The Ultimate Bond

Being introduced in India in 1956 as an easy –to-use white glue for carpenters in replacement of Saresh (fat-based adhesives), the ULTIBOND company started its journey and never looked back. As The ULTIBOND Company was well known to recognize the need of their product and convert it into a marvelous opportunity, the company started manufacturing AI glue products for students as well as for professional and educational institutes. In order to shift end-users from natural glues and other synthetic adhesives available at the time, AI glue embarked on a bold marketing game plan. Instead of selling through stores, AI glue approached carpenters directly. This direct marketing initiative was one of the most successful strategies employed by the company and helped the brand gain a strong foothold in the white glue market. By 1965, the brand was big enough to develop its own manufacturing plant in Maharashtra. Primarily the company decided to enter into the retail market with a packaging of 33 grams collapsible tube in early 1970’s, later came up with many other unique packaging styles to cater the need and requirements of different segments of its customer base.

Mimicking a flow-limited human upper airway using a collapsible tube: relationships between flow patterns and pressures in a respiratory model

The upper airway (UA) in humans is commonly modeled as a Starling resistor. However, negative effort dependence (NED) observed in some patients with obstructive sleep apnea (OSA) contradicts predictions based on the Starling resistor model in which inspiratory flow is independent of inspiratory driving pressure when flow is limited. In a respiratory bench model consisting of a collapsible tube and an active lung model (ASL5000), inspiratory flow characteristics were investigated in relation to upstream, downstream, and extra-luminal pressures (denoted as Pus, Pds, and Pout, respectively) by varying inspiratory effort (muscle pressure) from −1 to −20 cmH2O in the active lung. Pus was provided by a constant airway pressure device and varied from 4 to 20 cmH2O, and Pout was set at 10 and 15 cmH2O. Upstream resistance at onset of flow limitation and critical transmural pressure (Ptm) corresponding to opening of the UA were found to be independent of Pus, Pds, and Pout. With fixed Ptm, when Pds fell below a specific value (Pds′), inspiratory peak flow became constant and independent of Pds. NED plateau flow patterns at mid-inspiration (V̇n) were produced within the current bench setting when Pds fell below Pds′. V̇n was proportional to Pds, and the slope (ΔV̇n/ΔPds) increased linearly with Ptm. Ptm and Pds were the two final independent determinants of inspiratory flow. Our bench model closely mimics a flow-limited human UA, and the findings have implications for OSA treatment and research, especially for bench-testing auto-titrating devices in a more physiological way. NEW & NOTEWORTHY A respiratory model consisting of a collapsible tube was used to mimic a flow-limited human upper airway. Flow-limited breathing patterns including negative effort dependence were produced. Transmural and downstream pressures acting on the tube are the two independent determinants of the resulting inspiratory flow during flow limitation. The findings have implications for obstructive sleep apnea treatment and research, especially for bench-testing auto-titrating devices in a more physiological way.

Feedback modulation of surrounding pressure determines the onset of negative effort dependence in a collapsible tube bench model of the pharyngeal airway

Negative effort dependence (NED), decreased airflow despite increased driving pressure, has been proposed as a specific obstructive sleep apnea (OSA) phenotypic characteristic. We examined conditions under which NED occurs in a collapsible tube, pharyngeal airway bench model with the chamber enclosed, focusing on relationships with surrounding pressure levels and longitudinal strain. Using a vacuum source, graded airflows (V̇; 0–5 l/s) were generated through a thin-walled latex tube enclosed within a rigid, cylindrical chamber, sealed with initial chamber pressures (Pci) of 0–5 cmH2O (separate runs), or opened to the atmosphere. Upstream minus downstream pressure (Pu − Pd), maximum airflow (V̇max), and chamber pressure (Pc) were measured at 0–50% longitudinal strain. NED occurred across the range of Pci and strains studied but was most pronounced for the chamber open condition. With a sealed chamber, V̇ increased and Pc decreased with increasing Pu − Pd until the onset of NED at V̇max and a Pc value that was designated as critical (Pcc). Pcc was lowest (−17 cmH20) and V̇max was highest (~5 l/s) with chamber sealed: Pci = 0 cmH2O and 12.5 to 25% strain. We conclude that for our collapsible tube model, the achievable V̇max before the onset of NED depends on both the initial conditions (Pci and strain) and the dynamics of feedback between driving pressure and chamber pressure (chamber sealed vs. open). NED-based phenotypic analyses for OSA may need to focus on potential feedback control mechanisms (eg lung volume change, muscle activity) that may link peripharyngeal tissue pressure levels to driving pressures for airflow. NEW & NOTEWORTHY A collapsible tube, pharyngeal airway bench model was used to study the role of surrounding pressure and longitudinal wall strain at the onset of negative effort dependence (NED). NED occurred to varying degrees across all conditions tested, but maximum airflow was achieved with 1) low initial surrounding pressure, 2) a feedback mechanism between surrounding pressure and driving pressure; and 3) a moderate amount of strain applied. Potential impacts on OSA phenotypic analyses are discussed.