Generalized Loading Protocols for Experimentally Simulating Multidirectional Earthquake Actions on Building Columns in Regions of Low-to-Moderate Seismicity

This study aimed to quantitatively develop realistic quasi-static loading protocols for simulating bidirectional cyclic actions and axial load variation on building columns in a way that is representative of an actual response during earthquake ground excitation. A case-study building was subjected to a suite of 15 ground motions that were scaled to design basis earthquake (DBE) and maximum considered earthquake (MCE) levels of a typical region of low-to-moderate seismicity. The results showed that the displacement path of a building column under earthquake actions is generally in the form of elliptical loops of various orientations due to the phase difference in the sinusoidal displacements in the two orthogonal axes of the column. Accordingly, this work proposes a bidirectional lateral loading protocol that simplifies and generalizes the displacement path of the column in the form of elliptical loops of four different orientations. Similarly, the patterns of axial load variation in columns were also studied in detail, which led to the development of separate axial load variation protocols for external and internal columns of a building, which can be applied in tandem with the bidirectional lateral loading protocol. The paper concludes with a brief overview of the results of two reinforced concrete (RC) column specimens, which were experimentally tested using the proposed bidirectional loading protocol.</p

Investigation on the aerosol performance of dry powder inhalation hypromellose capsules with different lubricant levels

HPMC capsules are made by a dipping process and a surface lubricant for the mould pins is an essential processing aid for removing dried capsules shells. For the purpose of this study, the level was determined by quantifying methyloleate (MO) a component found in the lubricant but not in the hypromellose capsules. Here we investigated the influence of the lubricant, low (10.81 μg/capsule = 60 mg/kg MO), medium (15.97 μg/capsule = 90 mg/kg MO) and high (23.23 μg/capsule = 127 mg/kg MO) content on powder (binary mixture of salbutamol: lactose, 1:50 w/w) aerosolization properties was investigated. Results indicated significantly lower emitted dose from capsules with 60 mg/kg MO. Furthermore, the 90 and 127 mg/kg MO level of lubricant capsules produced almost double the Fine Particle Dose & Fine Particle Fraction compared with the low level of lubricant. The data indicates that lubricant level within capsules has an influence on deposition profiles and amount of drug remaining in capsule and inhaler device after actuation. It is suggested lubricant levels greater than 60 mg/kg MO per capsule are required to minimise powder retention within capsules and maximise deposition profiles. AFM (atomic force microscopy) data suggest that internal surface roughness may be related with this phenomena

Retrospective review of facial nerve schwannomas: the Universiti Kebangsaan Malaysia Medical Centre experience

Facial nerve schwannoma is a rare slow growing benign tumour which arises from the Schwann cell of the neurilemma. A retrospective review of 6 patients who had been diagnosed with facial nerve schwannoma between 1998 and 2008 was conducted. There was equal distribution of male and female patients. The mean age was 42 years (range 19 to 66 years). The tumour originated in the internal auditory canal (2 patients), intra-temporal (3 patients) and intraparotid (1 patient) segments of the facial nerve. All tumours were successfully removed and facial nerve continuity was pre-served in 2 cases. The presenting symptoms of facial nerve schwannoma are non specific and dependent on the site of tumour origin. It is a great mimicker of other lesions that can present at the same location. The surgeon should have a high index of suspicion when patients present with progressive facial nerve palsy. Patients should always be counselled regarding risk of facial paralysis because the diagnosis of facial nerve schwannoma is often confirmed intra-operatively

Cochlear implantation in children with labyrinthitis ossificans

Evidence of ossification was previously considered a relative contraindication to cochlear implantation. It was considered difficult or impossible to achieve safe electrode insertion because of bony obstruction. Either the electrodes or the inner ear structures could be damaged. Moreover, obstructed scala tympani could limit the number of electrodes that can be inserted. The efficacy of the electrical stimulation was also questioned, as a higher current would be needed on an ossified cochlea. Finally, the neural survival in ossified cochlea is unknown. This may complicate the surgical procedure and affect the long-term outcome. However, depending on the experience of the surgeon, cochlear implantation has been attempted even in grossly ossified cochlea. Here we illustrate that cochlear implantation is safe in labyrinthitis ossifican

Otogenic Brain Abscess: A retrospective study of 10 patients and review of the literature

Proper management of chronic otitis media may reduce the incidence of otogenic brain abscess. The aim of this study was to describe the clinical profile, treatment and surgical outcome of patients presenting with otogenic brain abscess. The medical record of patients in Universiti Kebangsaan Malaysia Medical Centre (UKMMC) with otogenic brain abscess were retrospectively analyzed from January 1997-January 2006. Within this period we had approximately 10,800 of follow up cases of chronic otitis media (COM) in our clinic. Ten patients (2 females, 8 males) with an average age of 42 (age range 11 to 69 years) were identified with otogenic brain abscess and included in this study. The mean follow-up period was 14 months. All patients had cholesteatoma. All patients had a history of chronic ear discharge, headache, otalgia and fever. Six of the 10 patients had cerebellar abscess and 4 had temporal lobe abscess. Cerebellar signs were present in 3 patients. All the patients were treated with broad-spectrum antibiotics. In 5 patients, mastoid exploration was the primary surgical treatment and the brain abscesses were treated conservatively. In the other 5 patients, craniotomy and drainage were performed followed by mastoid exploration when their neurological conditions had stabilized. All our patients had uneventful recovery. There were no permanent cerebellar signs during the follow up and no mortality reported in our series. In this series we demonstrated that early diagnosis and proper treatment of otogenic abscess leads to good neurological outcom

INTRAZEOLITE CARBONYL(ETA-5-CYCLOPENTADIENYL)DIHYDRIDOIRIDIUM(III) (CPIR(CO)H2-M56Y, WHERE M = H, LI, NA, K, RB, AND CS)

Vapor-phase impregnation and thermal equilibration of CpIr(CO)H2 in dehydrated M56Y (where M = H, Li, Na, K, Rb, and Cs) yields samples in which the guest displays two main anchoring modes. In Li56Y and Na56Y, a CpIrH2(CO)...M+ interaction is favored (type I), whereas in K56Y, Rb56Y, and Cs56Y the preferred-binding geometry involves CpIr(CO)H2...M+ (type II). The topology, spacial requirements, and ionic potential of the site II M+ cations appear to be mutually responsible for "lock-and-key" anchoring effects of CpIr(CO)H2 in the supercage of zeolite Y. The thermal and photochemical reactivities of CpIr(CO)H2-M56Y toward D2, HBr, CO, C6H6, and alkanes are investigated and compared with the situation known in solution. With D2, one finds only H/D exchange of the hydride ligands to yield intrazeolite CpIr(CO)D2-M56Y without hydride or Cp ring hydrogen scrambling, while exposure to CO yields the known intrazeolite species CpIr(CO)2-M56Y. In the case of both Bronsted acid H56Y and proton-loaded (HBr)8-Na56Y zeolites, one discovers a proton-induced, reductive-elimination, dimerization reaction, which yields the novel intrazeolite dimer Cp2Ir2(CO)2-M56Y anchored to a supercage Bronsted acid site via one of its bridge carbonyl ligands. By contrast to the situation found in solution, CpIr(CO)H2-M56Y so far appears to be photochemically and thermally inactive toward C-H bond activation chemistry with arenes and alkanes

Ear infection and hearing loss amongst headphone users

The use of headphone has been thought to cause infection in the ear canal and contribute to hearing loss. In this study, we examined 136 Customer Service Representative from Celcom (Malaysia) Sdn. Bhd. who use headphone throughout their working hours. The purpose of this study was to determine the prevalence of ear canal infection and other related diseases of the ear, nose and throat. Their hearing thresholds were also determined using the Amplaid 309 Clinical Audiometer. We found no incidence of infection of the external ear canal amongst the subjects. There were 4 cases of chronic middle ear infection and 4 cases of impacted wax. Hearing impairment was found in 25 subjects (21.2%). However, there was no significant association between hearing loss and the exposure to sound from headphone usage because the high frequencies were not predominantly affected. There was also no association between hearing loss and duration of service