Stein-type shrinkage estimators in gamma regression model with application to prostate cancer data.

Gamma regression is applied in several areas such as life testing, forecasting cancer incidences, genomics, rainfall prediction, experimental designs, and quality control. Gamma regression models allow for a monotone and no constant hazard in survival models. Owing to the broad applicability of gamma regression, we propose some novel and improved methods to estimate the coefficients of gamma regression model. We combine the unrestricted maximum likelihood (ML) estimators and the estimators that are restricted by linear hypothesis, and we present Stein-type shrinkage estimators (SEs). We then develop an asymptotic theory for SEs and obtain their asymptotic quadratic risks. In addition, we conduct Monte Carlo simulations to study the performance of the estimators in terms of their simulated relative efficiencies. It is evident from our studies that the proposed SEs outperform the usual ML estimators. Furthermore, some tabular and graphical representations are given as proofs of our assertions. This study is finally ended by appraising the performance of our estimators for a real prostate cancer data.

Faster Biomineralization and Tailored Mechanical Properties of Marine-Resource-Derived Hydroxyapatite Scaffolds with Tunable Interconnected Porous Architecture.

Although hydroxyapatite (HA)-based porous scaffolds have been widely researched in the last three decades, the development of naturally derived biomimetic HA with a tunable elastic modulus and strength together with faster biomineralization properties has not yet been achieved. To address this specific issue, we report here a scalable biogenic synthesis approach to obtain submicron HA powders from cuttlefish bone. The marine-resource-derived HA together with different pore formers can be conventionally sintered to produce physiologically relevant scaffolds with porous architecture. Depending on pore formers, the scaffolds with a range of porosity of up to 51% with a larger range of pore sizes up to 50 µm were fabricated. An empirical relationship between the compression strength and the elastic modulus with fractional porosity was established. A combination of moderate compressive strength (12-15 MPa) with an elastic modulus up to 1.6 GPa was obtained from cuttlefish-bone-derived HA with wheat flour as the pore former. Most importantly, the specific HA scaffold supports the faster nucleation and growth of the biomineralized apatite layer with full coverage within 3 days of incubation in simulated body fluid. More importantly, the marine-species-derived HA supported better adhesion and proliferation of murine osteoblast cells than HA sintered using powders from nonbiogenic resources. The spectrum of physical and biomineralization properties makes cuttlefish-bone-derived porous HA a new generation of implantable biomaterial for potential application in cancellous bone regeneration.

Primary pelvic hydatid cyst in a postmenopausal female: a surgical challenge.

Primary pelvic hydatid cysts are a rare entity and are often overlooked as a differential diagnosis of a pelvic-space-occupying lesion particularly in non-endemic regions. Unpreparedness and a hasty decision on the surgical approach may end in life-threatening complications and systemic dissemination of the disease. We report the case of a 55-year-old postmenopausal woman with a history of two previous unsuccessful surgeries to remove pelvic cystic lesions due to dense adhesions between the surrounding gut wall, bladder, and the cyst wall. Clinical and imaging findings failed to diagnose the nature of the cysts, and a laparotomy was contemplated. On the third surgical attempt, the clinical suspicion was considered and by meticulous dissection the cysts were removed thoroughly without undue complications. In the postoperative follow-up period there was no sign of disease recurrence or dissemination.

Primary pelvic hydatid cyst in a postmenopausal female: a surgical challenge

Primary pelvic hydatid cysts are a rare entity and are often overlooked as a differential diagnosis of a pelvic-space-occupying lesion particularly in non-endemic regions. Unpreparedness and a hasty decision on the surgical approach may end in life-threatening complications and systemic dissemination of the disease. We report the case of a 55-year-old postmenopausal woman with a history of two previous unsuccessful surgeries to remove pelvic cystic lesions due to dense adhesions between the surrounding gut wall, bladder, and the cyst wall. Clinical and imaging findings failed to diagnose the nature of the cysts, and a laparotomy was contemplated. On the third surgical attempt, the clinical suspicion was considered and by meticulous dissection the cysts were removed thoroughly without undue complications. In the postoperative follow-up period there was no sign of disease recurrence or dissemination.

Purification of PEDOT:PSS by Ultrafiltration for Highly Conductive Transparent Electrode of All-Printed Organic Devices.

A highly conductive, air stable and scalable poly(3,4-ethylenedioxythiophene) (PEDOT): poly(4-styrenesulfonate) (PEDOT:PSS) are prepared by using mass production ultrafiltration. By effectively removing excess PSS and various reaction impurities using repeated 100 nm pore membrane filtration, purified PEDOT:PSS exhibit conductivity as high as 2000 S cm-1 .

Shift-invariant target in allocation problems.

We provide a template for finding target allocation proportions in optimal allocation designs where the target will be invariant for both shifts in location and scale of the response distributions. One possible application of such target allocation proportions is to carry out a response-adaptive allocation. While most of the existing designs are invariant for any change in scale of the underlying distributions, they are not location invariant in most of the cases. First, we indicate this serious flaw in the existing literature and illustrate how this lack of location invariance makes the performance of the designs very poor in terms of allocation for any drastic change in location, such as the changes from degrees centigrade to degrees Fahrenheit. We illustrate that unless a target allocation is location invariant, it might lead to a completely irrelevant and useless target for allocation. Then we discuss how such location invariance can be achieved for general continuous responses. We illustrate the proposed method using some real clinical trial data. We also indicate the possible extension of the procedure for more than two treatments at hand and in the presence of covariates.