Fabrication of fast mid-infrared range photodetector based on hybrid graphene-PbSe nanorods.

Weak light absorption of graphene has limited the responsivity of graphene-based photodetectors. On the other hand, the slow response of PbSe as a mid-infrared range (MIR) detector makes this type of detector unsuitable as a commercial detector. Here, we report a fast MIR detector based on hybrid graphene-PbSe nanorods. For this purpose, a few-layer graphene piece was synthesized using a simple, scalable, and economical method on a cobalt layer, the synthesized graphene was transferred onto interdigitated copper electrodes, and then synthesized nanorods were spin coated on the transferred graphene. Strong and tunable light absorption in the quantum dot layer creates electric charges, which are transferred to the graphene, and due to the high charge mobility of graphene and long trapped-charge lifetimes in the quantum dot layer, they recirculate many times. The fabricated device has high speed and responsivity. The gain of fabricated detectors based on hybrid graphene quantum dots is 10.3 times more, their response time is 14.3 times faster, and their responsivity is 10 times more than conventional nanorod-based detectors. From the point of view of spectral selectivity, tuning the size of the nanorods helps optical detection from the IR to mid-IR.

Migraine and its relation with lifestyle in women.

UNLABELLED: Migraine is a very common primary headache disorder with no underlying identifiable pathological cause. It has a profound effect on the well-being and general functioning of its victims. Migraine is best understood as a chronic disorder with episodic manifestations, progressive in some individuals, having dramatic social and economic costs. Migraine causes stress in patients and their families, changes the roles and lifestyles and disturbs the social interactions between family members. Being more common in women, migraine is a significant women's health concern. The low rate of headaches with identifiable organic causes suggests that individual and environmental factors are determinants of migraine. Therefore, studying lifestyle and its relation with migraine is very important. This study examines the relation between migraine headaches and lifestyle in women refereed to university clinics in Iran. METHODS: This is a case-control study of 170 patients selected randomly using Poisson sampling. The study population included female patients suffering from headache referred to the neurology clinics and health centers in Iran (with neurologist-diagnosed migraine according to the criteria of the International Society of Headache). The study population for the control group included women without migraine headache whose life conditions were similar to the migraine group and who were living in the same area. Data were collected by interview and a questionnaire which was tested for reliability and validity using content validity and retest methodologies. RESULTS: Findings showed a significant relation between some dimensions of lifestyle, such as diet eating habits (P = 0.001), resting and sleeping habits (P = 0.012), and drug usage patterns (P = 0.001) with migraine headaches. But there were no significant relationships noted between smoking, exercise or stress levels with migraine headaches. DISCUSSION: Lifestyle habits, including rest and sleep, diet and drug usage, are important factors in migraine attacks. It is important to emphasize changing habits, such as improper use of analgesics, to decrease side effects in migraine victims. The health centers should consider promoting healthy habits and behaviors as a priority in their services.

Direct identification of non-polio enteroviruses in residual paralysis cases by analysis of VP1 sequences.

BACKGROUND: The 66 serotypes of human enteroviruses (EVs) are classified into four species A-D, based on phylogenetic relationships in multiple genome regions. Partial VP(1) amplification and sequence analysis are reliable methods for identifying non-polio enterovirus serotypes, especially in negative cell culture specimens from patients with residual paralysis. OBJECTIVES: In Iran during the years 2000-2002, there were 29 residual paralysis cases with negative cell (RD, HEp(2) and L(20)B) culture results. STUDY DESIGN: The genomic RNA was extracted from stool specimens from cases of residual paralysis and detected by amplification of the 5'-nontranslated region using RT-PCR with Pan-EV primers. Partial VP(1) amplification by semi-nested RT-PCR (snRT-PCR) and sequence analysis were done. RESULTS: Specimens from the 29 culture-negative cases contained echoviruses of six different serotypes. CONCLUSIONS: The global eradication of wild polioviruses is near and study of non-polio enteroviruses, which can cause poliomyelitis, is increasingly important to understand their pathogenesis. The VP(1) sequences, derived from the snRT-PCR products, allowed rapid molecular analysis of these non-polio strains.

Characterization of mutations in the VP(1) region of Sabin strain type 1 polioviruses isolated from vaccine-associated paralytic poliomyelitis cases in Iran.

BACKGROUND: The live-attenuated oral polio vaccine used to interrupt poliovirus transmission is genetically unstable. Reversion of some attenuating mutations, which normally occurs during vaccine strain replication in some recipients, and can rarely cause vaccine-associated paralytic poliomyelitis (VAPP). The poliovirus eradication program designed by the World Health Organization (WHO) includes immunization with OPV in addition to careful surveillance of all acute-flaccid paralysis (AFP) cases. OBJECTIVES: In Iran we last isolated imported wild poliovirus in 2000 and the immunization coverage was 100% in 2002. During 2001, there were three AFP cases with residual paralysis from which Sabin-like type 1 polioviruses were isolated in our national polio laboratory. STUDY DESIGN: The complete VP(1) region of the three isolates was sequenced and amino acid substitutions associated with these neurovirulent isolates were recorded. RESULTS: These isolates had either 4, 2 or 1 nucleotide substitution(s) in the VP(1) region, corresponding to amino acid change in the VP(1) of isolate 1 of either (H-[149]->Y), (T-[106]->A) or (I-[90]->L), respectively. CONCLUSIONS: Surveillance of the VAPP cases in countries where endemic transmission has recently ceased increases our understanding of the important neurovirulent mutations in vaccine-strain isolates and assists in planning the next step in the eradication program in these countries.