Palyno-anatomical characters and their systematic significance in the family Apiaceae from Chitral,eastern Hindu Kush,Pakistan

The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies. In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 μm and equatorial diameter of 21.6 μm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 μm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 × 42.50 μm in Bupleurum falcatum subsp. cernuum and 77.25 × 26.35 μm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 × 20.05 μm and abaxial 50.25 × 39.40 μm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.     

Recent Applications of Polymer Blends in Gas Separation Membranes

Polymeric membranes are extensively used for gas separations but their performance is limited by the upper bound trade‐off discovered by Robeson in 1991. Among the attractive modifications available to increase the performance of polymeric membranes, polymer blending is a unique technique because it offers a time‐ and cost‐effective method of tuning the properties of membranes. A variety of polymer blends has been explored in recent years. The application of polymer blends in gas separation membranes is described by critically analyzing the performance of polymer blend membranes. Polymer blend membranes of different polymer pairs are reviewed and evaluated in terms of phase behavior, permeability, and selectivity.     

Investigation of active slip-systems in some body-centered cubic metals

Tensile tests were performed on high-purity W and Mo polycrystals at room temperature for a range of axial strain-rates 2.1 × 10⁻⁴–2.1 × 10⁻² s⁻¹. The critical resolved shear stress (CRSS) data was analyzed by using the analytical formulation for the strain-rate dependence of the CRSS derived in the kink-pair nucleation (KPN) model of flow stress in crystals with high intrinsic lattice friction. On evaluation of various microscopic slip-parameters of the model, the active slip-system in both W and Mo polycrystals was identified as {110}〈111〉. This is in good agreement with that deduced from the published data on the temperature dependence of the CRSS of these crystals as well as from the observed slip-lines on the deformed crystals reported in the literature. Moreover, the available data on the temperature dependence of the CRSS of Mo, Nb, Fe, V, and K crystals were also analyzed within the framework of the KPN model of flow stress. Peierls mechanism was found to be responsible for the CRSS of these metals; the active slip-systems in refractory metals Mo, Nb, Fe, and V were {110}〈111〉 and {211}〈111〉 whereas that in alkali metal K was {321}〈111〉.     

Ki-1 large cell anaplastic lymphoma--a clinicopathological study

Ki-1 large cell anaplastic lymphoma is a recently described variant of malignant lymphoma. A retrospective study of 10 cases of Ki-1 lymphoma was carried out at the Armed Forces Institute of Pathology (AFIP) Rawalpindi to document its clinical and morphological features. The morphological features were evaluated by a study of paraffin embedded sections stained with haematoxylin and eosin stains. Immunohistochemical stains for BER-H2 and leucocyte common antigen (LCA) were performed in all cases. The age of the patients ranged from 2 to 60 years and male to female ratio was 2.3:1. Cervical lymphadenopathy was the most common presentation. Histologically, there was a complete effacement of the lymph node architecture in 8 cases. The Reed-Sternberg like cells were seen in 2 and histiocyte like cells in 7 cases. Immunohistochemically all cases were positive for BER-H2. It is suggested that the possibility of Ki-1 lymphoma should be considered in all cases of lymphoma with pleomorphic morphology.     

Investigating Schizocarp morphology as a taxonomic tool in study of Apiaceae family by utilizing LM and SEM techniques

In present study, the schizocarp morphology of 14 species belonging to Apiaceae family has been investigated. Light microscopy (LM) and scanning electron microscopy (SEM) have been utilized to highlight qualitative and quantitative features of studied species. Variations have been observed in macro‐ and micro‐morphological features such as color, shape, symmetry, length, width, apex, epicuticular projections, surface patterns, anticlinal, and periclinal wall patterns. Schizocarp shapes observed were oval, round, triangular, linear, elliptic, and globose. Fruit was either homomorphic or heteromorphic. Crystalloids, stellate hair, multicellular spines, and platelets were mostly observed epicuticular projections. Surface patterns on the fruit surface were striate, rugulate‐striate, reticulate, and striato‐knotted. Both macro‐ and micro‐morphological characters can serve as an important tool in classifying Apiaceae family at various taxonomic ranks. Substantial variations observed can assist as useful constraints at various taxonomic levels as they provide reliable and constant details. Disparities observed in schizocarp features can pave a path for Apiaceae family classification based on phylogenetic and molecular studies.     

Taxonomic study of subfamily Nepetoideae (Lamiaceae) by polynomorphological approach

The present study is insight into pollen morphology for characterizing species and their utility in the taxonomic separation of certain taxa of subfamily Nepetoideae (Lamiaceae) from Pakistan. The pollen micromorphology of 11 species of the Nepetoideae was analyzed and documented using light microscopy and scanning electron microscopy (SEM) for both qualitative and quantitative characteristics. Most species have hexazonocolpate pollen grains but trizonocolpate and tetrazonocolpate pollen with circular and oval amb were also rarely observed in Mentha spicata. The basic pollen shape in most of the studied species was subspheroidal but prolate grains were also observed in M. spicata, S. coccinea, and S. plebeia. The exine sculpturing of Nepetoideae pollen was taxonomically very informative particularly at subfamily level. Observations of exine sculpturing with SEM revealed various types of pollen grains: reticulate, bireticulate, microreticulate, perforate, aerolate, and gammate. The bireticulate type further subdivided into three subtypes based on the number of secondary lumina in each primary lumen and is characterized by varying characteristics of the secondary reticulum and primary muri. A significant variation was observed in colpus surface ornamentation. The maximum polar diameter was found in O. americanum (58 ± 5.8 μm) and the maximum equatorial diameter observed in O. basilicum (50.25 ± 1.37 μm). Pollen features of the studied species were discussed and compared based on the current taxonomical concepts. The results showed that pollen traits of the subfamily Nepetoideae was found significant to classify the taxa. Furthermore, pollen features provide additional evidence to distinguish macromorphologically similar taxa from each other.     

Morpho‐palynological investigations of natural resources: A case study of Surghar mountain district Mianwali Punjab,Pakistan

Surghar mountain belt has comparatively less natural resources of floral diversity because it is composed of minerals of different kinds making it less favorable for the growth of different vegetation. The pollen morphology of some selected plants from Surghar belt Mainwali has been evaluated. The pollen grains were measured and demonstrated using scanning electron microscopy (SEM). The examined plant specimens have a difference in size, shape, polarity, and their exine ornamentation. The pollen taxa show a huge variation in size and sculpture. Pollen fertility has also been estimated, shows that the selected plants are well‐known in the Surghar belt. The need of the hour is to conserve these plants having a higher fertility rate to cope with the deforestation in an area. The conclusion does not favor theories in which deforestation results in fast growth in population. It shows that the irrational management and unlawful cutting down of woods neglected by the forest department are the main causes of deforestation in the mountain belt of Mianwali. The findings show the importance of morphological characteristics in the identification of natural resource species in the area.