for example the role of autoimmune regulatory element 1 (AIRE1) in autoimmune polyendocrinopathy-candidiasis ectodermal dystrophy (APECED). Taken together, these data suggest that both general and disease-specific mechanisms lead to the clinical outcome of autoimmune disease and that increased understanding of these mechanisms will improve our knowledge of how autoimmune disease occurs, eventually leading to the development of novel therapeutic agents.

Self-reports and clinician-measured physical function among patients with low back pain: a comparison.

OBJECTIVE: To determine the relationships among self-reported activity limitation and clinician-measured functional performance tests. DESIGN: Case series survey. SETTING: A referral-based orthopedic spine clinic in Houston, TX. PATIENTS: Eighty-three patients (48 women, 35 men) with low back pain (LBP). INTERVENTIONS: The Roland-Morris Disability Questionnaire (RMDQ) and a physical performance test (PPT) battery. MAIN OUTCOME MEASURES: Self-reported activity limitation (eg, walking, bending, getting out of chair, putting on sock, doing heavy jobs) was assessed by the RMDQ. Clinician-measured functional performance was assessed with the PPT, a battery comprised 6 tests: lumbar flexion range of motion, a 50-foot walk at fastest speed, a 5-minute walk, 5 repetitions of sit-to-stand, 10 repetitions of trunk flexion, and loaded reach task (patients reached forward while holding a weight weighing 5% of their body weight). RESULTS: Pearson's product-moment correlations between total RMDQ score and each of the performance tests ranged from.29 to.41. Point biserial correlations between individual RMDQ items and their corresponding performance tests were slightly lower, ranging from.20 to.33. CONCLUSION: There were moderate correlations between self-reported activity limitation and corresponding clinician-measured performance tests. The unique perspective each method provides appears to be useful for a comprehensive understanding of physical function in patients with LBP.

Molecular organization of tight and adherens junctions in the human placental vascular tree.

Tight and adherens junctions are major determinants of endothelial integrity. Molecules present therein have been implicated in vascular permeability, stability of junctions, angiogenesis and intracellular signalling. Using immunofluorescence and confocal scanning microscopy, the adherens junctions (AJs) in human placental vessels were found to contain the entire cadherin-catenin complex predicted from in vitro studies. Vascular endothelial cadherin (VE-cadherin) clusters were co-localized with beta-catenin, an important signal transduction ligand, and with alpha-catenin, which is thought to link the complex to the peri-junctional actin. Antibodies to plakoglobin, a molecule shown to be a component of stable adherens junctions, revealed immunoreactivity in clefts of stromal villous vessels, but weak or negative immunoreactivity in intermediate and terminal villi. Tight junctional molecules demonstrated a differential surface expression. Within the same villous tree, arteries, veins and arterioles contained occludin but the exchange vessels in terminal villi were immunonegative. ZO-1, however, was present throughout. Ultrastructurally, there were no differences in frequency, position or dimension of tight junctions in these vessels. They showed a consistent 4 nm separation between outer membrane leaflets regardless of their location in the vascular tree. Occludin is not necessary for formation of tight junctions in the placenta; it may have an accessory role providing stability or added adhesiveness to tight junctions of large vessels. Its absence in terminal villous microvessels, along with the weak plakoglobin immunoreactivity in AJs, suggest that the junctions here are less stable. This may allow the increased plasticity necessary in terminal villi for continual growth, proliferation and solute exchange.

Physical performance: differences in men and women with and without low back pain.

OBJECTIVE: To determine the extent to which there may be major differences in scores on a battery of physical performance tasks among men with nonspecific, mechanical low back pain (LBP), women with LBP, healthy men, and healthy women. DESIGN: Case series survey. SETTING: A referral-based orthopedic clinic. PATIENTS: Thirty-three men and 46 women with LBP. Control Subjects: Twenty-one men and 25 women healthy controls. INTERVENTION: Completion of six clinician-assessed physical performance tasks and self-report inventories. MAIN OUTCOME MEASURE: Performance scores on distance walked in 5 minutes, 50-foot walk at fastest speed, repeated sit-to-stand, repeated trunk flexion, loaded forward reach, and the Sorensen fatigue tasks. RESULTS: Discriminant function analysis revealed that the four groups of subjects performed the physical tasks significantly different in two major ways: (1) healthy control subjects outperformed LBP patients, irrespective of gender, on tasks involving trunk control, coordination, and stability while withstanding heavy or quickly changing loads on the spine; (2) men outperformed women, irrespective of patient or nonpatient status, on tasks involving anthropometric features of limb length. The findings provide guidance on reasonable performance expectations for men and women patients with LBP. Future studies of treatment effectiveness also will be able to assess physical performance change in terms of the intersection between standards set by the men and women healthy control subjects and those of men and women patients. However, whether a return to nonpatient status is an appropriate treatment goal is left to future research.