Is beverage intake related to overweight and obesity in school children?

BACKGROUND AND AIM: Recently, considerable attention has been given to beverage intake as a source of calories which may be linked to pediatric obesity. The purpose of our study was to evaluate the beverage intake in school children and adolescents aged 7 to 15 years old. METHODS: Six hundred and seven (607) out of 655 children participated in the study. One hundred percent fruit juice were classified those beverages that contain 100% fruit juice, without sweetener. Sweetened sugar beverages (SSBs) were included (fruit drinks sweetened fruit juice, fruit-flavored drink or drink that contained fruit juice in part, sweeten soft drinks, coffee, and tea). RESULTS: Around 84% of subjects consumed water while 81% of children who were included in the analysis consumed milk, 49.5% consumed 100% fruit juice, and 79.4 % SSBs. Whole milk was consumed by 40.9% of school children. Skim milk and 1% milk were consumed by 3.6% and 4.7% of the children, respectively. Children and adolescents consuming SSBs were 2.57 (95% CI: 1.06, 3.38) times more likely to become obese compared to normal peers. CONCLUSION: Sugar beverage drinks but not 100% fruit juices and milk are associated with obesity. Further studies investigating the relationship among beverage consumption, total energy intake, and development of overweight are needed.

Evaluation of thyroid gland function in children with obstructive apnea hypopnea syndrome.

Patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and thyroid function abnormalities, such as hypothyroidism and Hashimoto's thyroiditis, usually have closely resembling clinical features. Differentiation between these disorders is made more difficult because hypothyroid patients are also at risk for secondary sleep-disordered breathing. The aim of our study is to evaluate the prevalence of thyroid function abnormalities in children with OSAHS. Forty-four children (15 females: 29 males), 2.5-14.5 (7.43±2.98) years old were studied with overnight polysomnography. Biochemical screening of thyroid gland function was also carried out. Patients were judged to have OSAHS based mainly on the evaluation of Apnea Hypopnea index per hour of sleep (AHI). 15/44 (34.1%) children had mild OSAHS, 17/44 (38.6%) moderate and 12/44 (27.3%) severe OSAHS. Hypothyroidism was recorded only in 5/44 (11.4%) and Hashimoto's thyroiditis in 3/44 (6.8%) of OSAHS patients. Two patients with hypothyroidism showed mild and three severe OSAHS, while from the 3 children with Hashimoto's thyroiditis one presented mild, one moderate and one severe degree of OSAHS. Although the majority of studies in bibliography worldwide do not consider necessary the systemic evaluation of thyroid gland function in patients with breathing disorders during sleep, it seems that in children this type of screening is required for the differential diagnosis between primary sleep apnea and hypothyroid sleep-disordered breathing in order to differentiate these two conditions. Therefore, the laboratory investigation of thyroid gland function could be considered necessary.

Alterations of bone mineral metabolism of children with different cell lineage types of acute lymphoblastic leukaemia under chemotherapy.

BACKGROUND: Children with haematological malignancies such as acute lymphoblastic leukaemia (ALL) may have alteration of bone mineral metabolism therefore increased risk for osteopenia and osteoporosis. PATIENTS AND METHODS: The purpose of this study was to examine the alterations of bone mineral metabolism in two groups of children (n=42) according to immunophenotyping (B-cell type, T-cell type) both quantitative (bone mineral density z-scores) and qualitative (serum osteocalcin - OC and carboxyl-terminal telopeptide of human type I collagen - ICTP) during diagnosis (T=0), after the intensified chemotherapy period (T=0.5) and the consolidation period (T=1). RESULTS: According to our results 15 patients had osteopenia and 1 child developed osteoporosis at T=0.5 and 13 patients had osteopenia at T=1. Mean BMD z-score was significantly decreased in both groups during chemotherapy and especially statistically significant decline of T-cell type ALL group compared with B-cell type ALL patients. OC mean level remains in low levels for both groups reaching in plateau during chemotherapy and ICTP level was increased in T-cell type ALL group of patients compared with B-cell type in both periods of chemotherapy. CONCLUSIONS: It seems that not only the combination of chemotherapeutic agents but also the cell lineage of ALL are important parameters of altering bone mineral metabolism.

Correlation of fl/d3 polymorphism of growth hormone receptor with the first- and second-year response to recombinant human growth hormone therapy in pre-pubertal Greek children with idiopathic isolated growth hormone deficiency.

BACKGROUND: fl/d3 polymorphism in human GH receptor was correlated with the response to GH therapy in different groups of children with short stature. AIM: This is a 2-yr retrospective study which evaluates the influence of fl/d3 polymorphism to the 1st-and 2nd-year response to GH replacement therapy in Greek children with isolated GH deficiency (GHD). SUBJECTS AND METHODS: A total number of 195 pre-pubertal Greek children were studied (121 controls and 74 patients with GH peak <10 ng/ml). Patients with deficiency were treated with exogenous GH at a mean dose of 28.8 µg/kg.d. Multiplex PCR was used to genotype all children for fl/d3 polymorphism, followed by statistical analysis. The main parameters which were used to assess the association of genotype with the response to GH replacement were height SD score (SDS), height gain SDS, and growth velocity (GV) expressed as cm/yr and SDS. RESULTS: Our results revealed that the frequency of d3-homozygosity in the Greek population was 8.26%. No association was detected between the presence or abcense of GHD and genotype. Moreover, no connection between genotype and sex was observed. First-year height SDS, height gain SDS, and GV SDS were significantly higher in d3-carriers (p<0.05). However, this difference did not appear in the 2nd year of treatment. CONCLUSIONS: In our study, the d3-polymorphism seems to be associated with a higher efficacy to GH replacement, at least at the beginning of the treatment.

First body fat percentiles for 607 children from Thessaloniki-Northern Greece.

BACKGROUND AND AIM: The purpose of this study was to establish for the first time reference curves for body fat levels in a Greek pediatric population aged 7-15y. METHODS: Six hundred and seven (607) children randomly selected from 8 primary and secondary schools from Northern Greece. Percentage body fat was measured by bioelectrical impedance analysis and percentile curves were constructed using the LMS method. All children were measured twice in the morning and the mean number of the two measurements was considered as the percentage of body fat. RESULTS: The mean number of the percentage body fat for the age group (7-9) was 18.2 ± 5.1 and 18.4 ± 6.1 for boys and girls, respectively. In the second age group (10-12) the girls had higher mean fat levels than boys (22.6 ± 5.8 vs. 20.4 ± 6.2). This increase was continued also in the third age group (13-15) with the girls having higher mean body fat levels (24.2 ± 5.5 vs. 17 ± 5.9). The 85th and 95th percentiles represented the cut-off point for overweight and obesity and it was (26.3, 33.0 and 28.9%) and (34.0, 38.2 and 38.1) for boys for the three age groups (7-9, 10-12 and 13-15), respectively. On the other hand, the girls had higher 85th and 95th percentiles for the same age group (7-9, 10-12, 13-15y) and it was (34.5, 32.9 and 33.6%) and (39.0, 370 and 38.3%), respectively. CONCLUSION: Body fat level, which is the component of overweight that leads to pathology, is a better representative over body mass index. These first percentile curves will be at great assistance helping the medical community to identify obesity in these children at early stages and to prevent development at pathological diseases early in their lives.

Effects of oral folate supplementation on serum total homocysteine and cholesterol levels in hyperhomocysteinemic children.

BACKGROUND: Hyperhomocysteinemia may be a risk factor for cardiovascular disease even among children. Increased levels of total serum homocysteine (tHcy) may initiate atherosclerosis by modulating increased cholesterol synthesis in the liver. Folate supplementation has been found to reduce homocysteine levels. However, no data have been reported about the relationship between folate supplementation and cholesterol levels in children. METHODS: Twenty of 26 hyperhomocysteinemic (>95th percentile for age) children underwent a therapeutic intervention of 5 mg of oral folate supplementation twice per week for 2 months. RESULTS: After the 2-month intervention with folate supplement, tHcy levels were statistically significantly decreased (P < .001), folate levels were significantly increased (P < .001), while total cholesterol levels were significantly improved from 183.8 (115-296 mg/dL) to 160.8 (109-265 mg/dL) (P < .05). CONCLUSIONS: Folate supplementation may reduce tHcy, serum folate, and total serum cholesterol levels in hyperhomocysteinemic children.

Oral supplementation of folic acid for two months reduces total serum homocysteine levels in hyperhomocysteinemic Greek children.

BACKGROUND & AIM: Hyperhomocysteimemia is a cardiovascular risk factor even among children. Supplementation of oral folic acid may reduce homocysteine levels to normal. However, data is limited at this point for healthy children and adolescents. METHODS: Five hundre and twenty four children participated in the study; Twenty six of them were found to be hyperho mocysteinemic(>95(th) percentile for age). Twenty of them received 5 mg of folic acid twice per week for two consecutive months while the other six received a diet rich in dietary folate. RESULTS: Serum homocysteine levels were statistically significantly decreased from 13.1 (10-24.2 micromol/L ) to 7.7 (4.9- 15.2 micromol/L), p<0.001. Serum folate levels were significantly rose from 4.3 (3-20 ng/mL) to 16.8 (7-20 ng/mL), p<0.001. On the contrary, no important changes were observed in the above parameters in children to whom a diet rich in folic acid was recommended. Homocysteine levels were found to be positively associated with age (r=0.314, p<0.001), BMI (r=0.192, p<0.001), WC (r = 0.215, p<0.001), simple sugars (r= 0.182, p<0.001 ) and negatively associated with folic acid (r = -0.331, p<0.001), vitamin B12 (r = -0.214, p<0.001) and dietary folic acid (r= -0.228, p=0.003). CONCLUSIONS: Oral folic acid 5 mg twice per week may efficiently reduce serum homocysteine levels and increase serum folic acid levels in healthy children with increased homocysteine levels (>95(th) percentile for age). Hyperhomocysteinemia in childhood may be a predictive factor of cardiovascular disease. In addition, these results may offer more help to health practioners in order to establish more prospective studies to elucidate the relationship between homocysteine, folic acid and heart disease in children.

Homocysteine lowering with folic acid supplements in children: effects on blood pressure.

Hyperhomocysteinemia is emerging as an independent predictor of cardiovascular disease and hypertension among children. The aim of the study was to examine the effects of oral folic acid on homocysteine and blood pressure. Folic acid supplementation has been found to reduce homocysteine levels and in some cases blood pressure. Five hundred and twenty children participated in the study, and 26 of them were found to be hyperhomocysteinemic; 20 of these children randomly received 5 mg oral folic acid supplement while the other six children were the controls. Serum homocysteine (P < 0.001) levels as well as systolic (P < 0.001) and diastolic (P = 0.045) blood pressure were statistically significantly decreased in the intervention group compared with the controls, while folic acid levels were statistically significantly increased (P < 0.001). Total serum homocysteine levels were correlated with age, serum folate, body mass index, and blood pressure. It appears that folic acid may be a safe and effective supplement to reduce homocysteine and possibly blood pressure, which consequently may prevent cardiovascular disease in children in early life.

Sound-evoked deflections of outer hair cell stereocilia arise from tectorial membrane anisotropy.

The exceptional performance of mammalian hearing is due to the cochlea's amplification of sound-induced mechanical stimuli. During acoustic stimulation, the vertical motion of the outer hair cells relative to the tectorial membrane (TM) is converted into the lateral motion of their stereocilia. The actual mode of this conversion, which represents a fundamental step in hearing, remains enigmatic, as it is unclear why the stereocilia are deflected when pressed against the TM, rather than penetrating it. In this study we show that deflection of the stereocilia is a direct outcome of the anisotropic material properties of the TM. Using force spectroscopy, we find that the vertical stiffness of the TM is significantly larger than its lateral stiffness. As a result, the TM is more resistant to the vertical motion of stereocilia than to their lateral motion, and so they are deflected laterally when pushed against the TM. Our findings are confirmed by finite element simulations of the mechanical interaction between the TM and stereocilia, which show that the vertical outer hair cells motion is converted into lateral stereocilia motion when the experimentally determined stiffness values are incorporated into the model. Our results thus show that the material properties of the TM play a central and previously unknown role in mammalian hearing.

Central precocious puberty due to hypothalamic hamartoma in a 7-month-old infant girl.

Hypothalamic hamartomas (HH) are rare congenital lesions of the tuber cinereum presenting with the classic triad of gelastic epilepsy, central precocious puberty (CPP) and developmental delay. In light of the important and diverse consequences of precocious puberty for affected children and their families, a correct diagnosis without delay is imperative. We present here a rare case of a 7-month-old infant girl with CPP and HH who was successfully treated with depot gonadotropin-releasing hormone (GnRH) analogue is presented.

Prevalence of hypertension and association of dietary mineral intake with blood pressure in healthy schoolchildren from northern Greece aged 7-15 years.

BACKGROUND AND AIMS: Pediatric hypertension is urgently increasing in Greece. The purpose of this study is to record the prevalence of hypertension in schoolchildren and to relate dietary minerals to blood pressure (BP). METHODS AND RESULTS: 308 males and 298 females, aged 7-15 years, from 10 schools in Northern Greece participated in the study. BP and dietary minerals were measured in all children. Twenty-seven and 12.3% of boys and 21.2 and 15.1% of girls were diagnosed with prehypertension systolic BP and systolic hypertension, respectively. For diastolic BP, 19 and 13.3% of boys and 21.5 and 15.1% of girls were diagnosed with prehypertension diastolic BP and diastolic hypertension, respectively. Systolic BP was significantly positively associated with age (beta: 0.283, 95% CI: 1.440-2.484, p < 0.001), BMI (beta: 0.267, 95% CI: 0.830-1.489, p < 0.001) and potassium (beta: 0.139, 95% CI: 0.001-0.005, p < 0.001) and negatively related to Ca (beta: -0.160, 95% CI: -0.012 to 0.002, p = 0.007). Diastolic BP was positively related only to BMI (beta: 0.194, 95% CI: 0.380-0.968, p < 0.001). CONCLUSION: The current study tried to estimate the prevalence of hypertension among children in Northern Greece. Early prevention through nutrition education programs on BP that include diet and exercise modifications is urgently needed in order to avoid certain chronic risk factors in early life.

Association of blood pressure, obesity and serum homocysteine levels in healthy children.

AIM: Obesity, hypertension and total serum homocysteine levels are well-known risk factors for cardiovascular disease in adults. However, there is limited data on the relation of these risk factors in children. METHODS: Five hundred twenty-four healthy school children aged 6-15 years participated in the study. BMI were used to categorize our subjects in normal overweight and obese groups based on Internationally Obesity Task Force criteria. RESULTS: The prevalence of overweight and obesity was 21.1% and 8.4% for boys and 17.6% and 7.3% for girls, respectively. Diastolic blood pressure (DBP), systolic blood pressure (SBP) and waist circumference (WC) were significantly higher in overweight and obese group compared to normal ones, whereas for homocysteine levels no difference was observed. Based on the results derived from the multiple regression analysis, BMI was positively related to energy intake (beta=0.247, p<0.001) and WC (beta=0.014, p<0.001). Both SBP and DBP were positively related to age ([beta=0.251, p<0.001] and [beta=0.301, p<0.001, respectively]), and BMI ([beta=0.096, p<0.001] and [beta=0.022, p<0.001], respectively). CONCLUSION: The current study revealed an association of blood pressure and WC with overweight and obesity in children, and even though these children may not have increased homocysteine levels, they still have enough reasons to reduce weight in order to avoid cardiovascular disease in their life later on.

Congenital bilateral anorchia: hormonal, molecular and imaging study of a case.

The aetiology of congenital bilateral anorchia is unknown. For many years there was speculation of an association between genetic factors and anorchia. We performed different tests in an anorchid boy, 2.5 years old, presented to us with micropenis and absence of both testes, in order to determine any possible factors contributing to the anorchia. Physical examination and hormonal, imaging, chromosomal, and molecular analyses of this case were performed. The basal FSH and LH levels were increased, and their increase in response to gonadotrophin-releasing hormone test was prolonged, while testosterone levels failed to increase after hCG administration. Ultrasonography of the pelvis and magnetic resonance of the abdomen were performed and failed to show any testicular tissue. Lastly, surgical exploration confirmed the absence of testicular structure. Chromosomal analysis revealed a normal male karyotype and molecular analysis did not reveal mutations or polymorphisms in the open reading frame of the SRY gene. Diagnostically, the lack of testosterone response to hCG stimulation is the hormonal hallmark of bilateral congenital anorchia. In addition, according to our case and previous studies, there is lack of association between genetic factors necessary for correct testicular descent and anorchia.

Reference range of total serum homocysteine level and dietary indexes in healthy Greek schoolchildren aged 6-15 years.

Elevated total serum homocysteine (tHcy) may be a possible risk factor for CVD. A 5 micromol/l increase in tHcy is associated with an approximately 70 % increase in relative risk of CVD in adults. Data for children and adolescents are, however, limited. The purpose of the present study was to provide a reference range for tHcy and investigate any relationship between tHcy and nutritional indexes in a Greek paediatric population. tHcy, folate, vitamin B12 levels and dietary indexes were measured in 520 healthy schoolchildren (274 boys, 246 girls) aged 6-15 years. As in adults, the tHcy distribution skewed to the right, with a geometric mean for both genders of 7.4 (range 3.4-29 micromol/l). Concentrations were lower in young children and increased with age. No statistically significant difference in tHcy level was observed between gender. The 95th percentiles for the three age groups were as follows: 6-9 years, 9.98 micromol/l; 10-12 years, 10.62 micromol/l; 13-15 years, 14.4 micromol/l. Using Pearson's coefficient analysis, tHcy level was correlated with age, serum folate, BMI and systolic blood pressure. Dietary analysis showed that folate, vitamin B12 and fibre intake were inversely related with tHcy; conversely, sugar and fat were positively associated with tHcy. However, in multiple linear regression analysis, only age (odds ratio 0.246, P < 0.05) and folate (odds ratio -0.346, P < 0.05) were significantly and independently associated with tHcy. This study provides age-specific reference data regarding tHcy concentration in a Greek paediatric population. tHcy levels increased as a function of age. Serum folate levels were significantly and independently associated with tHcy levels.

Congenital bilateral anorchia: hormonal, molecular and imaging study of a case

The aetiology of congenital bilateral anorchia is unknown. For many years there was speculation of an association between genetic factors and anorchia. We performed different tests in an anorchid boy, 2.5 years old, presented to us with micropenis and absence of both testes, in order to determine any possible factors contributing to the anorchia. Physical examination and hormonal, imaging, chromosomal, and molecular analyses of this case were performed. The basal FSH and LH levels were increased, and their increase in response to gonadotrophin-releasing hormone test was prolonged, while testosterone levels failed to increase after hCG administration. Ultrasonography of the pelvis and magnetic resonance of the abdomen were performed and failed to show any testicular tissue. Lastly, surgical exploration confirmed the absence of testicular structure. Chromosomal analysis revealed a normal male karyotype and molecular analysis did not reveal mutations or polymorphisms in the open reading frame of the SRY gene. Diagnostically, the lack of testosterone response to hCG stimulation is the hormonal hallmark of bilateral congenital anorchia. In addition, according to our case and previous studies, there is lack of association between genetic factors necessary for correct testicular descent and anorchia.

Efficient assembly of an HIV-1/MLV Gag-chimeric virus in murine cells.

In human cells infected by HIV type 1 (HIV-1), the viral Gag protein directs the assembly of nascent viral particles at the plasma membrane. In murine cells, HIV-1 Gag fails to reach the plasma membrane and instead forms nonfunctional intracellular aggregates. The viral determinants of this species incompatibility are previously undefined. To address this problem, we replaced a region of HIV-1 Gag known to direct its localization, the matrix (MA) domain, with functionally homologous regions from Moloney murine leukemia virus (MLV), a murine retrovirus. An HIV-1 clone carrying such a chimeric Gag protein, designated murine HIV (MHIV), assembled more efficiently than nonchimeric HIV-1 and restored plasma membrane localization of Gag in murine cells. Increased efficiency of viral assembly in murine cells was observed from MHIV constructs carrying MLV MA in place of HIV-1 MA. Efficient processing of the HIV-1 capsid protein from the chimeric Gag polyprotein and subsequent infectivity of MHIV required the presence of MLV p12 in addition to MLV MA. These findings strongly suggest that the HIV-1 MA domain of HIV-1 Gag is responsible for the assembly defect in mouse cells. Although these MHIV do not recruit native HIV-1 Env efficiently, they are capable of single-round infection when produced by high-efficiency transfection of human 293 cells and provided with an HIV-1 Env lacking its cytoplasmic tail. With further adaptation, this chimeric MHIV approach may provide the basis for creating an infectious mouse model for HIV/AIDS.

Non-isomerizable artificial pigments: implications for the primary light-induced events in bacteriorhodopsin.

The primary events in the photosynthetic retinal protein bacteriorhodopsin (bR) are reviewed in light of photophysical and photochemical experiments with artificial bR in which the native retinal polyene is replaced by a variety of chromophores. Focus is on retinals in which the "critical" C13=C14 bond is locked with respect to isomerization by a rigid ring structure. Other systems include retinal oxime and non-isomerizable dyes noncovalently residing in the binding site. The early photophysical events are analyzed in view of recent pump-probe experiments with sub-picosecond time resolution comparing the behavior of bR pigments with those of model protonated Schiff bases in solution. An additional approach is based on the light-induced cleavage of the protonated Schiff base bond that links retinal to the protein by reacting with hydroxylamine. Also described are EPR experiments monitoring reduction and oxidation reactions of a spin label covalently attached to various protein sites. It is concluded that in bR the initial relaxation out of the Franck-Condon (FC) state does not involve substantial C13=C14 torsional motion and is considerably catalyzed by the protein matrix. Prior to the decay of the relaxed fluorescent state (FS or I state), the protein is activated via a mechanism that does not require double bond isomerization. Most plausibly, it is a result of charge delocalization in the excited state of the polyene (or other) chromophores. More generally, it is concluded that proteins and other macromolecules may undergo structural changes (that may affect their chemical reactivity) following optical excitation of an appropriately (covalently or non-covalently) bound chromophore. Possible relations between the light-induced changes due to charge delocalization, and those associated with C13=C14 isomerization (that are at the basis of the bR photocycle), are discussed. It is suggested that the two effects may couple at a certain stage of the photocycle, and it is the combination of the two that drives the cross-membrane proton pump mechanism.

Palmitoylation of the HIV-1 envelope glycoprotein is critical for viral infectivity.

Recent studies suggest that HIV-1 budding occurs selectively from detergent-insoluble membrane domains, referred to as lipid rafts. Palmitoylation is thought to be one of the factors responsible for targeting membrane proteins to lipid rafts. The cytoplasmic domain of the HIV-1 envelope glycoprotein (gp160) contains two palmitoylated cysteine residues. In this work, we studied the solubility of gp160 after detergent extraction. We show that wild-type gp160 is mostly insoluble after ice-cold Triton X-100 extraction, but that it becomes almost completely soluble at 37 degrees C. In contrast, we find that a mutant gp160, in which the two palmitoylated cysteine residues are replaced by serine, is Triton X-100 soluble even under ice-cold extraction. These findings are consistent with the properties of proteins that localize to lipid rafts and strongly suggest that gp160 is associated with lipid rafts. Further, removal of both palmitoylation sites results in the formation of virus with low levels of gp160 incorporation as well as a decrease in viral infectivity by 60-fold. Our results strongly support the suggestion that HIV-1 buds from lipid rafts and point to a role for rafts as a viral assembly hub.

Effective light-induced hydroxylamine reactions occur with C13 = C14 nonisomerizable bacteriorhodopsin pigments.

The light-driven proton pump bacteriorhodopsin (bR) undergoes a bleaching reaction with hydroxylamine in the dark, which is markedly catalyzed by light. The reaction involves cleavage of the (protonated) Schiff base bond, which links the retinyl chromophore to the protein. The catalytic light effect is currently attributed to the conformational changes associated with the photocycle of all-trans bR, which is responsible for its proton pump mechanism and is initiated by the all-trans --> 13-cis isomerization. This hypothesis is now being tested in a series of experiments, at various temperatures, using three artificial bR molecules in which the essential C13==C14 bond is locked by a rigid ring structure into an all-trans or 13-cis configuration. In all three cases we observe an enhancement of the reaction by light despite the fact that, because of locking of the C13==C14 bond, these molecules do not exhibit a photocycle, or any proton-pump activity. An analysis of the rate parameters excludes the possibility that the light-catalyzed reaction takes place during the approximately 20-ps excited state lifetimes of the locked pigments. It is concluded that the reaction is associated with a relatively long-lived (micros-ms) light-induced conformational change that is not reflected by changes in the optical spectrum of the retinyl chromophore. It is plausible that analogous changes (coupled to those of the photocycle) are also operative in the cases of native bR and visual pigments. These conclusions are discussed in view of the light-induced conformational changes recently detected in native and artificial bR with an atomic force sensor.