Design and implementation of humidity sensor based on carbon nitride modified with graphene quantum dots.

Relative humidity (RH) is one of the most important factors that deserve intensive study because of its impact on many aspects of life. In this work humidity sensor based on carbon nitride / graphene quantum dots (g-C3N4/GQDs) nanocomposites have been developed. The structure, morphology and composition properties of the g-C3N4/GQDs were investigated and analyzed by XRD, HR-TEM, FTIR, UV-Vis, Raman, XPS and BET surface area. The average particle size of GQDs was estimated from XRD to be 5 nm and confirmed using HRTEM. The HRTEM images prove that the GQDs are attached to the external surface of the g-C3N4. The measured BET surface area was found to be 216 m2/g, 313 m2/g, and 545 m2/g for GQDs, g-C3N4, and g-C3N4/GQDs respectively. The d-spacing and crystallite size were estimated from XRD and HRTEM and found in a good matching. The humidity sensing behavior of g-C3N4/GQDs was measured in a wide span of humidity from 7% up to 97% RH under different testing frequencies. The obtained results demonstrate good reversibility and fast response/recovery time. The implemented sensor exhibits a great application prospect in humidity alarm devices, automatic diaper alarms, and breath analysis, which have advantages such as strong anti-interference capability, low cost, and easy to use.

Flock dynamics of desert Barki sheep in relation to age structure.

Reproduction data of 8689 ewe records spread over 40 years (from 1960 to 2000) representing 2952 breeding Barki ewes were used in this study. The flock belonged to the Desert Research Center in Egypt. Flock dynamics of nine age groups (2-10 yrs) were assessed. Two parameters were used to evaluate flock dynamics, net reproduction rate (R(o)) (number of ewe- lambs reaching joining age and produced by each ewe during its lifetime in the flock) and intrinsic rate of increase (r(m)) (flock growth when no resource is limiting). Age of ewe had a highly significant (P < 0.01) effect on number of ewes lambing per ewe joined (E(PJ)), number of lambs born per ewe joined (L(BJ)), number of lambs weaned per ewe joined (L(WJ)) and number of ewe lambs reaching joining age per ewe joined (L(EJ.J)). All estimates tended to increase with dams age up to four years and decreased thereafter. The results of R(o) and r(m) showed that the studied flock must consist of 5 age groups to maintain its size and replace itself. It may be recommended to cull the breeding ewe at the age of 6 years to accelerate genetic improvement.

Cytogenetic profile of Down syndrome in Alexandria, Egypt.

During 1992-2001, 673 Down syndrome patients were referred to the Department of Human Genetics in Alexandria. Regular (free) trisomy 21 constituted 95.4% of cases; Robertsonian translocation 2.7%; and mosaicism 0.7%. In 8 cases, regular trisomy 21 was associated with structural or numerical chromosome anomalies. Translocation was parentally inherited for 33.3% of cases and maternal transmission was twice as common as paternal. Two translocated Down syndrome fetuses were diagnosed prenatally in a t(14;21) carrier mother. Mean maternal age was high in regular trisomy 21 (38.2 years) but not in translocation (25.3 years). There was an excess of males in all groups except the mosaic group where the male:female ratio was 0.67. Cytogenetic investigations assist in patient management and family counselling.

Cytogenetic profile of Down syndrome in Alexandria, Egypt

During 1992-2001, 673 Down syndrome patients were referred to the Department of Human Genetics in Alexandria. Regular [free] trisomy 21 constituted 95.4% of cases; Robertsonian translocation 2.7%; and mosaicism 0.7%. In 8 cases, regular trisomy 21 was associated with structural or numerical chromosome anomalies. Translocation was parentally inherited for 33.3% of cases and maternal transmission was twice as common as paternal. Two translocated Down syndrome fetuses were diagnosed prenatally in at [14;21] carrier mother. Mean maternal age was high in regular trisomy 21 [38.2 years] but not in translocation [25.3 years]. There was an excess of males in all groups except the mosaic group where the male:female ratio was 0.67. Cytogenetic investigations assist in patient management and family counselling

Consanguinity and advanced maternal age as risk factors for reproductive losses in Alexandria, Egypt.

BACKGROUND: Consanguinity has been a long-standing social habit among Egyptians. Estimates of consanguinity ratios in different parts of Egypt ranged from 29 to 50%. This study aimed at delineating the role of consanguinity and advanced maternal age on reproductive losses in Alexandria, Egypt. METHODS: A case-control study, on 730 couples with history of reproductive losses and 2,081 normal couples, was done during the period October, 1998 until August, 2000. RESULTS: Of the 730 couples with reproductive losses, consanguinity frequency was 68.8% with 56.2% first cousins. Prenatal loss and infant deaths were highly encountered among consanguineous marriages (p < 0.0001). In a multivariate logistic regression analysis, consanguinity between couples increased the relative risk of repeated abortion (OR: 3.95; 95% CI: 3.04-5.14), stillbirths (OR: 10.6; 95% CI: 6.7-17.0), neonatal death (OR: 17.2; 95% CI: 10.8-27.3), post-neonatal death (OR: 14.5; 95% CI: 10.6-19.9) and total reproductive losses (OR: 8.3; 95% CI: 6.9-10.1). A positive association was found between advanced maternal age and repeated abortion (OR: 3.19; 95% CI: 2.04-4.97) as well as total reproductive losses (OR: 2.37; 95% CI: 1.74-3.2). CONCLUSION: This study, the largest-reported case-control study on reproductive losses in Alexandria, strongly suggests that consanguinity may play a major role in the high rates of prenatal and infant mortality while advanced maternal age has a significant role in the causation of repeated abortion, and they must be taken into account for genetic counseling in Egypt. Because of the possibility of controlling, the study gives clear indications for prevention.

Major birth defects among infants with Down syndrome in Alexandria, Egypt (1995-2000): trends and risk factors.

We evaluated the hypothesis that the trisomy 21 genome interacts with environmental factors during early pregnancy to increase the risk for birth anomalies in Down syndrome infants in Alexandria, Egypt. A case-control study on 514 infants with confirmed Down syndrome was carried out from 1 July 1995 to 30 June 2000. Genetic, biological, environmental and reproductive factors were analysed. Multiple logistic regression analysis showed the following factors to be independently associated with increased risk of congenital heart diseases among Down syndrome patients: parental consanguinity, maternal parents' consanguinity, mother's antibiotics use in pregnancy, oral contraceptive use and diabetes in the mother. Fever in the mother during pregnancy was associated with increased risk of gastrointestinal anomalies.

Major birth defects among infants with Down syndrome in Alexandria, Egypt [1995-2000]: trends and risk factors

We evaluated the hypothesis that the trisomy 21 genome interacts with environmental factors during early pregnancy to increase the risk for birth anomalies in Down syndrome infants in Alexandria, Egypt. A case-control study on 514 infants with confirmed Down syndrome was carried out from 1 July 1995 to 30 June 2000. Genetic, biological, environmental and reproductive factors were analysed. Multiple logistic regression analysis showed the following factors to be independently associated with increased risk of congenital heart diseases among Down syndrome patients: parental consanguinity, maternal parents' consanguinity, mother's antibiotics use in pregnancy, oral contraceptive use and diabetes in the mother. Fever in the mother during pregnancy was associated with increased risk of gastrointestinal anomalies

Congenital heart disease among school children in Alexandria, Egypt: an overview on prevalence and relative frequencies.

A study was undertaken to determine the prevalence and relative frequencies of congenital heart diseases diagnosed by echocardiography among school children in Alexandria, Egypt. The study was conducted during a 1-year period (1 May 1995-1 May 1996) at the Students' Health Insurance Hospital, which is a referral center for all health insurance units, providing an echocardiography service. The prevalence of congenital heart diseases (CHD) among school children accounted for 1.01/1,000. There was a male predominance in cases of pulmonary stenosis and single ventricle, while in cases of patent ductus arteriosus, mitral valve prolapse, and partial atrioventricular canal there was a female predominance. The commonest cardiac defects were ventricular septal defects, pulmonary stenosis, and atrial septal defects. Pulmonary stenosis ranked the second commonest defect and is a peculiar finding in our Egyptian population. The mere presence of these cardiac defects in school children is an indicator of the poor quality of care provided to this growing childhood population.

Risk factors for congenital heart diseases in Alexandria, Egypt.

A matched case control study has been conducted in the children's hospitals in Alexandria, Egypt, during 2 years-period, aiming at investigating the risk factors for the occurrence of congenital heart diseases. Our results showed that the significant risk factors for developing any type of congenital heart disease and ventricular septal defects were: older paternal age at birth, positive consanguinity, positive family history, female sex hormones, irradiation, hazardous maternal occupation, diabetes mellitus and suburban or rural residence. However, some environmental/teratogenic factors were not implicated in the etiology of atrial septal defects or pulmonary stenosis. These findings strongly suggest that environmental factors vary according to the specific type of congenital heart disease. This study emphasizes on the need to instruct the public about the importance of pre-marital counseling and the deleterious effects of various teratogens in the environment.

Nucleolus organizer region heteromorphism in patients with Down syndrome and their parents.

The study aimed to evaluate the role of nucleolus organizer region (NOR) heteromorphism as an etiological factor for parental nondisjunction in Down syndrome by comparing 25 patients affected by Down syndrome, and their parents with a control group of 80 non-affected Egyptians. All parents had normal karyotypes. The average modal number per parent of Ag-positive NORs was significantly higher in parents than controls. A significant difference in the size of the double-NOR variants (dNORs) was found. The mean maternal and paternal ages were significantly lower, with a significant increase in spontaneous abortions, for dNOR(+) couples compared with dNOR(-) couples.

Nucleolus organizer region heteromorphism in patients with Down syndrome and their parents

The study aimed to evaluate the role of nucleolus organizer region [NOR] heteromorphism as an etiological factor for parental nondisjunction in Down syndrome by comparing 25 patients affected by Down syndrome, and their parents with a control group of 80 non-affected Egyptians. All parents had normal karyotypes. The average modal number per parent of Ag-positive NORs was significantly higher in parents than controls. A significant difference in the size of the double-NOR variants [dNORs] was found. The mean maternal and paternal ages were significantly lower, with a significant increase in spontaneous abortions, for dNOR[+] couples compared with dNOR[-] couples

Chromosome damage in passive smoker females.

Current epidemiological data associates passive smoking with health hazards which not only affects the passive smoker but also affects the offsprings of passive smoker females. To determine the effect of cigarette smoke on the chromosomes of passive smoker females who were still in the childbearing age, the micronucleus (MN) frequency in 20 passive smoker females (spouse smoker) who had been exposed to cigarette smoke for at least 5 years was compared to the MN frequency in 20 control subjects (females with non-smoking spouse) all in the age group 31-39 years. The MN frequency among passive smoker female group ranged from 16-27 MN/500 cytokinesis blocked (CB) binucleated cell, with a mean of 21.1 +/- 3.7, while the MN frequency among the control group ranged from 3-11 MN/500 CB binucleated cell, with a mean of 8 +/- 1.7. The difference is statistically significant (t = 14.2, p < 0.01). Applying the correlation coefficient test between age and MN frequency, a weak positive though non significant correlation was found between age and MN frequency in the passive smoker female group (R = 0.11, p = 0.630) while an intermediate positive but still non significant correlation was found between age and MN frequency in the control (R = 0.26, p = 0.27). There was a positive correlation between the duration of exposure to cigarette smoke and the MN frequency, but this was statistically non significant (R = 0.33, p = 0.125). The results emphasize that mothers especially in the childbearing age should not be exposed to cigarette smoke to avoid its deleterious effects on their health thus preventing any harmful effect the smoke can have on their offsprings.

Autosomal recessive disorders among patients attending the genetics clinic in Alexandria

A total of 660 patients referred to the genetics clinic, Medical Research Institute, Alexandria were assessed to determine the frequency of genetic disorders and the proportion of autosomal recessive disorders. It was found that 298 [45.2%] patients had genetic disorders, 100 [33.6%] of whom had an autosomal recessive disorder; these included 32 patients with metabolic defects, 18 with haemoglobinopathies and 50 with syndromes and single defects. The frequency of consanguinity among parents of patients with autosomal recessive disorders was high [60%, with 48% first cousins]. The average inbreeding coefficient was higher [0.03] than that reported for the Egyptian population in general [0.01]

Chromosomal aberrations in children with suspected genetic disorders

Karyotyping was done in 137 children suspected of having chromosomal abnormalities such as genetically uncertain syndromes, multiple congenital anomalies, short stature, dysmorphic features, unclassified mental retardation and Down syndrome. A total of 53 [38.7%] had an abnormal karyotype: trisomy 21 [36; 26.3%], trisomy 18 [3; 2.2%], trisomy 13 [1; 0.7%], partial autosomal aneuploidy [5; 3.6%], pericentric inversion of chromosome 9 [2; 1.5%], marker chromosome [2; 1.5%] and sex chromosome aberrations [4; 2.9%]. All of them showed phenotypic-cytogenetic heterogeneity. These findings suggest that cytogenetic analysis is useful in the investigation of children with genetic disorders of unknown origin to confirm clinical diagnosis and to allow for proper genetic counseling

Genetic markers in coronary heart disease.

Coronary heart disease (CHD) was found to aggregate in families. So the present study aimed at studying certain genetic markers (lipoproteins, ABO blood groups and dermatoglyphics), in a group of 60 patients with CHD and a control group to detect any significant association between such genetics markers in this disorder. This can throw light on its genetics. The study revealed significant and marked association of CHD with low alpha-lipoprotein, high pre-beta and beta-lipoproteins. No significant association wa detected with ABO phenotypes. Definite significant association was also detected between CHD and certain dermatoglyphics phenotypes including FTP, T-D count and palm patterns. These significant associations of CHD and these genetic markers "which are genetically determined" denoted strongly genetic etiology or at least genetic predisposition of CHD. Detection of such genetic markers may help in determination of risky individuals in population and families of CHD patients. This can help in prevention by proper genetic counseling.