Computer Studies Made Simple : Different Components Of Local Area Networks:

Different Components Of Local Area Networks

Following are various components of a Local Area Network

Gateway

Router

Bridge

Network Interface Card

Communication Medium

Gateway:

This device connects networks together and converts the data according to the type of protocol

And thus can connect multiple networks with different types of protocol together.

Router:

This device connects multiple networks with various types of protocols together and can also be used if networs are operating in various countries

Bridge:

This device is used to connect similar types of networks

Network Interface Card:

This type of device physically connects a computer to a network and controls flow of information between computer and network.

Communication Medium:

This refers to medium that are used to connect different computers for the purpose of data transfer.

The major types of this medium include:

Co-axial cables

Fibreoptic cables

Endocrinology Made Simple : Causes Of Hypercalcemia

Causes Of Hypercalcemia

The causes of Hypercalcemia can be broadly divided into following two types :

1.Parathyroid Dependent

2.Parathyroid Independent

1.Parathyroid Dependent Hypercalcemia:

These may be.      

          

      a      Primary Hyperparathyroidsim

      b.      Tertiary Hyperparathyroidism

   

      c.       Lithium Induced Hypercalcemia

     

      d.      Familial Hypocalciuric Hypercalcemia

2 . Parathyroid Independent Hypercalcemia:

The causes of these are as follows:

       a.Malignancies

       b.Vitamin D Toxicity

       c.Granulomatous Disease

       d.Milk Alkali Syndrome

Malignancy Induced Hypercalcemia:

This occurs due to secretion of PTHrP and other haematological malignancies

It is important to measure serum PTH levels in order to classify if hypercalcemia is PTH Dependent or PTH 

Independent.

Dermatology Made Simple : Skin lesions caused by Medications 3:

Contact Dermatitis:

This usually occurs at areas of contact with medications/ointments etc to the skin

It occurs after months of exposure to the medication.

Usually the medication is in form of ointment,gel or topical patch.

Some of the medications that can cause this include:

Oestradiol

Clonidine

Nitroglycerin

Allergic contact Dermatitis

Management:

Avoidance of causative agent.

Topical steroids

Fixed Drug Eruption:

These are skin lesions that occur at the same site of skin repeatedly whenever an individual gets exposed to a medications to which he has developed allergy.

These maybe single or multiple lesions.

Common medications that cause this lesion include:

Fluconazole

Ciprofloxacin

Doxycycline

Clarithromycin

NSAIDs

Trimethoprim

Cotrimoxazole

Phenytoin

Cetirizine

Management:

Identifications and Avoidance of the causative agent

Topical steroid application at site of the lesion

Computer studies Made Simple : Local Area Network / LAN

Local Area Network / LAN

Local Area Network are used to connect computers in a single building or group of buildings.

Types of LAN/Local Area Networks

There are many types of LANs

The most common type is Ehernet.

Composition of LAN :

A Local Area Network consists of  a central node which is alos called as network Hub.

The computers in LAN are connected to the central node in a star topology.

These links between the hub and computers is made with UTP cables/Unsheilded Twisted Pair Cables.

The maximum recommended length for a UTP cable in LAN is 100 meters.

The computers in a LAN communicate with each other at a high speed.

The speed of communication between 2 devices in a LAN varies between 2 to 1000 million bits/second
Mbps.

No computer in a LAN should be more than 100 meters from the central hub,hence,LAN can transmit data
only in a limited distance.

That is why LAN are mostly used to connect computers in a single building or room etc.








UTP Cables


 Local Area Network

Advantages  and Applications of LAN:

1.Data is shared by all users in the network  

2.The data transfer is very secure from getting copied and there are lesser chances of it getting destroyed or
corrupted.

3.It can help sharing of utility devices such as Printer easier between users in the network.

4.A single software canbe used by all users in the network.

5.Data is stored in a central computer and hence can be esily used by all users in the network.

Dermatology Made Simple : Skin lesions caused by Drugs

Skin lesions caused by Drugs

Drug Induced Vasculitis

Vasculitis is inflammation of blood vessels that can cause their complete occlusion or lead to leakage of blood components through the vessel wall.

The inflammation can affect any of the vessels in the skin including capillaries, venules, arterioles and lymphatics.

The chief drugs involved in causing vasculitis are as follows:

Thiazide diuretics

Thiouracil

Antibiotics

Nonsteroidal anti-inflammatory drugs (NSAIDs)

Oral anticoagulants ( warfarin and coumarin).

 skin vasculitis

Mechanism of Drug Induced Vasculitis :

Both  cell mediated and humoral immunity are thought to play a role.

The most common encountered skin rash is non blanching purpura on the limbs.

Treatment involves:

Withdrawing the offending drug

Administration of systemic steroids

Erythema Multiforme:

Erythema multiforme (EM) is an acute, self-limited, and sometimes recurring skin condition that is considered to be a type IV hypersensitivity reaction associated with certain infections, medications, and other various triggers

The characterstic rash is called as  target lesions that involve elbows,face and palms.

These lesions have a central vesicle and are erythematous.

There may or may not be some systemic features associated with this rash  

  Erythema multiforme

Precipitating factors include 

Herpes simplex virus (HSV) 

Epstein-Barr virus (EBV)

Histoplasmosis

Mycoplasma

Erythema multiforme represents mild end of spectrum of skin conditons with Steven Johnson”s syndrome the severest.

Following is a list of medications that cause Erythema multiforme:

Barbiturates

Non-steroidal anti-inflammatory drugs

Penicillins

Sulphonamides

Phenothiazines  

Anticonvulsants.

Diagnosis

This is usually clinical but in case of doubt,skin biopsy is diagnostic that show on histology necrotic 

keratinocytes,lymphocytic infiltrate and blister formation

Management:

This is usually achieved by stopping the causative medication and applications of topical steroids

Erythema Multiforme  major may require hospital admission for supportive care

Oral antihistamines and/or topical corticosteroids may help relieve itching.

Following treatments t have been reported to help suppress recurrent Erythema Multiforme:

Antimalarial drugs eg hydroxychloroquine

Dapsone 100-150mg/d

Azathioprine 100-150 mg/d

Miscellaneous Drugs in Resistant cases:

Ciclosporin,

Mycophenolate mofetil

Photochemotherapy (PUVA)

Thalidomide